Hot and Cold Spot Areas of Household Tuberculosis Transmission in Southern China: Effects of Socio-Economic Status and Mycobacterium tuberculosis Genotypes.

Jing Ou,Dingwen Lin,Prasit Palittapongarnpim,Virasakdi Chongsuvivatwong,Angkana Chaiprasert,Zhezhe Cui,Edward A. Graviss,Jinming Zhao,Mei Lin

doi:10.3390/ijerph16101863

Abstract

The aims of the study were: (1) compare sociodemographic characteristics among active tuberculosis (TB) cases and their household contacts in cold and hot spot transmission areas, and (2) quantify the influence of locality, genotype and potential determinants on the rates of latent tuberculosis infection (LTBI) among household contacts of index TB cases. Parallel case-contact studies were conducted in two geographic areas classified as “cold” and “hot” spots based on TB notification and spatial clustering between January and June 2018 in Guangxi, China, using data from field contact investigations, whole genome sequencing, tuberculin skin tests (TSTs), and chest radiographs. Beijing family strains accounted for 64.6% of Mycobacterium tuberculosis (Mtb) strains transmitted in hot spots, and 50.7% in cold spots (p-value = 0.02). The positive TST rate in hot spot areas was significantly higher than that observed in cold spot areas (p-value < 0.01). Living in hot spots (adjusted odds ratio (aOR) = 1.75, 95%, confidence interval (CI): 1.22, 2.50), Beijing family genotype (aOR = 1.83, 95% CI: 1.19, 2.81), living in the same room with an index case (aOR = 2.29, 95% CI: 1.5, 3.49), travelling time from home to a medical facility (aOR = 4.78, 95% CI: 2.96, 7.72), history of Bacillus Calmette-Guérin vaccination (aOR = 2.02, 95% CI: 1.13 3.62), and delay in diagnosis (aOR = 2.56, 95% CI: 1.13, 5.80) were significantly associated with positive TST results among household contacts of TB cases. The findings of this study confirmed the strong transmissibility of the Beijing genotype family strains and this genotype’s important role in household transmission. We found that an extended traveling time from home to the medical facility was an important socioeconomic factor for Mtb transmission in the family. It is still necessary to improve the medical facility infrastructure and management, especially in areas with a high TB prevalence.

Highlights

IntroductionTuberculosis (TB) continues to be a global global concern concern because because of of its itshigh highinfectivity, infectivity, pathogenicity, pathogenicity, mortality, and cost of therapy.therapy
By comparing the different subgroups, in these study-targeted areas, we investigated the differences in the prevalence and transmissibility of Mycobacterium tuberculosis (Mtb) at the household level
The TST positive rate among household contacts in the hot spot areas was 35.7%, significantly higher than that in cold spot areas (24.2%); and with multivariate analysis, it remained significantly associated with the location

Summary

Introduction

Tuberculosis (TB) continues to be a global global concern concern because because of of its itshigh highinfectivity, infectivity, pathogenicity, pathogenicity, mortality, and cost of therapy. In addition to the extra social and clinical burdens associated with TB disease, the patients’ family family (and (and caregivers) caregivers) are at an increased risk of being infected with the Mycobacterium tuberculosis (Mtb) bacteria [1]. In 2017, the estimated number of TB cases in China was the second highest globally [2]. The. The realization realization of of the the End End TB TB Strategy. Strategy proposed proposed by by the the World World Health. Organization (WHO) is directly related to the performance performance of of TB.

Objectives

Discussion

Conclusion