InvertebrataInvertebrata

NemathodaNemathoda

OlehOleh Amirur RozakAmirur RozakMonica Sani T.Monica Sani T.

Rizki Marudur S.Rizki Marudur S.Nitya Wulandari Nitya Wulandari Rezeki suci M.Rezeki suci M.

SMAN

1

TEGAL

Identification 5 kingdomIdentification 5 kingdom

- The basis classification used by taxonomist is the similarities and differences in characteristics of morphology, physiology, and anatomy. The group of organism found from the result of classification are called taxon. The taxon formation is regularly gradded. Each taxon level is given a certain name. The classification level from the highest level (kingdom) until the lowest level (spesies) are as follow.

KINGDOM / REGNUMKINGDOM / REGNUM

PHYLUM / DIVISIPHYLUM / DIVISI

CLASSCLASS

ORDOORDO

FAMILIAFAMILIA

GENUSGENUS

SPESIESSPESIES

KINGDOMKINGDOMKingdom is the biggest group of living organism known by biologist. Classification system which Kingdom is the biggest group of living organism known by biologist. Classification system which now still used is the classification of 5 kingdom which purposed by R.H. Whittaker, that is now still used is the classification of 5 kingdom which purposed by R.H. Whittaker, that is monera, prostist, fungi, plantae, and animalia. Classification 5 kingdoms is based on cell type, monera, prostist, fungi, plantae, and animalia. Classification 5 kingdoms is based on cell type, uncelluler or multicelluler, and nutrition type.uncelluler or multicelluler, and nutrition type.

- Animalia kingdom- Animalia kingdom animal are the group of eukaryotic organisms from the kingdom of animalia which animal are the group of eukaryotic organisms from the kingdom of animalia which

have multicelluler property, have the ability to move from one place to another, and heterotrop. have multicelluler property, have the ability to move from one place to another, and heterotrop. Different from the plant, all of animals can move the parts of their body and have ability to move Different from the plant, all of animals can move the parts of their body and have ability to move their body. Animal reproduce by sexual or asexual way. Sexual can happen if egg cell meet their body. Animal reproduce by sexual or asexual way. Sexual can happen if egg cell meet sperm to form zygote. While asexual reproduction happens by everal method, such as sperm to form zygote. While asexual reproduction happens by everal method, such as fragmentation, binnary fission, and budding formation.fragmentation, binnary fission, and budding formation.- The kingdom of animal consist nine phylum, that is: - The kingdom of animal consist nine phylum, that is:

1. Porifera1. Porifera2. Cnidaria2. Cnidaria3. Platyhelminthes3. Platyhelminthes4. Nematelminthes 4. Nematelminthes 5. Annelida 5. Annelida 6. Mollusca6. Mollusca7. Antrophoda7. Antrophoda8. Echinodermata8. Echinodermata9. Chordata 9. Chordata

- - Animal kingdom are divided into two group based on presence or absence of backbone, Animal kingdom are divided into two group based on presence or absence of backbone, that isthat is 1. Vertebrata (have backbone)1. Vertebrata (have backbone)2. Invertebrata (doesn’t have backbone)2. Invertebrata (doesn’t have backbone)

Invertebrata Invertebrata Invertebrate is the group of animal which has no backbone. The number of member is Invertebrate is the group of animal which has no backbone. The number of member is

about 98% of entire animal kingdom. In the food chain, Invertebrate have a role as primary and about 98% of entire animal kingdom. In the food chain, Invertebrate have a role as primary and secondary consumer also decomposer. Invertebrate occupy all of habitat in earth surface. The secondary consumer also decomposer. Invertebrate occupy all of habitat in earth surface. The living method of Invertebrate are solitary or make colony. Some are sedentary (live one place) or living method of Invertebrate are solitary or make colony. Some are sedentary (live one place) or attach a substrate and some move. Invertebrate reproduce by asexual and sexual. Asexual attach a substrate and some move. Invertebrate reproduce by asexual and sexual. Asexual reproduction happens with dividing itself, budding and partenogenesis. While sexual reproduction reproduction happens with dividing itself, budding and partenogenesis. While sexual reproduction by fertilization of male gamet and female gamete. by fertilization of male gamet and female gamete.

There are several ways to divided invertebrata into different main types or phyla:There are several ways to divided invertebrata into different main types or phyla:

1. According to the true body tissue1. According to the true body tissue

- Parazoa : have no tissue (porifera)- Parazoa : have no tissue (porifera)

- Eumetazoa : have true tissue (Cnidaria, Platyhelminthes, Nematelminthes, - Eumetazoa : have true tissue (Cnidaria, Platyhelminthes, Nematelminthes, Annelida, Annelida, Mollusca, Echinodermata, and Antrophoda)Mollusca, Echinodermata, and Antrophoda)

2. According to the overall pattern of body form2. According to the overall pattern of body form

- Asymmetry (antrophoda)- Asymmetry (antrophoda)

- Radial symmetry (porifera)- Radial symmetry (porifera)

- Bilateral symmetry (Nematelminthes) - Bilateral symmetry (Nematelminthes)

3. According the body cavity3. According the body cavity

- Acoelomate- Acoelomate

- Pseudocoelomate (Nematelminthes)- Pseudocoelomate (Nematelminthes)

- coelomate - coelomate

Nematelminthes

References References A. M. A. Aguinaldo, J. M. Turbeville, L. S. Linford, M. C. Rivera, J. R. Garey, R. A. Raff, & J. A. A. M. A. Aguinaldo, J. M. Turbeville, L. S. Linford, M. C. Rivera, J. R. Garey, R. A. Raff, & J. A.

Lake, 1997. Evidence for a clade of nematodes, arthropods and other moulting animals. Nature Lake, 1997. Evidence for a clade of nematodes, arthropods and other moulting animals. Nature 387: 489-493. 387: 489-493.

R. Buchsbaum, M. Buchsbaum, J. Pearse, & V. Pearse, 1987. R. Buchsbaum, M. Buchsbaum, J. Pearse, & V. Pearse, 1987. Animals Without BackbonesAnimals Without Backbones. . Chicago: University of Chicago Press. Chicago: University of Chicago Press.

T. I. Storer, R. L. Usinger, R. C. Stebbins, & J. W. Nybakken, 1979. T. I. Storer, R. L. Usinger, R. C. Stebbins, & J. W. Nybakken, 1979. General ZoologyGeneral Zoology, 6th edition. , 6th edition. New York: McGraw-Hill Book Company. New York: McGraw-Hill Book Company.

Wallace, Robert Lee, Claudia Ricci, & Giulio Melone, 1996. A cladistic analysis of Wallace, Robert Lee, Claudia Ricci, & Giulio Melone, 1996. A cladistic analysis of pseudocoelomate (aschelminth) morphology. Invertebrate Biology 115(2): 104-112.pseudocoelomate (aschelminth) morphology. Invertebrate Biology 115(2): 104-112.

Tree of Life Web Project (ToL) (2002b): Nematoda. Version of 2002-JAN-01. Retrieved 2008-Tree of Life Web Project (ToL) (2002b): Nematoda. Version of 2002-JAN-01. Retrieved 2008-NOV-02.NOV-02.

Baird JK, Mistrey M, Pimsler M, Connor DH (March 1986). "Fatal human ascariasis following Baird JK, Mistrey M, Pimsler M, Connor DH (March 1986). "Fatal human ascariasis following secondary massive infection". secondary massive infection". Am. J. Trop. Med. Hyg.Am. J. Trop. Med. Hyg. 3535 (2): 314–8. PMID 3953945 (2): 314–8. PMID 3953945

http: en/wikipedia.com/wiki/nematodahttp: en/wikipedia.com/wiki/nematoda Hotez PJ, Pritchard DI (June 1995). "Hookworm infection". Hotez PJ, Pritchard DI (June 1995). "Hookworm infection". Sci. Am.Sci. Am. 272272 (6): 68–74. PMID (6): 68–74. PMID

77618177761817 "Pinworm". Encyclopædia Britannica. "Pinworm". Encyclopædia Britannica.

http://www.britannica.com/EBchecked/topic/461262/pinworm. Retrieved on 2009-04-08. http://www.britannica.com/EBchecked/topic/461262/pinworm. Retrieved on 2009-04-08.

