Methods for Trapping and Sampling Small Mammals for Virologic Testing

Despite the tremendous medical progress made since the middle of this century, infectious diseases remain the leading cause of death among humans worldwide. Many infectious diseases have long been recognized as threats to human health; others, the “emerging” diseases, have been identified only recently. A substantial number of these diseases are classified as zoonoses because animals are their natural reservoirs.

The continued human encroachment upon and alterations of natural ecosystems will likely result in more frequent encounters with animal reservoirs of recognized pathogens as well as encounters with previously unknown infectious agents. One of the most important tools in identifying and minimizing the impact of infectious disease outbreaks is intensive and continuous surveillance. In the case of zoonotic diseases, surveillance can be carried out by monitoring reservoir populations. Data collected on infection prevalence and population characteristics of reservoir species can be used to assess risk to humans and ameliorate or prevent outbreaks of human disease.

This manual is intended as a guide for those persons performing ecologic and epidemiologic studies involving populations of rodents which are potentially infected with hantavirus. However, the procedures outlined are appropriate for any study of small-mammal populations that may harbor an infectious zoonotic agent capable of causing severe disease or death. The manual covers the following major topics in detail: selection of appropriate collection sites; trapping methods that provide a representative sample of the rodent population; handling, operation, and placement of traps for small mammals; safe and humane techniques for trapping and handling rodents; selection of appropriate sample fluids and tissues and detailed methods for obtaining these samples; proper storage, packaging and shipment of specimens to the laboratory; effective decontamination and cleaning of traps and other materials; safe disposal of infectious wastes; and careful collection and recording of all pertinent data. The manual is illustrated with black and white photos to assist the trainee in understanding these techniques. Sample forms are provided in appendices and can be adapted to specific programs by users.