CDC reports 3 human cases caused by new orthopoxvirus
Scientists with the US Centers for Disease Control and Prevention (CDC) have detected a new orthopoxvirus—the family of viruses that includes smallpox and cowpox—in three people in the nation of Georgia, including two herdsmen, the CDC reported in a news release yesterday.
The finding was announced this week at the CDC's 63rd Annual Epidemic Intelligence Service (EIS) Conference, which highlights the work of CDC's EIS officers, or "disease detectives."
When the two herdsmen, neither of whom was vaccinated against smallpox, became ill after contact with sick cattle last summer, the CDC investigators determined through extensive testing that they were infected with a previously unknown orthopoxvirus.
The CDC team then interviewed 55 people who had contact with the herdsmen or with cattle. They found that, of 9 interviewees born after routine smallpox vaccination had stopped in 1980 because of eradication of the disease, 5 had orthopoxvirus antibodies. They also discovered an additional case in a different region of Georgia in a person who was originally suspected of having anthrax in 2010.
The new virus causes painful blisters on the hands and arms, as well as fever, swollen lymph nodes, and weakness, according to a story today from NPR. The patients survived their infections, the CDC said.
The CDC researchers also found evidence that some of the herdsmen's cows had previously been exposed to orthopoxviruses and that viruses also circulated among rodents in the area, the agency said.
The researchers conclude, "Orthopoxviruses are anticipated to emerge in the absence of routine smallpox vaccination and should be considered in persons who experience cutaneous lesions after animal contact."
EIS conference abstract
Apr 30 CDC news release
May 1 NPR story
Experts argue smallpox virus stocks should be kept for now
US and Brazilian experts today make the case for postponing destruction of the last known live strains of variola, the virus that causes smallpox, because crucial scientific questions remain unanswered and important public health goals have not been met, according to their commentary in PLoS Pathogens.
The issue of smallpox virus destruction will be on the agenda when the World Health Assembly, the governing body of the World Health Organization, meets later this month.
The experts, Inger K. Damon, MD, PhD, of the CDC, Clarissa R. Damaso, PhD, of the Universidade Federal do Rio de Janeiro, and Grant McFadden, PhD, of the University of Florida, summarize the research achievements on live variola over the past several decades, including several new smallpox vaccines and two new drug candidates.
"While certain aspects of the original research goals using live virus have been met, other key items, like the wider approval of accurate diagnostics that can distinguish smallpox from other orthopoxvirus diseases or the full licensure of new antiviral drugs and vaccines that are effective against variola virus, have not yet been completed," the experts write.
They say that "greater exploitation of current technologies may lead to additional therapeutic or diagnostic products to better respond to any future emergency situation resulting from a smallpox appearance."
May 1 PLoS Pathog commentary