Plague: Infections of Companion Animals and Opportunities for Intervention

Abstract

Plague is a zoonotic disease, normally circulating in rodent populations, transmitted to humans most commonly through the bite of an infected flea vector. Secondary infection of the lungs results in generation of infectious aerosols, which pose a significant hazard to close contacts. In enzootic areas, plague infections have been reported in owners and veterinarians who come into contact with infected pets. Dogs are relatively resistant, but can import infected fleas into the home. Cats are acutely susceptible, and can present a direct hazard to health. Reducing roaming and hunting behaviours, combined with flea control measures go some way to reducing the risk to humans. Various vaccine formulations have been developed which may be suitable to protect companion animals from contracting plague, and thus preventing onward transmission to man. Since transmission has resulted in a number of fatal cases of plague, the vaccination of domestic animals such as cats would seem a low cost strategy for reducing the risk of infection by this serious disease in enzootic regions.

Does the Plague Still Threaten Us?

“…Importing and trade of animals require special attention. These growing and profitable activities are responsible for the occurrence of plague both in endemic and non-endemic areas, putting staff and customers at risk 9 . Therefore, plague must be considered when acute febrile diseases are diagnosed in the most diverse mammal species, which exposes owners, veterinarians, and assistants to a high-risk situation 3,9 .…”

The natural history and incidence of Yersinia pestis and prospects for vaccination

“…This sets the experimental rF1/V vaccine apart from the previous killed wholecell vaccines, which have been demonstrated to protect animal models against injected challenge with Y. pestis, but which cannot protect against inhaled challenge (Williamson et al, 1997). The protective efficacy achieved with rF1/V in animal models is equivalent to that afforded by live attenuated vaccine strains, such as EV76, but without the risks inherent to a live vaccine (Oyston & Williamson, 2011 Protecting against plague lack of the V antigen in the KWCV formulations, which contained effective quantities of the F1 antigen only (Williamson et al, , 2000, whereas live attenuated vaccines contain both F1 and V antigens .…”

Delayed diagnosis of fatal pneumonic canine plague: clinical and pathologic features in two naturally infected Colorado dogs

“…When dogs do become clinically ill with plague, they typically present with the bubonic or septicemic forms [8,10], which have a relatively low risk of direct transmission. Domestic dogs have been occasionally implicated in the transmission of plague to humans through carriage of infected fleas resulting in the bubonic form of disease [15,16].…”