Suchergebnisse

The isolation of Mycobacterium bovis is critical to a surveillance system for bovine tuberculosis based on detection of lesions in abattoirs. Thus, four solid culture media and three incubation conditions were investigated to elucidate which combination overcomes the others by assessing growth, time to the first appearance of colonies and their number. Ninety-seven samples of granulomatous lesions were submitted to the decontamination procedure by 1-hexadecylpyridinium chloride at 0.75% w/v, and inoculated on two egg-based media, Stonebrink's (ST) and Löwenstein-Jensen's with sodium pyruvate (LJp), and two agar-based media, tuberculosis blood agar (B83) and Middlebrook 7H11 medium (7H11). Each medium was incubated at 37°C for 90 days in three incubation conditions: in air, in air containing 10% carbon dioxide (CO2), and in air in slopes closed with burned hydrophobic cotton and subsequently plugged with a cork to create a microaerophilic atmosphere. The colonies appeared faster and in higher number when incubated in air containing 10% CO2 (p < 0.01), independent of media. B83 showed a faster growth and detected more isolates at 30 days of incubation, when compared to ST (0.0178), LJp (p < 0.0001) and 7H11 (p < 0.0001), though there was no difference between B83, ST and LJp at 60 and 90 days of incubation. 7H11 presented the lowest number of isolates (p < 0.0001) and a longer period for the appearance of the first colony (p < 0.001). According to our findings, the concomitant use of ST and B83 media incubated in air containing 10% CO2 increases the isolation of M. bovis in a shorter period of time, which improves bovine tuberculosis diagnosis.

Testing for detecting the infection by SARS-CoV-2 is the bridge between the lockdown and the opening of society. In this paper we modelled and simulated a test-trace-and-quarantine strategy to control the COVID-19 outbreak in the State of Sao Paulo, Brasil. The State of Sao Paulo failed to adopt an effective social distancing strategy, reaching at most 59% in late March and started to relax the measures in late June, dropping to 41% in 08 August. Therefore, Sao Paulo relies heavily on a massive testing strategy in the attempt to control the epidemic. Two alternative strategies combined with economic evaluations were simulated. One strategy included indiscriminately testing the entire population of the State, reaching more than 40 million people at a maximum cost of 2.25 billion USD, that would reduce the total number of cases by the end of 2020 by 90%. The second strategy investigated testing only symptomatic cases and their immediate contacts - this strategy reached a maximum cost of 150 million USD but also reduced the number of cases by 90%. The conclusion is that if the State of Sao Paulo had decided to adopt the simulated strategy on April the 1st, it would have been possible to reduce the total number of cases by 90% at a cost of 2.25 billion US dollars for the indiscriminate strategy but at a much smaller cost of 125 million US dollars for the selective testing of symptomatic cases and their contacts.

Preservation of specimens during transportation between abattoirs and diagnostic laboratories defines a critical stage in the definitive diagnosis of bovine tuberculosis by the isolation of Mycobacterium bovis. A 2-step study was designed to verify the maximum time that tissue samples can be stored in saturated sodium borate solution (SSB) with the highest detection of M. bovis isolates. Ninety hamsters were inoculated intraperitoneally with a suspension of M. bovis strain AN5 and were humanely euthanized after 40 days. Their spleens were collected and stored in SSB during four distinct periods (30, 60, 90 and 120 days) with incubation at two temperatures (27°C and 37°C). The control group was cultured on the day of euthanasia. Sixty-nine suspected tuberculous lesions samples were collected in the abattoir and were stored in SSB for three periods (30, 60 and 90 days) at 27°C in the laboratory. The bovine control group was cultured on the day of entry in the laboratory. Both experiments were analyzed separately based on the growth proportion of isolates and the number of colonies. SSB was able to maintain the viability of most M. bovis at high temperatures for up to 30 days. A progressive decline was observed with other storage periods at 27°C, and no growth was obtained after 60-day storage at 37°C. Despite the loss in viability of M. bovis, SSB is the most favorable choice to preserve specimens during transportation across a large country with high variation in environmental temperature. The sensitivity of M. bovis detection by bacteriological examination is inversely proportional to storage time. Therefore, the storage of tuberculous lesion specimens in SSB is recommended to not exceed 30 days at 27°C before cultivation.

