Immunopathogenesis Of Chlamydia trachomatis Infection

National Institute Of Allergy And Infectious Diseases

Investigators

Linked publications & trials

Abstract

Chlamydia trachomatis is the most common sexually transmitted bacterial pathogen in the world and in the U.S., causing serious complications on women's reproductive health including ectopic pregnancy, pelvic inflammatory disease and infertility. C. trachomatis also causes infection of the eye resulting in inflammation and in some cases blindness. The objectives of this project are to define the epidemiology, risk factors, transmission kinetics, and pathogenesis of C. trachomatis in different population settings, including resource constrained countries. In such geographical areas, trachoma due to C. trachomatis infection is the most common cause of infectious blindness in the world. The WHO has recommended that three rounds of mass drug administration (MDA) with antibiotics be offered to control the disease in districts where the prevalence of follicular trachoma (TF) is >10% in children aged 1-9 years, with treatment coverage of at least 80%. We have conducted both surgical and antibiotic treatment intervention studies in Gambia, Niger, and Tanzania in efforts to control trachoma. However, the source of infection following mass treatment is often unknown. We sought to determine, in a cross-sectional survey of households of children with active trachoma, if we could detect the presence of Chlamydia trachomatis on household objects and on family members based on sleeping and caretaking patterns. In five villages in Kongwa, Tanzania, children <five years were randomly chosen for examination for trachoma, and households of all children with active trachoma were eligible for this study. Environmental swabs of bedding, furniture, clothing, and hands were taken and processed using Amplicor for detecting C. trachomatis DNA. The presence of an infant <1 year of age in the household, and whether the children's clothing had not been recently washed. C. trachomatis DNA is present in the environment of children with active trachoma, especially in households with an ocular infection. Specific findings also suggest that washing hands, clothing, and bedding may be important. As more endemic regions approach the elimination goal, it becomes critical to identify proper methods of surveillance for re-emergence. A total of 2536 children were surveyed for specific antibodies to C. trachomatis at baseline and 1719 made all four surveys over three years of follow up. There was no difference by age, baseline trachoma, infection, or seropositivity in the cohort versus those who dropped out. Baseline trachoma rates were 5.2% and stayed below 5% at all follow up visits. Seropositivity was 31.5% at baseline and increased to 36.4% at the third follow up. Of the 522 children who were seropositive at baseline, most (450 or 86%) were still seropositive at all three follow up surveys (Table 1). 63 (12%) were seroreverters and stayed negative to the last survey. Only 5 children experienced a transient seroreversion. Only four children who were seropositive at baseline had unstable serostatus throughout the follow up, and all but one had MFI-BG values in the indeterminate range, suggesting they could be also stable seroreverters. In summary, our study in a cohort of children demonstrated the dynamics of seroconversion and seroreversion in younger children in this formerly endemic district, reflecting the heterogeneity of the communities even with overall low rates of disease and infection. Several national guidelines consider illicit drug use as an indication for testing for some STIs. Sex-specific prevalence of T. vaginalis and/or C. trachomatis infection was examined by past-year marijuana use among 2958 sexually experienced, 20- to 39-year-old participants of the 2013-2016 National Health and Nutrition Examination Surveys. Past-year marijuana use was reported by 27.3% and 36.3% of females and males, respectively. Male and female past-year marijuana users were more likely to have new and multiple sexual partners in the past year (P < 0.05). Past-year marijuana use was associated with prevalent C. trachomatis and/or T. vaginalis infection among females (7.4% vs. 2.9%) and males (4.0% vs. 1.1). This association was attenuated after propensity score covariate adjustment among females and males. In conclusion, sexually transmitted infection prevalence was higher among persons with a past-year history of marijuana use; however, this association was not significant after accounting for measured confounders. Additional work is needed to characterize STI prevalence by the mode, duration, and frequency of marijuana. This will be the last year of the Chlamydia Annual Report as this PI's intramural chlamydia lab is closing.