La vigilancia en el programa ampliado de inmunización / Surveillance for the expanded programme on immunization

La vigilancia es la base de la práctica de la salud pública. En este artículo se examina la experiencia de la vigilancia en el Programa Ampliado de Inmunización (PAI). Los sistemas de vigilancia incluyen la notificación regular, la vigilancia centinela y la notificación comunitaria. Los datos de las actividades de vigilancia deben vincularse a los obtenidos con la supervisión, la evaluación de centros asistenciales, encuestas de población y la investigación de brotes, con objeto de proporcionar información para la planificación, ejecución, evaluación y modificación de programas. Al evaluar los sistemas de vigilancia se debe determinar la medida en que se usan los datos para formular políticas y mejorar programas, así como la simplicidad, exactitud, integridad, puntualidad y costo de los datos. La vigilancia de las enfermedades inmunoprevenibles ha evolucionado a medida que los programas han ido madurando, para monitorear el progreso hacia las metas de control de enfermedades. La adopción de las metas de reducir los casos de sarampión en 90 por ciento, eliminar el tétanos neonatal y erradicar la poliomielitis ha puesto de relieve la necesidad de disponer de sistemas de vigilancia efectiva de las enfermedades. Es necesario aprovechar esta oportunidad para promover el fortalecimiento de los sistemas nacionales de vigilancia de las enfermedades, a fin de convertirlos en instrumentos efectivos de prevención y control de enfermedades importantes para la salud pública (AU)

Publicado en inglés en: Bull. WHO. Vol. 71(5), 1993

Cholera in Africa: lessons on transmission and control for Latin America.

In January, 1991, epidemic cholera emerged in Peru and spread to 7 other countries of Latin America. Cholera was introduced 20 years ago to Africa, where it spread rapidly to 30 of the 46 countries of the region and by 1990 accounted for 90% of all cases reported to the World Health Organisation. Many lessons from the cholera epidemic in Africa are relevant to efforts to control the disease in Latin America. Public health practices from the past--quarantine and cordon sanitaire to halt introduction of cholera by travellers, and vaccination and mass chemoprophylaxis to control epidemics--are ineffective in preventing spread of the disease. Cholera can be transmitted not only by contaminated water but also by food. Social phenomena such as mass migrations and burial practices may play a greater role than previously understood. While efforts to prevent the spread of cholera have been ineffective, cholera-associated mortality can be decreased with rehydration therapy. Since the current pandemic is unlikely to retreat soon, new strategies are urgently needed to control the spread of cholera through sanitary and behavioural interventions or improved vaccines.

PIP: Latin America had been free of cholera for 70 years until January 1991 when the 7th pandemic of El Tor cholera struck Peru. It killed 1500 people and affected 200,000 people within 6 months. It soon spread to at least 7 other Latin American countries. 20 years earlier the it reached Africa. Foci of infections in Africa included markets, fairs, funerals, and refugee camps. Scientists doubted that vaccination or quarantine would have prevented its introduction into Africa. Yet, in Latin America, public health officials should earnestly reconsider chemoprophylaxis (tetracycline) of family contacts in families with high rates of illness. Presently no such data exist in Latin America. In addition, health workers should test the new oral vaccine in Latin America since there is no preexisting immunity and the people are exposed to high levels of contamination. Little epidemic research was done in Africa to pinpoint modes of transmission so health workers could learn what types of intervention were warranted. It should be done in Latin America, however. As for quarantine, symptomatic and mild to moderate cholera cases can outnumber severe cases as much as 100 to 1, so confining cases would not prevent the spread of the disease. Latin America should broaden diarrheal disease control programs to include adults so they will accept oral rehydration therapy (ORT). It should be used in mild to moderate dehydration cases and intravenous rehydration therapy for severe cases. If the environmental factors are not known and understood and if feces contaminate water supplies, foods, and fisheries, cholera may become endemic in Latin America. In conclusion prompt disease reporting, surveillance, and implementation of control measures could prevent the endemicity of cholera in Latin America.

Prevention of excess mortality in refugee and displaced populations in developing countries.

More than 30 million refugees and internally displaced persons in developing countries are currently dependent on international relief assistance for their survival. Most of this assistance is provided by Western nations such as the United States. Mortality rates in these populations during the acute phase of displacement have been extremely high, up to 60 times the expected rates. Displaced populations in northern Ethiopia (1985) and southern Sudan (1988) have suffered the highest crude mortality rates. Although mortality rates have risen in all age groups, excess mortality has been the greatest in 1- through 14-year-old children. The major causes of death have been measles, diarrheal diseases, acute respiratory tract infections, and malaria. Case-fatality ratios for these diseases have risen due to the prevalence of both protein-energy malnutrition and certain micronutrient deficiencies. Despite current technical knowledge and resources, several recent relief programs have failed to promptly implement essential public health programs such as provision of adequate food rations, clean water and sanitation, measles immunization, and control of communicable diseases. Basic structural changes in the way international agencies implement and coordinate assistance to displaced populations are urgently needed.

Prevención y control del sarampión en situaciones de emergencia / Prevention and control of measles in emergency situations

Prevention and control of measles in emergency situations

Se publica en ingles en el Bull. WHO 67(4), 1989