Colleen E. Archer

From Parasite Encounter to Infection: Multiple-Scale Drivers of Parasite Richness in a Wild Social Primate Population

Host parasite diversity plays a fundamental role in ecological and evolutionary processes, yet the factors that drive it are still poorly understood. A variety of processes, operating across a range of spatial scales, are likely to influence both the probability of parasite encounter and subsequent infection. Here, we explored eight possible determinants of parasite richness, comprising rainfall and temperature at the population level, ranging behavior and home range productivity at the group level, and age, sex, body condition, and social rank at the individual level. We used a unique dataset describing gastrointestinal parasites in a terrestrial subtropical vertebrate (chacma baboons, Papio ursinus), comprising 662 fecal samples from 86 individuals representing all age-sex classes across two groups over two dry seasons in a desert population. Three mixed models were used to identify the most important factor at each of the three spatial scales (population, group, individual); these were then standardized and combined in a single, global, mixed model. Individual age had the strongest influence on parasite richness, in a convex relationship. Parasite richness was also higher in females and animals in poor condition, albeit at a lower order of magnitude than age. Finally, with a further halving of effect size, parasite richness was positively correlated to day range and temperature. These findings indicate that a range of factors influence host parasite richness through both encounter and infection probabilities but that individual-level processes may be more important than those at the group or population level.

Gastrointestinal parasites of the chimpanzee population introduced onto Rubondo Island National Park, Tanzania.

The release of any species into a novel environment can evoke transmission of parasites that do not normally parasitize the host as well as potentially introducing new parasites into the environment. Species introductions potentially incur such risks, yet little is currently known about the parasite fauna of introduced primate species over the long term. We describe the results of long‐term monitoring of the intestinal parasite fauna of an unprovisioned, reproducing population of chimpanzees introduced 40 years earlier (1966–1969) onto Rubondo Island in Lake Victoria, Tanzania, a non‐native habitat for chimpanzees. Two parasitological surveys (March 1997–October 1998 and October 2002–December 2005) identified Entamoeba spp. including E. coli, Iodamoeba buetschlii, Troglodytella abrassarti, Chilomastix mesnili, Trichuris sp., Anatrichosoma sp., Strongyloides spp., Strongylida fam. gen. sp., Enterobius anthropopitheci, Subulura sp., Ascarididae gen. sp., and Protospirura muricola. The parasite fauna of the Rubondo chimpanzees is similar to wild chimpanzees living in their natural habitats, but Rubondo chimpanzees have a lower prevalence of strongylids (9%, 3.8%) and a higher prevalence of E. anthropopitheci (8.6%, 17.9%) than reported elsewhere. Species prevalence was similar between our two surveys, with the exception of Strongyloides spp. being higher in the first survey. None of these species are considered to pose a serious health risk to chimpanzees, but continued monitoring of the population and surveys of the parasitic fauna of the two coinhabitant primate species and other animals, natural reservoir hosts of some of the same parasites, is important to better understand the dynamics of host–parasite ecology and potential long‐term implications for chimpanzees introduced into a new habitat. Am. J. Primatol. 72:307–316, 2010.

The rat lung-worm Angiostrongylus cantonensis: a first report in South Africa

A study of the parasites of invasive rats in the eThekwini Municipality of KwaZulu-Natal has led to this first report of Angiostrongylus (Parastrongylus) cantonensis, commonly known as the rat lung worm, in South Africa. A. cantonensis is clearly endemic in this region and probably also in other areas of South Africa. There are a few reports of this nematode from Africa (excluding South Africa): in rats and snails in Egypt (Fouad and Abdulla, 1978), in snails in Nigeria (Sowemimo and Asaolur, 2004), and a human case from Ivory Coast (1980). As humans are accidental hosts, the parasite cannot complete its life cycle, and immature worms lodge in the central nervous system where they elicit a condition known as eosinophilic meningitis.

Household-based prevalence of helminths and parasitic protozoa in rural KwaZulu-Natal, South Africa, assessed from faecal vault sampling.

