Stray dogs of Sofia (Bulgaria) could be an important reservoir of heartworm (Dirofilaria immitis)

Abstract

SummaryDirofilaria immitis (heartworm) is a zoonotic and an emerging disease, expanding in Europe. In Bulgaria, the presence of the parasite has been described in many regions. However, canine heartworm has hardly been evaluated in the capital of the country and, therefore, the aim of this study was to evaluate the prevalence and distribution of canine heartworm in Sofia. Eighty stray dogs from the city of Sofia and the metropolitan area were analysed for circulating D. immitis antigens. The prevalence was 31.25 %, being 34.7 % in the metropolitan area and 25.8 % in the city of Sofia. The current results are among the highest reported in the country. This could be due to the lack of prophylactic measures against infection in these dogs, but also to the spread of D. immitis into non-endemic countries. Stray dogs may act as an important reservoir of heartworm being a risk for client-owned animals and for the development of pulmonary dirofilariosis in inhabitants. The results show the need to establish further epidemiological studies and prophylactic campaigns for stray and client-owned animals, as well as to create awareness campaigns about the severity and importance of this disease for both animals and humans.

Comparison of Diagnostic Tools for the Detection of Dirofilaria immitis Infection in Dogs

“…In the last two decades, reports of clinical cases of heartworm (HW) infection in dogs have increased even in non-endemic areas with new endemic foci detected in the Mediterranean region [ 8 , 9 , 10 ]. However, several studies have recorded a large variability in prevalence data [ 11 , 12 , 13 ], which depends on epidemiological factors (e.g., presence and abundance of competent vectors and absence of chemoprophylaxis treatments) as well as on the diagnostic methods employed. Indeed, the frequency of Dirofilaria spp.…”

“…However, several studies have recorded a large variability in prevalence data [11][12][13], which depends on epidemiological factors (e.g., presence and abundance of competent vectors and absence of chemoprophylaxis treatments) as well as on the diagnostic methods employed. Indeed, the frequency of Dirofilaria spp.…”

Dirofilaria immitis in Bulgaria: the first genetic baseline data and an overview of the current status

“…Further studies will be aimed at screening of the additional gene segments in causative agents of canine dirofilariosis in Bulgaria and adjacent countries of southeastern Europe to better elucidate dissemination patterns linked to their recent expansion across the region. Stoyanova et al (2019) n=number of examined; HW = heartworm; un = unknown; (ex/pos) = D. immitis examined/positive if less than 10 samples were collected Table 1. Review on the occurrence of Dirofilaria immitis in dogs and wild-living carnivores in Bulgaria.…”

“…In the region of Eastern Europe, Bulgaria, Croatia, Romania and Serbia are currently recognized as endemic countries, and sporadic autochthonous cases were also reported from the Czech Republic, Slovakia and Hungary (Genchi et al, 2020). Among the main factors that have facilitated the spread of heartworm disease in Europe during the last decades may be the global warming, which caused an increase in abundance of mosquito populations, and lengthening the transmission season (Sassnau et al, 2014); the high number of wild hosts, particularly golden jackals, and untreated stray dogs (e.g., Ionică et al, 2016;Stoyanova et al, 2019); and the launch of the Pet Travel Scheme in 2000, which has allowed easier movement of pet animals throughout the European Union (Trotz-Williams & Trees, 2003). In Bulgaria, there is a clear trend of raising D. immitis prevalences in dogs and wild carnivores over the last decade (e.g., Panayotova-Pencheva et al, 2016;Iliev et al, 2017;Stoyanova et al, 2019).…”

“…In Bulgaria, there is a clear trend of raising D. immitis prevalences in dogs and wild carnivores over the last decade (e.g., Panayotova-Pencheva et al, 2016 ; Iliev et al, 2017 ; Stoyanova et al, 2019 ). Nonetheless, no data are available so far about the genetic structure and polymorphism of Dirofilaria heartworms circulating in the country.…”