A 76-year-old woman from El Prat de Llobregat was admitted to the Bellvitge hospital this September for an illness which, pending confirmation of the diagnosis, is attributed to the West Nile virus. As a result of this case, screening for the virus has begun in all blood donations in Catalonia to avoid possible contagion in transfusions.
In addition, “all care centers, both primary and hospital, have been notified so that they are alert to detect new possible cases”, the Department of Health reported yesterday.
The patient, who needed admission to the hospital, is “currently in a socio-health center in the process of recovery, since, beyond the infection, her state of health is delicate”, reported a Health spokesperson.
West Nile virus is transmitted by mosquito bites that have acquired the infection from a bird. It is not transmitted from person to person – except through donations – so it is ruled out that it could cause an epidemic. Nor is it transmitted from one person to another through mosquitoes. When a person becomes infected, the virus must first have passed from a bird to a mosquito and then from the mosquito to the person.
The virus, originally from sub-Saharan Africa, is already endemic in bird populations in Catalonia. In addition, climate change favors the increase in the populations of mosquitoes that can transmit it, of the Culex genus. For this reason, it is expected that the number of cases in people will increase in the coming years, especially at the end of summer and at the beginning of autumn, following the annual cycle of activity of Culex mosquitoes.
The first two cases diagnosed in Catalonia, which were unrelated, were notified in Reus in September last year. What has now been detected in Bellvitge is the third to be announced. However, the real number of infections must be higher, since the vast majority are not diagnosed.
“The case is currently declared as probable due to the difficulty of making a definitive diagnosis”, reported Salut. “We have not yet received results from the Carlos III Health Institute”, where the patient’s samples were sent to confirm the diagnosis.
80% of West Nile virus infections are asymptomatic, so they go undetected. The other 20% cause the so-called West Nile fever, which is characterized by an abrupt onset of symptoms. Symptoms may include high fever, headache, muscle pain, eye pain, skin rashes and vomiting.
In the most serious cases, the virus infects the nervous system and can be fatal or leave serious sequelae. This happens in one out of every hundred infections (or one out of twenty cases with fever).
Given the evidence that the West Nile virus is already endemic in Catalonia, and the strong suspicion that the woman admitted to Bellvitge contracted it, screening for the virus has begun in all donations. The measure was already applied last year, when the first two cases were detected in Reus, but that time the screening was limited to three counties.
In addition, an investigation has been carried out on the mosquitoes present in the area where the patient lives and a treatment with larvicides has been applied.
Residents of the area have received informative leaflets by mail on the measures they can take to prevent the proliferation of mosquitoes, which is considered the most effective prevention strategy. The main recommendation is to prevent mosquitoes from finding stagnant water as a breeding ground.
