Protozoal Gut Infections Flashcards
What are the three common features of gut protozoa?
- Via faecal/Oral Transmission
- Have at least one life stage in the GIT
- they shed environmentally resistant stages into the faeces
What two species make up coccidia?
Eimeria and Isospora species
* they are obligate intracellular pathogens
* usually host specific
* most of their life stages are non-motile
How do Eimeria reproduce?
via schizogony (asexual reproduction via multiple fission)
What animals does coccidiosis effect?
Primarily young animals, e.g poultry, lambs and calves
What is the primary clinical sign of coccidiosis?
Bloody Diarrhoea
coccidiosis is the cause of major production losses
How may you diagnose coccidiosis in poultry?
- Clinical signs
- Lesion location
- Microscopy (content, intestinal wall scrapes, oocytes, histopathology)
What is the epidemiology of coccidiosis in day old chicks?
They start with no immunity
there is then rapid parasite multipilication
many oocysts shed after 7 days
What are coccidiosis infections like?
Infections are often self-limiting and followed by immunity
the disease is most common in young birds of 3-8 weeks
What two species cause ovine coccidiosis?
E. crandallis & E. ovinoidalis
What parts of the GIT does ovine coccidiosis effect?
- Ileum, also caecum and colon
What does ovine coccidiosis look like histologically?
– villous atrophy, crypt hyperplasia, cellular infiltration, oedema &
haemorrhage
What is the multiplier effect with lamb coccidiosis?
lambs shed many more oocytes than they ingest
What causes lambs to be the most susceptible to ovine coccidiosis?
- they are 4-12 weeks old
- With no previous exposure
- Stressed due to cold, wet weather, and poor nutrition
- If there is co-infection with Nematodirus
What causes a high oocyte of ovine coccidiosis?
- There is faeces in the water or food supply
- there is dirty conditions around the food and water troughs
- overstocking
- the older lambs were previously on grazing or in building
What increases the chances of bovine coccidiosis?
- Intensive Rearing
- Cattle are young, 1-2 months to 1 year
- it is less common in older animals
What are the sub-clinical, clinical and severe symptoms of bovine coccidiosis?
Subclinical
* faecal staining of perineum, reduced feed efficiency, oocysts in normal faeces
Clinical
* Watery diarrhoea but with little to no blood, lasts a few days
Severe
* Bloody diarrhoea or thin faeces
* anorexia, depression, dehydration
What are the key factors for Cryptosporidium?
- It is apicomplexan
- A common GI infection of mammals
- Primarily waterborne
- found in fresh produce
- undergoes zoonotic transmission
What are the clinical signs of bovine cryptosporidious?
- Common cause of scouring in calves
- high morbidity, low mortality
- yellow-green diarrhoea with mucus
- mild dehydration
- The diarrhoea is due to the loss of the absorptive intestinal lining
What is the epidemiology of bovine cryptospridiosis?
- The older animals tend to be carriers and shed low numbers of oocytes
- environmental contamination and disease in the second half of the calving period
- transmission from lambs, cat and vermin
- oocysts can survive several months in cool, moist conditions
What parasite causes Giardia?
Giardia duodenalis
What animals are most at risk of giardia?
It is a parasite of young animals, the adults act as carriers
What is the epidemiology of Giardia
Parasite attaches to cells of the small intestine- non invasive
Dense layer of parasites interferes with absorption
Can damage epithelial cells and cause inflammation
What does the Giardia severity depend on?
- Parasite strain
- Immune status
- Gut flora
What is giardiasis like in cattle?
- Often asymptomatic but can cause diarrhoea in young animals
- Clinical signs- pasty diarrhoea, weight loss, lethargy
