No abstract

The Integrated Disease Surveillance and Response (IDSR) strategy was developed by the Africa Regional Office (AFRO) of the World Health Organisation (WHO) and proposed for adoption by member states in 1998. The goal was to build WHO/AFRO countries' capacity to detect, report and effectively respond to priority infectious diseases. This evaluation focuses on the outcomes in four countries that implemented this strategy. Major successes included: integration of the surveillance function of most of the categorical disease control programmes; implementation of standard surveillance, laboratory and response guidelines; improved timeliness and completeness of surveillance data and increased national-level review and use of surveillance data for response. The most challenging aspects were: strengthening laboratory networks; providing regular feedback and supervision on surveillance and response activities; routine monitoring of IDSR activities and extending the strategy to sub-national levels.

Despite early attempts to control the spread of the disease, porcine reproductive and respiratory syndrome (PRRS) has now become endemic in many countries including Britain. The occurrence of subclinical herd infections, the prolonged circulation of virus within herds and probable aerogenic virus spread all mitigated against the success of control measures. The origin of the disease is unknown but the causative agent has been shown to be an arterivirus with shared features to lactate dehydrogenase virus of mice. There is evidence of extreme genetic and antigenic variability between American and European isolates. PRRS virus has a predilection for alveolar macrophages and does not grow in most cell lines. In infected pigs, viraemia can persist for many weeks in the face of circulating antibodies and little is known about the mechanisms by which immunity to infection develops. A wide spectrum of disease has been reported from the field, accompanied in some cases by heavy economic losses. Reproductive and perinatal losses were most prominent when the disease first appeared. In the endemic phase, PRRS may be more significant as a contributory factor to a post-weaning respiratory syndrome of young pigs of 3-8 weeks. On-farm techniques have been developed to reduce the recycling of PRRS virus from older infected nursery pigs to the younger newly weaned pig. Vaccines are now marketed for the control of PRRS, but are not licensed for use in Britain. Improvements in knowledge of virion composition and antigenic stability and in the nature of the immune response of the pig should result in genetically engineered subunit vaccines becoming available. Diagnosis of PRRS is still difficult as many animals do not show clinical signs and may only be detected by serology and often only when other respiratory diseases are being investigated. Now that the infection is widespread, serological testing must be properly targeted and interpreted to give meaningful results about virus circulation. An increasing arsenal of diagnostic methods are becoming available to detect virus in both fresh and fixed specimens. The pathogenic mechanisms of PRRS remain poorly defined and more work is needed to reveal the nature of the interaction between PRRS virus and other factors in disease.

In 1951 the Centers for Disease Control and Prevention created the Epidemic Intelligence Service to provide training and epidemiologic service on the model of a clinical residency program. By January 2001, an additional 28 applied epidemiology and training programs (AETPs) had been implemented around the globe (with over 945 graduates and 420 persons currently in training). Field Epidemiology Training Programs and Public Health Schools Without Walls are the most common models. Applied epidemiologists, or field epidemiologists, use science as the basis for intervention programs designed to improve public health. AETPs train people by providing them with health competencies through providing service to public health intervention programs and strengthening health systems. AETPs are relatively expensive to create and maintain, but they are highly sustainable and can produce immediate benefits. Of the 19 programs that began before 1997, 18 (95%) continue to produce graduates. The Training Programs in Epidemiology for Public Health Interventions Network was organized in 1997 to provide support, peer review, and quality assurance for AETPs. In 2001, new programs are planned or in development in India, Argentina, China, and Russia.

SYNOPSISField epidemiology training programs have been successful models to address a country's needs for a skilled public health workforce, partly due to their responsiveness to the countries' unique needs. The Centers for Disease Control and Prevention has partnered with ministries of health to strengthen their workforce through customized competency-based training programs. While desirable, emphasis on program flexibility can result in redundancy and inconsistency. To address this challenge, the ADDIE model (analysis, design, development, implementation, and evaluation) of instructional design was used by a cross-functional team to guide completion of a standard curriculum based on 15 competencies. The standard curriculum has supported the development and expansion of programs while still allowing for adaptation. This article describes the process that was used to develop the curriculum, which, together with needs assessment and evaluation, is crucial for successful training programs.