Capuchin Monkey Hepatitis B Virus

Again, scientists identified a novel Hepatitis B virus, although the term 'novel' is used rather losely here. It is novel voor science, but not for nature. This time they discovered a Hepaitits B Virus in Brazilian capuchin monkeys (Cebus spp.) and called it Capuchin Monkey Hepatitis B Virus [CMHBV][1].

Researchers found antibodies that were specific of Capuchin Monkey Hepatitis B Virus in five animals and high concentrations Capuchin Monkey Hepatitis B Virus in one animal. A non-inflammatory, probably chronic infection was seen in all animals.

Further testing revealed that Capuchin Monkey Hepatitis B Virus is related to Woolly Monkey Hepatitis B Virus, which in turn was already known to be closely related to (Human) Hepatitis B Virus (hHBV). Infection-determining Capuchin Monkey Hepatitis B Virus surface peptides bound to the human Hepatitis B Virus receptor (human sodium taurocholate co-transporting polypeptide), but preferentially interacted with the capuchin monkey receptor homologue.

The researchers established that neither Capuchin Monkey Hepatitis B Virus nor Woolly Monkey Hepatitis B Virus was the likely ancestor of the divergent human Hepatitis B Virus genotypes F/H found in American natives.

All known hepatitis B virus genotypes occur in humans and hominoid Old World non-human primates (NHPs). The divergent Woolly Monkey Hepatitis B Virus forms another orthohepadnavirus species. The evolutionary origins of human Hepatitis B Virus are unclear. They speculate that there are two possible routes. One via the migration of Paleolithic hunter-gatherers during the last ice age when the Bering Strait between Asia and the Americas was frozen (between circa 24,000 and 17,000 BC). The other via the so-called Polynesian expansion, where seafarers travelled the Pacific Ocean and likely reached the american continent (between circa 700 and 1756 AD).

[1] Breno Frederico de Carvalho Dominguez Souza et al: A novel hepatitis B virus species discovered in capuchin monkeys sheds new light on the evolution of primate hepadnaviruses in Journal of Hepatology – 2018. See here.