Research, development of new biotechnological methods, diagnostic tests, confirmation of results, and reinvestigations are possible because of the availability of well-preserved living organisms maintained without any changes. Cryopreservation is a simpler, more reliable and long-term stable method for culture maintenance. Storage temperature and composition of the suspending vehicle are factors that affect the viability of mycobacterial strains. Three vehicles and three storage temperatures were evaluated to define a suitable cryoprotective medium for the preservation of Mycobacterium bovis strains. Colonies of sixteen M. bovis isolates were used to prepare the suspensions, which were then added to three vehicles: sterile 0.85% saline solution (SS), Middlebrook 7H9 broth (7H9), and Middlebrook 7H9 broth with sodium pyruvate (7H9p) replacing glycerol. Aliquots of these suspensions were frozen by three different methods, directly in the -20°C freezer, directly in the -80°C freezer, and at -196°C by immersion in liquid nitrogen (LN). The frozen aliquots were thawed at room temperature after 45, 90 and 120 days. Mycobacterial viability was assessed by counting the living cells on plates of Stonebrink medium before and after the freezing procedure. Storage at -20°C exhibited a lower recovery of M. bovis compared to storage at -80°C (Dunn's test, p=0.0018) and LN (Dunn's test, p=0.0352). There was no statistically significant difference between storage at -80°C and in LN (Dunn's test, p=0.1403), yet -80°C showed better results than LN. All three suspending vehicles showed no statistically significant difference in terms of viability (Friedman's test, p=0.7765). Given the low loss proportion of 5% during storage at -20°C and the high cost equipment required for storage at -80°C and LN, we recommend storage at -20°C or -80°C, when this is available, for preservation of M. bovis field strains.

The Brazilian Ministry of Agriculture, Livestock and Food Supply established the National Program for Control and Eradication of Brucellosis and Tuberculosis (PNCEBT) in 2001. One of the main strategies adopted by the program is the mandatory vaccination of heifers between three and eight months of age with the B19 strain. In 2007, Brazil allowed the use of RB51 vaccine in bovine females over 8 months of age as an option for the producer, but kept the B19 strain as a mandatory vaccine. This decision is based on the assumption that combining the two vaccines allows to achieve significant vaccination coverage sooner and, consequently, accelerates the fall speed of prevalence. Thus, this study aimed to measure the impact of the combined use of these two vaccines in reducing the prevalence, using as a tool the mathematical modeling. It was concluded that vaccination by RB51, if adopted as a complement to vaccination by B19, mean decrease in the prevalence of bovine brucellosis in less time.

Given the speed of air travel, diseases even with a short viremia such as dengue can be easily exported to dengue naive areas within 24 hours. We set out to estimate the risk of dengue virus introductions via travelers into Europe and number of secondary autochthonous cases as a result of the introduction. We applied mathematical modeling to estimate the number of dengue-viremic air passengers from 16 dengue-endemic countries to 27 European countries, taking into account the incidence of dengue in the exporting countries, travel volume and the probability of being viremic at the time of travel. Our models estimate a range from zero to 167 air passengers who are dengue-viremic at the time of travel from dengue endemic countries to each of the 27 receiving countries in one year. Germany receives the highest number of imported dengue-viremic air passengers followed by France and the United Kingdom. Our findings estimate 10 autochthonous secondary asymptomatic and symptomatic dengue infections, caused by the expected 124 infected travelers who arrived in Italy in 2012. The risk of onward transmission in Europe is reassuringly low, except where Aedes aegypti is present. ; HealthTheme of the Seventh Framework Programme of the European Community ; project ZikaPLAN - European Union's Horizon research and innovation programme ; International Research Consortium on Dengue Risk Assessment Management and Surveillance (IDAMS) (European Commission) ; Univ Sao Paulo, Sch Med, Sao Paulo, Brazil ; London Sch Hyg & Trop Med, London, England ; Univ Derby, Coll Nat & Life Sci, Derby, England ; Fundacao Getulio Vargas, Sch Appl Math, Rio De Janeiro, Brazil ; Fundacao Oswaldo Cruz, Programme Sci Computat, Rio De Janeiro, Brazil ; Univ Fed Sao Paulo, Hosp Sao Paulo, Escola Paulista Med, Sao Paulo, SP, Brazil ; St Michaels Hosp, Li Ka Shing Knowledge Inst, Toronto, ON, Canada ; Umea Univ, Dept Publ Hlth & Clin Med Epidemiol & Global Hlth, SE-90185 Umea, Sweden ; Harvard Med Sch, Boston, MA USA ; Boston Childrens Hosp, Boston, MA USA ; Univ Oxford, Dept Zool, Oxford, England ; Heidelberg Univ, Inst Publ Hlth, Heidelberg, Germany ; Nanyang Technol Univ, Lee Kong Chian Sch Med, Singapore, Singapore ; Univ Fed Sao Paulo, Hosp Sao Paulo, Escola Paulista Med, Sao Paulo, SP, Brazil ; PEC: 282589 ; ZikaPLAN: 734584 ; IDAMS: 21803 ; Web of Science

