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
Ciliophora
ciliates)
Balantidium coli:
Cell surface is covered with cilia
Very large as a single cell
TX: Dehydroemetine dihyrochloride
Coccidians:
develop in epithelial cells of alimentary canal (enteritis); transmitted by fecal contamination
Hemosporidians:
develop in erythrocytes and cause hemolytic anemia; transmitted by bloodsucking arthropods
Coccidia
Infective Form
Sporozoites (infective forms) found in sporulated oocysts
Eimeria
Life Cycle
Gastrointestinal parasites of many vertebrates
: Asexual (oocysts with 8 sporozoites) and sexual stages
Trophozoite
Oocyst divides into four sporoblasts (sporulation) each giving a sporocyst (containing two haploid sporozoites), giving the infective sporulated oocyst
Eimeri tenella, E branetti, E. maxima, E mitis, E. acrvulina
affect birds
E. bovis and E zuernii
Causes bloody diarrhea. causes severe illness and death may occur even before oocysts appear
Eimeri Control
Proper sanitation; sulphonamides
Cystoisospora felis
Sporozoites may encyst (singly) in the tissues of the mouse. A cat become infected either by ingesting sporulated oocysts or infected mouse (serve as facultative paratenic host)
Diagnosis of Cystoisospora
. Diagnosis depends on identification of oocysts in feces
Cystoisospora (isopora)
Hammondia, Toxoplasma, Besnoitia and Sarcocystis
Cystoisospora felis and Cystoisospora rivolta in cats:
In dogs and cats the disease is characterized by copious and watery diarrhea for several weeks
Cystoisospora suis
causes noenatal coccidiosis in pigs (1-2 weeks old); survivals are completely immune. Birds remain the most affected animals by coccidians
Treatment and control of Cystoisospora
Sulfonamide for dogs and cats; sulfadimethoxine for dogs. Amprolium, monensin or sulfa drugs for cattle
Cryptosporidium
• Tiny (oocysts are 4-8um in diameter). In microvillous borders of enteric epithelial and also in gallbladder, respiratory, and renal epithelium
Cryptosporidum
Life History
Infective oocysts are passed in feces. Contain 4 sporozoites. They can remain infective for months. When ingested by a host, oocysts release the sporozoites that invade microvillous borders of the gastric glands or lower half of the small intestine. T
Cryptosporidum Disease
: Mammals, avian, reptilian, and piscine host. Diarrhea. Only small proportion of the infected mammals develop disease.corytosporidiosis in cats is associated with feline leukemia virus causing immunodeficiency
Toxoplasma gondii
• Coccidian of the domestic cat, which are the only known definitive host. Any warm-blooded animal may serve as a paratenic host
Toxoplasma gondii
Life Cycle
Oocyst contains a single sporont (not infective). Sporulation takes 1-5 days giving two sporocysts (infective) each containing 4 sporozoites
Bradyzoites (?) are then formed in the brain, striated muscles and liver (they remain viable for the whole life the host). Bradyzoites are infective
Transplacental transmission of tachyzoites is possible
Toxoplasma Disease
Un-cooked pork is an important source of infection
Treatment of toxoplasmosi
Cat are treated with Clindamycin hydrochlorid
Neospora caninum a
parasite of dogs and cattle. Causes bovine abortion among dairy cows. Congenital infection is common. Infection affect milk production
Hammondia hammondi
a rare parasite of cats. Pigs, rats, mice, goats, hamsters, and dogs serve as intermediate hosts.
Hammondia heydorni
parasite of dogs, foxes, and coyotes (cattle, sheep, goats, camels, water buffalo, guinea pigs, and dogs serve as intermediate hosts). Tachyzoites give bradyzoites.
Hammondia Life Cycle
• Two-host life history, as for H. hammondi, but only sexual reproduction occurs in the definitive host. Sporogony is completed in the definitive host. Asexual reproduction occurs only in the intermediate host. Compare with Hammondia hammondi.
