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American Journal of Primatology 73:75–83 (2011) RESEARCH ARTICLE Black and Gold Howler Monkeys (Alouatta caraya) as Sentinels of Ecosystem Health: Patterns of Zoonotic Protozoa Infection Relative to Degree of Human–Primate Contact MARTIN M. KOWALEWSKI1, JOHANNA S. SALZER2, JOSEPH C. DEUTSCH3, MARIANA RAÑO1, MARK S. KUHLENSCHMIDT3, AND THOMAS R. GILLESPIE2,4 1 Estación Biológica de Usos Múltiples de Corrientes (EBCo), Museo Argentino de Ciencias Naturales-CONICET, Argentina 2 Department of Environmental Studies and Program in Population Biology, Ecology, and Evolution, Emory University, Atlanta, Georgia 3 Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana, Illinois 4 Department of Environmental and Occupational Health, Rollins School of Public Health, Emory University, Atlanta, Georgia Exponential expansion of human populations and human activities within primate habitats has resulted in high potential for pathogen exchange creating challenges for biodiversity conservation and global health. Under such conditions, resilient habitat generalists such as black and gold howler monkeys (Alouatta caraya) may act as effective sentinels to overall ecosystem health and alert us to impending epidemics in the human population. To better understand this potential, we examined noninvasively collected fecal samples from black and gold howler monkeys from remote, rural, and village populations in Northern Argentina. We examined all samples (n 5 90) for the zoonotic protozoa Cryptosporidium sp. and Giardia sp. via immunofluorescent antibody (IFA) detection. All samples were negative for Cryptosporidium sp. The prevalence of Giardia sp. was significantly higher at the rural site (67%) compared with the remote forest (57%) and village (40%) sites. A lack of Cryptosporidium sp. in all samples examined suggests that this pathogen is not a natural component of the howler parasite communities at these sites and that current land-use patterns and livestock contact are not exposing Argentine howler monkeys to this pathogen. High prevalence of Giardia sp. at all sites suggests that howler monkeys may serve as a viable reservoir for Giardia. Significantly higher prevalence of Giardia sp. at the rural site, where primate–livestock contact is highest, suggests the presence of multiple Giardia clades or increased exposure to Giardia through repeated zoonotic transmission among nonhuman primates, livestock, and/or people. These results highlight the need for future research into the epidemiology, cross-species transmission ecology, and clinical consequences of Giardia and other infectious agents not only in humans and livestock, but also in the wild animals that share their environments. Am. J. Primatol. 73:75–83, 2011. r 2010 Wiley-Liss, Inc. Key words: Cryptosporidium; disturbance ecology; Giardia; neglected pathogens; primate; Zoonoses INTRODUCTION Exponential expansion of human populations and human activities within primate habitats has resulted in high potential for multi-directional pathogen exchange creating challenges for biodiversity conservation and global health [Gillespie et al., 2008]. Associated landscape-level disturbance may exacerbate pathogen transmission by affecting the distribution and behavior of primates [Gillespie & Chapman, 2006, 2008; Gillespie et al., 2005; Nunn & Altizer, 2006], as well as vectors of infectious diseases such as yellow fever, dengue, and malaria [Altizer et al., 2006; Hay et al., 2002]. In this regard, studies of nonhuman primates with the ability to survive in moderately disturbed habitats are of great importance for understanding the dynamics of infectious disease transmission and to evaluate the capacity of r 2010 Wiley-Liss, Inc. primates to serve as sentinels, alerting us before pathogens reach semi-urban or urban areas. The forests of Northern Argentina provide an ideal locale for examining issues related to pathogen exchange between people, nonhuman primates, and Contract grant sponsor: NIH; Contract grant number: T35 2006; Contract grant sponsors: The Wenner Gren Foundation; PostPh.D. Research Grant; Contract grant number: 7622; Contract grant sponsor: Conservation Medicine Center of Chicago. Correspondence to: Thomas R. Gillespie, E510 Math and Science Center, 400 Dowman Drive, Emory University, Atlanta, Georgia 30322. E-mail: [email protected] Received 28 September 2009; revised 26 December 2009; revision accepted 26 December 2009 DOI 10.1002/ajp.20803 Published online 18 January 2010 in Wiley Online Library (wiley onlinelibrary.com). 76 / Kowalewski et al. livestock. Here, commercial agriculture (i.e., soy plantations) and forest exploitation have profoundly changed the composition of forests, eliminating the hardiest and most economically profitable forest tree species [Zunino & Kowalewski, 2008]. Clearing entire forests for agriculture and establishing exotic, fast-growing pastures are also contributing to rapid landscape change in this region. The effects of these changes on wildlife populations remain largely unknown. In Argentina, black and gold howler monkeys, Alouatta caraya, account for the highest proportion of biomass of arboreal mammals and these monkeys often cope well with moderate deforestation [Zunino et al., 2007]. The high degree of phenotypic plasticity present in this species make black and gold howler monkeys a valuable species to test and evaluate current ideas of conservation related to the dynamics of emergent and re-emergent diseases [Kowalewski & Gillespie, 2009], since more plastic species are expected to occupy and successfully exploit a wider range of ecological conditions, leading to greater resilience to habitat seasonality