October 9, 2003

City and county health officials are following up on the detection by air sensors of low levels of parts of the bacterium that causes tularemia, a treatable illness occasionally found in humans but more common in rabbits and rodents.

Health officials said that though the bacteria is found naturally in the environment, they are taking precautionary measures to determine if there have been any human cases of tularemia, commonly known as rabbit fever, in the area. So far none have been found.

Low levels of the organism were detected by laboratory tests done on filters taken from special air monitors on Saturday, Sunday and Monday. However, filters tested from Tuesday and Wednesday were negative.

"The new technology in use throughout Houston and Harris County gives us information that was not previously knowable. We are investigating to determine if the bacteria was always present or newly present and if it represents a health threat to the community," said M. desVignes-Kendrick, MD, MPH, Director of the Houston Department of Health and Human Services.

Precautionary measures being taken by the City of Houston's Health and Human Services Department and Harris County Public Health and Environmental Services include increased surveillance for human illness, additional environmental sampling, collection and testing of wild rabbits and rodents and an assessment of activities in the area that may have caused the sensors to pick up the organism.

Officials are concentrating on an area of Houston and Harris County from Greens Bayou on the east, the Houston Ship Channel on the south and the Hardy Toll Road on the west.

"The Harris County and Houston health departments are pooling resources and expertise to investigate the potential impact of the findings. We greatly appreciate the ongoing collaboration and support we receive from our partners in the local medical community and local, state and federal agencies," says Herminia Palacio, MD, MPH, Executive Director of Harris County Public Health and Environmental Services.

The air sensors are part of a nationwide BioWatch system inaugurated in March to monitor for intentionally released bacterial agents but may detect naturally occurring organisms.

Health officials say there is nothing to indicate an intentional release of the organism but that the investigation is continuing to see if a naturally occurring explanation for the sensor detection can be identified.

Several federal, state and local agencies are participating.