NEMATHODENEMATHODE

INTRODUCTIONINTRODUCTION CLASSIFICATIONCLASSIFICATION

CHARACTERISTICCHARACTERISTIC

REPRODUCTIONREPRODUCTION

MEMBER OF NEMATHODAMEMBER OF NEMATHODA

LIVING ENVIRONMENTLIVING ENVIRONMENT

WAY OF LIVEWAY OF LIVE

BENEFIT AND LOSSBENEFIT AND LOSS

CONCLUSIONCONCLUSION

NUTRITIONNUTRITION MORPHOLOGYMORPHOLOGY

Introduction Introduction

The "roundworms" or "nematodes" (phylum The "roundworms" or "nematodes" (phylum NematodaNematoda) are the most diverse ) are the most diverse phylum of phylum of pseudocoelomatespseudocoelomates, and one of the most diverse of all animals. Nematode species , and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 80,000 have been described, of which over 15,000 are are very difficult to distinguish; over 80,000 have been described, of which over 15,000 are parasitic. It has been estimated that the total number of described and undescribed roundworms parasitic. It has been estimated that the total number of described and undescribed roundworms might be more than 500,000. Unlike cnidarians or flatworms, roundworms have a digestive might be more than 500,000. Unlike cnidarians or flatworms, roundworms have a digestive system that is like a tube at both ends.system that is like a tube at both ends.

Nematodes have successfully adapted to nearly every ecological niche from marine Nematodes have successfully adapted to nearly every ecological niche from marine to fresh water, from the polar regions to the tropics, as well as the highest to the lowest of to fresh water, from the polar regions to the tropics, as well as the highest to the lowest of elevations. They are ubiquitous in freshwater, marine, and terrestrial environments, where they elevations. They are ubiquitous in freshwater, marine, and terrestrial environments, where they often outnumber other animals in both individual and species counts, and are found in locations often outnumber other animals in both individual and species counts, and are found in locations as diverse as Antarctica and oceanic trenches. They represent, for example, 90% of all life on as diverse as Antarctica and oceanic trenches. They represent, for example, 90% of all life on the seafloor of the Earth. The many parasitic forms include pathogens in most plants, animals, the seafloor of the Earth. The many parasitic forms include pathogens in most plants, animals, and also in humansand also in humans

ClassificationClassificationPhylum Class Order

Nematoda

Adenophorea

Enoplida

Isolaimida

Mononchida

Dorylaimida

Trichocephalida

Mermithida

Muspiceida

Araeolaimida

Chromadorida

Desmoscolecida

Desmodorida

Monhysterida

Secernentea

Rhabdita

Strongylida

Ascaridida

Spirurida

Camallanida

Diplogasterida

Tylenchida

Aphelenchida

Nematode systematicsNematode systematicsDue to the lack of knowledge regarding Due to the lack of knowledge regarding many nematodes, their systematics is many nematodes, their systematics is contentious. Traditionally, they are divided contentious. Traditionally, they are divided into two into two classesclasses, the , the AdenophoreaAdenophorea and the and the SecernenteaSecernentea, and initial DNA sequence , and initial DNA sequence studies suggested the existence of five studies suggested the existence of five clades:clades:

DorylaimidaEnoplida Spirurida

TylenchidaRhabdita

As it seems, the Secernentea are indeed a As it seems, the Secernentea are indeed a natural group of closest relatives. But the natural group of closest relatives. But the "Adenophorea" appear to be a paraphyletic "Adenophorea" appear to be a paraphyletic assemblage of roundworms simply assemblage of roundworms simply retaining a good number of ancestral traits. retaining a good number of ancestral traits. The Enoplida do not seem to be The Enoplida do not seem to be monophyletic either but to contain two monophyletic either but to contain two distinct lineages. The old group distinct lineages. The old group "Chromadoria" seem to be another "Chromadoria" seem to be another paraphyletic assemblage, with the paraphyletic assemblage, with the Monhysterida representing a very ancient Monhysterida representing a very ancient minor group of nematodes. Among the minor group of nematodes. Among the Secernentea, the Diplogasteria may need Secernentea, the Diplogasteria may need to be united with the Rhabdita. while the to be united with the Rhabdita. while the Tylenchida might be paraphyletic with the Tylenchida might be paraphyletic with the Rhabdita.Rhabdita.

• Adenophorea

Adenophorea is a class of nematodes. They are unsegmented worms.Characteristics of adenophorea are:•amphids always post-labial, variable shape, pore-like to elaborate •deirids are not seen •phasmids are generally absent •hypodermal glands resent (excretory) uninucleate •simple non-tubular excretory system when present •three caudal glands commonly opening through a spinneret at the tail tip •male generally has two testes •caudal alae are rare •male with supplement glands in a single ventro-median row •sensory papillae in cephalic region and along the body •generally there are five esophageal glands •marine, freshwater, terrestrial

MononchidaeMononchidae

ExampleExample

SecernenteaSecernentea

SecernenteaSecernentea are the main class of nematodes, are the main class of nematodes, characterised by numerous and an excretory system characterised by numerous and an excretory system possessing lateral canals. Like all nematodes, they have no possessing lateral canals. Like all nematodes, they have no circulatory or respiratory system.circulatory or respiratory system.

The Secernentea contain several significant The Secernentea contain several significant parasitic species among the Rhabditia and Spiruria. parasitic species among the Rhabditia and Spiruria. Caenorhabditis elegansCaenorhabditis elegans, the famous laboratory animal, is , the famous laboratory animal, is one of the many harmless members of the Rhabditia.one of the many harmless members of the Rhabditia.

SystematicsSystematicsSubclasses and orders of Secernentea are:- Subclass Rhabditia (paraphyletic?) - Subclass Rhabditia (paraphyletic?)

Rhabditida Rhabditida Strongylida Strongylida

- Subclass Spiruria - Subclass Spiruria Ascaridida Ascaridida Camallanida (sometimes included in Spirurida) Camallanida (sometimes included in Spirurida) (sometimes included in Spirurida) (sometimes included in Spirurida) Oxyurida Oxyurida (formerly in Tylenchida) (formerly in Tylenchida) Spirurida Spirurida

- Subclass Diplogasteria (may belong in Rhabdita) - Subclass Diplogasteria (may belong in Rhabdita) Diplogasterida Diplogasterida

- Subclass (may belong in Rhabdita) - Subclass (may belong in Rhabdita) Aphelenchida Aphelenchida Tylenchida Tylenchida

- Order - Order incertae sedisincertae sedis

ExampleExample

Ancylostoma caninum – a hookwormattached to the intestine of a dog, though species of hookworm infect other mammals including humans. The name comes from them being bent over at the head end so forming a hook.

Characteristic Characteristic

Characteristics of Nematode:Characteristics of Nematode: 1)Bilaterally symmetrical, and vermiform. 1)Bilaterally symmetrical, and vermiform. 2)Body has more than two cell layers, tissues and organs. 2)Body has more than two cell layers, tissues and organs. 3)Body cavity is a pseudocoel, body fluid under high pressure. 3)Body cavity is a pseudocoel, body fluid under high pressure. 4)Body possesses a through gut with a subterminal anus. 4)Body possesses a through gut with a subterminal anus. 5)Body covered in a complex cuticle. 5)Body covered in a complex cuticle. 6)Has a nervous system with pharyngeal nerve ring. 6)Has a nervous system with pharyngeal nerve ring. 7)Has no circulatory system (no blood system) 7)Has no circulatory system (no blood system) 8)Reproduction normally sexual and gonochoristic (internal fertilization). 8)Reproduction normally sexual and gonochoristic (internal fertilization). 9)Live just about everywhere, many species are endoparasites 9)Live just about everywhere, many species are endoparasites

Living environment Living environment

Mostly, nemathode live at sediment layers in water (both Mostly, nemathode live at sediment layers in water (both marine water and fresh water), and are abundant soil marine water and fresh water), and are abundant soil

NutritionNutrition

Nematodes normally eat bacteria, fungi and protozoans, although some are filter Nematodes normally eat bacteria, fungi and protozoans, although some are filter feeders. Excretion happens through a separate excretory pore. Nematodes also feeders. Excretion happens through a separate excretory pore. Nematodes also contract bacterial infections within excretion pores.contract bacterial infections within excretion pores.

