Dirofilaria immitis and Dirofilaria repens in mosquitoes from Corsica Island, France

Abstract

Background Dirofilaria immitis and Dirofilaria repens are the main causative agents of heartworm disease and subcutaneous dirofilariasis in domestic and wild canids, respectively. Both pathogens have zoonotic potential and are transmitted by mosquitoes. The present study aimed to determine the transmission period, prevalence and diversity of Dirofilaria spp. vectors from endemic areas of Corsica (France). Methods A monthly point data model based on average temperature recorded by four meteorological stations during 2017 was used to calculate the Dirofilaria transmission period. From June to September 2017, female mosquitoes (n = 1802) were captured using Biogents® Sentinel 2 traps lured with carbon dioxide and BG-Lure™ or octanol. Mosquitoes were identified to species level, pooled accordingly, and screened using multiplex real-time qPCR to detect D. immitis and D. repens. Results The monthly point data model showed the possible transmission of Dirofilaria spp. from the third week in May to the last week in October in the studied area. Mosquitoes were identified as Ochlerotatus caspius (n = 1432), Aedes albopictus (n = 199), Culex pipiens sensu lato (n = 165) and Aedes vexans (n = 6) and were grouped into 109 pools (from 1 to 27 specimens, mean 11.4 ± 0.7), of which 16 scored positive for Dirofilaria spp. (i.e., n = 13; estimated infection rate [EIR] = 1.1% for D. immitis and n = 3; EIR = 0.2% for D. repens). Specifically, 6 (i.e., EIR = 3.8%) of 15 pools of Ae. albopictus were positive for D. immitis, 2 of 14 of Cx. pipiens s.l. were positive for D. immitis and D. repens, respectively, and 8 of 77 pools of Oc. caspius were positive for D. immitis (i.e., n = 6; EIR = 0.4%) and D. repens (i.e., 2; EIR = 0.1%). The highest mosquito infection rate was recorded in July (EIR = 2.5%), then in June (EIR = 1.3%) and September (EIR = 0.6%). Conclusions The data suggest that both Dirofilaria species are endemic and occur possibly in sympatry in the studied area in Corsica, highlighting the need to implement preventive chemoprophylaxis and vector control strategies to reduce the risk of these filarioids in dog and human populations. Graphical Abstract

The Presence of Dirofilaria immitis in Domestic Dogs on San Cristobal Island, Galapagos

“…The presence of an endemic cycle for D. immitis depends on the presence of suitable definitive hosts (dogs), vectors (mosquitoes) and the nematodes. The presence and abundance of mosquitoes and the development of D. immitis larvae in mosquitoes are dependent on climatic factors, the most important being the temperature and availability of mosquito breeding sites [51,52]. Hence, climate and weather have a significant impact on the prevalence of canine heartworm.…”

“…Although the Knott's test has been shown to be less sensitive than the antigen test [51,52], the method has several advantages: (i) it allows the detection of other filarial species; (ii) it is more specific; (iii) it is cheaper; and (iv) it directly demonstrates the reservoir role of dogs, which was in fact our main rationale for this study. However, antigen detection-based methods can also detect occult heartworm infection even if microfilariae are not present in the blood [53,61,64,65].…”

What Has Happened to Heartworm Disease in Europe in the Last 10 Years?

“…pipiens and Och. caspius were identified as vectors for D. immitis [154]. In Germany, D. immitis larvae were detected in Cx.…”

Hematological parameters of dogs for parasitism Dirofilaria immitis

“…It is known that heartworm disease is common on most continents of the globe. However, the main distribution areas of the invasion are countries with warm and temperate climates and tropical areas around the world, including southern Europe (Dantas-Torres & Otranto, 2013;Genchi et al, 2019;Genchi & Kramer, 2020;Younes et al, 2021).…”