Block 1 part 2 Flashcards
Parasitic flagellates can be:
A) Hemoflagellates that live in the blood, lymph, and tissue spaces (Trypanosoma and Leishmania), and are typically transmitted from host to host by bloodsucking insect
B) Mucosoflagellates that live in the alimentary or genital tract (in association with the mucous membrane)
Trypanosoma:
elongated, spindle-shaped cell with a single nucleus in the middle and a single flagellum that arises from kinetoplast (large mitochondrion with copious DNA
Four morphological forms
The amastigote (lack flagellum)
Trypomastigote (kinetoplast lies posterior to the nucleus)
Epimastigote (kinetoplast immediately anterior to the nucleus)
Promastigoe (kinetoplast is near the anterior end of the cell)
Trypanosoma brucei
Life Cycle
Conveyed through the bite of Glossina spp.(tsetese) to domestic livestock; multiplies by longitudinal binary fission in the blood, lymph, and cerebrospinal fluid of the mammalian host
• Trypomastigotes are ingested by the tsetese fly, multiply in the midgut, undergo metamorphosis, and migrate to the salivary glands, where they become infective metacyclic trypomastigote stage
Trypanosoma equiperdum
is unique in not requiring an intermediate host (transmission occurs through sexual contact
Trypanosoma cruz
It was also present in hunting dogs in central Virginia. Opossums, armadillos, rats, guinea pigs, cats, racoons, and monkeys serve as reservoir. It multiply by binary fission in mammalian cells.Infection can occur through placenta or blood transfusion. Individuals handling infected animal blood!!
Xenodiagnosis
Uninfected bugs are allowed to feed on suspected individuals and their hindguts are examined later. Inefficient !!
Trypanosoma brucei and T. congolense Disease
: Fatal nagana disease in domestic ruminants
The disease is obstructing grazing in many African areas
Trypanosoma gabiense and T. rhodesiense Disease
cause African sleeping sickness in human
Trypanosoma vivax Disease
Acute (hemorrhages from the mucosal and serosal surfaces, Chronic (anemia) or no disease in cattle
Trypanosoma evansi Disease
causes Surra in domestic animals
T. equinum Disease
causes a disease similar to surra in South American horses (called mal de Caderas)
Trypanosoma equiperdum (horses): Disease
Equine venereal disease called dourine. Acute form characterized by swelling of the genitalia and mucoid discharge, containing the parasites. As acute signs subside, circular flattened, “silver dollar” plaques appear in the skin
T. cruzi
causes Chagas’ disease (American trypanosomiasis
Trypanosoma Treatment and control
nifurtimox (4-Thiomorpholinamine
Benznidazole
Hemoflagellates
Leishmania spp.
Leishmania donovani
visceral leishmaniasis (kala-azar) in humans and dogs Foxhounds
Leishmania tropica
: cutaneous and mucocutaneous leishmaniasis in human, dogs, rodents, and wild mammals
Leishmania Control:
Pentostam: Pentostam
Trichomonads (group name) Mucosoflagellates
Pear-shaped
Tritrichomonas foetus
is found in the vagina, uterus, macerated fetus, prepuce, penis, epididymis, and vas deferens
Axostyle
Axostyle is a sheet of microtubules found in certain protozoa. It arises from the bases of the flagella, sometimes projecting beyond the end of the cell. Often flexible or contractile, and so may be involved in movement.
Trichomonds Life Cycle
Trophozoite in preputial epithelium of bull. Trophozoite enters reproductive tract of cow during coitus. Trophozoite multiply in both sexes by binary fission
Disease caused by Tritrichomonas foetus
Infertility, abortion and occasional fatal mummification (common in USA). Bulls are normally asymptomatic
T. vaginalis
causes vaginitis in women
T. gallinae
causes necrotic ulceration in the esophagus, crop, and proventriculus of pigeons, turkeys, and chickens
Histomonas meleagridis
is taken by the nematode Heterakis gallinarum. Birds become infected when they eat the nematode egg. Inflammation and necrosis of the cecal wall and the liver cause high mortality in turkeys
Giardia lamblia (mammals), Giardia muris (mice), and Giardia ranae (frogs
Giardia trophozoite cell: two nuclei (each with large endosome), and four pairs of flagella
Giardia Life Cycle
Giardia parasitizes the small intestine. Trophozoites attach to the mucosal cells by their sucking disks. Trophozoites form infective cysts
Giardia Disease
Causes enteritis and diarrhea in dogs, cats, calves, and humans
Giardia Control and Treatment
Prevention of fecal contamination of feed and water and sanitation. Fenbendazol and Albendazole
Entamoeba histolytica
a parasite of large intestine (amebic dysentery in humans
Endemic in the tropics and occurs sporadically in the temperate regions.
Entamoeba invadens
causes sever disease and death in reptiles