1. Herbivores. These are the plant parasites, which are relatively well known. This group includes many members of the order Tylenchida, as well as a few genera in the orders Aphelenchida and Dorylaimida. The mouthpart is a needlelike stylet which is used to puncture cells during feeding. Ectoparasites remain in the soil and feed at the root surface. Endoparasites enter roots and can live and feed within the root.

.

2. Bacterivores. Many kinds of free-living nematodes feed only on bacteria,which are always extremelyabundant in soil. In these nematodes, the "mouth", or stoma, is a hollow tube for ingestion of bacteria. This group includes many members of the order Rhabditida as well as several other orders which are encountered less often. These nematodes are beneficial in the decomposition of organic matter

In the herbivore, the mouthpart is modified into a stylet for puncturing plant cells.

In the bacterivore, the mouth or stoma is a hollow tube.

Way of liveWay of live

3. Omnivores. The food habits of most nematodes in soil are relatively specific. For example, bacterivores feed only on bacteria and never on plant roots, and the opposite is true for plant parasites. A few kinds of nematodes may feed on more than one type of food material, and therefore are considered omnivores. For example, some nematodes may ingest fungal spores as well as bacteria. Some members of the order Dorylaimida may feed on fungi, algae, and other animals.

4. Predators. These nematodes feed on other soil nematodes and on other

animals of comparable size. They feed indiscriminately on both plant parasitic and free-living nematodes. One order of nematodes, the Mononchida, is exclusively predacious, although a few predators are also found in the Dorylaimida and some other orders. Compared to the other groups of nematodes, predators are not common, but some of them can be found in most soils.

5. Fungivores. This group of nematodes feeds on fungi and uses a stylet to puncture fungal hyphae. Many members of the order Aphelenchida are in this group. Like the bacterivores, fungivores are very important in decomposition.

6. Unknown. Since free-living nematodes have not been studied very much, the food habits of some of them are unknown. The microscopic size of these animals presents additional difficulties. For example, it can be very difficult to distinguish whether a nematode is feeding on dead cells from a plant root or on fungi growing on the cell surface. Sometimes a nematode showing this feeding behavior may be classified simply as a root or plant associate.

Community Composition

Basically a Nematode is a long hollow tube within which is another tube, the alimentary canal Basically a Nematode is a long hollow tube within which is another tube, the alimentary canal and the reproductive organs. Nematodes are round in cross section, this is because unlike the other and the reproductive organs. Nematodes are round in cross section, this is because unlike the other worms that below them in the phyla table they maintain their body fluids under great pressure. To contain worms that below them in the phyla table they maintain their body fluids under great pressure. To contain this high pressure nematodes have an extremely tough, yet elastic and flexible cuticle. This cuticle this high pressure nematodes have an extremely tough, yet elastic and flexible cuticle. This cuticle consists of up to 9 layers of proteinaceous fibres, with 3 layers being easily discerned, these are called, consists of up to 9 layers of proteinaceous fibres, with 3 layers being easily discerned, these are called, from the outside in, the cortex, the matrix layer and the fibre layer. Despite its complexity the Nematode from the outside in, the cortex, the matrix layer and the fibre layer. Despite its complexity the Nematode cuticle is permeable to both water and gases, so respiration occurs through it. Beneath the cuticle is a cuticle is permeable to both water and gases, so respiration occurs through it. Beneath the cuticle is a hypodermis and a layer of longitudinal muscle. The combination of the flexure of these muscles with the hypodermis and a layer of longitudinal muscle. The combination of the flexure of these muscles with the high pressure of the system produces a characteristic whip-like wriggle that Nematodes use to swim. high pressure of the system produces a characteristic whip-like wriggle that Nematodes use to swim. Scientifically this is called undulatory propulsion with sinusoidal waves passing back along the body.Scientifically this is called undulatory propulsion with sinusoidal waves passing back along the body.

At the anterior (head) end there is a mouth which has 3 lips behind which predatory species At the anterior (head) end there is a mouth which has 3 lips behind which predatory species possess a few teeth, this leads to a pharynx which is triangular in cross section. Because of the high possess a few teeth, this leads to a pharynx which is triangular in cross section. Because of the high pressure within the body unsupported organs such as the intestines tend to collapse in much the same pressure within the body unsupported organs such as the intestines tend to collapse in much the same way that an uninflated bicycle tube tends to become oval or flat in cross section when laid flat on the table. way that an uninflated bicycle tube tends to become oval or flat in cross section when laid flat on the table. The pharynx of Nematodes is an efficient pump and forces food into the intestines, there is a one way The pharynx of Nematodes is an efficient pump and forces food into the intestines, there is a one way valve between the intestines and the pharynx. The pharynx can, when this valve is closed, be used to valve between the intestines and the pharynx. The pharynx can, when this valve is closed, be used to suck liquid food into the mouth. Digestion is rapid and faeces are expelled under pressure. This pressure suck liquid food into the mouth. Digestion is rapid and faeces are expelled under pressure. This pressure is so great that the parasitic nematode is so great that the parasitic nematode Ascaris lumbricoidesAscaris lumbricoides which is about 12cm to 18cm long (5 to 7 which is about 12cm to 18cm long (5 to 7 inches) may shoot its faeces 60cm or 2 feet into the air.inches) may shoot its faeces 60cm or 2 feet into the air.

Nematodes, especially free living forms generally have a reasonably well developed nervous Nematodes, especially free living forms generally have a reasonably well developed nervous system. This is comprised of a circum-pharyngeal nerve ring made up from 4 nerve ganglia from which 6 system. This is comprised of a circum-pharyngeal nerve ring made up from 4 nerve ganglia from which 6 longitudinal nerves extend down through the body to the various parts of the gut and the reproductive longitudinal nerves extend down through the body to the various parts of the gut and the reproductive organs. There are also 6 shorter nerves which extend forwards from the circum-pharyngeal ganglia organs. There are also 6 shorter nerves which extend forwards from the circum-pharyngeal ganglia towards the mouth. Nematodes have no circulatory or respiratory organs and the excretion of metabolic towards the mouth. Nematodes have no circulatory or respiratory organs and the excretion of metabolic waste is via two simple ducts or tubules which have no nephridia or flame cells.waste is via two simple ducts or tubules which have no nephridia or flame cells.

AnatomyAnatomy

Nematodes are copiously reproductive and most of their body cavity, which is a Nematodes are copiously reproductive and most of their body cavity, which is a pseudocoelom is filled with paired sets of reproductive organs, either ovaries or testes. Males and pseudocoelom is filled with paired sets of reproductive organs, either ovaries or testes. Males and females copulate and the male introduces sperm to the females vagina with the help of 2 stiff horny females copulate and the male introduces sperm to the females vagina with the help of 2 stiff horny spicules that are a part of his cloaca. Fertilisation is internal and females lay eggs over a prolonged spicules that are a part of his cloaca. Fertilisation is internal and females lay eggs over a prolonged time period, thus a female time period, thus a female Ascaris lumbricoidesAscaris lumbricoides may lay her eggs at the rate of 200,000 per day and may lay her eggs at the rate of 200,000 per day and have had a total 27 million eggs within her at the start of her reproductive career. Young nematodes have had a total 27 million eggs within her at the start of her reproductive career. Young nematodes hatch from these eggs and go through 4 moults before they become adultshatch from these eggs and go through 4 moults before they become adults

MorphologyMorphologyRoundworms are unsegmented, bilaterally Roundworms are unsegmented, bilaterally

symmetric and triploblastic protostomes with a complete symmetric and triploblastic protostomes with a complete digestive system. They have no circulatory or respiratory digestive system. They have no circulatory or respiratory systems so they use diffusion to breathe.systems so they use diffusion to breathe.

