Immune Dysfunction and Coinfection with Human Immunodeficiency Virus and Schistosoma japonicum in Yi People.

OBJECTIVE: To explore the association between infections with HIV and Schistosoma japonicum, and to determine the influences of the HIV-S. japonicum coinfections on the immune system of Yi people. METHODS: A block design study was conducted in a Yi county in southwestern China, one of the endemic areas of both HIV/AIDS and S. japonicum in China. All participants were screened for HIV antibodies and S. japonicum antibodies (SjAb) and were classified into four groups: HIV(+)/S. japonicum(-), HIV(-)/S. japonicum (+), HIV(+)/S. japonicum(+), and HIV(-)/S. japonicum(-). RESULTS: There were significant differences among the four groups in both CD4+ T lymphocytes and CD8+ T lymphocytes, but no significant difference in CD3+ T lymphocytes. Both the CD4+ T lymphocyte counts and the ratio of CD4+/CD8+ were lower in HIV-infected people compared with those uninfected. People infected with S. japonicum had increased CD4+ T lymphocyte counts but reduced CD8+ T lymphocyte counts. Similarly, the ratio of CD4+/CD8+ was higher in S. japonicum-infected people compared with those uninfected. People coinfected with HIV and S. japonicum had lower CD4+ T lymphocyte counts, lower ratio of CD4+/CD8+, and higher CD8+ T lymphocyte counts compared with those infected with HIV only or S. japonicum only. People infected with HIV only and those coinfected with HIV and S. japonicum had a higher level of IFN-γ compared with people with no infection. There were no significant differences between people infected with HIV only and with S. japonicum only in the levels of IFN-γ and IL-10. CONCLUSIONS: People coinfected with HIV and S. japonicum might have a suppressed immune function because of a decrease in CD4+ T lymphocyte counts, a lowered ratio of CD4+/CD8+, and an increase in CD8+ T lymphocyte counts. Coinfection with HIV and S. japonicum would alter the level of IFN-γ in plasma.

Prevalence of and risk factors associated with Cryptosporidium infection in an underdeveloped rural community of southwest China.

BACKGROUND: Cryptosporidium spp. is an important intestinal protozoan causing diarrhea in humans, livestock, and wild animals. Cryptosporidium infection remains a major public health issue, but its epidemiology in humans is still unclear, particularly in rural China. This study was designed to determine the prevalence of and risk factors associated with Cryptosporidium infection in a rural southwestern Chinese community. METHODS: A community-based cross-sectional survey was conducted among 687 residents of a small town in a Yi autonomous prefecture of southwest China in 2014. Blood samples were examined using a broad set of quality-controlled diagnostic methods for hepatitis B virus (HBV) and human immunodeficiency virus (HIV). Stool specimens were processed using the modified acid-fast staining method, and microscopically examined for Cryptosporidium infection. Univariable and multivariable analyses were performed to determine the risk factors associated with Cryptosporidium infection. RESULTS: The majority of the participants were Yi people with poor living conditions and unsatisfactory hygiene habits, and the study area was of very low socioeconomic status. Of the 615 individuals included in the analysis, 14 (2.3%) were HIV positive, 51 (8.3%) were infected with HBV, and 74 (12.0%) had Cryptosporidium infection. The prevalences of HIV/HBV, HIV/Cryptosporidium, and HBV/Cryptosporidium co-infections were 0.3%, 0.3%, and 1.8%, respectively. The prevalence of HBV infection was higher in individuals with Cryptosporidium infection (χ 2 = 5.00, P = 0.03). Owning livestock or poultry was an important risk factor for Cryptosporidium infection (aOR = 2.27, 95% CI: 1.01-5.08, P < 0.05). Cryptosporidium infection was significantly associated with HBV infection (aOR = 3.42, 95% CI: 1.47-7.92, P < 0.01), but not with HIV infection (aOR = 0.57, 95% CI: 0.07-4.39, P = 0.59). CONCLUSIONS: The prevalence of Cryptosporidium infection was high in the rural area of southwestern China that was investigated, and there was a significant association between HBV infection and Cryptosporidium infection. Further investigations are needed to determine the significance of Cryptosporidium infection in patients infected with HBV.

