Changing Patterns in Epidemiology of Brucellosis in the South of Iran (2015–2020): Based on Cochrane-Armitage Trend Test

Abstract

Background: Brucellosis is known in Iran as an endemic disease; however, its incidence is not the same in all provinces and is higher in some areas. Objective: The present study was designed to determine the epidemiological status and trend of brucellosis in the period from 2015 to 2020 in the south of Fars province, Southern Iran. Methods: This is a cross-sectional analytical study. This study included all patients with brucellosis in the period from 2015 to 2020 whose information had been registered in the Infectious Diseases Center of Larestan city. To collect the data, we used a checklist that included information such as age, gender, number of cases by year and month, occupation, and nationality of the patients with brucellosis. The rate of brucellosis incidence during these years was analyzed using the Cochran-Armitage trend test. P-value less than 0.05 was considered significant. Results: The average annual incidence of the disease was 8.94 per 100 000 population. It has decreased from 26.83 (per 100 000 people) in 2015 to 1.83 (per 100 000 people) in 2020. The results of Cochrane-Armitage process test showed that the reduction in the incidence of the disease from 2015 to 2020 was significant (PTrend = 0.001). The trend of the disease by month also showed that the majority of cases occurred between December and February, with the highest incidence of the disease in February (9.93 per 100 000 people) and the lowest in May (1.1 per 100 000 people) (P = 0.001). Conclusion: Although the results of the present study indicated a decrease in the incidence of the disease in the southern region of Fars province, due to the fact that the disease is common between humans and livestock, there is the possibility of scattered and irregular epidemics in each period.