Although they have no circulatory system, Although they have no circulatory system, nutrients are transported throughout the body via fluid in the nutrients are transported throughout the body via fluid in the pseudocoelompseudocoelom. They are thin and are round in cross section. . They are thin and are round in cross section. Nematodes are one of the simplest animal groups to have a Nematodes are one of the simplest animal groups to have a complete digestive system, with separate orifices for food complete digestive system, with separate orifices for food intake and waste excretion, a pattern followed by all intake and waste excretion, a pattern followed by all subsequent, more complex animals. The body cavity is a subsequent, more complex animals. The body cavity is a pseudocoelompseudocoelom (persistent blastula), which lacks the muscles (persistent blastula), which lacks the muscles of coelomate animals that protects the body from drying out, of coelomate animals that protects the body from drying out, from digestive juices, or from other harsh environments. from digestive juices, or from other harsh environments. Although this cuticle allows movement and shape changes Although this cuticle allows movement and shape changes via a via a hydrostatic skeletal systemhydrostatic skeletal system, it is very inelastic so does , it is very inelastic so does not allow the volume of the worm to increase. Therefore, as not allow the volume of the worm to increase. Therefore, as the worm grows, it has to molt and form new cuticles. The the worm grows, it has to molt and form new cuticles. The cuticles don't allow volume to increase so as to keep cuticles don't allow volume to increase so as to keep hydrostatic pressure inside the organism very high. For this hydrostatic pressure inside the organism very high. For this reason, the roundworms do not possess circular muscles reason, the roundworms do not possess circular muscles (just longitudinal ones) as they're not required. This (just longitudinal ones) as they're not required. This hydrostatic pressure is the reason the roundworms are hydrostatic pressure is the reason the roundworms are round. Nematodes have a simple nervous system, with a round. Nematodes have a simple nervous system, with a main main ventral nerve cord ventral nerve cord (pic.1a) and a smaller and a smaller dorsal nerve dorsal nerve cordcord(pic.1b). Sensory structures at the anterior end are . Sensory structures at the anterior end are called called amphidsamphids, while sensory structures at the posterior end , while sensory structures at the posterior end are called are called phasmidsphasmids. There are no circular muscles, so the . There are no circular muscles, so the body can only undulate from side to side. Contact with solid body can only undulate from side to side. Contact with solid objects is necessary for locomotion; its thrashing motions objects is necessary for locomotion; its thrashing motions vary from mostly to completely ineffective at swimming.vary from mostly to completely ineffective at swimming.

Pic. 1a

Pic. 1b

MorphologyMorphology

Reproduction Reproduction Reproduction is usually sexual. Males are usually smaller than females Reproduction is usually sexual. Males are usually smaller than females

(often much smaller) and often have a characteristically bent tail for holding the (often much smaller) and often have a characteristically bent tail for holding the female for copulation. During copulation, one or more chitinized spicules move out of female for copulation. During copulation, one or more chitinized spicules move out of the cloaca and are inserted into genital pore of the female. Amoeboid sperm crawl the cloaca and are inserted into genital pore of the female. Amoeboid sperm crawl along the spicule into the female worm. Nematode sperm is thought to be the only along the spicule into the female worm. Nematode sperm is thought to be the only eukaryotic cell without the globular protein G-actin.eukaryotic cell without the globular protein G-actin.

Eggs may be embryonated or unembryonated when passed by the female, Eggs may be embryonated or unembryonated when passed by the female, meaning that their fertilized eggs may not yet be developed. In free-living meaning that their fertilized eggs may not yet be developed. In free-living roundworms, the eggs hatch into larva, which eventually grow into adults; in parasitic roundworms, the eggs hatch into larva, which eventually grow into adults; in parasitic roundworms, the life cycle is often much more complicated.roundworms, the life cycle is often much more complicated.

Nematodes as a whole possess a wide range of modes of reproduction. Nematodes as a whole possess a wide range of modes of reproduction. Some nematodes, specifically Some nematodes, specifically HeterorhabditisHeterorhabditis spp., undergo a process called : birth spp., undergo a process called : birth causing maternal death. Some nematodes, like other animals (for example causing maternal death. Some nematodes, like other animals (for example segmented worms), are hermaphroditic. The hermaphroditic nematode keeps its self-segmented worms), are hermaphroditic. The hermaphroditic nematode keeps its self-fertilized eggs inside its uterus until they hatch. The juvenile nematodes will then fertilized eggs inside its uterus until they hatch. The juvenile nematodes will then ingest the parent nematode. This process is significantly promoted in environments ingest the parent nematode. This process is significantly promoted in environments with a low or reducing food supply. The nematode model species with a low or reducing food supply. The nematode model species Caenorhabditis Caenorhabditis eleganselegans and and C. briggsaeC. briggsae exhibit androdioecy, which is very rare amongst animals. exhibit androdioecy, which is very rare amongst animals. The single genus The single genus MeloidogyneMeloidogyne (root-knot nematodes) exhibit a range of reproductive (root-knot nematodes) exhibit a range of reproductive modes including sexuality (amphimixis), meiotic parthenogenesis () and mitotic modes including sexuality (amphimixis), meiotic parthenogenesis () and mitotic parthenogenesis (apomixis).parthenogenesis (apomixis).

Several Member NemathodeSeveral Member Nemathode- Ascaris lumbricoides (rounds worm)- Ascaris lumbricoides (rounds worm) AscariasisAscariasis

AscariasisAscariasis is a human disease is a human disease caused by the parasitic roundworm caused by the parasitic roundworm Ascaris Ascaris lumbricoideslumbricoides. Perhaps as many as one quarter . Perhaps as many as one quarter of the world's people are infected, and of the world's people are infected, and ascariasis is particularly prevalent in tropical ascariasis is particularly prevalent in tropical regions and in areas of poor hygiene. Other regions and in areas of poor hygiene. Other species of the genus species of the genus AscarisAscaris are parasitic and are parasitic and can cause disease in domestic animals.can cause disease in domestic animals.

Infection occurs through ingestion Infection occurs through ingestion of food contaminated with feces containing of food contaminated with feces containing AscarisAscaris eggs. The larvae hatch, burrow through eggs. The larvae hatch, burrow through the intestine, reach the lungs, and finally the intestine, reach the lungs, and finally migrate up the respiratory tract. From there migrate up the respiratory tract. From there they are then reswallowed and mature in the they are then reswallowed and mature in the intestine, growing up to 30 cm (12 in.) in length intestine, growing up to 30 cm (12 in.) in length and anchoring themselves to the intestinal wall.and anchoring themselves to the intestinal wall.

Infections are usually Infections are usually asymptomatic, especially if the number of asymptomatic, especially if the number of worms is small. They may however be worms is small. They may however be accompanied by inflammation, fever, and accompanied by inflammation, fever, and diarrhea, and serious problems may develop if diarrhea, and serious problems may develop if the worms migrate to other parts of the body.the worms migrate to other parts of the body.

males are smaller and have hooks

Life cycleLife cycleFirst appearance of eggs in First appearance of eggs in

stools is 60-70 days. In larval ascariasis, stools is 60-70 days. In larval ascariasis, symptoms occur 4-16 days after infection. symptoms occur 4-16 days after infection. The final symptoms are gastrointestinal The final symptoms are gastrointestinal discomfort, colic and vomiting, fever, and discomfort, colic and vomiting, fever, and observation of live worms in stools. Some observation of live worms in stools. Some patients may have pulmonary symptoms or patients may have pulmonary symptoms or neurological disorders during migration of neurological disorders during migration of the larvae. However there are generally few the larvae. However there are generally few or no symptoms. A bolus of worms may or no symptoms. A bolus of worms may obstruct the intestine; migrating larvae may obstruct the intestine; migrating larvae may cause pneumonitis and eosinophilia. cause pneumonitis and eosinophilia.

Life cycleLife cycleascaris lumbricodesascaris lumbricodes

Adult worms (1) live in the lumen of the small intestine. A female may produce approximately 200,000 eggs per day, which are passed with the feces (2). Unfertilized eggs may be ingested but are not infective. Fertile eggs embryonate and become infective after 18 days to several weeks (3), depending on the environmental conditions (optimum: moist, warm, shaded soil). After infective eggs are swallowed (4), the larvae hatch (5), invade the intestinal mucosa, and are carried via the portal, then systemic circulation and/or lymphatics to the lungs . The larvae mature further in the lungs (6) (10 to 14 days), penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed (7). Upon reaching the small intestine, they develop into adult worms (8). Between 2 and 3 months are required from ingestion of the infective eggs to oviposition by the adult female. Adult worms can live 1 to 2 years.

