Impact factors of Blastocystis hominis infection in persons living with human immunodeficiency virus: a large-scale, multi-center observational study from China

BACKGROUND

Blastocystis hominis (Bh) is zoonotic parasitic pathogen with a high prevalent globally, causing opportunistic infections and diarrhea disease. Human immunodeficiency virus (HIV) infection disrupts the immune system by depleting CD4+ T lymphocyte (CD4+ T) cell counts, thereby increasing Bh infection risk among persons living with HIV (PLWH). However, the precise association between Bh infection risk and HIV-related biological markers and treatment processes remains poorly understood. Hence, the purpose of the study was to explore the association between Bh infection risk and CD4+ T cell counts, HIV viral load (VL), and duration of interruption in antiviral therapy among PLWH.

METHODS

A large-scale multi-center cross-sectional study was conducted in China from June 2020 to December 2022. The genetic presence of Bh in fecal samples was detected by real-time fluorescence quantitative polymerase chain reaction, the CD4+ T cell counts in venous blood was measured using flowcytometry, and the HIV VL in serum was quantified using fluorescence-based instruments. Restricted cubic spline (RCS) was applied to assess the non-linear association between Bh infection risk and CD4+ T cell counts, HIV VL, and duration of interruption in highly active antiretroviral therapy (HARRT).

RESULTS

A total of 1245 PLWH were enrolled in the study, the average age of PLWH was 43 years [interquartile range (IQR): 33, 52], with 452 (36.3%) being female, 50.4% (n = 628) had no immunosuppression (CD4+ T cell counts > 500 cells/μl), and 78.1% (n = 972) achieved full virological suppression (HIV VL < 50 copies/ml). Approximately 10.5% (n = 131) of PLWH had interruption. The prevalence of Bh was found to be 4.9% [95% confidence interval (CI): 3.8-6.4%] among PLWH. Significant nonlinear associations were observed between the Bh infection risk and CD4+ T cell counts (Pfor nonlinearity < 0.001, L-shaped), HIV VL (Pfor nonlinearity < 0.001, inverted U-shaped), and duration of interruption in HARRT (Pfor nonlinearity < 0.001, inverted U-shaped).

CONCLUSIONS

The study revealed that VL was a better predictor of Bh infection than CD4+ T cell counts. It is crucial to consider the simultaneous surveillance of HIV VL and CD4+ T cell counts in PLWH in the regions with high level of socioeconomic development. The integrated approach can offer more comprehensive and accurate understanding in the aspects of Bh infection and other opportunistic infections, the efficacy of therapeutic drugs, and the assessment of preventive and control strategies.

[Epidemiological characteristics and influencing factors of Blastocystis hominis infection among children with diarrhea under five years of age in Guangzhou City]

OBJECTIVE

To investigate the prevalence and influencing factors of Blastocystis hominis infection among children with diarrhea under five years of age in Guangzhou City.

METHODS

Children with diarrhea under 5 years of age admitted to Guangzhou Children's hospital, Guangzhou Maternity and Child Healthcare Hospital and Guangzhou Women and Children's Medical Center during the period between January 1 and December 31, 2020, were enrolled. Participants' demographics, living environments and health status were collected using questionnaire surveys. Stool samples were collected from participants and nucleic acid was extracted. B. hominis infection was identified using PCR assay and sequence alignment, and the factors affecting B. hominis infection among children with diarrhea under 5 years of age were identified using univariate analysis and multivariate logistic regression analysis.

RESULTS

A total of 684 children with diarrhea under 5 years of age were enrolled, including 468 male children and 216 female children, with a mean age of (1.79 ± 1.12) years. The overall prevalence of B. hominis infection was 4.97% [34/684, 95% confidential interval (CI): (3.59%, 6.86%)] among participants, and there was no significant difference in the prevalence of B. hominis infection between children with chronic [7.52% (20/266), 95% CI: (4.92%, 11.33%)] and acute diarrhea [3.35% (14/418), 95% CI: (2.01%, 5.54%)] (χ² = 5.983, P = 0.014). Multivariate logistic regression analysis identified keeping pet [odds ratio (OR) = 6.298, 95% CI: (2.711, 14.633)], drinking non-tap water [OR = 4.522, 95% CI: (1.769, 11.561)], lactose intolerance [OR = 4.221, 95% CI: (1.043, 17.087)], antibiotic use [OR = 0.125, 95% CI: (0.017, 0.944)] and chronic diarrhea [OR = 2.172, 95% CI: (1.018, 4.637)] as factors affecting B. hominis infection among children with diarrhea under 5 years of age in Guangzhou City.

CONCLUSIONS

B. hominis infections is detected in children with diarrhea under five years of age in Guangzhou City. Improving home environments and pet-keeping hygiene is recommended to reduce the likelihood of B. hominis infection among children.

The rapid and efficient strategy for SARS-CoV-2 Omicron transmission control: analysis of outbreaks at the city level

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron (B.1.1.529) variant is highly transmissible with potential immune escape. Hence, control measures are continuously being optimized to guard against large-scale coronavirus disease 2019 (COVID-19) outbreaks. This study aimed to explore the relationship between the intensity of control measures in response to different SARS-CoV-2 variants and the degree of outbreak control at city level.

METHODS

A retrospective study was conducted in 49 cities with COVID-19 outbreaks between January 2020 and June 2022. Epidemiological data on COVID-19 were extracted from the National Health Commission, People's Republic of China, and the population flow data were sourced from the Baidu migration data provided by the Baidu platform. Outbreak control was quantified by calculating the degree of infection growth and the time-varying reproduction number ([Formula: see text]). The intensity of the outbreak response was quantified by calculating the reduction in population mobility during the outbreak period. Correlation and regression analyses of the intensity of the control measures and the degree of outbreak control for the Omicron variant and non-Omicron mutants were conducted, respectively.

RESULTS

Overall, 65 outbreaks occurred in 49 cities in China from January 2020 to June 2022. Of them, 66.2% were Omicron outbreaks and 33.8% were non-Omicron outbreaks. The intensity of the control measures was positively correlated with the degree of outbreak control (r = 0.351, P = 0.03). The degree of reduction in population mobility was negatively correlated with the R_t value (r = - 0.612, P < 0.01). Therefore, under the same control measure intensity, the number of new daily Omicron infections was 6.04 times higher than those attributed to non-Omicron variants, and the R_t value of Omicron outbreaks was 2.6 times higher than that of non-Omicron variants. In addition, the duration of non-Omicron variant outbreaks was shorter than that of the outbreaks caused by the Omicron variant (23.0 ± 10.7, 32.9 ± 16.3, t = 2.243, P = 0.031).

CONCLUSIONS

Greater intensity of control measures was associated with more effective outbreak control. Thus, in response to the Omicron variant, the management to restrict population movement should be used to control its spread quickly, especially in the case of community transmission occurs widely. Faster than is needed for non-Omicron variants, and decisive control measures should be imposed and dynamically adjusted in accordance with the evolving epidemic situation.

[Prevalence and risk factors of Giardia lamblia infections among colorectal cancer patients in Henan Province]

OBJECTIVE

To investigate the epidemiological characteristics and identify the risk factors of Giardia lamblia infections among patients with colorectal cancer in Henan Province.

METHODS

A cross-sectional study was performed for questionnaire surveys among colorectal cancer patients in Henan Cancer Hospital during the period from March to July, 2021. Patients' stool samples were collected, and the triosephosphate isomerase (tpi) gene of G. lamblia was amplified in stool samples using nested PCR assay to characterize the parasite genotype. Univariate analysis and multivariate logistic regression analyses were employed to identify the risk factors of G. lamblia infections among colorectal cancer patients.

