Pig Neonate Diarrhoea

Question 1

Piglets born from first parity mothers seem to be affected more than those from older sows
In the litters affected, most piglets show some clinical signs
Some of the piglets affected are huddled together in a corner, the farmer had found a couple of dead piglets and had kept one for you in a fridge to look at.

What are the likely differentials? (4)

Answer 1

• Transmissable gastroenteritis - corona vius
• Rotavirus
• Clostridium perfringens
• E.Coli

Question 2

What are the likely differentials (6)

Answer 2

• Adenovirus
• Salmonella
• Coccidia
• Rotavirus
• Cryptosporidum
• Transmissable gastronteritis

Question 3

You suspect colibacillosis in the younger piglets as your top differential diagnosis.

What samples do you need to submit for a definitive diagnosis to distinguish between commensal and virulent E.coli? (3)

Answer 3

• Necropsy samples of the gut with gut content
• Rectal swab
• Live piglet for euthanasia

correct, this will allow histology and to visualize bacteria attached to the gut and bacterial culture. Various sections of ilium and jejunum will be required, some submitted fresh/chilled and some in 10% formalin. Not ideal since it will not give any information on the pathology caused by the diseae but it will allow the culture of bacteria. However, sicne it is taken rectally rather than from the ilium, a lot of the bacteria isolated will be part of the normal rectal flora. In neonates you will get very little material, not enough to, for example, test for rotavirus. This is the best option since it is paramount that the samples are taken and processed rapidly after death of the piglet. A range of ilial and jejunal sections and gut content can be taken to allow histology, bacterial culture and PCR.

Question 4

What diagnostic tests need to be performed to identify virulent enterotoxigenic E coli likely to cause disease in neonatal piglets? (2)

Answer 4

• Agglutination or PCR for fimbrae, ie K88
  
  • This is an essential test, since fimbriae are essential for cell adherence and virulence
• PCR for E.Coli toxin genes/virotyping
  
  • this is another appropriate diagnostic approach to distinguish between commensal non-toxin producing E. coli and pathogenic E. coli

Question 5

Another common cause of neonatal diarrhoea is Rotavirus. Which quick tests would allow you to distinguish between diarrhoea likely caused by rotavirus from that likely caused by E. coli? (2)

Answer 5

• PCR to identify either E.Coli or rotavirus DNA
  
  • This is a correct diagnostic procedure but does require samples to be sent to a veterinary laboratory, there is a quick test that can be done on farm
• Litmus paper to determine pH of diarrhoea
  
  • E. coli diarrhoea is alkaline (blue colour change) whereas malabsortive diarrhoe caused by viral infections are acid (red colour change) - while quick this is not a definitive diagnostic test!

Question 6

Culture of colon samples on blood and McConkey agars show heavy pure growth of lactose-fermenting, indole-positive, oxidase-negative and beta haemolytic colonies of Gm-coliforms. Agglutination reactions indicate K88+. Flotation and smears show no oocysts evident.

What is your interpretation of those findings?

Answer 6

• This is indicative of of enterotoxic E coli bacillosis because the bacteria are positive for the K88 fimbrae

Question 7

Culture of colon samples show moderate, mixed growth of bacteria. Flotation and smears of faecal sampesl shows numerous coccidial oocysts

Which clinical signs would you expect with this? (2)

Answer 7

• Creamy grey diarrhoea
• Reduced growth rate

Question 8

Develop a treatment plan for E.Coli in pigs

Answer 8

Individual cases may be treated with an appropriate oral antibiotic - determined by sensitivity testing, given at the earliest sign of diarrhoea. In an outbreak, strategic medication of all pigs at birth may be necessary. Where one pig in a litter is noticed with diarrhoea it is usually appropriate and fully justifiable to treat the whole litter metaphylactically at that time.

Equally important as part of the treatment programme is the provision of electrolytes to reduce the severe dehydration that actually kills many piglets. These must be kept clean and fresh, and in severely affected pigs be actively administered orally e.g. by syringe.

Question 9

Devlelop a treatment plan for coccidia in pigs

Answer 9

• For this to be effective it must be given just prior to the invasion of the intestinal wall. Once clinical signs have appeared the damage has been done.
• Medicate the sow feed with either amprolium premix 1kg/tonne, monensin sodium 100g/tonne or sulphadimidine 100g/tonne. Feed from the time the sow enters the farrowing house and throughout lactation.
• Inject each litter with a long-acting sulphonamide at six days of age.
• Medicate small amounts of milk powder with a coccidiostat such as amprolium or salinomycin and give small amounts daily to the piglets from three days of age onwards top dressed on the creep feed.
• Piglets: Individual animal treatment. Each pig to be treated on day 3-5 of life with a single oral dose of 20 mg toltrazuril/kg body weight corresponding to 0.4 ml oral suspension per kg body weight. Due to the small volumes required to treat individual piglets, use of dosing equipment with a dose accuracy of 0.1 ml is recommended. Treatment during an outbreak will be of limited value for the individual piglet because of damage to the small intestine having already occurred.

Question 10

How can we manage E. Coli in pigs?

