veterinarianon here: In addition to HCQ- ivermectin has also found to be promising/effective against covid19 , and both treatments are filaricidal - the azithromycin may be effective against a commensal organism (like killing wohlbachia spp. to weaken heartworms in a dog)
The common denominator
could be another filarial
disease- like heartworm disease -as well .
Synapses firing here….
mosquitoes/other biting/blood sucking insects may be vectors