Western Nile Fever Virus Studied by Yerevan State Medical University 40 Years Ago: Armen Muradyan

Yerevan State Medical University (YSMU) began its research on the Western Nile fever virus 40 years ago (1985-1999), as stated by the rector of the Medical University, Armen Muradyan on his Facebook page.

“What is Western Nile fever? Western Nile fever belongs to the family of arboviruses. It was first discovered in the Western Nile region, from which it got its name. Arboviruses are transmitted by living vectors, mainly ticks and mosquitoes. There are over 500 species of arboviruses, more than 100 of which are pathogenic to humans,” said Hasmik Hovhannisyan, a professor at the Department of Epidemiology at YSMU.

Scientific research in Armenia was conducted by the Epidemiology Department from 1985 to 1999. These studies included epidemiological, entomological, insectological, virological, and serological investigations. “Every year, in the autumn and spring (during the peak of the disease), we have visited 10 regions of Armenia with our entomologist; we collected mosquitoes and ticks from 118 settlements, the results of which have been preserved. Then, virological studies were conducted on newborn mice that were only 1 to 2 days old; these mice are highly sensitive to arboviruses,” noted Hovhannisyan.

What characterizes arboviruses? Transmission of arboviruses worldwide occurs mainly through birds and rodents. Infected birds spread the virus, and when a tick or mosquito bites them, it becomes infected and can then transmit it to the human population. Arboviruses exhibit pronounced seasonality. Some pathogens can manifest very mildly with flu-like symptoms, while severe forms are also possible.

“In 8 out of 10 regions of Armenia, various arboviral strains have been isolated. The largest prevalence is found in Aragatsotn, Armavir, and Ararat regions, where mosquitoes are the vectors, while in Kotayk region, ticks are the vectors. We did not detect pathogens in Lori and Shirak regions. For the first time in Armenia, we isolated 22 strains of the Western Nile fever virus from mosquitoes and only 4 strains from ticks. Therefore, we emphasize primarily on mosquitoes,” Hovhannisyan emphasized.

According to her, the natural foci of transmittable viral infection can exist for a long time without causing concern, but recently, due to climatic changes, increasing temperatures, and large migrations of non-migratory birds, the situation has changed. According to WHO data, this disease mostly develops asymptomatically but can also lead to severe complications, including fatalities. Western Nile fever is listed among the WHO's specially dangerous infections.

The infection is transmitted to humans from living vectors—ticks and mosquitoes; there is no human-to-human transmission. However, it is essential to maintain vigilance and utilize research data. Currently, there is neither a specific treatment nor a vaccine available,” he wrote.