The prevention and control of West Nile fever

Vaccinate for West Nile fever before the mosquito season starts, says Dr Mac. This is the key to prevention.

- Dr Mac

Most horse owners in South Africa know that they have to vaccinate against African horse sickness (AHS), but vaccination against West Nile fever (WNF), which is a zoonosis and can infect humans, is not compulsory. A deactivated equine vaccine called Duvaxyn R has been available for the past few years. However, this year, a new recombinant canarypox vaccine called Proteq West Nile has been introduced.

SIGNS OF THE DISEASE

WNF is caused by a virus and transmitted to horses, people, and birds by mosquitoes. It can be fatal in all three species.

In horses, WNF mimics AHS, as horses may swell above the eyes. However, the main difference is that with WNF, infected horses may also stumble, tremble, and suffer from partial blindness. Some horses may even become partially paralyzed and go down. It is typical for horses to first become paralyzed in their hindquarters, and thus struggle to rise. About 40% of horses that demonstrate such severe symptoms die.