Zoonotic Dirofilaria immitis and Dirofilaria repens infection in humans and an integrative approach to the diagnosis

• Published in: Acta tropica 2021-11, Vol.223, p.106083-106083, Article 106083
• Main Authors: Mendoza-Roldan, Jairo Alfonso, Gabrielli, Simona, Cascio, Antonio, Manoj, Ranju R.S., Bezerra-Santos, Marcos Antonio, Benelli, Giovanni, Brianti, Emanuele, Latrofa, Maria Stefania, Otranto, Domenico
• Format: Article
• Language: English
• Subjects: Canine heartworm disease; Dirofilariasis; Dogs; Humans; One Health; Vector-borne zoonosis
• ISSN: 0001-706X; 1873-6254
• DOI: 10.1016/j.actatropica.2021.106083

•In the Pelagie islands, human and dog exposure to D. immitis (Di) and D. repens (Dr) is overlapping.•Di and Dr seroprevalences were 7.9% and 4% in Linosa, 7.8% and 19.9% in Lampedusa, respectively.•4/397 human blood samples scored molecularly positive for Dirofilaria spp. by qPCR (3 Di+1 Dr).•Wolbachia was detected in 6 human samples, clustering along with other C supergroup filarioids.•In canine dirofilarioses endemic areas, humans are exposed highlighting the importance of One Health. Dirofilariosis by Dirofilaria immitis and Dirofilaria repens is endemic in dogs from countries of the Mediterranean basin. Both species may infect humans, with most of the infected patients remaining asymptomatic. Based on the recent description of the southernmost hyperendemic European focus of heartworm disease in dogs from the Pelagie archipelagos, we performed a serological and molecular survey in human population of that area. Human blood samples were collected in the islands of Linosa (n=101) and Lampedusa (n=296) and tested by ELISA and molecular test for the detection of D. immitis and D. repens. Samples were also screened for filarioid-associated endosymbionts, Wolbachia sp. The seroprevalence of D. immitis and D. repens was, respectively, 7.9% and 3.96% in Linosa, and 7.77% and 19.93% in Lampedusa. Out of 397 human blood samples tested molecularly, 4 scored positive (1%) for Dirofilaria spp. by qPCR (i.e., three for D. immitis and one for D. repens) and 6 (1.5%) for Wolbachia. Of the qPCR positive for Dirofilaria spp., only D. repens was amplified by cPCR and was positive for Wolbachia. In the phylogenetic analysis, the sequence of Wolbachia detected in D. repens positive samples clustered along with other C supergroup filarioids. Our results overlap with the recent prevalence data collected on dogs from the same area, where D. immitis is prevalent in Linosa and D. repens prevails in Lampedusa. Molecular detection of D. immitis in human blood is quite unusual considering that humans are dead-end hosts for dirofilarial infection and most of the human cases described so far in Europe were ascribed to D. repens. An integrative diagnostic approach using serum analysis and Wolbachia detection is also presented. In endemic areas for canine dirofilarioses humans are exposed to the infection, suggesting the importance of One Health approach in diagnosing, treating and controlling this zoonotic parasitosis. [Display omitted]