and habitat modification compared with other taxa [Miner et al., 2005]. Howlers are classified as colonizers [Crockett, 1998; Crockett & Eisenberg, 1987; Eisenberg et al., 1972] due to their ability to adapt and survive in modified environments [BiccaMarques, 2003; Clarke et al., 2002a]. This ability to survive in variable environments including habitats that bring them into contact with humans [Cabral et al., 2005; Estrada et al., 2006; Muñoz et al., 2006] or increase their terrestrial travel [Kowalewski et al., 1995; Pozo-Montuy & SerioSilva, 2006; Young, 1981], make howlers an excellent model to study the dynamics of infectious disease transmission among wild primates, humans, and domestic animals. Although black and gold howlers, much like other species of Alouatta, seem to be resilient to variable levels of habitat degradation in terms of population numbers [Estrada et al., 2006; Zunino et al., 2007], a finer-scale analysis reveals a different scenario. As in colobine species [Gillespie & Chapman, 2006, 2008], howler populations living in fragmented forests seem to be carrying a more diverse community of parasites [Kowalewski & Gillespie, unpublished data; Santa Cruz et al., 2000]. Oklander [2007] revealed another trend in howler populations living in fragmented forests in Northern Argentina (the same study site of this article—EBCo-, see description in methods). Oklander [2007] used molecular techniques [13 polymorphic microsatellites developed by Oklander et al., 2007] to compare levels of homozygosity in a population living in a continuous forest and a population living in a fragmented forest (same rural population studied in this article) by estimating gene flow with Fst values. In contrast to groups living in continuous forests (our IB site, see methods), groups living in fragments presented a Am. J. Primatol. recent genetic differentiation among groups and a lower genetic heterozygosity, potentially due to limitations in dispersal opportunities [Oklander, 2007]. The impacts of habitat alteration on nonhuman primate populations occur at the individual, group, and population level. Successful mediation of these threats requires repeated evaluation of genetic diversity, health, stress, behavior, and diet. A study on red colobus (Piliocolobus tephrosceles) revealed the synergistic affects of food availability, cortisol levels, and parasite infections on the abundance of this species [Chapman et al., 2006]. Case studies of various species from sites around the world will improve our understanding of the multifactorial process that anthropogenic disturbances can initiate at different levels. In this study we examine patterns of infection with the zoonotic protozoa, Giardia, and Cryptosporidium, in populations of black and gold howler monkeys living at variable levels of contact with humans: remote, rural, and village. These protozoa infect vertebrates, including wildlife, livestock, and humans [Hill, 2001; McGlade et al., 2003; Volotão et al., 2008]. The protozoa life cycle consists of fecal–oral transmission of Giardia cysts or Cryptosporidium oocysts (infective stage), typically via contaminated water and food. Within the host animal, the life cycle of the protozoa continues as the cysts or oocysts develop into trophozoites. The trophozoites infect cells within an animal host’s duodenum; often leading to severe diarrhea [Thompson, 2004]. Giardia is cosmopolitan and constitutes a recognized waterborne infection for humans and animals, responsible for well over one billion cases of human diarrheal disease annually [Crompton, 2000; Teodorovic et al., 2007; WHO/UNICEF, 2000]. Giardiasis is now considered by the World Health Organization to be a ‘‘neglected disease,’’ due to its ubiquity in equatorial latitudes, its chronic detrimental health effects (especially in children), its propensity to infect economically disadvantaged populations, and the paradoxical availability of relatively inexpensive and effective pharmaceuticals for its treatment [Savioli et al., 2006]. In Latin America almost 15% of the rural population is infected with Giardia [Atı́as, 1999]. In Argentina, two human studies showed a prevalence of 10% in urban areas, 34% in small towns (same as villages considered in our study) [Gamboa et al., 2003], and 4% in rural areas [Minvielle et al., 2004]. In animals from this region the reported prevalence of Giardia is 7.5% in cattle, 18.6% in dogs, and 3.9% in rodents [Pezzani et al., 2003]. These parasites have been reported in other nonhuman primates including mountain gorillas (Gorilla gorilla berengei) [Graczyk et al., 2002], black howler monkeys (Alouatta pigra) [Vitazkova & Wade, 2006], brown howling monkey (Alouatta guariba) [Cabral et al., 2005; Volotão et al., 2008], red colobus (Pilocolobus tephrosceles) [Salzer Howler Monkeys as Sentinels for Conservation and Health / 77 et al., 2007] and red-tailed guenons (Cercopithecus ascanius) [Salzer et al., 2007]. As evidenced from the examples above, giardiasis is often endemic in human populations; however, the frequency and pathogenicity of this agent remains largely unknown in wildlife [Appelbee et al., 2005; Levy et al., 1998]. The main symptoms of giardiasis in humans are diarrhea, abdominal pain, nausea, and vomiting [Acha & Szyfres, 2003]. The disease is generally described as an acute diarrheal illness that may last up to six weeks although chronic patients are also found, especially in cases of impaired immunocompetence [Chester et al., 1985]. METHODS Study Sites This study was conducted in four sites that differ in their degree of human use: Isla Brasilera (IB) (271200 S, 581400 W), Estación Biológica Corrientes-Biological Field Station Corrientes- (EBCO) (271300 