Accidental importation of the vector of Chagas disease, Triatoma rubrofasciata (De Geer, 1773) (Hemiptera, Reduviidae, Triatominae), in Europe.

Members of the subfamily Triatominae (Hemiptera; Reduviidae) are vectors of American trypanosomiasis, also called Chagas disease. These insects feed on blood and are capable of transmitting protozoa belonging to the genus Trypanosoma (Kinetoplastea), with T. cruzi (Chagas, 1909) being the most important vector for human and companion animal disease. Vector-borne transmission can occur through contamination of a mucous membrane or a skin opening by triatomine fecal material after a bite. Another important means of transmission is oral ingestion of contaminated unpasteurized food or drink that contains the triatomine insect or its fecal material. Most species of Triatoninae are distributed in the Americas, but a few are found in the Far East and India. One of them, Triatoma rubrofasciata, is widely distributed worldwide (Dujardin et al. 2015). The unique reference to T. rubrofasciata near Europe is from the island of Santa Maria, the southeastern-most in the Azores archipelago with a humid subtropical climate. The assignment of its presence to Europe (Schofield and Galvão 2009) would be confusing or erroneous due to the location of this Portuguese archipelago with respect to North Africa and Europe, in the middle of the Atlantic Ocean. The first known citation there occurred in 1979 (Lent and Wygodzinsky 1979), but the authors did not refer to any collection data (point/date). The presence of T. rubrofasciata seems stable in the Azores, as it was included as part of the fauna of the island of Santa Maria in 2010 but, surprisingly, the species has not been collected in the rest of the islands, although it has remained in the Azores for at least 31 years (1979-2010) (Borges et al. 2010). Triatoma rubriofasciata is considered to be a poor vector of T. cruzi and it was associated with transmission in only three cases in the Americas (Lent and Wygodzinsky 1979) but not in China or Vietnam, where the species is more abundant (Hieu et al. 2019), thus it is rarely associated with T. cruzi transmission. This may be due to the long defecation timing of this species that lowers the transmission possibility to mammal hosts (Braga and Lima 1999). Nevertheless, in the Far East, this species has become a public health problem due to the numerous bites that can become more severe by swelling, itching, and secondary infection (Hieu et al. 2019, Shi et al. 2020). Several anaphylactic reactions have also been reported in Hawaii and China, (Wang and Peng 2006, Anderson and Belnap 2015). In the Far East, T. rubrofasciata is found in all habitat types, especially in urban and peri-urban and to a lesser extent in rural areas (Dujardin et al. 2015, Hieu et al. 2019). In buildings, vector abundance decreases with increasing floor levels (Hieu et al. 2019). The specimen was studied morphologically and the taxonomical identification was conducted on the basis of the key diagnostic characters (Lent and Wygodzinsky 1979):