MEDICAL ENTOMOLOGYSubjects :1. Medical Entomology (Introduction)2. Mosquitoes and flies3. Mites

ARTHROPODS

MEDICAL ENTOMOLOGY IntroductionDefinition: entomology Science that study insects (Entomon = Insecta) and other species belonging to Phylum Arthropoda, in relation to health, and its control

Medical entomology Study of vector, vector borne diseases and abnormalities caused by insectsMedical entomology Introduction

entomology Medik (Kedokteran) Ilmu yang mempelajari tentang vector, disease dan kelainan yang disebabkan oleh insectsVectorVector are mostly insects which carry and transmit disease agents from patient to healthy person; or from disease sources to uninfected food or drinks Medical entomology Introduction

ARTHROPODA - Divided into 5 classes I. Class Insecta --- Medically important insect : * Order Diptera * Order Anoplura * Order Hemiptera * Order Siphonaptera II. Class Arachnida III. Class Crustacea IV. Class Chilopoda V. Class Diplopoda

MEDICAL ENTOMOLOGY IntroductionPhylum Arthropoda Multicellular animal (metazoa)Symmetric, bilateralSegmented body Possess an exoskeletonAppendages : antennae, palpa etc.

MetamorphosisMorphological changes and development in the life cycle of ArthropodsTwo type metamorphosisComplete metamorphosisIncomplete metamorphosisMedical entomologyIntroduction

Complete Metamorphosis Marked changes and development in the morphology and biology (natural habitat, types of food, etc)Eggs - Larva - Nymphs - AdultsIncomplete Metamorphosis Eggs/ova - (Larva) - Pupa - AdultsMedical entomology Introduction

Insects may act as* Vector/transmitter of disease agents* As direct cause/etiology of disease or injuryRole as vector ROLE OF ARTHROPODS

Mode of transmissionTwo modes of transmission As mechanical vector As biological vectorROLE OF ARTHROPODS

Role as mechanical vectordisease agents do not develop or multiply inside the vectorExample : gastroenteritis agents in flies and cockroachTransmission occurs through the proboscis, legs, body, wings

ROLE AS BIOLOGICAL VECTOR

- Disease agents develop or multiply inside the vectorExample :Plasmodium sp. at Anopheles sp.Transmission occurs through the probocis

As biological vector, disease agents are transmitted by several modes:Propagative modeCyclico propagativeCyclico developmentalTransovarian/hereditary modeRoIe as vectorROLE OF ARTHROPODS

Cyclico propagative transmissionTransmission is preceded by growth and multiplication of disease agents inside the body of insect vectorExample : Plasmodium inside AnophelesPropagative transmissionTransmission is preceded by multiplication of disease agents inside the body of vectorExample : Multiplication of Pasteurella pestis inside the body of fleas, prior to transmission

Transovarian/hereditary transmissionTransmission through the next generation Example : Rickketsia tsutsugamushi inside the body of Trombicula ticks Cyclico developmental transmissionTransmission is preceded by development of parasites without multiplicationExample : Filarial worm inside the body of Culex mosquito, where small larva (pre larva) stage called microfilaria worm develop into rhabditiform (L-1) larva, and finally into filariform (L-2 or L-3) larva

Medical entomology ROLE OF ARTHROPODSRole as vectorAnopheles , vector of malariaIntroduction

Medical entomology Role of ArthropodsRole as the cause of diseaseDisease or injury may be caused by insects through various means :- Mechanical injury- Injection of poisonous substances- Allergies- Psychosis Introduction

Medical entomology Role of ArthropodsRole as the cause of diseaseMechanical causeBites - sting - piercing and bloodsucking - larval movementArthropods may act as :Endoparasites : larva of flies causing myiasisEctoparasites: headlouse Permanent parasites : fleasIntermittent parasites: mosquitoIntroduction

AllergiesDyspnea /asthma : caterpillar, butterflies PsychosisEntomophobiaA boy with allergy from mosquito biteInjection of Toxic substancePoison enters through :Direct contact (caterpillars), bites (spider), sting (scorpion), piercing (mosquito)Common symptoms :Itching, swelling, urticaria (mosquito, caterpillars)Hemolysis (scorpion)bleeding (bees)Nerve damage (scorpion)

