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

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.

Containing the Transmission of COVID-19: A Modeling Study in 160 Countries

“…5) Parameter f was the fatality rate of COVID-19 that was calculated using actual data. 6) Based on a previous study (12), we set the infectious period of symptomatic infection as 5 days and the infectious period of asymptomatic infection as 10 days; therefore, 1/γ = 0.2 and 1/γ ′ = 0.1.…”

“…Mathematical models of pandemics are useful for understanding the early transmission dynamics of infections, achieving pandemic prediction, and evaluating the effectiveness of control measures. They have been widely used in the prediction of the basic reproduction number (R 0 ) of COVID-19, and reports of R 0 for COVID-19 have ranged from 2.6 to 4.71 (6)(7)(8)(9)(10)(11)(12). One recent study suggested that the median R 0 of COVID-19 may be up to 5.7 (13), which was much higher than the previously estimated maximum value of R 0 .…”

“…The extent each country to control the epidemic of COVID-19 in the early stage significantly affect the future development of the global pandemic. Several models, such as the stochastic transmission model (14), and ordinary differential equation model (11,12,15,16), have been used in the research on COVID-19; however, research has yet to be conducted at the global level.…”

Analysis of the epidemiological and clinical characteristics of 65 patients with scrub typhus on the east coast of China

“…The disease's broad global distribution takes the form of a triangle (1,(4)(5)(6), within which more than half of the world's population resides (7)(8)(9). It threatens 1 billion people globally and causes illness in 1 million people annually.…”

“…Common symptoms of typhus infection include fever, eschar, rash, and elevated liver enzymes (4,10). Without timely treatment, pneumonia, meningitis, myocarditis, or disseminated intravascular coagulation can occur, which may lead to multiple organ failure.…”