Ispitivanje infekcije Virusom Zapadnog Nila kod ljudi i komaraca u Južnobačkom okrugu

Abstract

West Nile virus (WNV) is arbovirus distributed throughout the world. It belongs to the Flaviviridae family, serocomplex Japanese encephalitis and maintained in transmission cycle between wild birds and ornithophilic mosquitoes. In humans, 80% of cases are asymptomatic. In 20% of infected people, clinical manifestations present with febrile illness. In 1% of cases infection may result in neuroinvasive diseases with permanent neurological consequences or lethal outcome. Serological studies conducted in South Backa district indicated that the WNV circulates among humans. First detection of WNV genome in territory of South Backa district was in 2010 in Culex pipiens mosquitoes collected in Novi Sad. Since 2013, WNV infections of humans are diagnosed every year from June to November in Institute of Public Health of Vojvodina (IPHV). Since the period of 2013 - 2016, 477 pools of mosquitoes, collected in different location of South Backa district, are examined by real time PCR (Real-TM Sacace biotechnologies Italy) in IPHV. In total, 316 persons suspected on WNV infection were tested by ELISA IgG and IgM (Euroimmun, Germany). Also, 128 samples of cerebrospinal fluid or/and serum of people suspected on WNV infection were examined by commercial molecular tests. WNV genome was detected in 29/477 (6%) examined pools of mosquitoes (2013- not tested; 2014- 7/169 (4.1%); 2015- 16/214 (7.5%); 2016- 6/94 (6.4%). Over the period of 2013 - 2016, 50 confirmed cases of WNV infection were diagnosed in humans: 2013 - 21/80 (26%), 2014- 12/146 (8.2%), 2015- 10/59 (16.9%), 2016- 7/31 (22.6%). IgM antibodies were detected in cerebrospinal fluid in 30/50 (60%) patients with confirmed WNV infection. The presence of IgM antibodies was confirmed in serum in 37/50 (74%). Seroconversion was proven in second serum sample in 11/50 (22%), while WNV genome was detected in cerebrospinal fluid or/and serum in 7/50(14%). According to results obtained by this study, WNV is a significant pathogen in South Backa district.