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The HIV/AIDS cases and proportion in older people are continuously and rapidly increasing in China, especially in males. However, the transmission mechanism is not well understood. This study aims to explore the transmission mechanism of HIV/AIDS and potential ways to prevent or control HIV/AIDS transmission in a city in southwestern China. Data from multiple sources, including HIV/AIDS case reports in 2010–2020, a survey of HIV/AIDS cases in 2020, and sentinel surveillance data of female sex workers (FSWs) in 2016–2020 were analyzed. We explored the transmission mechanism of HIV/AIDS cases aged 50 years and older. In this city, the number of newly reported HIV/AIDS cases aged 50 years and older increased from 2010 to 2019, and decreased in 2020. The number of male and female cases aged 50 years and older both increased rapidly in 2017–2019, though the number of male cases was larger than that of female. The survey data showed that 84.7% of older male cases reported commercial sexual behavior, among whom 87.7% reported never using condom and 37.6% reported more than 10 times of commercial sexual behaviors in 1 year. In terms of price of sexual behavior, 68.3% of older male cases sought low-tier FSWs among whom the HIV/AIDS positive rate was 5.4% from the sentinel surveillance data. These results suggested HIV transmission between older men and low-tier FSWs through commercial sexual behavior. Among female cases aged 50 years and older, most reported non-marital and non-commercial heterosexual (60.5%) or regular sexual partner (31.4%) transmission, suggesting that they were infected by their spouse/regular sexual partner. Data of matched couples showed that most male cases had both marital sexual behavior and commercial sexual behavior, or acquired HIV through commercial sexual behavior, while most female cases had only marital sexual behavior. Based on these findings, we proposed a transmission mode of that local older male people and FSWs are transmitting bilaterally through commercial sexual behavior, and local older male people are spreading to local older female people through spouse or regular sexual partner route. By studying data from multiple sources, we explored the HIV transmission mode among older people. In the meantime, we found that marital status had a different impact on male and female old people in their sex behaviors.

Background The COVID-19 spread worldwide quickly. Exploring the epidemiological characteristics could provide a basis for responding to imported cases abroad and to formulate prevention and control strategies in areas where COVID-19 is still spreading rapidly. Methods The number of confirmed cases, daily growth, incidence and length of time from the first reported case to the end of the local cases (i.e., non-overseas imported cases) were compared by spatial (geographical) and temporal classification and visualization of the development and changes of the epidemic situation by layers through maps. Results In the first wave, a total of 539 cases were reported in Sichuan, with an incidence rate of 0.6462/100,000. The closer to Hubei the population centres were, the more pronounced the epidemic was. The peak in Sichuan Province occurred in the second week. Eight weeks after the Wuhan lockdown, the health crisis had eased. The longest epidemic length at the city level in China (except Wuhan, Taiwan, and Hong Kong) was 53 days, with a median of 23 days. Spatial autocorrelation analysis of China showed positive spatial correlation (Moran’s Index > 0, p Conclusions After the closure of the outbreak city, appropriate isolation and control measures in the next 8 weeks were key to control the outbreak, which reduced the peak value and length of the outbreak. Some countries with improved epidemic situations need to develop a continuous “local strategy at entry checkpoints” to to fend off imported COVID-19.

Antiretroviral therapy (ART) has been introduced recently and has significantly impacted morbidity and mortality, but can also engender drug resistance. To identify the prevalence of HIV-1 drug resistance (HIVDR) among patients with antiretroviral therapy failure in Sichuan during the period from 2010 to 2016, we carried out a longitudinal study in Sichuan, a province with the highest HIV/AIDS prevalence in China. The data and blood samples were collected from HIV/AIDS patients who received ART for more than half a year. Overall 5,512 sequences were completed from 7,059 ART-failure patients, and 2,499 individuals were identified as drug resistant. Among those with HIVDR mutations identified, 25.37% were against non-nucleoside reverse transcriptase inhibitors (NNRTIs), and 1.60% was against nucleoside reverse transcriptase inhibitors (NRTIs). NRTI-resistant drugs were mainly lamivudine (3TC) (57.77%) and emtricitabine (FTC), while NNRTI-resistant drugs were mainly nevirapine (NVP) (91.13%) and efavirenz (EFV) (72.81%). The most common recombination subtypes of HIV-1 in sequenced samples were CRF07_BC (circulating recombinant form, CRF) (41.42%), followed by CRF01_AE (40.77%). Moreover, drug resistance rate increased with the prolongation of treatment time (χ2 = 14.758, P < 0.05). The overall prevalence of acquired drug resistance in HIV-1 infected patients in Sichuan was 5.47%, which has remained relatively stable from 2010 to 2016. HIV-1 CRF01_AE and CRF07_BC subtypes were the main epidemic strains, and the possibility of resistance was higher in CRF01_AE subtypes. The current study highlights the importance of acquired drug resistance surveillance over a long period.

