Epidemiology of tsutsugamushi disease and its relationship with meteorological factors in Xiamen city, China

PLoS Negl Trop Dis. 2020 Oct 15;14(10):e0008772. doi: 10.1371/journal.pntd.0008772. eCollection 2020 Oct.

Abstract

Tsutsugamushi disease (TD) is an acute infectious disease caused by Orientia tsutsugamushi. This study aimed to analyze the epidemiological features of TD, investigate chigger mites and their hosts, and investigate the meteorological factors affecting TD incidence and the host of O. tsutsugamushi in Xiamen city, China. Data on reported TD cases were collected from 2006 to 2018. Spearman's correlation test were used for identifying the relationship between meteorological factors and TD incidence and whether meteorological factors affect the host of O. tsutsugamushi. The incidence of reported TD increased gradually from 2006, reached a peak of 4.59 per 100,000 persons in 2014, and then decreased gradually. The TD incidence was seasonal, with epidemic periods occurred mainly in summer and autumn. Patients aged 40-60 years had the highest proportion of cases, accounting for 44.44% of the total cases. Farmers had the largest number of cases among all occupational groups. Rattus Norvegicus was the most common host, accounting for the largest proportion of rats (73.00%), and the highest rat density was observed in March and October every year. There were significant positive correlations between the number of reported cases and average temperature, sunshine duration, and rainfall as well as between rat density and average temperature. On phylogenetic analysis, 7 sequences of hosts and human TD cases obtained from health records demonstrated the highest similarities to the Kato, Karp, and Gilliam strains. No correlations were observed between rat density, and sunshine duration and rainfall. The transmission of TD in Xiamen city, China, was seasonal, and its incidence was affected by several meteorological factors including average temperature, sunshine duration, and rainfall. However, the host of O. tsutsugamushi was only affected by average temperature.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Animals
  • Child
  • Child, Preschool
  • China / epidemiology
  • Disease Reservoirs / parasitology
  • Female
  • Humans
  • Male
  • Meteorological Concepts
  • Middle Aged
  • Orientia tsutsugamushi / classification
  • Orientia tsutsugamushi / genetics
  • Orientia tsutsugamushi / isolation & purification
  • Orientia tsutsugamushi / physiology*
  • Phylogeny
  • Rats / parasitology
  • Scrub Typhus / epidemiology*
  • Scrub Typhus / parasitology
  • Young Adult

Grants and funding

This study was partly supported by the Bill & Melinda Gates Foundation (INV–005834), the Science and Technology Program of Fujian Province (No: 2020Y0002), the Xiamen New Coronavirus Prevention and Control Emergency Tackling Special Topic Program (No: 3502Z2020YJ03), and the Open Research Fund of State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics (SKLVD2019KF005). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.