Tuberculosis in Farmers and Their Cattle in Smallholder Farming System in South Gondar Zone of Northwest Ethiopia: Epidemiology and Drug Sensitivity Profiles
No Thumbnail Available
Date
2019-06-05
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis
complex (MTBC), remains a public health problem in Ethiopia. However, there is still
shortage of epidemiological data in different parts of the country, particularly, in the
rural and semi-urban communities. Hence, the present study was conducted to
investigate the epidemiology of TB in farmers and their cattle in South Gondar Zone,
northwest Ethiopia. In addition, the drug sensitivity profile of M. tuberculosis isolated
from TB cases was evaluated. The human aspect of the study was conducted on 2953
individuals using clinical and bacteriological examinations.Region of difference (RD)
9-based polymerase chain reaction (PCR) and spoligotyping were done on the MTBC
isolates. Drug sensitivity pattern of the isolates was analyzed using the GenoType
MTBDRplus assay. The animal aspect of the study was conducted on 95 herds
consisting of 476 cattle using the single intra-dermal cervical comparative tuberculin
test (SICCTT). The study determined TB prevalence of 6.3% (186/2953) in humans
visiting health facilities in the study area. Some of the patients’ demographic
characteristics (patients’ origin, c2 value: 62.80; p<0.001 and age group,c2 value:
35.46; p<0.001) were found to be significantly associated risk factors for TB
infection. Out of 96 M. tuberculosis isolates spoligotyped, 35 spoligotype patterns
iii
were identified, of which 22 were shared typesand consisted of 79 isolates. Thirteen
of these patterns were clustered consisting of 74 isolates making the clustering rate of
77.1%. The dominant shared international types (SITs) were SIT53 (Lineage 4),
SIT149 (Lineage 4) and SIT428 (Lineage 3), each consisting of 18.8%, 12.5% and
12.5% of the total isolates, respectively. The SIT 428 was found to be specific to the
study area and associated with EPTB. From the culture positive M. tuberculosis
isolates, 18.0% (20 /111) were resistant to at least one of the two most effective firstline
anti-TB drugs, isoniazid (INH) and rifampicin (RIF). Multi-drug resistant (MDR)
TB was detected in 1.8% (2/111) of the cases. The high proportion of drug resistant
M. tuberculosis strains in the study area indicates the need for an increased effort to
strengthen TB control program in the study area.The animal and herd prevalence of
bovine TB were 1.5% (7/476) and 7.4% (7/95), respectively with the odds of bovine
TB in cattle owned by TB positive households being slightly higher than those owned
by TB free households. This may suggest the zoonotic transmission potential of TB
from domestic cattle. Overall, the study revealed a relatively high prevalence of TB in
humans and all human isolates were M. tuberculosis and no M. bovis was isolated
from the study population. The failure to detect M. bovis in the study could be due to
the low prevalence of bovine TB in the area.
Description
Keywords
Tuberculosis, Epidemiology, Drug sensitivity, Zoonoses, South Gondar, Ethiopia