Systemic and enteric salmonellosis in calves

Differential regulation of enteric and systemic salmonellosis by slyA.

Mutation of slyA, which reduces Salmonella typhimurium virulence in mice, caused only minor attenuation of S. typhimurium virulence in orally inoculated calves. This correlated with modest reductions in intestinal invasion and enteropathogenic responses in bovine ligated ileal loops. slyA appears to regulate virulence genes involved in systemic, but not enteric, salmonellosis.

Salmonella pathogenicity island 2 influences both systemic salmonellosis and Salmonella-induced enteritis in calves.

We have used signature-tagged mutagenesis to identify mutants of the host-specific Salmonella enterica serotype Dublin which were avirulent in calves and/or BALB/c mice. A mutant with a transposon insertion in the sseD gene of Salmonella pathogenicity island 2 (SPI-2), which encodes a putative secreted effector protein, was identified. This mutant was recovered from the bovine host but not from...

Cross-protection against a human enteric coronavirus and a virulent bovine enteric coronavirus in gnotobiotic calves.

A group 2 human coronavirus designated HECV-4408 was isolated from a child with acute diarrhea and is antigenically and genetically more closely related to bovine coronavirus (BCoV) than to human coronavirus OC43 (X. M. Zhang, W. Herbst, K. G. Kousoulas, and J. Storz, J. Med. Virol. 44:152-161, 1994). To determine whether HECV-4408 infects gnotobiotic calves and induces cross-protective immunit...

Coronavirus in Gnotobiotic Calves Coronavirus and a Virulent Bovine Enteric Cross-Protection against a Human Enteric

Prevention of experimentally induced enteric colibacillosis in newborn calves.

Severe enteric colibacillosis, characterized by profuse watery diarrhea, dehydration, apathy, hypothermia, and inability to stand, was produced in seven of eight newborn, colostrum-fed calves from nonvaccinated dams after oral challenge of calves with 10(11) viable cells of Escherichia coli strain B44. Twenty-nine of 32 calves from dams vaccinated with various preparations of E. coli strain B44...