A new test developed by Embrapa will widen the coverage of bovine tuberculosis diagnosis in dairy cattle and beef herds. The serologic testing named Elisa, abbreviation for enzyme-linked immunosorbent assay, gives additional information to traditional methods of detection, which can provide false-positive and false-negative reactions due to bacillus characteristics and animal conditions. Its effectiveness ensures isolation and slaughter of sick cattle, saving the rest of herd, as the disease is infectious and there is still no cure. The tool will be efficient for the official services of health protection and for rural producers, as well as will ensure sanity on the property. Currently being finalized, Elisa will be available soon by partnering with the private sector. The key to higher accuracy is the use of parts of three recombinant proteins, whereas the commercial kit so far in use has only two proteins. Elisa was obtained after attempts comprising more than ten compositions in studies initiated in 2009, and in field trials, it could identify infected cattle that were not flagged by the product available until then, showing a sensitivity of 83.2% and specificity of 86.5 %. The Embrapa researcher Flábio Ribeiro de Araújo explains that antibodies against proteins are produced at different times, depending on the stage of infection in cattle and buffaloes, and the Elisa kit can detect the disease at different levels. During the research, it was possible to correctly trace 88.7% of infected animals and 94.6% of healthy animals. There is another advantage regarding manufacture, in which only a purification process is performed, thereby reducing costs for the industry. The standard diagnostic tool used in Brazil, the tuberculin test, is performed using cellular immunity tests in vivo more specifically intradermal tests with PPD (purified protein derivative). The tuberculin is injected under the animal skin and 72 hours after the inflammatory reaction the result can be read. The procedure detects the called cellular immune animal response to infection by M. bovis. However, this is not the only response produced in order to face an infection, explains Araújo. "Animals also respond producing antibodies against the bacteria, and part of them can not respond to intradermal tests, especially those in advanced stages of disease with large lesions. In this situation, the disease is not detected and the animals remain infected within the properties." Factors such as recent infections, final gestation period, malnutrition and anti-inflammatory drugs treatment also cause false-negatives. Rodrigo Nestor Etges, a veterinarian and agricultural supervisor of the Rio Grande do Sul Secretariat of Agriculture, has been applying the new method on farms where tuberculosis outbreaks were registered. He confirms that it is common reagent animals fail to respond to tuberculin and produce false-negatives, making sanitation difficult. The staff of Animal Health Protection Department, of which the specialist is part, accompanies positive sera by test developed by Embrapa in search of false-negatives. According to the professional, blood samples obtained so far are encouraging. Etges believes the kit will streamline sanitary procedures and should generate significant progress in combating the disease. The bacillus affects production of beef cattle, however, it affects predominantly dairy cattle and this generates a social drama, according to technician. "Dairy farmers of Rio Grande do Sul are small producers who have an average of 15 dairy cows per property. An outbreak can be dramatic and the disposal of animal involves daily loss of production and income", warns Etges. "The situation worsens when a producer has to do the fallowing, discarding his herd and only later reconstruct it. Often milk is the only source to the family income", adds Araújo. An alert for public health Tuberculosis is a disease of chronic progression caused by Mycobacterium bovis bacteria and affects cattle, goats, sheep, pigs, wild animals and humans, which characterizes it as zoonosis. The most common form of transmission is by air, corresponding to almost 90% of infections. The scenario is a reason of concern when related to biological safety of food. In some tests carried out by Flábio Araújo and Rodrigo Etges, the milk contaminated with M. bovis was consumed normally by some farm owners and their families, who did not know the presence of microorganism. The World Health Organization (WHO) estimates an increase of 500 thousand new cases of multidrug-resistant tuberculosis (MDR-TB) each year in the world, which represents 5% of the nine million cases annually. The World Health Organization believes that M. bovis infection in humans contributes to increasing cases of MDR-TB. "In Brazil, there is not an exact estimate of the zoonotic tuberculosis incidence. An Embrapa study published by Instituto Oswaldo Cruz found cases in 2014", said the corporation researcher Márcio Roberto Silva. Presence in national herds is also a hindrance to handmade products made from raw milk, such as cheese. A basic prerequisite for producing them is the negative clearance from both tuberculosis and brucellosis properties. "However, accomplishing such a condition for these two diseases, certifying it and, above all, maintaining it, are not simple tasks", says Silva, noting that the new tests collaborate to the advancement of stages in diagnosis, eradication and monitoring. In his doctorate, the researcher proved the existence of human cases associated with consumption of artisan cheeses, in Juiz de Fora (MG). The Tuberculosis Commission coordinator from the Brazilian Society of Thoracic Association (BTA), Eliana Matos, explains that Mycobacterium tuberculosis, Koch's bacillus, and Mycobacterium bovis belong to the same complex of mycobacteria, being genetically similar each other, which hampers the diagnosis and overloads the daily practice of a hospital. "Every year we have 70 thousand new cases of human tuberculosis in Brazil. We would need highly specialized exams for genetic sequencing and differentiation, exams that are not done in the routine. That would be unviable and expensive, from a practical point of view." However, for occurrences concerning epidemiological links, such as fresh milk intake and soon after the onset symptoms, the