RSDNet: A New Multiscale Rail Surface Defect Detection Model.

The rapid and accurate identification of rail surface defects is critical to the maintenance and operational safety of the rail. For the problems of large-scale differences in rail surface defects and many small-scale defects, this paper proposes a rail surface defect detection algorithm, RSDNet (Rail Surface Defect Detection Net), with YOLOv8n as the baseline model. Firstly, the CDConv (Cascade Dilated Convolution) module is designed to realize multi-scale convolution by cascading the cavity convolution with different cavity rates. The CDConv is embedded into the backbone network to gather earlier defect local characteristics and contextual data. Secondly, the feature fusion method of Head is optimized based on BiFPN (Bi-directional Feature Pyramids Network) to fuse more layers of feature information and improve the utilization of original information. Finally, the EMA (Efficient Multi-Scale Attention) attention module is introduced to enhance the network's attention to defect information. The experiments are conducted on the RSDDs dataset, and the experimental results show that the RSDNet algorithm achieves a mAP of 95.4% for rail surface defect detection, which is 4.6% higher than the original YOLOv8n. This study provides an effective technical means for rail surface defect detection that has certain engineering applications.

Analysis of a Sabin-Strain Inactivated Poliovirus Vaccine Response to a Circulating Type 2 Vaccine-Derived Poliovirus Event in Sichuan Province, China 2019-2021.

Importance: The Sabin-strain inactivated poliovirus vaccine (IPV) may be a tool for polio outbreak response in certain situations. Objective: To investigate the response to a type 2 vaccine-derived poliovirus (VDPV2) outbreak. Design, Setting, and Participants: This case series was conducted in China after a VDPV2 was detected in stool specimens from a child with acute flaccid paralysis (AFP) in Sichuan Province in 2019, 3 years after the global withdrawal of live, attenuated type 2 oral poliovirus vaccine (OPV). Investigation followed National Health Commission and World Health Organization guidance and included searching hospitals for unreported AFP cases; testing stool specimens from the child, his contacts, and local children; enhanced environmental surveillance for VDPV2s in wastewater; and measuring vaccination coverage. Sabin-strain IPV campaigns were conducted in a wide geographic area. Main Outcomes and Measures: Any VDPV2 detection after completion of the supplementary immunization activities. Results: A 28-nucleotide-change VDPV2 was isolated from a young boy. Three VDPV2s were detected in healthy children; 2 were contacts of the original child, and none had paralysis. A search of 31 million hospital records found 10 unreported AFP cases; none were polio. No type 2 polioviruses were found in wastewater. Prior to the event, polio vaccine coverage was 65% among children younger than 5 years. Sabin-strain IPV campaigns reached more than 97% of targeted children, administering 1.4 million doses. No transmission source was identified. More than 1 year of enhanced poliovirus environmental and AFP surveillance detected no additional VDPVs. Conclusions and Relevance: These findings suggest that the circulating VPDV2 outbreak in 2019 was associated with low vaccine coverage. An investigation discovered 3 infected but otherwise healthy children and no evidence of the virus in wastewater. Following Sabin-strain IPV-only campaigns expanding from county to prefecture, the poliovirus was not detected, and the outbreak response was considered by an expert panel and the World Health Organization to have been successful. This success suggests that the Sabin-strain IPV may be a useful tool for responding to circulating VDPV2 outbreaks when high-quality supplementary immunization activities can be conducted and carefully monitored in settings with good sanitation.

Sexual behaviors related to HIV infection in Yi women of childbearing age in rural areas of southwest China.

Liangshan Prefecture, the highest HIV-affected epidemic region in China, has more than 2.5 million Yi people. We firstly investigated the sexual behaviors and the related social determinants of health for HIV infection in Yi women of childbearing age in this area. A total of 800 Yi women of childbearing age were enrolled. Path analysis of the risk factors revealed that casual sex (0.152) and number of sex partners (0.152) were directly associated with HIV infection. Furthermore, education level (0.057), out-migrating for work (0.032), sense of self-worth (0.024) and number of sex partners (0.079) were indirectly related to HIV infection and mediated by casual sex and multiple sexual partners. The epidemic of HIV infection among Yi women of childbearing age in Liangshan Prefecture is serious, future promotion should increase their knowledge about condom and modify their perceptions of sexual behaviors.

