Malaga province West Nile virus patient leaves intensive care after his condition improves

He was admitted via the A&E a week before his case came to light. He was presenting with a fever and a headache. Following a series of tests, doctors determined that he was suffering from encephalopathy: a disorder affecting brain function that can manifest as confusion, drowsiness or changes in the level of consciousness.

The doctors initially thought it might be another condition, as encephalopathy is a condition that can be associated with various diseases. His biological samples were sent to Hospital Universitario Virgen de las Nieves in Granada, the centre of excellence in eastern Andalucía for this condition, which confirmed the infection.

All patients suspected of having West Nile virus are subject to a specific protocol, which includes the analysis of their biological fluids (cerebrospinal fluid, urine, blood), with samples sent to Granada for testing. The Virgen del Rocío hospital in Seville is responsible for this procedure in the western part of Andalucía.

Once the positive result had been confirmed, the Clínico hospital notified the public health department, which notified the regional ministry of health.

Consequently, the A&E and ICU departments at the Clínico worked in coordination to rule out the various conditions that could cause encephalopathy, including West Nile virus.

West Nile virus (WNV) is transmitted primarily through the bites of mosquitoes of the genus Culex. These mosquitoes get the virus when they bite infected birds and can subsequently transmit it to other birds, horses or people.

Humans may be either accidental or definitive hosts. The virus cannot be transmitted from person to person. The epidemiological problem therefore lies in the circulation of the virus among mosquitoes and birds.

In 80 per cent of cases, the person does not develop any symptoms, but in 20 per cent of cases they may develop West Nile fever, a headache, fatigue, muscle aches, nausea, vomiting or a skin rash. A small proportion of cases develop the severe form, namely neuroinvasive disease, which can cause meningitis, encephalitis, altered consciousness, seizures, muscle weakness or paralysis.

The risk of developing a serious illness increases if the person is elderly or has a weakened immune system.

In Malaga province, there were only four confirmed cases in 2024 and none throughout 2025. The province is an ideal environment for the transmission of the virus, although the majority of cases are asymptomatic or present only mild symptoms.

As president of the SEIMC (society of infectious diseases and clinical microbiology) Dr Francisco Javier Membrillo told Sur in May 2025, there are more cases of this tropical virus in Andalucía every year.

"We have to bear in mind that we are only seeing the tip of the iceberg, as most of the cases are asymptomatic or with mild symptoms, which means that probably only serious cases end up at hospitals, especially in Western Andalucía, although also increasingly in the north. Climate change, the increase in temperatures in recent years and spring rains this year mean that all the conditions are in place for it to be a summer with lots of mosquitoes, which is what will favour the transmission of the virus," he said.

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