A cross sectional study was performed between June 2009 and March 2010 to determine the situation of bovine tuberculosis (bTB) in Rondônia. The state was divided into three regions and, in each of them, 300 farms with reproductive activity were randomly chosen and considered as primary sample units. In the selected farms, an epidemiologic questionnaire was applied. A fixed number of bovine females older than two years of age was randomly selected and tested through comparative cervical tuberculin test. Considering the State of Rondônia, the apparent prevalence of bTB positive farms was 2.3% (95% CI = 1.5–3.5%). The prevalence in the regions varied from 1.7% (95% CI = 0.7 – 4%) to 3% (95% CI = 1.6–5.7%). The apparent prevalence of bTB positive animals in the State of Rondônia was 0.12% (95% CI = 0.06–0.25%) and varied from 0.08% (95% CI = 0.04–0.18%) to 0.15% (95% CI = 0.07–0.33%) in the regions. The risk factor associated to tuberculosis in the State of Rondônia was the acquisition of animals (OR = 7.1; 95% CI = 1.6–31.1). The State of Rondônia should implement a surveillance system to detect bTB-infected herds to certify them as bTB-free. Moreover, an efficient health education program to inform farmers to test replacement animals for bTB prior to introduction in their herds should also be implemented.

The aims of the present study were to compare centrality and other measures of bovine movement networks in the state of Mato Grosso, Brazil, in 2007, by examination of the positive and negative herds identified in the brucellosis survey conducted in 2003. In addition, we aimed to examine the association between herd size (measured by the number of females older than 24 months, denoted FEM24+) and animal trade between herds. We found a statistical association between brucellosis occurrence and both the total degree (number of traded animals) and out-degree (for the number of animals sold and the number of neighboring herds). This finding suggests that positive herds in the 2003 survey were trading (particularly selling) more frequently in 2007 than negative herds, thereby presumably increasing the risk of disease spread. Statistical differences observed (p-values) in the network of movements for reproduction purposes were more significant than those observed in other networks for average herd size; degrees of animals, batches, and neighbors; outdegree of neighbors; and betweenness. We found positive associations (p < 0.001) between the following variables: number of traded animals and the FEM24+ herd size; FEM24+ herd size and FEM24+ herd size of neighbors within the network of cattle movement; FEM24+ herd size of neighbors and number of traded animals; and weighted degree (animals) of neighbors and degree (animals) of the herd of origin. A comparison of positive and negative herds stratified by herd size (? 10 FEM24+; 11-50 FEM24+; and > 50 FEM24+), within the network of movements for reproduction purposes, revealed significant differences (p < 0.05) in the > 50 FEM24+ category only, for average herd size, total degree (animals, batches, and neighbors), outdegree (animals, batches, and neighbors), and outcloseness. Logistic regression analysis, in which average herd size and degree (animals) were both factors, showed that a tenfold increase in herd size and the number of animals traded would lead to an increased chance of a herd being positive by 41% (OR = 1.41 [1.01; 1.99]) and 39% (OR = 1.39 [1.05; 1.85]), respectively. We concluded that the presence of bovine brucellosis is associated with a larger herd size, which is consistent with other reports. We also found an association between the increased trade of bovines and the presence of bovine brucellosis. Furthermore, an association was noted between herd size and animal trade, both of which could contribute to the spread of brucellosis.

