(last update: March 2015)

In this report, the Italian Horse Protection Onlus would like to explain some aspects of Equine Infectious Anaemia which can cause confusion and subsequently serious risks to life of many horses who don’t present any clinical signs of the disease.

Equine infectious anaemia (EIA) is a viral disease of horses. Its symptoms include bouts of high fever, anaemia, weight loss and reduction of the performance. In sporadic cases, sudden death  can occur. Theoretically all equids are subject to the equine infectious anaemia.

The disease can be transmitted by blood-sucking insects or due to the use of infected veterinary tools (the only ascertain event of this kind in Italy happened in 2006, due to the use of contaminated blood products).
The tests currently used to determine the positivity to the disease (ELISA and AGID aka Coggins), reveal only the occurred contact between the animal’s immune system and the virus. According to the Italian National Veterinary Association, “positive horses present a viraemia level generally insufficient for the transmission of the disease via blood-sucking insects”( ANMVI, 25 novembre 2009), thus positive specimens are not, as general rule, contagious. Really sick animals are different matter.

According to the IZSLT (Istituto Zooprofilattico Sperimentale of Lazio and Tuscany, currently the national centre of reference for this disease), over the test period 2007-2011, only 1.479 horses were found positive, out of the 1.080.043 animals examined. This represent only the 0,14%. The proportion of positive results among mules was higher, with 736 positive results out of 12.000 subjects tested. Only 35 cases were recorded in donkeys.

Percentages are, therefore, extremely low, in particular with regard to horses and donkeys. But the information which most stands out is that in all the years of studies at the infectious diseases Centre of Reference for Equine Infectious Anaemia, is that there have been no documented cases of the full-blown disease itself; according to the report of Dr Marcello Sala (from Ministry of Health), we are talking only of horses with a positive antibody result, in whom the presence of the virus is “generally insufficient to infect other equines” (as was stated by ANMVI, the Italian Veterinarian National Association, in previous bulletins).

And this is not all: a very interesting clarification emerged during the conference (Rome, 2011) regarding the manner of infection, in that the true risk lies in a failure to properly sterilise veterinary instruments such as syringes, needles and other surgical equipment.

According to Dr Issel, Gluck Equine Veterinary Centre of the University of Kentucky USA, the proposition of contagion via insects remains basically a matter of theory: a horsefly which, for example, sucks blood from an EIA-positive, horse will conserve in its oral apparatus such an infinitesimal amount of that blood as to be insufficient to infect a healthy animal (assuming the horsefly moves from one horse to another). In any case, in the horsefly’s ‘mouth’ the virus dies within an extremely short time, both facts rendering infection between horses via insect carriers highly improbable.

Thus it is perhaps more accurate and more sensible to say that the real risk of infection is not via insects but rather human error: the tiny amount of fresh blood remaining in a hypodermic needle, as opposed to that remaining in the mouth of a horsefly, is much more likely to infect another horse.

According with the current laws, in Italya  those horses who are positive to the blood test must be separated from others, because situations of increased stress such as a working life, exposure to other illnesses and the need for treatments such as those involving cortisones, could cause the reactivation of Equine Infectious Anaemia and increase the quantity of virus in the equine’s blood stream. This circumstance never occurred in any of the horses seropositive hosted by us

LEARN MORE:
EIA - IHP Report
EIA - IHP VIDEO
The Saphira Case: IHP-FNOVI meeting - 20 February 2015
Saphira, killed by ignorance and without scruple, October 2014
Equine Infectious Anaemia, proceedings of the conference held on 1 October 2012, Rome
2011, January 25th. - Letter from rocket’s "mom"
2011, January 24th. - EIA, request of confirmation to Honorable Francesca Martini
2011, January 18th. - Let’s free Rocket!
2011, January 14th. - Rocket, Infectious Anemia and logic?
2011, January 9th. - Rocket, the tale of an injustice
Video: Rocket, una cavalla da ascoltare
Video: Rocket quando era libera
Interview with the owner of Solanos - April 2010


Bibliography:

- Leroux C., Cadorè J.L., Montelaro M.C. Equine Infectious Anaemia Virus (EIAV): What has HIV’s country cousin got to tell us? Vet. Res. 35: 485-512, 2004.

- Timoney J.F., Gilledpie J.H., Scott, F.W. and Barlough, J.E.: Microbiology and infectious diseases of domestic animals, 8th edition (1988) Comstock Pub. Co., Ithaca NY.

- Harrold S.M., Cook S.J., Cook R.F., Rushlow K.E., Issel C.J., Montelaro R.C.: Tissue Sites of Persistent Infection and Active Replication of Equine Infectious Anaemia Virus during Acute Disease and Asymptomatic Infection in Experimental Infected Equids.

- Issel, C.J. and Coggins, L.: Equine Infectious anaemia: Current Knowledge. J.A.V.M.A. 174:727-733, 1979.


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