vmp 920 infection & immunity ii veterinary parasitology protozoa
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VMP 920Infection & Immunity II
Veterinary Parasitology
Protozoa
Giardia sp.Cyst
Infectious form
Trophozoite Active form
Replication leads to Pathology
Replication(binary fission)
Giardia sp.
Life Cycle
Cysts areimmediately infectiouswhen passed in feces.
Pathology
• Giardia causes irritation / death of epithelial cells, elicits immune reaction
• Giardia & Host Immune factors contribute to pathology
• Mal-digestion, mal-absorption, hypersecretion, increased transit => enteritis & diarrhea
Clinical Signs & Diagnosis
• Trophs in diarrhea direct fecal
• Cysts in formed stool fecal float (zinc sulfate)
• ELISA tests for Giardia antigen in stool
Diagnostics
Direct fecal --- Positive: Trophozoite (Active form) ELISA Test --- Positive http://www.youtube.com/watch?v=aF06jlbcF8E
Diagnostics
Fecal Float --- Positive: Cyst (Infectious form) ELISA Test --- Positive
Treatment & Control
• Fenbendazole, Albendazole, Metronidazole, Quinacrine
• Sanitation - remove cysts from environment
Challenge to Control
Sanitation (especially since cysts are infectious as soon as they are passed in feces)
Eimeria sp.
Sporulation
Non-infectiousUn-sporulated
oocyst
InfectiousSporulated
oocyst
hours to days
Eimeria sp.
Sporozoite, Merozoite (Meront) Active Pathogenic form
Life Cycle
Life cycle image
Pathology
• Coccidea pathology slide
Pathology
• Destruction of host cells• Hemorrhagic diarrhea• Concomitant infections (bacterial,
viral) may play a role.
Pathology & Immunity
• Interplay of acquired immunity & initial dose of infection affects the severity of pathology.
• Which is more likely to show disease? A. Confinement poultry B. Free-range poultry
Clinical Signs & Diagnosis
• Asymptomatic to fatal hemorrhagic diarrhea
• Initial Pathology may occur prior to oocyst shedding
• Oocysts fecal float
• Prior stress may cause onset of coccidial diarrhea
Treatment & Control
• Treat symptoms (supportive therapy)
• Sanitation = clean oocysts from environment
• Coccidiostats in production animals
• Acquired or incomplete immunity for some coccidial species (vaccine research)
Challenge to Control
Sanitation
(Assume infection => coccidiostats)
Babesia sp.
Troph in RBC Intracellular form
Life Cycle
Life cycle image
Other routes of Transmission: Transplacental & Transfusion
Transmission in Tick population:Transovarian & Transstadial
Pathology
• Destruction of host RBC’s anemia
• Acute DZ death
• Or Chronic illness
Hemolytic anemia, thrombocytopenia, hyperglobulinemia, icterus, fever, splenomegaly, and lymphadenopathy
Clinical Signs & Diagnosis
• Hemolytic anemia, fever, jaundice, listlessness, anorexia, splenomegaly, lymphadenopathy, etc.
• Intra-erythrocytic parasites on blood smear
• Serology; PCR
Treatment & Control
• Imidocarb, Berenil
• Pest Control --- Ticks
Challenges to Control
Pest control (tick vectors) – Transstadial &
Transovarian
“Sanitation” - Transfusion
Assume infection - Transplacental
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