Under normal circumstances, the damaging effects of heartworms can be treated and cured but veterinarians are now facing an unparalleled challenge. The nation's sole provider of Immiticide, the only heartworm treatment drug approved by the Federal Drug Administration, has run out.
Without the proper post-infection treatment, a simple mosquito bite can turn deadly if heartworm prevention is not practiced. Kellie Littrell, DVM, assistant veterinarian with the Cartersville-Bartow Veterinarian Group, expounded on the situation as seen by veterinarians.
"Without an available treatment, there's a lot of uncertainty. We as veterinarians, just want to get the word out to pet owners to make them aware of the situation so they know how important it is going to be to keep their dogs on preventatives because we feel helpless," Littrell said. "Preventatives are more important than ever."
Immiticide, an adulticide product for the treatment of heartworms, is produced by Merial. Earlier this month, Merial sent a letter to veterinarians warning of an impending shortage asking their customers to limit its use only to extreme cases. Upon this news, Merial experienced a rush of orders for restocking and ran out of the medication earlier than expected.
"Even our hospitals, for the amount we were able to restock, we just barely have enough to treat dogs we currently know are infected. So, any future infection we find, we'll just have to manage," Littrell said. "There is no treatment available now for heartworm infections and the current recommendation is going to be just to manage those cases until that treatment becomes available again and they haven't given any indication as to how long that will be. So, we don't know if that will be months, weeks, years. We have no idea."
Both dogs and cats are susceptible to heartworms and if left untreated, the infection can be fatal. The American Heartworm Society lists three primary goals for veterinarians to follow given current circumstances when presented an animal with heartworms.
* Reduce potential pathology from the infection.
* Maintain the health of the dog until it can be appropriately treated.
* Prevent additional heartworm infection of the dog.
To reduce pathology, all activity is restricted as the infection persists. This includes strict confinement of the animal for up to many months at a time.
"The severity of heartworm disease is directly related to the activity level of the dog," the AHS said. "As physical activity increases, pathology associated with adult heartworms increases."
A regiment of various medication is then used to prevent additional infection. Littrell explained the re-infection cycle and dangers of heartworms as they incubate and reproduce.
"If an adult heartworm is living in a dog's heart, it can give off babies who can re-infect for future periods and re-infect that same dog as well as infect a mosquito that may come along and then transmit to other pets," Littrell said. "The fact of the matter is, without getting rid of those adult heartworms, they are going to cause damage and it's just a matter of how bad it's going to be. So, it's not good at all."
Merial cites production problems for delaying manufacture of the drug with no clear timeline as to when manufacturing will resume. David Kirkpatrick, media relations manager with the American Veterinarian Medical Association, emphasized prevention, as did Littrell, and advises pet owners to take all precautions if sickness appears.
"The important thing here is for pet owners to maintain any heartworm regiment they are on," Kirkpatrick said. "As soon as they see any signs or indications of sickness, they should contact their vet as soon as possible."