Is the European badger a new host for Dirofilaria immitis? The first records in Greece

Abstract

Dirofilaria immitis is a ubiquitous nematode parasite with zoonotic potential, transmitted by mosquitoes, that causes heartworm disease in various animal species. Dogs are the parasite’s typical final host, and wild carnivores represent the parasite’s reservoir in nature. Studies on D. immitis infections in wild animals are essential to assess infection pressure for domestic animals, and until now, there has been only one infection case reported in a European badger (Meles meles). The current report describes the first two European badger cases with cardiovascular dirofilariosis in Greece. Two adult male badgers were rescued in Heraklion and Chania, Crete Island, and admitted to “ANIMA -Wildlife Rehabilitation Centre” in Athens. The detailed clinical examination revealed that the first badger suffered from severe broncho-pneumonitis while the second one displayed clinical signs associated with severe brain trauma. Blood samples were taken for haematology and biochemistry analyses during their short hospitalisation period. In addition, different routine diagnostic tests were carried out, including heartworm antigen testing (ELISA) and the modified Knott’s test for microfilariae. Both badgers were positive in both tests. The animals died a few hours after their admission and the detailed necropsies followed, revealed the presence of three parasites in each animal’s right heart, morphologically identified as adults of D. immitis. These findings add the European badger in the list of additional potential reservoir hosts for D. immitis and highlight the potential role of wildlife for companion animals and human health.

Beyond Borders: Dirofilaria immitis Infection in Dogs Spreads to Previously Non-Enzootic Areas in Greece—A Serological Survey

“…The role of wild animals in the epizootiology of dirofilariosis should not be underestimated. It has been proven that D. immitis infects many wild mammalian species, such as golden jackals ( Canis aureus ), wolves ( Canis lupus ), coyotes ( Canis latrans ), red foxes ( Vulpes vulpes ), European wildcats ( Felis silvestris silvestris ), black bears ( Ursus americanus ), brown bears ( Ursus arctos ) and European badgers ( Meles meles ) [ 47 , 48 ]. In addition, cardiopulmonary dirofilariosis has been identified as one of the leading causes of death in wildlife animals [ 49 ].…”

“…However, until now, there is a lack of data regarding the exact epizootiological role of wildlife animals in transmitting D. immitis since their role as definitive hosts for this parasite has not been adequately investigated [ 47 ]. In Greece, there are limited studies, and the presence of the parasite has been documented in a golden jackal [ 50 ], a brown bear [ 51 ], and most recently in two European badgers [ 48 ]. In the latter study, the presence of microfilariae in both badgers was detected, thus corroborating this wildlife species as a competent host.…”

Wildlife and parasitic infections: A One Health perspective in Greece

“…These findings highlighted the role of this species as an additional reservoir host for D. immitis . In more detail, this study suggested that dirofilariosis occurs in the indigenous wildlife of Crete Island, an area which, based on the available data, currently, is not regarded as endemic for dirofilariosis ( Markakis et al, 2024 ). Interestingly, a recent ecological niche modeling analysis study for Culex pipiens , the main vector of D. immitis in Greece, revealed that the environment in Crete is suitable for the mosquito to complete its life-cycle and the future infection risk in that area is high ( Rodríguez-Escolar et al, 2024 ).…”

“… 94 6.4 b Touloudi et al (2015) Cestoda Echninococcus granulosus 273 1.1 Chaligiannis et al (2015) European badger ( Meles meles ) Protozoa Eimeria spp. 2 50.0 Liatis et al (2017) Nematoda Dirofilaria immitis 2 100 Markakis et al (2024) Brown rat ( Rattus norvegicus ) Protozoa Leishmania infantum 16 6.2 c Papadogiannakis et al (2010) 19 70.0 b , 0 d Tsakmakidis et al (2017) Black rat ( Rattus rattus ) Protozoa Leishmania infantum 12 50.0 b , 25.0 d Tsakmakidis et al (2017) House mouse ( Mus musculus ) Protozoa Leishmania infantum 66 50.0 b , 24.0 d Tsakmakidis et al (2017) European hedgehog ( Erinaceus europaeus ) …”

“… Markakis et al (2024) recently documented the first cases of dirofilariosis in two European badgers from Crete Island ( Table 2 ). While D. immitis infection has previously been demonstrated in Romania ( Ionică et al, 2017 ), this study in Greece presented compelling evidence of antigenemia, microfilariemia, and the presence of adult parasites in European badgers accompanied by cardiovascular symptoms.…”