Based on latest findings, the American Heartworm Society (AHS) has updated their guidelines, particularly in terms of heartworm prevention and testing.
Further emphasis is placed on year-round administration of heartworm preventives, particularly due to documented presence of resistant subpopulations of heartworms.
The AHS recommends antigen plus microfilaria testing.
Antigen testing is considered the most sensitive diagnostic method for screening asymptomatic dogs or to confirm a suspected heartworm infection. Because of potential false negatives, AHS recommends microfilaria testing together with antigen testing.
The AHS recommends doxycycline and macrocyclic lactone administration prior to adulticide therapy in treatment of infected dogs.
The recommended heartworm treatment protocol for dogs includes administration of a macrocyclic lactone preventive coupled with doxycycline to suppress embryogenesis of heartworms, weaken adult heartworms and decrease post-treatment complication rates.
The reason for the doxycycline administration in heartworm treatment is quite fascinating.
New research has shown that many complications that occur as a result of heartworm disease itself, or its treatment, are due to Wolbachia, agram-negative intracellular bacterium. Wolbachia infects all life stages of the heartworm and the two seem to have a symbiotic relationship. This bacterium is believed to be necessary for the development, reproduction, and long-term survival of the parasite.
A direct relationship has been shown between the inflammation associated with heartworm disease and the presend of the bacterium within the microfilaria.
Read more about this here.
American Heartworm Society issues revised guidelines
Current Canine/Feline Guidelines
American Heartworm Society Resistance Statement
Wolbachia and Their Role in Heartworm Disease and Treatment
Don't Let Heartworm Become A Heartbreak!
Veterinarians Answer: Heartworm Disease And Prevention
Reading About Heartworm Is One Thing; Watching A Dog Suffer Is Another