The Chikungunya virus: An emerging US pathogen

BACKGROUND:The Chikungunya(CHIK)virus was recently reported by the CDC to have spread to the United States.We report an early documented case of CHIK from the state of Pennsylvania after a patient recently returned from Haiti in June of 2014.METHODS:A 39-year-old man presented to the emergency department complaining of fever,fatigue,polyarthralgias and a diffuse rash for two days.Four days before,he returned from a mission trip to Haiti and reported that four of his accompanying friends had also become ill.A CHIK antibody titer was obtained and it was found to be positive.During his hospital stay,he responded well to supportive care,including anti-inflammatories,intravenous hydration and anti-emetics.RESULTS:His condition improved within two days and he was ultimately discharged home.CONCLUSIONS:Manifestations of CHIK can be similar to Dengue fever,which is transmitted by the same species of mosquito,and occasionally as a co-infection.Clinicians should include Chikungunya virus in their differential diagnosis of patients who present with fever,polyarthralgia and rash with a recent history of travel to endemic areas,including those within the United States.

Introduction of invasive mosquito species into Europe and prospects for arbovirus transmission and vector control in an era of globalization

Background Mosquito research in Europe has a long history,primarily focused on malaria vectors.In recent years,invasive mosquito species like the Asian tiger mosquito(Aedes albopictus)and the spread of arboviruses like dengue virus,chikungunya virus or bluetongue virus have led to an intensifcation of research and monitoring in Europe.The risk of further dissemination of exotic species and mosquito-borne pathogens is expected to increase with ongoing globalization,human mobility,transport geography,and climate warming.Researchers have conducted various studies to understand the ecology,biology,and efective control strategies of mosquitoes and associated pathogens.Main body Three invasive mosquito species are established in Europe:Asian tiger mosquito(Aedes albopictus),Japanese bush mosquito(Ae.japonicus),and Korean bush mosquito(Aedes koreicus).Ae.albopictus is the most invasive species and has been established in Europe since 1990.Over the past two decades,there has been an increasing number of outbreaks of infections by mosquito-borne viruses in particular chikungunya virus,dengue virus or Zika virus in Europe primary driven by Ae.albopictus.At the same time,climate change with rising temperatures results in increasing threat of invasive mosquito-borne viruses,in particular Usutu virus and West Nile virus transmitted by native Culex mosquito species.Efective mosquito control programs require a high level of community participation,going along with comprehensive information campaigns,to ensure source reduction and successful control.Control strategies for container breeding mosquitoes like Ae.albopictus or Culex species involve community participation,door-to-door control activities in private areas.Further measures can involve integration of sterile insect techniques,applying indigenous copepods,Wolbachia sp.bacteria,or genetically modifed mosquitoes,which is very unlike to be practiced as standard method in the near future.Conclusions Climate change and globalization resulting in the increased establishment of invasive mosquitoes in particular of the Asian tiger mosquito Ae.albopictus in Europe within the last 30 years and increasing outbreaks of infections by mosquito-borne viruses warrants intensifcation of research and monitoring.Further,efective future mosquito control programs require increase in intense community and private participation,applying physical,chemical,biological,and genetical control activities.

Long-distance spread of Tembusu virus,and its dispersal in local mosquitoes and domestic poultry in Chongming Island,China