RESULTS

A total of 307 colorectal cancer patients were investigated, including 176 males (57.3%) and 131 females (42.7%). PCR assay detected 8.1% [95% confidential interval (CI): (0.056, 0.117)] prevalence of G. lamblia infections among the study subjects, and there was no significant difference in the prevalence between men [9.1%, 95% CI: (0.057, 0.143)] and women [6.9%, 95% CI: (0.037, 0.125)] (χ² = 0.495, P = 0.482). In addition, there was no age-specific prevalence of G. lamblia infections among the participants (χ² = 1.534, P = 0.675). Multivariate logistic regression analysis identified use of septic tanks [odds ratio (OR) = 3.336, 95% CI: (1.201, 9.267)], daily use of well water [OR = 3.042, 95% CI: (1.093, 8.465)] and raising livestock [OR = 3.740, 95% CI: (1.154, 12.121)] as risk factors of G. lamblia infections among colorectal cancer patients, and the prevalence of abdominal pain was significantly greater in colorectal cancer patients with G. lamblia infections than in those without infections (P = 0.017). Among the 25 patients with G. lamblia infections, assemblage A was characterized in 24 (96.0%) cases and assemblage B in one case (4.0%).

CONCLUSIONS

The prevalence of G. lamblia is high among colorectal cancer patients in Henan Province, and assemblage A is the dominant genotype of G. lamblia. Use of septic tanks, daily use of well water and raising livestock are risk factors of G. lamblia infections among patients with colorectal cancer.

[Advances in the research of comorbidity of Blastocystis hominis infections and other diseases]

Blastocystis hominis is a common intestinal protozoan parasite. Most individuals with B. hominis infections have no apparent clinical symptoms; however, a few patients, notably those with co-infections or impaired immune system function may present abdominal pain, diarrhea, nausea, vomiting, and even death. This paper reviews the co-infections of B. hominis and other pathogens and comorbidity of B. hominis infections and other diseases, so as to provide insights into the management of B. hominis infections.

Efficacy of the combination of modern medicine and traditional Chinese medicine in pulmonary fibrosis arising as a sequelae in convalescent COVID-19 patients: a randomized multicenter trial

Background

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has led to a significant number of mortalities worldwide. COVID-19 poses a serious threat to human life. The clinical manifestations of COVID-19 are diverse and severe and 20% of infected patients are reported to be in a critical condition. A loss in lung function and pulmonary fibrosis are the main manifestations of patients with the severe form of the disease. The lung function is affected, even after recovery, thereby greatly affecting the psychology and well-being of patients, and significantly reducing their quality of life.

Methods

Participants must meet the following simultaneous inclusion criteria: over 18 years of age, should have recovered from severe or critical COVID-19 cases, should exhibit pulmonary fibrosis after recovery, and should exhibit Qi-Yin deficiency syndrome as indicated in the system of traditional Chinese medicine (TCM). The eligible candidates will be randomized into treatment or control groups. The treatment group will receive modern medicine (pirfenidone) plus TCM whereas the control group will be administered modern medicine plus TCM placebo. The lung function index will be continuously surveyed and recorded. By comparing the treatment effect between the two groups, the study intend to explore whether TCM can improve the effectiveness of modern medicine in patients with pulmonary fibrosis arising as a sequelae after SARS-CoV-2 infection.

Discussion

Pulmonary fibrosis is one of fatal sequelae for some severe or critical COVID-19 cases, some studies reveal that pirfenidone lead to a delay in the decline of forced expiratory vital capacity, thereby reducing the mortality partly. Additionally, although TCM has been proven to be efficacious in treating pulmonary fibrosis, its role in treating pulmonary fibrosis related COVID-19 has not been explored. Hence, a multicenter, parallel-group, randomized controlled, interventional, prospective clinical trial has been designed and will be conducted to determine if a new comprehensive treatment for pulmonary fibrosis related to COVID-19 is feasible and if it can improve the quality of life of patients.

Trial registration: This multicenter, parallel-group, randomized controlled, interventional, prospective trial was registered at the Chinese Clinical Trial Registry (ChiCTR2000033284) on 26th May 2020 (prospective registered).

Bioinformatic Prediction and Production of Four Recombinant Proteins from Different Developmental Stages of Trichinella spiralis and Testing of Their Diagnostic Sensitivity in Mice

Background:

Trichinellosis is a serious food-borne parasitic zoonosis, thus finding high quality antigens is the key to serodiagnosis of trichinosis. This article reports the characterization and sensitivity of four recombinant proteins expressed by four genes (Wn10, Zh68, T668, and Wm5) from different developmental stages of Trichinella spiralis for the diagnosis of trichinellosis in mice.

Methods:

This study was conducted in Jilin University and National Institute of Parasitic Diseases of Chinese Center for Disease Control and Prevention in 2017–2018. The structures and functions of the proteins encoded by four genes were predicted by bioinformatics analysis. The four genes were cloned and expressed, and the recombinant proteins were purified. Anti-Trichinella IgM and IgG antibodies in the sera of mice infected with T. spiralis from 1-45 d post-infection (dpi) were evaluated by ELISA.

Results:

The optimal antigen epitopes of four proteins (P1, P2, P3, and P4) encoded by the four genes from T- and B-cells were predicted, and four purified recombinant proteins (r-P1, r-P2, r-P3, and r-P4) were successfully produced. For IgM, the antibody levels detected by the four recombinant antigens were approximately equal to the cut-off value. Anti-Trichinella IgG antibodies were first detected by r-P1 at 8 dpi, followed by r-P2, r-P3, and r-P4 at 10 dpi, 14 dpi, and 16 dpi, respectively, and the antibody levels remained high until 45 dpi.

Conclusion:

The recombinant antigens r-P1, r-P2, r-P3, and r-P4 could be antigens that react with antibodies, they showed high sensitivity in the detection of anti-Trichinella IgG antibodies in mice. Among these proteins, r-P1 may be a candidate antigen for the detection of anti-Trichinella IgG antibodies in the early infection phase and exhibited the best sensitivity among the antigens.

Epidemiology of Blastocystis infection from 1990 to 2019 in China

Background

Blastocystis is ubiquitous presence in animals and humans worldwide and has a high level genetic diversity. The aim of this study was to conduct a summary of Blastocystis prevalence, subtypes (STs) in humans and animals in China and depict their distribution.

Methods

We searched for the articles related to epidemiology of Blastocystis in humans and animals throughout China which published from January 1, 1990, to July 31, 2019 in the following databases: PubMed, China National Knowledge Infrastructure (CNKI) and Wanfang database. The keywords were Blastocystis and one of the following ones: STs, subtypes, distribution, epidemiology, prevalence, infection, molecular, geographic, intestinal parasites, genetic diversity and characterization.

Results

In recent years, various molecular epidemiological studies have been carried out in some provinces/regions of China to identify subtypes of Blastocystis. Infants and young children, school students, hospitalized diarrhea patients, HIV/AIDS patients, tuberculosis patients, and cancer patients as respondents had been included. ST1–ST7 and ST12 were the main subtypes in Chinese population. Moreover, surveys of Blastocystis infection in animal were also conducted in some provinces of China. A variety of animals were investigated including pigs, cattle, sheep, yak, giant panda, and crested ibis (Nipponia nippon) with the main subtypes of ST1–ST8, ST10, ST12–ST14.

