Parasitic Infections of the MSK II Flashcards
What is sarcocystitis?
- Protozoan parasite
- Highly prevalent parasite of livestock
What is the definitive host of sarcocystitis?
dogs, cats, humans
What is the intermediate host of sarcocystitis?
herbivores e.g ruminants
What are the pathogenic species of sarcocystitis?
- bovicanis
- ovicanis
- suicanis
What does a heavy sarcocystosis infection look like?
- anorexia
- anaemia
- weight loss
- recumbancy
- lameness (pigs)
What does sarcocystosis look like in lambs?
myositis, encephalomyelitis
What does sarcocystosis look like in cattle?
- submandibular oedema
- hair loss at the end of the tail
What is the pathogenesis of sarcocystosis?
- Clinical signs are due to schizogony in vascular endothelium-> endothelial cell destruction
- haemorrhages occur in a variety of organs
- microscopic lesions in organs- necrosis, oedema, and infiltration sof mononuclear cells
What does sarcocystosis look like in the chronic phase?
- Cysts in muscles- generally microscopic
- Lesions cause myositis and degeneration of sarcocysts
How could you diagnose sarcocystosis?
- Indirect haemagglutination
- PCR on muscle tissue
- Examine of faeces
When is sarcocystosis infection most likely?
When there is a close association between dogs or cats + farm animals
How do humans become infected with intestinal sarcocystosis?
infection through consumption of undercooked meat
What is the pre-patent period of intestinal sarcocystosis of humans?
10-17 days
What are the clinical signs of intestinal sarcocystosis in humans?
- nausea
- vomiting
- acute/ chronic enteritis
What is the lifecycle of sarcocystitis?
- Intermediate host is infected via sporocyst ingestion
- Sporozoites invade epithelium and enter the endothelial cells in bood vessels
- 1-3 rounds of schizogony in endothelial and mononuclear cells
- merozoites are released which penetrate muscle cells
- encyst and divide -> bradyzoites