SourceSourceThe source of transmission is The source of transmission is

from soil and vegetation on which fecal from soil and vegetation on which fecal matter containing eggs has been deposited. matter containing eggs has been deposited. Ingestion of infective eggs from soil Ingestion of infective eggs from soil contaminated with human feces or contaminated with human feces or transmission and contaminated vegetables transmission and contaminated vegetables and water is the primary route of infection. and water is the primary route of infection. Intimate contact with pets which have been Intimate contact with pets which have been in contact with contaminated soil may result in contact with contaminated soil may result in infection, while pets which are infested in infection, while pets which are infested themselves by a different type of themselves by a different type of roundworm can cause infection with that roundworm can cause infection with that type of worm (Toxocara canis, etc) as type of worm (Toxocara canis, etc) as occasionally occurs with groomers.occasionally occurs with groomers.

Transmission from human to Transmission from human to human by direct contact is impossible.human by direct contact is impossible.

SymptomsSymptomsPatients can remain Patients can remain

asymptomatic for very long periods of time. asymptomatic for very long periods of time. As larval stages travel through the body, As larval stages travel through the body, they may cause visceral damage, peritonitis they may cause visceral damage, peritonitis and inflammation, enlargement of the liver and inflammation, enlargement of the liver or spleen, toxicity, and pneumonia. A heavy or spleen, toxicity, and pneumonia. A heavy worm infestation may cause nutritional worm infestation may cause nutritional deficiency; other complications, sometimes deficiency; other complications, sometimes fatal, include obstruction of the bowel by a fatal, include obstruction of the bowel by a bolus of worms (observed particularly in bolus of worms (observed particularly in children) and obstruction of the bile or children) and obstruction of the bile or pancreatic duct. More than 796 pancreatic duct. More than 796 Ascaris Ascaris lumbricoideslumbricoides worms weighing 550 g [19 worms weighing 550 g [19 ounces] were recovered at autopsy from a ounces] were recovered at autopsy from a 2-year-old South African girl. The worms 2-year-old South African girl. The worms had caused torsion and gangrene of the had caused torsion and gangrene of the ileum, which was interpreted as the cause ileum, which was interpreted as the cause of death.of death.

AscarisAscaris takes most of its takes most of its nutrients from the partially digested host nutrients from the partially digested host food in the intestine. There is limited food in the intestine. There is limited evidence that it can also pierce the intestinal evidence that it can also pierce the intestinal mucous membrane and feed on blood, but mucous membrane and feed on blood, but this is not its usual source of nutrition. As a this is not its usual source of nutrition. As a result, result, AscarisAscaris infection does not produce infection does not produce the anemia associated with some other the anemia associated with some other roundworm infections.roundworm infections.

PreventionPreventionPrevention includes: use of Prevention includes: use of toilettoilet facilities; safe excreta disposal; protection of facilities; safe excreta disposal; protection of

food from dirt and soil; thorough washing of produce; and hand washing.food from dirt and soil; thorough washing of produce; and hand washing.Food dropped on the floor should never be eaten without washing or cooking, Food dropped on the floor should never be eaten without washing or cooking,

particularly in endemic areas. Fruits and vegetables should always be washed thoroughly particularly in endemic areas. Fruits and vegetables should always be washed thoroughly before consumption.before consumption.

TreatmentTreatmentPharmaceutical drugs that are used to kill roundworms are called Pharmaceutical drugs that are used to kill roundworms are called ascaricidesascaricides and and

include:include: MebendazoleMebendazole (Vermox) (C16H13N3O2). Causes slow immobilization and death of the worms (Vermox) (C16H13N3O2). Causes slow immobilization and death of the worms

by selectively and irreversibly blocking uptake of glucose and other nutrients in susceptible by selectively and irreversibly blocking uptake of glucose and other nutrients in susceptible adult intestine where helminths dwell. Oral dosage is 100 mg 12 hourly for 3 days. adult intestine where helminths dwell. Oral dosage is 100 mg 12 hourly for 3 days.

PiperazinePiperazine (C4H10N2.C6H10O4). A flaccid paralyzing agent that causes a blocking response (C4H10N2.C6H10O4). A flaccid paralyzing agent that causes a blocking response of ascaris muscle to acetylcholine. The narcotizing effect immobilizes the worm, which of ascaris muscle to acetylcholine. The narcotizing effect immobilizes the worm, which prevents migration when treatment is accomplished with weak drugs such as thiabendazole. If prevents migration when treatment is accomplished with weak drugs such as thiabendazole. If used by itself it causes the worm to be passed out in the feces. Dosage is 75 mg/kg (max 3.5 used by itself it causes the worm to be passed out in the feces. Dosage is 75 mg/kg (max 3.5 g) as a single oral dose. g) as a single oral dose.

Pyrantel pamoatePyrantel pamoate (Antiminth, Pin-Rid, Pin-X) (C11H14N2S.C23H16O6) Depolarizes (Antiminth, Pin-Rid, Pin-X) (C11H14N2S.C23H16O6) Depolarizes ganglionic block of nicotinic neuromuscular transmission, resulting in spastic paralysis of the ganglionic block of nicotinic neuromuscular transmission, resulting in spastic paralysis of the worm. Spastic (tetanic) paralyzing agents, in particular pyrantel pamoate, may induce worm. Spastic (tetanic) paralyzing agents, in particular pyrantel pamoate, may induce complete intestinal obstruction in a heavy worm load. Dosage is 11 mg/kg not to exceed 1 g complete intestinal obstruction in a heavy worm load. Dosage is 11 mg/kg not to exceed 1 g as a single dose. as a single dose.

AlbendazoleAlbendazole (C12H15N3O2S) A broad-spectrum antihelminthic agent that decreases (C12H15N3O2S) A broad-spectrum antihelminthic agent that decreases ATPATP production in the worm, causing energy depletion, immobilization, and finally death. Dosage is production in the worm, causing energy depletion, immobilization, and finally death. Dosage is 400 mg given as single oral dose (contraindicated during pregnancy and children under 2 400 mg given as single oral dose (contraindicated during pregnancy and children under 2 years). years).

ThiabendazoleThiabendazole. This may cause migration of the worm into the . This may cause migration of the worm into the esophagusesophagus, so it is usually , so it is usually combined with piperazine. combined with piperazine.

HexylresorcinolHexylresorcinol effective in single dose effective in single doseSantoninSantonin, more toxic than , more toxic than hexylresorcinolhexylresorcinol, , Oil of chenopodiumOil of chenopodium, more toxic than , more toxic than hexylresorcinolhexylresorcinol, dition , dition Also, corticosteroids can treat some of the symptoms, such as inflammation.Also, corticosteroids can treat some of the symptoms, such as inflammation.

Genus and SpeciesGenus and Species Ascaris lumbricoidesAscaris lumbricoides

Common NameCommon Name Giant Intestinal RoundwormGiant Intestinal Roundworm

Etiologic Agent of:Etiologic Agent of: AscariasisAscariasis

Infective stageInfective stage Embryonated EggEmbryonated Egg

Definitive HostDefinitive Host ManMan

Portal of EntryPortal of Entry MouthMouth

Mode of TransmissionMode of Transmission Ingestion of Embryonated egg through contaminated food or waterIngestion of Embryonated egg through contaminated food or water

HabitatHabitat Small IntestineSmall Intestine

Pathogenic StagePathogenic Stage Adult, LarvaAdult, Larva

Mode of AttachmentMode of Attachment Retention in the mucosal folds using pressureRetention in the mucosal folds using pressure

Mode of NutritionMode of Nutrition Feeding of ChymeFeeding of Chyme

PathogenesisPathogenesis Larva – pneumonitis, ; Adult – Obstruction, Liver abscess, Appendicitis. With Blood-Lung Larva – pneumonitis, ; Adult – Obstruction, Liver abscess, Appendicitis. With Blood-Lung Phase along with Hookworms and Strongyloides stercoralis.Phase along with Hookworms and Strongyloides stercoralis.