pulmonologist considers the reference laboratories in the country, as Professor Hélio Fraga Reference Center (RJ) and Instituto Adolfo Lutz (SP), both able to recognize precisely individualizing the situation. Working in public health, Eliana considers fundamental the monitoring, control of animal origin products and prevention. To Márcio Roberto Silva, when thinking about zoonosis, the way forward is to focus on the concept of "One Health" global approach to different aspects of the problem. Several Embrapa research centers have been working in this discussion to combat M. bovis. Preventing is the best way to combat tuberculosis Flábio stresses that the new kit is limited, but will provide additional information, identifying animals not detected by standard examination and increasing the coverage of the diagnosis. The ideal for this diagnosis would be to adopt complementary technologies such as tuberculin test along with the serological as Elisa. A risk for the market In Brazil, Mato Grosso is moving towards eradication of tuberculosis, but the prospect is not the same in other states. In line with the supranational organizations of which Brazil is signatory, the Ministry of Agriculture, Livestock and Food Supply (Mapa) adopts National Programs to control and eradicate animal diseases with a public health impact. "Bovine tuberculosis and bovine brucellosis are among the diseases included in the OIE list and have features like wide spread and importance to the economy and public health", said Jorge Caetano Junior, federal tax farming of Mapa and Sanitary Standards Committee member for Terrestrial Animals of the World Organization for Animal Health (OIE). "In 1978, Maple food scraps originated from a flight to Rio de Janeiro allowed the entry of the African swine fever on national territory causing injury to production and marketing of swine-origin products nationwide and consuming tens of millions of dollars in public funds for its eradication, finished three years later", recalls Caetano. The specialist says that "the loss of the health condition of animals or their products, even if temporary, can result in huge loss to the national livestock patrimony, with economic and social consequences of great magnitude which can not be restricted to the sector." Flábio Araújo points out that the main strategy for producers is monitoring with periodic diagnostics, which "minimizes risk but does not eliminate it. An infected animal remains contaminating the others, even though it does not present a positive intradermal reaction", says the veterinarian. Preventive measures begin by management, hygiene, transportation, extra care with the entry of new lots in the farm and follow the rules described in the rules of the National Control and Eradication of Brucellosis and Tuberculosis Animal Plan (PNCEBT). Brazil has the second largest cattle herd in the world, comprising about 200 million head and, since 2004, took the lead in exports to a fifth of internationally traded meat and sales in more than 180 countries.
A new test developed by Embrapa will widen the coverage of bovine tuberculosis diagnosis in dairy cattle and beef herds. The serologic testing named Elisa, abbreviation for enzyme-linked immunosorbent assay, gives additional information to traditional methods of detection, which can provide false-positive and false-negative reactions due to bacillus characteristics and animal conditions. Its effectiveness ensures isolation and slaughter of sick cattle, saving the rest of herd, as the disease is infectious and there is still no cure. The tool will be efficient for the official services of health protection and for rural producers, as well as will ensure sanity on the property. Currently being finalized, Elisa will be available soon by partnering with the private sector. The key to higher accuracy is the use of parts of three recombinant proteins, whereas the commercial kit so far in use has only two proteins.
Elisa was obtained after attempts comprising more than ten compositions in studies initiated in 2009, and in field trials, it could identify infected cattle that were not flagged by the product available until then, showing a sensitivity of 83.2% and specificity of 86.5 %. The Embrapa researcher Flábio Ribeiro de Araújo explains that antibodies against proteins are produced at different times, depending on the stage of infection in cattle and buffaloes, and the Elisa kit can detect the disease at different levels. During the research, it was possible to correctly trace 88.7% of infected animals and 94.6% of healthy animals. There is another advantage regarding manufacture, in which only a purification process is performed, thereby reducing costs for the industry.
The standard diagnostic tool used in Brazil, the tuberculin test, is performed using cellular immunity tests in vivo more specifically intradermal tests with PPD (purified protein derivative). The tuberculin is injected under the animal skin and 72 hours after the inflammatory reaction the result can be read. The procedure detects the called cellular immune animal response to infection by M. bovis. However, this is not the only response produced in order to face an infection, explains Araújo. "Animals also respond producing antibodies against the bacteria, and part of them can not respond to intradermal tests, especially those in advanced stages of disease with large lesions. In this situation, the disease is not detected and the animals remain infected within the properties." Factors such as recent infections, final gestation period, malnutrition and anti-inflammatory drugs treatment also cause false-negatives.
Rodrigo Nestor Etges, a veterinarian and agricultural supervisor of the Rio Grande do Sul Secretariat of Agriculture, has been applying the new method on farms where tuberculosis outbreaks were registered. He confirms that it is common reagent animals fail to respond to tuberculin and produce false-negatives, making sanitation difficult. The staff of Animal Health Protection Department, of which the specialist is part, accompanies positive sera by test developed by Embrapa in search of false-negatives. According to the professional, blood samples obtained so far are encouraging. Etges believes the kit will streamline sanitary procedures and should generate significant progress in combating the disease.
