Angiostrongylus vasorum in foxes (Vulpes vulpes) and wolves (Canis lupus italicus) from Abruzzo region, Italy

Abstract

In Europe wildlife animals such as the red fox ( Vulpes vulpes ) are considered the main reservoir for Angiostrongylus vasorum as well as a potential threat for domestic dog infection. Though this parasite is endemic in fox populations, data on A. vasorum infection in wolves ( Canis lupus italicus ) are still scant, having only recently been described in Northwestern Spain, in Italy, in Croatia and in Slovakia. Based on the rising number of cases of canine lungworm infection in Central Italy (Abruzzo region), the aim of the present study was to investigate the infection by A. vasorum in fox and wolf populations sharing the same geographical area of dogs. From October 2008 to November 2019, A. vasorum specimens were collected, through routine post-mortem examination, from 56 carcasses (44 foxes and 12 wolves). Adult parasites were searched for in the right side of the heart and in pulmonary artery of all carcasses. First stage of larvae (L1) was searched in faeces using the Baermann technique and in lungs by tissue impressions. Overall, 230 adult specimens were collected and identified on a morphological basis. To confirm the morphological identification, 4 adult specimens (n = 3 from fox, n = 1 from wolf) were molecularly identified as A. vasorum by amplification of partial fragment of nuclear 18S rRNA (~1700 bp) genes. The anatomo-pathological and parasitological examinations indicated the presence of A. vasorum in 33 foxes (75%) and in 8 wolves (66.7%). The level of prevalence of infested wolves was higher than the previous one reported in other European countries. Interestingly, the prevalence of infection in foxes herein recorded was higher than that described in dogs (8.9%) living in the same geographical area. This result may confirm the hypothesis that the spread of canine angiostrongylosis is linked to fox populations infection.

Angiostrongylosis in Animals and Humans in Europe

“…Greater understanding of the biology, ecology and epidemiology of this genus is needed if the prospects of future spread and disease in Europe are to be evaluated and managed. A. daskalovi [8,[58][59][60][61], A. dujardini [11,91,92], A. vasorum [13,[30][31][32][33][34][35][36][37].…”

“…Until the 1990s, 'hotspots' of infection in dogs and foxes were recognized in small parts of the United Kingdom (UK) and Denmark, with records also locally from France, Italy and Spain [13,30]. Since then, increasing distribution has been recorded in both dogs and foxes: for example, in the United Kingdom, there was northward spread in fox populations [31] and autochthonous cases in dogs distant from previously known endemic areas [16]; similarly, spread was recorded in Switzerland [32] and Denmark [14]; and in Italy, in both foxes and wolves [33,34]. Increasing awareness has probably contributed to this apparent spread, especially since the development of high-throughput diagnostic tests suitable for large prevalence surveys.…”

“…Awareness of veterinary clinicians ↑ Vigilance and new diagnostic tests lead to more records and apparent spread [30] Expansion and increased prevalence in foxes over time against robust baseline, not affected by clinical awareness [31][32][33][34] Fox urbanization Emergence in Western Europe followed rabies eradication and ↑ urban foxes, c.f. Echinococcus multilocularis [41] In U.K. 'hotspots', urban foxes were common long before emergence, which also coincided with relatively low populations due to scabies outbreaks [42] Gastropod invasion Emergence along with the invasion of Arion vulgaris (syn.…”

“…Longer-range dispersal ahead of spread in foxes, e.g., in the United Kingdom [16] New records in areas long subject to dog movements [33][34][35][36][37] Ambiguity in the links between A. vasorum spread and climatic and other factors makes it difficult to evaluate the prospects of further range expansion, and indeed, changes in prevalence and disease impact within the existing range. Climate warming is most likely to accelerate larval development within poikilothermic gastropod IHs [40], but it remains uncertain as to whether this will translate into the increased availability of infective larvae to DHs.…”

“…The detection of A. cantonensis in wildlife in Europe [10] and elsewhere [87], along with numerous surveys of A. vasorum in wild carnivores [31][32][33][34], point to the value of wildlife surveillance in detecting range expansion. Animals in zoological collections should be included in this, especially for A. dujardini [11,87] and also A. vasorum [29,[100][101][102].…”