Laboratory diagnosisLaboratory diagnosis Concentration methods and Direct Fecal SmearConcentration methods and Direct Fecal Smear

TreatmentTreatment Albendazole, Mebendazole, or Pyrantel pamoateAlbendazole, Mebendazole, or Pyrantel pamoate

Diagnostic Feature - AdultDiagnostic Feature - Adult Female - prominent genital girdleFemale - prominent genital girdle

Diagnostic Feature - EggDiagnostic Feature - Egg Coarse mammilated albuminous coatingCoarse mammilated albuminous coating

- Quick facts- Quick facts

2. 2. Wuchereria bancrofti (filaria)Wuchereria bancrofti (filaria)

Wuchereria bancroftiWuchereria bancrofti or or FilariaFilaria, is a , is a parasitic filarial nematode wormparasitic filarial nematode worm spread by a spread by a mosquito vectormosquito vector. It is one of the . It is one of the three parasites that cause three parasites that cause lymphatic lymphatic filariasisfilariasis. Elephantiasis can result if the . Elephantiasis can result if the infection is left untreated. infection is left untreated. Limited treatment Limited treatment modalities exist and no vaccines have been modalities exist and no vaccines have been developeddeveloped..

W. bancroftiW. bancrofti carry out their life carry out their life cycle in cycle in two hosttwo host. Human beings serve as . Human beings serve as the the definitive hostdefinitive host and and mosquitoesmosquitoes as their as their intermediate hostsintermediate hosts. The adult parasites . The adult parasites reside in the lymphatics. They are reside in the lymphatics. They are viviparousviviparous. The first stage larvae are known . The first stage larvae are known as as microfilariaemicrofilariae. The microfilaria are present . The microfilaria are present in the in the circulationcirculation. The microfilaria migrate . The microfilaria migrate between the deep and the peripheral between the deep and the peripheral circulation. During the day they are present circulation. During the day they are present in the deep veins and during the night the in the deep veins and during the night the migrate to the peripheral circulation. Next, migrate to the peripheral circulation. Next, the worm is transferred into a the worm is transferred into a vectorvector; the; the

most common vectors are the mosquito species: most common vectors are the mosquito species: CulexCulex, , AnophelesAnopheles, , MansoniaMansonia, and , and AedesAedes. Inside . Inside their second host, it matures into motile larvae. their second host, it matures into motile larvae. When its current host feeds, and it is egested into When its current host feeds, and it is egested into the blood stream of its new human host. The the blood stream of its new human host. The larvae moves to the lymph nodes, predominantly larvae moves to the lymph nodes, predominantly in the legs and genital area, and develops into in the legs and genital area, and develops into adult worm over the course of a year. By this time, adult worm over the course of a year. By this time, an adult female can produce microfilariae herself.an adult female can produce microfilariae herself.

• Wuchereria bancrofti

- - PathogenesisPathogenesis

The pathogenesis of W. The pathogenesis of W. bancroftibancrofti infection is dependent on the infection is dependent on the host's immune system and inflammatory host's immune system and inflammatory responses. After infection, the worms will responses. After infection, the worms will mature within 6-8 months and then the mature within 6-8 months and then the release of the microfilariae will begin. These release of the microfilariae will begin. These microfilariae worms can be released for up microfilariae worms can be released for up to ten years.to ten years.1. Asymptomatic Phase1. Asymptomatic Phase -Usually consists -Usually consists of high microfilaremia infection and of high microfilaremia infection and individuals show no symptoms of being individuals show no symptoms of being infected. This occurs due to the cytokine IL-infected. This occurs due to the cytokine IL-4 suppressing the activity of TH1 cells in our 4 suppressing the activity of TH1 cells in our immune system. This can occur for years immune system. This can occur for years until the inflammatory reaction rise again. until the inflammatory reaction rise again.

2. Inflammatory (Acute) Phase2. Inflammatory (Acute) Phase -The -The antigens from the female adult worms elicit antigens from the female adult worms elicit inflammatory responses. The worms in the inflammatory responses. The worms in the lymph channels disrupt the flow of the lymph channels disrupt the flow of the lymph causing lymph causing lymphedemalymphedema. The individual . The individual will exhibit fever, chills, skin infections, will exhibit fever, chills, skin infections, painful lymph nodes, and tender skin of the painful lymph nodes, and tender skin of the lymphedematous extremity. These lymphedematous extremity. These symptoms often lessen after 5-7 days. symptoms often lessen after 5-7 days. Other symptoms that may occur include: Other symptoms that may occur include: orchitisorchitis-inflammation of the testes, which is -inflammation of the testes, which is accompanied by painful immediate accompanied by painful immediate enlargement and enlargement and epididymitisepididymitis-which is the -which is the inflammation of the spermatic cord.inflammation of the spermatic cord.3. Obstructive (Chronic) Phase3. Obstructive (Chronic) Phase -marked -marked by by lymph variceslymph varices, , lymph scrotumlymph scrotum, , hydrocelehydrocele, , chyluriachyluria(lymph in urine), and (lymph in urine), and elephantiasiselephantiasis. Microfilariae are not . Microfilariae are not normally present in this phase. A key normally present in this phase. A key feature of this phase is scar formation from feature of this phase is scar formation from affected tissue areas. Other features include affected tissue areas. Other features include thickening of the skin and elephantiasis thickening of the skin and elephantiasis which develops gradually with the attack of which develops gradually with the attack of the lymphatic system. Elephantiasis affect the lymphatic system. Elephantiasis affect men mainly on the legs, arms, and scrotum. men mainly on the legs, arms, and scrotum. In women, the legs and arms are affected.In women, the legs and arms are affected.

Life cycle Life cycle

Treatment/ControlTreatment/ControlThe parasite's severe symptoms can be avoided by cleansing the skin, surgery, or The parasite's severe symptoms can be avoided by cleansing the skin, surgery, or

the use of therapeutic drugs, such as Diethylcarbamazine(DEC), ivermectin, or albendazole. The the use of therapeutic drugs, such as Diethylcarbamazine(DEC), ivermectin, or albendazole. The drug of choice however, is DEC, which can eliminate the microfilariae from the blood and also kill drug of choice however, is DEC, which can eliminate the microfilariae from the blood and also kill the adult worms with a dosage of 6 mg/kg semiannually or annually. A treatment that includes the adult worms with a dosage of 6 mg/kg semiannually or annually. A treatment that includes ivermectin with DEC or albendazole is more effective than each drug alone. Protection is similar ivermectin with DEC or albendazole is more effective than each drug alone. Protection is similar to that of other mosquito spread illnesses; one can use barriers both physical (a mosquito net), to that of other mosquito spread illnesses; one can use barriers both physical (a mosquito net), chemical (insect repellent), or mass chemotherapy′ as a method to control the spreading of the chemical (insect repellent), or mass chemotherapy′ as a method to control the spreading of the disease.disease.

3. 3. Necator / Ancylostoma duodenale (hookworm)Necator / Ancylostoma duodenale (hookworm)

HookwormHookworm is a parasitic nematode worm is a parasitic nematode worm that lives in the small intestine of its host, that lives in the small intestine of its host, which may be a mammal such as a dog, which may be a mammal such as a dog, cat, or human. Two species of hookworms cat, or human. Two species of hookworms commonly infect humans, commonly infect humans, Ancylostoma Ancylostoma duodenaleduodenale and and Necator americanusNecator americanus. . Hookworms are also bilateral, meaning that Hookworms are also bilateral, meaning that if cut in half, the worm would be the exact if cut in half, the worm would be the exact same on each side. same on each side. Necator americanusNecator americanus predominates in the Americas, Sub-predominates in the Americas, Sub-Saharan Africa, Southeast Asia, Saharan Africa, Southeast Asia,

China, and Indonesia, while China, and Indonesia, while A. duodenaleA. duodenale predominates in the Middle East, North Africa, predominates in the Middle East, North Africa, India and (formerly) in southern Europe. The India and (formerly) in southern Europe. The Ancylostoma brazilienseAncylostoma braziliense and and A. tubaeformeA. tubaeforme species infect cats, while species infect cats, while A. caninumA. caninum infects infects dogs. dogs. Uncinaria stenocephalaUncinaria stenocephala infects both dogs infects both dogs and cats.Hookworms are much smaller than and cats.Hookworms are much smaller than the large roundworm, the large roundworm, Ascaris lumbricoidesAscaris lumbricoides, , and the complications of tissue migration and and the complications of tissue migration and mechanical obstruction so frequently observed mechanical obstruction so frequently observed with roundworm infestation are less frequent in with roundworm infestation are less frequent in hookworm infestation. The most significant risk hookworm infestation. The most significant risk of hookworm infection is anemia, secondary to of hookworm infection is anemia, secondary to loss of iron (and protein) in the gut. The worms loss of iron (and protein) in the gut. The worms suck blood voraciously and damage the suck blood voraciously and damage the mucosa. However, the blood loss in the stools mucosa. However, the blood loss in the stools is occult blood loss (not visibly apparent).is occult blood loss (not visibly apparent).

