TEXAS VET NEWS By Dr. Bob Judd, DVM and the Texas Farm Bureau Texas Farm Bureau Radio Network

The last couple of programs I have talked about vaccinating for equine influenza and equine herpes virus and the fact that the vaccines may not prevent 100% of disease.  Today I am going to talk about West Nile virus vaccine as this is another vaccine routinely recommended for all horses in Texas.  As you probably know, West Nile virus is transmitted by mosquitos and the main source of the virus is birds.  All of the West Nile vaccines available at this time have been shown to be between 80 and 90% effective at preventing the disease, and the vaccines appear to be effective for up to 1 year.  However, in some horses, studies showed the vaccine titer decreased after 6 months, so in areas with lots of mosquitos and exposure to the virus, it may be a good idea to vaccinate twice yearly with West Nile vaccine. A major concern when the West Nile vaccine first came on the market was an Internet-reported problem in pregnant mares.  The vaccine was blamed for everything from abortions to deformed foals to colic.  However, a study has since been performed on almost 600 pregnant mares and no abnormalities were found after vaccinating for West Nile. 

Another vaccine I want to mention briefly is for Potomac horse fever.  This is a bacterial disease that causes fever and diarrhea and we rarely see this disease in Texas as it is usually seen in the northeast.  Although there is a vaccine available for this disease, the vaccine has not been shown to be very effective and is not recommended in most cases.  Next program I am going to continue with the discussion of equine vaccines so be sure and tune in so you can be familiar with the recommended vaccines for your horses.

Date Published: 7/6/2009 9:47:00 AM