This study was undertaken to examine the family-based prevalence of environmentally persistent parasites in two rural communities of KwaZulu-Natal, South Africa. Samples were collected from 120 urine-diversion family toilets and screened for selected protozoa and helminths with immunomagnetic separation and the ammonium bicarbonate (AMBIC) protocol respectively. The parasites found were Ascaris lumbricoides (59%), Giardia intestinalis (54%), Trichuris trichiura (48%), Cryptosporidium spp. (21%) and Taenia spp. (18%). Only 14% of the household toilets were negative for these pathogens. The occurrence of A. lumbricoides and T. trichiura was lower (P<0.001) in the area with better hygiene behaviour, whereas G. intestinalis was more common (P<0.05) in families with at least one child aged five years or less and in families with more than four persons. Quantification of the parasites per gram was done for each sample and this provided realistic risk assessment data for the reuse of material from urine-diversion toilets. The high occurrence of parasites found in the two communities, in spite of sanitation and hygiene interventions in the areas, suggests an endemicity that will not be reduced without de-worming campaigns. Finally, the study showed that sampling directly from the deposited faecal material may be useful for parasitic prevalence estimations.

The epidemiology of malaria and anaemia in the Bonikro mining area, central Côte d’Ivoire

BackgroundThe epidemiology of malaria and anaemia is characterized by small-scale spatial and temporal heterogeneity, which might be influenced by human activities, such as mining and related disturbance of the environment. Private sector involvement holds promise to foster public health, including the prevention and control of malaria and anaemia. Here, results from a cross-sectional epidemiological survey, conducted in communities that might potentially be affected by the Bonikro Gold Mine (BGM) in Côte d’Ivoire, are reported.MethodsIn December 2012, a cross-sectional survey was carried out in seven communities situated within a 20-km radius of the BGM in central Côte d’Ivoire. Capillary blood samples were obtained from children aged six to 59 months. Samples were subjected to a rapid diagnostic test (RDT) for Plasmodium falciparum detection, whilst haemoglobin (Hb) was measured to determine anaemia. Additionally, mothers were interviewed with a malaria-related knowledge, attitudes and practices questionnaire.ResultsA total of 339 children and 235 mothers participated in the surveys. A positive RDT for P. falciparum was found in 69% of the children, whilst 72% of the children were anaemic (Hb <11 g/dl). Plasmodium falciparum infection was significantly associated with anaemia (odds ratio (OR) 7.43, 95% confidence interval (CI) 3.97-13.89), access to a health facility (OR 5.59, 95% CI 1.81-17.32) and age (OR 0.04, 95% CI 0.01-0.12; youngest (six to 11 months) versus oldest (48-59 months) age group). Less than a quarter of mothers knew that malaria is uniquely transmitted by mosquitoes (22.3%, 95% CI 16.8-27.7%). Misconceptions were common; most of the mothers believe that working in the sun can cause malaria.ConclusionsMalaria and anaemia are highly endemic in the surveyed communities around the BGM project area in Côte d’Ivoire. The data presented here provide a rationale for designing setting-specific interventions and can be utilized as a benchmark for longitudinal monitoring of potential project-related impacts due to changes in the social-ecological and health systems.

Parasite Transmission Risk From Geophagic and Foraging Behavior in Chacma Baboons

Numerous behavioral and ecological factors are associated with parasite transmission. One factor explored in human research, but absent from nonhuman primate research, is parasite transmission from soil ingestion. Human studies suggest geophagy, the regular and deliberate consumption of soil, increases risk of soil‐transmitted helminth (STH) infection. Geophagy, which is prevalent in nonhuman primates, has several positive associations: gastrointestinal distress alleviation, possible mineral supplementation, and bacterial infection prevention. Our objective was to determine whether STH transmission was possible from deliberate or accidental soil ingestion, in a troop of chacma baboons (Papio hamadryas ursinus) that engaged in geophagy, foraged on the terrestrial substrata, and had a Trichuris sp. sample prevalence of 100%. We collected and analyzed 80 soil samples from geophagy and ground foraging sites on and around Wildcliff Nature Reserve, South Africa. Forty soil samples were collected from sites where soil was consumed, and 40 were collected from sites where soil was not consumed. At geophagy sites, the number of Trichuris sp. eggs recovered varied significantly between areas used and unused by the baboons, suggesting behavior is an important factor. In contrast, at foraging sites, there was only a tendency to recover more eggs at used than unused areas, and we propose egg recovery was influenced by fecal contamination that occurred throughout foraging stands. The difference in egg recovery between used areas at geophagy sites and used areas at foraging sites was not significant. These preliminary findings suggest both geophagy and foraging sites are a potential source of STH infection for this troop. Whether geophagy benefits outweigh the potential cost of parasite reinfection for this baboon troop is unknown, so we encourage future research on the influence that host foraging behavior may have on parasite reinfection. Am. J. Primatol. 74:940‐947, 2012.

