Revolutionizing heartworm treatment: Could reducing doxycycline dose transform canine care?

When it comes to treating heartworms in dogs, the American Heartworm Society suggests using doxycycline before giving adulticide treatment. This is to lower the levels of Wolbachia and its byproducts, which can cause lung problems. Past studies have found that giving doxycycline at 10 mg/kg twice a day for 28 days can effectively get rid of Wolbachia. However, what hasn't been determined is how important this removal really is for the dog's health. The guidelines also suggest waiting 30 days after giving doxycycline before using adulticide treatment. This waiting period is meant to clear out byproducts like Wolbachia surface protein and to further reduce heartworms. But, there might be benefits to using less doxycycline and skipping the wait time, which could be better for the pet, the owner, and the vet.

Study details:

To find out more about these treatment methods, scientists put adult Dirofilaria immitis worms into 45 dogs. They split the dogs into nine groups of five. After 75 days, two groups got doxycycline orally at 5, 7.5, or 10 mg/kg twice a day for 28 days. They also got ivermectin once a month at 6 µg/kg. Three groups didn't get any treatment. The scientists checked the dogs before treatment, and then 30 and 60 days after.

Study results:

The average weight of the worms wasn't affected by the dose of doxycycline, but it did go up a lot at 30 days and down a lot at 60 days after treatment, even in the groups that didn't get any treatment. The scores for lung damage didn't show big differences between the groups, except for one group that wasn't treated. The scientists also looked at liver enzymes, which can be a concern with doxycycline. They didn't find any problems with alanine aminotransferase or alkaline phosphatase.

Whether they followed the 30-day wait period recommended by the American Heartworm Society or not, the dogs' lung damage didn't consistently get worse. Also, using less doxycycline didn't make the lung damage worse, and it didn't affect how well the worms were reduced. The average worm weight did go up before the wait period and then down after. In the future, scientists will look into treatment methods that include adulticide treatment (like melarsomine) to see if they can find ways to help pets and owners even more.