The changing modes of human immunodeficiency virus transmission and spatial variations among women in a minority prefecture in southwest China: An exploratory study.

Liangshan Yi Autonomous Prefecture in Southwest China has a high human immunodeficiency virus (HIV) prevalence rate. This study examined the changing modes of HIV transmission among women with new HIV infections and explored the spatial heterogeneities in the factors associated with heterosexual transmission in this minority region.The data consisting of women with new HIV infections from 2011 to 2014 were collected from multiple sources. New infections were identified by BED capture enzyme immunoassay. The Bayesian hierarchical model was used to estimate the proportion of women with new HIV infections via heterosexual transmission across all townships in the Prefecture. A geographically weighted regression (GWR) model was utilized to investigate spatial variations in the sociodemographic characteristics associated with the changing modes of HIV transmission.An analytical sample of 927 women with new HIV infections was constructed and utilized to investigate the changing mode of HIV transmission. The rate of heterosexual transmission among women with new HIV infections in 2011 was below 20%. However, by 2014 this rate dramatically increased to nearly 80%. Among sociodemographic characteristics, GWR results revealed significant ethnic differences in heterosexual HIV transmission between Yi women and women in other ethnic groups, with Yi women demonstrating a lower risk of infection through heterosexual transmission. However, such ethnic differences were observed only in 30% of the townships in the Prefecture. Moreover, having a primary education decreased the odds of heterosexual transmission, which was observed in about 56% of the townships. Also, being involved in occupations other than agriculture or animal husbandry and being single or married decreased the odds of HIV infection through heterosexual contact among women, which did not significantly vary across the Prefecture.Heterosexual transmission was the predominant mode of HIV transmission among women in the Prefecture, and this transformation was clearly marked by a fast-growing trend and a spatial diffusion pattern. Spatial variations also existed in sociodemographic factors that were associated with the changing modes of HIV transmission.

Detection and Initial Response to a Type 2 Vaccine-Derived Poliovirus - Sichuan Province, China, 2019.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: After the type 2 strain of the live, attenuated poliovirus vaccine was withdrawn globally in 2016, any identification of a type 2 poliovirus is a Public Health Emergency of International Concern. A vaccine-derived type 2 poliovirus (VDPV2) was identified in Sichuan, prompting an urgent, comprehensive investigation and response. WHAT IS ADDED BY THIS REPORT?: Type 2 monovalent, live, attenuated oral poliovirus vaccine (mOPV2) is being used to respond to the numerous VDPV2 outbreaks seen around the world. In contrast, the response in Sichuan used Sabin strain inactivated poliovirus (sIPV) to stop circulation of the VDPV2. In the 6 months following the vaccination response, there have been no VDPV2s detected in Sichuan, despite extensive search. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICES?: Further search for the VDPV2 must continue in order to determine whether transmission has been stopped. The ongoing investigation and response to the Sichuan VDPV2 is providing evidence to the Global Polio Eradication Initiative on managing VDPV2 outbreaks.

What factors hinder ethnic minority women in rural China from getting antenatal care? A retrospective data analysis.

