Controlling Bovine Brucellosis In The State Of São Paulo, Brazil: Results After Ten Years Of A Vaccination Program

A cross- sectional study was carried out, between May and November 2011, to estimate the situation of the bovine brucellosis in São Paulo State, 10 years after the commencement of the vaccination of the heifers with the S19 strain. The State was divided into seven regions and in each of them, 300 farms with reproductive activity were randomly chosen and considered as primary sample units. A fixed number of cows was randomly selected and tested for antibodies against Brucella spp. A farm was considered infected if at least one female tested positive. In the selected farms, an epidemiological questionnaire was administered which focused on herd traits as well as husbandry and sanitary practices that could be associated with the risk of infection. The prevalence (percentile, [95% confidence interval]) of infected herds was 10.2% [8.8-11.8] for the State, and for the regions, it varied from 7.3% [4.7-11.2] to 12.3% [8.8-16.8], not showing significant difference between different regions. The apparent prevalence of positive farms in the State and regions remained similar to the prevalence observed 10 years before. The prevalence of positive animals was 2.4% [1.8-3.1] in the State and varied from 1.1% [0.6-2] to 3.5% [1.7-7.1] in the regions, not showing significant difference between regions. Again, there was no difference in the prevalence of positive animals after 10 years of the vaccination program. The risk factors (odds ratio, 95% confidence interval) associated with bovine brucellosis in the State included number of cows = 24 (3.08, 2.22-4.27) and the acquisition of breeding animals (1.33, 0.95-1.87). The São Paulo State should conduct systematic vaccination coverage of above 80% of the eligible heifers with the S19 strain vaccine annually. Moreover, the State should emphatically use RB51 strain vaccine in females above 8 months of age not vaccinated with S19 strain vaccine. An efficient animal health education program to orientate farmers to test replacement animals for brucellosis prior to introduction in their herds should also be implemented.3753505351

Prevalence And Risk Factors For Bovine Tuberculosis In The State Of São Paulo, Brazil

A cross sectional study was carried out between May and November 2011 to investigate the epidemiological situation of bovine tuberculosis (bTB) in the state of São Paulo, Brazil. The state was divided into seven regions. Three hundred farms from each region, with reproductive activity, were randomly chosen and included as primary sample units. A fixed number of bovine females, older than 2 years of age, were randomly selected and tested, using the comparative cervical tuberculin test. An epidemiological questionnaire based survey was conducted in the selected farms. Our results show that in the state of São Paulo, the apparent prevalence of positive farms was 9% (95% confidence interval, 95% CI = 7.8 - 10.5%). The prevalence in the individual regions varied between 3.5% (95% CI = 1.7 - 6.8%) and 13.9% (95% CI = 10.2 - 18.8%). The apparent prevalence of positive animals in the state was 1.3% (95% CI = 0.9 - 1.7%) and varied from 0.3% (95% CI = 0.2 - 0.6%) to 2.5% (95% CI = 1.4 - 4.5%) in the regions. The risk factors associated with tuberculosis in the state were (i) number of adult females in a herd is = 24 (Odds ratio, OR = 1.91, 95% CI = 1.32 - 2.75), (ii) type of farm enterprise (dairy: OR = 2.70, 95% CI = 1.40 - 5.21; mixed: OR = 2.03, 95% CI = 1.08 - 3.82), (iii) milking process (milking parlor: OR = 4.12, 95% CI = 1.46 - 11.64; portable milking machine: OR = 2.94, 95% CI = 1.42 - 6.09), and (iv) pasture sharing (OR = 1.58, 95% CI = 1.07 - 2.33). The state of São Paulo should implement a structured surveillance system to detect and mitigate the disease. Further, an efficient animal health education program, which encourages the farmers to test replacement animals for bTB prior to introduction in their herds and to avoid pasture sharing with farms of unknown sanitary conditions should also be implemented.3753673368

Effect Of Pasteurization On The Decay Of Mycobacterium Bovis In Milk Cream

Milk cream must be pasteurized in order to be sold in Brazil. However, there are no specific legal requirements for this product, and producers set their own pasteurization parameters using the ones approved for milk as a reference. Considering that fat protects bacteria from heat, that no thermal inactivation studies have been performed on Mycobacterium bovis present in cream, and that bovine tuberculosis is endemic in Brazil, the aim of this study was to evaluate the inactivation of M. bovis in milk cream subjected to commercial parameters of pasteurization. Milk cream samples were contaminated and pasteurized in a water bath at 75, 80, 85, and 90°C for 5 and 15 s. M. bovis cells were plated onto Stonebrink-Leslie medium, incubated at 36°C for 45 days, and quantified; the result was expressed in log CFU mL-1. The fat content of the samples ranged from 34% to 37% and the average initial load of M. bovis was 8.0 Log CFU mL-1. The average decay of the M. bovis populations was 4.0, 4.3, 4.9 and 6.7 log CFU mL-1 when the cream was treated for 15 sec at 75, 80, 85 and 90°C, respectively, showing that the efficiency of the heat treatment was improved by increasing the temperature of the process. Given the lipophilic nature of M. bovis, the cream should be subjected to more intense parameters of pasteurization than those applied to milk.3753737374