A Peculiar Distribution of the Emerging Nematode Angiostrongylus cantonensis in the Canary Islands (Spain): Recent Introduction or Isolation Effect?

Abstract

Angiostrongylus cantonensis is an emerging zoonotic nematode recognized as the leading cause of eosinophilic meningitis in the word. After its discovery in China, it was recorded in 30 countries worldwide. Recently, it has expanded to new areas such as South America and it has been recently found in the Atlantic island of Tenerife (Canary Islands). In order to characterize the distribution of A. cantonensis in the Canary Islands, the lungs of 1462 rodents were sampled in eight islands of the archipelago over 13 years and were then analyzed for A. cantonensis. Remarkably, the parasite was detected only in Tenerife, in Rattus rattus (19.7%) and Rattus norvegicus (7.14%). They were concretely in the northern part of the island, which had a warmer and more humid climate than the south and main cities. The absence of this nematode in other islands with similar environmental conditions could be explained by an isolation effect or by a recent introduction of the parasite in the islands. Besides, the presence in Tenerife of the most invasive lineage of A. cantonensis reinforced the hypothesis of a recent introduction on this island. This study highlights the need to implement control measures to prevent the expansion to other areas in order to avoid the transmission to humans and other animals.

Angiostrongylosis in Animals and Humans in Europe

“…The presence of A. cantonensis in R. rattus from the island of Tenerife, Canary Islands, was recorded in 2010 [9], but the islands are distant from mainland Europe, and this can be considered an extension of the African range. In this Atlantic archipelago, the two rat species present, R. rattus and R. norvegicus, act as DHs for A. cantonensis [78], and the mollusc species P. lamarckii, Cornu aspersum and Theba pisana were identified as IHs [63]. A survey carried out in the eight islands of the archipelago demonstrated the presence of A. cantonensis only in Tenerife [78], one of the two most populated islands.…”

“…In this Atlantic archipelago, the two rat species present, R. rattus and R. norvegicus, act as DHs for A. cantonensis [78], and the mollusc species P. lamarckii, Cornu aspersum and Theba pisana were identified as IHs [63]. A survey carried out in the eight islands of the archipelago demonstrated the presence of A. cantonensis only in Tenerife [78], one of the two most populated islands. The Canary Islands play an important role as a maritime connection between European, African, and American ports, that could imply a risk of spread of A. cantonensis to new locations.…”

“…In the absence of solid understanding of the ecological and climatic factors underlying suitability for the establishment of A. cantonensis in Europe, and the behavioural and dietary factors locally important to human exposure, the future trajectory of AEM on the continent, and potential bioclimatic limits to its eventual range, are difficult to predict. Climate and environment are certainly important to parasite distribution, including on Tenerife [78], and environmental correlates of existing distribution have been used elsewhere, alongside climate change projections, to predict areas at risk of future invasion [88]. Globally, similar models have suggested a decrease in the total habitat suitable for A. cantonensis under climate change [89], but in spite of this, continued spread and introduction events potentially increase actual range [90].…”

“…Maps show the location of reports by country (and, for A.cantonensis, by island), and not distribution within countries or islands. Sources: A. cantonensis[10,78], A. chabaudi[47][48][49], A. daskalovi[8,[58][59][60][61], A. dujardini[11,91,92], A. vasorum[13,[30][31][32][33][34][35][36][37].…”

What do we know about Angiostrongylus cantonensis in Spain? Current knowledge and future perspectives in a globalized world

“…Moreover, a risk factor shared between Canary Islands and the Iberian Peninsula that favour the human infection is related to gastronomic traditions since the consumption of snails and slugs is a common practice in western Europe that needs to be considered (Martin-Alonso et al, 2011Martín-Carrillo et al, 2021). Additionally, climatic variables (e.g.…”