Rapidly changing environments and an increase in human movement around the globe have contributed to a rise in new and emerging diseases, many of which are arthropod borne. The threat posed to the United Kingdom by such diseases is uncertain, and there is a real need to understand the distribution, seasonality and behaviour of potential vectors in the country. At present, there is no standard method for routine mosquito surveillance in the UK. Here we compared the catching efficiency of two carbon dioxide-baited traps, the CDC light trap and the MosquitoMagnet® Pro trap, for collecting British mosquitoes. Two of each type of trap were operated at four sites in central and southern England from June to September, 2003. To determine whether trap height affected collections, three light traps were operated at 1, 2.5 and 5 m above the ground in one site in 2004. Both types of trap were efficient at catching mosquitoes, collecting 5414 mosquitoes of 16 species. MosquitoMagnet® traps caught 2.7 times more mosquitoes than CDC light traps (P<0.001) and a wider range of species (16 species vs 11) than CDC light traps. Four to six times more female Culex pipiens s.l. were collected in light traps at 5 m (P<0.001) compared with traps at lower heights. MosquitoMagnet® traps ran continuously for up to 8 weeks, whilst the battery of a CDC light trap had to be replaced every 24 hrs. Although MosquitoMagnets® collected more specimens and a greater range of mosquito species, they were considerably more expensive, prone to breakdown and incurred higher running costs than the CDC light traps. MosquitoMagnets® are useful tools for collecting mosquitoes during longitudinal surveys during the summer months, whilst CDC light traps are to be preferred for rapid assessments of the presence or absence of mosquitoes, particularly the important species Culex pipiens.

Mosquito traps known as Mbita traps made from modified bednets according to a design developed in Kenya were compared with Centers for Disease Control (CDC) light traps for their ability to catch anopheline and culicine mosquitoes in several different villages in northern Tanzania. The results confirmed those recently reported in Kenya, that Mbita traps catch significantly fewer mosquitoes than CDC traps. Statistical analysis using a Poisson log linear model with random effects for the trap counts showed that the ratio of the catches with the two types of trap was not consistent in the different villages. Thus, we doubt whether the Mbita trap would be a reliable substitute for CDC traps. In one trial, the catches made at different hours of the night with the two types of trap indicated that in villages where insecticide treated nets (ITNs) had been used for some years, somewhat more of the Anopheles biting occurred early and late in the night, whereas in villages with no history of ITN use, biting was concentrated in the middle of the night. This suggests that behavioural adaptation to avoid contact with ITNs may be beginning to evolve.