Detection of West Nile virus genome and specific antibodies in Iranian encephalitis patients

Abstract

West Nile virus (WNV) is a mosquito-borne flavivirus which circulates in birds, horses and humans. An estimated 80% of WNV infections are asymptomatic. Fewer than 1% of infected persons develop neuroinvasive disease, which typically presents as encephalitis, meningitis, or acute flaccid paralysis. This study was conducted from January 2008 to June 2009 in Isfahan, Iran. Patients attending the emergency department with fever and loss of consciousness were consecutively included. Cerebrospinal fluids (CSF) were initially analysed through bacteriology and biochemistry examinations, resulting in those with evidence of meningitis being excluded. Patients' CSF and serum were diagnosed by serological and molecular assays. A total of 632 patients with fever and loss of consciousness were tested by CSF analyses. Samples of the remaining patients (39·4%) were referred for WNV investigation. Three (1·2%) of the patients were positive for both serum and CSF by RT-PCR, and six (2·4%) were positive only for IgG antibodies. History of insect bite, and blood transfusion and transplantation were risk factors for being positive by RT-PCR (P=0·048) and being IgG positive (P=0·024), respectively. The results of this study showed that the prevalence of West Nile fever is low in patients with encephalitis.

Phylogenetic Analysis of West Nile Virus Genome, Iran

“…Test samples and peroxidase-labeled anti-human or anti-animal immunoglobulin were added. After incubation for 10 min, optical densities were read ( 6 ). …”

“…A reverse transcription PCR was conducted by using a One-Step RT-PCR Kit (QIAGEN). Samples were subjected to 1 cycle at 50°C for 30 min to synthesize cDNA; 95°C for 15 min; and 95°C for 30 s, 54°C for 30 s, and 72°C for 60 s; and a final extension at 72°C for 5 min ( 6 ). The serum sample was positive for IgG against WNV.…”

Seroprevalence of West Nile Virus in Iran

“…Although, 75% of infected human cases had animal contacts, these data did not suggest that human infections These data are complementary with the circulation of WNV among the population in Isfahan Province, since our previous study on encephalitis patients in Isfahan Province showed that 1.2% of them were positive for both serum and CSF RT-PCR, and 2.4% were positive only for IgG antibody (Chinikar et al 2012).…”

“…In addition, a more recent study on healthy human blood donors in 2005 showed that 5% of donors were IgG positive to WNV (Talebian 2010). In our previous study between 2008 and 2009, we demonstrated that 3.6% of patients with encephalitis symptoms had been infected by WNV (Chinikar et al 2012).…”

Genetic variants associated with susceptibility of Ashkenazi Jews to West Nile virus infection

“…Regionally, several reports from the Middle East have shown that the seroprevalence of WNV ranged from 1·3% to 26% of the populations [24][25][26][27][28][29][30][31]. However, an outbreak of WNV neuroinvasive disease has been reported only in Israel.…”