Equine Infectious Anemia Virus
of Equine Infectious Anemia virus occurs almost exclusively via a
mechanical vector containing contaminated blood or blood product
most common vector are biting insects (mouthparts) that transfer the
infection from one contaminated horse to an uninfected horse.
Other sources of transmission include:
It is also notable that EIA is not shed via urine or saliva (2)
- Intrauterine infection (resulting in abortion) - infected foals often die within 2 months
- Infected milk from the dam to the nursing foal (2)
- Seminal fluid from an infected stallion (introduced via a vaginal tear)
- The use of contaminated needles or improperly sterilized surgical instruments (1,4)
1 of every 6 million flies is likely to become a vector (2).
Of these insects, the most common mechanical vectors include the stable
fly (Stomoxys calcitrans) and the biting flies: horse flies
(Tabanus spp. and Hybomitra spp.) and deer flies (Chrysops spp)
(2,3,5). As the fly bites one horse, the horse's reaction to the
bite will interrupt the fly's feeding, and will therefore re-attempt to
bite the same horse, or will then move on to bite another horse with
its newly infected mouthparts.