Data from: Helminth infection in wild golden monkeys (Cercopithecus mitis kandti) in Rwanda
Data files
Jul 11, 2026 version files 104.28 KB
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Golden_monkey_parasite_data_for_Dryad_updated.xlsx
99.63 KB
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README.md
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Abstract
Habitat loss is one of the greatest threats to extant primates with effects that are immediate and time delayed. Identifying how habitat loss affects wildlife, particularly vulnerable populations, is important to understand the mechanisms that can lead to population decline. We built on previous studies of the effects of habitat loss in primates by assessing how recent, rapid, and large-scale habitat loss has affected helminth infection in two populations of golden monkeys in Rwanda. Specifically, we examined how location (Volcanoes National Park vs Gishwati Forest, Rwanda) and human contact (low vs. high) affected parasite infection using records of helminths identified morphologically from feces. We explored the effect of population or human contact (assigned via participation in crop foraging or distance to forest edge) by using a mixed model to assess if there was an interaction effect between population and human contact (i.e., distance to forest edge). Both populations had the same richness, but VNP monkeys had higher prevalence of infection and higher rates of multiple infection and groups that crop foraged or were near the forest edge had a higher prevalence of Capillaria infection. These results suggest that population density, forest edge permeability and human presence outside the forest increase infection risk in golden monkeys.
Dataset DOI: 10.5061/dryad.wh70rxx1r
Description of the data and file structure
We collected fecal samples from 4 golden monkey groups in Volcanoes National Park, Rwanda and 3 groups in Gishwati-Mukura National Park, Rwanda to explore the differences in helminth infection between the two parks and between groups in high vs low human contact. During day long focal follows a field team collected fecal samples from unique individuals in each group by locating the fecal bolus after witnessing defecation.
After collection, the team weighed the total mass of the fecal bolus and then took a 3 g subsample (when possible, minimum 1 g) for helminth identification. We used miniFLOTAC sedimentation to morphologically identify parasites down to the genus level and then counted the number of eggs of each helminth genus per miniFLOTAC chamber to calculate the eggs per gram feces and eggs per gram sediment.
Files and variables
File: Golden_monkey_parasite_data_for_Dryad_updated.xlsx
Description: An Excel file containing the data used to assess patterns of helminth infection in golden monkeys, including metadata. Four helminth taxa (Trichuris, Capillaria, Strongylid, and Strongyloides) were identified across the sample population and therefore the parasite load (based on egg counts) for each taxon was quantified for each monkey in the study.
Variables
- Sample ID - Unique identifier given to each sample (taken from a unique individual in the study population)
- Date - day on which the sample was collected
- Site - the National Park in which the sample was collected.
- Age/sex class - The age of the individual (classified as adult, sub-adult, or juvenile) combined with the sex of the individual. Juveniles were not assigned a sex because they were too young to display sex-specific characteristics.
- Group ID - The group to which the sampled individual belonged.
- Crop Forage? - Whether the group has been observed (by researchers or local farmers) to participate in crop foraging outside of the park. Coded as yes (Y) or no (N).
- Latitude - Latitude at which the sample was collected, recorded in decimal degrees within 10 m of accuracy.
- Longitude - Longitude at which the sample was collected, recorded in decimal degrees within 10 m of accuracy.
- Fecal bolus mass(g) - Mass in grams of the fecal bolus before any subsamples were taken.
- Sample mass (g) - Mass in grams of the fecal sub-sample used to search for, identify, and quantify helminth parasites.
- Sediment mass (g) - Mass in grams of sediment recovered from the fecal sample after flotation.
- MiniFlotac egg count Trichuris - total count of Trichuris eggs identified
- EPG Trichuris - number of Trichuris eggs found in one gram of feces, calculated from the total egg count and sample mass.
- EPGS Trichuris - number of Trichuris eggs found in one gram of sediment, calculated from the total egg count and sediment mass.
- MiniFlotac egg count Capillaria - total count of Capillaria eggs identified
- EPG Capillaria - number of Capillaria eggs found in one gram of feces, calculated from the total egg count and sample mass.
- EPGS Capillaria - number of Capillaria eggs found in one gram of sediment, calculated from the total egg count and sediment mass.
- MiniFlotac egg count Strongylids - total count of Strongylid eggs identified
- EPG Strongylids - number of Strongylids eggs found in one gram of feces, calculated from the total egg count and sample mass.
- EPGS Strongylids - number of Strongylids eggs found in one gram of sediment, calculated from the total egg count and sediment mass.
- MiniFlotac egg count Strongyloides - total count of Strongyloides eggs identified
- EPG Strongyloides - number of Strongyloides eggs found in one gram of feces, calculated from the total egg count and sample mass.
- EPGS Strongyloides - number of Strongyloides eggs found in one gram of sediment, calculated from the total egg count and sediment mass.
Abbreviations:
- EPG = Eggs per gram (feces)
- EPGS = Eggs per gram sediment
- GMNP = Gishwati-Mukura National Park
- VNP = Volcanoes National Park
- LUH = Large un-habituated
- SUH = Small un-habituated
- AF = Adult female
- AM = Adult male
- SAF = Sub-adult female
- SAM = Sub-adult male
- JUV = Juvenile
Code/software
The file can be viewed in any program that will read Microsoft Excel files. I analyzed the data in RStudio using the dplyr and glmm packages. The GPS coordinates can be viewed in QGIS or ArcGIS.
The data is from four golden monkey groups from Volcanoes National Park (VNP), Rwanda and three from Gishwati Forest of Gishwati-Mukura National Park, also in Rwanda. A field team collected fecal samples during daily follows in VNP from 30-May-2022 to 30-June-2022 and Gishwati Forest from 20-July-2022 to 14-September-2022. Immediately after witnessing a defecation event, the team located the fecal mass and recorded the group and age/sex class of the source monkey, and time and location of collection. Members of the field team were able to collect samples from unique individuals by identifying VNP monkeys by sight and collecting samples from individuals in different age-sex classes (juvenile, adult male, adult female) and/or individuals with unique identifiers (scars, stiff digits) in Gishwati Forest to avoice repeat sampling. The team then measured the total mass of each fecal bolus and then took a 3 g subsample which was stored in 10% formalin. (Full collection protocols can be found at https://www.protocols.io/view/golden-monkey-fecal-sampling-protocol-4r3l2o9ojv1y/v1.)
For morphological parasite identification, we homogenized and filtered 3 g fecal samples in 10% formalin, using a sugar solution, to separate eggs and larvae from the fecal matter. Once separated, we used a Mini-FLOTAC chamber to count the number of eggs in each chamber to estimate eggs per gram of feces. During flotation, we also identified helminth larvae to the genus level. Additional information can be found in the associated manuscript.