S, 581410 W), Cerrito (C) (271170 S, 581370 W), and San Cayetano (SC) (271340 S, 581420 W) (Fig. 1). IB is an island characterized by a continuous flooded forest where howler groups exhibit extensive home range overlap, but little to no human contact. The island has an area of 290 ha and we have identified between 32–35 groups. IB is 20 km north of EBCO (Fig. 1), a rural site characterized by semi-deciduous forest surrounded by a matrix of grassland. At EBCO, in general there is one group of howlers per forest fragment. We have identified 34 groups of howlers in 24 forest fragments (area from 3 ha to approximately 30 ha) covering a total area of 3,000 ha [see Zunino et al., 2007 for details]. This site is under continuous deforestation due to selective logging and clearing of fragments for cattle ranches and howlers have the potential of close contact with cattle, other domestic animals, and humans when accessing shared water sources and during terrestrial travel. Terrestrial travel is typical of other howler populations living in similar conditions [Clarke et al., 2002b; Glander, 1992; Horwich & Lyon, 1998; Pozo-Montuy & Serio-Silva, 2006]. Human houses are distributed uniformly across this rural site. We also sampled howlers from two village sites, Cerrito town (C) near IB (there are two groups of howlers living in this town of 1,500 human inhabitants) and SC next to the EBCO with almost 4,000 human inhabitants (there are 7–8 groups living in close proximity with family houses whose tree crowns are contiguous with trees in the forest fragments). In summary, the four areas were classified into three habitat types: remote (IB), rural (EBCO), and village (C and SC). The climate of all sites is subtropical with an average annual temperature of 21.61C and an annual average of rainfall of 1,200 mm [Rumiz et al., 1986]. Rains increase slightly towards the spring–summer (September to December). Study Population We collected 90 fecal samples from different individuals during March 2008 (fall season): 30 samples from the village sites (C and SC), 30 samples from the rural site (EBCO) and 30 samples from the Fig. 1. Location of study areas of black and gold howler monkeys (Alouatta caraya) in northern Argentina: San Cayetano (SC) and Cerrito (C) were considered village sites, Isla Brasilera (IB) a remote site, and EBCO a rural site. Am. J. Primatol. 78 / Kowalewski et al. remote site (IB). Each sample set consisted of 30 samples and included 10 adult males, 10 adult females, 4 adult females with lactating infants, and approximately 3 juvenile males and 3 juvenile females (the number of juveniles varied across groups). These samples were collected from different groups of howlers in each site. Sample Analysis Fecal samples were collected immediately after defecation in (March 2008) and preserved in 10% neutral buffered formalin [Gillespie, 2006]. When collected, fecal consistency was characterized as liquid, soft, medium, or solid. We used a Merifluor Cryptosporidium/Giardia Direct Immunofluorescent Detection Kit (Meridian Bioscience Inc, Cincinnati, Ohio) to detect both parasites of interest—Crystoporidium oocysts and Giardia cysts based on monoclonal antibodies [Johnston et al., 2003]. The analysis was run in July 2008. Fecal samples were scored both for the presence or absence of the pathogens as well as quantification of Cryptosporidium oocysts and Giardia cysts in feces. Fecal samples were concentrated and then resuspended in 1 g/1 mL suspensions. Counts were calculated by analyzing 10 mL of the 1 g/mL solution of concentrated feces from each sample. Oocysts or cysts were then quantified by counting total numbers in 150 microscope fields (400 magnification) and extrapolating results to the entire sample. This method was validated by spiking negative fecal samples with known numbers of Cryptosporidium sp. oocysts. Statistical Analyses Differences in the frequency and prevalence of infections across sites and differences in frequencies of fecal consistency were compared using w2 tests. We used Kruskall Wallis ANOVA to explore differences of intensity of infection across sites. We considered a criterion for significance for all statistical tests at Po0.05. This research complied with the American Journal of Primatology and University of Illinois guidelines for the ethical treatment of primates (IACUC protocol 06207) and the laws of Argentina. RESULTS All samples were negative for Cryptosporidium sp. Seventeen of 30 samples (57%) in the remote site, 20 of 30 samples (67%) in the rural area, and 12 of 30 samples (40%) in the village areas were positive for Giardia sp. When the remote, rural, and village sites were compared collectively, the prevalence of Giardia sp. infection in black and gold howler monkeys was not significantly related to the location of sampling (w2 test, df 5 2, P>0.05). When sampling locations were compared individually (remote vs. village, rural vs. village, and remote vs. rural), significant Am. J. Primatol. Fig. 2. Giardia sp. cysts/gram in black and gold howler monkey (Alouatta caraya) feces from remote, rural, and urban sites in northern Argentina. differences were found between rural and village areas (w2 test, df 5 1, Po0.03). No fecal samples were scored as liquid. From a total of 49 positive samples, 15 (31%) were characterized as soft, 27 (55%) as medium and 7 (14%) as solid. These results suggest that the consistency of fecal material is independent of the infected state of the individuals (w2 test, df 5 2, Po0.05). We also compared cysts per gram of fecal material, providing an index of intensity of shedding and environmental contamination with Giardia. Although the mean value of cysts per gram was highest in