Readers Respond

HEV in Texas 

May I amplify and update the “Observatory” item that appeared in your August 2010 issue, page 8: “Fatal hepatitis E reported in Texas.”

Hepatitis E virus (HEV), although primarily found in other countries, does occur in the United States. In 1996, case reports of HEV in the United States predominantly involved immigrants or visitors traveling to endemic countries.¹ In Asia and Africa, HEV reportedly had become the main cause of symptomatic, enterically transmitted hepatitis and was responsible for large epidemics affecting adults.² In fact, it accounted for the majority of cases of acute viral hepatitis found among young and middle-aged adults.³ In 1997, Kwo and associates⁴ reported the first case of acute HEV in the United States by a new isolate found in a patient hospitalized for acute hepatitis without travel outside the United States. In follow up studies, a variant of HEV, designated HEV US-1, was identified.⁵ Since HEV was thought to cause the majority of epidemic hepatitis and acute, sporadic hepatitis in developing countries,⁶ the finding of a non-Burmese or Mexican strain presented new significance for this virus in the United States. In a recent interview, Mushahwar³ reported that HEV is the sole member of the genus Hepevirus in the family of Hepeviridae. It is transmitted predominantly by the fecal-oral route and has a mortality rate in young adults and pregnant women of 0.5-3% and 15-20%, respectively.⁷

There are four major genotypes and a single serotype. Aggarwal and Naik⁷ reported that genotypes 1 and 2 have been linked exclusively to humans, but genotypes 3 and 4 have been found in pigs as well as humans. Although HEV is typically an acute infection, genotype 3 HEV has caused chronic infections in immunocompromised patients.⁷ Also, swine HEV characterization shows a close relationship to human HEV, and it can be transmitted zoonotically from domestic swine, deer, and wild boars. In 2000, Borgohaim et al.⁸ reported the presence of acute pancreatitis associated with acute HEV infections. In this report an 18-year-old male presented with acute hepatitis symptoms, which included severe abdominal pain and an enlarged pancreas revealed by ultrasound. Although the exact cause of pancreatic injury was unclear, the report pointed out that severe abdominal pain during the early stages of hepatitis should alert the clinician to the possibility of associated pancreatitis.⁸

By 2005, the coincidence of acute pancreatitis with HEV was well documented, along with similar organ involvement in Hepatitis A and B cases.⁹ In another study from 2007, acute pancreatitis was reported to occur in about 5.65% of patients with acute viral hepatitis.¹⁰

In summary, there are HEV strains in the U.S. that are causing infections such as the US-1 strain and those from zoonotic sources. Clinicians should be advised that if acute hepatitis A and B have been ruled out, the potential for HEV should be considered. Acute pancreatitis can occur along with these acute hepatitis infections and should be considered if a patient presents with severe abdominal pain.

— David L. Smalley, Ph.D., MSS, BCLD
Public Health Laboratory Director
Galion Community Hospital
Tennessee Department of Health
Division of Laboratory Services
Nashville, TN

References

1. Smalley DL et al. Hepatitis E virus infection in an immigrant to the United States. Southern Med. J. 89(10):994, 1996.
2. Pavio N et al. Hepatitis E: a curious zoonosis. Front Biosci. 1(13):172, 2008.
3. Mushahwar IK. Hepaitits E virus: molecular, virology, clinical features, diagnosis, transmission, epidemiology, and prevention. J. Med. Virol. 80(4):646, 2008.
4. Kwo PY et al. Acute hepatitis E by a new isolate acquired in the United States. Mayo Clin. Proc. 72:1133, 1997.
5. Schlauder GG et al. The sequence and phylogenetic analysis of a novel hepatitis E virus isolated from a patient with acute hepatitis reported in the United States. J. Gen. Virol. 79:447, 1998.
6. Krawczynski K et al. Hepatitis E. Infect. Dis. Clin. North Amer. 14(3):669, 2000.
7. Aggarwal R and Naik S. Epidemiology of hepatitis E: current status. J. Gastroenterol. Hepatol. 24(9):1484, 2009.
8. Borgohain S et al. Acute pancreatitis associated with acute hepatitis E virus infection. J. Indian. Acad. Clin. Med. 1(3): 283, 2000.
9. Jaroszewicz J et al. Acute hepatitis E complicated by acute pancreatitis: a case report and literature review. Pancreas 30(4):382, 2005.
10. Jain P et al. Acute pancreatitis in acute viral hepatitis. World J. Gastroenterol. 13(43)5741, 2007.

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