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Summary

The Nilgiri langur (Semnopithecus johnii) and common langur (Semnopithecus priam thersites) are colobines found in the southern tip of the Western Ghats. Changes in land use patterns and the loss of habitat owing to the ever-increasing demand for land to meet anthropogenic requirements are major causes for these and other primates being critically threatened today. Data regarding patterns of parasitic infections in langur populations in the wild are a critical indicator of the population health and will mark a beginning towards assessment and management of disease risks. This is especially important for populations that are in proximity to human settlements as this can either have a direct effect through contagion from humans and indirectly because of increased stress.

Objectives
  1. Fill in the paucity of information on gastrointestinal parasites of langurs in the wild.
  2. Understand the influence of human settlements within Protected Areas on the parasitic loads of these primates.
Status
  • Fresh faecal samples were collected in areas where there were human settlements and from areas where they were undisturbed. Samples were collected in the Mudanthurai plateau, Kalakkad-Mundanthurai Tiger Reserve during October 2009 and May 2011. A total of 184 fecal samples were collected, of which 102 belonged to Hanuman Langur (HL) and 82 to Nilgiri Langur (NL). Our four sample sets included faecal matter from individuals of HL and NL in areas of human settlement (HL: 74; NL: 68) and in areas of no human settlement (HL: 28, NL: 14). The samples were processed and microscopically examined to identify parasites based on morphology of eggs.
  • We identified 14 parasite eggs in HL and 20 eggs in NL. Of these, three eggs from HL and six eggs from NL samples were identified up to the family level, while the remaining were identified to the generic level.
  • Our results showed that for both langurs, parasite species richness was greater in areas in close proximity to human settlements while prevalence remained the same in the presence and absence of human settlements. Incidence-based Jaccard’s similarity index showed that parasite taxa assemblage for Hanuman langur (HL) and Nilgiri langur (NL) between the two areas was very similar.
  • For the HL, Ascaris sp. was the most dominant parasite in both areas, followed by Ancylostoma sp. in areas of no human settlement and Toxocara sp. in areas of human settlement. The prevalence of these were not significantly different in the two areas. For the NL, an unidentified cestodes sp. was the most dominant in areas with human presence, which was replaced by another unidentified cestodes species (that was found in both langurs) in areas of no human settlements. Ascaris sp. was the second most dominant parasite in NL in both zones. The prevalence of these taxa were not significantly different in the two areas.
  • Three graduate student interns were trained in sample collection, processing, laboratory techniques and identification of intestinal parasite eggs.

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