remote areas (250.9, range 5 4–1,064), followed by village areas (194.7, range 5 1–790) and rural areas (113.5, range 5 1–845); there were no significant differences in the relative number of cysts per sample across areas (Kruskall Wallis ANOVA, H ¼2ðN¼49Þ ¼3, P40.05) (Fig. 2). DISCUSSION Our results demonstrate that Giardia sp. is present and prevalent in wild black and gold howlers at all points along a gradient of anthropogenic disturbance. In these same populations, there is no evidence of infection with Cryptosporidium sp. A lack of Cryptosporidium sp. in all samples examined suggests this pathogen is not a natural component of the howler parasite communities at these sites and that current land-use patterns are not exposing Argentine howler monkeys to this pathogen. Cryptosporidium oocysts were found in people in urban and semi-urban populations close to our study sites [Ledesma et al., 2006], but it was never reported for the rural area considered in this article [Borda et al., 1996]. High prevalence of Giardia sp. at all sites regardless of human–primate contact rates suggest that howler monkeys may serve as a viable reservoir Howler Monkeys as Sentinels for Conservation and Health / 79 for Giardia sp. Considered among the most common human intestinal protozoa, Giardia ranges in clinical presentation from asymptomatic to highly pathogenic, causing chronic malabsorptive diarrhea in some patients [Thompson, 2004]. Both host factors (e.g., nutrition, immunity, co-infection with other agents) and pathogen factors (e.g., strain, infectious dose) are thought to contribute to the severity of clinical disease [Thompson, 2000]. In our study, we did not characterize any howler monkey fecal samples as liquid, however; we did find that infected animals had more fecal samples scored as soft and/or medium than noninfected animals. The lack of a strong measurable association between infection and an acute gastrointestinal symptom (i.e., diarrhea) in our study population was surprising, but it is concordant with recent studies of humans. Although Giardia is associated with clinical disease in developed economies, evidence is nevertheless mounting that it may be commensal in rural settings where people may normally be exposed to diverse parasite communities from an early age. For example, Cordón et al. [2008] found Giardia at 28.1% prevalence in diarrheic Peruvian children, as well as in 19.5% of nondiarrheic children, emphasizing the importance of asymptomatic patients in Giardia transmission where hygiene and sanitation are poor [Cordón et al., 2008]. Other studies in India [Traub et al., 2003], Ethiopia [Ayalew et al., 2008], Bangladesh [Dib et al., 2008], and Peru [Hollm-Delgado et al., 2008] have found similarly weak or nonexistent associations between G. duodenalis infection status and gastrointestinal symptoms, suggesting that G. duodenalis may coexist benignly with human hosts under conditions where acquired immunity to the pathogen can develop. Lack of early exposure and acquired immunity to G. duodenalis may, in fact, account for the role of the pathogen as a cause of sporadic diarrheal outbreaks in developed countries [Istre et al., 1984], as well as a major cause of traveler’s diarrhea for people from developed countries who visit endemic areas [Reinthaler et al., 1998; Shlim et al., 1999]. The interplay between clinical symptoms and Giardia infections in wildlife are far less known. We hope to explore the association between symptom and infection in black and gold howler monkeys and other wildlife species in more detail in future work. Giardia is also notable for zoonotic transmission [Thompson, 2004]. The protozoan’s propensity to cross species barriers results from the host nonspecificity of the trophozoite as well as from the high infectivity and environmental stability of the Giardia cyst [Smith & Nichols, 2006]. The fact that Giardia sp. prevalence was significantly higher at the rural site in our study, where monkeys have the highest contact rates with cattle and other domestic animals, suggests that repeated zoonotic transmission may amplify baseline rates of infection [Zunino & Kowalewski, 2008]. There are several reasons to expect higher rates of contact between howlers and cattle, a common source of protozoal zoonotics, in this rural site. First, cattle routinely enter forest fragments inhabited by howlers looking for shade and young pastures, opening trails and defecating along them. Second, howlers drink water from creeks where cattle drink and defecate [Kowalewski & Raño, personal observation]. Finally, increased levels of deforestation decrease the size of these fragments and obligate howlers to descend to cross from fragment to fragment looking for food resources [Zunino et al., 2007] increasing the likelihood of contact with parasites on the ground and in small water bodies. As in the case of the rural site, we also found high prevalence of Giardia in howler populations in the two other sites (remote and village). Giardia had a prevalence of 57% in the remote site. Although this site lacks permanent human settlements, there are occasional visitors from neighboring towns that bring a limited number (10–20) of cattle onto the island, which drink from the same lagoons that the monkeys use as a water source [Bravo & Sallenave, 2003; Kowalewski, 2007]. Giardia duodenalis was reported in brown howling monkeys (Alouatta guariba), as the result of contact of these monkeys with other wildlife, such as opossums, which live in a nearby forest fragment and circulate near human dwellings [Muller et al., 2000; Volotão et al., 2007] or contact with humans such as fishermen, poachers, or researchers [Volotão et al., 2007; see also