Background Chongming Island in China serves as a breeding and shelter point on the East Asian–Australasian Flyway.The resting frequency of migratory birds,abundance of mosquito populations,and the popular domestic poultry industry pose a potential risk of mosquito-borne zoonotic diseases.The aim of this study is to explore the role of migratory birds in the spread of mosquito-borne pathogens and their prevalent status on the island.Methods We conducted a mosquito-borne pathogen surveillance in 2021,in Chongming,Shanghai,China.Approxi‑mately 67,800 adult mosquitoes belonging to ten species were collected to investigate the presence of faviviruses,alphaviruses,and orthobunyaviruses by RT-PCR.Genetic and phylogenetic analyses were conducted to explore the virus genotype and potential nature source.Serological survey was performed by ELISA to characterize Tembusu virus(TMUV)infection among domestic poultry.Results Two strains of TMUV and Chaoyang virus(CHAOV)and 47 strains of Quang Binh virus(QBV)were detected in 412 mosquito pools,with the infection rate of 0.16,0.16,and 3.92 per 1000 Culex tritaeniorhynchus,respectively.Fur‑thermore,TMUVs viral RNA was found in serum samples of domestic chickens and faecal samples of migratory birds.Antibodies against TMUV were detected in domestic avian serum samples,generally ranging from 44.07%in pigeons to 55.71%in ducks.Phylogenetic analyses indicated that the TMUV detected in Chongming belonged to Cluster 3,Southeast Asia origin,and most closely related to the CTLN strain,which caused a TMUV outbreak in chickens in Guangdong Province in 2020,but distant from strains obtained previously in Shanghai,which were involved in the 2010 TMUV outbreak in China.Conclusions We speculate that the TMUV was imported to Chongming Island through long-distance spreading by migratory birds from Southeast Asia,followed by spill over and transmission in mosquitoes and domestic avian species,threatening the local domestic poultry.In addition,the expansion and prevalence of insect-specifc favivi‑ruses and its simultaneous circulation with mosquito-borne virus are worthy of close attention and further study.

Pigsties near dwellings as a potential risk factor for the prevalence of Japanese encephalitis virus in adult in Shanxi,China

Background:The increasing trend of adult cases of Japanese encephalitis(JE)in China,particularly in northern China,has become an important public health issue.We conducted an epidemiological investigation in the south of Shanxi Province to examine the relationships between mosquitoes,Japanese encephalitis virus(JEV),and adult JE cases.Methods:Mosquito specimens were collected from the courtyards of farmers’households and pig farms in Shanxi Province.Mosquitoes were pooled,homogenized,and centrifuged.Reverse transcription-polymerase chain reaction(RT-PCR)was used to detect mosquito-borne arbovirus genes in homogenates.Specimens positive for these genes were inoculated into the baby hamster kidney cell line(BHK-21)to isolate virus.Minimum infection rate was calculated and phylogenetic analyses were performed.Results:A total of 7943 mosquitoes belonging to six species in four genera were collected;Culex tritaeniorhynchus accounted for 73.08%(5805/7943),C.pipiens pallens for 24.75%(1966/7943),and the remaining 3%(104/7943)consisted of Anopheles sinensis,Aedes vexans,Ae.dorsalis,and Armigeres subalbatus.Sixteen pools were positive for JEV based on RT-PCR using JEV pre-membrane gene nested primers.Phylogenetic analyses showed that all JEVs belonged to genotype I;two pools were positive using Getah Virus(GETV)gene primers.In addition,one JEV strain(SXYC1523)was isolated from C.pipiens pallens specimens.These results indicate that the minimum infection rate of JEV in mosquito specimens collected from the courtyards of farmers’households with pigsties was 7.39/1000;the rate for pig farms was 2.68/1000;and the rate for farmers’courtyards without pigsties was zero.Conclusions:The high-prevalence regions of adult JE investigated in this study are still the natural epidemic focus of JEV.Having pigsties near dwellings is a potential risk factor contributing to the prevalence of adult JE.To prevent the occurrence of local adult JE cases,a recommendation was raised that,besides continuing to implement the Expanded Program on Immunization for children,the government should urge local farmers to cease raising pigs in their own courtyards to reduce the probability of infection with JEV.

欧洲大陆蚊传虫媒病毒及相关疾病

从20世纪开始,已经证实有10种蚊传虫媒病毒在欧洲存在并流行,这些病毒在欧洲广泛分布,可以引起人类和牲畜的疾病,给欧洲各流行国家带来了巨大的疾病负担和经济损失。我国与欧洲大陆毗邻,有利于媒介昆虫的输入,有可能增加欧洲虫媒病毒传入我国的机会。本综述对欧洲流行的蚊传虫媒病毒及相关疾病进行概述,旨在为我国虫媒病毒性疾病的预防和控制工作提供依据。