Soil-transmitted helminth eggs assessment in wastewater in an urban area in India.

Water quality and sanitation are inextricably linked to prevalence and control of soil-transmitted helminth infections, a public health concern in resource-limited settings. India bears a large burden of disease associated with poor sanitation. Transformative onsite sanitation technologies are being developed that feature elimination of pathogens including helminth eggs in wastewater treatment. We are conducting third-party testing of multiple sanitation technology systems in Coimbatore (Tamil Nadu) India. To ensure stringent testing of the pathogen removal ability of sanitation technologies, the presence of helminth eggs in wastewater across the town of Coimbatore was assessed. Wastewater samples from existing test sites as well as desludging trucks servicing residential and non-residential septic tanks, were collected. The AmBic methodology (based on washing, sieving, sedimenting and floating) was used for helminth egg isolation. We tested 29 different source samples and found a 52% prevalence of potentially infective helminth eggs. Identification and enumeration of helminth species is reported against the septage source (private residential vs. shared toilet facility) and total solids content. Trichuris egg counts were higher than those of hookworm and Ascaris from desludging trucks, whereas hookworm egg counts were higher in fresh wastewater samples. Surprisingly, no correlation between soil transmitted helminth eggs and total solids was observed.

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

BACKGROUND: The 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. METHODS: In 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. RESULTS: A 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. CONCLUSIONS: Malaria 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.

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.

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.

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.

Community Health Impacts of the Trident Copper Mine Project in Northwestern Zambia: Results from Repeated Cross-Sectional Surveys.

The application of a health impact assessment (HIA) for a large-scale copper mining project in rural Zambia triggered the long-term monitoring and evaluation of determinants of health and health outcomes in communities living in proximity to the mine. Three consecutive cross-sectional surveys were conducted at intervals of four years; thus, at baseline (2011), four (2015) and eight (2019) years into the project's development. Using the same field and laboratory procedures, the surveys allowed for determining changes in health indicators at the household level, in young children (<5 years), school attendees (9-14 years) and women (15-49 years). Results were compared between communities considered impacted by the project and communities outside the project area (comparison communities). The prevalence of Plasmodium falciparum infection increased in both the impacted and comparison communities between 2011 and 2019 but remained consistently lower in the impacted communities. Stunting in children < 5 years and the prevalence of intestinal parasite infections in children aged 9-14 years mostly decreased. In women of reproductive age, selected health indicators (i.e., anaemia, syphilis, underweight and place of delivery) either remained stable or improved. Impacted communities generally showed better health outcomes than comparison communities, suggesting that the health interventions implemented by the project as a consequence of the HIA have mitigated potential negative effects and enhanced positive effects. Caution is indicated to avoid promotion of health inequalities within and beyond the project area.

Gastrointestinal Parasites of Vervet Monkeys (Chlorocebus pygerythrus) in a High Latitude, Semi-Arid Region of South Africa.

Given a changing climate and large-scale human migration, understanding infectious diseases in wildlife and the factors that drive the spread of these diseases is becoming increasingly important. Owing to the close phylogenetic relationship between nonhuman primates and humans, primate parasites are of particular interest due to the potential for zoonotic disease transmission and for the study of social transmission within gregarious social groups. There is a wide range of social and environmental factors that influence the prevalence and transmission of pathogens, and identifying these, and their effects, is crucial to understanding the population-level consequences of climate change for animals that live in obligate social groups. Here we investigated gastrointestinal parasite species richness and used fecal egg counts to estimate worm intensities in 3 vervet monkey troops (Chlorocebus pygerythrus) in a high latitude, semi-arid region of South Africa. This region is characterized by unpredictable rainfall and temperature extremes in summer and winter. We identified the gastrointestinal parasites in the population and explored potential demographic predictors, namely sex and troop membership, of parasite species richness and estimated intensity. Additionally, we assessed whether there was short-term intra-individual, inter-sample consistency in egg counts. Six species of gastrointestinal helminths were identified from 3 study troops, with egg counts ranging from 0 eggs/g to 1,100 eggs/g. Neither age nor sex predicted species richness or estimated intensity. This population had the highest prevalence of parasites with an insect vector compared with all other vervet populations studied, and distinctively high prevalences of Trichostrongylus sp. (71%) and Ternidens sp. (27%). Additionally, we found intra-individual egg count consistency in the short term (mean: 32 days).

Predictors of Trypanosoma lewisi in Rattus norvegicus from Durban, South Africa.

This study investigated associations between Trypanosoma lewisi and Xenopsylla cheopis, a common cyclical vector of T. lewisi; Polyplax spinulosa, a reported mechanical vector; and Laelaps echidnina and Laelaps lamborni, 2 rodent mites of Rattus norvegicus in Durban, South Africa. In total, 379 R. norvegicus individuals were live-trapped at 48 sites in 4 locality types around Durban during a 1-yr period. Rats were euthanized, cardiac blood was taken to check for hemoparasites, and ectoparasites were removed for identification. Parasite species richness was higher in pups (2.11) and juveniles (1.02) than adults (0.87). Most rats in the study harbored 1 or 2 of the 5 parasites surveyed. Rats with trypanosomes and fleas were more prevalent in the city center and harbor, where juveniles were most affected. Rats with lice were more prevalent in informal settlements and urban/peri-urban areas, where pups had the highest infestations. There was a significant positive association between rats with fleas and trypanosomes and a negative association between rats with lice and trypanosomes. Location and rat age were significant predictors of T. lewisi, X. cheopis, and P. spinulosa. Mites showed no strong association with trypanosomes. Ectoparasite associations are possibly habitat and life-cycle related. We conclude that Durban's city center, which offers rats harborage, an unsanitary environment, and availability of food, is a high-transmission area for fleas and trypanosomes, and consequently a potential public health risk.

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.

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.