Fruit bats the culprit in spreading Marburg virus

Aug 22 2007

Scientists have found that fruit bats that roost in caves could be the culprits in the spread of the deadly Marburg virus.

The Marburg virus causes a deadly hemorrhagic fever and is a cousin of the equally deadly but possibly more infamous, Ebola virus.

The researchers discovered the virus in only one common species of fruit bats after testing 1,100 bats of various species; this is the first time it has been detected in an animal other than a monkey.

But the research team which discovered the presence of the virus at the U.S. Centers for Disease Control and Prevention, at the Medical Research Institute in Franceville, Gabon, say Marburg may be more common than previously thought.

For the study bats were collected in the West Africa countries of Gabon and the Republic of Congo; test results support the theory that bats caused two recent Marburg cases in nearby Uganda, say the researchers.

This is the first report of the presence of the Marburg virus in that particular area of Africa and extends the known range of the virus.

The researchers say the data implies that more areas are at risk for Marburg hemorrhagic fever outbreaks than previously thought and supports other studies which report three species of fruit bats are likely reservoirs for the Ebola virus.

The study suggests that controlling these bats could help reduce the threat.

The team of investigators from the CDC, the World Health Organization (WHO) and other health agencies have been in a remote part of western Uganda, following the death last month of a 29-year-old man who worked in a lead mine there.

Last week the WHO reported that Uganda had successfully contained an outbreak of Marburg fever among gold miners after two men became infected and one died.

As with Ebola, the Marburg virus kills before it can spread far, and while bats have been suspected as the source, until now it has not been proven.

The CDC team has been testing bats across several regions of Africa and they found a common species of fruit bat, Rousettus aegyptiacus, was the only one infected with the virus.

The CDC says the Marburg virus-positive bats represent the first naturally infected non-primate animals identified to date.

The CDC says the investigators in Uganda noticed that the ceiling of the cave's tallest chamber was just 10 feet high, and miners' hands and feet were in constant contact with bat guano; at least two kinds of bats have been found in the cave, including the one with the virus.

Since Marburg was first identified in 1967, large outbreaks have been reported in Congo, Angola and other countries.

As it can spread from person to person, international health responses to any outbreaks are a normal procedure.

Test results on the Ugandan bats are expected to take a couple of months.

Between 1998 and 2000, a major outbreak of Marburg occurred among gold miners in the Democratic Republic of Congo resulting in 154 people becoming infected and 128 deaths.

Another outbreak in Uige, Angola, in 2004-05 killed 150 people in 163 reported cases.

The Ebola virus has also infected gorillas; currently there is no vaccine or specific treatment for either disease.

Both diseases cause a severe headache and fever followed by rapid debilitation and bleeding from the eyes, ears and elsewhere; death often follows eight or nine days later.

The study is published in the Public Library of Science journal PLoS ONE.