ABSTRACT
Influenza B virus-caused illness has recently been considered as an urgent public health problem due to substantial morbidity, mortality and life-threatening medical complications. In this study, we have reported the main characteristics of influenza B virus in Mongolia, including prevalence, lineages, suitability with vaccine strains and drug susceptibility against the virus. 15768 specimens were tested by qPCR for detecting influenza viruses. From positive specimens for influenza B virus, the clinical isolates were isolated using MDCK cells. Sequencing analysis, hemagglutination inhibition assay and Neuraminidase inhibitor (NAI) drug susceptibility testing were performed for the clinical isolates. Influenza B virus was around in 3.46% of the samples in Mongolia, and B/Victoria clade-1A and B/Yamagata clade-3 lineages were predominant. Importantly, it was confirmed that the lineages corresponded to the vaccine strains. Moreover, drug susceptibility tests revealed that some Mongolian clinical isolates showed reduced susceptibility to antiviral agents. Interestingly, G104R was identified as a novel mutation, which might have a significant role in drug resistance of the virus. These results describe the characteristics of influenza B viruses that have caused respiratory illness in the population of Mongolia between 2013 and 2017.
Subject(s)
Influenza B virus/isolation & purification , Influenza, Human/diagnosis , Animals , Antiviral Agents/pharmacology , Dogs , Drug Resistance, Viral/drug effects , Enzyme Inhibitors/pharmacology , Hemagglutination Inhibition Tests , Hemagglutinins/classification , Hemagglutinins/genetics , Humans , Influenza B virus/drug effects , Influenza B virus/genetics , Influenza, Human/epidemiology , Influenza, Human/virology , Madin Darby Canine Kidney Cells , Mongolia/epidemiology , Mutation , Neuraminidase/genetics , Phylogeny , Prevalence , RNA, Viral/chemistry , RNA, Viral/genetics , RNA, Viral/metabolism , Sequence Analysis, RNAABSTRACT
Hepatitis B virus infection is a serious public health problem. Mongolia is one of the countries with the highest rates of hepatitis B virus infection in the world. The routine immunization with the hepatitis B vaccine began nationwide in 1991. The purpose of this study was to determine the persistence of seroprotection (anti-HBs >or= 10 mlU/mL) in children 5-10 years old that were immunized with the hepatitis B vaccine as infants. In total, 438 children were selected from six health facilities in Ulaanbaatar through a multistage random sampling method. Vaccination information was confirmed by checking the vaccination records kept in the health facilities. A blood sample was obtained from each child for anti-HBs, HBsAg and anti-HBc. Of 438 children, five (1.1%) were HBsAg positive and 58 (13.2%) were anti-HBc positive. Sixty infected children were excluded and a total of 378 (86.3%) sera were evaluated. The seroprotective antibodies were detected in only one-fourth of the children at the age of ten. Titres of anti-HBs decreased significantly with age (Linear regression p = 0.01). This decrease is primarily due to the rapid decrease in children living in ger areas (p < 0.001) compared to children living in apartment areas (p = 0.152). On the other hand, children living with higher socio-economic status had more exposure to blood-borne pathogens, probably due to inappropriate health-seeking behaviors.