Conclusions

In recent years, some provinces/regions in China have conducted various molecular epidemiological studies to identify the Blastocystis subtypes. It is important to focus on new subtypes and mixed subtypes of infection, while increasing data on ribosomal alleles. We encourage the scientific community to start research on humans and surrounding animals (including domestic and wild animals) to better understand the possibility of Blastocystis transmission between humans and animals. We call for action among researchers studying intestinal parasitic diseases (Blastocystis), start drawing the subtype of Blastocystis and increase the subtype related to its clinical symptoms.

[Prevalence and risk factors of Blastocystis hominis infections among AIDS patients in Nanchang City]

OBJECTIVE

To investigate the prevalence and risk factors of Blastocystis hominis infections among AIDS patients in Nanchang City.

METHODS

A cross-sectional questionnaire survey was conducted among AIDS patients in Nanchang City during the period between May and September, 2016. B. hominis infection was detected in patients'stool samples using a PCR assay, and the CD4⁺ T cell count was measured in subjects'blood samples. In addition, the risk factors of B. hominis infection in AIDS patients were identified using univariate and multivariate logistic regression analyses.

RESULTS

A survey was conducted in Nanchang City from May to September 2016. A total of 505 AIDS patients were investigated, and the prevalence of B. hominis infection was 4.16%. Univariate analysis revealed that B. hominis infection correlated with the occupation (χ² = 8.595, P = 0.049), education level (χ² = 14.494, P = 0.001), type of daily drinking water (χ² = 10.750, P = 0.020), root of HIV infections (χ² = 8.755, P = 0.026) and receiving anti-HIV therapy (χ² = 23.083, P = 0.001) among AIDS patients, and multivariate logistic regression analysis identified daily direct drinking of tap water as a risk factor of B. hominis infections [odds ratio (OR) = 7.988, 95% confidential interval (CI): (1.160, 55.004)] and anti-HIV therapy as a protective factor of B. hominis infection [OR = 0.183, 95% CI: (0.049, 0.685)].

CONCLUSIONS

The prevalence of B. hominis is 4.16% among AIDS patients in Nanchang City. Daily direct drinking of tap water is a risk factor, and anti-HIV therapy is a protective factor of B. hominis infection among AIDS patients living in Nanchang City.

[Prevalence and risk factors of Blastocystis infections among primary school students in Jiangjin District, Chongqing City]

OBJECTIVE

To investigate the prevalence and risk factors of Blastocystis infections among primary school students in Jiangjin District, Chongqing City.

METHODS

A cross-sectional questionnaire survey was conducted among students sampled from a primary school in Jiangjin District, Chongqing City on April, 2018, and their stool samples were collected for microscopic examinations, in vitro culture and PCR assays to analyze the prevalence of Blastocystis infections and subtype of the parasite. In addition, the risk factors of Blastocystis infections among primary school students were identified using univariate analysis and multivariate logistic regression analysis.

RESULTS

A total of 466 primary students were surveyed, and the subjects had a mean age of (9.81±1.66) years and included 236 males (50.64%) and 230 females (49.36%). The prevalence of Blastocystis infections was 15.24% (71/466) among the study students, and there was no significance difference in the prevalence between male and fe- male students (16.52% vs. 13.91%; χ2 = 0.616, P = 0.433). In addition, there was a significant difference in the prevalence of Blastocystis infections among grade 1 (6.35%, 4/63), grade 2 (5.17%, 3/58), grade 3 (21.74%, 15/69), grade 4 (25.30%, 21/83), grade 5 (10.19%, 11/108) and grade 6 students (20.00%, 17/85) (χ2 = 15.410, P = 0.009). There were four Blastocystis subtypes characterized (ST1, ST3, ST6 and ST7), in which ST6 was the most common subtype (45.07%, 32/71), followed by ST3 (25.35%, 18/71). Multivariate logistic regression analysis revealed that minority ethnicity [odds ratio (OR) = 4.259, 95% confidential inter- val (CI) : (1.161, 15.621)] and low maternal education level (primary school and below) [OR = 9.038, 95% CI: (1.125, 72.642)] were identified as risk factors of Blastocystis infection among primary school students in Jiangjin District, Chongqing City.

CONCLUSIONS

There is a high prevalence of Blastocystis infections detected among primary school students in Jiangjin District, Chongqing City, and ST6 and ST3 are predominant subtypes. Minority ethnicity and low maternal education level (primary school and below) are risk factors for Blastocystis infections in primary school students.

[Progress of researches on Blastocystis infections in humans and animals in China]

Blastocystis is a unicellular, anaerobic, intestinal protozoan that infects humans and a variety of animals, which is widely prevalent across the world. Blastocystis infections have been detected in healthy populations, children, students, outpatients and inpatients, as well as diarrhea patients in China. High prevalence of Blastocystis infections has been reported in immunocompromised patients, and relatively high prevalence was seen in individuals living in Guangxi and Yunnan regions. Based on the small subunit ribosomal RNA (SSU rRNA) gene sequence, a total of 17 subtypes (ST1 to ST17) of Blastocystis have been characterized until now, among which ST1 to ST9 and ST12 infect humans and animals, and ST10 to ST17 only infect animals. In China, ST1 to ST3 are predominant human Blastocystis subtypes, and ST1/ST3, ST1/ST2 and ST2/ST3 mixed infections have been also identified. This review mainly describes the epidemiology and genotypes of Blastocystis in humans and animals in China.

[Prevalence and risk factors of Blastocystis hominis infection in inpatients in Jiangjin District, Chongqing City]

OBJECTIVE

To understand the prevalence and risk factors of Blastocystis hominis infection in inpatients in Jiangjin District, Chongqing City.

METHODS

A cross-sectional study was conducted in a community hospital in Jiangjin District, Chongqing City, and the inpatients were surveyed by questionnaires. After obtaining the informed consent from the inpatients or legal guardians, the stool and blood samples were collected and examined by microscopy and PCR from April 17 to May 1, 2018. The univariate analysis and logistic regression analysis were used to analyze the risk factors of the B. hominis infection.

RESULTS

A total of 198 hospitalized patients were investigated, and the infection rate of B. hominis was 10.61% (21/198), and the infection rate of the females (12.10%) was higher than that of the males (8.11%), but the difference was not statistically significant. The highest rate of infection was 19.23% in the age group of 10 to 20 years, followed by 17.74% in the age group of 60 years and above, and the lowest rate was 2.38% in the age group of 20 to 40 years. The difference in infection rates of B. hominis among the different age groups was statistically significant (P < 0.05). The infection rate of B. hominis in the people who used dry pail latrines was 33.30%, which was higher than that of the people who used water flush toilets (9.10%) (P < 0.05). The genotypes of B. hominis were ST1, ST3, ST6 and ST7, and ST6 and ST3 being the most predominant genotypes which accounted for 47.62% (10/21) and 38.10% (8/21) respectively, and among the infected males, the genotypes were only ST3 and ST6. The multiple logistic regression analysis showed that among the factors affecting B. hominis infection, only keeping pets was a risk factor [OR = 3.798, 95% CI (1.245, 11.581), P < 0.05].

CONCLUSIONS

A high prevalence of B. hominis infection is found in the inpatients in Jiangjin District, Chongqing City, the predominant genotypes are ST6 and ST3, and keeping pets may be one of the main risk factors.

[Epidemiological characteristics and risk factors of Blastocystis hominis infection among patients with HIV/AIDS in Fuyang City Anhui Province]

OBJECTIVE

To investigate the prevalence and risk factors of Blastocystis hominis infections among patients with HIV/AIDS in Fuyang City, Anhui Province.

