The Andalusian government ignored technical reports that warned that outbreaks of the West Nile virus could appear in the region, as has happened this summer in Seville, causing two deaths and 42 hospitalizations – eight of which required intensive care – due to meningoencephalitis. The reports were produced by the Doñana Biological Station, which is part of the CSIC public research agency, and called on the regional authorities to implement programs to control Culex mosquitoes, whose bites spread the virus, via fumigations that would kill the insects’ larvae.
But the studies fell on deaf ears, and neither the junta, as the regional government is known, nor the Seville provincial authority nor the local councils in the areas bordering the Guadalquivir River have taken any actions that would have minimized the current outbreak, which is the most serious seen in Spain until now.
The junta, which was previously run by the Socialist Party (PSOE) but has been in the hands of the conservative Popular Party (PP) and center-right Ciudadanos (Citizens) since early 2019, requested reports in 2011 and 2014 after residents raised concerns about outbreaks: one in 2010, with two people infected in Cádiz, and another in 2013, when dozens of horses were infected. Years later, in 2016, another outbreak was registered in Coria del Río, Seville, with three people infected but no deaths. Despite the series of outbreaks, the Andalusian government did not react.
For now, the regional government is only “authorizing fumigation plans” carried out by local councils
The scientists behind the reports, who have been studying the West Nile virus since 2003, presented two draft agreements with plans to control the mosquito population, at a cost of between €365,000 and €500,000 a year. But neither the health, environment, agriculture and governance departments at the junta made a move.
“They answered the Doñana Biological Station, but we still don’t know how,” explains the cabinet chief at the Andalusian department of agriculture, fishing and sustainable development, Mónica España. The department has not clarified whether it will change course and from now carry out preventive fumigations and put a plan in place to avoid new outbreaks. For now, España says, the regional government is only “authorizing fumigation plans” carried out by local councils in areas located close to the protected area of Doñana.
At the same time, the health department is arguing that fumigations are the responsibility of the local councils, which in turn are calling on the junta to fund and coordinate this work, given that they lack specialized technicians to carry it out. “The junta should take the lead,” said local mayors Modesto González and Manuel Bejarano on Wednesday.
The outbreak is now affecting 12 municipalities, including the city of Seville itself, with both humans and horses having been infected.
An 85-year-old woman and a 77-year-old man died last week after having been bitten by mosquitoes carrying the virus, and there are still six people receiving treatment in the ICU. Experts calculate that around 4,000 people have been infected, given that just 1% of carriers require hospitalization. This summer has also seen 32 horses infected between Seville and Huelva provinces.
As well as the costs to health, the local economy in these areas has retreated after the authorities called on residents to stay at home. Blood donations have also been suspended.
Rain, stagnant water and the lockdown
Experts point to spring rainfall and stagnant water – in part due to the coronavirus lockdown – as the causes of the 30% rise in the mosquito population in the area of the outbreaks. “If you don’t use larvicides in spring, there’s no other option but to use more toxic products for the adult mosquitoes, provided they don’t affect humans, pets or the water network,” explains Jordi Figuerola, a researcher from the Doñana Biological Station specializing in field ecology and the dynamics of infectious disease transmission via mosquitoes. This spring, the insects have reproduced like never before around the municipalities of Coria and La Puebla del Río, both of which are within a 10-kilometer radius of the Andalusian capital city, Seville.
Figuerola and another 10 researchers from the Carlos III Health Institute and the University of Utrecht, among other centers, collected 26,666 Culex mosquitoes to study the transmission of the West Nile virus in Andalusia. In an article that is due to be published in the magazine Transboundary and Emerging Diseases, the researchers suggest reducing the mosquito population and introducing mammals such as wild boar on the outskirts of towns and villages as a solution.
So why have the numbers grown so much this year? “From carelessness and agricultural activities, to irrigated land with a lot of rice fields, gardens in houses, planters, small and large tanks…,” explains Miguel Ángel Jiménez, a virologist from the National Institute of Agrarian and Food Research and Technology (INIA). “It’s possible that the lockdown caused a temporary abandonment. We have to monitor the mosquitoes so that this doesn’t happen. Counting mosquitoes might seem like a crazy thing to do… but this is why it is done.”
English version by Simon Hunter.