The life cycle

Tiny-egg like infected structures called oocysts are passed out in the faeces into the environment where they develop (sporulate). This takes place within 12-24 hours at temperatures between 25º-35ºC (77ºF-95ºF). Oocysts can survive outside the pig for many months and are very difficult to kill. They are resistant to most disinfectants but OO-CIDE (Antec) is effective. The oocysts are eaten and undergo three complex developments in the wall of the small intestine to complete the cycle. It is during this period that damage occurs. Sows faeces are one source of infection and it is important that they are removed daily from the farrowing house. The life cycle in the piglet takes 5-10 days and disease therefore is not seen before five days of age.

Clinical signs

Coccidiosis causes diarrhoea in piglets due to damage caused to the wall of the small intestine. This is followed by secondary bacterial infections. Dehydration is common. The faeces vary in consistency and colour from yellow to grey green, or bloody according to the severity of the condition. Secondary infection by bacteria and viruses can also result in high mortality, although mortality due to coccidiosis on its own is relatively low. Occasionally disease is seen in young boars and gilts that are housed in permanently populated pens and floor fed.

Diagnosis

Coccidiosis should be suspected if there is a diarrhoea problem in sucking pigs from 7-21 days of age that does not respond particularly well to antibiotics. Diagnosis however is not easy in some outbreaks because identifying oocysts in the faeces of infected pigs can be difficult. In other outbreaks however clear signs are evident at post-mortem examinations. The oocysts do not pass out into the faeces until approximately 3-4 days after diarrhoea is seen, by which time the pig may have recovered. Faeces samples for laboratory examination should be taken from semi-recovered pigs rather than pigs with scour. Diagnosis is best made by submitting a live pig to the laboratory for histological examination of the intestinal wall. Isospora suis is the most pathogenic of the three types of coccidia.

Treatment

• 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.
• One or two doses of Toltrazuril at a level of 6.25mg/kg is effective in controlling disease. It is prepared by mixing 250ml of glycerol, 125ml water and 125ml of Baycox together. A 2ml dose may be given once at 4, 5 or 6 days of age, the exact time determined by the response, and repeated again at ten days of age. If there is no response it is unlikely that coccidiosis is the problem. Specifically discuss this method of treatment with your veterinarian who may prepare this for you.