The bacillus affects production of beef cattle, however, it affects predominantly dairy cattle and this generates a social drama, according to technician. "Dairy farmers of Rio Grande do Sul are small producers who have an average of 15 dairy cows per property. An outbreak can be dramatic and the disposal of animal involves daily loss of production and income", warns Etges. "The situation worsens when a producer has to do the fallowing, discarding his herd and only later reconstruct it. Often milk is the only source to the family income", adds Araújo.
An alert for public health
Tuberculosis is a disease of chronic progression caused by Mycobacterium bovis bacteria and affects cattle, goats, sheep, pigs, wild animals and humans, which characterizes it as zoonosis. The most common form of transmission is by air, corresponding to almost 90% of infections.
The scenario is a reason of concern when related to biological safety of food. In some tests carried out by Flábio Araújo and Rodrigo Etges, the milk contaminated with M. bovis was consumed normally by some farm owners and their families, who did not know the presence of microorganism. The World Health Organization (WHO) estimates an increase of 500 thousand new cases of multidrug-resistant tuberculosis (MDR-TB) each year in the world, which represents 5% of the nine million cases annually. The World Health Organization believes that M. bovis infection in humans contributes to increasing cases of MDR-TB.
"In Brazil, there is not an exact estimate of the zoonotic tuberculosis incidence. An Embrapa study published by Instituto Oswaldo Cruz found cases in 2014", said the corporation researcher Márcio Roberto Silva. Presence in national herds is also a hindrance to handmade products made from raw milk, such as cheese. A basic prerequisite for producing them is the negative clearance from both tuberculosis and brucellosis properties. "However, accomplishing such a condition for these two diseases, certifying it and, above all, maintaining it, are not simple tasks", says Silva, noting that the new tests collaborate to the advancement of stages in diagnosis, eradication and monitoring. In his doctorate, the researcher proved the existence of human cases associated with consumption of artisan cheeses, in Juiz de Fora (MG).
The Tuberculosis Commission coordinator from the Brazilian Society of Thoracic Association (BTA), Eliana Matos, explains that Mycobacterium tuberculosis, Koch's bacillus, and Mycobacterium bovis belong to the same complex of mycobacteria, being genetically similar each other, which hampers the diagnosis and overloads the daily practice of a hospital. "Every year we have 70 thousand new cases of human tuberculosis in Brazil. We would need highly specialized exams for genetic sequencing and differentiation, exams that are not done in the routine. That would be unviable and expensive, from a practical point of view."
However, for occurrences concerning epidemiological links, such as fresh milk intake and soon after the onset symptoms, the pulmonologist considers the reference laboratories in the country, as Professor Hélio Fraga Reference Center (RJ) and Instituto Adolfo Lutz (SP), both able to recognize precisely individualizing the situation. Working in public health, Eliana considers fundamental the monitoring, control of animal origin products and prevention. To Márcio Roberto Silva, when thinking about zoonosis, the way forward is to focus on the concept of "One Health" global approach to different aspects of the problem. Several Embrapa research centers have been working in this discussion to combat M. bovis.
Preventing is the best way to combat tuberculosis
Flábio stresses that the new kit is limited, but will provide additional information, identifying animals not detected by standard examination and increasing the coverage of the diagnosis. The ideal for this diagnosis would be to adopt complementary technologies such as tuberculin test along with the serological as Elisa.
A risk for the market
In Brazil, Mato Grosso is moving towards eradication of tuberculosis, but the prospect is not the same in other states. In line with the supranational organizations of which Brazil is signatory, the Ministry of Agriculture, Livestock and Food Supply (Mapa) adopts National Programs to control and eradicate animal diseases with a public health impact. "Bovine tuberculosis and bovine brucellosis are among the diseases included in the OIE list and have features like wide spread and importance to the economy and public health", said Jorge Caetano Junior, federal tax farming of Mapa and Sanitary Standards Committee member for Terrestrial Animals of the World Organization for Animal Health (OIE).
"In 1978, Maple food scraps originated from a flight to Rio de Janeiro allowed the entry of the African swine fever on national territory causing injury to production and marketing of swine-origin products nationwide and consuming tens of millions of dollars in public funds for its eradication, finished three years later", recalls Caetano. The specialist says that "the loss of the health condition of animals or their products, even if temporary, can result in huge loss to the national livestock patrimony, with economic and social consequences of great magnitude which can not be restricted to the sector."
Flábio Araújo points out that the main strategy for producers is monitoring with periodic diagnostics, which "minimizes risk but does not eliminate it. An infected animal remains contaminating the others, even though it does not present a positive intradermal reaction", says the veterinarian. Preventive measures begin by management, hygiene, transportation, extra care with the entry of new lots in the farm and follow the rules described in the rules of the National Control and Eradication of Brucellosis and Tuberculosis Animal Plan (PNCEBT).
Brazil has the second largest cattle herd in the world, comprising about 200 million head and, since 2004, took the lead in exports to a fifth of internationally traded meat and sales in more than 180 countries.
