Heartworm disease diagnosed in every U.S. state, veterinary survey reports
Conducted every three years since 2001, the American Heartworm Society's (AHS) Heartworm Incidence Survey was created to track trends in heartworm incidence. The data was gathered from more than 5,000 veterinary hospitals across the country reporting clinic testing and heartworm-positive dogs and cats.
Weather patterns, says AHS president and veterinarian Wallace Graham, is believed to be influencing mosquito populations. “The pattern of heartworm incidence overall was similar to that of previous years,” he says. “We believe that because the summer of 2009 was cooler in some areas of the country and drier in others, mosquitoes — and heartworm — were somewhat more concentrated in areas with nearby standing bodies of water.”
Study supervisors noted that survey clinics reporting low numbers of heartworm-positive animals often sat side-by-side with clinics with high numbers, AHS reports in a prepared statement.
By contrast, Graham says, the previous 2007 study reflected the homogenizing effects severe weather can have on mosquito populations. In 2007, the fallout from Hurricanes Katrina and Rita had far-reaching effects on mosquito vectors and heartworm transmission.
“AHS recommends that veterinarians be vigilant about recommending annual heartworm testing and year-round use of heartworm protection. Without such vigilance, heartworm incidence numbers could climb higher than ever before,” the association says.