To evaluate the attitudes towards informing senile patients about the diagnosis among Chinese clinicians, patients and their relatives, and explore the factors restricting senior citizens from implementing their right of informed consent independently, a cross-sectional study was conducted in Beijing in June 2013. 100 clinicians, 250 competent inpatients and their closest relatives chosen by stratified random sampling method were measured by a questionnaire anonymously. There were 78 doctors, 203 patients and 218 relatives who responded, and 60.6% of the patients were over 65 years old. As with the young and middle-aged, almost all senile patients desired to learn about their condition. However, to avoid dispute or other troubles, 52.9% of medical staff tended to inform the family members first, and 9.5% of relatives were reluctant to disclose all the information to senile patients for fear of embarrassment or other undesirable negative effects. So increasing the communication skills training for clinicians, abandoning the rule of family members’ consent for competent patients and publicising the positive effects of informed consent are the key measures to safeguard senile patients’ rights in China.

We report a novel HIV circulating recombinant form (CRF B/C) identified from 10 epidemiologically unlinked individuals in Sichuan province, China, all self-report infected by heterosexual behavior. Sequencing and analyzing the near-full-length genome of these strains revealed this recombinant form to be composed of subtype B (China and Thailand) and subtype C (China and India), with three subtype B segments inserted into the pol, vpu, and nef regions of the subtype C backbone. To our knowledge, this identified HIV-1 recombinant form differs from previously documented B/C forms in its distinct backbone, inserted fragment size, and breakpoints. In agreement with the current HIV nomenclature system, this novel recombinant form constitutes a novel CRF (CRF85_BC). Our present findings further enrich the diversity of the prevalent HIV-1 CRFs in China.

This study describes the current situation and projects dynamic trends for HIV prevalence in a highly endemic area of China, Liangshan Prefecture, Sichuan Province. Epidemiological, behavioral, and population census data from multiple sources were analyzed to extract input for an Asian Epidemic Model (AEM). Fitting curves to historical trends in HIV prevalence were used as a baseline, and future intervention scenarios were explored using the AEM. For 2007, modeled data suggested approximately 0.5% adult HIV prevalence in Liangshan, with an estimated 17,450 people living with HIV/AIDS and 3,400 new infections. With current high risk behaviors, the model predicts that adult prevalence will rise to 1.5% by 2020. Increased condom use and clean needle exchange among injection drug users (IDUs) have slowed the epidemic. The source of new HIV infections will change from a preponderance of IDU-related infections in 2007 (65.9%) to a mixed epidemic in 2020 (general population heterosexuals 45.2%, IDU 38.6%, homosexual transmission between men 12.7%, female sex workers and their clients 3.5%). We anticipate rising prevalence, stable incidence, and higher representation of sexual transmission over time. Prevention investments should target specific interventions toward sub-groups at highest risk, given that both IDUs and men who have sex with men will likely represent a majority of cases and serve as a bridge population.

China's commitment to implementing established and emerging HIV/AIDS prevention and control strategies has led to substantial gains in terms of access to antiretroviral treatment and prevention services, but the evolving and multifaceted HIV/AIDS epidemic in China highlights the challenges of maintaining that response. This study presents modeling results exploring the potential impact of HIV vaccines in the Chinese context at varying efficacy and coverage rates, while further exploring the potential implications of vaccination programs aimed at reaching populations at highest risk of HIV infection. A preventive HIV vaccine would add a powerful tool to China's response, even if not 100% efficacious or available to the full population.

Three community-based surveys recruited 4,310 injection drug users (IDUs) in China from 2004 to 2006. Of the participants, 54.4% were ≤ 3-year new IDUs; 63.9% reported injecting more than two times daily; 31.5% shared needles in the last six months; 37.4% shared equipments in the last month; 30.2% reported their regular sex partners injected drugs; and 23.5% had commercial sex, with 52.2% reporting no condom use during last sex. The risky injection practices (sharing needles/equipments and high injection frequency) were less frequent among new IDUs, emphasizing that effective prevention needs to identify and intervene with IDUs early on. The study's limitations are noted.