METHODS

A cross-sectional study was conducted in Fuyang City, Anhui Province in 2016. The demographic and socioeconomic status, and the lifestyle and production style were collected using a questionnaire survey. B. hominis DNA was detected in subjects'stool samples using a PCR assay, and the CD4+ T lymphocyte count and HIV viral load were measured in the subjects' blood samples. The risk factors of B. hominis infections among patients with HIV/AIDS were identified using univariate and multivariate logistic regression analyses.

RESULTS

A total of 398 HIV/AIDS patients were enrolled in this study, with a mean age of 49.3 years, a mean body weight of 55.9 kg and a mean height of 164.4 cm. The prevalence of B. hominis infection was 6.78% in the study subjects, and no gender- (χ² = 1.589, P = 0.207), education level- (χ² =0.508, P = 0.776), marital status- (χ² = 0.419, P = 0.811) or occupation-specific prevalence (χ² = 2.744, P = 0.615) was detected. Among the patients with HIV/AIDS, there were no significant differences in the age (t = 0.370, P = 0.712), height (t = 1.587, P =0.113), body weight (t = 0.516, P = 0.606), CD4⁺ T lymphocyte count (t = 1.187, P = 0.230) or HIV viral load (t = 0.193, P =0.496) between B. hominis-infected and uninfected individuals. Dinking non-tap water [OR = 6.554, 95% CI: (1.876 to 22.903)] and keeping dogs [OR = 5.895, 95% CI: (2.017 to 17.225)] were identified as risk factors for B. hominis infection in patients with HIV/AIDS.

CONCLUSIONS

The prevalence of B. hominis infection is high in HIV/AIDS patients, and drinking non-tap water and keeping dogs are risk factors for B. hominis infection among HIV/AIDS patients.

Risk factors for Blastocystis infection in HIV/AIDS patients with highly active antiretroviral therapy in Southwest China

Background

Blastocystis is a widespread zoonotic protozoan of mammalian species, especially in HIV/AIDS individuals. The aim of this study was to analyze the prevalence and risk factors related with Blastocystis infection among HIV/AIDS patients in Southwest China.

Methods

The cross-sectional study was performed in 311 HIV/AIDS cases in Tengchong City, Yunnan Province from July 2016 to March 2017. For each subject, stool specimen was collected to detect the Blastocystis, and the blood sample was used to detect HIV virus load and CD4⁺ T cell count, in addition, structured questionnaire was used to collect the basic information and risk factors.

Findings

The result showed that the detection rate of Blastocystis was 3.86% (95% CI: 2.22–6.62) among HIV/AIDS patients. Both raising animal (OR = 12.93, 95% CI: 1.54–108.36) and drinking un-boiled water (OR = 8.17, 95% CI: 1.76–37.90) were risk factors for Blastocystis infection in HIV/AIDS individuals. In addition, the interaction of CD4⁺ T cell count and HIV virus load was also contribution to Blastocystis infection (P = 0.007).

Conclusions

A high prevalence of Blastocystis infection was found in HIV/AIDS patients in Tengchong. Poor hygienic habits, the interaction of HIV virus load and CD4⁺ T cell count were identified as main risk factors for infection. These results will help us to develop efficient control strategies to intervene with and prevent the occurrence of Blastocystis among HIV-infected individuals.

[Current status of pesticides against ticks]

Ticks can spread a variety of diseases and cause serious damage to animal husbandry. However, the existing insecticide and vaccine control methods have some disadvantages. In this paper, we review the research status of tick pesticides, including the chemical pesticides and non-chemical pesticides (Chinese herbal medicine, nanometer material, virus, fungus and bacterium pesticides), and analyze the disadvantages of the existing researches on pesticides against ticks, in order to provide a theoretical reference for establishing high-efficient and safety tick control methods.

Antibiotic resistance and molecular characterization of diarrheagenic Escherichia coli and non-typhoidal Salmonella strains isolated from infections in Southwest China

BACKGROUND

Bacterial diarrhea is one of the most common causes for medical consultations, mortality and morbidity in the world. Diarrheagenic Escherichia coli (DEC) and non-typhoidal Salmonella (NTS) are major intestinal pathogens in developing countries, and the indiscriminate use of antibiotics has greatly contributed to resistant strains. Hence, the aim of the present study is to identify the antimicrobial resistance patterns and the molecular characteristics of DEC and NTS in southwest, China.

METHODS

1121 diarrheal patients and 319 non-diarrheal subjects across all age groups were recruited from four sentinel hospitals from June 2014 to July 2015 in Kunming City, Yunnan Province. Each stool specimen was collected to detect DEC and NTS with standard microbiological and molecular methods. Antimicrobial resistance testing was performed with the Kirby-Bauer disk diffusion method, and the standards for antimicrobial susceptibility testing complied with the Clinical and Laboratory Standards Institute (CLSI). Molecular characterization of strains was carried out using pulsed-field gel electrophoresis (PFGE). A structured questionnaire was used to record basic epidemiological data (e.g. sex, age, residence, season, etc.). Data were analyzed using Chi-square or Fisher's exact test.

RESULTS

DEC was detected in 127 (11.33%) diarrhea cases and 9 (2.82%) non-diarrheal cases (χ² = 20.69, P < 0.001, OR = 4.36, 95% CI: 2.19-8.65), and the prevalence of NTS isolated from diarrhea cases was higher than that of non-diarrheal cases across all age groups (n = 42, 3.75%, n = 1, 0.31%, χ² = 10.10, P = 0.002, OR = 12.38, 95% CI: 1.70-90.29). The rates of resistance to ten antibiotics of DEC and NTS showed significant differences (χ ²  = 386.77, P < 0.001; χ² = 191.16, P < 0.001). The rates of resistance to Amoxicillin and Clavulafiate (AMC), Cephalothin (CEP), Gentamicin (GEN) and Sulfamethoxazole-Trimethoprim (SXT) of DEC isolated from diarrhea cases were higher than those of NTS isolated from diarrhea patients (37.01% vs 14.29%, χ² = 7.57, P = 0.006; 29.92% vs 11.90%, χ² = 5.40, P = 0.02; 37.01% vs 11.90%, χ² = 5.80, P = 0.016; 62.20% vs 26.19%, χ² = 16.44, P < 0.001; respectively). Ciprofloxacin (CIP) was the most sensitive antibiotic for DEC and NTS strains isolated from diarrhea cases. Resistance rates of DEC isolates from cases and controls to more than three kinds antimicrobials (multidrug resistance, MDR) showed no significant differences (81.10% vs 88.89%, P = 0.33). Pulsotype patterns of DEC strains were highly diverse; however, the pulsotype pattern of NTS strains was closely related to the serotype. The pattern of S. enteritidis was highly similar, but the S. enterica Typhimurium strain was discrete.

CONCLUSIONS

Antibiotic resistance of Enterobacteriaceae is of great concern. The societal effects of antibiotic use justify strict monitoring to combat increases in antimicrobial resistance. Molecular epidemiology and systematic epidemiological investigation can provide accurate evidence for tracking the infection source.

Case-control study of diarrheal disease etiology in individuals over 5 years in southwest China

Background

Acute diarrhea is one of the major public health problems worldwide. Most of studies on acute diarrhea have been made on infants aged below 5 years and few efforts have been made to identify the etiological agents of acute diarrhea in people over five, especially in China.

Methods

271 diarrhea cases and 149 healthy controls over 5 years were recruited from four participating hospitals between June 2014 and July 2015. Each stool specimen was collected to detect a series of enteric pathogens, involving five viruses (Rotavirus group A, RVA; Norovirus, NoV; Sapovirus, SaV; Astrovirus, As; and Adenovirus, Ad), seven bacteria (diarrheagenic Escherichia coli, DEC; non-typhoidal Salmonella, NTS; Shigella spp.; Vibrio cholera; Vibrio parahaemolyticus; Aeromonas spp.; and Plesiomonas spp.) and three protozoa (Cryptosporidium spp., Giardia lamblia, G. lamblia, and Blastocystis hominis, B. hominis). Standard microbiological and molecular methods were applied to detect these pathogens. Data was analyzed using Chi square, Fisher-exact tests and logistic regressions.

