Risk maps could predict West Nile virus spread

MALAGA, Spain—Researchers of the Biogeography, Diversity, and Conservation Group at the University of Malaga (UMA) have developed risk models for West Nile virus. These models, which are based on historical incidence data, could be able to predict areas of future outbreaks a year in advance, as well as detect their intensity.

Using modeling based on fuzzy logic and artificial intelligence, the researchers analyzed the incidence of West Nile in Europe in 2017 to explain the “abnormally high” data of 2018, the year with the highest number of cases registered so far — a total of 1605. The results have been published in PLOS Neglected Tropical Diseases.

“Based on the analyzed data, we could successfully predict the places where the disease appeared, the intensity of outbreaks and the time they occurred,” said Raimundo Real, scientist in the Animal Biology Department of UMA.

Real asserted that anticipating future outbreaks of the disease could aid in the ability to take preventive measures in specific risk areas. These measures include early spraying against mosquitos, advising the population on measures to avoid bites, or controlling the water points where mosquitoes breed. Healthcare centers could also be warned about the possible disease incidence in the area, which would contribute to early diagnosis and improving prognosis in infected patients.

For the development of these risk maps, the researchers used a spatial model related to bird migration routes. They also determined that the environmental risk factors include high temperatures, presence of river courses, low altitude areas, and the presence of certain livestock facilities like stables and poultry farms, which are the most favorable factors for the spread of West Nile.

“We have observed that high temperatures speed up the life cycles of mosquitoes, shortening their gonotrophic cycle — period between the time mosquitoes feed on blood and the time they feed again — therefore, in warmer areas mosquito bite rate is also higher, facilitating the transmission of the virus,” emphasized Real. “In 2017, the outbreaks began in the lower areas of large river basins and spread to higher areas, which highlights the importance of river basins in the propagation of outbreaks.”