Viruses Genomes - ENCEPHALOMYOCARDITIS VIRUS

Encephalomyocarditis virus (EMCV) is a widely distributed picornavirus belonging to the Cardiovirus genus. The picornavirus infects many animal species including pigs, rodents, cattle, elephants, raccoons, marsupials, and primates such as baboons, monkeys, chimpanzees, and humans.

The main reservoir host is the rat although mice may also spread it passing the virus to other species through fecal-oral transmission. EMCV infects and causes disease in a wide range of vertebrate animals but pigs appear to be the most susceptible domesticed species. The virus is world-wide but differs in pathogenicity and virulence in different countries and regions. One strain, type A, causes reproductive problems, a second strain, type B, causes heart failure. EMCV is endemic in many pig populations. The virus causes acute myocarditis and sudden death in preweaned pigs, whereas transplacental infection of sows causes fetal mummification, abortion, stillbirth, and neonatal death

Even though no detailed pathogenetic studies have been performed to determine the porcine cells supporting EMCV replication and possible persistence, the heart, liver, and kidney have been shown to have higher EMCV titers than blood, suggesting that EMCV replicates in these organs. Studies indicate that EMCV can cause interspecies infections, making it an important zoonotic agent.

The EMC viruses have rarely been recognized as the cause of human illness, and the severe myocarditis and acute fatal infections seen in many other species have not been reported in humans. Serosurveys indicate that human EMCV infections are relatively common in certain areas of the world, but most cases are asymptomatic or unrecognized. Clinical signs in humans have varied from mild febrile illness to severe encephalomyelitis.

Recent advances toward using pig tissues as a means of overcoming the acute shortage of transplantation tissues and organs for humans have made it necessary to determine the risk of transmitting zoonotic viruses from pigs to humans or vice versa. Porcine cells, tissues, and organs are the primary animal tissues being considered for human transplantation because of similar anatomical and physiological features in humans and pigs, ready availability of the species, and relative ease of breeding pigs.

EMCV has no treatment, however, there is an apparently effective inactivated vaccine available in the United States. The most effective method of controlling EMCV is to control the rodent population.

References:

http://www.thepigsite.com/Tips/Default.asp?Display=72
http://virology.wisc.edu/acp/AboutACP/papers/PdfFiles/Brewer-01.pdf
http://www.aazv.org/idn_emcv.htm
http://www.addl.purdue.edu/newsletters/1999/fall/ecmv.shtml