Yersinia species isolated from sheep with enterocolitis

Abstract

In 40 submissions to the Regional Veterinary Laboratory (RVL) Wagga Wagga from sheep in southern New South Wales from 1981 to 1989, 53 isolates of Yersinia sp were recovered from 45 sheep in 37 flocks. Of 53 isolates, 26 were identified as Y. pseudotuberculosis, 20 as Y. enterocolitica, 5 as Y. intermedia and 2 as Y. frederiksenii. Twelve isolates of Y. pseudotuberculosis tested in the slide agglutination test all belonged to serotype III. The 20 Y. enterocolitica isolates were categorised biochemically as biotype 5 strains and, of 6 isolates serotyped, all belonged to serogroup 2,3. Outbreaks of yersiniosis were most common in late winter and early spring and affected flocks often had experienced a change in husbandry. Infection with Yersinia sp was associated with diarrhoea, illthrift and mortality. At necropsy, congestion and occasionally thickening of the intestinal mucosa were observed in affected sheep. Gastrointestinal nematodiasis and coccidiosis often were concurrent findings. The characteristic histological lesion in sheep infected with Y. pseudotuberculosis was acute segmental suppurative erosive enterocolitis. There were no lesions consistently associated with Y. enterocolitica, Y. intermedia or Y. frederiksenii.

Caprine Enteritis Associated with Yersinia pseudotuberculosis Infection

“…Yersiniosis takes a variety of clinicopathological forms: fulminant, subacute and chronic. Fulminant Yersinia infection causes fibrinous or fibrinonecrotic enteritis [1,8,20], the subacute infection produces microabscesses in the intestinal mucosa, and the chronic infection is accompanied by villous atrophy and intestinal glandular hyperplasia [13]. The present intestinal lesions seem to have the characteristics of subacute to chronic infections.…”

“…Although the exact origin of the present infection remains unknown, there might have been indirect contacts between the goats and cows in the dairy-producing area via feral birds or other animals. Alternatively, reservoirs maintaining infection might have been present in the caprine herd, as pointed out previously [13,15]. Further investigations on the origin of the infection should be performed for the purpose of prophylaxis of the disease.…”

“…Stress factors are generally thought to be necessary to precipitate the disease. The factors include cold, starvation, poor feeding, parasite infection, transport and pre-existing gastrointestinal mucosal lesions [2,7,12,13]. There are few reports on epidemic yersiniosis in caprine herds in Japan, although generalized infection with Y. pseudotuberculosis serotype I was described in a goat [11].…”

“…The organisms are divided into the serotypes I to VI based on the somatic O antigenic structure, and serotype III has been found to be associated with the disease in a wide range of ungulate species, such as sheep, goats, pigs [13,15,16] and less frequently cattle [4,14]. Stress factors are generally thought to be necessary to precipitate the disease.…”

“…Y. pseudotuberculosis, a gram-negative and aerobic or facultatively anaerobic coccobacillus, is an infrequently incriminated pathogen responsible for enteritis and septicemia in various species of mammals and birds with seasonal prevalence in the cooler months [12]. The lesions are characterized by microabscesses with bacterial colonies in the intestine and mesenteric lymph nodes, and often in visceral organs [1,13,15,18]. The organism is also associated with mastitis [5,9] and abortion [10,21].…”