Prevalence of Dirofilaria repens in dogs living in deltaic coastal plain of the Volturno River (Italy): a geographical risk model of infection

Abstract

The prevalence of vector-associated parasitic infections is high in central-southern Italy. The deltaic coastal plain of the Volturno River has been suspected, by veterinary practitioners, to have a high accidental incidence of Dirofilaria repens. Thus, the goal of this study was to evaluate the prevalence of dirofilariasis and other coinfections frequently described in dogs living in the Volturno area. Blood samples of 100 clinical asymptomatic dogs were examined using a Knott's technique and polymerase chain reaction in order to identify microfilariae. Other vector-borne coinfections were also investigated using ELISA kits. The results were analysed using statistical and Geographic Information System (GIS) software. Microfilariae of D. repens were detected in 10% of the dogs surveyed, with a presence of antibodies against Ehrlichia canis (4/10) and Dirofilaria immitis (1/10). Such high incidence should be considered in light of the zoonotic potential for D. repens and the support for more regular use of repellents to prevent the spread of this disease. The GIS analyses indicated that the study area provides suitable conditions to sustain populations of mosquito vectors and D. repens parasites throughout much of the year.

Emerging risk of Dirofilaria spp. infection in shelter dogs in southern Italy

“…The study was conducted in a dog shelter located in Castel Volturno ( Figure 1 ), a deltaic coastal plain of the Volturno River, an area where veterinary practitioners have reported a high incidence of D. repens infection ( 13 ).…”

“…The results of the questionnaire survey on heartworm and subcutaneous dirofilariosis addressed to veterinary practitioners throughout Italy ( 7 ) showed that at least one clinical case per year of cardiopulmonary dirofilariosis was diagnosed in dogs with frequent co-infestation by D. immitis and D. repens in Campania. Recent studies confirm the presence of autochthonous cases of D. immitis with a prevalence of approximately 0.1% ( 13 , 17 ). Based on the last two reports of two cases of heartworm disease (HW) detected during post-mortem examination of two roaming dogs ( 17 ) and a screening study in which 10% of dogs tested positive for D. repens ( 13 ), both studies from the urban area of Castel Volturno in the Campania region of southern Italy, the aim of the present study was to describe an outbreak of infection in a dog shelter from the same area.…”

“…Recent studies confirm the presence of autochthonous cases of D. immitis with a prevalence of approximately 0.1% ( 13 , 17 ). Based on the last two reports of two cases of heartworm disease (HW) detected during post-mortem examination of two roaming dogs ( 17 ) and a screening study in which 10% of dogs tested positive for D. repens ( 13 ), both studies from the urban area of Castel Volturno in the Campania region of southern Italy, the aim of the present study was to describe an outbreak of infection in a dog shelter from the same area.…”

“…In southern Italy, the number of autochthonous cases and foci of D. immitis in dogs has increased considerably ( 10 , 11 ). This also occurs in the Campania region, particularly in coastal areas, where infections with D. immitis and D. repens have been reported more frequently and the prevalence of D. repens has increased from 2% ( 12 ) to 10% ( 13 ). As with D. immitis , hunting dogs, stray dogs, and dogs housed in kennels are more exposed, with seroprevalence ranging from 0.2 to 4.4% ( 14 – 16 ).…”

Cutaneous filarioid nematodes of dogs in the United States: Are they emerging, neglected, or underdiagnosed parasites?

“…Dirofilaria repens is the primary species causing canine subcutaneous dirofilariosis, which is endemic in Europe, southeast Asia, and Africa (176,177). It is primarily of zoonotic importance but can be highly prevalent in dogs (178). Similar to other representatives of Dirofilaria, it can be transmitted by numerous mosquito species and may establish in the same areas suitable for D. immitis due to the possibility of competent vector sharing (173).…”