Fig 1.
Home range and habitat of chimpanzees in Bulindi, Hoima District, Uganda.
(a) Map adapted from Landsat imagery courtesy of USGS/NASA Landsat. The most commonly used portion of the home range is indicated by the yellow oval. Dark green areas are fragments of riverine forest, Cyperus papyrus swamp, regenerating bush and woodland; the surrounding matrix comprises smallholder farmland, homes and trading centres. The thin line at centre is a main road connecting Hoima and Masindi towns. (b) Typical view of narrow riverine forest dominated by tall Phoenix reclinata palms; a chimpanzee is visible in a small tree above the water. (c) Two adult males of the Bulindi community travelling across farmland while a local farmer (visible between the two chimpanzees) tends to his garden.
Table 1.
Prevalence of microscopic and macroscopic gastrointestinal parasite taxa in faeces of chimpanzees in Bulindi, Uganda, during the two survey periods (1 = Sep–Nov 2012; 2 = Feb–Apr 2013).
Fig 2.
Gastrointestinal parasites and symbionts found from coproscopic analysis of faeces of chimpanzees in Bulindi, Uganda.
(a) Protozoa: 1. Troglodytella abrassarti; 2. Balantidium coli (trophozoite); 3. Balantidium coli (cyst); 4. Troglocorys cava; 5. Entamoeba coli; 6. Entamoeba sp.; 7. Iodamoeba buetschlii; 8. Giardia intestinalis; 9. Chilomastix mesnili; 10. Blastocystis sp. (b) Helminths: 11. Dicrocoeliidae gen. sp.; 12. Bertiella sp.; 13. Spiruridae gen. sp.; 14. Hookworm; 15. Oesophagostomum sp.; 16. Strongyloides sp. (egg); 17. Strongyloides sp. (larva); 18. Probstmayria gombensis (adult).
Table 2.
Summary of DNA sequence analysis of larval nematodes from coprocultures (n = 38).
Fig 3.
Variation in parasite prevalence in relation to rainfall, temperature and humidity.
Climate data are shown for the period August 2012–April 2013, spanning both survey periods and beginning one month prior to period 1. Top: Biweekly mean daily maximum and minimum temperature and % relative humidity (RH); Middle: Biweekly rainfall and % faecal samples positive for nematodes (hookworm, Oesophagostomum sp., Probstmayria gombensis and Strongyloides sp.). Bottom: Biweekly rainfall and % faecal samples positive for protozoan parasites (Balantidium coli, Blastocystis sp., Entamoeba coli, Entamoeba sp., Troglocorys cava, Troglodytella abrassarti). The patterning of rainfall bars indicate whether biweekly periods were in months classified as wet (solid), transient (hatched) or dry (vertical lines); see Methods. Only parasites detected in >5% of samples (n = 432) are shown; for the number of faecal samples analysed per biweekly period, see Supporting Information S1 Data File.
Table 3.
Parasite prevalence in wet months (>100 mm rainfall) and dry and transient months (≤100 mm rainfall) compared.
Fig 4.
Multidimensional scaling (MDS) model of independent associations among parasites and climate.
The first-order dimension represents a stronger association than the second-order dimension. The first dimension represents a combination of high rainfall and humidity (on the positive scores) and high temperature (negative scores) while the second represents a combination of high and low temperatures. The closer two or more variables are, the more likely they covary independently of other points on the map. Colours differentiate groups of variables that show some degree of association in relation to other variables in the map. Only parasite taxa that showed a significant difference in prevalence between survey periods were selected for the model (see Table 1).
Fig 5.
Multidimensional scaling (MDS) model of independent associations among parasites.
The first-order dimension represents a stronger association than the second-order dimension. The closer two or more variables are, the more likely they covary independently of other points on the map. Colours differentiate groups of variables that show some degree of association in relation to other variables in the map. Only parasites detected in >5% of faecal samples were included in the model.
Table 4.
Within-host associations among parasites in chimpanzee faecal samples in Bulindi a.
Fig 6.
Chimpanzees in Bulindi commonly swallow whole bristly leaves of Aneilema nyasense C.B. Clarke (Commelinaceae).
(a) A. nyasense growing in riverine forest in Bulindi. (b) 30 undigested and unchewed leaves of A. nyasense recovered from one chimpanzee faecal specimen; the leaves are passed in faeces folded one or more times, but have been unfolded manually here for identification. No adult worms were observed together with the leaves in this faecal sample.
Fig 7.
Temporal variation in leaf swallowing in relation to parasite infections and rainfall during the two survey periods.
Top: bars show the biweekly mean (± SD) number of infections by different parasites with pathogenic potential, determined by coproscopy (see text). Bottom: Lines show the % biweekly faeces containing wholly swallowed leaves and the biweekly prevalence in samples of potentially pathogenic nematodes (Oesophagostomum sp., Strongyloides sp. and hookworm); bars show biweekly rainfall. The patterning of rainfall bars indicate whether biweekly periods were in months classified as wet (solid), transient (hatched) or dry (vertical lines); see Methods. The number of faecal samples inspected per biweekly period (microscopically; macroscopically): Period 1 –Sep.2 (33; 28), Oct.1 (46; 43), Oct.2 (30; 30), Nov.1 (32; 33), Nov.2 (31; 30); Period 2 –Feb.2 (14; 21), Mar.1 (91; 81), Mar.2 (65; 61), Apr.1 (55; 46), Apr.2 (35; 33).
Fig 8.
Multidimensional scaling (MDS) model of independent associations among whole leaf swallowing, rainfall, and six parasites with known or likely pathogenicity.
The first-order dimension represents a stronger association than the second-order dimension. The closer two or more variables are, the more likely they covary independently of other points on the map. Colours differentiate groups of variables that show some degree of association in relation to other variables in the map.