Vitazkova & Wade, 2007]. Similarly, intensified gorilla–human interaction has been suggested to enhance transmission of anthropogenic pathogens including Giardia [see Graczyk et al., 2001a,b, 2002; Nizeyi et al., 1999]. Although the village site in our study revealed the lowest prevalence of Giardia (40%), this value is high relative to Giardia prevalence in other wild primate populations examined. A study in 1983 of children from the public school at this site (SC) showed a 29% (n 5 60) prevalence of Giardia lambia (5 Giardia duodenalis) infection [Borda et al., 1996]. The interactive affects of poverty, low levels of education, unsanitary conditions, and increased levels of deforestation experienced at this site may result in increased contact between wildlife and humans, producing unexpected results in the transmission patterns of infectious diseases. Vitazkova and Wade [2007] suggested a positive relationship between primate density and prevalence of Giardia sp. in a population of Alouatta pigra during the dry season in Belize and Mexico. In our study, we find the opposite trend with highest prevalence at the site with the lowest primate density (1.04 howlers/ha for the rural site) and lowest prevalence at the site with the highest primate density (3.25 howlers/ha for the remote site) [Kowalewski & Zunino, 2004; Zunino et al., 2007]. Am. J. Primatol. 80 / Kowalewski et al. This pattern suggests that other factors associated with anthropogenic disturbance such as physical characteristics of sites (humidity, water availability), history of both parasites and hosts in sites, variation in the use of space, and stress may trump host density in driving patterns of infection with directly transmitted pathogens. Black and gold howlers living in fragmented areas have shown a higher diversity of gastrointestinal parasites [Kowalewski & Gillespie, unpublished data] potentially due to an increase in contact with cattle, domestic animals, and humans. In addition, a study carried out at the same rural site has shown that howlers have higher levels of homozygosity than in areas remote from human occupations with continuous forests [Oklander, 2007; Oklander et al., 2007]. Collectively, this suggests that howlers are viable sentinels for overall ecosystem health. For example, in 2007, an outbreak of yellow fever decimated the population of A. caraya and A. guariba in the Province of Misiones (Argentina) located north of the field sites of the current study [Agostini et al., 2008; Holzmann, personal communication]. This outbreak also affected humans in the area. In 2008, one year after these reports were made, we found dead howlers (A. caraya) in the same province (Corrientes) that likely succumbed to yellow fever near our study site. Unfortunately, supplies were not available to allow for diagnostic confirmation. The yellow fever wave is progressing to the South of Argentina. Howler deaths constitute an important signal of an impending public health threat that can alert officials of the need to intervene to block conversion of a sylvatic (i.e., forest cycle) into an urban cycle of this deadly human disease. Black and gold howlers are effective sentinels of yellow fever, and ongoing study of their populations may help us to prevent and better understand the yellow fever transmission dynamics. Beyond the case of yellow fever, resilient habitat generalists such as the black and gold howlers can act as effective sentinels of overall ecosystem health and alert us to impending epidemics in human populations. Consequently, we view the results of this study as indicating a strong need for future research into the epidemiology, crossspecies transmission ecology, and clinical consequences of Giardia and other infectious agents not only in humans and livestock, but also in the wild animals that share their environments. Recommendations Successful outcomes involving emerging and remerging infectious diseases require a proactive approach, ideally avoiding introduction of infectious agents into human, livestock, and threatened wildlife populations altogether. Consequently, surveillance efforts need to be strongest in areas of increasing contact between humans and wildlife and Am. J. Primatol. in poverty-stricken communities where health systems are inadequate. Our study is an illustration of how these exploratory evaluations may benefit these efforts. Establishment of long-term study sites allow researchers to catalog rare events and build knowledge and collaborations over time to better understand the dynamics of infectious diseases and to potentially prevent future outbreaks. For example, data presented in this article are part of a long-term and ongoing study of ecosystem health in northern Argentina, which includes an evaluation of several pathogens in humans, domesticated animals and nonhuman primates among other wild mammals. In addition to incorporating government institutions and public universities, our data collection and sampling design allows the comparison of our results with similar projects carried out using standardized methods around the globe [Gillespie, 2006; Gillespie et al., 2008]. Impoverished people with limited access to basic hygienic services or adequate health systems are often most susceptible to emerging diseases. These same people and wildlife that live in surrounding habitats are often the most affected by the negative consequences of large-scale habitat modifications, despite being rarely responsible for such habitat modification [Alarcón-Cháires, 2006]. Local and national governments must invest resources in development for such communities in terms of education, health, and conservation programs and hold large local landowners and