Results

The prevalence of at least one enteric pathogen was detected in 29.2% (79/271) acute diarrhea cases and in 12.1% (18/149) in healthy controls (p < 0.0001). Enteric viral infections (14.4%) were the most common in patients suffering from acute diarrhea, followed by bacteria (13.7%) and intestinal protozoa (4.8%). DEC (12.5%) was the most common causative agent in diarrhea cases, followed by NoV GII (10.0%), RVA (7.4%) and B. hominis (4.8%). The prevalence of co-infection was statistically higher (p = 0.0059) in the case group (7.7%) than in the healthy control (1.3%). RVA–NoV GII (3.0%) was the most common co-infection in symptomatic cases.

Conclusions

DEC was the most predominant pathogen in diarrhea cases, but it was largely overlooked because the lack of laboratory capacities. Because of the high prevalence of co-infections, it is recommended the urgent development of alternative laboratory methods to assess polymicrobial infections. Such methodological improvements will result in a better prevention and treatment strategies to control diarrhea illness in China.

Electronic supplementary material

The online version of this article (doi:10.1186/s13099-016-0141-1) contains supplementary material, which is available to authorized users.

Emergence of human caliciviruses among diarrhea cases in southwest China

BACKGROUND

Acute diarrhea is one of the most serious problems in global public health that causes considerable morbidity and mortality worldwide. Human caliciviruses (HuCV) including norovirus (NoV, genogroup GI and GII) and sapovirus (SaV), is a leading cause of acute sporadic diarrhea in individuals across all age groups. However, few studies had been conducted clarifying the characteristics of HuCV in diarrhea cases across all age groups in China. Our study was aimed at assessing the HuCV-related diarrhea burden and NoV genotypes distribution in southwest China.

METHODS

The study was conducted in four hospitals in Kunming city, Yunnan province, from June 2014 to July 2015. Stool specimens were collected from 1,121 diarrhea cases and 319 healthy controls in outpatient departments. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect NoV (GI, GII) and SaV. Sequencing was applied to confirm the three viral infections and phylogenetic analysis was performed to determine their genotypes. A structured questionnaire was used to record the demographic information and clinical symptoms of subjects.

RESULTS

HuCV was detected at an 11.0 % infection rate in 1,121 diarrhea cases and at 3.4 % rate in 319 non-diarrhea subjects (p < 0.0001, OR = 3.5, 95 % CI 1.8-6.5). The prevalence of the NoV genogroup GII and genotype GII.4 in diarrhea cases was significantly higher than that found in healthy controls (p < 0.0001, p = 0.018, respectively). NoV GII (n = 118, 10.5 %) was the most common HuCV subtype in diarrhea cases, followed by SaV (n = 3, 0.3 %) and NoV GI (n = 2, 0.2 %). Of 118 NoV GII strains isolated from diarrhea patients. GII.4 (n = 55, 46.6 %) was the predominant strain, followed by GII.3 (n = 28, 23.7 %), GII.12 (n = 25, 21.2 %), GII.17 (n = 8, 6.8 %), and GII.5 (n = 2, 1.7 %). Of the 55 GII.4 strains, the GII.4 Sydney 2012 variant had absolutely predominant prevalence (n = 52, 94.5 %), followed by the NoV GII.4-2006b variant (n = 3, 5.5 %). The GII.4 Orleans 2009 variant was not found in diarrhea cases of the study.

CONCLUSIONS

NoV GII was the major genogroup and GII.4 was the most predominant strain detected in diarrhea patients. The GII.17 is an emergent variant in sporadic diarrhea and might become the predominant strain in diarrhea cases in the near future. Rapid, accurate detection kits need to be developed to help us find and treat NoV-associated diarrhea in clinical settings in a timely manner.

Impact of co-infections with enteric pathogens on children suffering from acute diarrhea in southwest China

Background

Acute diarrhea is a global health problem, resulting in high morbidity and mortality in children. It has been suggested that enteric pathogen co-infections play an important role in gastroenteritis, but most research efforts have only focused on a small range of species belonging to a few pathogen groups. This study aimed to assess the impact of co-infections with a broad range of enteric pathogens on children aged below five years who suffer from acute diarrhea in southwest China.

Method

A total of 1020 subjects (850 diarrhea cases and 170 healthy controls) were selected from four sentinel hospitals in Kunming, Yunnan province, southwest China, from June 2014 to July 2015. Stool specimens were collected to detect five virus (rotavirus group A, RVA; norovirus, NoV; Sapovirus, SaV; astrovirus, As; and adenovirus, Ad), seven bacterial (diarrheagenic Escherichia coli, DEC; non-typhoidal Salmonella, NTS; Shigella spp.; Vibrio cholera; Vibrio parahaemolyticus; Aeromonas spp.; and Plesiomonas spp.), and three protozoan (Cryptosporidium spp., Giardia lamblia, and Blastocystis hominis, B. hominis) species using standard microbiologic and molecular methods. Data were analyzed using the partial least square regression technique and chi-square test.

Results

At least one enteric pathogen was detected in 46.7 % (n = 397) of acute gastroenteritis cases and 13.5 % (n = 23) of healthy controls (χ² = 64.4, P < 0.05). Single infection with RVA was associated with acute diarrhea (26.5 % vs. 5.8 %, P < 0.05). The prevalence of a single infection with B. hominis in diarrhea cases was higher than in healthy controls (3.1 % vs. 0.5 %, OR = 4.7, 95 % CI: 1.01–112.0). Single infection with NoV GII was not associated with diarrhea (4.4 % vs. 3.5 %, OR = 1.2, 95 % CI: 0.5–3.3). Single infections with bacterial species were not observed. The prevalence of co-infections with two enteric pathogens in diarrhea cases was higher than in asymptomatic children (20.1 % vs. 5.3 %, P < 0.05). RVA-NoV GII was the most common co-infection in symptomatic children (4.4 %), with it aggravating the severity of diarrhea.

Conclusions

Although it is clear that RVA has an overwhelming impact on diarrhea illnesses in children, co-infection with other enteric pathogens appears to also aggravate diarrhea severity. These findings should serve as evidence for public health services when planning and developing intervention programs.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-016-0157-2) contains supplementary material, which is available to authorized users.

Field comparison of circulating antibody assays versus circulating antigen assays for the detection of schistosomiasis japonica in endemic areas of China

BACKGROUND

Schistosomiasis remains a serious public health problem in affected countries, and routine, highly sensitive and cost-effective diagnostic methods are lacking. We evaluated two immunodiagnostic techniques for the detection of Schistosoma japonicum infections: circulating antibody and circulating antigen assays.

METHODS

A total of 1864 individuals (between 6 and 72 years old) residing in five administrative villages in Hubei province were screened by serum examination with an indirect hemagglutination assay (IHA). The positive individuals (titer ≥20 in IHA) were reconfirmed by stool examination with the Kato-Katz method (three slides from a single stool specimen). Samples of good serum quality and a volume above 0.5 ml were selected for further testing with two immunodiagnostic antibody (DDIA and ELISA) and two antigen (ELISA) assays.

