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| |  First World War Disease Has Come Back To Threaten Homeless AIDS Patients SAN FRANCISCO, CA -- December 29, 1997 -- A bacterial infection that afflicted tens of thousands of soldiers in the trenches during the first World War is making a comeback of sorts, threatening the lives of homeless AIDS patients. The discovery was made by a research team led by Jane Koehler, MD, a microbiologist and an assistant professor of medicine at the University of California-San Francisco, who set out to identify the microbes responsible for a chronic, relapsing infection called bacillary angiomatosis. Although it is curable with common antibiotics, the illness, in addition to making its victims sick and feverish, often goes undiagnosed, Koehler said. In AIDS patients, who have weakened immune systems, infection with the disease-causing microbes causes skin lesions that are easily mistaken for Kaposi's sarcoma, another disease that often strikes people with AIDS. In immune-compromised individuals, bacillary angiomatosis can lead to serious complications, including anemia, weight loss, the growth of non-malignant tumours that can hinder breathing or other vital functions, damage to the valves that guide blood flow through the heart and death. In a study published in the Dec. 25, 1997 issue of the New England Journal of Medicine , Koehler and colleagues surveyed 49 bacillary angiomatosis patients and determined which bacterial species were associated with the illness. Koehler's research team found that, depending on socio-economic characteristics, AIDS patients diagnosed with bacillary angiomatosis were infected with two distinct species of bacteria. A species called Bartonella quintana, first identified by Koehler as a bacillary-angiomatosis-causing microbe in 1992, was the source of infection in 23 patients in the study, most of whom were poor, homeless and exposed to body lice. B. quintana is the cause of trench fever, which sickened troops confined to trenches in Europe during the first World War. At that time trench fever was found to be associated with body lice infestation. B. quintana bacteria live within lice and are transmitted from human to human by the louse. Trench fever was not discovered in the United States until 1992, when 10 cases were identified among the homeless population in Seattle, Koehler said. Thus far, no clear genetic distinctions between B. quintana strains that have sickened the immune-competent and strains that have afflicted AIDS patients have been identified, according to Koehler. While infection with B. quintana does not appear to be widespread, the real incidence of infection is underestimated, Koehler suggests. "The homeless are an incredibly neglected population in terms of medical care," Koehler added. "To a large extent this disease may go undiagnosed among the homeless and when it gets into AIDS patients who are homeless it can actually kill them." A related bacterium, Bartonella henselae, was first identified a few years ago as a cause of bacillary angiomatosis in AIDS patients and as the cause of 22,000 cases of cat scratch fever each year. In a previous study Koehler determined that B. henselae appears to be transmitted to AIDS patients from their cats. Koehler and colleagues found that 41 percent of the cats tested in San Francisco had B. henselae in their bloodstreams and that fleas easily transmit this bacterium from cat to cat. Koehler advises AIDS patients to wash after exposure to cats and to control fleas as much as possible, but she said the threat of infection does not warrant getting rid of beloved pets. In the current study, Koehler's research team found that 26 of the HIV-positive bacillary angiomatosis patients were infected with B. henselae. Infection with this bacterial species was strongly associated with exposure to cats and cat fleas, but not to poverty, homelessness or exposure to lice. The two disease agents cause many similar symptoms, but in the current study only B. henselae was associated with a condition in which blood-filled cysts arise within the liver and decrease liver function. Only B. quintana was associated with bone growths. The name bacillary angiomatosis refers to the unexplained ability of the bacteria to stimulate the formation of blood vessels that feed these growing lesions. The good news for the HIV-infected who have access to health care is that common antibiotics, called macrolides -- which already are prescribed for the HIV-infected to prevent and treat another opportunistic bacterial infection, called Mycobacterium avium complex -- can apparently simultaneously prevent and treat bacillary angiomatosis that arises from infection with either Bartonella species, Koehler said.
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