Modelling the spatial risk of malaria through probability distribution of Anopheles maculipennis s.l. and imported cases

Malaria remains one of the most important infectious diseases globally due to its high incidence and mortality rates. The
influx of infected cases from endemic to non-endemic malaria regions like Europe has resulted in a public health concern
over sporadic local outbreaks. This is facilitated by the continued presence of competent Anopheles vectors in non-
endemic countries.
We modelled the potential distribution of the main malaria vector across Spain using the ensemble of eight
modelling techniques based on environmental parameters and the Anopheles maculipennis s.l. presence/absence data
collected from 2000 to 2020. We then combined this map with the number of imported malaria cases in each
municipality to detect the geographic hot spots with a higher risk of local malaria transmission.
The malaria vector occurred preferentially in irrigated lands characterized by warm climate conditions and moderate
annual precipitation. Some areas surrounding irrigated lands in northern Spain (e.g. Zaragoza, Logroño), mainland areas
(e.g. Madrid, Toledo) and in the South (e.g. Huelva), presented a significant likelihood of A. maculipennis s.l. occurrence,
with a large overlap with the presence of imported cases of malaria.
While the risk of malaria re-emergence in Spain is low, it is not evenly distributed throughout the country. The four
recorded local cases of mosquito-borne transmission occurred in areas with a high overlap of imported cases and
mosquito presence. Integrating mosquito distribution with human incidence cases provides an effective tool for the
quantification of large-scale geographic variation in transmission risk and pinpointing priority areas for targeted
surveillance and prevention.