Author : Ly Thi Lien Khai

Summary : Neonatal colibacillosis in pigs is one of the most serious problems in swine production. This study was conducted to determine the occurrence of K88, K99, 987P E. coli causing neonatal colibacillosis in suckling pigs in some selected pig farms in Cantho and Ho Chi Minh cities in Vietnam. Rectal swabs were collected from 30 normal and 30 piglets with diarrhea. The piglets were divided into two age groups: one week old and two to three weeks old. From each farm twelve samples were collected consisting of three samples each from the normal and diarrheic piglet group. By colonial morphology and biochemical tests, E. coli was identified. Fimbrial antigens were determined by coagglutination test while the production of heat-labile (LT) and heat-stable (STa) enterotoxins were detected by the rabbit ligated intestinal loop test and suckling mouse assay, respectively. The K88 antigen was associated with hemolytic E. coli colonies. Organisms which possessed K88 antigen were isolated from 14.3% diarrheic piglets and from 24% of normal piglets. Those which possessed the K99 antigens were isolated from 42.9% of diarrheic piglets and from 43.2% of normal piglets and those which possessed the 987P antigens were isolated from 2.4% of diarrheic piglets. Most cases of diarrhea among the five swine farms studied occurred within three weeks of age, and were associated with K88, K99, and 987P E.coli (P<0.01). Meanwhile the pattern of occurrence of E. coli K88, K99, and 987P from normal piglets among the farms was not signficantly different. The distribution of E. coli bearing the K88, K99, and 987P antigens detected among the five farms from piglets with or without diarrhea was not significantly different. Multiple infections (associated with K88) occurred in 5.9% of K99 positive cases. The prevalence of diarrhea associated with E.coli K88 and K99 organisms was highest in two week-old piglets and lower in older piglets.