Infection of the host is by the larvae, not the Infection of the host is by the larvae, not the eggs. While eggs. While A. duodenaleA. duodenale can be ingested, can be ingested, the usual method of infection is through the the usual method of infection is through the skin; this is commonly caused by walking skin; this is commonly caused by walking barefoot through areas contaminated with barefoot through areas contaminated with fecal matter. The larvae are able to penetrate fecal matter. The larvae are able to penetrate the skin of the foot, and once inside the body, the skin of the foot, and once inside the body, they migrate through the vascular system to they migrate through the vascular system to the lungs, and from there up the trachea, and the lungs, and from there up the trachea, and are swallowed. They then pass down the are swallowed. They then pass down the esophagus and enter the digestive system, esophagus and enter the digestive system, finishing their journey in the intestine, where finishing their journey in the intestine, where the larvae mature into adult worms.the larvae mature into adult worms.

Once in the host gut, Once in the host gut, NecatorNecator tends to cause tends to cause a prolonged infection, generally 1–5 years a prolonged infection, generally 1–5 years (many die within a year or two of infecting), (many die within a year or two of infecting), though some adult worms have been though some adult worms have been recorded to live for 15 years or more. On the recorded to live for 15 years or more. On the other hand, other hand, AncylostomaAncylostoma adults are short adults are short lived, surviving on average for only about 6 lived, surviving on average for only about 6 months. However, infection can be prolonged months. However, infection can be prolonged because dormant larvae can be "recruited" because dormant larvae can be "recruited" sequentially from tissue "stores" over many sequentially from tissue "stores" over many years, to replace expired adult worms. This years, to replace expired adult worms. This can give rise to seasonal fluctuations in can give rise to seasonal fluctuations in infection prevalence and intensity (apart from infection prevalence and intensity (apart from normal seasonal variations in transmission). .normal seasonal variations in transmission). .

They mate inside the host, females laying up They mate inside the host, females laying up to 30,000 eggs per day and some 18 to 54 to 30,000 eggs per day and some 18 to 54 million eggs during their lifetime, which pass million eggs during their lifetime, which pass out in feces. Because it takes 5–7 weeks for out in feces. Because it takes 5–7 weeks for adult worms to mature, mate and produce adult worms to mature, mate and produce eggs, in the early stages of very heavy eggs, in the early stages of very heavy infection, acute symptoms might occur infection, acute symptoms might occur without any eggs being detected in the without any eggs being detected in the patient's feces.patient's feces.

Life cycleLife cycle

SymptomsSymptomsThere are no specific symptoms There are no specific symptoms

or signs of hookworm infection. As or signs of hookworm infection. As mentioned above, they arise from a mentioned above, they arise from a combination of intestinal inflammation and combination of intestinal inflammation and progressive iron/protein-deficiency anemia. progressive iron/protein-deficiency anemia. Larval invasion of the skin might give rise to Larval invasion of the skin might give rise to intense, local itching, usually on the foot or intense, local itching, usually on the foot or lower leg, which can be followed by lesions lower leg, which can be followed by lesions that look like insect bites, can blister, and that look like insect bites, can blister, and last for a week or more. Animal hookworm last for a week or more. Animal hookworm larvae on penetrating humans may produce larvae on penetrating humans may produce a creeping eruption called cutaneous larva a creeping eruption called cutaneous larva migrans. The larvae migrate in tortuous migrans. The larvae migrate in tortuous tunnels in between stratum germinativum tunnels in between stratum germinativum and stratum corneum of the skin, causing and stratum corneum of the skin, causing serpigenous vesicular lesions. With serpigenous vesicular lesions. With advancing movement of the larvae, the rear advancing movement of the larvae, the rear portions of the lesions become dry and portions of the lesions become dry and crusty. The lesions are typically intensely crusty. The lesions are typically intensely pruritic. Coughing, chest pain, wheezing, pruritic. Coughing, chest pain, wheezing, and fever will sometimes be experienced by and fever will sometimes be experienced by people who have been exposed to very people who have been exposed to very large numbers of larvae. Epigastric pains, large numbers of larvae. Epigastric pains, indigestion, nausea vomiting, constipation, indigestion, nausea vomiting, constipation, and diarrhea can occur early or in later and diarrhea can occur early or in later stages as well, although gastrointestional stages as well, although gastrointestional symptoms tend to improve with time. Signs symptoms tend to improve with time. Signs of advanced severe infection are those of of advanced severe infection are those of anemia and protein deficiency, including anemia and protein deficiency, including emaciation, cardiac failure and abdominal emaciation, cardiac failure and abdominal distension with ascites.distension with ascites.

PreventionPreventionThe infective larvae develop and The infective larvae develop and

survive in an environment of damp dirt, survive in an environment of damp dirt, particularly sandy and loamy soil. They particularly sandy and loamy soil. They cannot survive in clay or muck. The main cannot survive in clay or muck. The main lines of precaution are those dictated by lines of precaution are those dictated by sanitary science:sanitary science:

Do not defecate outside latrines, toilets etc. Do not defecate outside latrines, toilets etc. Do not use human excrement or raw Do not use human excrement or raw

sewage as manure/fertilizer in agriculture sewage as manure/fertilizer in agriculture Deworm pet dogs — canine and feline Deworm pet dogs — canine and feline

hookworms rarely develop to adulthood in hookworms rarely develop to adulthood in humans (humans (Ancylostoma caninumAncylostoma caninum, the , the common dog hookworm, occasionally common dog hookworm, occasionally develops into an adult to cause eosinophilic develops into an adult to cause eosinophilic enteritis in people), but their invasive larvae enteritis in people), but their invasive larvae can cause an itchy rash called cutaneous can cause an itchy rash called cutaneous larva migranslarva migrans

TreatmentTreatment The hookworm can be treated with local The hookworm can be treated with local

cryotherapy when it is still in the skin.cryotherapy when it is still in the skin. Albendazole is effective both in the Albendazole is effective both in the

intestinal stage and during the stage the intestinal stage and during the stage the parasite is still migrating under the skin.parasite is still migrating under the skin.

In case of anemia, iron supplementation can In case of anemia, iron supplementation can cause relief symptoms of iron deficiency cause relief symptoms of iron deficiency anemia. However, as red blood cell levels anemia. However, as red blood cell levels are restored, shortage of other essentials are restored, shortage of other essentials such as folic acid or vitamin B12 may such as folic acid or vitamin B12 may develop, so this might also be develop, so this might also be supplemented.supplemented.

