Epidemiological Surveillance in Wildlife Animals

Las enfermedades infecciosas zoonóticas «EMERGENTES» se han convertido en la actualidad en una de las amenazas más complicadas para la salud pública. Según la Organización Mundial de Salud Animal – OIE, aproximadamente el 75 % de las enfermedades que han surgido durante las últimas décadas tienen su origen en la fauna silvestres. Las mayores epidemias como son Hantavirus trasmitido por roedores, Nipa virus por murciélagos, Virus del Oeste del Nilo por aves, Rabia por murciélagos hematófagos, Fiebre amarilla por primates, Arenavirus por roedores y primates no humanos, Síndrome Agudo Respiratorio Severo (SARS) por murciélagos, Influenza Aviar por aves silvestres, Hendra virus por murciélagos y una larga lista adicional de enfermedades, demuestran la importancia de las enfermedades emergentes en todo el mundo y el relevante papel de los servicios veterinarios oficiales. Para vigilar estas enfermedades es preciso disponer de un equipo de trabajo multidisciplinar, con profesionales formados en medicina, epidemiología, virología, zoología y veterinaria, por la gran interrelación de factores.

Historically, wildlife disease research has been a natural part of wildlife management in some countries, for example in Europe and North America, while other countries around the world only conduct such research to safeguard the economic viability of domestic animal production systems. With the decline in wild habitats and the increase in the number of threatened species worldwide, the ability to investigate wildlife diseases must now be an essential component of wildlife management. Individual diseases or disease clusters are now recognized as important threatening processes that are leading wildlife locally to critical decline and even extinction. The definition of diseases that have an impact on threatened wildlife is now considered an integral part of rehabilitation programmes for remaining wildlife populations and captive breeding programmes designed to recover and reintegrate healthy animals into the wild. These captive breeding programmes are carried out within the framework of a conventional zoological collection.

Information on the presence of infectious, parasitic and toxic diseases in wildlife is essential to local and global understanding of wildlife populations. Too often, only a small part of this research is published in technical or scientific journals. Most, if not all, of the annual records of diagnostic laboratories are never published and therefore remain hidden from those concerned about the emergence of emerging diseases in another part of the world. Therefore, the establishment of national and regional monitoring programmes for wildlife disease surveillance is essential to ensure a minimum level of reporting and circulation of this information, and infrastructures to support wildlife disease outbreak research and wildlife health programmes should be comparable or equal to those of domestic animal species.

In fact, all scientific disciplines and technologies available in veterinary diagnostic laboratories would support such programmes, and the development of local networks would also necessarily include epidemiological and zoological inputs to support such disease surveillance and diagnostic studies. A monitoring programme based on regular disease investigations and post-mortem examination will, after a few years, provide a basic understanding of the types of diseases that occur in certain geographical regions or in certain animal species and populations. The archive of laboratory cases, attached to stored serum and tissue samples, will be invaluable for retrospective investigations of new or newly emerging diseases. If new diseases (mortality/morbidity events) occur, they are likely to be discovered most of the time through passive programs based on laboratory access and post-mortem examinations.

Es imprescindible, por tanto, que los servicios veterinarios oficiales evalúen o estimen el riesgo que implica «el no tener» un programa de vigilancia epidemiológica en animales silvestres, el riesgo de no contar con un programa en fauna silvestre incrementa sin lugar a dudas el riesgo de la emergencia y reemergencia de enfermedades de importancia para la salud pública.

WILLIAM VALDERRAMA PhD