BackgroundAn outbreak of dengue virus (DENV) occurred in Yunnan province. More than 2,000 individuals were infected from August to November 2013. In this study, we aimed to characterize the origin and prevalence of DENV in Dehong prefecture of Yunnan province using phylogenetic and evolutionary analyses of DENV strains collected from local patients and foreign travelers.MethodsA total of 41 DENV-positive serum samples were randomly collected from travelers who entered China at Ruili port or local patients with dengue fever in Dehong prefecture of Yunnan province, China. The envelope (E) gene of DENV was amplified and sequenced. The distributions and evolutionary characteristics of different genotypes were elucidated by phylogenetic and Bayesian analyses.ResultsPhylogenetically, all of the 41 DENV-positive samples could be classified into genotype I (43.9%) of serotype DENV-1 and the Asian I genotype (56.1%) of serotype DENV-2. DENV strains derived from local patients and foreign travelers were scattered equally within these two clusters. Furthermore, the DENV strains from the two populations exhibited high relatedness based on evolutionary characteristics.ConclusionsThese results suggested that imported and local DENV strains occurring during the dengue outbreak in 2013 were highly related. Additionally, these data may suggest that this dengue outbreak was caused by a newly imported infection from the neighboring country of Myanmar.

BackgroundYunnan is not only considered the region with the most concerning human immunodeficiency virus (HIV)-1 prevalence, but is also the central hub for the spread of HIV-1 from Southeast Asia to the other provinces of China. Yunnan has the highest proportion of entry travelers who have transmitted HIV from neighbored Southeast Asian countries to mainland of China.MethodsBetween 2003 and 2012, we recruited 280,961 entry travelers at land ports located in 7 bordering prefectures respectively in the Yunnan Province for HIV-1 screening. Based on the detection of HIV-1 antibody, the HIV-1 infection rate was determined.ResultsAmong the recruited entry travelers, 2380 were determined HIV-1 positive with infection rate of 0.85%. Travelers entering the Dehong port had the highest HIV-1 infection rate (5.12%), followed by those entering Baoshan (0.88%), Lincang (0.83%), and Honghe (0.71%). For all HIV-1 positive cases, travelers aged 21–30 and 31–40 were the most commonly infected individuals, accounting for 38.45% and 37.77% of all cases, respectively. The most common occupation of the infected population was driver (42.38%), and the proportion of industrials had increased yearly. Based on the reported risk factors, sexual transmission was the main HIV-1 infection route (77.11%) of this population.ConclusionsWe have clarified the rate of HIV-1 infection among this bridge population. The characteristics of HIV-1 positive population and high geographical heterogeneity have provided the necessary epidemiological data for monitoring the HIV-1 epidemic among cross-border travelers in Yunnan and to further understand the cross-border spreading of the HIV-1 infection.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-015-1683-8) contains supplementary material, which is available to authorized users.

BackgroundThe China-Myanmar border is a particularly interesting region that has very high prevalence of and considerable diversity of HIV-1 recombinants. Due to the transient nature of their work, long-distance truck drivers (LDTDs) have a comparatively high potential to become infected with HIV-1 and further spread virus to other individuals in the area they travel within. In this study, we hypothesized that Burmese LDTDs crossing the China-Myanmar border frequently may potentially be involved in the cross-border transmission of HIV, and contribute to the extremely high prevalence of HIV-1 inter-subtype recombinants in this border region.MethodsA molecular epidemiology study was conducted among 105 Burmese LDTDs between 2008 and 2010. HIV-1 genetic fragments including p17, pol, vif-vpr, vpr-env, and C2V3 were amplified and sequenced. The subtype characterization and HIV-1 transmission were determined by both phylogenetic and phylogeographic analyses.ResultsDiverse forms of HIV-1, including subtypes CRF01_AE (41.9%), C (8.6%), B (4.8%), CRF02_AG (1.0%), and inter-subtype recombinants (33.3%), as well as dual infection (10.5%), were detected among the tested LDTDs. Phylogeographic analyses based on pure subtype revealed that 77.8% Burmese LDTDs acquired HIV-1 infection in Yunnan, and the others in Myanmar. Both the C-related and CRF01_AE-related recombinants from these LDTDs appeared to have close genetic relationship with those from IDUs in Myanmar and Dehong.ConclusionsBurmese LDTDs may contribute to HIV-1 transmission along the China-Myanmar border. The results may provide some new perspective for understanding the on-going generation and prevalence of HIV-1 recombinants in the border region.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2334-14-463) contains supplementary material, which is available to authorized users.

Association between vitamin D receptor (VDR) BsmI (rs1544410) gene polymorphism and the risk of type 1 diabetes mellitus (T1DM) from the published reports are still conflicting. This study was conducted to evaluate the relationship between VDR BsmI gene polymorphism and the risk of T1DM using meta-analysis method. The association studies were identified from PubMed, and Cochrane Library on 1 December 2013, and eligible investigations were included and synthesized using meta-analysis method. Twenty-three reports were recruited into this meta-analysis for the association of VDR BsmI gene polymorphism with T1DM susceptibility. In overall populations, bb genotype was associated with T1DM, but the B allele and BB genotype were not. In Asians and Latino population, B allele and bb genotype were associated with TIDM risk, but BB genotype was not. In Caucasians, VDR BsmI gene polymorphism was not associated with the T1DM risk. In Africans, B allele and BB genotype were associated with T1DM risk, but the bb genotype was not. However, the sample size for Latino population and Africans was small. In conclusion, VDR BsmI B allele, bb genotype was associated with T1DM risk in Asians, and bb genotype was associated with T1DM risk in overall populations. However, more studies should be conducted to confirm it.

BackgroundThe overall success of Human immunodeficiency virus type 1 (HIV-1) antiretroviral therapy (ART) was heavily challenged upon the occurrence of drug resistance. Dehong Prefecture witnessed not only the first report of HIV-1 infection but also the experimental adoption of antiviral treatment in China. The transmission and epidemic of HIV-1 in Dehong is impacted by cross-border activities. The characteristics of HIV-1 drug resistance among therapy-naïve Burmese entering travelers in Yunnan and their speculated origin are still not clarified.MethodsTwo hundred ninety-eight HIV-1 infected Burmese entering travelers at Dehong ports were recruited between 2003 and 2012. The partial HIV-1 pol gene fragments were amplified and sequenced for the analysis of drug-resistance mutations (DRMs). Phylogenetic analysis on gag-pol gene was conducted to elucidate phylogenetic and evolutionary characteristics of these drug resistant strains.ResultsIt was figured out that the occurrence ratio of HIV-1 drug resistance among HIV-1 infected entering travelers from Myanmar was up to 12.8%. The resistant mutations covered several types, including one type of PI mutations (L33F), six types of NRTI mutations and seven types of NNRTI. Close genetic relationship was observed in the phylogenetic analysis on gag-pol gene among the drug resistant strains respectively from Dehong, other Yunnan areas, neighboring provinces (Guangxi) and neighboring countries (Thailand and Myanmar).ConclusionsThe findings in this study revealed that HIV drug resistant locus is spreading from the population who is receiving drug-resistance treatment to the new infectors, which indicates the urgency of surveillance work on drug resistance among the migrant population with high risks of HIV infection.Electronic supplementary materialThe online version of this article (10.1186/s12879-018-3130-9) contains supplementary material, which is available to authorized users.