BACKGROUND: Mother-to-child transmission (MTCT) is one of the main transmission routes of HIV, and the probability of MTCT can be dramatically reduced with comprehensive interventions. In southwest and western regions in China, the level of development in rural areas is relatively backwards and retains some original features, which also increases the difficulty of controlling infectious diseases. The Liangshan Prefecture started the prevention of MTCT programme in 2009. However, the implementation of the programme is not ideal, and the coverage of HIV testing is still low. Many Yi (local major ethnicity) women did not take antenatal care (ANC) and just gave birth to their babies at home for a variety of reasons. METHODS: Women with pregnancy history in the last 5 years were recruited from two townships based on cluster sampling. Face-to-face interviews were conducted to collect data. Descriptive analysis was performed to describe demographic characteristics, history of pregnancy and ANC uptake, knowledge of and attitudes towards ANC. Multivariable analysis was used to identify factors associated with uptake of ANC. RESULTS: Among 538 women who completed the questionnaires, 77.9% knew that ANC was necessary during and after pregnancy. However, only 24.2% actually accessed ANC. Almost all women (94.6%) expressed their willingness to receive ANC for pregnancy but barriers towards actual uptake of ANC existed including shyness, lack of independence and unavoidable cost. Multivariate analysis showed that no experience of living outside of Zhaojue for more than 6 months, higher number of births, not knowing the necessity of ANC during pregnancy and not knowing the government's promotion policies for ANC were associated with lack of ANC uptake. CONCLUSION: Although ethnic minority women in rural Liangshan expressed strong intention to use ANC, actual uptake of ANC was low. Knowledge of ANC and HIV prevention for MTCT should be improved among this population, and efforts should be made to help them overcome barriers to accessing ANC.

Cancer epidemics and the cancer prevention and control strategies in the United States: a review study / 中华预防医学杂志

In the past two decades,the United States made an impressed progress in the prevention and control of cancer that the overall morbidity and mortality of cancer had shown a downward trend, while China had seen an opposite trend. Cancer, one of the major public health concerns in China, has imposed an enormous burden onthe society and individuals. Therefore,in order to scientifically formulate cancer prevention and control policies, it is essential to make a comprehensive understanding of the practical experience in the field of cancer prevention and control from the United States. This article reviews the relevant literature on cancer trends as well as the prevention and control strategies in the United States,depictsthe cancer epidemic situation in the United States in the past 30 years, and summarizes the influencing factors, strategies and intervention experiences that lead to the improvement of cancer epidemic. It highlights the policy support, surveillance and intervention adopted by the United States for the cancer prevention and control. This article is expected to provide some implications and reference for the cancer prevention and control in China.

Clan-involved approaches to increasing antenatal care use in a rural minority area of China: implementation research.

AIM: This study aimed to test a model which involved clans and health providers to increase antenatal care attendance in rural minority areas of China with high HIV prevalence. METHODS: Formative research was conducted to determine barriers and facilitators to antenatal care use. A strategy involving clans in addressing the barriers identified was developed. Implementation of the new strategy was done through three plan-do-study-act (PDSA) cycles, lasting four months each. RESULTS: Awareness and uptake of antenatal care increased significantly after the intervention. The proportion of post-partum women who used any antenatal care increased from 21.3% to 64.5% (p < 0.001), and the proportion who knew that antenatal care is necessary increased from 77.8% to 89.8% (p < 0.001). The proportion of pregnant women who attended antenatal care (p < 0.001) and the proportion of pregnant women who went for a first antenatal care visit in early pregnancy (p < 0.001) all showed increasing trends during the study period. CONCLUSION: Involving clans in antenatal care programmes in rural minority areas of China had an impact on antenatal care use. A quality improvement approach incorporating PDSA cycles can help local health authorities make context-specific, evidence-informed decisions to improve uptake of health services.

Risk factors for HIV infection among 15 to 25-year-old rural unmarried Yi adolescents in an ethnic minority region of China.

