Blood bronchial mucus with Dirofilaria immitis adult worms after the treatment with doxycycline and moxidectin: a rare case presentation

Abstract Heartworm disease is a serious acquired parasitic infection caused by Dirofilaria immitis that can cause severe lung manifestation, heart failure, and other organ damage in dogs. We hereby present a case of a seven-year-old, intact male which was submitted to treatment of heartworm disease with doxycycline and a single dose of injectable moxidectin. Three weeks later the dog presented an acute coughing, hemoptysis and marked dyspnea and was admitted to the Hospital Veterinário Popular de Mossoró, a private veterinary hospital located in Mossoró, Rio Grande do Norte, Brazil. Some hours after the admission, the dog showed a severe coughing episodes with progressive expectoration and subsequently profuse bloody discharge. At this time, two live worms were coughed out. The nematodes specimens (1 male and 1 female) were collected from bronchial mucus, and morphologically and molecularly identified as D. immitis . A fragment of 635 bp of the cytochrome oxidase C subunit 1 gene was sequenced and deposited at the GenBank database (Accession number: PV729978). The treatment of heartworm disease can be complex, and the veterinarian must evaluate each case individually to determine the best treatment protocol. Veterinarian practitioners must be aware about the risk of this presentation and intervene properly to keep dogs’ welfare.