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 µM trophozoite15 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 microns Fertilized, corticated eggs Ascaris

Ascaris unfertilized or otherwise non-viable eggs Egg size(infertile): 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 µm by µm

Egg size: 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.

Hookworm filariform larva Rhabditiform larvae that hatch from eggs are µm long and approximately µm wide.

Hookworm filariform larva

Hookworm eggs in unstained wet mounts, taken at 400× magnification µm by µm.

Ancylostoma duodenale Copulatory bursa

Plasmodium Anopheles mosquito

Schizont: Hepatic Stage

Recognizing Erythrocytic Stages: Schematic Morphology TROPHOZOITE RING SCHIZONT GAMETOCYTE

Plasmodium falciparum Rings: double chromatin dots; appliqué forms; multiple infections in same red cell Gametocytes: mature (M)and immature (I) forms (I is rarely seen in peripheral blood) Trophozoites: compact (rarely seen in peripheral blood) Schizonts: 8-24 merozoites (rarely seen in peripheral blood) MI

Plasmodium vivax Trophozoites: ameboid; deforms the erythrocyte Gametocytes: round-oval Schizonts: merozoites Rings Infected erythrocytes: enlarged up to 2X; deformed; (Schüffner’s dots)

Plasmodium ovale Infected erythrocytes: moderately enlarged (1 1/4 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 Films

Morphology Malarial parasite trophozoites are generally ring shaped, 1-2 microns in size, although other forms (ameboid and band) may also exist. 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. 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. 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 gametocyteFemale gametocyte Note: compact cytoplasm and absence of nuclear division.

Ring form of P. falciparum Ring with double nucleiMultiple 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 µm

Trypanosoma brucei gambiense trypomastigote trypomastigote

Taenia life cycle

An egg of Taenia pisiformis

Wet mount. Brown, striated embryophore. Can not differentiate T. saginata from T. solium

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.haematobiumS. Mansoni egg terminal spine A lateral spine

Hymenolepis nana الدودة الشريطية القزمة

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 mm long and the male mm long. ova with bipolar plugs. They measure m by m.

Trichinella spiralis Larva in the skeletal muscle