We aimed to analyze factors related to human immunodeficiency virus (HIV) infection among 15 to 25-year-old rural unmarried Yi adolescents in Liangshan Yi Autonomous Prefecture from 2011 to 2016, and to investigate the relationship among the HIV-related risk factors.Three sites (Butuo, Zhaojue, and Ganluo counties) with a Yi population were selected from 2011 to 2016 in Liangshan prefecture. We used questionnaires to investigate demographic and behavioral characteristics and performed HIV testing. Logistic regression analysis and multiple correspondence analysis (MCA) were used to analyze the data.A total of 6311 qualified rural unmarried Yi adolescents were involved in this study, with an HIV infection rate of 4.18% (264/6311). Logistic regression analysis indicated that males (OR = 1.56, 95% CI = 1.17-2.08), illiteracy (OR = 2.70, 95% CI = 1.79-4.08), primary school education or below (OR = 1.62, 95% CI = 1.12-2.36), history of out-migrating for work (OR = 1.58, 95% CI = 1.18-2.13), and injecting drug user (IDU) (OR = 6.42, 95% CI = 3.06-13.46) contributed to the risk of HIV infection. MCA revealed a strong interrelationship between the following risk factors and HIV infection: aged 23 to 25 years, IDU, history of out-migrating for work, and ever having sexual behaviors.HIV infection among 15 to 25-year-old rural unmarried Yi adolescents in Liangshan is a serious issue. MCA and logistic regression analysis can be used to assess the relationship between risk factors for HIV infection.

Factors associated with HIV infection among Yi minority residents in Liangshan Prefecture, Sichuan Province: A path analysis.

We aimed to evaluate HIV prevalence among residents of Liangshan Prefecture through HIV sentinel surveillance (HSS) data over the period from 2010 to 2016, and investigate risk factors for HIV infection in this population and interactions among them.Two sites (Dechang and Ningnan counties) with majority-Han populations, and 1 site (Butuo) with a majority-Yi population were selected. We used questionnaires to investigate residents' demographic and behavioral characteristics from 2010 to 2016, and performed HIV testing. Multivariate logistic regression and path analysis were undertaken to investigate the interactions and mediating effects among significant risk factors for HIV infection.A total of 5403 community residents in the Yi area and 10,897 community residents in the Han areas were enrolled. HIV prevalence in the Yi area was consistently high, ranging from 9.46% (63/666, 2011) to 2.88% (23/798, 2012) over the period from 2010 to 2016. HIV prevalence in the Han areas ranged from 0.15% (2/1333, 2010) to 0.44% (7/1604, 2011) over the same period. Multivariate logistic regression showed that unprotected casual sexual behavior, male gender, illiteracy, drug use, and injection drug use were positively associated with HIV infection risk in the Yi area. Path analysis of the risk factors revealed that casual sexual behavior (0.051) and injection drug use (0.161) were directly associated with HIV infection. However, marital status (0.004), ethnicity (0.017), education level (-0.004), HIV/AIDS-related prevention knowledge (-0.012), and drug use (0.11) had an indirect influence on HIV infection through casual sexual behavior and injection drug use.The prevalence of HIV is high among residents of majority-Yi areas, and injection drug use and casual sexual behavior are risk factors for infection.

Association of MYH9 Polymorphisms with Hypertension in Patients with Chronic Kidney Disease in China.

BACKGROUND/AIMS: This study explored the correlation between hypertension and non-muscle myosin heavy chain 9 (MYH9) gene polymorphisms in Chinese chronic kidney disease (CKD) patients. METHODS: This case-control study included 301 patients with CKD and 293 healthy controls. The E1 haplotype single nucleotide polymorphisms (SNPs) rs3752462 and rs4821480 were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The association between MYH9 polymorphisms and high systolic blood pressure (SBP ≥ 140 mmHg) susceptibility in CKD patients was analysed. RESULTS: The cases and controls had similar genotype and allele distributions at rs3752462 and rs4821480. No GG genotype at rs4821480 was observed. Patients with SBP < 140 mmHg were more likely to have the CC genotype (17.1%) than patients with SBP ≥ 140 mmHg (4.3%) (P = 0.001). Creatinine clearance (OR = 0.99, 95% CI = 0.98-0.10, P = 0.01) was associated with SBP in patients with CKD. The risk of SBP ≥ 140 mmHg was 0.24-fold greater among patients with the CC genotype than among patients with the TT genotype (P = 0.002). CONCLUSION: The rs3752462 polymorphism of MYH9 is associated with SBP in patients with CKD. The T allele in the dominant model was associated with an elevated risk for high SBP.

