practical parasitology collected and prepared by: wael al laithi
TRANSCRIPT
Practical Parasitology
Collected and prepared by:Wael Al Laithi
The Life Cycle of Giardia Lamblia
Giardia lamblia The cysts, are oval measuring from 11 to 14 µm in length and 7 to 10 µm in width. Four nuclei are usually visible along with axonemes, and median bodies. Often, the cyst will appear shrunken, pulling away from the cyst wall
Giardia lamblia The trophozoites are described as having a 'tear-drop' shape and are 18 µm long and 10 µm wide. The trophozoites contain two nuclei, four pair of flagella, two axonemes, and two curved bodies called the median bodies.
Entamoeba histolytica Life cycle
the cysts can survive days to weeks in the external environment and are responsible for transmission
Trophozoites passed in the stool are rapidly destroyed once outside the body
Entamoeba histolytica
CYST 10 – 15 µMtrophozoite15 to 20 µm.
cyst will have 1 to 4 nuclei. In addition, the peripheral chromatin is generally evenly distributed.
Nematoda
Ascaris Lumbricoidesz
Ascariasis is a disease caused by Ascaris Lumbricoides, an intestinal roundworm known as a nematode
Ascaris lumbricoides life cycle
Female 50 cm
Male 30 cm
Ascaris Fertilized, decorticated eggs
size 45 - 85 microns
Fertilized, corticated eggs Ascaris
Ascaris unfertilized or otherwise non-viable eggs
Egg size(infertile): 78 - 105 microns in length Both fertile and infertile ova can be corticated or smooth
The life cycle of Enterobius vermicularis
Female 8-13 mm
Male 2-5mm
Eggs of the human pinworm Enterobius vermicularis
Egg size 50-60 µm by 20-32 µm
Egg size: 52 - 58 microns
Rhabditiform larva length: 250 microns
Filariform larva: 550 microns
3 or 4 days to filariform 2-5
days
Strongyloides stercoralis life cycle
Rhabditiform larva of Strongyloides stercoralis. 100x
larvae hatch in 1 to 2 days.
after 5 to 10 days
infective larvae can survive 3 to 4 weeks in favorable environmental conditions
Hookworm Ancylostoma braziliense] [Ancylostoma caninum] [Ancylostoma duodenale] [Necator americanus]
Necator americanus : 5 to 11 millimetres , 90 percent of human hookworm infections that occur in tropical and subtropical regions of the world
A. braziliense, from 8 to 11 millimetres long, is normally parasitic in dogs and cats; man, however, is sometimes infected by this species in the southern United States, South America, and Asia.
Hookwormfilariform larva
Rhabditiform larvae that hatch from eggs are 250-300 µm long and approximately 15-20 µm wide.
Hookworm filariform larva
Hookworm eggs in unstained wet mounts, taken at 400× magnification
60-75 µm by 35-40 µm.