Viscous heating effect on deactivation of helminth eggs in ventilated improved pit sludge.

Viscous heating by extrusion of faecal material obtained from ventilated improved pit (VIP) latrines can be used to deactivate soil-transmitted helminth (STH) eggs by increasing the temperature of faecal sludge uniformly. Viscous heating can deactivate STH eggs present in sludge to make the material safer to transport, dispose of, or use in agricultural applications or as an energy source. The mechanical energy required to generate the shear rate can originate from any source. No other heat source or additive is required. Here we determined a baseline for the deactivation of STH eggs using viscous heating. To characterize equipment performance, three parameters were investigated: (1) minimum temperature required for deactivation; (2) local maximum temperatures for various flow rates and moisture contents (MCs); and (3) thermal efficiency. Excess water is undesirable since low viscosities require extended residence time and increased energy input. The minimum temperature to achieve greater than 90% helminth egg deactivation is 70 °C. For the laboratory-scale equipment tested, the maximum allowable mass flow rate for VIP sludge with 77% MC was found to be 3.6 g/s.

Monitoring of Selected Health Indicators in Children Living in a Copper Mine Development Area in Northwestern Zambia

The epidemiology of malaria, anaemia and malnutrition in children is potentially altered in mining development areas. In a copper extraction project in northwestern Zambia, a health impact assessment (HIA) was commissioned to predict, manage and monitor health impacts. Two cross-sectional surveys were conducted: at baseline prior to project development (2011) and at four years into development (2015). Prevalence of Plasmodium falciparum, anaemia and stunting were assessed in under-five-year-old children, while hookworm infection was assessed in children aged 9–14 years in communities impacted and comparison communities not impacted by the project. P. falciparum prevalence was significantly higher in 2015 compared to 2011 in both impacted and comparison communities (odds ratio (OR) = 2.51 and OR = 6.97, respectively). Stunting was significantly lower in 2015 in impacted communities only (OR = 0.63). Anaemia was slightly lower in 2015 compared to baseline in both impacted and comparison communities. Resettlement due to the project and migration background (i.e., moving into the area within the past five years) were generally associated with better health outcomes in 2015. We conclude that repeated cross-sectional surveys to monitor health in communities impacted by projects should become an integral part of HIA to deepen the understanding of changing patterns of health and support implementation of setting-specific public health measures.

Schistosomiasis and soil-transmitted helminth infections in schoolchildren in north-eastern Democratic Republic of the Congo

BACKGROUND There is a paucity of epidemiological data pertaining to schistosomiasis and soil-transmitted helminth (STH) infections in the Democratic Republic of the Congo (DRC). METHODS A cross-sectional survey was carried out in the north-eastern part of DRC enrolling 400 schoolchildren aged 9-14 years. Stool and urine samples were subjected to standard diagnostic methods and examined under a microscope for helminth eggs. RESULTS Four out of five children were infected with at least one helminth species. Schistosoma mansoni was the predominant species (57.8%). Urine examinations were all negative for S. haematobium. CONCLUSIONS S. mansoni and STH infections are highly endemic in the surveyed part of the DRC, calling for interventions in school-aged children.

Endo-parasites of public-health importance recovered from rodents in the Durban metropolitan area, South Africa

Background: Parasite infections of public health importance carried by Rattus spp. on the African continent (excluding toxoplasmosis) have not been adequately researched. The aim of this study was to investigate endoparasites of public health importance, particularly those associated with R. norvegicus, at different locations and seasons within the port-city, Durban.Methods: Four hundred rodents (379 R. norvegicus, 10 R. rattus and 11 Mastomys natalensis) were live-trapped at 60 sites in four locations, during wet and dry seasons in 2009. Rats were humanely euthanased, cardiac blood drawn (for blood smears and serology), ectoparasites removed and dissected. Each organ was separately processed to collect parasites. Binary logistic regression and four-way ANOVAs were used to test for the effects of location, season, rodent age and gender on parasite prevalence, richness and abundance.Results: Eight parasites of public health importance were detected: Gongylonema sp. (25.3%), Trypanosoma lewisi (22.8%), Hyme...