Experimental study on an in vitro vascular tensile stress loading device / 医用生物力学

Objective To develop an in vitro vascular tensile stress loading device and study the distributions of tensile stress and tensile strain on the elastic basement membrane (silicone sheet). Method The in vitro vascular tensile stress loading device which simulated the human hemodynamic environment was developed based on the elastic basement membrane deformation loading technology. The images of grid points before and after the stretch of the silicon sheet were recorded by camera and transformed into the digital images. The characteristics for the location of the grid points were calculated by using Matlab software, so as to obtain the strain distribution on the silicon sheet. Experiments were conducted on the silicon sheet by using the universal material testing machine, so as to calculate the mechanical parameters of the silicon sheet. The finite element model was established according to the mechanical parameters, and the distribution of tensile stress and tensile strain on the silicon sheet was simulated and calculated. The experimental results and simulative results were then compared. Results The finite element results were basically in accordance with the experimental results. The maximum value of tensile stress and tensile strain appeared on the loading point, while the stress and strain in intermediate area were comparatively homogeneous. 60% of the intermediate area in the silicone sheet could be regarded as homogeneous strain fields Conclusions The research finding can provide experimental techniques for the dynamic culture of vascular endothelial cells and the research on cell mechanics in the future.

Geographical variations in risk factors associated with HIV infection among drug users in a prefecture in Southwest China.

BACKGROUND: Previous studies have shown inconsistent or even contradictory results for some risk factors associated with HIV infection among drug users, and these may be partially explained by geographical variations. METHODS: Data were collected from 11 methadone clinics in the Liangshan Yi Autonomous Prefecture from 2004 to 2012. A non-spatial logistical regression model and a geographically weighted logistic regression model were fitted to analyze the association between HIV infection and specific factors at the individual level. RESULTS: This study enrolled 6,458 patients. The prevalence of HIV infection was 25.1 %. The non-spatial model indicated that being divorced was positively associated with HIV infection. The spatial model also showed that being divorced was positively associated with HIV infection, but only for 49.4 % of individuals residing in some northern counties. The non-spatial model suggested that service sector work was negatively associated with HIV infection. However, the spatial model indicated that service work was associated with HIV infection, but only for 23.0 % of patients living in some western counties. The non-spatial model did not show that being married was associated with HIV infection in our study field, but the spatial model indicated that being married was negatively associated with HIV infection for 12.0 % of individuals living in some western counties. For other factors, the non-spatial and spatial models showed similar results. CONCLUSION: The spatial model may be useful for improving understanding of geographical heterogeneity in the relationship between HIV infection and individual factors. Spatial heterogeneity may be useful for tailoring intervention strategies for local regions, which can consequently result in a more efficient allocation of limited resources toward the control of HIV transmission.

[Survival analysis of AIDS patients in Liangshan prefecture, Sichuan province from 1995 to 2012].

OBJECTIVE: To analyze the survival time and its related factors among AIDS patients in Liangshan prefecture of Sichuan province from 1995 to 2012. METHODS: A retrospective cohort study was conducted to analyze the information of 5 263 AIDS patients. The data were collected from Chinese HIV/AIDS Comprehensive Information Management System. Life table method was applied to calculate the survival proportion, and Kaplan-Meier and Cox proportion hazard regression model were used to identify the factors related to survival time. RESULTS: Among 5 273 AIDS patients, 819 (15.6%)died of AIDS related diseases; 2 782(52.9%) received antiretroviral therapy. The average survival time was 126.7 (117.1-136.2) months, and the survival rate in 1, 5, 10, 15 years were 95.4%, 78.8%, 54.2%, and 31.8% respectively. Univariate analysis showed a significant difference in survival time of age diagnosed as AIDS patients, nationality, transmission route, AIDS phase, CD4(+)T cell counts in the last testing, receiving antiretroviral therapy or not. Multivariate Cox regression showed age diagnosed AIDS below 50 years old ( < 15 years old:HR = 0.141, 95%CI:0.036-0.551;15-49 years old:HR = 0.343, 95%CI:0.241-0.489), HIV infection diagnosed phase (HR = 0.554, 95%CI:0.432-0.709), CD4(+)T cell counts last testing ≥ 350/µl (HR = 0.347, 95%CI:0.274-0.439) reduced the risk of dying of AIDS related diseases among AIDS patients. The patients having not received antiretroviral therapy had a higher risk of death(HR = 3.478, 95%CI:2.943-4.112) compared to those who received antiretroviral therapy. CONCLUSION: Survival time of AIDS patients was possibly mainly influenced by the age of diagnosed as AIDS patients, AIDS phase, CD4(+)T cell counts and whether or not received antiretroviral therapy. The early initiation of antiretroviral therapy could extend the survival time.