Multi-host model and threshold of intermediate host Oncomelania snail density for eliminating schistosomiasis transmission in China.

Schistosomiasis remains a serious public health issue in many tropical countries, with more than 700 million people at risk of infection. In China, a national integrated control strategy, aiming at blocking its transmission, has been carried out throughout endemic areas since 2005. A longitudinal study was conducted to determine the effects of different intervention measures on the transmission dynamics of S. japonicum in three study areas and the data were analyzed using a multi-host model. The multi-host model was also used to estimate the threshold of Oncomelania snail density for interrupting schistosomiasis transmission based on the longitudinal data as well as data from the national surveillance system for schistosomiasis. The data showed a continuous decline in the risk of human infection and the multi-host model fit the data well. The 25th, 50th and 75th percentiles, and the mean of estimated thresholds of Oncomelania snail density below which the schistosomiasis transmission cannot be sustained were 0.006, 0.009, 0.028 and 0.020 snails/0.11 m(2), respectively. The study results could help develop specific strategies of schistosomiasis control and elimination tailored to the local situation for each endemic area.

[Advances in researches of molluscicidal microorganisms against Oncomelania hupensis].

The elimination of Oncomelania hupensis snails is important to schistosomiasis control. Recently, the application of molluscicidal organisms is considered as a safe and efficient method for snail elimination. In order to provide scientific evidences for effective control of O. hupensis and schistosomiasis, this paper summarizes the researches of molluscicidal microorganisms against O. hupensis.

Prevalence and risk factors of Ascaris lumbricoides (Linnaeus, 1758), Trichuris trichiura (Linnaeus, 1771) and HBV infections in Southwestern China: a community-based cross sectional study.

BACKGROUND: Intestinal helminths do not cause severe diseases in general, however, when combined with other diseases such as immunodeficiency diseases, there would be massive complications. Infections with Hepatitis B Virus (HBV) may lead to immunological disturbances and defects of cellular immunity and there is a need of clarification whether HBV infections are associated with infections with intestinal helminths. METHODS: A community-based cross sectional study was conducted in Tezi town, Puge County of the Liangshan Prefecture, southwestern China from October 23rd to November 3rd, 2014. Four hundred and thirty eight people (median age = 37 years, IQR = 22-49) were enrolled in this study. Modified Kato-Katz thick smear was used to detect intestinal helminths. HBV DNA was quantified to confirm HBV infection. RESULTS: Among the 438 participants, 9.1%, 13.5% and 30.6% were infected with HBV, A. lumbricoides (L., 1758) and T. trichiura (L., 1771), respectively; 7.1% (30/438) were infected with both A. lumbricoides and T. trichiura and 2.3% (10/438) were co-infected with HBV and A. lumbricoides. The multivariate logistic regression analysis showed that age (21-30 years versus >50 years: OR = 6.66, 95% CI = 2.15-20.68), drug abuse (OR = 6.96, 95% CI = 1.11-43.90), A. lumbricoides infection (OR = 3.60, 95% CI = 1.48-8.75), fertilization with faeces after disposal (OR = 0.15, 95% CI = 0.04-0.47) and working on a farm (OR = 4.59, 95% CI = 1.44-14.63) were significantly associated with HBV infection. Having toilets at home was negatively related to A. lumbricoides infection (OR = 0.52, 95% CI = 0.27-0.98) and T. trichiura infection (OR = 0.48, 95% CI = 0.28-0.80). CONCLUSIONS: Ascaris lumbricoides was independently associated with HBV infection, and faeces might be the medium of HBV transmission. Improving hygiene conditions and habits are essential to reduce the risks of A. lumbricoides and T. trichiura infections.

[Analysis of relationship between natural death of Oncomelania hupensis snails and water level in Eastern Dongting Lake district].