Hammondia Control
Cooked beef for dogs and cats. Avoid contaminating cattle feedstuffs with canine feces
Sarcocystis neurona
It causes severe neurological disease in horses
It is known as equine protozoal myeloencephalitis (EPM)
• Sarcocystis neurona
Diagnosis
: Finding EPM organisms in Central nervous system. Western blot analysis of serum or cerebrospinal fluid. PCR on cerebrospinal fluid
Hepatozoon americanum
in US causes disease in dogs (vector: Amblyoma maculatum tick). • Diagnosis: Gamonts in peripheral blood (H. canis). Muscle tissue examination (biopsy) for H. americanum
• Disease: Neutrophilic leukocytosis, joint pain associated with myositis and periosteal bone proliferation
Babesia spp
• Parasites of erythrocytes; causes bovine piroplasmosis (“Texas fever”). Apple-seedlike, found in pairs in erythrocytes
Babesia Life Cycle
Boophilus annulatus and B. microplus are the vectors
Vertical transmission to ovary
Sporozoites enter the host’s erythrocytes.
Two ray bodies fuse to form a zygote
Diseased Caused by Babesia (Piroplasmosis)
acute cases mortality is as high as 50-90%. First sign is a high fever. Cattle become dull, lethargic and lose their appetite. Severe anemia results from destruction of erythrocytes. Jaundice.
Control and Treatment of piroplasmosis
Elimination of the vector. Regular cattle dipping in a tickicide. Artificial pre-immunizing of calves with a mild strain before shipping to other areas
Babesia canis and B. gibsoni infect dogs
The first has pear-shaped trophozoites. The second are round to oval in shape
Babesia
Diagnosis
Demonstrating trophozoites in erythrocytes
Theileria
East cost fever of African cattle. Occurs in erythrocytes, lymphocytes and endothelial cells. Transmitted by Rhipicephalus and Hyalomma spp. Heavy mortality
Horse fly as vector
Theilaria
Treatment
Parvaquone, Buparvaquone, Halofuginone
Cytauxzoon felis
cytauxzoonosis) of cats in south central US). Pyrexia, anemia and dehydration; causing death within few days
Cytauxzoon felis
Diagnosis
Giemsa-stained blood smears. (light blue cytoplasm and dark red nucleus). Dermacentor variabilis has been shown experimentally to serve as transstadial vector
Plasmodium Spp
Cause disease in humans, primates, rodents, birds, and reptiles. The vector for mammals is anopheline mosquitoes. The vector for avian malaria is culicine mosquitoes.
Plasmodium Spp
Life Cycle
Sporozoited Infective Stage
Vector Mosquito
Gramtocytes are infective to mosquitoes
Plasmodium Spp
Disease
Cerebral involvement, renal failure, or pulmonary hemorrhage (fatal). P. knowlsi and P. cynomolgi of nonhuman primates (transmissible to human)
Plasmodium Treatment
Treatment of malaria: Chloroquine. Quinine
Haemoproteus spp
In birds, turtles, and lizards. Schizogony occurs in vascular endothelial cells of various organs and only gametocytes appear in erythrocytes
Haemoproteus Trasmi
tted by
Culicoides, Hippoboscidae, or Chrysops
• Leucocytozoon spp.:
Parasites of domestic and wild birds
◦ L. simondi: Ducks and geese (fatal)
◦ L. caulleryi: chickens
◦ L. smithi: turkeys
Leucocytozoon Spp
Life Cycle
Similar to that of plasmodium. Gametocytes here do not have pigment granules and distorting the cell. Simulium spp. serves as intermediate host
Hepatocystis spp
.: Parasites of the lower monkeys, fruit bats, and squirrels in the Old World. Schizogony occurs in hepatocytes (2 months), resulting in large schizonts called merocysts
Hepatocystis Transmitted by
Culicoides
