Newly identified human bocavirus may be associated with pneumonia

The newly identified human bocavirus was found in nearly 5 percent of pneumonia patients in rural Thailand, mostly in very young children. Researchers from the Centers for Disease Control and Prevention report their finding at the International Conference on Emerging Infectious Diseases.

"Our preliminary data suggests that human bocavirus may be associated with pneumonia in Thailand, especially among young children," says Alicia Fry, one of the researchers on the study.

Human bocavirus (HBoV) is a recently identified parvovirus that has been found in respiratory secretions of children with lower respiratory tract infections (LRTI).

First reported in Sweden in September 2005, it is only the second member of the family Parvoviridae to be associated with human disease and the first to be linked with respiratory illness. Two additional studies in Australia and Japan have also identified HBoV in children with LRTI. However, whether the virus causes LRTI, the spectrum of clinical illness, and the epidemiology of HBoV infections still need to be defined. Fry cautions, "We still do not know if the virus actually causes respiratory tract infections and we hope to get closer to the answer with our final analysis."

The research was carried out through the Thailand International Emerging Infection Program (IEIP), a collaborative project between the Thailand Ministry of Health and the CDC that began in 2001. "The Thailand IEIP population-based surveillance for severe pneumonia patients of all ages is a unique opportunity to define the epidemiology of new viruses, "says Sonja Olsen, Acting Director of the IEIP and one of the researchers.

The researchers tested nasopharyngeal swab specimens collected from hospitalized pneumonia patients in rural Thailand between September 1, 2004 and August 31, 2005 for the presence of HBoV and compared them with specimens taken from a group of healthy volunteers. In preliminary analysis, 53 (4.5%) of 1178 hospitalized patients with pneumonia were positive for HBoV compared to 3 (1%) of the 281 samples in the healthy control group. Among the hospitalized patients, over half (51%) of the HBoV infections were found in children less than one year of age and 30% were in children 2-5 years of age.

Future studies need to be done to determine the epidemiology of HBoV in the United States and elsewhere around the world.

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