Released today, the 2010 heartworm incidence survey conducted by the American Heartworm Society (AHS) reveals that despite weather conditions considered unfavorable to mosquito proliferation, heartworm disease was diagnosed in every state in the U.S. and almost every county and parish.
This survey focused on 2010 heartworm diagnoses, representing data from more than 5,000 veterinary clinics across the country reporting clinic testing and heartworm-positive dogs and cats.
“The pattern of heartworm incidence overall was similar to that of previous years,” says Wallace Graham, DVM, AHS president.
“We believe that because the summer of 2009 was cooler in some areas of the country and drier in others, mosquitoes and heartworms 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 positive reports.
By contrast, Graham explained, the 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.
“The key point to remember is that none of us can predict the weather and know in advance whether the conditions will be ripe for heartworm transmission,” Graham says.
“Additional factors play roles in transmission, including wildlife that serve as reservoirs for infection and a likely decrease in the number of protected dogs, due to documented decreases in purchases of heartworm preventives.
“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 AHS Heartworm Incidence Survey has been conducted every three years since 2001 for the purpose of tracking trends in heartworm incidence and informing the public about the need for year-round heartworm prevention.
For more information on heartworm disease and the AHS Heartworm Incidence Survey, click here.