ABSTRACT
INTRODUCTION: Current published reports on the causative agents of acute febrile illness (AFI) in Afghanistan are scarce, and the burden of disease due to flaviviruses is unknown. METHODOLOGY: A hospital-based surveillance study for AFI was established in 2008 through 2010 to determine the seroepidemiology of West Nile virus (WNV), tick-borne encephalitis virus (TBEV) and dengue viruses (DENV) using commercial ELISA kits. Due to major logistical challenges, only acute sera were collected. RESULTS: Serological analysis for IgG were as follows: WNV 30.4% (277/913); TBEV 23.4% (214/913); DENV 19.7% (180/913). Single positive IgG reactions for WNV, TBEV and DENV were noted in 11% (100/913), 7.2% (66/913), and 5% (47/913), respectively. Reactivity for all three screened flaviviruses was detected in 44.5% (406/913) of sera. IgM positivity was uncommon, with only 0.5% (5/913), 2.2% (20/913) and 2.6% (8/312) of samples positive for WNV, TBEV, and DENV, respectively. Serological findings were confirmed in random positive samples by neutralization assay. CONCLUSIONS: These serological results suggest circulation of WNV, TBEV, and DENV within Afghanistan, with evidence of current or prior infection noted in a significant proportion of patients seeking care for AFI. Obtaining additional information on the prevalence of these and other causes of AFI is paramount for improving the distribution of available limited syndromic treatment and improving the existing health protection policy in Afghanistan.
Subject(s)
Dengue Virus/isolation & purification , Encephalitis Viruses, Tick-Borne/isolation & purification , Fever/epidemiology , Fever/etiology , Flavivirus Infections/epidemiology , West Nile virus/isolation & purification , Adult , Afghanistan/epidemiology , Antibodies, Viral/blood , Dengue Virus/immunology , Encephalitis Viruses, Tick-Borne/immunology , Female , Flavivirus Infections/diagnosis , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Prevalence , Serologic Tests , West Nile virus/immunology , Young AdultABSTRACT
Anopheles sinensis Wiedemann (63.3%) was the most abundant Anopheles mosquito captured at cowshed resting collections in malaria high-risk areas (northern Gyeonggi Province) near the demilitarized zone (DMZ) in Korea during 2005, followed by Anopheles kleini Rueda (24.7%) and Anopheles pullus M. Yamada (8.7%). At cowshed resting collections in malaria low-risk areas (Jeonnam and Gyeongnam provinces), An. sinensis accounted for 96.8% of all Anopheles spp. collected, followed by An. kleini Rueda (2.7%), whereas no An. pullus were collected. Three species, An. kleini (50.9%), An. pullus (29.0%), and An. sinensis (13.8%), accounted for nearly all of the 224 Anopheles spp. captured by New Jersey light trap near the DMZ. In addition, An. pullus and An. kleini captured by New Jersey light trap near the DMZ and assayed by enzyme linked immunosorbent assay for Plasmodium vivax circumsporozoite antigen concentrations were higher than An. sinensis sensu stricto (s.s.), indicating higher levels of sporozoites. In laboratory studies of four concurrent artificial membrane feedings on malaria-infected blood from patients, F1 progeny of An. kleini and An. pullus had higher infection rates (8.8 and 7.5%, respectively) than An. sinensis s.s. (4.2%). These data suggest that An. kleini and An. pullus and An. sinensis are vectors of malaria in Korea. Further studies are required to determine the role of these species in the transmission of P. vivax in the Republic of Korea.
