Atlanta — Numbers of rabies cases have more than doubled this year compared to the first six months of 2007, prompting the Georgia Division of Public Health to undergo an investigation into what state officials deem an “outbreak.”

The news comes as the Centers for Disease Control and Prevention reveals the supply of human rabies vaccine is low, prompting the agency to put parameters on its distribution until supply levels are restored next month. To conserve limited resources, distribution of vaccine for pre-exposure prophylaxis now requires approval by state and federal authorities. Priority will be given to those with occupational rabies exposure risk, such as veterinary staff, animal-control officers and wildlife workers.

While most of Georgia’s rabies cases involve wildlife, 215 animals tested positive this year compared to 134 during the same time last year, says Dr. Dana Cole, of the Georgia Division of Public Health. In some regions, reported cases have more than tripled, she adds.

State officials are trying to determine whether growing awareness and diagnosis of rabies or urban sprawl into wildlife areas have played a role in the outbreak. Records show 1,445 animals were tested this year, compared to 1,199 during the first six months of last year.

Cole says she’s working with authorities in Tennessee and North Carolina to monitor rabies in raccoons along state borders.