The Paper- Transcription

Summary

During a severe outbreak of clinical salmonellosis in an experimental guineapig [sic] colony, a new strain of Salmonella was isolated and identified. This new serotype, with the antigenic structure 1,3, 19 : Z38: e, n, Z15, for which the name Salmonella ochiogu has been suggested, caused both an enteric and systemic infection in the animal colony. During the outbreak a total of 127 animals died (26.9%). All ages of animal were affected. Treatment with oral tetracycline was successful when combined with strict hygienic measures.

Materials and methods

History of outbreak

The epidemic of severe clinical salmonellosis occurred in a guineapig colony of about 472 indigenous individuals. The animals were bred on straw deep litter, fed ad libitum on pelleted food plenty of clean water and green vegetables. Clinical signs observed in the adults included: a) swollen abdomen with pasting of the anal region with scoury faeces; b) rough and dull hair coat, animals generally inappeten, severely depressed and some moribund; c) severely sick animals seen curled with raised haircoat, and not moving even when stimulated; d) some exhibiting jerky and rapid respiratory movements, and with body temperatures of >40 C. Death occurred usually 24-48 h after exhibition of the clinical signs. For the newly born and weaners, death was very sudden without any premonitory signs. 

A few days before the outbreak the animal attendants reported seeing wild rats visiting the animal house for food and water through cracks and holes in the house. 

Collection of specimens

Samples for microbiological examination included heart blood, abdominal fluid and scrapings from the intestinal linings of both dead and recumbent animals. Staining by Gram’s method was carried out on the samples adopting a standard procedure described by Cowan & Steel (1979). Also samples of the animal bedding materials, water, feed, and ‘hand washings’ of the attendants were submitted for bacteriological examination.

Blood for haematological analysis and cell counts were obtained from recumbent animals by cardiac puncture using sterile needles and syringes. 

Severely sick animals were humanely killed and autopsied while others were quarantined and given tetracycline in drinking water at a concentration of 4-5 g/l for periods ranging from 7-10 days, a level lowe enough not to be toxic to the tsetse flies that would feed on these animals. Recovery was remarkable for some animals, although some in the chronic stage of the infection died...