OBJECTIVE: To study the reasons of natural death of Oncomelania hupensis snails by comparing the differences of the indicator days covered with water (DCW) in snail marshland and non-snail marshland around the build of Three Gorges Dam in Eastern Dongting Lake areas. METHODS: Two marshlands were selected, one was a non-snail marshland (Qianliang Lake) and another was a snail marshland (Junshan Park). The measuring points were set through the mechanical sampling. The snails and elevation of the points were surveyed, and the data of the water levels from the hydrological station were collected, and then DCWs were calculated. RESULTS: From 1995 to 2013, DCWs of the marshland of natural death of snails were all more than that of the snail marshland (P < 0.01). In Qianliang Lake marshland, the difference between DCW before natural death and DCW from natural death until the dam was not significant (P = 0.23), while DCWs of the two stages both were more than that after the dam (P1 = 0.045, P2 = 0.002). Before the build of the dam, DCW of the Qianliang Lake marshland of natural death of snails was more than that after the build of the dam (P = 0.013), and there was the same situation in Junshan Park marshland (P = 0.005). The relationship between snail density and DCW was not significant in Junshan Park marshland (r(s) = 0.008, P = 0.914), and the reference range of DCW of all the measuring points was 76-251 days. CONCLUSION: In the eastern Dongting Lake district, the build of Three Gorges Dam and DCW may be not the direct factors affecting the natural death of snails and the latter may change the distribution of snails.

[Comparative analysis of epidemiological situation and trategies to control schistosomiasis between China and African countries].

Schistosomiasis is a neglected tropical disease which is socioeconomically devastating and a significant cause of morbidity in endemic countries or regions. Some countries and regions have brought down the prevalence of schistosomiasis through positive prevention and control programs. However, in the past few years, with the social and economic development and globalization, re-emergence and spread of schistosomiasis led to a growing concern that new endemic areas may occur. This article analyzes the epidemiological situation and the strategies to control schistosomiasis in China and African countries.

Association between maternal HIV infection and low birth weight and prematurity: a meta-analysis of cohort studies.

BACKGROUND: To assess the association between maternal human immunodeficiency virus (HIV) infection and low birth weight (LBW)/prematurity (PTD), we conducted a meta-analysis of cohort studies of HIV infected and uninfected women. METHODS: Several English and Chinese databases were searched (updated to May 2015) to find the studies reporting infant outcomes associated with exposure to maternal HIV infection during pregnancy. Relevant articles were manually selected based on several inclusion and exclusion criteria. RESULTS: Fifty-two cohort studies including 15,538 (for LBW) and 200,896 (for PTD) HIV infected women met the inclusion criteria. There was significant heterogeneity among studies for maternal HIV infection associated with LBW/PTD (I(2) = 71.7%, P < 0.05, and I(2) = 51.8%, P < 0.05 for LBW and PTD, respectively). The meta-analysis demonstrated that the maternal HIV infection was significantly associated with both LBW (pooled odds ratio (OR): 1.73, 95% confidence interval (CI): 1.64, 1.82, P < 0.001) and PTD (pooled OR: 1.56, 95% CI: 1.49, 1.63, P < 0.001). No significant difference in the relationship between maternal HIV infection and adverse pregnancy outcomes was detected among the groups of different study periods. HIV infected women were at slightly higher risk of LBW in developing countries compared with women in developed countries (OR: 2.12 (95% CI: 1.81, 2.48) vs. 1.75 (95% CI: 1.44, 2.12)). Antiretroviral drugs usage did not significantly change the associations of maternal HIV exposure with LBW and PTD. CONCLUSIONS: HIV infected women were at higher risk of having a low birth weight infant or a preterm delivery infant compared with uninfected women. Such associations did not change significantly over time or were not significantly affected by the usage of antiretroviral drugs.

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.

Three Gorges Dam: Impact of Water Level Changes on the Density of Schistosome-Transmitting Snail Oncomelania hupensis in Dongting Lake Area, China.

