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Research in the "Hot Zone"

May 3, 2004

Heather Heilman
Phone: (504) 865-5714

hheilman@tulane.edu

When Dan Bausch was in medical school, he didn't imagine that his career would lead to trapping bats in caves in the Democratic Republic of Congo.

hotzoneBausch is an expert on viral hemorrhagic fevers, illnesses that cause fever and damage to the coagulation system and often the heart, leading to bleeding and shock.

Four genetically distinct viruses cause these diseases, which include yellow fever, dengue fever, Lassa fever, hantavirus pulmonary syndrome and Ebola hemorrhagic fever.

"Contrary to what you read in The Hot Zone, Ebola doesn't make your eyeballs melt," he said. "Many people don't show external bleeding with these diseases, though they can have very severe internal bleeding and go into shock."

Bausch is mainly focused on diseases that occur in sub-Saharan Africa. Until last year, he was a medical officer in the special pathogens branch of the epidemiology unit of the Centers for Disease Control and Prevention.

He directed a field station in Guinea and responded to outbreaks of viral hemorrhagic fevers, including hantavirus in Bolivia, Ebola in Gabon and Uganda, Lassa fever in Guinea and Sierra Leone, and Marburg in Congo. He was in the caves of Congo looking for the reservoir of the Marburg virus. Marburg is a relative of the Ebola virus that, like Ebola, kills between 80 and 90 percent of those it infects.

Also like Ebola, the animal that serves as the "natural habitat" of the virus is unknown. But after an outbreak of Marburg among Congolese gold miners, Bausch speculates that bats could be the reservoir. Ebola and Marburg are emerging diseases in the sense that they have only fairly recently been identified and much is still unknown about them.

Scientists first identified Marburg virus in 1967 and Ebola in 1976 but they probably were infecting humans long before then. There may have been isolated outbreaks in rural areas that devastated families and small villages but never spread beyond that.

"In recent decades we've seen larger outbreaks, in part because of halfway measures of hospital development in sub-Saharan Africa," Bausch said. "Hospitals have been built, but the staff may not be well-trained, and they might not be adequately supplied with gloves and masks and needles. So someone comes in with Ebola and they infect a couple of healthcare workers and a couple of patients, and it accelerates."

Since last summer, Bausch has been an associate professor of tropical medicine at Tulane. He isn't new to the university--he received a master's degree in public health from Tulane and was an adjunct professor of tropical medicine while at the Centers for Disease Control. He is now focused on the Lassa virus in West Africa.

Lassa is dangerous and highly contagious, although not as lethal as Ebola. There is a therapy for the disease, though its effectiveness is limited. The reservoir of the virus is known to be a rodent called mastomys. Like most viral hemorrhagic fevers, however, Lassa can be difficult to diagnose because the symptoms are similar to many other diseases.

"People may die in sub-Saharan Africa of what looks like severe malaria, but may actually be Lassa," he said.

In order to make the diagnosis, doctors have to find the virus or antibodies to the virus. In Guinea, Bausch is working on a method to diagnose Lassa by detecting the antibody in blood. But since he's been at Tulane, he's spent as much time working on HIV protocols as Lassa. Viral hemorrhagic fevers, particularly Ebola, attract attention because they're exotic and spectacularly deadly.

However, they also are relatively rare on a continent that perennially struggles with malaria and tuberculosis and is being devastated by HIV and AIDS.

"We need to make sure that our research overseas is applicable to the concerns of the population," he said. "The work that we did at the CDC was fairly dramatic. There's an outbreak and you stop it. That's good, but I think in order to make progress, you need a longer-term investment."

Bausch believes that scientists should work within the context of human rights. He thinks that when Western public health workers go to Africa to fight an outbreak of diseases like Ebola, they also should be concerned with leaving behind a public health infrastructure that would help Africans deal with future outbreaks of all kinds. But he doesn't want to downplay the risk of viral hemorrhagic fevers.

Ebola and Marburg are rare diseases, but they have fatality rates of between 80 and 90 percent, so there is concern that they could be used as agents of bioterrorism. "Ultimately, understanding more about these viruses will be to the benefit of industrialized and developing countries, alike."

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