Prevalence and risk factors of bovine tuberculosis in dairy cattle in Eritrea

Abstract

BackgroundThe prevalence of bovine tuberculosis (BTB) in dairy cattle in the three major milk producing regions of Eritrea was assessed by subjecting 15,354 dairy cattle, 50 % of Eritrea’s dairy cattle population, to the single intradermal comparative tuberculin test (SICTT). Skin test results were interpreted according to guidelines of the World Organization for Animal Health (OIE) with >4 mm as cutoff in skin thickness increase. In addition, we studied the relation between ‘physiological’ variables related to pregnancy and lactation, and the variable ‘region’ on the probability to be skin test positive.ResultsThe BTB prevalences at animal and herd levels were: 21.5 % and 40.9 % in Maekel, 7.3 % and 10 % in Debub, and 0.2 % and 1.6 % in the Anseba region, respectively. Overall, in the regions included, prevalence was 11.3 % (confidence interval (CI) 95 % CI, 11.29 – 11.31 %) and 17.3 % (95 % CI, 17.27–17.33 %), at animal and herd level, respectively. Considering positive herds only, the animal BTB prevalence was 36.8 %, 30.1 %, and 1.8 %, in Maekel, Debub and Anseba, respectively, and the overall animal prevalence within these herds was 32 %. In adult dairy cattle the probability of positive reactivity in the SICTT test was highest in pregnant animals as compared to the other categories.ConclusionThis study reports persistent prevalence of BTB as defined by positive SICTT in the dairy sector of Eritrea, especially in the regions of Maekel and Debub that are located in the central highlands of the country. To our understanding this is the first report that has encompassed all the major dairy farms in Eritrea and it will be instrumental in advocating future BTB control programs in the dairy sector.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-016-0705-9) contains supplementary material, which is available to authorized users.

Genetic analysis of skinfold thickness and its association with body condition score and milk production traits in Chinese Holstein population

“…Skinfold thickness is reported to be related to immune response (Lepper et al, 1977;Ghebremariam et al, 2016), body fat (Bruckmaier et al, 1998), heat tolerance (Bonsma et al, 1953;Muenchen Alfonzo et al, 2016), tick resistance (Carr et al, 1974;Maiorano et al, 2016), reproduction (Siddiqui et al, 2008), and Genetic analysis of skinfold thickness and its association with body condition score and milk production traits in Chinese Holstein population H. Zhang, 1 A. Liu, 1,2 X. Li, 1 W. Xu, 1 R. Shi, 1 H. Luo, 1 G. Su, 2 G. Dong, 3 G. Guo, 3 and Y. Wang 1 * milk yield (Hamid et al, 2000;Kshatriya et al, 2009) in cattle. For example, high negative phenotypic correlations were observed between skinfold thickness over various body regions and milk yield in Kankrej and crossbred cattle (1/4 Holstein Friesian × 1/4 Jersey × 1/2 Kankrej, Sahiwal × indigenous; Hamid et al, 2000;Kshatriya et al, 2009).…”

Genetic profiling of Mycobacterium bovis strains from slaughtered cattle in Eritrea

“…bovis ) is the causative agent of bovine tuberculosis (BTB), achronic, infectious and contagious disease that also affects other domestic animals as well as humans [ 1 , 2 ]. Although BTB is prevalent in dairy cattle in Eritrea as shown by Omer et al (2001) [ 3 ] and Ghebremariam et al (2016) [ 4 ] by skin-test based survey, detection and isolation of the causative agent has never been done. Routine meat inspection at municipal slaughterhouses is performed for identifying tuberculosis-like lesions (TBL) that usually results in either total or partial condemnation of carcasses depending on the level of TBL dissemination, however, confirmatory testing or trace back epidemiological investigations are not conducted in Eritrea.Genotyping is a vital tool for trace back in epidemiological investigations, and according to Biek et al (2012) [ 5 ] results from WGS alone can provide insight into TB epidemiology even in the absence of detailed contact data.…”

Farm-level risk factors associated with bovine tuberculosis in the dairy sector in Eritrea

“…To define farm‐level risk factors associated with positive results in the “single intradermal comparative tuberculin test (SICTT reactors),” as indicator of M. bovis infection, we conducted a case–control study with a 1:1 ratio. A herd was considered a “case herd” when it included at least one SICTT reactor (positive) animal during the 2011 BTB prevalence survey in the dairy sector in Eritrea (Ghebremariam et al., ). In the previous prevalence study (Ghebremariam et al., ), all herds (3,149) and all individual animals (15,354) above 6 weeks of age, from the three selected regions (Maekel, Debub and Anseba), were tested using the SICTT according to OIE.…”

“…A herd was considered a “case herd” when it included at least one SICTT reactor (positive) animal during the 2011 BTB prevalence survey in the dairy sector in Eritrea (Ghebremariam et al., ). In the previous prevalence study (Ghebremariam et al., ), all herds (3,149) and all individual animals (15,354) above 6 weeks of age, from the three selected regions (Maekel, Debub and Anseba), were tested using the SICTT according to OIE. A herd was considered a “control herd” when none of the animals reacted to the test.…”

“…Recently, Ghebremariam et al. () reported 17.3% herd prevalence of bovine tuberculosis in the dairy cattle in the country. The goal of the current study was to investigate the association of potential farm‐level risk factors with this herd prevalence.…”