Marburg hemorrhagic fever associated with multiple genetic lineages of virus.

BACKGROUND: An outbreak of Marburg hemorrhagic fever was first observed in a gold-mining village in northeastern Democratic Republic of the Congo in October 1998. METHODS: We investigated the outbreak of Marburg hemorrhagic fever most intensively in May and October 1999. Sporadic cases and short chains of human-to-human transmission continued to occur until September 2000. Suspected cases were identified on the basis of a case definition; cases were confirmed by the detection of virus antigen and nucleic acid in blood, cell culture, antibody responses, and immunohistochemical analysis. RESULTS: A total of 154 cases (48 laboratory-confirmed and 106 suspected) were identified (case fatality rate, 83 percent); 52 percent of cases were in young male miners. Only 27 percent of these men reported having had contact with other affected persons, whereas 67 percent of patients who were not miners reported such contact (P<0.001). Most of the affected miners (94 percent) worked in an underground mine. Cessation of the outbreak coincided with flooding of the mine. Epidemiologic evidence of multiple introductions of infection into the population was substantiated by the detection of at least nine genetically distinct lineages of virus in circulation during the outbreak. CONCLUSIONS: Marburg hemorrhagic fever can have a very high case fatality rate. Since multiple genetic variants of virus were identified, ongoing introduction of virus into the population helped perpetuate this outbreak. The findings imply that reservoir hosts of Marburg virus inhabit caves, mines, or similar habitats.

Use of protective gear and the occurrence of occupational Marburg hemorrhagic fever in health workers from Watsa health zone, Democratic Republic of the Congo.

BACKGROUND: Occupational transmission to health workers (HWs) has been a typical feature of Marburg hemorrhagic fever (MHF) outbreaks. The goal of this study was to identify cases of occupational MHF in HWs from Durba and Watsa, Democratic Republic of the Congo; to assess levels of exposure and protection; and to explore reasons for inconsistent use of protective gear. METHODS: A serosurvey of 48 HWs who cared for patients with MHF was performed. In addition, HWs were given a questionnaire on types of exposure, use of protective gear, and symptoms after contact. Informal and in-depth interviews with HWs were also performed. RESULTS: We found 1 HW who was seropositive for MHF, in addition to 5 cases of occupational MHF known beforehand; 4 infections had occurred after the introduction of infection control. HWs protected themselves better during invasive procedures (injections, venipuncture, and surgery) than during noninvasive procedures, but the overall level of protection in the hospital remained insufficient, particularly outside of isolation wards. The reasons for inconsistent use of protective gear included insufficient availability of the gear, adherence to traditional explanatory models of the origin of disease, and peer bonding with sick colleagues. CONCLUSIONS: Infection control must not focus too exclusively on the establishment of isolation wards but should aim at improving overall hospital hygiene. Training of HWs should allow them to voice and discuss their doubts and prepare them for the peculiarities of caring for ill colleagues.

Studies of reservoir hosts for Marburg virus.

To determine reservoir hosts for Marburg virus (MARV), we examined the fauna of a mine in northeastern Democratic Republic of the Congo. The mine was associated with a protracted outbreak of Marburg hemorrhagic fever during 1998-2000. We found MARV nucleic acid in 12 bats, comprising 3.0%-3.6% of 2 species of insectivorous bat and 1 species of fruit bat. We found antibody to the virus in the serum of 9.7% of 1 of the insectivorous species and in 20.5% of the fruit bat species, but attempts to isolate virus were unsuccessful.

Risk factors for Marburg hemorrhagic fever, Democratic Republic of the Congo.

We conducted two antibody surveys to assess risk factors for Marburg hemorrhagic fever in an area of confirmed Marburg virus transmission in the Democratic Republic of the Congo. Questionnaires were administered and serum samples tested for Marburg-specific antibodies by enzyme-linked immunosorbent assay. Fifteen (2%) of 912 participants in a general village cross-sectional antibody survey were positive for Marburg immunoglobulin G antibody. Thirteen (87%) of these 15 were men who worked in the local gold mines. Working as a miner (odds ratio [OR] 13.9, 95% confidence interval [CI] 3.1 to 62.1) and receiving injections (OR 7.4, 95% CI 1.6 to 33.2) were associated with a positive antibody result. All 103 participants in a targeted antibody survey of healthcare workers were antibody negative. Primary transmission of Marburg virus to humans likely occurred via exposure to a still unidentified reservoir in the local mines. Secondary transmission appears to be less common with Marburg virus than with Ebola virus, the other known filovirus.