ABSTRACT
In 2014, Guangzhou City, South China, suffered from its worst outbreak of dengue fever in decades. Larval mosquito habitat surveillance was carried out by using android mobile devices in four study sites in May 2015. The habitats with larval mosquitoes were recorded as photo waypoints in OruxMaps or in videos. The total number of potential mosquito habitats was 342, of which 166 (49%) were found to have mosquito larvae or pupae. Small containers were the most abundant potential habitats, accounting for 26% of the total number. More mosquito larvae and pupae, were found in small containers than in other objects holding water, for example, potted or hydroponic plants (p < 0.05). Mosquito larvae were collected from all plastic road barriers, used tires, and underground water. Aedes albopictus larvae were found from small and large containers, stumps, among others. The overall route index (RI) was 11.3, which was 14.2 times higher than the grade C criteria of the National Patriotic Health Campaign Committee (NPHCC), China. The higher RIs were found from the bird and flower markets, schools, and underground parking lots. The results indicated that Android mobile devices are a convenient and useful tool for surveillance of mosquito habitats, and the enhancement of source reduction may benefit the prevention and control of dengue vector mosquitoes.
ABSTRACT
Hemorrhagic fever with renal syndrome (HFRS) has been a significant public problem since the first cases were reported in 1961 in Wuhan city (capital of Hubei province of China). Epidemiological surveys were carried out to better understand the dynamics of hantavirus infection in humans and animals in Wuhan. During 1961-2011, a total of 21,820 HFRS cases were registered in Wuhan. The two large epidemics had occurred during 1970-1991. They reached peaks in 1973 and 1983, respectively. There have been <10 cases since 2005. The disease occurred in the whole region including the downtown areas, but mainly in two districts. Although in 1980s and 1990s HFRS cases mainly recorded in August and winter, since 2000 the disease has mainly occurred in spring and summer. In this study, hantaviruses were identified in Apodemus mice, Rattus rats, and Mus mice by indirect immunofluorescent-assay and RT-PCR. Serological and genetic analyses showed that Hantaan virus (HTNV) and Seoul virus (SEOV) co-circulated in rodents. Phylogenetic analysis of hantaviral genome sequences revealed a novel genetic lineage of HTNV circulating in rodents in Wuhan. Another lineage of HTNV was closely related to the lineages from the provinces located in the origin and delta of Yangtze River. Remarkably, SEOV variants identified in Wuhan were more closely related to the variants found outside China. Results of the present study showed that HFRS cases in Wuhan are caused by HTNV and SEOV. Phylogenetic analysis of the hantavirus sequences revealed that a novel genetic lineage of HTNV is present in rodents in Wuhan.
Subject(s)
Hantaan virus/classification , Hemorrhagic Fever with Renal Syndrome/epidemiology , Hemorrhagic Fever with Renal Syndrome/virology , Seoul virus/classification , Animals , Antibodies, Viral/blood , China/epidemiology , Epidemics , Genes, Viral/genetics , Hantaan virus/genetics , Hantaan virus/isolation & purification , Humans , Mice , Phylogeny , Prevalence , RNA, Viral/analysis , RNA, Viral/chemistry , Rats , Seasons , Seoul virus/genetics , Seoul virus/isolation & purificationABSTRACT
OBJECTIVE: To analyze the molecular characteristics of the newly isolated two Japanese encephalitis virus strains (JEV) in Wuhan. METHODS: The mosquitoes were collected in Wuhan from April to October in 2009. The envelope (E) protein gene of JEV was detected using RT-PCR and sequenced. Sequence comparisons and phylogenetic analysis were conducted using DNAstar and MegAlign. RESULTS: Two Japanese encephalitis virus (JEV) strains (WHJX09-9, WHJX09-10) were isolated from Culex tritaeniorhynchus among 16 mosquito pools and identified as genotype I. The result showed that the homology of the two strains was 98. 9% in nucleotides and 100% in deduced amines. The comparison between the new genotype 1 JEV strains and live attenuated vaccine strain SA14-14-2 in E gene showed that the homology of nucleotide sequence was 87.4% and 87.9%, the homology of amino acid was 96.9% (total 15 amino acid were different) in E gene. The mutation sites of amino acid distributed among three different coding domain, but no antigen binding site and neurotoxin-involved site of amino acid were changed. CONCLUSION: Wuhan had appeared a new genotype of JEV which was different from the former strain isolated in Wuhan, the new JEV strains still had neurotoxicity but had high homology with the vaccine strains adopted in Wuhan. The vaccine could still be adopted to prevent Japanese encephalitis if steps were take to eradicate mosquitos at the same time. laboratory surveillance were also an important task to build an early-warning mechanism against JEV.