BACKGROUND: Schistosomiasis remains an important public health issue in China and worldwide. Oncomelania hupensis is the unique intermediate host of schistosoma japonicum, and its change influences the distribution of S. japonica. The Three Gorges Dam (TGD) has substantially changed the ecology and environment in the Dongting Lake region. This study investigated the impact of water level and elevation on the survival and habitat of the snails. METHODS: Data were collected for 16 bottomlands around 4 hydrological stations, which included water, density of living snails (form the Anxiang Station for Schistosomiasis Control) and elevation (from Google Earth). Based on the elevation, sixteen bottomlands were divided into 3 groups. ARIMA models were built to predict the density of living snails in different elevation areas. RESULTS: Before closure of TGD, 7 out of 9 years had a water level beyond the warning level at least once at Anxiang hydrological station, compared with only 3 out of 10 years after closure of TGD. There were two severe droughts that happened in 2006 and 2011, with much fewer number of flooding per year compared with other study years. Overall, there was a correlation between water level changing and density of living snails variation in all the elevations areas. The density of living snails in all elevations areas was decreasing after the TGD was built. The relationship between number of flooding per year and the density of living snails was more pronounced in the medium and high elevation areas; the density of living snails kept decreasing from 2003 to 2014. In low elevation area however, the density of living snails decreased after 2003 first and turned to increase after 2011. Our ARIMA prediction models indicated that the snails would not disappear in the Dongting Lake region in the next 7 years. In the low elevation area, the density of living snails would increase slightly, and then stabilize after the year 2017. In the medium elevation region, the change of the density of living snails would be more obvious and would increase till the year 2020. In the high elevation area, the density of living snails would remain stable after the year 2015. CONCLUSION: The TGD influenced water levels and reduced the risk of flooding and the density of living snails in the study region. Based on our prediction models, the density of living snails in all elevations tends to be stabilized. Control of S. japonica would continue to be an important task in the study area in the coming decade.

[Epidemic characteristics and security implications of Africa schistosomiasis on people who go to Africa].

With the economic globalization, and the economic and trade cooperation and cultural communication between China and African countries, more and more Chinese people go to Africa for work or travel. However, there is a quick increase of imported schistosomiasis patients who return from Africa. This paper analyzes the security implications of epidemic characteristics of Africa schistosomiasis on the people who go to Africa, and put forward several suggestions to help them to prevent from schistosomiasis.

[Hemocyte morphology and classification in Oncomelania hupensis].

Hemocytes were collected from Oncomelania hupensis in Junshan, Hunan Province and Puge, Sichuan Province, respectively, and stained with Giemsa solution for light microscopic examination. The cells were classified morphologically. Five types of hemocytes were identified, viz., large acidophilic hyalinocytes, small acidophilic hyalinocytes, basophilic hyalinocytes, basophilic small granulocytes and basophilic large granulocytes. The proportion of small acidophilic hyalinocytes was the most abundant hemocyte [36.7% (229/624) in snails from Junshan and 31.7% (257/810) in snails from Puge], followed by basophilic hyalinocyte [23.1% (144/624) in Junshan and 24.4% (198/810) in Puge]. Basophilic large granulocyte was about 9.3% (58/624) in Junshan and 11.6% (94/810) in Puge. The length of large acidophilic hyalinocytes was the maximum and its nucleocytoplasmic ratio was minimum, followed by small acidophilic hyalinocytes. The length of basophilic cells was shorter and its nucleocytoplasmic ratio was smaller than those of acidophilic cells. There was no significant difference in cellular constituents of hemocytes and the morphological features of hyalinocytes between the snails from Junshan and Puge, while the length and nucleocytoplasmic ratio of granulocytes in Junshan snails were smaller than those of Puge ones.

[Contrastive analysis of environmental factors between Oncomelania hupensis snail marshland and snail natural death marshland in eastern Dongting Lake schistosomiasis endemic areas].