international corporations that produce the highest impact on wildlife through the establishment of pastures and largescale plantations of soy, oil palm, rice, and other global agricultural commodities accountable for their impacts on human, animal, and ecosystem health [De la Cruz, 2004; Martı́nez Alier, 2005]. Researchers can play an important role in conservation and development that extends far beyond the dissemination of results through international scientific journals. They can expand their capacity by assembling multidisciplinary teams for conservation and health applications, establishing education programs that incorporate local people and researchers in areas of study, and conveying information to local communities through radio, newspaper, and community meetings. Most importantly, researchers can help colleagues and students in developing countries to obtain training and funding for ongoing and proposed research. Our current knowledge regarding wild primate pathogens remains minimal and skewed toward regions of long-term primate research. Fortunately, integration of standardized empirical data collection, state-of-the-art diagnostics, and the comparative approach offers the opportunity to create a baseline for patterns of infection in wild primate populations; to better understand the role of disease in primate ecology, behavior, and evolution; and to examine how anthropogenic effects alter the zoonotic potential of Howler Monkeys as Sentinels for Conservation and Health / 81 various pathogenic organisms. Considering the evolutionary and ecological links between primates and their pathogens, observing changes in patterns of infection by naturally occurring pathogens in sentinels like black and gold howlers has the capacity to alert us to potentially imminent threats to primate conservation and human health. ACKNOWLEDGMENTS The study complies with the current laws of the countries in which it was conducted (IACUC protocol 06207). We thank our field assistants and collaborators who helped collect samples: Silvana Peker, Romina Pave, Amparo Perez-Rueda, Ramon Martinez, and Miguel Blanco. Silvana Peker also provided a vehicle (R12) to visit different field sites. REFERENCES Acha PN, Szyfres B. 2003. Zoonoses and communicable diseases common to man and animal, 3rd ed., Vol. III. Parasitoses. Pan American Health Organization, WHO. Agostini I, Holzmann I, Di Bitetti MS. 2008. Infant hybrids in a newly formed mixed species group of howler monkeys (Alouatta guariba clamitans and Alouatta caraya) in northeastern Argentina. Primates 49:304–307. Alarcón-Cháires P. 2006. Riqueza ecológica versus pobreza social. Contradicciones y perspectivas del desarrollo indı́gena en Latinoamérica. In: Cimadamore AD, Eversole R, McNeish JA, editors. Pueblos indı́genas y pobreza. Enfoques multidisciplinarios. CLACSO, Consejo Latinoamericano de Ciencias Sociales, Buenos Aires. Altizer S, Dobson A, Hosseini P, Hudson P, Pascual M, Rohani P. 2006. Seasonality and the dynamics of infectious diseases. Ecology Letters 9:467–484. Appelbee AJ, Thompson RCA, Olson ME. 2005. Giardia and Cryptosporidium in mammalian wildlife–current status and future needs. Trends in Parasitology 21:370–376. Atı́as A. 1999. El hospedero. La relación hospedero-parasito (The host. Host–parasite relationship). In: Atias A, editor. Parasitologı́a médica. Mediterraneo: Chile. p 49–53. Ayalew D, Boelee E, Endeshaw T, Petros B. 2008. Cryptosporidium and Giardia infection and drinking water sources among children in Lege Dini, Ethiopia. Tropical Medicine & International Health 13:472–475. Bicca-Marques JC. 2003. How do howler monkeys cope with habitat fragmentation? In: Marsh LK, editor. Primates in fragments: ecology and conservation. New York: Kluwer Academic/Plenum Publishers. p 283–303. Borda CE, Rea MJ, Rosa JR, Maidana C. 1996. Intestinal parasitism in San Cayetano, Corrientes, Argentina. Bulletin of the Pan American Health Organization 30:227–233. Bravo SP, Sallenave A. 2003. Foraging behavior and activity patterns of Alouatta caraya in the northeastern Argentinean flooded forest. International Journal of Primatology 24:825–846. Cabral JNH, Rossato RS, de M Gomes MJT, Araújo FAP, Oliveira F, Praetzel K. 2005. Gastrointestinais de bugiosruivos (Alouatta guariba clamitans Cabrera 1940) da região extremo-sul de Porto Alegre/RS, Brasil, diagnosticados através da coproscopia: implicac- ões para a conservac- ão da espécie e seus ha. Congresso Brasileiro de Parasitologia, Porto Alegre, RS, Brasil [Abstract]. Chapman CA, Wasserman MD, Gillespie TR, Speirs ML, Lawes MJ, Saj TL, Ziegler TE. 2006. Do nutrition, parasitism, and stress have synergistic effects on red colobus populations living in forest fragments? American Journal of Physical Anthropology 131:525–534. Chester AC, MacMurray FG, Restifo MD, Mann O. 1985. Giardiasis as a chronic disease. Digestive Diseases and Sciences 30:215–218. Clarke MR, Crockett CM, Zucker EL, Zaldivar M. 2002a. Mantled howler population of Hacienda La Pacifica, Costa Rica, between 1991 and 1998: effects of deforestation. American Journal of Primatology 56:155–163. Clarke MR, Collins DA, Zucker EL. 2002b. Responses to deforestation in a group of mantled howlers (Alouatta palliata) in Costa Rica. International Journal of Primatology 23:365–381. Cordon PG, Soldan OCP, Vasquez VF, Soto VJR, Bordes SL, Moreno SM, Rosales MJ. 2008. Prevalence of enteroparasites and genotyping of Giardia lamblia in Peruvian children. Parasitology Research 103:459–465. Crockett CM. 1998. Conservation biology of the genus Alouatta. International Journal of Primatology 19:549–578. Crockett CM, Eisenberg JF. 1987. Howlers: variations in group size and demography. In: Smuts BB, Cheney