RESULTS

The average antibody positive rate in the five villages was 12.7%, while the average parasitological prevalence was 1.50%; 25 of the 28 egg-positive samples were also circulating antigen-positive. Significant differences were observed between the prevalence according to the Kato-Katz method and all three immunodiagnostic antibody assays (P-value <0.0001). Similar differences were observed between the Kato-Katz method and the two immunodiagnostic antigen assays (P-value <0.0001) and between the antigen and antibody assays (P-value <0.0001).

CONCLUSION

Both circulating antibody and circulating antigen assays had acceptable performance characteristics. Immunodiagnostic techniques to detect circulating antigens have potential to be deployed for schistosomiasis japonica screening in the endemic areas.

[Establishment of A1E3 and B1C4 monoclonal antibody-based ELISA for detecting circulating antigen of Schistosoma japonicum and its preliminary application]

OBJECTIVE

To establish A1E3 and B1C4 monoclonal antibody-based ELISA for detecting circulating antigen of Schistosoma japonicum and explore its application value in the field.

METHODS

The characteristics of A1E3 and B1C4 monoclonal antibodies were analyzed by SDS-PAGE and Western blotting. The SEA-based ELISA was used to evaluate the titers of A1E3 and B1C4. The orthogonal test was used to determine the best concentration of coating antibody B1C4 and optimal working concentration of A1E3-HRP. Under the optimal conditions, the serum samples of 20 acute schistosomiasis cases, 46 chronic schistosomiasis cases, and 20 control sera were tested to evaluate its detection sensitivity and specificity. Seventy-two antibody positive serum samples from Jiangling County of Hubei Province were detected and compared to a commercially available ELISA kit, to evaluate the detection effects of this method.

RESULTS

The results of SDS-PAGE demonstrated that the purified A1E3 and B1C4 contained a clear heavy chain with molecular weight of 88,000 and 52,000 respectively and had the same light chain with molecular weight of 20,000; while Western blotting demonstrated that A1E3 and B1C4 could be recognized by SEA and serum samples of acute schistosomiasis cases. The SEA-based ELISA demonstrated the titers of B1C4 and A1E3 were 1:10(5) and 1:30,000, respectively. The serum samples from all the acute cases and 86.9% of the chronic cases showed a positive reaction. All of the control sera from healthy persons gave a negative response. The positive rates of the double monoclonal antibody ELISA and commercial ELISA for detecting the circulating antigen were 45.8% and 43.1% respectively, and there was no significant difference between the results of the two methods.

CONCLUSION

A1E3 and B1C4 monoclonal antibody-based ELISA is established successfully. It exhibits a high sensitivity and specificity in detecting circulating antigen of Schistosoma japonicum.

Intestinal parasite co-infection among pulmonary tuberculosis cases without human immunodeficiency virus infection in a rural county in China

Epidemiologic studies of co-infection with tuberculosis (TB) and intestinal parasites in humans have not been extensively investigated in China. A cross-section study was conducted in a rural county of Henan Province, China. Pulmonary TB (PTB) case-patients receiving treatment for infection with Mycobacterium tuberculosis and healthy controls matched for geographic area, age, and sex were surveyed by using questionnaires. Fecal and blood specimens were collected for detection of intestinal parasites, routine blood examination, and infection with human immunodeficiency virus. The chi-square test was used for univariate analysis and multivariate logistic regression models were used to adjust for potential confounding factors. A total of 369 persons with PTB and 366 healthy controls were included; all participants were negative for human immunodeficiency virus. The overall prevalence of intestinal parasites in persons with PTB was 14.9%, including intestinal protozoa (7.9%) and helminthes (7.6%). The infection spectrum of intestinal parasites was Entamoeba spp. (1.4%), Blastocystis hominis (6.2%), Trichomonas hominis (0.3%), Clonorchis sinensis (0.3%), Ascaris lumbricoides (0.5%), Trichuris trichiura (2.2%), and hookworm (4.6%). The prevalence of intestinal parasites showed no significant difference between persons with PTB and healthy controls after adjusting for potential confounding factors. There was no factor that affected infection rates for intestinal parasites between the two groups. Infection with intestinal parasites of persons with PTB was associated with female sex (adjusted odds ratio [AOR] = 2.05, 95% confidence interval [CI] = 1.01-4.17), body mass index ≤ 19 (AOR = 3.02, 95% CI = 1.47-6.20), and anemia (AOR = 2.43, 95% CI = 1.17-5.03). Infection of healthy controls was only associated with an annual labor time in farmlands > 2 months (AOR = 4.50, 95% CI = 2.03-10.00). In addition, there was no significant trend between rates of infection with intestinal parasites and duration of receiving treatment for infection with M. tuberculosis in persons with PTB. The prevalence of intestinal parasites was not higher in persons with PTB, and there was no evidence that PTB increased susceptibility to intestinal parasites in this study. However, for patients with PTB, women and patients with comorbidities were more likely to be infected with intestinal parasites.

HIV and intestinal parasite co-infections among a Chinese population: an immunological profile

BACKGROUND

Parasite infections often result in a switch of the human body's predominant immune reaction from T-helper 1 (Th1)-type to Th2-type. Hence, parasite infections are widely expected to accelerate the progression of human immunodeficiency virus (HIV) infections to acquired immunodeficiency syndrome (AIDS). In the People's Republic of China, both parasitic diseases and AIDS are epidemic in certain rural areas, and co-infections are relatively common. However, no population-based studies have yet investigated the frequency of HIV and parasite co-infections, and its effects on immune responses. We studied (1) the immune status of an HIV-infected population, and (2) the effect of co-infection of HIV and intestinal parasites on selected parameters of the human immune system.

METHODS

A total of 309 HIV-infected individuals were recruited and compared to an age-matched and sex-matched control group of 315 local HIV-negative individuals. Questionnaires were administered to all participants to obtain information on sociodemographic characteristics, sanitation habits, family income, and recent clinical manifestations. Two consecutive stool samples and 10 ml samples of venous blood were also collected from each individual for the diagnosis of parasite infections and quantitative measurements of selected cytokines and CD4+ T-lymphocytes, respectively.

RESULTS

During the study period, 79 HIV-infected individuals were not under highly active antiretroviral therapy (HAART) and were thus included in our analysis; the prevalence of intestinal helminth infections was 6.3% and that of protozoa was 22.8%. The most common protozoan infections were Blastocystis hominis (B. hominis) (13.9%) and Cryptosporidium spp. (10.1%). The prevalence of Cryptosporidium spp. in HIV-infected individuals was significantly higher than that in HIV negative individuals (P < 0.05). Compared to the non-co-infected population, no significant difference was found for any of the measured immunological indicators (P > 0.05). However, the following trends were observed: IFN-γ levels were lower, but the IL-4 level was higher, in the population co-infected with HIV and helminths. In the population co-infected with HIV and B. hominis, the IL-2 level was higher. The population co-infected with HIV and Cryptosporidium spp. had markedly lower CD4+ T-lymphocyte counts.

CONCLUSION

According to the immunologic profile, co-infection with helminths is disadvantageous to HIV-infected individuals. It was associated with a shift in the Th1/Th2 balance in the same direction as that caused by the virus itself, which might indicate an acceleration of the progress from an HIV infection to AIDS. Co-infection with Cryptosporidium spp. was not associated with a significant change in immune factors but co-infection with Cryptosporidium spp. was associated with a reduced level of CD4 + T-lymphocytes, confirming the opportunistic nature of such infections. Co-infection with B. hominis, on the other hand, was associated with an antagonistic shift in the immunological profile compared to an HIV infection.