OBJECTIVE: To study the reasons of natural death of Oncomelania hupensis snails in marshland by comparing the differences of environmental factors between snail marshland and non-snail marshland in East Dongting Lake schistosomiasis endemic areas. METHODS: Two adjoining marshlands were selected, one was a snail marshland and another was a non-snail marshland. The measuring points were set by grid of "20 m x 20 m". The soil moisture, elevation, soil pH and temperature of the points were measured, and the snails of the points were surveyed. RESULTS: The elevation, soil pH and temperature of the snail natural death marshland were all lower than those of the snail marshland (P < 0.01). The soil moisture, elevation, soil pH and temperature of different snail densities in the snail marshland were different (P < 0.05). The soil moisture of the non-snail group was higher than that of other four groups (P < 0.01) and the soil moisture of the group with 0-11 snails per frame was lower than that of other four groups (P < 0.01). The elevation of the group with 0-11 snails per frame was lower than that of the group with 24-39 snails per frame and the group with more than 39 snails per frame (P < 0.05). The soil pH of the group without snails was higher than that of other four groups (P < 0.01) and the soil temperature of the group with 0-11 snails per frame was lower than that of the group with 24-39 snails per frame. The differences of soil moisture and elevation of different death snail densities were not significant, while the differences of soil pH and temperature were significant. The soil pH of the non-snail died group was higher than that of the 2-died, 3-died and more than 3-died groups (P < 0.05). The soil temperature of the non-snail died group was higher than that of other four groups (P < 0.05). CONCLUSION: The elevation, soil pH and soil temperature within the range of the research may be the factors affecting the snail natural death and the soil moisture, elevation, soil pH and soil temperature may be the factors affecting the distribution of snails.

Identification of optimum scopes of environmental factors for snails using spatial analysis techniques in Dongting Lake Region, China.

BACKGROUND: Owing to the harmfulness and seriousness of Schistosomiasis japonica in China, the control and prevention of S. japonica transmission are imperative. As the unique intermediate host of this disease, Oncomelania hupensis plays an important role in the transmission. It has been reported that the snail population in Qiangliang Lake district, Dongting Lake Region has been naturally declining and is slowly becoming extinct. Considering the changes of environmental factors that may cause this phenomenon, we try to explore the relationship between circumstance elements and snails, and then search for the possible optimum scopes of environmental factors for snails. METHODS: Moisture content of soil, pH, temperature of soil and elevation were collected by corresponding apparatus in the study sites. The LISA statistic and GWR model were used to analyze the association between factors and mean snail density, and the values in high-high clustered areas and low-low clustered areas were extracted to find out the possible optimum ranges of these elements for snails. RESULTS: A total of 8,589 snail specimens were collected from 397 sampling sites in the study field. Besides the mean snail density, three environmental factors including water content, pH and temperature had high spatial autocorrelation. The spatial clustering suggested that the possible optimum scopes of moisture content, pH, temperature of the soil and elevation were 58.70 to 68.93%, 6.80 to 7.80, 22.73 to 24.23°C and 23.50 to 25.97 m, respectively. Moreover, the GWR model showed that the possible optimum ranges of these four factors were 36.58 to 61.08%, 6.541 to 6.89, 24.30 to 25.70°C and 23.50 to 29.44 m, respectively. CONCLUSION: The results indicated the association between snails and environmental factors was not linear but U-shaped. Considering the results of two analysis methods, the possible optimum scopes of moisture content, pH, temperature of the soil and elevation were 58.70% to 68.93%, 6.6 to 7.0, 22.73°C to 24.23°C, and 23.5 m to 26.0 m, respectively. The findings in this research will help in making an effective strategy to control snails and provide a method to analyze other factors.

[Distribution of univalvia molluscs in area with natural decline of Oncomelania hupensis snails in Eastern Dongting Lake area].