DL, Seyfarth RM, Wrangham RW, Struhsaker TT, editors. Primate Societies. Chicago: The University of Chicago Press. p 54–68. Crompton DW. 2000. The public health importance of hookworm disease. Parasitology 121:39–50. De la Cruz R. 2004. Visión de los Pueblos Indı́genas en el contexto de las decisiones sobre ABS y 8 (j): Impacto de las decisiones de la CDB/COP sobre el mandato de la IGC de la OMPI. Notas Informales. Policy and Global Change Series. Trade and Biodiversity. COICA, ICTSD and IUCN. Dib HH, Lu SQ, Wen SF. 2008. Prevalence of Giardia lamblia with or without diarrhea in South East, South East Asia and the Far East. Parasitology Research 103:239–251. Eisenberg JF, Muckenhirn NA, Rudran R. 1972. The relation between ecology and social structure in primates. Science 176:863–874. Estrada A, Saenz J, Harvey C, Naranjo E, Muñoz D, RosalesMeda M. 2006. Primates in agroecosystems: conservation value of some agricultural practices in Mesoamerican landscapes. In: Estrada A, Garber PA, Pavelka MSM, Luecke L, editors. New perspectives in the study of Mesoamerican Primates: distribution, ecology, behavior, and conservation. New York: Springer. p 437–470. Gamboa M, Basualdo J, Córdoba M, Pezzani B, Minvielle M, Lahitte H. 2003. Distribution of intestinal parasitoses in relation to environmental and sociocultural parameters in La Plata, Argentina. Journal of Helminthology 77:15–20. Gillespie TR. 2006. Noninvasive assessment of gastrointestinal parasite infections in free-ranging primates. International Journal of Primatology 27:1129–1143. Gillespie TR, Chapman CA. 2006. Forest fragment attributes predict parasite infection dynamics in primate metapopulations. Conservation Biology 20:441–448. Gillespie TR, Chapman CA. 2008. Forest fragmentation, the decline of an endangered primate, and changes in host–parasite interactions relative to an unfragmented forest. American Journal of Primatology 70:222–230. Gillespie TR, Chapman CA, Greiner EC. 2005. Effects of logging on gastrointestinal parasite infections and infection risk in African primates. The Journal of Applied Ecology 42:699–707. Gillespie TR, Nunn CL, Leendertz FH. 2008. Integrative approaches to the study of primate infectious disease: implications for biodiversity conservation and global health. Yearbook of Physical Anthropology 51:53–69. Glander KE. 1992. Dispersal patterns in Costa Rica mantled howling monkeys. American Journal of Primatology 13:415–436. Graczyk TK, Marcogliese DJ, deLafontaine Y, DaSilva AJ, Mhangami-Ruwende, Pieniazek NJ. 2001a. Cryptosporidium parvum oocysts in zebra mussels (Dreissena polymorpha): evidence from the St. Lawrence River. Parasitology Research 87:231–234. Am. J. Primatol. 82 / Kowalewski et al. Graczyk TK, DaSilva AJ, Cranfield MR, Bosco Nizeyi J, Kalema GRNN, Pieniazek NJ. 2001b. Cryptosporidium parvum Genotype 2 infections in free-ranging mountain gorillas (Gorilla gorilla beringei) of the Bwindi Impenetrable National Park, Uganda. Parasitology Research 87: 368–370. Graczyk TK, Bosco-Nizeyi J, Ssebide B, Thompson RC, Read C, Cranfield MR. 2002. Anthropozoonotic Giardia duodenalis genotype (assemblage) a infections in habitats of freeranging human-habituated gorillas, Uganda. Journal of Parasitology 88:905–909. Hay SI, Cox J, Rogers DJ, Randolph SE, Stern DI, Shanks DG. 2002. Climate change and the resurgence of malaria in the East African highlands. Nature 415:905–909. Hill DR. 2001. Giardia lamblia. In: Gillepie S, Pearson RD, editors. Principles and practice of clinical parasitology. John Wiley & Sons. p 219–241. Hollm-Delgado MG, Gilman RH, Bern C, Cabrera L, Sterling CR, Black RE, Checkley W. 2008. Lack of an adverse effect of Giardia intestinalis infection on the health of Peruvian children. American Journal of Epidemiology 168:647–655. Horwich RH, Lyon J. 1998. A Belizean rain forest—the community Baboon Sanctuary, 3rd ed. Orangutan, Gays Mills. Istre GR, Dunlop TS, Gaspard GB, Hopkins RS. 1984. Waterborne giardiasis at a mountain resort: evidence for acquired immunity. American Journal of Public Health 74:602–604. Johnston SP, Ballard MM, Beach MJ, Causer L, Wilkins PP. 2003. Evaluation of three commercial assays for detection of Giardia and Cryptosporidium organisms in fecal specimens. Journal of Clinical Microbiology 41:623–626. Kowalewski MM. 2007. Patterns of affiliation and co-operation in howler monkeys: an alternative model to explain social organization in non-human primates. Dissertation. Department of Anthropology, University of Illinois. UrbanaChampaign. 362p. AAT 3290280. Kowalewski MM, Gillespie TR. 2009. Ecological and anthropogenic influences on patterns of parasitism in free-ranging primates: a meta-analysis of the Genus Alouatta. In: Estrada A, Garber P, Strier K, Bicca-Marques J, Heymann E, editors. South American Primates: testing new theories in the study of primate behavior, ecology, and conservation. New York: Springer. p 433–461. Kowalewski MM, Zunino GE. 2004. Birth seasonality in Alouatta caraya in Northern Argentina. International Journal of Primatology 25:383–400. Kowalewski MM, Bravo SP, Zunino GE. 1995. Aggressions between males of Alouatta caraya in forest patches from northern Argentina. Neotropical Primates 3:179–181. Ledesma A, Gorodner JO, Fernández GJ. 2006. Cryptosporidium sp. en infantes de barrios periféricos de Resistencia, Chaco. Comunicaciones Cientı́ficas y Tecnológicas/Universidad Nacional del Nordeste, CHACO: Argentina. Levy D, Bens M, Craun G, Calderon R, Herwaldt B. 1998. Surveillance for Waterborne-Disease Outbreaks—United States, 1995–1996. Morbidity and Mortality Weekly Report CDC Surveillance Summaries 47:1–34. Martı́nez Alier J. 2005. El ecologismo de los pobres. Barcelona: Icaria