Ancylostoma duodenale
Copulatory bursa
Plasmodium
Anopheles mosquito
Schizont: Hepatic Stage
Recognizing Erythrocytic Stages:Schematic Morphology
TROPHOZOITERING
SCHIZONT GAMETOCYTE
Plasmodium falciparum
Rings: double chromatin dots; appliqué forms;multiple infections in same red cell
Gametocytes: mature (M)andimmature (I) forms (I is rarelyseen in peripheral blood)
Trophozoites: compact(rarely seen in
peripheral blood)
Schizonts: 8-24 merozoites(rarely seen in peripheral blood)
M I
Plasmodium vivax
Trophozoites: ameboid; deforms the erythrocyte
Gametocytes: round-oval Schizonts: 12-24 merozoites
Rings
Infected erythrocytes: enlarged up to 2X; deformed; (Schüffner’s dots)
Plasmodium ovaleInfected erythrocytes: moderately enlarged (11/4 X); fimbriated; oval; (Schüffner’s dots) “malariae - like parasite in vivax - like erythrocyte”
Rings
Trophozoites: compact
Schizonts: 6-14 merozoites; dark pigment; (“rosettes”)
Gametocytes: round-oval
Infected erythrocytes: size normal to decreased (3/4X)
Plasmodium malariae
Trophozoite:compact
Trophozoite:typical band form
Schizont:6-12 merozoites;coarse, dark pigment
Gametocyte:round; coarse,dark pigment
Species Differentiation on Thin FilmsFeature P. falciparum P. vivax P. ovale P. malariae
Enlarged infected RBC + +
Infected RBC shape round round, distorted
oval, fimbriated
round
Stippling infected RBC Mauer clefts Schuffner spots
Schuffner spots
none
Trophozoite shape small ring, appliqu
large ring, amoeboid
large ring, compact
small ring, compact
Chromatin dot often double single large single
Mature schizont rare, 12-30 merozoites
12-24 merozoites
4-12 merozoites
6-12 merzoites
Gametocyte crescent shape large, round
large, round
compact, round
Species Differentiation on Thin Films
P. falciparum P. vivax P. ovale P. malariae
Rings
Trophozoites
Schizonts
Gametocytes
Morphology
Malarial parasite trophozoites are generally ring shaped, 1-2 microns in size, although other forms (ameboid and band) may also exist.
The sexual forms of the parasite (gametocytes) are much larger and 7-14 microns in size.
P. falciparum is the largest and is banana shaped, while others are smaller and round.
Morphology
Ring form:
(Plasmodium vivax )
a ring of bluish cytoplasm with
a dot-like nucleus
Trophzoite of Plasmodium vivax
irregular cytoplasm and enlarged nucleus with malarial pigment
( hemozoin)
Schizont of P.vivax
multiple masses of nuclear chromatin
Gametocytes
Male gametocyte Female gametocyte
Note: compact cytoplasm and absence of nuclear division.
Ring form of P. falciparum
Ring with double nuclei Multiple infections
African sleep sickness Trypanosoma brucei gambiense
Tsetse Fly
Trypanosoma Diagnosis
African Trypanosomiasis in Travelers Returning to the United Kingdom
1- Detection of trypanosoma chancre after bite
The Tsetse bite is usually painful and may develop into a red sore called a chancre
2- Blood smear within 21 days from the bit , it will show the parasite
A blood smear from a patient with African trypanosomiasis. a centrally located nucleus, an undulating membrane, and an anterior flagellum. The two Trypanosoma brucei species that cause human trypanosomiasis, T. b. gambiense and T. b. rhodesiense, are undistinguishable morphologically. The trypanosomes length range is 14-33 µm
Trypanosoma brucei gambiense
trypomastigote
Taenia life cycle
Wet
mo
un
t.
Bro
wn
, str
iate
d e
mb
ryo
ph
ore
. C
an n
ot
dif
fere
nti
ate
T. s
agin
ata
fro
m T
. so
lium
The scolex of T. solium has hooks on its anterior end, while the scolex of T. saginata only has the four suckers.
Cercariae are about 1 mm in length
S.haematobium S. Mansoni egg
terminal spine
A lateral spine
Hymenolepis nana
القزمة الشريطية الدودة
The scolex has four suckers and an armed rostellum.
Hymenolepis nana: midll part of gravid progllottids (One of the segments of a tapeworm, containing both male and female reproductive organs )
1 cm long
Hymenolepsis nana. An egg of H. nana, with its characteristic double membrane.
50 µm, ovoid
Trichuris trichiura (whipworm)
eggs become infective in 15 to 30 days
The adult worms (approximately 4 cm in length)
1000 to 7000 eggs per day
Trichuris trichiura (whipworm )
The female measures 35 - 50mm long and the male 30 - 45 mm long. ova with bipolar plugs. They
measure 50 - 54m by 20 - 23m.
Trichinella spiralis
Larva in the skeletal muscle
Practical Diagnostic Parasitology
Lets Do Practise
