Salmonellosis in Peruvian guinea pig production : a study to evaluate the prevalence of salmonella spp and importance of the disease

Abstract: In Peru guinea pigs are raised for meat production and salmonellosis is considered as a major problem. Studies have detected salmonella in animals with enteritis and pneumonia. Salmonellosis exists both in an acute and a chronic form. In the rural areas the diagnosis is made according to clinical signs and macro pathological findings at autopsy. The major systems applied for the guinea pig production are often classified as family, family-commercial and commercial. These systems differ in number of animals and how industrialised they are. During the last years the demand of meat and subsequently the production of guinea pigs have increased. Improvements of programs for breeding and education have increased the size of the animals and their welfare conditions. Salmonella spp, the etiological agent of salmonellosis, is a gram-negative bacterium that can cause disease in most animal species including guinea pigs, cattle, pigs and humans. The signs vary between species but enteritis is common. In guinea pigs signs such as diarrhoea, ascites, abortions, paralysis of hind limbs and increased mortality are seen. But the bacteria can also exist in asymptomatic carriers. The diagnosis of salmonellosis is made mainly by bacteriological culture methods but also molecular methods are available today. This study was performed to investigate the prevalence of salmonella in guinea pig in the Mantaro valley in Peru as a way to evaluate the importance of the disease. Composite faecal samples as well as rectal swabs were taken from a total of 224 randomly selected guinea pigs from farms of different size The samples taken from animals of different gender and age , were cultivated according to standard bacteriological methods using buffered peptone water (BPW) and selective medias (Rappaport-Vassiliadis-Salmonella enrichment broth (RVS) and Xylose Lysine Deoxycholate agar (XLD)). Suspected colonies were biochemically tested using API10S. In contrast to previously reported information no salmonella was found in either the composite samples or the rectal swab samples. The reason for this discrepancy is questioned due to unforeseen methodological challenges. However, the study also indicates that salmonellosis may be over diagnosed as a problem among guinea pigs in Mantaro valley.