Field Parasitology Techniques for Use with Mammals

Obtaining parasites from mammals that are collected during surveys or bioinventories is time-consuming, and in the past such collections have rarely been made. Parasites and other symbionts are important components of the biology of the host, however, and must be sampled for a complete picture of its ecology and other aspects of its life history. For example, work on parasite diversity and biogeography of mammals in Bolivia (Gardner and Duszynski 1990; Gardner 1991: Gardner et al. 1991; Gardner and Campbell 1992a, 1992b) could not have been accomplished without proper collections of the parasite and symbiont fauna of the hosts. Many researchers are reluctant to assign one or two persons from a field crew to process parasites from mammals when the specimens and associated data are considered auxiliary or collateral. The most efficient and cost-effective method of obtaining data on the parasite fauna of a host group, however, is to collect the parasites when mammals are being processed in the field. Examples of the types of data that may be obtained when a host is collected are prevalence, intensity of infection, and distribution of parasites in or on individuals and through populations of hosts. Studies of the systematics and ecological characteristics of hosts and parasites require proper identification of both groups. If the parasites associated with a host are not collected and preserved properly, species-level diagnostic characters (i.e. morphological characters) will almost certainly be destroyed; in addition, improper preservation of parasite material will severely limit studies based on intact DNA molecules of those parasites. Problems with identification of correct hosts may occur when parasites accidentally transfer from one host to another at the time of collection. Anthropogenic host-transfer can occur anywhere and is difficult to avoid in the field. For example, ectoparasites from one host may remain in a trap after the animal is removed. Those parasites may then transfer to another host of a different species at the same or a different collecting locality. Anthropogenic host-transfers occur even more frequently when hosts are placed in a killing jar that has not been cleaned completely after each use. In this appendix, I outline methods for collecting parasites that maximize the amount of morphological and molecular information available from each parasite obtained. The procedures are designed to minimize the likelihood of mistakes in recording data due to anthropogenic host-transfers. My collaborators--Dr. Robert L. Rausch, Ms. Virginia Rausch, Dr. Terry L. Yates, and Dr. Sydney Anderson--and I have been collecting parasites in the field for more than 25 years. The protocols I present here have evolved considerably over that time and are based on our collective experience. Additional information on collecting techniques is presented in Anderson (1965) and Pritchard and Kruse (1982). Data are collected in the field laboratory in assembly-line fashion, with different individual researchers in the field crew assigned to different tasks. Every part of every animal that is collected is processed in some way. Because of the possibility of contracting various viral diseases from handling wild-caught mammals, I recommend that surgical gloves and lab coats be worn during all laboratory procedures