Epidemiological features of human brucellosis in Tongliao City, Inner Mongolia province, China: a cross-sectional study over an 11-year period (2007–2017)

Abstract

ObjectivesTo describe the epidemiology of human brucellosis in the past decade and provide evidence of disease control in Tongliao city, which is one of the highest-risk areas of human brucellosis in Inner Mongolia province, China.DesignCross-sectional study.ParticipantsClinically and bacteriologically confirmed human brucellosis cases.Primary and secondary outcome measuresAn analysis of the reported cases of human brucellosis during 2007–2017 was carried out to describe the age, sex and occupational distributions of the cases. The time series analysis model and the geographical information system were explored to describe the seasonality and spatiotemporal distribution, respectively, at the county level.ResultsA total of 13 938 cases of human brucellosis was collected in Tongliao from 2007 to 2017; the majority was aged 25 years to 59 years (85.4%) and the male-to-female ratio was 2.64:1; most of them were agriculturalists (81.9%) and pastoralists (12.4%). The incidence rates increased dramatically from 9.22/100 000 in 2007 to 69.16/100 000 in 2011 with an annual increase of 14.99%. They decreased during 2012–2016 (annual decrease of 8.37%) and rose again in 2017 (44.32/100 000). The disease peaked during March–July, with a clear periodicity and trend of monthly anterior displacement since 2012. Jarud Banner, the region located in the north-west of Tongliao, had the highest accumulated incidence rate (130.1/100 000) compared with other counties. The high-risk regions were spread from the north-west to the south and east of Tongliao during the past decade.ConclusionsThe prevalence of human brucellosis in Tongliao was aggravated during the past decade and peaked during March–July. High-risk areas were mainly concentrated in the counties with extensive prairies and livestock.

Epidemiologically characteristics of human brucellosis and antimicrobial susceptibility pattern of Brucella melitensis in Hinggan League of the Inner Mongolia Autonomous Region, China

“…Farmers and herdsmen comprise the majority of infected cases, as they are regularly in contact with infected animals. This result was consistent with data from Tongliao City, Inner Mongolia [25], most of these were agriculturalists (81.9%) and pastoralists (12.4%), aged 25-59 years (85.4%); the male-to-female ratio was 2.64:1. The proportion of students is second only to that of farmers and herdsmen, Mongolian boys have the custom of playing with lambs, which may increase their risk of infection.…”

“…The increasing trend in incidence rate of human brucellosis in this region coincides with previous studies [24], the rate of human brucellosis infection has rapidly increased in recent years. Tongliao City is one of the highest risk areas for human brucellosis in Inner Mongolia (China), as Tongliao city is geographically close to Hinggan League, incidence rates increased dramatically from 9.2/100 000 in 2007 to 69.2/ 100 000 in 2011, then decreased from 2012 to 2016; incidence rates rose again in 2017 to 44.3/100 000 [25]. The incidence of human brucellosis was high from 2014 to 2018 in Huludao, China, primarily due to contact with domestic animals without sufficient protective measures [26].…”

Spatial and Temporal Distribution Changes of Human Brucellosis in Inner Mongolia, China, effects of Husbandry and Control Measures

“…Farmers use the same living space with livestock, make it easy to contact sick animals. Lower awareness of the transmission of Brucella by livestock, also make the farmers more likely to be infected with Brucella (22). The incidence of herdsmen and livestock-related workers is high, because they are often exposed to livestock.…”

Factors Associated With Diagnostic Delays in Human Brucellosis in Tongliao City, Inner Mongolia Autonomous Region, China

“…), and laboratory tests (rose bengal plate agglutination test, bacterial isolation, serum agglutination test, complement fixation test, etc.) were included in the study (10,16). All case patients were not involved in this study.…”

“…The Inner Mongolia Autonomous Region is one of the most critical areas for livestock husbandry, a historically endemic area of HB in China, accounting for approximately 40% of new cases in the country in recent years (9). In particular, Tongliao, an essential pastoral area in eastern Inner Mongolia, has known endemicity of HB with an incidence of 9.22-38.56/100 000 during 2007-2017 (10). Thus, it is necessary to focus on endemic areas of HB for disease control strategies.…”