Salmonellosis in pigmy hogs (Sus salvanius)--a critically endangered species of mammal.

The pigmy hog (Sus salvanius) is the smallest and the rarest wild suid in the world. This species is on the verge of extinction and the World Conservation Union has rated it among the most endangered of all mammals. This paper reports the investigation into an outbreak of salmonellosis among captive pigmy hogs at the Research and Breeding Centre of the pigmy hog conservation programme, Guwahati, Assam, India. Of 75 pigmy hogs (38 males and 37 females) maintained at the Centre, seven (9.3%) died within five days. The causative organism associated with the outbreak was identified as Salmonella Typhimurium (syn. S. enterica serovar Typhimurium). All the isolates of S. Typhimurium belonged to phage type DT193. The isolates harboured multiple plasmids. Five isolates harboured four (65.0 MDa, 4.2 MDa, 3.0 MDa, 1.3 MDa), while two isolates carried three plasmids (65.0 MDa, 4.2 MDa, 3.0 MDa). All strains showed resistance to amikacin, ampicillin, streptomycin and sulfamerazin; five strains were resistant to oxytetracycline and trimethoprim. All the strains were sensitive to chloramphenicol, ciprofloxacin, enrofloxacin and gentamicin. All seven isolates of S. Typhimurium were found to harbour stn, sopB and pefA genes. However, none of them was found to carry sefC and sopE genes.