Water-related parasitic diseases in China

Water-related parasitic diseases are directly dependent on water bodies for their spread or as a habitat for indispensable intermediate or final hosts. Along with socioeconomic development and improvement of sanitation, overall prevalence is declining in the China. However, the heterogeneity in economic development and the inequity of access to public services result in considerable burden due to parasitic diseases in certain areas and populations across the country. In this review, we demonstrated three aspects of ten major water-related parasitic diseases, i.e., the biology and pathogenicity, epidemiology and recent advances in research in China. General measures for diseases control and special control strategies are summarized.

[Survey on Blastocystis hominis infection in HIV positive individuals in Fuyang City, Anhui Province]

OBJECTIVE

To understand the epidemiological characteristics of co-infection of HIV and Blastocystis hominis and its risk factors.

METHODS

A total of 309 people with HIV positive in the development zone of Fuyang City were recruited, and the face to face questionnaires were conducted to collect the information of behavioral characteristics and sociodemographic data of the participants. Meanwhile, the samples of stool and blood were collected to test B. hominis, cytokines and CD4+/CD8+ T-lymphocyte. The influencing factors of co-infection of HIV and Blastocystis hominis were analyzed by the single factor analysis and Logistic regression analysis.

RESULTS

Among the 309 people involved, 302 accepted feces examinations, 286 accepted the questionnaire investigation, and 263 accepted both of them. The infection rate of B. hominis was 17.11%, that of the female was 21.90%, which was significantly higher than that of the male (11.90%) (P < 0.05). The results from the multivariate Logistic regression model showed that good nutrition was significantly associated with the co-infection of HIV and B. hominis (OR = 0.263, 95% CI: 0.073, 0.945).

CONCLUSIONS

The infection rate of B. hominis is high in people with HIV positive, and the nutrition situation of individuals may be one of the important risk factors associated with co-infection.

[Survey on co-infection with HIV and intestinal parasites in high prevalence areas of HIV/AIDS, China]

OBJECTIVE

To understand the co-infection status of HIV and intestinal parasites in a HIV/AIDS highly endemic area in China.

METHODS

A cross-sectional survey was carried out in two villages in Fuyang City, Anhui Province, and the infection status of HIV and intestinal parasites were investigated by blood and fecal examinations.

RESULTS

A total 769 individuals were enrolled in the investigation, and 720 of whom were participated in stool examinations for intestinal parasite infections. The infection rates of parasites were as follows: 0.56% for Ascaris lumbricoides, 4.03% for Hookworm, 0.28% for Trichuris trichiura, 0.42% for Clonorchis sinensis, 21.39% for Blastocystis hominis, 3.89% for Giardia lamblia, 1.67% for Entamoeba spp., 4.44% for Cryptosporidium spp.. The overall infection rate of intestinal worms and protozoan were 4.72% and 24.31%, respectively. The prevalence rate of anemia was 34.68%. The prevalence rate of HIV was 8.10%. The co-infection rate of HIV and intestinal helminthes was 2.17%, and that of HIV and intestinal protozoan was 28.26%, of which the co-infection rate of Blastocystis hominis and HIV were 19.57%. There was a significant difference between the infection rates of Cryptosporidium spp. in the HIV-positive group (13.04%) and HIV-negative group (4.70%) (P <0.05).

CONCLUSIONS

The infection rate of intestinal protozoan is higher than that of intestinal helminthes in local residents. The HIV-positive population is more susceptible to the infection of Cryptosporidium spp.

Co-infection of HIV and intestinal parasites in rural area of China

BACKGROUND

Intestinal parasite infections (IPIs) are among the most significant causes of illness and disease of socially and economically disadvantaged populations in developing countries, including rural areas of the People's Republic of China. With the spread of the human immunodeficiency virus (HIV) among rural Chinese populations, there is ample scope for co-infections and there have been increasing fears about their effects. However, hardly any relevant epidemiological studies have been carried out in the country. The aim of the present survey was to assess the IPI infection status among a representative sample of HIV-positive Chinese in rural Anhui province, and compare the findings with those from a cohort of non-infected individuals.

METHODS

A case control study was carried out in a rural village of Fuyang, Anhui province, China. Stool samples of all participants were examined for the presence of intestinal parasites. Blood examination was performed for the HIV infection detection and anemia test. A questionnaire was administered to all study participants.

RESULTS

A total of 302 HIV positive and 303 HIV negative individuals provided one stool sample for examination. The overall IPI prevalence of intestinal helminth infections among HIV positives was 4.3% (13/302) while it was 5.6% (17/303) among HIV negatives, a non-significant difference. The prevalence of protozoa infections among HIV positives was 23.2% while the rate was 25.8% among HIV negatives. The species-specific prevalences among HIV positives were as follows: 3.6% for hookworm, 0.7% for Trichuris trichiura, zero for Ascaris lumbricoides, 0.3% for Clonorchis sinensis, 1.3% for Giardia intestinalis, 16.2% for Blastocystis hominis, 1.7% for Entamoeba spp. and 8.3% for Cryptosporidium spp.. Cryptosporidium spp. infections were significantly more prevalent among HIV positives (8.3%) compared to the HIV negative group (3.0%; P < 0.05). Among people infected with HIV, Cryptosporidium spp. was significantly more prevalent among males (12.6%) than females (4.4%; P < 0.05). According to multivariate logistic regression, the factors significantly associated with parasite infections of the people who were HIV positive included sex (male: OR = 6.70, 95% CI: 2.030, 22.114), younger age (less than 42 years old: OR = 4.148, 95% CI: 1.348, 12.761), and poor personal hygiene habits (OR = 0.324, 95% CI: 0.105, 0.994).

CONCLUSIONS

HIV positive individuals are more susceptible to co-infections with Cryptosporidium spp. than HIV negative people, particularly younger males with poor personal hygiene habits, indicating a need for targeted hygiene promotion, IPI surveillance and treatment.

Chicken egg yolk antibodies (IgY) for detecting circulating antigens of Schistosoma japonicum

BACKGROUND

IgY isolated from egg yolk has been widely used in immunodiagnostic tests, including tests to detect circulating antigen (soluble egg antigen or SEA) of Schistosoma japonicum.

RESULTS

A sandwich ELISA was established using a combination of anti-S. japonicum SEA-IgY polyclonal antibodies and IgM monoclonal antibodies. To explore sensitivity and specificity of the sandwich ELISA, serum samples from 43 patients infected with S. japonicum were tested. All acute cases and 91.3% of the chronic cases showed a positive reaction. Only 5% of the control sera from healthy persons gave a positive response. Cross-reactions with antibodies to nine other parasites were rare.

CONCLUSION

The developed immunoassay is reasonably sensitive and specific. It could be used for field research and treatment efficacy assessments.

[Cross-section study on co-infection of HIV and Cryptosporidium]

OBJECTIVE

To investigate the co-infection status of HIV and Cryptosporidium, and explore the influencing factors associated with the co-infection.

METHODS

A total of 309 people with HIV positive in Fuyang City of Anhui Province were recruited and their fecal and blood samples were collected for examinations of Cryptosporidium spp. infection and the levels of hemoglobin, cytokines and CD4+/CD8+ T-lymphocytes. Meanwhile, the questionnaire survey was conducted.

RESULTS

Among 302 people involved in fecal examinations, the infection rate of Cryptosporidium spp. was 8.28%, and the difference between infection rates of the male (13.49%) and the female (2.92%) was statistically significant (P < 0.05). The multivariate logistic regression model showed that 4 factors were significantly associated with the coinfection of HIV and Cryptosporidium spp, including male (OR = 6.700, 95% CI: 2.030, 22.114), younger than 42 years old (OR = 4.148, 95% CI: 1.348, 12.761), level of IL-2 below 77 pg/ml (OR = 0.226, 95%CI: 0.076, 0.674) and personal hygiene habits (OR = 0.324, 95% CI: 0.105, 0.994).

