Prevalence of pulmonary tuberculosis in Al-Najaf governate, Iraq [version 1; peer review: awaiting peer review]

Background: pulmonary tuberculosis (PTB) is one of the most global dangerous infectious diseases worldwide, particularly in developing countries. Mycobacterium tuberculosis (Mtb) is the most infectious agent that caused PTB transferred by air droplets from one person to other. In the present epidemiological study, we aimed to record the total numbers and percentages of patients infected with PTB caused by Mtb during 12 months in AL-Najaf Governorate, Iraq. Methods: This study has been done in 2019 from January to the end of December in the north and south region of AL-Najaf Governorate, Iraq. Sputum of PTB-patients has been stained by Ziehl–Neelsen to Mtb diagnosis according to World Health Organization (WHO) recommendation. Results: We recorded 174 PTB-patients in AL-Najaf Governorate 2019; 89 male and 85 female; 101 and 73 in the north and south sections respectively. The age group 16-24 was the highest infected. Quarter two recorded the highest numbers of PTB-patients; 33 (60%) in the north section and 22 (40%) in the south section. Conclusion: There was low PTB incidence in AL-Najaf Governorate 2019 but the Youngers were the most susceptible to infection. Infection in the north section was higher than in the south section and there were no high differences between genders. Seasons have no high effect on the number of infections.


Introduction
Health awareness is one of the most important reasons to avoid different infection such as pulmonary-TB and COVID-19. 1 The developing countries are the most infected with these types of infections. 2,3 Pulmonary-TB considered as the most infection caused by Mtb and can cause many dangerous complicated in the lung lead to death in many times. 4 Pulmonary-TB is a contagious disease that is a major cause of illness and one of the top causes of mortality around the world and was the biggest cause of mortality from a single infectious agent until the COVID-19 pandemic, ranking ahead of many infections such as acquired immunodeficiency syndrome (AIDS). 5,6 More than 80% of pulmonary-TB patients can be successfully treated with a six to nine-month drug regimen. Many factors can lead to PTB progress such as smoking, malnutrition, diabetes, poverty and absent of health awareness. 7,8 In 2020, milestone of about more than 30% reduction in the absolute number of PTB deaths between 2015 and 2020. 9 Al-Najaf Governorate is one of the most important holy cities in Iraq, about 180 kilometers south of Baghdad capital of Iraq and its estimated population about 1,500,000 people and it is crowded Governorate as compared with other because of highly percentage of visitors came to it from inside and outside of Iraq over the year. 2 This feature may be lead to fast transmit of different pandemic diseases in population such as COVID19 and PTB. 10,11 According to important features above, the main goal of this study is to detect the prevalence of numbers and percentages of PTB-patients caused by Mtb in AL-Najaf Governorate during one year to find the most important ways to avoid this deadly disease in future.

Research ethics
The authors confirm that they are getting verbal agreement from Mtb-patients in this study. We confirm that we have obtained all the original approvals from Specialized Center for Chest and Respiratory Disease in AL-Najaf Governorate (23895/2019) in order to collect samples and follow up on patients and all data that related with research.

Study design
This epidemiological study has been performed under supervisor of Specialized Center for Chest and Respiratory Disease in AL-Najaf Governorate during one year from the first January to end of December 2019. In this study, two main sections have been studied; north and south section. According to seasonal variation, study was divided to four quarters as follow: quarter one include January, February and March. Quarter two; April, May and June July. Quarter three; July, August and September. Quarter four; October, November and December.

Diagnosis of Mtb in PTB-patients
Sputum has been collected from all suspected patient infected with PTB as follows; fasting sputum were collected from the same patient in three days respectively, and made slide stained with Ziehl-Neelsen. Appearance of red bacilli has been considered as positive infection with Mtb. 12,13 Statistical analysis Graph-Pad Prism computer software has been used to detect the numbers and percentages of PTB-patients caused by Mtb according to ages, gender and seasonal variation. [14][15][16] Results

Total PTB-patients
The results indicated in Table 1 there were 174 PTB-patients in AL-Najaf Governorate; 89 male 51.1% and 85 female 48.9%. Out of total 174, there were 101(58%) in north section and 73(42%) in south section of the Governorate. According to age groups, Table 2 shows the age group 16-24 was the most infected with PTB that recorded 52 patients 29.9% followed by 55-64 which recorded 45 patients 25.9%.

Seasonal infections
Thirty eight PTB-patients have been recorded in quarter one distributed as follows: 22 patients 57.9% in north section and 16 in south section 42.1%. Age group 16-24 was the highest infected with 13 cases 34.2% while the 25-34 was the lowest

Discussion
Al-Najaf is a tourist governorate in Iraq, attracting millions of tourists from within Iraq and abroad annually and inhabited by a high percentage of the population. Therefore, it is necessary to study the most important epidemic diseases that may be dangerously and quickly transmitted in this type of crowded population. 17,18 In this epidemiological study we divided Al-Najaf Governorate in two sections: north and south (Table 1), the results demonstrated that north section was higher than south section according to total infection in 2019, this result is may be due to the increase in the population and the large number of rural and crowded areas in north section more than south section. 2,19 Also, Table 1 proved that there was approximately equal frequency in numbers of male and female infected with PTB; 89 and 85 respectively, while other researchers proved that PTB rates are significantly higher in male than in female. [20][21][22] In this study, the equal numbers of male and female infected with PTB may be due to there have their equal involvement in society and public life. 23 Therefore, man and women are vulnerable to PTB in equal percentage. Male and female have different combinations of risk factors for PTB but the main reason still not fully unclear. 24 Out of five age groups, we documented in Table 2 the age group 14-26 was the highest infected with 52 patients 29.9%. We think this is dangerous indicator in young age groups and the reason may be due to low health awareness, malnutrition and hookah smoking. 25,26 Martinez et al. (2017) 12 recommended that focusing PTB preventive efforts on home contacts is extremely beneficial. However, beyond the family, a significant portion of transmission may occur at the communal level. 27 Therefore, we must increasing health awareness among young people and holding seminars to focus on the seriousness of this deadly disease to protecting children at risk for tuberculosis transmission in communities and households should be recommended. Poor health system development, scarcity of medical care and socio-economic factors and have been linked with increased risk of PTB on individual and population levels in developing countries. 28,29 These factors cannot account for the seasonality of PTB incidence, which has been seen in many parts of the world. According seasonal variation, quarter two recorded 55 cases it is the highest numbers of PTB-patients. Much research recorded a high numbers in infections in the warm seasons. 30,31 Al-Najaf Governorate has hot climate in most of year with hot shiny sun, therefore, most peoples try avoiding the sun light that lead to decrease in vitamin D that support innate immune responses to Mtb. 32,33 Skin is the important source for Vitamin D synthesis dependent upon sunlight exposure. The low exposure to sunlight during summer and winter could lead to vitamin D deficiency and subsequent that leads to low innate immune response and may be increase to Mtb infection. 34,35 Conclusion There were low PTB-patients numbers in AL-Najaf Governorate in 2019 but the Youngers were the most susceptible to infected. Infection in north section was higher than south section and there were no high differences between genders.
Seasons have no high effect on the number of infections.

Data availability
All data has been included in this manuscript.
Raw data of patients infected with tuberculosis/2019