Impacts of urbanisation level and distance from potential natural mosquito breeding habitats on the abundance of canine dirofilariosis

Abstract

Dirofilariosis is an emerging mosquito-borne veterinary and medical problem in the Northern hemisphere. The ecological investigation of 56 canine dirofilariosis cases in new endemic locations was performed in Szeged, Hungary. The aim was to analyse the influence of the spatial patterns of dog abundance and the potential mosquito breeding habitats on the spatial occurrence patterns of dirofilariosis in the city of Szeged. The limnoecological characterisation was based on the fluvial habitat classification of Amoros of natural water bodies; the built environment was evaluated using the UrbanisationScore urbanisation intensity measuring software. Dirofilaria immitis accounted for 51% and D. repens for 34.3% of the dirofilariosis cases, and in 20% of the cases only the Knott's test was positive. It was concluded that most of the cases were related to locations with a medium to high urbanisation index, although the proximity of mosquito-bearing waters also played an important role in the observed spatial infection patterns. We found that the distance from potential mosquito habitats and the urbanisation intensity determine the abundance of dirofilariosis in urban environments. Key words: Dirofilaria immitis, Dirofilaria repens, urbanisation intensity, Amoros classificationDirofilariosis caused by Dirofilaria immitis and D. repens is one of the most important emerging parasitic, mosquito-borne diseases in the oceanic and temperate climate areas of Europe (Raccurt, 1999;

The current situation of canine dirofilariosis in Hungary

“…Mixed Dirofilaria infections were detected in 11 (3.2%) dogs in our study. Trájer et al (2016) also found 5 coinfected dogs in the southern part of Hungary where 18 dogs were infected with D. immitis and 12 out of 56 with D. repens. These findings show that there is no spatial segregation of the two filarioid species in the given areas.…”

“…According to previous Hungarian reports, heartworm infection had been diagnosed pathologically only in dogs imported from the USA until 2000 (Boros et al 1982;Vörös et al 2000). Following the first autochthonous canine heartworm case (Jacsó et al, 2009), a few dozens of infected dogs have been reported (Farkas et al 2014;Túri and Hetyey 2014;Bacsadi et al 2016;Trájer et al 2016;Vörös et al 2017;Bagi et al 2017). All of them were considered autochthonous because these animals had been born in Hungary and had never left the country.…”

“…Jacsó et al (2009) reported the first autochthonous D. immitis infection of a local dog which lived in the eastern part of the country. Since that time, the number of confirmed heartworm infections has increased (Farkas et al 2014;Túri and Hetyey 2014;Bacsadi et al 2016;Trájer et al 2016;Vörös et al 2017;Bagi et al 2017) and worms were found during the necropsy of a ferret (Molnár et al 2010), some red foxes and golden jackals (Tolnai et al 2014).…”

Xenomonitoring of Mosquitoes (Diptera: Culicidae) for the Presence of Filarioid Helminths in Eastern Austria

“…Dirofilaria immitis was not identified in the present large-scale survey, confirming previous results that this parasite has not yet established itself in Eastern Austria [ 10 ]. This pathogen has however been confirmed in dogs [ 22 , 23 , 25 ] and in mosquitoes [ 26 , 27 ] in Slovakia and Hungary in the vicinity of our study area.…”

“…To date, all D. repens positive mosquitoes have been collected in close proximity to the Slovakian (this study) and the Hungarian borders [ 2 ]. In both Slovakia and Hungary, D. repens is known to be endemic with a prevalence above 10% in dogs in the Bratislava area, close to the Austrian border [ 22 , 23 ]. Previous metadata analysis has shown that most reported but also potential autochthonous findings in dogs were in Eastern Austria [ 10 ].…”