Diarrhoea In Farm Animals Flashcards
What are the three key influencing factors in cases of diarrhoea in large animals?
Pathogens,
Management
Host factors (immune system, stress)
What husbandry factor is key in insuring the health of calves?
COLOSTRUM
What perspectives do you have to consider when treating a farm animal?
The animal
The farm
Public health - farm staff and consumers
What broad categories of causes are likely responsible for diarrhoea?
Host factors
Environment and management
What host factors can result affect diarrhoea?
Age
Co-infections
Vaccinations
Dystocia
What environment and management factors affect diarrhoea?
Management grouping
Cleanliness
Nutrition
COLOSTRUM
What pathogens would you consider if a calf presented with acute diarrhoea?
E.Coli (<5 days) Cryptosporidia (5-14 days) Rotavirus (7-14 days) Coronavirus (7-22 days) Coccidia (> 3 weeks) Salmonella (All ages)
Which pathogen could be responsible for diarrhoea in a calf less than 5 days old?
E.Coli
Which pathogen could be responsible for diarrhoea in a calf between 5 days and 2 weeks old?
Cryptosporidia
Rotavirus
Coronavirus
When can calves be infected with salmonella?
All ages
Why should the presence of E.Coli be interpreted with care in a faecal sample?
All faeces will grow E. Coli when cultured
Describe the morbidity and mortality of Rotavirus.
What sections of the GIT does it affect?
High morbidity, low mortality
Duodenum and Jejunum
Describe the morbidity and mortality of coronavirus in calves.
What sections of the GIT does it affect?
Slightly higher mortality than Rotavirus
Ileum, Caecum, Colon
What part of the GI tract does crypto involve?
What happens?
Lower part of SI and colon
Villous atrophy causes malabsorption
What is the most important public health issue affecting calves?
Salmonella
Why is it important to identify the species of salmonella present?
Important in identifying the source
Why is it important to keep milk buckets high?
Make sure that oesophageal groove closes and milk goes into the abomasum.
What are some likely causes of acute diarrhoea in adult cows?
Salmonellosis Winter dysentery (Coronavirus) Acidosis/SARA Malignant Catarrhal Fever Poisons (Ragwort, Arsenic) Mucosal Disease (clinical manifestation of BVD)
What is winter dysentery?
Coronavirus
Diarrhoea stops in 3-4 days
Will recover but have a decreased milk yield and reduced fertility
What type of virus is BVDV/BVSD?
Pestivirus
What are the most common causes of acute diarrhoea in cattle?
Salmonellosis
Winter Dysentery
Acidosis/SARA
What are causes of chronic diarrhoea in adult cows?
Which are most likely
Johnes
Ostertagia
Fluke
Mucosal Disease
Johnes, Ostertagia, Fluke
What is the most likely clinical presentation of a patient with BVDV?
FERTILITY ISSUES AND ABORTIONS
Quite rarely causes diarrhoea
What is likely to cause diarrhoea in lambs?
Watery mouth
Poor maternal milk production
Rotavirus Coronavirus Crypto E.Coli Salmonellosis Lamb dysentery (C. perfringens)
What are the causes of diarrhoea in 3-12 week old lambs?
Which are most likely?
Coccidiosis
Nematodirus
Teladorsagia
Tick-borne fever
Coccidiosis
Nematodirus
How could you tell if there is faeces in the water?
Culture - E.Coli will be present
What type of E.Coli causes scour?
ETEC
ETEC colonises small intestine
2 days to 1 week old, watery diarrhoea, yellow bum staining
How can a neonatal calf/piglet/lamb get infected with ETEC?
How does ETEC cause pathology?
Colonisation of Lower small intestine following ingestion.
Stunting of villi
often in conjunction with rotavirus
What does ETEC require?
How are they encoded?
Adhesive fimbriae
Enterotoxin
On plasmids, sometimes on same plasmid
What is the importance of adhesive fimbriae to ETEC?
Required for specific attachment
Why are ETEC strains often not zoonotic?
Colonisation factors are specific to different species
What are the two types of enterotoxins produced by ETEC?
Labile Toxin (LT)
Stable Toxin (ST)
How does LT affect the intestines?
Attaches to brush border of small intestinal cells.
Disturbs normal signal transduction - increases cAMP, Chlorine channels activated, Cl- secretion increased.
Na+ and H20 lost from tissue into lumen
= SECRETORY DIARRHOEA
How can LT be fatal?
Dehydration and electrolyte loss with consequent metabolic acidosis sometimes fatal.
How can you diagnose ETEC?
NOT faecal culture - E.Coli always present
Need to show BOTH:
- Toxin - e.g. LT or gene for LT
- Fimbriae- e.g. K88 or gene for K88
What strain of E.Coli is a public health issue?
STEC - Shiga-toxin producing E.Coli
Causes effacement of villi and diarrhoea and haemorrhagic colitis in calves
Can be picked up by public e.g. farm shows, petting zoos and CAN KILL children and elderly
How should you examine the faeces of cows?
Take SAMPLES (not swabs)
Take the samples from healthy and affected animals to see if the pathogen profile is different.
What nutritional factors are essential for calves?
Clean, fresh water and adequate good quality colostrum.
Fresh concentrate
What pathogen causes Johnes disease?
Mycobacterium avium subspecies paratuberculosis (MAP)
How does Johnes usually present ?
Older animals (4/5 years)
Severe ‘Hose pipe’ bubbly diarrhoea and weight loss
AFFECTED ADULTS INFECTIOUS
How are animals with Johnes treated?
No treatment or cure, need to be culled on humane grounds.
Is Johnes a public health risk?
Not always removed by routine pasteurisation
MAP could be linked to Crohns / IBD in humans
How do animals get Johnes?
Acquired by young stock (from infectious adults) but becomes clinical several years later.
How can Johnes be controlled?
Preventing young animals from being infected by faeces of adults(shouldn’t house adult cows and calf’s together)
AVOID POOLED COLOSTRUM - MAP can be transferred in colostrum
Identify subclinical infected adults (difficult!!!)
How can MAP be diagnosed?
ELISA blood - low sensitivity high specificity - if you get a positive result, almost definitely infected.
Stain - ZN for acid fast bacteria
Faecal culture
PCR individual
Gut biopsy
Necropsy
How much colostrum should a calf get?
6 litres in the first 12 hours