CONCLUSION

The co-infection rate of Cryptosporidium spp. and HIV is high, the key targets of control are the people who are male, younger than 42 years old, with high level of IL2 and poor personal hygiene habits.

[Efficacy of tribendimdine in treatment of hookworm infection]

OBJECTIVE

To study the efficacy of tribendimdine in the treatment of hookworm infection.

METHODS

Forty-seven cases of hookworm infection detected in a cross-sectional study were selected and randomly divided into two groups, one was experimental group (23 cases) treated with tribendimdine and the other was control group (24 cases) treated with albendazole. The negative conversion rates and the incidence rates of adverse effects in the two groups were observed and compared.

RESULTS

The negative conversion rates and the incidence rates of adverse effects of the two groups were 95.65% and 95.83%, 8.70% and 8.33%, respectively, there were no statistical differences (both P values > 0.05).

CONCLUSION

The efficacy of tribendimdine in the treatment of hookworm infection is similar to albendazole.

[Current situation and developmental trend of anthelmintics by bibliometrics]

OBJECTIVE

To understand the current situation and developmental trend of anthelmintics in English journals through a bibliometric analysis.

METHODS

The literature was searched in Pubmed Database (1997-2007) using the following key words: "drug therapy", "anthelmintics", "humans", "pharmacology", and "parasitology". Access Database was constructed by relative literature through proper data admission method. The relative articles in the database were sorted by different categories, such as "research categories", "publishing year" and "research drug". Data were analyzed by using SPSS software.

RESULTS

The annual number of anthelmintics articles increased steadily from year 1997 to 2007. The average number of annual increase was about 6. The major research category was applied research. The major diseases were schistosomiasis, filariasis, ascariasis, echinococcosis and hookworm disease. The number of articles on schistosomiasis was higher than that of other four diseases (P<0.05). The major drugs involved were albendazole, praziquantel, mebendazole, ivermectin and diethylcarbamazine. Articles on the anthelmintics were published mostly in medical journals. From the total database, articles published at the top five journals occupied 5.52%, 4.39%, 3.76%, 3.26%, and 3.26%, respectively.

CONCLUSION

Increasingly importance has been attached to anthelmintics in the last decade. Meanwhile, the researchers focused on a few anthelmintics, and it is inevitable to develop new drugs.

HIV/AIDS, parasites and co-infections: publication patterns in China

Background

Since its discovery, HIV/AIDS has arguably captured more attention among the Chinese biomedical research community than most other infectious diseases. Traditional parasitic diseases, on the other hand, are perceived as being increasingly neglected. However, it has long been recognized that interactions between HIV and other infective agents, including parasites, influence the health status of people living with HIV/AIDS. This study aimed at systematically reviewing the Chinese scientific literature on HIV/AIDS and parasites between 1986 and 2006 in order to substantiate or refute these claims, and to highlight neglected research areas.

Results

Searching the three largest Chinese scientific literature databases, in the China National Knowledge Infrastructure (CNKI) a total of 24,511 citations dealing with HIV/AIDS and 15,398 parasite-specific publications were identified. Wanfang Data and VIP Information (VIP) contained 15,925 and 13,873 entries dealing with HIV/AIDS respectively, while 12,043 and 7,068 hits were scored when searching for parasitological references. The number of publications dealing with HIV/AIDS in China increased exponentially from 6 in 1986 to 3,372 in 2006 whereas the publication activity in the field of parasitology was more erratic and lately started to decline. Epidemiology was the most-reported field of endeavor, accounting for 26.0% and 24.6% of the HIV/AIDS and parasitological literature, respectively, while publications dealing with health education only represented 2.9% and 0.7% of all publications, respectively. The total number of Chinese articles focusing on HIV/AIDS and parasite co-infection was 650, with large year-on-year differences in publication numbers. The single-most frequently studied system was HIV-Pneumocystis carinii co-infection.

Conclusion

The present study revealed that in China, the fields of parasitic diseases, especially opportunistic parasitic infections linked with HIV/AIDS, is increasingly neglected. This suggests a need to enhance research in the field of opportunistic parasitic infections and parasitology in general.

[The neglected intestinal parasite co-infection with AIDS]

In order to increase the recognition of intestinal parasitic infections in AIDS, this article reviews the common intestinal parasites co-infected in HIV carriers and AIDS patients, namely, Cryptosporidium spp., microsporidia, Giardia lamblia, and Strongyloides stercoralis, referring to aetiology, epidemiology, clinical features, diagnosis and prevention.

Harnessing the wealth of Chinese scientific literature: schistosomiasis research and control in China

The economy of China continues to boom and so have its biomedical research and related publishing activities. Several so-called neglected tropical diseases that are most common in the developing world are still rampant or even emerging in some parts of China. The purpose of this article is to document the significant research potential from the Chinese biomedical bibliographic databases. The research contributions from China in the epidemiology and control of schistosomiasis provide an excellent illustration. We searched two widely used databases, namely China National Knowledge Infrastructure (CNKI) and VIP Information (VIP). Employing the keyword "Schistosoma" () and covering the period 1990–2006, we obtained 10,244 hits in the CNKI database and 5,975 in VIP. We examined 10 Chinese biomedical journals that published the highest number of original research articles on schistosomiasis for issues including languages and open access. Although most of the journals are published in Chinese, English abstracts are usually available. Open access to full articles was available in China Tropical Medicine in 2005/2006 and is granted by the Chinese Journal of Parasitology and Parasitic Diseases since 2003; none of the other journals examined offered open access. We reviewed (i) the discovery and development of antischistosomal drugs, (ii) the progress made with molluscicides and (iii) environmental management for schistosomiasis control in China over the past 20 years. In conclusion, significant research is published in the Chinese literature, which is relevant for local control measures and global scientific knowledge. Open access should be encouraged and language barriers removed so the wealth of Chinese research can be more fully appreciated by the scientific community.

[Incidence rates of human immunodeficiency virus and syphilis as well as the rate of retention in a 6-month follow-up study of female sex workers in areas with heavy drug use in Xichang of Sichuan province, China]

OBJECTIVE

To investigate the human immunodeficiency virus (HIV) and syphilis incidence rates as well as the retention rate in a cohort with 6-month follow-up study among female sex workers (FSWs).

METHODS

From December, 2004, to January, 2005, a community-based baseline survey was conducted to recruit 343 FSWs for a prospective cohort study in Xichang county of Sichuan province, China. Follow-up visits were conducted at 6 months to analyze risk factors associated with cohort retention for subjects' baseline sociodemographic and sexual behavioral characteristics. Blood specimens were also collected to test antibodies against HIV and syphilis.

RESULTS

During the 6-month follow-up period, HIV and syphilis incidence appeared to be 1.00 per 100 person-years and 6.23 per 100 person-years, respectively. The rate of retention in the cohort was 53.6% (184/343). Results from multivariate logistic regression model showed that factors were significantly associated with cohort retention including people with minority ethnic background (OR = 0.36; 95% CI: 0.18-0.74), people having participated in AIDS prevention program (OR = 1.83; 95% CI: 1.17-2.86) or being clients in the last 6 months > or = 50 (OR = 1.75; 95% CI: 1.11-2.77) and having changed living/working place (OR = 0.56; 95% CI: 0.33-0.94).

CONCLUSION

The results of this study showed that the syphilis incidence and unprotected sex behavior were high among local FSWs. People belonged to Han nationality, having participated in AIDS prevention program and having a steady living/working place were associated with cohort retention at 6-month follow-up study among FSWs, respectively.