Development of a Histophilus somni vaccine to prevent histophilosis in beef cattle

Project Team: Jose Perez-Casal

Histophilosis is the largest cause of mortality in fall placed calves in feedlots in Western Canada. Histophilus somni causes septicemia, which can result in multiple manifestations of the disease including myocarditis, pericarditis, pleuritic, bronchopneumonia, arthritis and infectious thromboneningoencephalitis (ITME).

Most H. somni vaccines currently on the market were developed from strains of the bacteria isolated during the 1970s to address the nervous form of the disease (ITME). These vaccines do not have clinical efficacy against myocarditis, pericarditis, pleuritic or arthritis caused by the bacteria. Our research is focused on isolating and characterizing more recent strains of H. somni that cause the various septic forms of histophilosis currently observed in beef cattle, and to develop a new vaccine for H. somni that will prevent the various septic forms of the disease, in particular, myocarditis.