Incidence of Dirofilaria immitis in dogs presented at University of Nigeria, Nsukka Veterinary Teaching Hospital using wet smear and buffy coat techniques

Differential diagnosis of Dirofilaria immitis nematodes (Nematoda, Onchocercidae)

Heartworm disease is a widespread anthropozoonotic disease of carnivorous animals, as well as humans. It is caused by nematodes belonging to the suborder Filariata, family Onchocercidae, genus Dirofilaria. There are about 26 species of heartworms in nature, the most common and pathogenic species in dogs and cats in most countries is Dirofilaria immitis Leidy, 1856. Mature helminths parasitize in the right ventricle and pulmonary arteries, large veins of animals and cause heart and vascular disorders, and death. Therefore, the aim of the study was to investigate the features of morphological and metric structure of adult nematodes of D. immitis isolated from the heart of dogs. Morphological studies have shown that in males the most characteristic differential features are the presence of two unequal spicules, specifically positioned relative to each other, as well as well-defined preanal and less pronounced adanal and postanal papillae. In female heartworms, the characteristic morphological features are the shape and location of the vulva. There is a difference in the structure of the esophagus in males and females. In females, the anterior and posterior parts of the esophagus are well expressed, with enlargements, in males these divisions are not pronounced. To increase the efficiency of species identification of D. immitis nematodes, it is proposed to use metric parameters that characterize the overall body size, body and width of esophagus in different areas, length of esophagus, and the location of the nerve ring. In males, 11 indicators are also suggested that characterize the size of the spicules and the location of the cloaca. In females, seven additional parameters are pointed out that characterize the location of the vulva, anus and body width in these areas. The obtained data expand the already existing data on the peculiarities of the morphological structure of parasitic nematodes of the species D. immitis and their identification.

Canine Dirofilariasis: A Case Report and Review of the Literature

Dirofilariasis is a disease of clinical importance in dogs. It is to this end that a case of a seven-year-old mongrel with dirofilariasis was presented to examine the unique features and presentation in the canine patient in question. The dog had clinical signs consistent with the disease. Further diagnostic tests were performed to establish the presence and severity of the disease and make an appropriate treatment plan. The Knott’s test revealed Dirofilaria species in the circulating blood and radiography showed right ventricular hypertrophy with pulmonary arterial enlargement and increased bronchial opacification. The treatment instituted was ivermectin therapy by subcutaneous injection every two weeks for six months, cardiac glycoside and antibiotics for 14 days. The clinical signs resolved after completion of the treatment. A general overview of heartworm infection in dogs was also done to update current knowledge of the disease. Though the risk of significant propagation of Dirofilaria immitis is considered low, with the climate change and international pet travel regulations, this emerging zoonosis remains a threat.

The global status of Dirofilaria immitis in dogs: a systematic review and meta-analysis based on published articles

Dirofilaria immitis is a parasitic filarial nematode responsible for heartworm disease in domestic as well as wild canines and felines and pulmonary or cutaneous infections in humans. This systematic review and meta-analysis aimed to evaluate the status of D. immitis in dogs based on available literature. Four English language databases (ISI Web of Science, Scopus, PubMed and Science Direct) containing data on D. immitis prevalence in dogs were thoroughly searched resulting in the inclusion of 193 studies. The findings revealed that the pooled and weighted prevalence of D. immitis infection in dog population based on published papers throughout the world was 10.91% (95% CI=10.18-11.65). In addition, subgroup analysis based on meta-regression revealed that a significant difference between the pooled and weighted prevalence of D. immitis in dogs and country (β =0.14, P=0.049). Given the relatively high prevalence of D. immitis infection in dogs and its adverse effects, it is suggested that to perform more research on the prevention and control of dirofilariasis infection in dogs worldwide.