Long-Term Monitoring of Microsporidia, Cryptosporidium and Giardia Infections in Western Lowland Gorillas (Gorilla gorilla gorilla) at Different Stages of Habituation in Dzanga Sangha Protected Areas, Central African Republic Bohumil Sak 1 * . , Klara J. Petrzelkova 1,2,3,4. , Dana Kvetonova 1 , Anna Mynarova 5 , Kathryn A. Shutt 6 , Katerina Pomajbikova 4 , Barbora Kalousova 4,7 , David Modry 1,4,8 , Julio Benavides 9,10 , Angelique Todd 11 , Martin Kvac 1,12 1 Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, C ˇ eske ´ Bude ˇ jovice, Czech Republic, 2 Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Brno, Czech Republic, 3 Liberec Zoo, Liberec, Czech Republic, 4 Department of Pathology and Parasitology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic, 5 Faculty of Science, University of South Bohemia in C ˇ eske ´ Bude ˇjovice, Czech Republic, 6 Department of Anthropology, Durham University, Durham, United Kingdom, 7 Department of Botany and Zoology, Masaryk University, Brno, Czech Republic, 8 CEITEC - Central European Institute of Technology, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic, 9 Department of Ecology, Montana State University, Bozeman, Montana, United States of America, 10 CNRS-Institut des Sciences de l’Evolution de Montpellier, Universite ´ de Montpellier II, Montpellier, France, 11 WWF, Dzanga Sangha Protected Areas, Bangui, Central African Republic, 12 Faculty of Agriculture, University of South Bohemia in C ˇ eske ´ Bude ˇjovice, Czech Republic Abstract Background: Infectious diseases pose one of the greatest threats to endangered species, and a risk of gastrointestinal parasite transmission from humans to wildlife has always been considered as a major concern of tourism. Increased anthropogenic impact on primate populations may result in general changes in communities of their parasites, and also in a direct exchange of parasites between humans and primates. Aims: To evaluate the impact of close contact with humans on the occurrence of potentially zoonotic protists in great apes, we conducted a long-term monitoring of microsporidia, Cryptosporidium and Giardia infections in western lowland gorillas at different stages of the habituation process, humans, and other wildlife in Dzanga-Sangha Protected Areas in the Central African Republic. Results: We detected Encephalitozoon cuniculi genotypes I and II (7.5%), Enterocytozoon bieneusi genotype D and three novel genotypes (gorilla 1–3) (4.0%), Giardia intestinalis subgroup A II (2.0%) and Cryptosporidium bovis (0.5%) in gorillas, whereas in humans we found only G. intestinalis subgroup A II (2.1%). In other wild and domestic animals we recorded E. cuniculi genotypes I and II (2.1%), G. intestinalis assemblage E (0.5%) and C. muris TS03 (0.5%). Conclusion: Due to the non-specificity of E. cuniculi genotypes we conclude that detection of the exact source of E. cuniculi infection is problematic. As Giardia intestinalis was recorded primarily in gorilla groups with closer human contact, we suggest that human-gorilla transmission has occurred. We call attention to a potentially negative impact of habituation on selected pathogens which might occur as a result of the more frequent presence of humans in the vicinity of both gorillas under habituation and habituated gorillas, rather than as a consequence of the close contact with humans, which might be a more traditional assumption. We encourage to observe the sections concerning hygiene from the IUCN best practice guidelines for all sites where increased human-gorilla contact occurs. Citation: Sak B, Petrzelkova KJ, Kvetonova D, Mynarova A, Shutt KA, et al. (2013) Long-Term Monitoring of Microsporidia, Cryptosporidium and Giardia Infections in Western Lowland Gorillas (Gorilla gorilla gorilla) at Different Stages of Habituation in Dzanga Sangha Protected Areas, Central African Republic. PLoS ONE 8(8): e71840. doi:10.1371/journal.pone.0071840 Editor: Dan Zilberstein, Technion-Israel Institute of Technology Haifa 32000 Israel., Israel Received April 26, 2013; Accepted July 3, 2013; Published August 7, 2013 Copyright: ß 2013 Sak et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This study was supported by the grant of Grant Agency of the Czech Republic (number 206/09/0927). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: casio@paru.cas.cz . These authors contributed equally to this work. PLOS ONE | www.plosone.org 1 August 2013 | Volume 8 | Issue 8 | e71840