Scientists Fear Monkeypox Can Be Passed By Humans

A potentially dangerous virus called monkeypox has broken out among people living in the war-torn areas of Zaire, challenging a long-held scientific assumption that this sister to the human smallpox virus rarely could be transmitted between humans.

An international team of scientific experts sent to investigate the outbreak in February had to be evacuated earlier this month before completing its mission because of intense warfare in the area, officials of the World Health Organization said last week.

Nevertheless, the team confirmed that more than 100 people living near the Zairean town of Lodja had contracted monkeypox.

Public health officials meeting in Geneva last week expressed concern about the international implications of the outbreak in light of the 1977 eradication of smallpox.

Once the biggest public health scourge, smallpox was a contagious human virus that killed more people in the 20th century than all wars combined. But a global vaccination campaign eradicated smallpox, and by 1978 most countries ceased immunizing their children. Thus, few people born after 1978 are immunized against vaccinia-type viruses, which include smallpox and monkeypox.

Twenty years ago WHO felt it was safe to abandon smallpox vaccination even though a genetically similar form of the vaccinia existed in wild African monkeys and could infect people. The reason, WHO’s Dr. David Heymann said Thursday, was that monkeypox rarely spreads from person to person.

The current Zaire outbreak seems to challenge that assumption.

In a speech last week before the Fifth International Conference on Travel Medicine, Heymann - head of WHO’s division on emerging diseases - showed graphic slides of new patients covered in the often disfiguring poxs, their skin blistering from head to toe. And he said the current outbreak had passed through at least nine rounds of human beings - meaning one set of people passed the vaccinia on to another, and so on - at least nine times.