Natural Infection of Culex theileri (Diptera: Culicidae) with Dirofilaria immitis (Nematoda: Filarioidea) on Madeira Island, Portugal

Abstract

Field and laboratory studies were performed to verify whether Culex theileri Theobald functions as a natural vector of Dirofilaria immitis (Leidy) on Madeira Island, Portugal. CO2-baited light traps (EVS traps) were use to sample mosquitoes monthly basis between February 2002 and February 2003 in the area of Quebradas (Funchal). Three mosquito species were captured, including 58 Culex pipiens L., 790 Cx. theileri, and three Culiseta longiareolata (Macquart). Only C. theileri tested positive for D. immitis. The presence of this filarial worm was detected by direct observation, infectivity assay dissection technique, and polymerase chain reaction methods. Infected mosquitoes were recovered in October and December 2002 and January 2003. These data provide evidence that Cx. theileri could be the main vector of D. immitis in Funchal, Madeira.

Molecular Characterization of Culex Theileri from Canary Islands, Spain, a Potential Vector of Dirofilaria Immitis

“…For this reason, this finding, together with the report in Madeira island [8], implies a dirofilariosis transmission complexity in Southern Europe markedly higher than that considered so far. However, higher vector potential of a mosquito species in a region or in different regions could be elucidated by ecological factors such as geographical features, season a climate, and also host preference of mosquito species [56].…”

“…Nevertheless we cannot ruled out that most abundant captures, both of Cx. theileri and other culicid species could reveal higher prevalences like other studies have demonstrated (to 8.6% have been cited in different mosquito species have demonstrated [8,9,[45][46][47].…”

“…pipiens haplotype H1 [25], which is not present in the Canary Islands, considering that its real vectorial competence has been recently demonstrated in other two endemic areas, the nearby island of Madeira [8] and Irán [9] we can argue that Cx. theileri is the, or one of the culicid vector species involved in the transmission of D. immitis in the canine population of the Canary Islands.…”

“…theileri has been incriminated in the transmission of D. immitis in the island of Madeira [8] and in the Ardebil province of Iran [9]. In the latter study has shown that this mosquito is the most abundant species and the main vector of the parasite.…”

“…pipiens and Cx. tritaenorhynchus, are assumed to be involved in the transmission of dirofilariosis in other endemic areas [5][6][7][8].…”