OBJECTIVE: To understand the distribution of univalvia molluscs in Eastern Dongting lake area where the Oncomelania hupensis is extinct, so as to explore the causes of extinction and to provide the evidence for formulating schistosomiasis control strategy. METHODS: The univalvia molluscs of the Qianliang Lake district, Jianxin District and Junshan Park were investigated in August of 2013. All the collected snails were classified and identified. The data were analyzed by using the method of Shapiro-Wilk normality test and non-parametric test. The ecological biodiversity differences from each district were compared by the biodiversity indexes. RESULTS: The univalvia molluscs collected were from 6 species in 3 families in Gastropoda class, namely Oncomelania hupensis Gredler in Pomatiopsidae family, Parafossarulus striatulus, Alocinma longicornis, Parafossarulus sineasis, Bithynia fuchsisana in Bithyniidae family, and one genus provisioy nally named Radix in Lymaneidae family. In Junshan Park, a total of 4553 snails were collected, among which 1264 were Oncomelania snails. In Jianxin District, 336 univalvia molluscs were collected, and no Oncomelania snails were found. In Qianliang Lake district, there were only 7 Alocinma longicornis snails, 2 Parafossarulus sinensis snails and 1 Parafossarulus striatulus snail collected. There were significant differences among the distributions of the samples from the three districts (chi2 = 166.225, P < 0.01) .The Simpson's diversity indexes in Qianliang Lake area, Jianxin Dis- trict and Junshan Park were 0.4028, 0.7186 and 0.6788, respectively, and the Shannon-Wiener indexes of the 3 areas were 0.7215, 1.4313 and 1.1999, respectively. CONCLUSIONS: With the extinction of Oncomelania snails, the species and quantities of other snails become rare in Qianliang Lake area. Whether their causes are relevant is worth further studying.

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.

[Evaluation of comprehensive measures with emphasis on schistosomiasis infectious source control at embankment level].

OBJECTIVE: To evaluate the effects of comprehensive measures with emphasis on schistosomiasis infectious source control at the embankment level. METHODS: The comprehensive measures with emphasis on schistosomiasis infectious source control were carried out, and the data of human and Oncomelania snail infection rates were collected and analyzed statistically at embankment levels. RESULTS: In Anbao Embankment, except the other comprehensive measures were performed, 2606 buffaloes were removed. The infection rates of residents reduced from 8.04% before the intervention to 0.7% after the intervention, and the infection rates of snails reduced from 0.56% to 0.05%. In Anli Embankment, 535 buffaloes were removed. In the third year after the intervention, the infection rates of residents reduced from 5.87% to 1.09%, and the infection rates of snails reduced from 0.17% to 0.07%. In Anzao Embankment, 62 buffaloes were removed. In the second year after the intervention, the infection rates of residents reduced from 2.67% to 0.39%, and the infection rates of snails reduced from 1.12% to 0.00%. In Anchang Embankment, the buffaloes were not removed. The human infection rates reduced from 1.76% before the intervention to 1.23% after the intervention. CONCLUSION: The comprehensive measures with emphasis on schistosomiasis infectious source control, especially the buffalo's removal, are effective in the control of schistosome infection rates of residents and snails.

[Natural growth and decline of Oncomelania hupensis snails in marshland of Qianliang Lake District in Eastern Dongting Lake area, China].

OBJECTIVE: To understand the change trend of Oncomelania hupensis snails in the bottomland areas of Qian Liang Lake district in Eastern Dongting Lake area so as to provide the evidence for formulating a schistosomiasis control strategy. METHODS: The monitoring data of snails of Qianliang Lake district from 1988 to 2011 were collected retrospectively and analyzed by using the method of the trend Chi-square test. The correlations among the snail density indicators were analyzed. RESULTS: 1988 to 2011, the area of snails surveyed did not change and was 433.2 hm(2). The monitoring data showed that the change trend of the density of living snails and the schistosome infection rates of snails were not obvious (P > 0.05), but the mortality of snails showed a falling trend (P < 0.05); There were positive correlations between the average density of infected snails and the mortality of snails (r = 0.640, P < 0.05) , the infection rate of snails (r = 0.639, P < 0.05) , and the average density of living snails (r = 0.646, P < 0.05) , respectively. There was no correlation among other snail indicators. In 1999, only 7 snails were found, of them, only one snail was alive. The alive snails were not found after 2000. CONCLUSION: In the bottomland areas of Qianliang Lake district, the change trend of the density of alive snails were not obvious from 1988 to 1998, but the number of snails underwent a sharp drop in 1999 and snails have been not found till now.