VMP 920 Infection & 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 are immediately infectious when 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

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-infectious Un-sporulated oocyst Infectious Sporulated 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