MEMPHIS, Tenn. (AP) — State agriculture officials are advising horse owners in west Tennessee to vaccinate their livestock due to the threat of mosquito-borne illnesses.

Officials say horses in Dyer and Gibson counties recently have tested positive for West Nile virus and Eastern Equine Encephalitis, respectively.

State veterinarian Charles Hatcher says record heat this fall "has allowed mosquitoes to endure." He says it's critical that livestock are current on annual vaccinations "for year-round protection."

Sick horses cannot directly infect people with the diseases. Mosquitoes are responsible for transmission, and resulting viruses can be fatal. There is no vaccine for people, but the West Nile and Eastern Equine vaccines are particularly effective to protect horses against infection.

In addition to vaccinating livestock, officials say residents should eliminate standing water sources where mosquitoes breed.