Medical entomology Role of ArthropodsInsect as cause of injury and diseaseIntroduction

Centipedes

Life cycleMosquitoLife span: 2 weeksComplete Metamorphosis (eggs - larva - pupa - adults).Eggs laid on water surface :White 1-2 hours - Turns black 2-4 days - Larva ( stage I - IV) 6-8 days - Pupa 1-3 day - Adults male and female(Larva become pupa for Culex and Aedes in 6-8 days but for Mansonia in 3 weeks)

Medical importanceMosquito

Mosquito bites may cause urticaria, and dermatitisAs vector transmitter of many diseases :Example 1:Malaria (Plasmodium)Main vectors of malaria in Jawa and Bali : Anopheles sundaicus, A. aconitus, A. subpictus, A. maculatus, A. balabacensis, A. sinensis. Medical importanceMosquito

Medical importanceMosquitovector of disease : Example 3.

Yellow fever - by Yellow Fever virus Primary vectors : Aedes aegypti, Ae. simpsoniJapanese B. encephalitis and St. Louis encephalitis (by JBE and SLE virus)Primary vectors : Culex pipiens, C. tarsalis, Ae. togoiMedical importanceMosquitovector of disease : Example 4 & 5

Medical importanceMosquitoAedes aegypti , vector of dengue fever

Bloodsucking Flies Flies

Bloodsucking Flies Flies

Medical importanceThe bites may cause dermal papules, intense pain, itching, nausea, fever, malaiseAs vector of the following diseases :FliesPhlebotomus sp.

Medical importancePainful bite, causing itch and fever Act as vector of disease (as intermediate host of Filarial worm) :Culicoides grahami, and C. austeni, as vector of Acanthocheilonema perstansCulicoides grahami as vector of Dipetalonema streptocercaCulicoides furens and C. paraensis as vector of Mansonella ozzardiCulicoides sp.Flies

Culicoides sp.Flies

Medical importancevector Arfiican sleeping disease Trypanosoma gambiense, vector is Glossina palpalisTrypanosoma rhodesiense, vector is Glossina morsitansGlossina sp.

Glossina sp.

Stomoxys sp.Medical importancePainful bites; mostly on cattle and horses which may cause anemia Mechanical vector of :Trypanosoma evansi which causes a disease in animals called surra - Example: Stomoxys calcitrans

Stomoxys sp.

Non-biting Flies

Non-biting Flies

Medical importanceAdult flies may act as mechanical vector of many disease agents : protozoa, worm eggs, bacteria, virus.Larva stage may invade human tissue causing a disease called myiasisMusca domestica

Musca domestica

Definition: Infestation of human or animal tissue or organs by maggot (larva stage) of certain non-biting flies

This larva live from tissue, body liquid, or food from the hospes MYIASIS

Specific/ Obligatory MyiasisSemi-specific/Facultative Myiasis Accidental Myiasis MYIASIS Classification based on biological characteristics of larvae

Semi-specific/Facultative Myiasis Larva may adapt to living on human tissue, meat carcasses, dead tissue, or rotten vegetablesExample : Larva of WohlfahrtiaSpecific/Obligatory MyiasisLarva/maggot inhabit specific tissue of the host eggs laid on normal or damaged tissue (open wound)Example : Larva of Callitroga macellariaMyiasis

MYIASISAccidental myiasisEggs laid on food/drinks. Developing larva accidentally swallowedExample : Larva of Musca, Drosophila, Piophila

Clinical classification based on organ habitatMyiasis of the skinMyiasis of the nasopharinxMyiasis intestinalMyiasis urogenital Myiasis of the eyesMyiasis

Clinical classification based on organ habitatDermal Myiasis By larva of Wohlfahrtia vigil, Chrysomyia bezzianaNaso-pharyngeal Myiasis Larva of Chrysomyia bezziana (one case reported from Taiping District Hospital, Perak).Intestinal Myiasis Accidentally ingesting food contaminated with eggs/larva of fliesLarva of Musca domestica, Piophila caseiMyiasis

Urogenital Myiasis - Larva inhabits lumen of vaginaSymptom : pyuria, urethritis, cystitisCaused by larva of Musca and ChrysomyaOcular Myiasis Certain eye infection may produce secrete which attracts flies to lay eggs on the ocular tissue Example: myiasis by larva of Chrysomyia flyClinical classification based on organ habitat

TRANSMISSIONInfestations occur when the insects put their eggs on the injury skin or open abscess. Species that cause myasis, for example Passeromyia longicomis larvae. Species that cause myasis dermal only, for example Cordylobia anthropophage and Cordylobia hominis.

