A cross sectional study was performed to assess the epidemiological status of bovine tuberculosis in the state of Minas Gerais, Brazil, in 2013. The state was divided into seven regions, and a preset number of herds was randomly sampled in each region. From each farm, female cattle aged 24 months or older were randomly sampled and subjected to the comparative cervical tuberculin test (CCTT). Animals with inconclusive test results were re-tested with the same diagnostic procedure after a minimum interval of 60 days. A total of 31?832 animals were tested from 2?182 farms. An epidemiological questionnaire was administered in the farms to identify risk factors associated with bovine tuberculosis. Prevalence in the state was estimated at 4.25% (95% CI: 3.36% – 5.15%) for herds and at 0.56% (95% CI: 0.46% – 0.66%) for animals. Data on herd prevalence for bovine tuberculosis for each stratum showed the highest prevalences at region Sul e Sudoeste (stratum 5) and region Central (stratum 3) which were significantly different from the lowest prevalences found at regions Noroeste, Norte e Nordeste (stratum 1) and region Leste (stratum 2). The highest animal prevalences observed for the region Sul e Sudoeste (stratum 5), region Zona da Mata (stratum 4) and region Central (stratum 3) were significantly different from the lowest ones at region Triângulo Mineiro (stratum 7), region Noroeste, Norte, e Nordeste (stratum 1) and region Leste (stratum 2). The presence of bovine tuberculosis was associated with animal purchase from cattle traders (OR?=?2.59 [95% CI: 1.28 – 5.20]), higher yield intensive dairy (OR?=?7.55 [95% CI: 1.89% – 30.09%]) and non-intensive dairy production (OR?=?3.58 [95% CI: 1.06% – 12.04%]), as well as with herds with 30 or more cows (OR?=?1.97 [95% CI: 1.02 – 3.80]). Non-specific reactors to the CCTT were found in 95.07% (95% CI: 94.05% - 96.09%) of the herds. Therefore, the state of Minas Gerais should implement surveillance systems for the detection and sanitation of infected herds, preferably incorporating risk-based surveillance elements, considering the results of the present study.

With the aim of supporting the strategic planning of the National Program for Control and Eradication of Brucellosis and Tuberculosis, different Brazilian states have been conducting cross-sectional studies, coordinated by the Ministry of Agriculture, Livestock, and Supply and with scientific support from the University of São Paulo and the University of Brasilia. In Santa Catarina, the State Animal Health Agency (CIDASC) conducted a study on bovine tuberculosis (TB) prevalence and assessment of risk factors in 2012. The state was divided into five regions and, in each region, independent sampling was performed in two steps: (i) cattle herds with reproductive activity were randomly selected; and (ii) in each herd, a sample of females aged 24 months or older underwent the intradermal comparative tuberculin test. A questionnaire was used to collect data on production characteristics and management practices that could be associated with the tuberculosis infection. Herd prevalence of bovine TB was 0.50% (95% confidence interval [CI]: 0.074–0.93%) while the prevalence of TB in adult females was 0.06% (95% CI: 0–0.12%). No significant difference in the prevalence of infected herds and of positive females was observed among the five regions. The logistic regression model revealed that herds with 19 or more females showed an odds ratio (OR) of 7.68 (95% CI: 1.22–48.39) compared to smaller herds, while dairy herds presented an OR of 10.43 (95% CI: 2.00–54.25) relative to beef or dual-purpose herds. The results suggest that dairy herds, in which animals are kept in partial or total confinement, and larger herds, which tend to acquire animals more often, are at a higher risk of bovine TB. Given the low prevalence and the type of higher-risk properties, a bovine TB surveillance system should be targeted at the state’s dairy basins, particularly the western region that accounts for the major industries and more intensive dairy farms.

