Risk evaluation of nonvaccinated, weaned calves transported through areas under systematic foot and mouth disease (FMD) vaccination.

The recurrence and persistence of foot and mouth disease (FMD) could be the consequence of cyclic and massive transportation of calves. For this reason, in South America, vaccination strategies related to livestock dynamic are being promoted. In order to aid the evaluation of such strategies, a method for predicting the risk of transportation of nonvaccinated weaned calves was developed; this method combines expert opinion and empirical evidence using Bayesian estimators. It was applied through Monte Carlo simulation to data of Argentina under four hypothetical vaccination schemes: E1, extended vaccination season of 1/6 of the population of calves each month from July to December without second round vaccination (SRV); E2, extended irregular vaccination from July to December with SRV applied to 70% of the calves resembling the scheme applied in Argentina in 2001; E3, vaccination in November and December without SRV; and E4, vaccination concentrated in November. E1 resulted in probability of transporting non vaccinated calves (tnvc) reaching its maximum in the following year in May with mean=0.0250 and percentile 95% (P95)=0.0404; for the same month tnvc estimates for the other schemes were E2: mean=0.0071; P95=0.0162; E3: mean=0.0017; P95=0.0042 and E4: mean=0.0001; P95=0.0004. Bonferroni multiple comparison for simultaneous assertions for May showed that E4 resulted the best scheme, E1 the worst, and E2 and E3 are intermediate with nonsignificant difference observed between overall (p<0.05). Results were consistent with historical records and quantification for future needs for re-vaccination was made possible. While the ratio "total vaccinated"/"total estimated existences" will give a biased vision of vaccination coverage under the situation of extended vaccination campaigns, a model as the one developed here could allow a more accurate assessment and the design of mitigation plans.

Overview of rabies in the Americas.

Between 1993 and 2002, the number of human and canine rabies cases in the Americas Region fell by approximately 80%. There were 39 human cases in 2002, 63% of them transmitted by dogs. Furthermore, human rabies transmitted by wildlife, mostly by bats is a risk to inhabitants in many countries in the Region. The objective of this study is to describe this epidemiological situation based in the information received from the countries of the Americas Region in Regional Rabies Surveillance System in the Americas (SIRVERA) administrated by the Pan American Health Organization. This sharp reduction is attributable mainly to the control measures implemented by the countries of the Region, such as the mass vaccination of dogs and prophylactic treatment for people who have been exposed.

Emerging diseases and their impact on animal commerce: the Argentine lesson.

As a result of the Argentine experience with foot-and-mouth disease (FMD) in 2001, a need was postulated for the establishment of efficient supranational schemes for continuous surveillance of the interrelations between tropical extractives livestock systems and the prairies that are optimal for the feeding of livestock in the southern region of South America. FMD in Argentina and in other countries, new or re-emerging risks from avian influenza with potential risks for public health, the spongiform encephalopathies, porcine reproductive and respiratory syndrome, and classical swine fever, among other animal diseases, have generated a strong reaction and evolution within the veterinary services of the country. These present lessons will influence decision-making within countries and should be accepted by the technical and scientific community. From the perspective of the official animal health sector and with the FMD eradication plan as a basis within the national territory, we have worked not only to achieve international recognition and credibility within animal health systems, but also to realize the formation of a regional block of countries that can be recognized internationally as an area with equivalent animal health status. We emphasize not only that this lesson is useful in FMD, but also that it is possible to apply the valuable conclusions reached for other emerging or re-emerging diseases.

BSE: el analisis de riesgo como herramienta para definir la prevención y vigilancia de los factores de riesgo en pais libre de la enfermedad

Se presenta un esquema de prevención y vigilancia de las encefalopatías espongiformes transmisibles tendiente a: mantener la condición de país libre de BSE; mantener actualizado el análisis y seguimiento de los factores de riesgo externo e interno respecto de las TSE; certificar con máxima precisión la condición sanitaria respecto de las TSE del país y de los productos destinados al mercado interno y a la exportación.

[Prevention of and attention to emergencies in South America]. / Prevención y atención de emergencias en sudamérica.

The authors review the policies designed to prevent and deal with animal health emergencies which have been implemented in countries of South America. They describe the evolution of the epidemiological situation of the continent, the new arrangements for international trade in animals and products of animal origin arising from the creation of the World Trade Organization (WTO), and the consequences of such developments for livestock production in South America. Veterinary systems used to prevent and deal with emergencies in the eleven OIE Member Countries on the continent are described, together with emerging problems which confront the Veterinary Services of the continent, namely: exotic diseases, abnormal occurrence of endemic diseases subject to control programmes, faults in food-safety mechanisms, diseases which have an environmental impact, and problems connected with animal welfare. The emergencies which present the greatest risk to South America are foot and mouth diseases, transmissible spongiform encephalopathies, the porcine reproductive and respiratory syndrome, food poisoning, Newcastle disease and fowl plague. Other problems are the appearance of new strains of existing agents, and the presence of resistant individuals among species of bacteria or harmful arthropods. The authors emphasise the need to co-ordinate the prevention of emergencies with development work at the international level, particularly regional and international agreements, harmonization of procedures, progress in animal health and public health, risk analysis, etc. These systems and methods of prevention have a contribution to make in enhancing the potential of animal production in South America, and the adoption of stricter health and quality standards, according to criteria established by the WTO Agreement on the Application of Sanitary and Phytosanitary Measures.

Quantitative risk analysis applied to innocuity and potency tests on the oil-adjuvanted vaccine against foot and mouth disease in Argentina.

The authors describe the method used in Argentina for quantification of risk in controls of the potency and innocuity of foot and mouth disease vaccine. Quantitative risk analysis is a relatively new tool in the animal health field, and is in line with the principles of transparency and equivalency of the Sanitary and Phytosanitary Agreement of the Uruguay Round of the General Agreement on Tariffs and Trade (GATT: now World Trade Organisation [WTO]). The risk assessment is presented through a description of the steps involved in manufacturing the vaccine, and the controls performed by the manufacturer and by the National Health Animal Service (Servicio Nacional de Sanidad Animal: SENASA). The adverse situation is considered as the lack of potency or innocuity of the vaccine, and the risk is estimated using a combination of the Monte Carlo simulation and the application of a Bayesian model.