SYMPTOM : Depend on the location of the tissue or organ. Ophtalmomyasis : pain in the eye caused by iritation. Dermal Myasis : dermal iritation, pruritus.

Diagnosis For Ophtalmomyasis, irrigation of lacrimal gland until the parasite come out. One drop of cocaine for paralyzing the movement, then lifted by using tweezer (forceps ). Same as dermal myasis. Myasis intestinal : feces examination.

Diagnosis of Myiasis

Find and identify the larva stageIdentification of species by examining the posterior spiracle (very characteristic for each species)

Treatment Usually myasis is Self Limiting Disease But sometimes, we can do minor surgery with local anestesion. For intestinal myasis : helminthic drug and purge. We do not use insecticide ( larvicide ) because its harmful to body tissue.

Myiasis Larvae in necrotic tissue

MyiasisMaggot on skin at side of lesion

MITESIntroductionClassified under ordo Acarina Causing acariasisMedically most important mites :Family Sarcoptidae (Scabies mite)Family Trombiculidae

MITES Scabies , Sarcoptic mangeEtiology : Sarcoptes scabieiFamily SarcoptidaeOrder : AcarinaDisease : scabies, sarcoptic mangeEctoparasite, inhabit the skin creating tunnels under the stratum corneum where female lay eggsPredilection sites : thin skin folds (between fingers, armpit, wrist, genital fold)

Common among children and adults of poor personal hygiene Among inhabitants of prisons, orphanages, boarding houses and military barracks

Scabies MitesClinical symptomsNight itch caused by : Female activity of tunnel burrowing Host reaction against metabolic wastes Pruritus, vesicules and pustula along the tunnel Pustula is the result of bacterial secondary infection

MITESScabies Mites

mitesScabies MitesscabiesSource :A Colour Atlas of Clinical Parasitology. Tomio Yamaguchi.. Translation : Lesmana Padmasutra, dkk.

Scabies MitesClinical D/By finding specific skin infection in the area of predilectionsObserving patient scratching specific area of predilectionLaboratory D/Potassium Hydroxide (KOH) Test : Skin scraping from predilection area is placed on a glass slide, add one drop of 10% KOH, warm the slide, cover with slide cover glass, and examine under the microscope to find the adult mite or the eggs. Dark Ink Test : place a drop of ink on the suspected skin surface, press slightly to allow ink to enter the tunnel, rinse and observe the ink filled tunnels Diagnosis

Scabies MitesTherapy Old method: 2-4 Ointment (2 parts of salicylic acid and 4 parts of sulfur)Solutio benzyl benzoate 20-35%Any ointment containing gammexane (gamma-benzene-hexachloride) or lindaneOintment cream containing permethrine 5% (e.g. Scabimite, Scabex)

Additional measures: Clothing items and bed sheets are washed routinely with hot water to kill any mite eggs and nymphsPlace mattress and pillows under the sun Scabies Mites scabies

HOUSE DUST MITEGenus : Dermatophagoides Species : *Dermatophagoides farinae * Dermatophagoides pteronyssinus

Responsible for an allergic condition Known as House dust allergy

HOUSE DUST MITE - An important cause of nasal allergy and asthma especially in children - Generally found in mattresses, pillows, overstuffed furniture, rugs, floors or other protected places where people sleep or sit for long periods

HOUSE DUST MITE - Life cycle takes about a month - Adults live for one to three months - Feeding on a variety of foods including dog food, cereals, yeast and especially the scaling of the skin of humans and their pets. - Eggs are laid singly

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