Prevalence of pulmonary TB and spoligotype pattern of Mycobacterium tuberculosis among TB suspects in a rural community in Southwest Ethiopia

Abstract

Background In Ethiopia where there is no strong surveillance system and state of the art diagnostic facilities are limited, the real burden of tuberculosis (TB) is not well known. We conducted a community based survey to estimate the prevalence of pulmonary TB and spoligotype pattern of the Mycobacterium tuberculosis isolates in Southwest Ethiopia. Methods A total of 30040 adults in 10882 households were screened for pulmonary TB in Gilgel Gibe field research centre in Southwest Ethiopia. A total of 482 TB suspects were identified and smear microscopy and culture was done for 428 TB suspects. Counseling and testing for HIV/AIDS was done for all TB suspects. Spoligotyping was done to characterize the Mycobacterium tuberculosis isolates. Results Majority of the TB suspects were females (60.7%) and non-literates (83.6%). Using smear microscopy, a total of 5 new and 4 old cases of pulmonary TB cases were identified making the prevalence of TB 30 per 100,000. However, using the culture method, we identified 17 new cases with a prevalence of 76.1 per 100,000. There were 4.3 undiagnosed pulmonary TB cases for every TB case who was diagnosed through the passive case detection mechanism in the health facility. Eleven isolates (64.7%) belonged to the six previously known spoligotypes: T, Haarlem and Central-Asian (CAS). Six new spoligotype patterns of Mycobacterium tuberculosis , not present in the international database (SpolDB4) were identified. None of the rural residents was HIV infected and only 5 (5.5%) of the urban TB suspects were positive for HIV. Conclusion The prevalence of TB in the rural community of Southwest Ethiopia is low. There are large numbers of undiagnosed TB cases in the community. However, the number of sputum smear-positive cases was very low and therefore the risk of transmitting the infection to others may be limited. Active case finding through health extension workers in the community can improve the low case detection rate in Ethiopia. A large scale study on the genotyping of Mycobacterium tuberculosis in Ethiopia is crucial to understand transmission dynamics, identification of drug resistant strains and design preventive strategies.

Prevalence and Incidence of Smear-Positive Pulmonary Tuberculosis in the Hetosa District of Arsi Zone, Oromia Regional State of Central Ethiopia

“…The 130.2/100,000 adjusted prevalence estimate of BCTB cases identified in this study is higher than the 34/100,000 reported from China and the 76/100,000 from Southwest Ethiopia [12]. Nonetheless, it is lower than the 169/100,000 report from Northern Ethiopia [27] and the 278/100,000 from the Lao PDR [28].…”

“…Conversely, it is higher than previous reports that ranged from 30 to 80/100,000 population in different parts of the country [12, 14, 30], the 90/100,000 from Eritrea [31] and the 95/100,000 from Bangladesh [32]. Still, it is lower than the145/100,000 population reported from Vietnam [33], and the 169/100,000 population reported from Northern Ethiopia [27] and India [34].…”

Tuberculosis Infection in Cattle and Cattle Owners in North Eastern Parts of Ethiopia

“…A tuberculosis survey conducted from October 2010-June 2011 in Ethiopia, indicated 0.2% (110/51667) culture positivity from pulmonary TB suspected cases [48]. A study conducted in the rural community of South-west Ethiopia revealed a culture positivity of ~4% (17/482) [49]. The current result lies within the limits of the two findings.…”

Sex Differences in Tuberculosis Burden and Notifications in Low- and Middle-Income Countries: A Systematic Review and Meta-analysis

“…The prevalence of bacteriologically positive TB was reported by sex in 56 surveys with 2.2 million participants in 24 countries [29,30,32,33,35,36,38–44,47–51,53,55,56,58–60,65–67,69–74,82,84,85,87,89–94,97,101,102,104,105,107,110–112]. Forty surveys with 1.7 million participants in 22 countries reported the prevalence of smear-positive TB by sex [35,40,43,44,48–51,53,55,56,58–60,65–67,69–71,73,74,85,87,89,90,92,94,97,101,102,105,107,110,111].…”