The impact of social factors on human immunodeficiency virus and hepatitis C virus co-infection in a minority region of Si-chuan, the People's Republic of China: a population-based survey and testing study.

BACKGROUND: While many human immunodeficiency virus (HIV) studies have been performed in Liangshan, most were focused only on HIV infection and based on a sampling survey. In order to fully understand HIV and hepatitis C virus (HCV) prevalence and related risk factors in this region, this study implemented in 2009, included a survey, physical examination, HIV and HCV test in two towns. METHODS: All residents in two towns of the Butuo county were provided a physical examination and blood tests for HIV and HCV, and then followed by an interview for questionnaire. RESULTS: In total, 10,104 residents (92.4%) were enrolled and 9,179 blood samples were collected for HIV and HCV testing, 6,072 were from individuals >14 years old. The rates of HIV, HCV, and HIV/HCV co-infection were 11.4%, 14.0%, and 7.7%, respectively for >14-year-old residents. The 25-34 yr age group had the highest prevalence of HIV, HCV, and HIV/HCV co-infections, reaching 24.4%, 26.2% and 16.0%, respectively. Overall, males had a much higher prevalence of all infections than females (HIV: 16.3% vs. 6.8%, HCV: 24.6% vs. 3.9%, HIV/HCV co-infected: 14.7% vs. 1.1%, respectively; P = 0.000). Approximately half of intravenous drug users tested positive for HIV (48.7%) and 68.4% tested positive for HCV. Logistic regression analysis showed that five factors were significantly associated with HIV and HCV infection: gender (odds ratio [OR]  = 5.8), education (OR = 2.29); occupation (student as reference; farmer: OR = 5.02, migrant worker: OR = 6.12); drug abuse (OR = 18.0); and multiple sexual partners (OR = 2.92). Knowledge of HIV was not associated with infection. CONCLUSION: HIV and HCV prevalence in the Liangshan region is very serious and drug use, multiple sexual partners, and low education levels were the three main risk factors. The government should focus on improving education and personal health awareness while enhancing drug control programs.

HIV-, HCV-, and co-infections and associated risk factors among drug users in southwestern China: a township-level ecological study incorporating spatial regression.

BACKGROUND: The human immunodeficiency virus (HIV) and hepatitis C virus (HCV) are major public health problems. Many studies have been performed to investigate the association between demographic and behavioral factors and HIV or HCV infection. However, some of the results of these studies have been in conflict. METHODOLOGY/PRINCIPAL FINDINGS: The data of all entrants in the 11 national methadone clinics in the Yi Autonomous Prefecture from March 2004 to December 2012 were collected from the national database. Several spatial regression models were used to analyze specific community characteristics associated with the prevalence of HIV and HCV infection at the township level. The study enrolled 6,417 adult patients. The prevalence of HIV infection, HCV infection and co-infection was 25.4%, 30.9%, and 11.0%, respectively. Prevalence exhibited stark geographical variations in the area studied. The four regression models showed Yi ethnicity to be associated with both the prevalence of HIV and of HIV/HCV co-infection. The male drug users in some northwestern counties had greater odds of being infected with HIV than female drug users, but the opposite was observed in some eastern counties. The 'being in drug rehabilitation variable was found to be positively associated with prevalence of HCV infection in some southern townships, however, it was found to be negatively associated with it in some northern townships. CONCLUSIONS/SIGNIFICANCE: The spatial modeling creates better representations of data such that public health interventions must focus on areas with high frequency of HIV/HCV to prevent further transmission of both HIV and HCV.

