Prevalence and associated factors of Treponema pallidum infection in a rural area of southwestern China

Social and individual vulnerability factors associated with syphilis among populations living on islands in the Brazilian Amazon

BACKGROUND

The repercussions of the syphilis epidemic differ according to populations. Identifying and acknowledging the differences and specificities of populations is fundamental in the design and implementation of policies aimed at assisting the groups most vulnerable to syphilis.

OBJECTIVE

To estimate the prevalence of antibodies against Treponema pallidum and associated vulnerability factors among riverside populations of a capital city in the Brazilian Amazon.

METHODS

Cross-sectional study was conducted among residents of the periurban islands in Belém, northern Brazil, from August 2020 to January 2021. The inclusion criterion was being a resident of the riverside communities of the Combú Environmental Protection Area, aged 18 years or over. The participants responded to questionnaire and were tested for syphilis using rapid test. Data were analyzed using multiple logistic regression by Minitab version 20® software.

RESULTS

Overall, a total of 325 riverine were included. Age varied from 18 to 91 years (average 40 years). Prevalence of markers for syphilis was 5.9% (95% CI: 3.3%-8.4%). The multiple regression showed that as age increases, the chances of having syphilis also increase (p = 0.001; aOR: 1.04) and riverside dwellers with more than one sexual partner in the last 6 months had more than four chances of having syphilis compared to people who had only one sexual partner (p = 0.007; aOR: 4.20).

CONCLUSION

Syphilis circulates among traditional populations in the Amazon and is associated with factors of social and individual vulnerability.

Spatial Heterogeneity and Its Influencing Factors of Syphilis in Ningxia, Northwest China, from 2004 to 2017: A Spatial Analysis

Syphilis remains a growing and resurging infectious disease in China. However, exploring the influence of environmental factors on the spatiotemporal distribution of syphilis remains under explore. This study aims to analyze the spatiotemporal distribution characteristics of syphilis in Ningxia, Northwest China, and its potential environmental influencing factors. Based on the standardized incidence ratio of syphilis for 22 administrative areas in Ningxia from 2004 to 2017, spatiotemporal autocorrelation and scan analyses were employed to analyze the spatial and temporal distribution characteristics of syphilis incidence, while a fixed-effect spatial panel regression model identified the potential factors affecting syphilis incidence. Syphilis incidence increased from 3.78/100,000 in 2004 to 54.69/100,000 in 2017 with significant spatial clustering in 2007 and 2009-2013. The "high-high" and "low-low" clusters were mainly distributed in northern and southern Ningxia, respectively. The spatial error panel model demonstrated that the syphilis incidence may be positively correlated with the per capita GDP and tertiary industry GDP and negatively correlated with the number of health facilities and healthcare personnel. Sex ratio and meteorological factors were not significantly associated with syphilis incidence. These results show that the syphilis incidence in Ningxia is still increasing and has significant spatial distribution differences and clustering. Socio-economic and health-resource factors could affect the incidence; therefore, strengthening syphilis surveillance of migrants in the economically developed region and allocating health resources to economically underdeveloped areas may effectively help prevent and control syphilis outbreaks in high-risk cluster areas of Ningxia.

Prevalence of Treponema Pallidum Antibody among Volunteer Blood Donors in China

Background

Infection with syphilis is still a major public health problem. The precise data for syphilis seroprevalence in the populations will help to develop a strategy for prevention and treatment of it. However, the data for syphilis prevalence in continuous years among volunteer blood donors in China is rare.

Methods

A retrospective study for Treponema pallidum (TP) antibody in blood donors was conducted from January 2010 to December 2019 at the Blood Center of Zhejiang Province, China. TP antibody was detected with two different reagents using enzyme-linked immunosorbent assay and the only sample which was reactive in the two reagents was defined as seropositive.

Results

A total of 992,646 volunteer blood donors were analyzed and the positive rate of TP antibody in the blood donors was 0.43%. From 2010 to 2019, the positive rates of TP antibody were 0.53%, 0.51%, 0.51%, 0.43%, 0.36%, 0.18%, 0.11%, 0.12%, 0.11%, and 0.10%, respectively. The positive rates of TP antibody were significantly different among blood donor age group (p < 0.001), with the highest positive rate in 45–54-years-old group (0.93%). The positive rates of TP antibody in male and female blood donors were 0.44% and 0.41%, respectively. The positive rate was 0.57% among the first-time blood donors, which was significantly higher than that of the repeat blood donors (0.17%). The positive rate of TP antibody in blood donors decreased gradually with the increase of educational level.

Conclusion

The syphilis seroprevalence is low in the blood donors of the Hangzhou area, and the positive rate of blood donors is associated with age, educational level, and times of blood donation. Increasing the number of repeat blood donations is helpful to improve blood safety.

Systematic Review of Hepatitis C Virus Prevalence in the WHO Western Pacific Region

BACKGROUND

This review aimed to identify hepatitis C virus (HCV) prevalence estimates among the general population and six key populations (people who inject drugs, men who have sex with men, sex workers, prisoners/detainees, Indigenous people, and migrants) in the World Health Organization Western Pacific Region (WHO WPR).

METHODS

Original research articles published between 2016 and 2020 were identified from bibliographic databases. Publications were retrieved, replicas removed, and abstracts screened. Retained full texts were assessed and excluded if inclusion criteria were not met. Methodological quality was assessed using the Johanna Briggs Institute critical appraisal checklist for prevalence data. Data on HCV exposure and active infection were extracted and aggregated and forest plots generated for each population by country.

RESULTS

There were no HCV prevalence estimates in any population for more than half of WPR countries and territories. Among the 76 estimates, 97% presented prevalence of exposure and 33% prevalence of active infection. General population viraemic prevalence was 1% or less, except in Mongolia. Results confirm the endemic nature of HCV among people who inject drugs, with estimates of exposure ranging from 30% in Cambodia to 76% in Hong Kong.

CONCLUSIONS

Countries require detailed knowledge of HCV prevalence in diverse populations to evaluate the impact of efforts to support WHO HCV elimination goals. Results provide baseline estimates from which to monitor and evaluate progress and by which to benchmark future elimination efforts.