Prisustvo Usutu virusa u komarcima na podruèju Vojvodine u 2017 godini

Abstract

In the past few years, the presence and significant distribution of the West Nile virus (WNV) has been identified in the territory of Serbia. This virus has caused epidemics in humans starting from 2012 until today. Usutu virus (USUV), which is in all of its characteristics (morphological, antigenic, and genetic) very similar to WNV belongs to the same genus, Flavivirus. Another similarity is that USUV, as well as WNV, is maintained in nature in a transmissible cycle between birds as natural hosts and mosquitoes, most commonly of Culex genus as a virus vectors. Mammals, such as a humans, horses, and some other mammals, as in the case of WNV infection, are random hosts that may be infected with or without a clinical picture of encephalitis / meningoencephalitis. The virus was detected for the first time in South Africa in 1959, and the first human case in Europe was detected in Italy in 2009. Recent studies indicate the presence and e of USUV in the surrounding countries, Italy, Austria, as well as in Croatia where the first human clinical case has been recently confirmed. The goal of this pilot study was to test the presence, distribution and prevalence of USUV in mosquito vectors in the area of Vojvodina and to evaluate the possible risk to human and animal health. In total, 109 pools (50 individuals in a pool) of Culex pipiens mosquitoes were tested, 43 of which were sampled in July and 66 in August 2017 on the territory of Vojvodina Province. Out of that number, 19 samples were taken from the area of the North Bačka District, 17 of them were from Western Bačka District, 16 from South Bačka, 17 from Srem, 18 from South Banat, 17 from Central Banat and 5 from North Banat District. The presence of USUV was tested by a molecular real-time RT-PCR method highly specific to USUV without cross-reaction with other flaviviruses, such as WNV. Three out of 109 tested samples (3/109; 2.75%) were determined positive on the presence of USUV. The USUV was found in Culex pipiens mosquitoes sampled in July in town Bačka Topola (Nort Bačka District), and in mosquitoes sampled in August in the settlement Sefkerin (South Banat District) and in town Odžaci (Western Bačka District). The obtained results confirmed the presence of USUV in vectors in the territory of Serbia – Vojvodina Province in 2017, as well as the previous findings of this virus in mosquitoes and of specific antibodies in human’s blood sera in South Bačka District in 2015, by the same authors. All the findings indicate that in addition to WNV and recently detected Tick-borne encephalitis virus, one more flavivirus circulates in Serbia. Finding is likewise very important from the aspect of differential diagnosis in clinical cases of encephalitis and meningoencephalitis, which can definitely be also the result of USUV infection.