The geographic distribution patterns of HIV-, HCV- and co-infections among drug users in a national methadone maintenance treatment program in Southwest China.

BACKGROUND: HIV-, HCV- and HIV/HCV co-infections among drug users have become a rapidly emerging global public health problem. In order to constrain the dual epidemics of HIV/AIDS and drug use, China has adopted a methadone maintenance treatment program (MMTP) since 2004. Studies of the geographic heterogeneity of HIV and HCV infections at a local scale are sparse, which has critical implications for future MMTP implementation and health policies covering both HIV and HCV prevention among drug users in China. This study aimed to characterize geographic patterns of HIV and HCV prevalence at the township level among drug users in a Yi Autonomous Prefecture, Southwest of China. METHODS: Data on demographic and clinical characteristics of all clients in the 11 MMTP clinics of the Yi Autonomous Prefecture from March 2004 to December 2012 were collected. A GIS-based geographic analysis involving geographic autocorrelation analysis and geographic scan statistics were employed to identify the geographic distribution pattern of HIV-, HCV- and co-infections among drug users. RESULTS: A total of 6690 MMTP clients was analyzed. The prevalence of HIV-, HCV- and co-infections were 25.2%, 30.8%, and 10.9% respectively. There were significant global and local geographic autocorrelations for HIV-, HCV-, and co-infection. The Moran's I was 0.3015, 0.3449, and 0.3155, respectively (P < 0.0001). Both the geographic autocorrelation analysis and the geographic scan statistical analysis showed that HIV-, HCV-, and co-infections in the prefecture exhibited significant geographic clustering at the township level. The geographic distribution pattern of each infection group was different. CONCLUSION: HIV-, HCV-, and co-infections among drug users in the Yi Autonomous Prefecture all exhibited substantial geographic heterogeneity at the township level. The geographic distribution patterns of the three groups were different. These findings imply that it may be necessary to inform or invent site-specific intervention strategies to better devote currently limited resource to combat these two viruses.

The changing trends of HIV/AIDS in an ethnic minority region of China: modeling the epidemic in Liangshan prefecture, Sichuan Province.

OBJECTIVE: This study was to investigate the HIV current situation in Liangshan prefecture, in order to predict prevalence and transmission trends. METHODS: Region-specific population, behavior, serosurveillence, and policy/program data (from 1995 to 2010) were gathered from various local and national organizations and applied to the Asian Epidemic Model (AEM) and used to derive estimates of future HIV prevalence, epidemic trends, and outcomes of intervention strategies. RESULTS: The AEM projections for 2020 included increased number of people living with HIV (PLHIV; to 136 617), increased HIV prevalence (2.51%), and 8037 deaths from acquired immunodeficiency syndrome (AIDS) in this region. However, the overall HIV incidence rate (per 10 000) was projected to decline from 27 in 2015 to 22 in 2020, largely due to a predicted decrease in HIV infection rate (per 10 000) from 658 in 2013 to 621 in 2020 among intravenous drug users. In contrast, the cases of HIV infection per 10 000 was projected to increase from 420 in 2010 to 503 in 2020 among men who have sex with men, and from 8 in 2010 to 15 in 2020 among the general population. The predominant risk factor for HIV transmission over the next decade in Liangshan was casual sex. Community-based outreach strategies to reduce injected drug use and casual sex, and to promote condom use, were predicted as effective interventions to decrease HIV transmission. CONCLUSION: Implementation of a comprehensive public health program, with targeting to the region-specific at-risk populations, will help to mitigate HIV/AIDS spread in Liangshan.