The most common treatment for Hookworm The most common treatment for Hookworm are Benzimidazoles (BZAs), are Benzimidazoles (BZAs),

Genus and Species Necator americanus

Ancylostoma duodenale

Common Name New world hookworm, American murderer Old world hookworm

Etiologic Agent of: Necatoriasis, Uncinariasis Ancylostomiasis,

Wakana disease

Infective stage Filariform larva Filariform larva

Definitive Host Man Man

Portal of Entry Usually via skin penetration rather than

ingestion

Usually via ingestion rather than skin

penetration

Mode of Transmission Skin > Mouth Mouth > Skin

Habitat Small Intestine Small Intestine

Pathogenic Stage Larva Larva

Maturation time in host (days) 49-56 53

Mode of Attachment Oral attachment to mucosa by sucking Same

Mode of Nutrition Sucking and Ingesting of blood Same Same

Treatment Albendazole, Mebendazole, or Pyrantel

Pamoate Same

Length of adult hookworm (mm)

5-9 for males; 9-11 for females 8-11 for males; 10-13 for

females

Shape

Head curved opposite to curvature of body, giving a hooked appearance to

anterior end

Head continuous in same direction as

the body

Egg output per female worm per

day 5,000-10,000 10,000-25,000

Blood loss per worm per day (ml) 0.03 0.15-0.23

4. 4. Enterobius vermicularis (pinworm)Enterobius vermicularis (pinworm)

The The pinwormpinworm (Genus (Genus EnterobiusEnterobius), also ), also known as known as threadwormthreadworm or or seat wormseat worm, is a , is a common human intestinal parasite, common human intestinal parasite, especially in children. The medical condition especially in children. The medical condition associated with pinworm infestation is associated with pinworm infestation is known as known as enterobiasisenterobiasis , or sometimes , or sometimes oxyuriasisoxyuriasis. .

ReproductionReproductionAfter mating, the male dies. The female After mating, the male dies. The female migrates to the anus and emerges, usually migrates to the anus and emerges, usually during the night, to deposit about 10,000 to during the night, to deposit about 10,000 to 20,000 eggs in the perianal area (around 20,000 eggs in the perianal area (around the anus). She then secretes a substance the anus). She then secretes a substance which causes a very strong itching which causes a very strong itching sensation, inciting the host to scratch the sensation, inciting the host to scratch the area and thus transfer some of the eggs to area and thus transfer some of the eggs to the fingers. Eggs can also be transferred to the fingers. Eggs can also be transferred to cloth, toys, and the bathtub. Once ingested cloth, toys, and the bathtub. Once ingested orally, the larvae hatch in the small orally, the larvae hatch in the small intestine, specifically the duodenum, and intestine, specifically the duodenum, and migrate back to the large intestine where migrate back to the large intestine where they mature. Maturity is reached in 30–45 they mature. Maturity is reached in 30–45 days. The eggs can survive for 2 to 3 weeks days. The eggs can survive for 2 to 3 weeks on their own outside of the human body. In on their own outside of the human body. In some cases, the larvae will hatch in the some cases, the larvae will hatch in the peri-anal area and travel back inside the peri-anal area and travel back inside the anus, up the rectum, and back into the anus, up the rectum, and back into the intestines where they mature intestines where they mature

EffectsEffectsExcept for itching pinworm Except for itching pinworm

infestation does not usually cause any infestation does not usually cause any damage to the body. Sleep disturbance may damage to the body. Sleep disturbance may arise from the itching or crawling arise from the itching or crawling sensations. Some case reports suggest that sensations. Some case reports suggest that severe infestation may be associated with severe infestation may be associated with an increased risk for appendicitis. There is an increased risk for appendicitis. There is also some evidence of an association also some evidence of an association between enterobiasis and diminished zinc between enterobiasis and diminished zinc levels.levels.

TreatmentTreatmentAnti-pinworm drugs such as Anti-pinworm drugs such as

albendazole (Albenza), mebendazole albendazole (Albenza), mebendazole (Vermox, OVEX), Piperazine and pyrantel (Vermox, OVEX), Piperazine and pyrantel pamoate (Pin-X, Reese's Pinworm pamoate (Pin-X, Reese's Pinworm Medication) are commonly used to treat Medication) are commonly used to treat pinworms as well as ascaris lumbricoides pinworms as well as ascaris lumbricoides (the roundworm). It is not a necessity to visit (the roundworm). It is not a necessity to visit a doctor to get these drugs, as pyrantel a doctor to get these drugs, as pyrantel pamoate (Pin-X) is available as an over-the-pamoate (Pin-X) is available as an over-the-counter medication (albendazole and counter medication (albendazole and mebendazole are prescription in the US); mebendazole are prescription in the US); ask a pharmacist for medicines to treat ask a pharmacist for medicines to treat pinworms (or threadworms as they are pinworms (or threadworms as they are known in the UK). These medicines kill the known in the UK). These medicines kill the pinworms 95% of the time, but do not kill the pinworms 95% of the time, but do not kill the eggs. The person being treated may have to eggs. The person being treated may have to return after a time of two weeks to be re-return after a time of two weeks to be re-treated. Another precaution is to wash the treated. Another precaution is to wash the hands before eating (to prevent any hands before eating (to prevent any pinworm eggs under fingernails from being pinworm eggs under fingernails from being ingested) and to wash any area or clothes ingested) and to wash any area or clothes which have touched or been in the vicinity of which have touched or been in the vicinity of the infected areasthe infected areas

5. Trichinella spiralis5. Trichinella spiralis

The species The species Trichinella spiralisTrichinella spiralis is an is an nematode parasite, occurring in rats, pigs, nematode parasite, occurring in rats, pigs, and humans, and is responsible for the and humans, and is responsible for the disease trichinosis. It is sometimes referred disease trichinosis. It is sometimes referred to as the "pork worm" due to it being found to as the "pork worm" due to it being found commonly in pork or rat products that are commonly in pork or rat products that are undercooked undercooked

SymptomsSymptomsThe first symptoms may appear between 12 The first symptoms may appear between 12 hours and two days after ingestion of hours and two days after ingestion of infected meat. The migration of worms in infected meat. The migration of worms in the intestinal epithelium can cause the intestinal epithelium can cause traumatic damage to the host tissue and the traumatic damage to the host tissue and the waste products they excrete can provoke an waste products they excrete can provoke an immunological reaction. The resulting immunological reaction. The resulting inflammation can cause symptoms such as inflammation can cause symptoms such as nausea, vomiting, sweating and diarrhea. nausea, vomiting, sweating and diarrhea. Five to seven days after the appearance of Five to seven days after the appearance of symptoms facial edema and fever may symptoms facial edema and fever may occur. After 10 days intense muscular pain, occur. After 10 days intense muscular pain, difficulty breathing, weakening of pulse and difficulty breathing, weakening of pulse and blood pressure, heart damage and various blood pressure, heart damage and various nervous disorders may occur, eventually nervous disorders may occur, eventually leading to death due to heart failure, leading to death due to heart failure, respiratory complications or kidney respiratory complications or kidney malfunctionmalfunction

Life cycleLife cycleLarvae encysted in the muscles remain Larvae encysted in the muscles remain viable for some time. When the muscle viable for some time. When the muscle tissue is eaten by a human, the cysts are tissue is eaten by a human, the cysts are digested in the stomach; the released larvae digested in the stomach; the released larvae migrate to the intestine to begin a new life migrate to the intestine to begin a new life cycle. Female trichina worms live about six cycle. Female trichina worms live about six weeks and in that time may release larvae. weeks and in that time may release larvae. The migration and encystment of larvae can The migration and encystment of larvae can cause fever, pain, and even death because cause fever, pain, and even death because of their potential to eat living tissue. One of of their potential to eat living tissue. One of the classic signs of the classic signs of Trichinella spiralisTrichinella spiralis infection is a combination of splinter infection is a combination of splinter hemorrhages (not to be confused with those hemorrhages (not to be confused with those of bacterial endocarditis) and periorbital of bacterial endocarditis) and periorbital edema (eye swelling). Trichina are edema (eye swelling). Trichina are classified in the phylum Nematoda, which classified in the phylum Nematoda, which includes Caenorhabditis elegans, an includes Caenorhabditis elegans, an important scientific model organism for important scientific model organism for studying genetics behind various topics studying genetics behind various topics such as development, neuroscience, such as development, neuroscience, disease, and aging.disease, and aging.

Diagnosis and treatmentDiagnosis and treatment

Muscle biopsy is used for trichinosis detection. Several immunodiagnostic tests are also Muscle biopsy is used for trichinosis detection. Several immunodiagnostic tests are also available. There are currently no satisfactory treatments for trichinosis, however symptoms can available. There are currently no satisfactory treatments for trichinosis, however symptoms can be relieved by use of analgesics and corticosteroidsbe relieved by use of analgesics and corticosteroids

Benefit and lossBenefit and loss

BenefitBenefit

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LossLoss

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conclusionconclusion