Dirofilaria repens in dogs and humans in Lithuania

Vytautas Sabūnas,Jana Radzijevskaja,Birutė Karvelienė,Povilas Sakalauskas,Jolanta Žiliukienė,Algimantas Paulauskas,Saulius Petkevičius,Indrė Lipatova

doi:10.1186/s13071-019-3406-y

Vytautas Sabūnas, Jana Radzijevskaja + Show 6 more

Open Access

https://doi.org/10.1186/s13071-019-3406-y

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Abstract

BackgroundIn Lithuania, the first case of canine subcutaneous dirofilariosis was recorded in 2010. Since then, an increasing number of cases of canine dirofilariosis have been documented in different veterinary clinics throughout the country. Human dirofilariosis was diagnosed in Lithuania for the first time in September 2011. However, to the authors’ knowledge, there are no published data on the presence and prevalence of autochthonous dirofilariosis in dogs and humans in the country. The present study provides information about the predominant species and prevalence of Dirofilaria in dogs and describes the cases of human dirofilariosis in Lithuania. It also outlines PCR detection of the bacterial endosymbiont Wolbachia that contributes to the inflammatory features of filarioid infection.ResultsA total of 2280 blood samples and six adult worms from pet and shelter dogs were collected in the central and eastern regions of Lithuania in 2013–2015. Based on their morphological appearance, morphometric measurements and molecular analysis, all the adult nematodes were identified as Dirofilaria repens. The diagnosis of microfilariae in blood samples was based on blood smear analysis and Knott’s test. The PCR and sequence analysis of the ribosomal DNA ITS2 region and cox1 gene confirmed the presence of D. repens. Overall, 61 (2.7%) of the 2280 blood samples were found to be positive for the presence of D. repens. The infection rate of D. repens was significantly higher in shelter dogs (19.0%; 19/100) than in pet dogs (1.9%; 42/2180) (χ2 = 100.039, df = 1, P < 0.0001). Forty-nine DNA samples of D. repens-infected dogs were tested for the presence of the bacterial endosymbiont Wolbachia and, of these, 40 samples (81.6%) were found to be positive. Three ocular and six subcutaneous cases of human dirofilariosis were diagnosed in Lithuania in the period 2011–2018.ConclusionsTo the authors’ knowledge, this is the first report of autochthonous D. repens infection in dogs and humans in Lithuania. The present data demonstrate that D. repens is the main etiological agent of dirofilariosis in Lithuania. The DNA of the filarioid endosymbiotic bacterium Wolbachia was detected in the vast majority of dogs infected with D. repens.

Highlights

In Lithuania, the first case of canine subcutaneous dirofilariosis was recorded in 2010
To the authors’ knowledge, this is the first report of autochthonous D. repens infection in dogs and humans in Lithuania
The present data demonstrate that D. repens is the main etiological agent of dirofilariosis in Lithuania

Summary

Introduction

In Lithuania, the first case of canine subcutaneous dirofilariosis was recorded in 2010. The present study provides information about the predominant species and prevalence of Dirofilaria in dogs and describes the cases of human dirofilariosis in Lithuania. It outlines PCR detection of the bacterial endosymbiont Wolbachia that contributes to the inflammatory features of filarioid infection. Dirofilariosis is an emerging vector-borne parasitic zoonotic infection caused by nematodes of the genus Dirofilaria. The majority of cases in humans and animals are caused by two Dirofilaria species, Dirofilaria repens and Dirofilaria immitis, both of which can infect numerous mammalian species [4]. Dirofilariosis caused by D. repens and D. immitis has been reported in wild carnivores, e.g. wolves

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