Prevalence and factors associated with Dirofilaria immitis infection in dogs in Sertão Paraibano, Northeast Brazil

Abstract

Dirofilaria immitis is a heart and large vessel parasite that mainly affects domestic dogs and has shown a re-emerging zoonosis in recent years. The objective of this study was to determine the prevalence, associated factors, and geographic areas of D. immitis in dogs in the city of Sousa, Paraíba, Northeast Brazil. A total of 320 dogs were selected and evaluated, 160 domiciled and 160 wandering, from the 32 districts of the city. Clinical examination, blood collection, and epidemiological data retrieval were performed for each animal. The sanitation conditions of the environment were visually observed at the time of evaluation. Three methods were used to investigate the morphometric diagnosis of microfilariae: capillary blood smear (ESC), peripheral blood smear (ESP), and modified Knott test. The data were subjected to univariate and multivariate statistics for the observation of risk factors and qualitative assessment of the examinations. Of the 17.5% (56/320) of animals testing positive for D. immitis, 25% (40/160) were wandering and 10% (16/160) were domiciled dogs. Positive dogs were found in 24 of the 32 neighborhoods evaluated, with Angelim and Doutor Zezé having the highest percentages of 1.56% (5/320) each. Only the categories of cardiac alterations (OR 6.231 [1,539-25,236]) and stray dogs (OR 2.463 [1,281-4,735]) demonstrated potential risk factors for infection. Of the 56 positive animals, 28 were positive in the three tests, and another 28 showed variance between methods and/or between prepared slides. No other filaridae were observed. The city of Sousa is considered to have a significant prevalence of infection by D. immitis, and forms of control and prophylaxis are required to reduce the risks of transmission to animals, as well as to humans.

Epidemiological analysis of Dirofilaria immitis (Spirurida: Onchocercidae) infecting pet dogs (Canis lupus familiaris, Linnaeus, 1758) in Baixada Fluminense, Rio de Janeiro

“…Most of the D. immitis infections documented in Brazil are in coastal areas ( 7 , 29 , 30 ), although infections are not restricted to these environments ( 31 ). The geographical dispersion of the parasite D. immitis in Brazilian previously indene regions are scarce ( 12 , 13 , 32 , 33 ), however in Europe this spreading receives attention and is seen as a possible consequence of global climate changes ( 14 , 34 ).…”

“…Most of the D. immitis infections documented in Brazil are in coastal areas (7,29,30), although infections are not restricted to these environments (31). The geographical dispersion of the parasite D. immitis in Brazilian previously indene regions are scarce (12,13,32,33), however in Europe this spreading receives attention and is seen as a possible consequence of global climate changes (14,34). Thus, a broad epidemiological investigation must be conducted to monitor the prevalence of D. immitis in local dog populations by performing specific routine laboratory tests for detection and this filarioid identification.…”