To examine the prevalence and correlates for needle-sharing among new and long-term injection drug users (IDUs) in Sichuan province, China.Three consecutive cross-sectional surveys were conducted in 6 prefectures of Sichuan province, from 2003 to 2005. Questionnaire-based interviews provided information including socio-demographics, drug-use, sexual behaviors, and HIV-related services. Multivariable logistic regression methodology was used for data analysis.Of 3852 eligible participants, the rates of needle-sharing in the last 6 months for IDUs with a less than one year, one to three year, and more than three year injection history were 19.9%, 29.1%, and 36.3%, respectively. Needle-sharing for IDUs with a less than one-year injection history was independently associated with factors as: being female, having minority background, higher frequency of injection, sharing injecting equipments, ever having had a non-regular sex partner, or a regular sex partner who injected drugs, never had a test on HIV, being recruited in 2005, and from Zigong prefectures of Sichuan. Needle-sharing for IDUs with a 1-3 year injection history were independently associated with receiving less education, having higher frequency of injecting behavior, sharing injecting equipments, ever having had a non-regular sex partner/a regular sex partner who injected drugs, ever having had unprotected sex with a non-regular sex partner, ever having had unprotected sex with a commercial sex partner or client, never attended skill training for HIV/STD prevention, being recruited in 2005 and 2004, and being recruited from Deyang, Zigong, and Liangshan prefectures. Needle-sharing for IDUs with a more than three-year injection history was independently associated with factors as: less education, higher frequency of injecting, sharing injecting equipment, ever had a non-regular sex partner, ever had unprotected sex with a non-regular sex partner, ever had unprotected sex with a commercial sex partner or client, having had regular sex partners who inject drugs, never attended needle exchange programs, being recruited in 2005 and 2004, and being recruited from Deyang, Zigong, and Liangshan prefectures.The rates for both needle/paraphernalia sharing and unprotected sex behaviors were high in the IDUs in Sichuan province. These rates were higher among longer-term IDUs than in new IDUs. Our data underlined that better targeted, in-depth and sustained comprehensive intervention packages which including needle exchange, condom promotion along with distribution, and education, were urgently needed to reduce both IDU-related and sex-related risk behaviors among both new and longer term IDUs.

In mid-July 2005, five patients presented with septic shock to a hospital in Ziyang city in Sichuan, China, to identify the etiology of the unknown reason disease, an epidemiological, clinical, and laboratory study were conducted.An enhanced surveillance program were established in Sichuan, the following activities were introduced: active case finding in Sichuan of (a) laboratory diagnosed Streptococcus suis infection and (b) clinically diagnosed probable cases with exposure history; supplemented by (c) monitoring reports on meningococcal meningitis. Streptococcus suis serotype 2 infection was confirmed by culture and biochemical reactions, followed by sequencing for specific genes for serotype and virulence factors.From June 10 to August 21, 2005, 68 laboratory confirmed cases of human Streptococcus suis infections were reported. All were villagers who gave a history of direct exposure to deceased or sick pigs in their backyards where slaughtering was performed. Twenty six (38%) presented with toxic shock syndrome of which 15 (58%) died. Other presentations were septicaemia or meningitis. All isolates were tested positive for genes for tuf, species-specific 16S rRNA, cps2J, mrp, ef and sly. There were 136 clinically diagnosed probable cases with similar exposure history but incomplete laboratory investigations.An outbreak of human Streptococcus suis serotype 2 infections occurred in villagers after direct exposure to deceased or sick pigs in Sichuan. Prohibition of slaughtering in backyards brought the outbreak to a halt. A virulent strain of the bacteria is speculated to be in circulation, and is responsible for the unusual presentation of toxic shock syndrome with high case fatality.

To study the potential risk factors of human infecting with Streptococcus suis.1: M matched case-control study was conducted. 29 human cases of Streptococcus suis infection in the early phase were included in the case group, Patients' family members, neighbors and peoples who had worked together with patients to handle deceased or sick pigs in the last week were recruited as matched controls. There were 147 controls in total. Both cases and controls received questionnaire investigation including the ways to contact sick/dead pigs. Conditional logistic regression was employed to analyze matching data.According to the results of multivariate analysis, slaughtering (OR = 11.978, 95% CI: 3.355-42.756), carcasses cutting and processing (OR = 3.008, 95% CI: 1.022-8.849) sick/dead pigs were associated with cases related to human Streptococcus suis infection. The attributable risk proportion were 91.65% and 66.76% respectively. The other types of exposures to sick/ dead pigs, including feeding, selling, burying and eating, were not associated with the human Streptococcus suis infection in our study population.Slaughtering, carcasses cutting and processing sick/dead pigs were important risky behavior for humans to be infected by Streptococcus suis.

To describe the clinical and epidemiological features of dead cases with human Streptococcus suis infections, and to find the target population for preventing death and the related indicators.Epidemiological investigation on human Streptococcus suis infections was implemented used unified questionnaires. Analysis on dead cases and survival cases (as contrast) was done.The population with highest fatality rate was in 40-49 age group. 97.37% of dead cases had toxic shock syndrome. The mean interval from onset to admission was 0.76 days, and the mean course was 2.11 days. The progression among dead cases was faster than that among survival cases. Chief clinical manifestations of dead cases that are more frequent than survival cases are purpura (73.68%), diarrhea (50.0%), dyspnea (21.05%), conjunctival congestion (34.21%), etc. Renal impairment and liver involvement in dead cases were more significant than that in survival cases. No significant difference between mean incubation period, exposure rates of main risk factors in dead cases and in survival cases was found.Preventing toxic shock syndrome might reduce the fatality rate. The target population for preventing death is agedor = 40. Liver function and renal function testing might be indicators for monitoring the progression of human Streptococcus suis infections.