A fourth case of West Nile fever has been confirmed in Bulgaria, with the latest diagnosis reported in a patient from Sofia, according to Prof. Iva Hristova, director of the National Center for Infectious and Parasitic Diseases (NCCPD). This follows the deaths of two patients due to complications from the illness and the ongoing treatment of a man in Haskovo.

Prof. Hristova indicated that there appears to be no direct link between the individual cases. She anticipates that more positive samples may be confirmed as testing continues. While she reassured that there is no immediate cause for alarm, she advised increased caution and adherence to preventive measures.

Recommendations include avoiding outdoor activities at night when mosquito activity is high and staying away from wooded areas where mosquitoes are more prevalent. Additionally, the Ministry of Health has issued a directive for mosquito spraying to help manage the situation.

Prof. Hristova noted that, statistically, one infected mosquito exists for every hundreds of thousands of mosquitoes. Approximately 80% of those infected with West Nile virus exhibit no symptoms, while 19% experience mild symptoms. These symptoms resemble those of a viral infection, including high fever, muscle pain, fatigue, and sometimes a mild rash.

Research indicates that in some regions, such as Sofia and areas along the Danube including Vidin, Ruse, and Silistra, 7-10% of residents might have had West Nile fever, possibly without realizing it. On a national level, around 1.5% of the population has been exposed to the virus over the past two to three years.

People over 70 years old and those with significant chronic conditions are at a higher risk of severe outcomes from West Nile fever, according to Prof. Hristova.