Coccidiosis in Swine
Epidemiology: Coccidia are common in swine, but we know little about the prevalence and importance of the disease, coccidiosis. Enteritis is so common in young pigs and is caused by so many different agents that they have not all been sorted out and their importance assessed. Coccidia are among the least known of these agents.
Coccidiosis is primarily a disease of young pigs. Adults are carriers. Eimeria debliecki is probably the most pathogenic species, but E. scabra and Isospora suis may also cause disease.
Pigs become infected by ingesting sporulated oocysts along with their feed or water. The presence or severity of the disease depends upon the number of oocysts they receive. Crowding and lack of sanitation greatly increase the disease hazard.
Avery (1942) found that the oocysts of E. debliecki and E. scabra could survive and remain infective in the soil for 15 months. The soil surface temperature varied between -4.5° and 40° C during this period. Unsporulated oocysts withstood continuous freezing at -2° to -7° C or alternate freezing and thawing at 0.5° and -3° C for at least 26 days, altho subsequent sporulation was somewhat decreased.
Immunity: Repeated infections over a period of time confer immunity to coccidiosis. Biester and Schwarte (1932) produced complete immunity in pigs by feeding oocysts daily for 100 days or more. Light infections produced partial immunity. The coccidia of swine are not transmissible to other farm animals, and pigs cannot be infected with their coccidia.
Diagnosis: Coccidiosis in swine can be diagnosed by finding the endogenous stages in lesions in the intestine. The presence of oocysts in the feces does not necessarily mean that coccidiosis is present, nor does their absence necessarily mean that it is absent, since oocysts may not be produced until 2 or 3 days after the first signs of disease appear.
Treatment: Little is known about treatment of coccidiosis in pigs. Alicata and Willett (1946) found that when 1 g sulfaguanidine per 10 lb body weight was administered to pigs daily with their feed for 7 or 10 days beginning 2 days before experimental infection with 20 to 30 million sporulated oocysts of E. debliecki and E. scabra, very few if any oocysts were produced and the pigs did not become ill. Similar treatment with sulfaguanidine for 3 days beginning on the 2nd day of oocyst discharge reduced the numbers of occysts produced and the period of discharge. Presumably other sulfonamides would also be of value.
Prevention and Control: Sanitation will prevent coccidiosis in swine. Pens should be cleaned frequently, overcrowding should be avoided, and pigs should be raised under conditions which prevent them from eating many infective oocysts.