Encephalomyocarditis (EMCV)

Test code: S0069 - Ultrasensitive qualitative detection of encephalomyocarditis virus by reverse transcription real time polymerase chain reaction

Encephalomyocarditis virus (EMCV) is a single stranded picornavirus belonging to the cardiovirus genus that infects many animal species including pigs, rodents, cattle, elephants, raccoons , marsupials, baboons, macaques, chimpanzees and humans . Rats and mice are the natural hosts of the virus, but pigs are the most commonly and severely infected domestic animals. The ability of this virus to cause interspecies infections had led to numerous outbreaks in zoos in Australia and the United States (Reddacliff et al., 1997; Wells and Gutter, 1989). These outbreaks involved multiple animal species including lemurs, squirrels, macaques, mandrills, chimpanzees, hippopotami, kangaroos and possibly humans. Humans infected with this virus had been shown to have fever, neck stiffness, lethargy, delirium, headaches, or vomiting (Gajdusek, 1955; Murname, 1981). In recent years, there has been renewed interest in this virus, especially in pig-to-human transmission, because of advances in xenotransplantation as a means of overcoming the acute shortage of transplantation tissues and organs for humans.

In primates, encephalomyocarditis virus can cause necrotizing and interstitial myocarditis in gibbons and owl monkeys. Infected rhesus monkeys can develop encephalomyelitis and paralysis but they may recover.

In the past, diagnosis of EMCV was based on virus isolation and identification. This method is time-consuming and the virus is difficult to isolate from infected animals. Experimental EMCV infection in pigs showed that virus could no longer be isolated after 3 days post-infection (Foni et al., 1992), but the virus may continually persist for a long period in infected pigs without any clinical signs (Billinis et al., 1999). Confirmation of this pathogen has relied upon the development of circulating antibody, but this diagnostic approach is not reliable because a recent study in pigs has shown that some infected pigs may not develop antibodies against EMCV (Brewer et al., 2001).

EMCV detection by PCR is the most rapid, sensitive and specific method for the diagnosis of this infection. PCR methodology can reduce the frequency of false negative diagnoses of this virus.

Utilities:

• Confirm the disease causing agent
• Ensure that animal groups or populations are free of EMCV
• Early prevention of spread of this virus among a population
• Minimize human exposure to this virus

References:
Reddacliff, L. A., P. D. Kirland, W. J. Hartley, and R. L. Reece. (1997) Encephalomyocarditis virus infections in an Australian zoo. J. Zoo Wildl. Med. 28:153-157.
Wells, S. K., and A. E. Gutter. (1989). Encephalomyocarditis virus: epizootic in a zoological collection. J. Zoo Wildl. Med. 20:291-296.
Gajdusek, C. (1955). Encephalomyocarditis infection in childhood. Pediatrics 16:819.
Murname, T. G. 1981. Encephalomyocarditis, p. 137-147. In G. W. Beran (ed.), CRC handbook series in zoonoses, section B, vol. 2. Viral zoonoses. CRC Press, Boca Raton, Fla.
Foni, E., Barigazzi, G., Sidoli, L., Marcato, P.S., Sarli, G., Della Salda, L. and Spinaci , M. (1993). Experimental Encephalomyocarditis virus infection in pigs. J. Vet. Med. 40:347–352.
Billinis, C., Paschaleri-Papadopoulou, E., Psychas, V., Vlemmas, J., Leontides, S., Koumbati, M., Kyriakis, S.C. and Papadopoulos , O. (1999) Persistence of Encephalomyocarditis virus (EMCV) infection in piglets. Vet. Microbiol. 70:171–177.
Brewer, L.A., Lwamba, H.C., Murtaugh, M.P., Palmenberg, A.C., Brown, C. and Njenga, M.K.(2001) Porcine encephalomyocarditis virus persists in pig myocardium and infects human myocardial cells. J.Virol. 75:11621-11629

Specimen requirement: 1 ml whole blood in EDTA (purple top) or ACD (yellow top) tube, or 1 ml plasma, serum or tissue, shipped overnight at room temperature; or 1 ml frozen plasma, serum or tissue, shipped frozen.

For specimen types other than those listed here, please call to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative reverse transcription real time PCR

Normal range: Nondetected