The epidemiology of patients with toxoplasmosis and its associated risk factors in Taiwan during the 2007-2020 period

Background Toxoplasmosis is a zoonotic parasitic disease caused by the protozoan Toxoplasma gondii (T. gondii), and may cause miscarriage and birth defects during pregnancy. This study aimed to assess the epidemiological features, epidemic trends, and correlations between the before number of confirmed toxoplasmosis cases in Taiwan from 2007 to 2020 in gender, age, season, and residential area, and hypothesized the environmental and climate factors also might affect the disease in Taiwan. Methods This study reviewed publicly available annual summary data on reported toxoplasmosis cases in the Taiwan Centers for Diseases Control (TCDC) between 2007 and 2020. Results This study collected 150 confirmed domestic and nine patients with imported toxoplasmosis. There was an increasing trend in the incidence of toxoplasmosis, 0.09-0.89 cases per 1,000,000 people, peaking in 2017. The average annual toxoplasmosis incidence was 4.4, 13, and 18 during 2007-2011, 2012-2016, and 2017-2020, respectively. Comparing sex, age, season, and place of residence, the incidence rate was highest in male, 20-39 years-old patients, summer, and the eastern region, with 1.02, 1.72, 0.38, and 3.63 cases per million population, respectively. Additionally, comparing the distribution of cases by age group in Taiwan, there were significant differences between 40-59 years-old in the northern region (odds ratio (OR) = 0.343, 95% confidence interval (CI) = 0.167-0.705, p = 0.004) and 40-59 years-old in the southern region (OR = 4.488, and 95% CI = 2.149-9.374, p< 0.001), respectively. Linear regression analysis also showed that PM (particulate matter) 2.5 (mu g/m(3)) concentration was positively associated with toxoplasmosis (beta = 0.095, p = 0.037). CO concentration was negatively correlated with toxoplasmosis (beta = -14.001, p = 0.021). Conclusions This study is the first to report domestic and confirmed cases of imported toxoplasmosis from the surveillance data of the TCDC between 2007 and 2020. It identified that residence and age were associated with an increased risk of toxoplasmosis in Taiwan. This study confirmed that toxoplasmosis remains a prevalent infectious disease in Taiwan, its epidemic is gradually increasing and becoming more severe. These findings might be useful for policy-makers and clinical experts to direct prevention and control activities to patients with T. gondii, which causes the most severe illness and greatest burden to Taiwanese people.