Studies on piglet diarrhoea associated with enterotoxigenic escherichia coli and its control by vaccination

Abstract

Piglet neonatal diarrhoea occured in all the piggeries studied in Indonesia. Field studies demonstrated the prevalence of diarrhoea in all piggeries were at range from 13.4% to 43.7% with and average 24.7%. The majority of piglets with diarrhoea were in the first 2 weeks of life. Mortality of piglets were at rates between 12.2% to 31.6% with an average 17.9%. The distribution of piglet mortality preceded by diarrhoea recorded in an intensive study in a piggery G for a seven week period showed a high positive correlation with diarrhoea (r² = 0.79; P<0.01), thus confirming that diarrhoea has a significant influence on mortality during the neonatal period. Piglet neonatal diarrhoea was found to be associated with enterotoxigenic Escherichia coli (ETEC) expressing either the 987P, F41, K99 or K88 fimbrial antigen. E. coli expressingfor more than one fimbrial antigen K88, K99 and K99 F41 were also found in a limited numbers. E. Coli 987P predominated, all were non haemolytic, majority were associated with O-group 20, less frequently with either 0, or O₉ or O ₁₄₁ E. coli F41 isolates were non haemolytic and associated with either O-group 101 or O-group 9. E. coli K99 isolates were associated with either O-group 20,64, or O-group 101. E. coli K88 isolates were haemolytic and associated with either O-group 108, 138, 149 or 157. Attempts to control piglet neonatal diarrhoea associated with ETEC by antibiotic treatments on farm were reported unsuccessful. Antibiotic sensitivity assays of E. coli isolates bearing either K88, K99, F41 or 987P fimbrial antigen confirmed a high level of multiple antibiotic resistant between 4 to 6 antibiotics, including streptomycin, ampicillin, oxytetracycline, kanamycin, neomycin, trimethoprim and suphamethoxazole and sulphonamides. E. coli K99 showed higher level resistant up to 9 of antibiotics tested. As an alternative to chemotherapy with antibiotics, a vaccination strategy was investigated. An inactive multivalent ETEC vaccine containing K88. K99, F41 and 987Pfimbrial antigens and somatic antigens of O-group 9,20,64,108,138, 149 and 157 was prepared. Field trials to control piglet neonatal colibacillosis were conducted in some piggeries. The local field isolate vaccine was compared to a similar commercial vaccine acquired from abroad which content 5 important fimbrial antigens. Pregnant sows were injected intramuscularly with 2 ml of vaccines 6 weeks and again 2 weeks before expected date of farrowing. Piglets born from vaccinated and unvaccinated sown were allowed to suckle their own mothers. Pregnant sow vaccination produced a highly significant reduction diarrhoea and mortality rates.