The prevalence of Dirofilaria repens in cats, healthy dogs and dogs with concurrent babesiosis in an expansion zone in central Europe

Abstract

BackgroundDirofilaria repens is a mosquito-transmitted, filarial nematode parasitizing dogs, cats and other carnivores. Recently, this parasite has spread in central Europe, including Poland. The aim of the present study was to estimate the prevalence of D. repens in cats and dogs in different regions of the country and to investigate the occurrence and consequences of co-infection with another fast-spreading vector-borne parasite, Babesia canis.ResultsIn the period 2013–2015, 147 blood samples from cats from central Poland and 257 blood samples from dogs from central, northern, southern and western Poland were collected. Prevalence of D. repens was determined by amplification and sequencing of the 12S rDNA gene fragment. Among dogs, 94 samples originated from clinically healthy dogs from central Poland (Masovia) and 58 samples originated from dogs that were infected with B. canis. Prevalence of D. repens was compared between these two groups of dogs.For the first time D. repens was identified in a cat from central Europe (0.7 % [95 % CL: 0–4.1 %]). The DNA of the filarial endosymbiotic bacterium Wolbachia was detected in two cats (1.4 % [95 % CL: 0–5.5 %]). In dogs, the parasite was detected only in samples from central Poland (Masovia) (local prevalence = 38 % [95 % CL: 25.9–51.8 %]). Prevalence of D. repens was significantly higher in dogs with babesiosis (90 % [95 % CL: 81.6–94.5 %]). Co-infections of D. repens and B. canis were confirmed by sequencing in 30 dogs with babesiosis, but no co-infections were identified in healthy dogs from Masovia. Statistical analyses of blood parameters revealed that dogs with co-infections suffered more severe anemia and thrombocytopenia, but presented milder changes in biochemical parameters (i.e. less elevated concentration of alkaline phosphatase [ALP] and serum urea) suggesting lower risk of hepatic or renal failure in comparison to dogs infected only with B. canis.ConclusionsThese findings are important due to the spread of dirofilariosis and babesiosis in central Europe, as microfilaraemic dogs seem to be more prone to babesiosis. The possible protective effect of the nematode infection against hepatic or renal failure in canine babesiosis and its mechanisms require further investigations.

Dirofilaria repens—An etiological factor or an incidental finding in cytologic and histopathologic biopsies from dogs

“…Dogs with microfilaremia are more prone to contracting babesiosis. Interestingly, D repens might have a protective effect against hepatic or renal failure in canine babesiosis, as dogs with D repens and Babesia canis co‐infections presented milder biochemical analyte changes than dogs infected with only Babesia canis . Furthermore, mixed infections with D repens , Anaplasma phagocytophilum , and/or Babesia canis have been reported in clinically healthy dogs …”

Changes in erythrocytopoesis indices in dogs with babesiosis

“…The development of babesiosis in dogs is a complex process which is determined by a number of biological, natural-climatic and socioeconomic factors (Iguchi et al, 2014). The pathogenesis of this disease is determined by the specific type of pathogen and the corresponding reactions occurring in the organism of the affected animal, which, in turn, depend on the biology and life cycle of the Babesia canis and the conditions in which the interaction of the macro-and microorganism occurs (Al Izzi et al, 2013;Bajer et al, 2016;Piane et al, 2016). The peculiarity of the pathogenesis of the disease is the reproduction of the causative agent of babesiosis in the organism of a susceptible animal inside the erythrocytes of the capillaries in the internal organs, and then in the erythrocytes of the blood stream.…”

Vector-borne zoonotic pathogens in cats

“…However, the true prevalence of feline HWD is difficult to evaluate due to diagnostic difficulties, but infection in felines is detected in the same areas as canine HWD, which vary from 9 to 18% in unprotected dogs (Venco et al, 2011;Genchi et al, 2015). Information about the prevalence of D. repens in cats in Europe is also limited: the few studies performed in the continent show 1.6% prevalence rate in Italy and 0.7% prevalence rate in cats in central Poland (Traversa et al, 2010;Bajer et al, 2016). Because of the epidemiology of the disease, every cat living in the area where dogs are infected with Dirofilaria spp., should be considered at risk of infection.…”