Answer 10

• Reducing spread of infection
• Reducing reservoir of infection
• Increasing immunity in sows and piglets
• The disease will spread by any physical movement of scour between pens and buildings. Use of disinfectant foot dips between pens and rooms if vital - keeping the foot dip fresh, clean and at the correct dilution rate.
• Control of flies, mice etc is also vital.
• Using separate dedicated equipment in pens with scour
• Active cross-fostering of piglets is discouraged in the face of an outbreak, and on no account should pigs be moved from room to room, especially where there are age differences.
• The farrowing pen in which a previous litter has been affected is a reservoir of infection if not thoroughly cleaned. Cleaning should involve the use of detergents to remove the protective grease film (derived from high fat lactation and creep diets), power washing and disinfecting - using a DEFRA approved product at the appropriate dilution rate. The longer the pens can be rested between batches the better. Fumigation of rooms may be an additional technique to employ. Removal of slurry from channels under slats reduces the risk of flies bringing infection back to the pen surface but if performed, must be thorough.
• Cleanliness of the sow is also important. The sow should, if grossly contaminated, be washed and dried before entry to a clean pen and she should not spend an excessively long time in the crate before farrowing - 3 to 5 days is preferable. Legally it cannot be more than 7 days.
• In the outdoor environment, burning or removal of old beds, moving of farrowing arcs and avoidance of lying boards will all help control disease, subject to an exemption licence for the burning of bedding from the Environment Agency.
• Immunity in the gilt and sow results from exposure to E coli regularly and continuously and can be raised by:
  
  • Controlled exposure of gilts and sows- an old-fashioned technique now of questionable legality. (Previously referred to as “feedback”) Scour from the affected litters can be mixed back to gilts and sows in late pregnancy (no earlier than 75 days gestation) for 3 to 4 weeks prior to entry to farrowing house. Typically, small amounts of scour collected on tissues should be offered to late pregnant animals twice weekly. Feedback should cease prior to entry to a clean farrowing pen. This should only be done under specific veterinary direction and never as a routine practice.
  • Exposing gilts prior to service to animals present on the farm such as cull sows may also assist exposure and the consequent development or boosting of immunity
  • Loose housing systems will tend to encourage exposure to gut based bacteria and may reduce the overall risk of E coli disease in sow litters.
  • Vaccination - there are several proprietary vaccines on the market to administer to gilts and sows prior to farrowing. Each has a slightly different protocol and it is vital that the correct protocol is followed if the vaccine is to be effective. They are not consistently interchangeable.
  • It should be appreciated that the injectable vaccines raise systemic immunity in the sow, which is spread to colostrum and transferred to piglets. As such, they will only tend to protect the piglet in the first 3 to 4 days of life whilst that colstrum bathes the gut lumen, and are largely ineffective for controlling disease associated with E.coli infection in older piglets. (Specific piglet E coli vaccine is available for the control of E coli induced Bowel Oedema post weaning).
  • Combination vaccines covering Clostridia may be appropriate in some cases, especially in outdoor units.
  • All vaccines are only effective against the organism to which they are targeted - they will not cover every cause of disease - and rely upon ensuring adequate colostrum intake in every piglet early enough in life.
  • Long term treatment of piglets with broad spectrum antibiotics at birth to prevent E coli infection in young piglets is not an appropriate approach to take; not only does it increase the risk of selecting for antibiotic resistance but also can damage the development of the normal gut flora (microbiome) leading to digestive problems at and beyond weaning.

Question 11

How can you manage coccidia in pigs

Answer 11

Hygiene plays a major part in the control of Coccidosis. The oocysts that are shed in the faeces, which develop into infective stages in the environment - provided the temperature exceeds 16°C - are very resistant to conventional disinfectants. Effective treatments are fire (flame gun) and limewashing - in the latter case, the lime must be allowed to cure for 3-4 days before stock are placed in the treated pen. Conventional and widely used disinfectants (iodophores, organic acids or even phenols) are not effective at killing coccidial oocysts which can survive and remain infective for up to 10months A specific anti-coccidial disinfectant - Oocide-is no longer available; this was a 2 component product that, when mixed, gave off ammonia gas. There are claims that some dry disinfectants have anticoccidial effects and may be useful adjuncts to treatment of the environment. Thorough washing of pens with a detergent is vital and problems typically - though not exclusively - occur in continually occupied rooms and on certain type of floors where thorough cleaning is difficult (solid, cracked concrete, moulded plastic slats) and where slurry is left under slats between farrowing groups.. Whilst conventional disinfectants have poor efficacy against the oocysts, if used correctly they are highly effective against other pathogens and should form part of the general cleaning programme.

• Once the oocysts have become established in an environment the sow plays only a minor role. The oocysts contaminate the environment by other means such as flies, dried faeces, dust and faeces contaminated surfaces. Hygiene and insect control are important.
• Remove sow and piglet faeces daily.
• Improve the hygiene in farrowing houses, in particular farrowing pen floors and prevent the movement of faeces from one pen to another.
• Ensure as far as possible that slurry channels are completely emptied between farrowings.
• Thoroughly wash and disinfect the farrowing houses with OO-CIDE (Antec) or other substances that are active against oocysts.
• If farrowing crate floor surfaces are made of concrete and pitted, brush these over with lime wash and allow it to dry before the next sow comes into farrow. See chapter 15.
• Keep pens as dry as possible and in particular those areas of the floor where the piglets defecate. An effective method is to cover the wet areas with shavings and remove them daily.
• If creep is fed on the floor stop creep feeding until piglets are at least 21 days old.
• Control flies. See Flies chapter 11.
• In outdoor herds control can be difficult. Always move farrowing arcs to new ground between farrowings and burn bedding.
• If floor boards are used in farrowing arcs disinfect these with OO-CIDE (Antec).
• Wallows can be an ideal focus of infection particularly during lactation. Increase the amount of shade and provide sprays. Provide alternating wallows.
• Site wallows well away from the source of food.
• For the prevention of clinical signs of coccidiosis in neonatal piglets on farms with a confirmed history of coccidiosis caused by Isospora suis.