Epidemiological characteristics of tuberculosis in a mass gathering hosting governorate in Iraq, 2018 – 2022

Tuberculosis (TB) was the first cause of death among communicable diseases before the COVID-19 pandemic. Globally, in 2020, the World Health Organization (WHO) estimated the number of TB patients with negative human immunodeficiency virus (HIV) fatalities was 1.3 million, 80,000 were in the Eastern Mediterranean Region (EMR), and 821 were in Iraq. Karbala Governorate hosted one of the largest mass gatherings in the world. This study aimed to estimate the incidence of TB and identify the sociodemographic and epidemiological characteristics of TB in Karbala, Iraq. The data in this cross-sectional study were retrieved from the TB patients' records. The patients were contacted by telephone to compile missing information WHO standard TB definitions were used. The total number of confirmed TB cases during 2018–2022 was 1005, with an average annual incidence of 15.8/100,000, close to the national TB incidence (15/100,000). Around 48.6 % were aged 25–54 years, with an equal male-to-female ratio. Around 51 % were illiterate, 38.6 % were housewives, and 28.3 % were smokers. Among the four districts in the governorate, the incidence was highest in the city center district that hosted the mass gathering (18.5/100,000 population) (P = 0.000). There were 619 (61.6 %) patients with comorbidities; DM was the most common, 235 (23.4 %). Household contact was reported in 20.4 %, patients with a recent history of being in prison were 1 %, and those on chemotherapy were 10 %. No seasonal pattern in TB reporting was demonstrated. Pulmonary TB constituted 48 %, and the lymph node was the main site of extrapulmonary TB (35 %). The proportion of DR-TB was 2.8 %. While the incidence of TB in Karbala governorate is similar to the national incidence, the incidence in the city center was higher. Most TB patients were in their productive age group. Studying the variation in the geographical distribution and the social consequences of the disease is warranted.