Dirofilaria immitis infestation in imported police (K-9) dogs in Iraq:

clinicopathological and molecular investigations study

Abstract

Dirofilaria immitis, the cause of heartworm infestation (HWI) or dirofilariasis, affects members of the Canidae and remains a worldwide clinical problem. In Iraq, dirofilariasis was believed absent until 2009, when the Karbala Governorate was reported as an endemic area for canine dirofilariasis. Consequently, this study intended to investigate the occurrence of Dirofilaria immitis in police dogs in one police academy in Iraq and to study the gross and histopathological changes in 5 dead dogs, as well as to identify the species of the causative parasite using PCR technique. Thirty-nine police dogs, aged between 6 months and 12 years were included in this study. For the microfilariae investigation, 5 ml blood samples were collected from all dogs in EDTA tubes and examined by Knott’s method. The systemic necropsy performed in five dead dogs showed severe clinical signs of dirofilariasis and tissue specimens were sent for routine histopathological processing. For the molecular analysis, adult worms of the detected Dirofilaria spp. were used for DNA extraction and
amplification of the cox1 gene. Fifteen of 39 (38.46%) dogs were diagnosed with moderate to severe microfilariasis. The dead dogs revealed typical severe clinical signs of dirofilariasis. Moreover, typical gross and histopathological changes were also seen, accompanied by generalized thromboembolic lesions, suggesting the occurrence of the caval syndrome. The PCR investigation confirmed that D. immitis was the species present in Iraq. In conclusion, this study establishes that Iraq is a newly reported endemic area for dirofilariasis. Moreover, the infestation occurring in these cases most probably happened inside Iraq. The authors recommend doing further epidemiological studies concerning the occurrence of D. immitis in local dogs as well as in the imported dogs in all Iraqi governorates to better understand the epidemiological map of this disease and to introduce an active treatment and preventive program. Awareness and education regarding this disease should be provided to the veterinarians, dog guiders and people in direct contact with dogs, as this disease is one of the important zoonotic diseases.