Searching Before It Is Too Late: A Survey of Blood Parasites in Ctenosaura melanosterna, a Critically Endangered Reptile of Honduras

For species at risk of extinction, any parasites they have would be expected to face a similar fate. In such cases, time is running out for efforts to identify and study their parasitic fauna before they are gone. We surveyed the hemoparasite fauna of 50 black-chested, spiny-tailed iguanas (Ctenosaura melanosterna), a critically-endangered species, on an island off the coast of Honduras. Blood samples from captured animals were tested for hemoparasites by thin blood smear and molecular analyses. Based on microscopy, two parasites were identified, a Plasmodium sp. in 14% of iguanas and a Hepatozoon sp. in 32%. For both parasites, parasitemia levels were <0.1%. Prevalence and parasitemias of Hepatozoon declined with increasing host size, a pattern differing from most prior studies of saurian reptiles. From a subset of iguanas with microscopy-confirmed Plasmodium infections, sequence analysis of 454？bp of the cytochrome b gene indicated that the Plasmodium species was distinct from known Plasmodium and was most closely related to P. chiricahuae (96.5% similarity) followed by P. mexicanum (95.8% similarity). Efforts to amplify the Hepatozoon parasite using PCR were not successful. Additional surveys and studies of this host-parasite system would be valuable, both to science and to the management of this endangered animal. 1. Introduction When an entire species is in danger of becoming extinct, those species that depend on the endangered species, such as its parasite fauna, are also doomed to extinction unless the host species can be protected. In many cases, especially with endangered species that have been little studied, their associated parasites are being lost even before they can be observed, classified, and formally described [1]. In addition, hosts that are threatened often have limited ranges and/or small populations, which can further reduce their parasite fauna [2]. For many years the task of identifying the parasites associated with organisms of conservation concern was not a priority, or if it was, it was only because they were considered threats to conservation goals [3]. In more recent years, there has been a shift in thinking about the integral role of parasites in ecosystems, along with a new effort to impress upon conservationists, veterinarians, and laypersons that the preservation of biodiversity, one of the fundamental objectives of conservation, should include parasites [3–5]. At the very least, all efforts should be made to identify parasites in any hosts that are on a path to extinction, lest they disappear before being documented by