Monthly Archives: May 2016

Mikhail Balayan and the Bizarre Discovery of Hepatitis E Virus

There have been several instances in which medical researchers, for the sake of mankind, allowed themselves to be infected with a potentially deadly pathogen. A well known example involved the discovery that the Aedes aegypti mosquito is the vector for yellow fever (1). Here we consider a less known and slightly bizarre example in which Mikhail S. Balayan, of the Russian Academy of Medical Sciences in Moscow, discovered the hepatitis E virus.

But first, hepatitis refers to an inflammatory disease involving the liver. Four unrelated viruses, hepatitis A, hepatitis B, hepatitis C, and hepatitis E viruses cause epidemic viral hepatitis (see Aside 1). Hepatitis E was initially identified in 1980 as a non-A, non-B infectious hepatitis. The differences between hepatitis A, B, and E virus infections are as follows. Hepatitis A and hepatitis E are similar, insofar as the etiologic agent of each usually gives rise to an acute (i.e., self-limiting) infection and illness. In contrast, hepatitis B and hepatitis C viruses usually give rise to persistent infections that may lead to chronic hepatitis, cirrhosis, and liver cancer. The mortality rate for hepatitis E is generally “only” about 1% to 2%. Yet, hepatitis E is unusual among hepatitis viruses for its severity in pregnant woman, in whom the fatality rate may reach 20%.

[Aside 1: For aficionados, hepatitis A is a picornavirus, hepatitis B is a hepadnavirus (a DNA retrovirus), and hepatitis C is a flavivirus. Hepatitis E-like viruses were originally classified as calciviruses. However, sequencing of their RNA genomes revealed that they are more similar to rubella virus, a togavirus, than to the calciviruses. Yet they are different enough from togaviruses to merit their own family. The prototype is the hepatitis E virus, discovered by Balayan. Like hepatitis A virus, it is spread by the fecal-oral route. Hepatitis E virus is found worldwide, but it is most problematic in developing countries.]

Here then is Balayan’s tale. In 1983 Balayan was investigating an outbreak of non-A, non-B hepatitis in Tashkent; now the capital city of Uzbekistan. Balayan wanted to bring patient samples back to Moscow to study. However, he had no means for refrigerating the samples. Moreover, he may not have had permission from his supervisors to return with the samples. So, he solved his dilemma by a rather extreme form of self sacrifice—he drank a pooled filtrate of patient stool samples. He is said to have made his private inoculum more palatable by first mixing it with yogurt.

Belayan’s efforts were not for naught since, after returning to Moscow, he indeed came down with hepatitis, as he presumably desired. In fact, he became seriously ill. He then began to collect his own stool samples, in which he detected, by electron microscopy, 32 nm virus particles that produced a hepatitis-like illness when inoculated into monkeys. Balayan then observed a virus in the stool of these monkeys that appeared to be identical to the virus in the original patient samples, which he transported in, and recovered from himself.

Hepatitis E Virus
Hepatitis E Virus

Belayan’s virus looked like hepatitis A virus in electron micrographs. But, he could show that it was not hepatitis A virus. He already had antibodies against the hepatitis A virus, and these did not react with the new virus.

Balayan mentions himself in his original report (2), as follows: “Hepatitis E virus (HEV) was first identified in the excreta of an experimentally infected human volunteer and further confirmed by similar findings in clinical specimens from patients with acute jaundice disease different from hepatitis A and B.”

References:

1. The Struggle Against Yellow fever: Featuring Walter Reed and Max Theiler, Posted on the blog May 13, 2014.

2. Balayan, M.S., 1983. Hepatitis E virus infection in Europe: Regional situation regarding laboratory diagnosis and epidemiology. Clinical and Diagnostic Virology 1:1-9.