A study was conducted to verify that the State of Santa Catarina has maintained a low prevalence of bovine brucellosis, which would allow the state to move forward with implementing strategies for disease eradication. The state was divided into five regions. In each region, a predetermined number of randomly selected properties was sampled. In each property, blood samples were collected from randomly selected cows with ages equal to or greater than 24 months. Sera from the animals were submitted to a serial testing protocol, with screening by the buffered acidified antigen test and confirmation by the 2-mercaptoethanol test. In each property, a questionnaire was used to identify the risk factors associated with the disease. In the state, the prevalence rate of infected herds was 0.912% [0.297 - 2.11] and infected animals was 1.21% [0.09 - 4.97]. Relative to the earlier study in 2002, there was no difference. The risk factors associated with the condition of a herd infected with brucellosis were as follows: herd size ? 12 cows (OR = 7.47 [2.14 - 34.34]) and the presence of flooded areas (OR = 5.68 [1.62 - 26.13]). In view of the low prevalence, it is recommended that the state proceed with the implementation of eradication strategies that are based on a surveillance system structured to detect and eliminate infected herds, and supported by an effective compensation fund for the replacement of seropositive animals. Additionally, the State should make a significant effort to educate and supervise producers to ensure the testing of breeding animals for brucellosis before introducing them into their properties.

In 2009, the epidemiological situation of bovine tuberculosis was studied in the state of Mato Grosso, which is a traditional beef exporter. The state was divided into four regions. In each region, properties were selected randomly. A predetermined random number of animals were chosen from these properties, and comparative cervical tuberculin tests were conducted. In total, 28,878 animals from 1,133 properties underwent examination. The animals with inconclusive results were reexamined with the same diagnostic procedure in a minimal interval of 60 days. In each sampled property, a questionnaire-based survey was conducted to identify possible risk factors for the disease. In the state, the prevalence of infected herds and animals was 1.3% [0.7; 2.4] and 0.12% [0.03; 0.44], respectively. Further, the prevalence of infected herds and animals were 0.0% [0.0; 2.0] and 0.0% [0.0; 0.08] in the Pantanal region, 1.3% [0.5; 3.1] and 0.04% [0.01; 0.17] in the dairy region, 0.7% [0.2; 2.7] and 0.01% [0.003; 0.04] in the fattening region, and 1.7% [0.7; 4.1] and 0.24% [0.06; 0.90] in the breeding region, respectively. It was observed that the condition of the herds infected with bovine tuberculosis was associated with milk production, European or mestizo breeds, degree of sophistication in the production mode, and herd size of up to 486 animals. Therefore, the implementation of a monitoring system for detection and elimination of the residual infected herds along with incorporation of risk-based monitoring elements is the best strategy for the state.

In light of recent efforts in Brazil to increase B19 strain vaccine coverage of heifers, this study proposes a standardized methodology for the calculation of vaccination coverage among the Federal Units. To illustrate its use, the method was applied to data from the state of Mato Grosso to calculate vaccination coverage from 2006 to 2010. The results provide the best estimate based on data currently available in most states and can be easily adapted to situations in which the cattle registries use different age categories from those used in the state of Mato Grosso.

The study was carried out to evaluate the effectiveness of the vaccination program against bovine brucellosis, implemented by the State of Rondônia, using prevalence rates as an indicator. The State was divided into three regions. For each region, a pre-determined number of herds were selected and at each herds, blood samples were collected from randomly chosen females with 24 months age or more. Sera from animals were submitted to a serial testing protocol, with screening performed using the buffered acidified antigen test and confirmation by the complement fixation test. A epidemiological questionnaire was administered to each farm property to identify the risk factors associated with the disease. The prevalence rates of infected herds and infected animal at the state were 12.3% [10.3–14.6] and was 1.9% [1.4–2.5], respectively. Between the regions, the prevalence of infected herds varied from 11.6% to 12.8% and the prevalence of infected animals ranged between 1.4% and 2.6%. Bovine brucellosis in Rondônia State is associated with the beef herd, a larger number of cows and the presence of flooded pastures. There was an important reduction in prevalence rates of infected herds and infected animals since 2004, however further reduction could still be achieved with vaccination. Thus, the State should continue its vaccination program, placing emphasis on ensuring the quality of the process. In addition, it should also promote the use of a vaccine that does not induce antibody formation. Additionally, the State must carry out a great effort of education so that producers test breeding animals for brucellosis before introducing them onto their properties and, where possible, prevent calved cows from having access to areas that are flooded.

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.