Editorial. McGlade TR, Robertson ID, Elliot AD, Thompson RCA. 2003. High prevalence of Giardia detected in cats by PCR. Veterinary Parasitology 110:197–205. Miner BG, Sultan SE, Morgan SG, Padilla DK, Relyea RA. 2005. Ecological consequences of phenotypic plasticity. Trends in Ecology & Evolution 20:685–692. Minvielle M, Pezzani B, Cordoba M, De Luca M, Apezteguı́a M, Basualdo J. 2004. Epidemiological survey of Giardia spp and Blastocystis hominis in an Argentinian rural community. Korean Journal of Parasitology 42:61–66. Muñoz D, Estrada A, Naranjo E, Ochoa S. 2006 Foraging ecology of howler monkeys in a cacao (Theobroma cacao) Am. J. Primatol. plantation in Comalcalco, Mexico. American Journal of Primatology 68:127–142. Muller GCK, Krambeck A, Hirano ZNB, Silva Filho HH. 2000. Levantamento preliminar de endoparasitas em bugı́os Alouatta clamitans. Neotropical Primates 8:107–108. Nizeyi JB, Mwebe R, Nanteza A, Cranfield MR, Kalema GR, Graczyk TK. 1999. Cryptosporidium sp. and Giardia sp. infections in mountain gorillas (Gorilla gorilla berengei) of the Bwindi Impenetrable National Park, Uganda. The Journal of Parasitology 85:1084–1088. Nunn CL, Altizer S. 2006. Infectious diseases in primates: behavior, ecology and evolution. New York: Oxford Series in Ecology and Evolution, Oxford University Press. Oklander LI. 2007. Estructura social y relaciones de parentesco en poblaciones silvestres de monos aulladores (Alouatta caraya) del noreste argentino. Dissertation, Universidad de Buenos Aires, Argentina. Oklander LI, Zunino GE, Di Fiore A, Corach D. 2007. Isolation, characterization and evaluation of 11 autosomal STRs suitable for population studies in black and gold howler monkeys Alouatta caraya. Molecular Ecology Notes 7:117–120. Pezzani B, Minvielle M, Laplace R, Cotter G, Basualdo J. 2003. Presencia de elementos parasitarios en contenido intestinal de múridos de la ciudad de La Plata. Acta Bioquı́mica Clı́nica Latinoamericana 1:87. Pozo-Montuy G, Serio-Silva JC. 2006. Movement and resource use by a group of Alouatta pigra in a forest fragment in Balancán, México. Primates 48:102–107. Reinthaler FF, Feierl G, Stunzner D, Marth E. 1998. Diarrhea in returning Austrian tourists: epidemiology, etiology, and cost-analyses. Journal of Travel Medicine 5:65–72. Rumiz DI, Zunino GE, Obregozo ML, Ruiz JC. 1986. Alouatta caraya: habitat and resource utilization in Northern Argentina. In: Taub DM, King FA, editors. Current Perspectives in Primate Social Dynamics. New York: Van Nostrand Rehinol. p 175–193. Salzer JS, Rwego IB, Goldberg TL, Kuhlenschmidt MS, Gillespie TR. 2007. Giardia sp. and Cryptosporidium sp. infections in primates in fragmented and undisturbed forest in western Uganda. Journal of Parasitology 93:439–440. Santa Cruz ACM, Borda JT, Patiño EM, Gomez L, Zunino GE. 2000. Habitat fragmentation and parasitism in howler monkeys (Alouatta caraya). Neotropical Primates 8: 146–148. Savioli L, Smith H, Thompson A. 2006. Giardia and Cryptosporidium join the ‘‘Neglected Diseases Initiative.’’ Trends in Parasitology 22:203–208. Shlim DR, Hoge CW, Rajah R, Scott RM, Pandy P, Echeverria P. 1999. Persistent high risk of diarrhea among foreigners in Nepal during the first 2 years of residence. Clinical Infectious Diseases 29:613–616. Smith H, Nichols RA. 2006. Zoonotic protozoa—food for thought. Parasitologia 48:101–104. Teodorovic S, Braverman JM, Elmendorf HG. 2007. Unusually low levels of genetic variation among Giardia lamblia isolates. Eukaryotic Cell 6:1421–1430. Thompson RC. 2000. Giardiasis as a re-emerging infectious disease and its zoonotic potential. International Journal of Parasitology 30:1259–1267. Thompson RCA. 2004. Epidemiology and zoonotic potential of Giardia infections. In: Sterling CR, Adam RD, editors. World class parasites, Vol. 8: the pathogenic enteric protozoa: Giardia, Entamoeba, Cryptosporidium and Cyclospora. Boston, Massachusetts: Kluwer Academic Publishers. p 1–14. Traub RJ, Robertson ID, Irwin P, Mencke N, Monis P, Thompson RC. 2003. Humans, dogs and parasitic zoonosesunravelling the relationships in a remote endemic community in northeast India using molecular tools. Parasitology Research 90:156–157. Howler Monkeys as Sentinels for Conservation and Health / 83 Vitazkova SK, Wade SE. 2006. Parasites of free-ranging black howler monkeys (Alouatta pigra) from Belize and Mexico. American Journal of Primatology 68:1089–1097. Vitazkova SK, Wade SE. 2007 Effects of Ecology on the Gastrointestinal Parasites of Alouatta pigra. International Journal of Primatology 28:1327–1343. Volotão ACC, Costa-Macedo LM, Haddad FS, Brandão A, Peralta JM, Fernandes O. 2007. Genotyping of Giardia duodenalis from human and animal samples from Brazil using beta-giardin gene: a phylogenetic analysis. Acta Tropica 102: 10–19. Volotão ACC, Souza Júnior JC, Grassinia C, Peralta JM, Fernandes O. 2008. Genotyping of Giardia duodenalis from Southern Brown Howler Monkeys (Alouatta clamitans) from Brazil. Veterinary Parasitology 158:133–137. WHO/UNICEF. 2000. Global water supply and sanitation assessment 2000 report. WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation. WHO, Geneva, Switzerland. Young OP. 1981. Chasing behavior between males within a howler monkey troop. Primates 22:424–426. Zunino GE, Kowalewski MM. 2008. Primate research and conservation in northern Argentina: the field station Corrientes (Estación Biológica de Usos Múltiples–EBCo). Tropical Conservation Science 1:140–150. Zunino GE, Kowalewski MM, Oklander LI, Gonzalez V. 2007. Habitat fragmentation and population trends of the black and gold howler monkey (Alouatta caraya) in a semideciduous forest in northern Argentina. American Journal of Primatology 69:966–975. Am. J. Primatol.