CDC Combats Rare Disease with Cutting-Edge Science
CDC scientists are keeping a pulse on monkeypox, a rare viral disease that occurs mainly in the rainforests of Central and West Africa, through science that sounds more like fiction than fact. From sophisticated climate data collected by satellites to a glow-in-the-dark virus injected into African rodents, cutting-edge science is helping CDC and its partners plot, predict and intervene in the spread of the zoonotic disease that can jump from animals to humans.
The disease is called “monkeypox” because it was first discovered in laboratory monkeys in 1958. Blood tests of animals in Africa later found that other types of animals probably had monkeypox too, including squirrels, rats, mice and rabbits. Similar to smallpox, though less severe, monkeypox can spread to humans from an animal bite or direct contact with an infected animal’s lesions or body fluids. The disease can also spread from person to person. Up to 10 percent of those who are infected die from the disease.
A recent survey of nine rural Congo health districts concluded that monkeypox was 20 times as common there as it was 30 years ago, when vaccination for smallpox – a related disease – was discontinued.
CDC's virus hunters
“We think that a combination of factors have contributed to the increase in monkeypox cases, particularly in Central and West Africa, including better surveillance and a heightened awareness of the disease, although we’re definitely seeing an increase over time,” said Darin Carroll, Ph.D., a wildlife ecology expert who heads up CDC’s monkeypox program.
In 2003, a monkeypox outbreak in the U.S. (watch the video) resulted after prairie dogs sold by an exotic pet dealer came in contact with a shipment of infected African rodents. Although no one died, imports of African rodents have since been banned.
“The 2003 U.S. outbreak led to tremendous interest in what animals carried the virus, what the transmission was and where could it occur,” said Kevin Karem, Ph.D., poxvirus team leader in CDC’s Poxvirus and Rabies Branch.
Monkeypox lights up in the lab
CDC is leveraging advanced technology to help answer those questions – both in the lab and in the field. A CDC Foundation partnership with the University of Wisconsin-Madison, CDC and the National Wildlife Health Center is helping scientists better understand how the disease affects host animal species and how it is transmitted from animals to humans. Colonies of potential host species are being raised in the Democratic Republic of Congo (DRC) by an in-country partner, and studies of the rodents will soon be underway at CDC and the University of Wisconsin. University of Wisconsin scientist Jorge Osorio, Ph.D., will inject rodents with a "glow-in-the-dark" version of the virus, created using DNA from fireflies, to track the disease in real-time and discover exactly how and when monkeypox spreads.
Surveillance from the sky
The laboratory work funded through the CDC Foundation is one part of a multi-faceted approach to understanding and combating the disease. CDC works with other partners to employ satellite technology to conduct geographic studies of where the disease occurs and how ecology contributes to the spread of disease among animals and humans.
“Satellites are helping us collect data in remote areas of Central Africa that we couldn’t otherwise reach," said Carroll. "What we’re learning about host animal habitats is helping us predict where we should expect to see a human case next – and maybe even when. We want to better understand the risk factors: what it is about those areas that make them conducive to human cases?”
Educating communities and health workers on the ground
People who live near Congolese rainforests often hunt pox-infected rodents for food, which can trigger an outbreak. CDC has collaborated with the International Conservation and Education Fund (INCEF) to produce and distribute videos about the disease. INCEF staff travel through war-torn DRC village by village, to show the videos and help communities and healthcare workers learn how to recognize, prevent and treat monkeypox.
“The work we’re doing with help from the CDC Foundation dovetails nicely into our overall mission, because it will give us the foundation for solid public health interventions,” said Karem. “If we can get information through our research that leads to targeted recommendations to prevent people from getting monkeypox, that’s the end goal.”
Virus Hunters: Interview with MonkeyPox Virus Hunter Anne Rimoin (A Take Part video)
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CDC Public Health Matters Blog | December 22, 2011