Best Practices for Lungworm Prevention & Treatment

Aelurostrongylus abstrusus, the most common lung parasite in cats, is found throughout the world. Infections may be asymptomatic, subclinical, or clinical. Most common signs include coughing, weight loss, tachypnea, and dyspnea. Severe cases may present with open-mouth breathing from interstitial pneumonia, coughing, nasal discharge, and sneezing. Forty-two cats from a private sanctuary were moved to a purpose-built shelter for 65 days. Most cats were in poor body condition and many had signs that could be attributable to lungworms. Fecal examinations were performed on all cats: 10, positive by Baermann method for A abstrusus larvae, were treated with selamectin spot-on at 45 mg on days 4 and 28. Serial fecal examinations showed a rapid decrease in lungworm larvae, and, by day 65, 9/10 cats were successfully treated. All 10 cats were in good body condition with no respiratory signs by study’s close.

CommentaryA abstrusus is spread by ingesting common transport hosts (eg, rodents, birds, amphibians). Although signs may be absent, some cats develop chronic cough and respiratory distress. Many topically applied drugs have been effective (eg, imidacloprid with moxidectin [Advantage Multi], emodepside with praziquantel [Profender]). This study found that selamectin (Revolution) is also effective. Topical medications are preferred for treating lungworm cases, and monthly applications of a broad-spectrum parasiticide as recommended by the American Heartworm Society has the added benefit of controlling other internal and external parasites (eg, fleas, ear mites) with which indoor and outdoor cats have frequent encounters.—Sandra Sawchuk, DVM, MS

SourceEvaluation of the efficacy of selamectin spot-on in cats infested with Aelurostrongylus abstrusus (Strongylida, Filariodidae) in a Central Italy cat shelter. Iannino F, Iannetti L, Paganico D, Podaliri Vulpiani M. Vet Parasitol 197:258-262, 2013.