Bovine Brucellosis in Argentina and Bordering Countries: Update

Abstract

Bovine brucellosis is a zoonotic disease spread worldwide. The infection in cattle is predominantly caused by Brucella abortus and is usually detected in pregnant females through abortions. The disease is endemic in Argentina; however, infection in humans is underestimated and often not reported. The prevalence of bovine brucellosis in countries bordering Argentina is quite variable: 0.04% in Uruguay, 10.20% in the north and 0.06% in the south of Brazil, 0.2% in Chile, 3.15% in Paraguay and 2.27% in Bolivia. In 1999, the Argentine National Control and Eradication Program was implemented. Its strategies include identification of vaccinated animals, compulsory vaccination with B. abortus S19 of 100% of 3- to 8-month-old females, negative serological tests before animal movements and categorization of farms in terms of their brucellosis status. The epidemiological surveillance in milk is performed through the milk ring test and the indirect ELISA. The result of a national brucellosis survey performed in 2004 indicates that 12.4% (95% CI: 10.89-14.0) of Argentine beef farms are seropositive to Brucella and that the apparent prevalence in cattle is 2.10% (95% CI: 1.90-2.40). The official serological diagnostic tests are as follows: buffered plate antigen test, as screening, serum agglutination test, 2-mercaptoethanol and fluorescence polarization assay, competitive ELISA, as confirmatory tests, and complement fixation test, as definitive test. Santa Fe and a district in Córdoba have 'Outstanding Plans'. Tierra del Fuego is a 'Zone free from bovine brucellosis'. One question arising when studying the Argentine situation is why the disease remains endemic if good regulations exist to control and eradicate it. In future, some different aspects might be evaluated to understand it, and further studies should be performed to prioritize, select and refine control strategies.

Vaccination with a ΔnorD ΔznuA Brucella abortus mutant confers potent protection against virulent challenge

“…Despite their availability, conventional brucellosis vaccines are only approximately 70% efficacious [24, 25]. Although the smooth vaccine, B. abortus S19, has been replaced with the rough RB51 vaccine in the US [26], S19 is still used in many countries including India [27] and Argentina [28]. S19 tends to be more pathogenic and can cause abortion in 3.2% of pregnant cows following subcutaneous vaccination [29] or 100% following i.v.…”

Screening food-borne and zoonotic pathogens associated with livestock practices in the Sumapaz region, Cundinamarca, Colombia

“…Epidemiological surveillance is important because the commercialization of unpasteurized dairy products can pose a threat to human public health. In addition, zoonotic infections, such as brucellosis and TB, are common, insidious, and persistent problems for livestock farmers in general in developing countries (Aznar et al 2014; Roess et al 2015). Despite control measures and sanitation efforts, zoonotic disease outbreaks have been reported in Colombia (Morales and Combariza 2004; González et al 2007; Tique et al 2009, 2010).…”

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

“…Other countries, such as Canada and the United States, still have some cases, which are directly connected to infections in wild animals (RAGAN, 2002;OIE, 2014). In various South American countries, sero-epidemiologic studies have demonstrated a large variation in the apparent prevalence of cattle seropositive for B. abortus, albeit differences in geographical stratification and methodologies; from 2.10% in Argentina (AZNAR et al, 2014(AZNAR et al, ), 3.15% (2000 to 1.62% (the first six months of 2014) in Paraguay (BAUMGARTEN, 2002;SENACSA, 2014), 1.22% in Bolivia (MANRIQUE et al, 2005), 0.2% in Chile (LOPETEGUI, 2011), and 0.04% in Uruguay (GARIN, 2011).…”