Considering the implementation of the National Program for the Control and Eradication of Animal Brucellosis and Tuberculosis (PNCEBT) in 2001, and the need to determine the epidemiological status of animal tuberculosis for future evaluation of the effectiveness of the measures laid down, the objective of this study was to estimate the prevalence and identify risk factors of bovine tuberculosis in the Federal District (DF) of Brazil, as well as to provide an input for the strategic management of PNCEBT. Field testing and data collection was carried out from February to December 2003. The DF was considered a single epidemiological region owing to the small number of existing farms, and the absence of significant differences between the region’s farming enterprises, which would justify the stratification of the regional sample. A total of 278 farms were randomly sampled from the local registry database of bovine farms with reproductive activity, in which 2,019 adult cows were tuberculin tested. Only one sampled animal had a positive result, using the comparative cervical tuberculin test, resulting in a bovine tuberculosis prevalence of 0.05% [95% CI: 0.0-0.4%]. The herd-level prevalence of bovine tuberculosis in the DF was estimated as 0.36% [95% CI: 0-2.0%]. The analysis of risk factors was impaired by the results obtained, as the number of cases did not allow for this kind of analysis. Cattle farming in the DF is predominantly aimed at dairy production; however, it is characterized by the presence of small low milk yield herds, which may not favor the introduction and persistency of infection of Mycobacterium bovis. Health authorities from the DF perform surveillance for bovine tuberculosis and maintain the need for tests for the movement of bovines for breeding and those animals destined for any form of animal gathering, especially auctions. Therefore, it is likely that the DF has good conditions for successfully implementing the PNCEBT.

Seroprevalence and risk factors for bovine brucellosis in Minas Gerais State, Brazil

Bovine tuberculosis results in economic losses in livestock production and poses a risk to public health. This study aimed to characterize the epidemiological status of bovine tuberculosis in adult cows in the state of Goiás, Brazil. The state was divided into three sampling strata, corresponding to different livestock production circuits. A total of 18,659 animals were tested with the comparative cervical tuberculin test (CCT), in 300 randomly sampled bovine herds per stratum. An epidemiological questionnaire was used to identify health and management practices that may be associated with the presence of tuberculosis infection in the herd. In Stratum 1, dominated by beef cattle, no animals reacted to the CCT. In Stratum 2, which covers the main dairy regions of the state, the prevalence was estimated at 8.67% [5.73 to 12.74%] for herds and at 0.9% [0.21 to 1.58%] for animals. In Stratum 3, characterized by a mix of dairy, beef and dual-purpose herds, the prevalence was estimated at 1.00% [0.21 to 2.89] for herds and 0.30% [0.10 to 0.49 %] for animals. The overall prevalence in the state of Goiás was 3.43% [2.20 to 4.67%] for herds and 0.30% [0.10 to 0.49%] for animals. The multiple logistic regression analysis revealed that herd-level risk factors associated with the presence of the bovine tuberculosis are: the location of the herd in Stratum 2 (OR = 12.05 [3.52 to 41.28]) and the number of times a cow is milked per day (OR = 6.27 [2.72 to 14.44]). Regular veterinary care was identified as a protective factor (OR = 0.38 [0.15-0.94]). These results indicate that bovine tuberculosis is endemic in the state; its spatial distribution is heterogeneous with a strong concentration in dairy regions. The most intensive dairy farms are those with the highest risk, which is consistent with what other authors’ found elsewhere in Brazil. The epidemiological information generated by this study provides information for planning of risk-based surveillance actions, and justifies the adoption of free-herd certification programs for bovine tuberculosis in the main dairy regions of Goiás.

Bovine tuberculosis is a zoonosis with worldwide distribution. Its control has a direct impact on public health and livestock production. This study estimated the prevalence of infected herds and adult bovines and evaluated risk factors associated with the presence of tuberculosis within herds in the state of Paraná. The state was divided in seven livestock regions and independent sampling was performed. A total of 1,419 farms were sampled and 16,045 animals were tested using the intradermal comparative cervical tuberculin diagnostic test. The apparent and estimated prevalence rates in farms and adult bovine animals were 2.15% (95% CI: 1.31-3.00) and 0.42% (95% CI: 0.04-0.81), respectively. It was not possible to state with 95% confidence that the disease prevalence in any region was significantly different from that in other regions. There were no positive animals in the western region, and the prevalence of positive herds and animals in the other regions ranged from 1.03% to 3.89% and 0.17% to 1.08%, respectively. The logistic regression model identified larger herd size (OR = 2.4) and mechanical cmilking (OR = 5.18) as risk factors associated with the presence of bovine tuberculosis. The combination of low prevalence with risk factors associated to larger herds and more intensive dairy farming, renders the state of Paraná a good candidate for the implementation of industry-based free-herd accreditation schemes and makes a case for planning risk-based surveillance targeted at major dairy basins.