Epidemiological Significance of Parasitic Infections in Olive Baboons (Papio anubis) at Gombe National Park, Tanzania

Several parasites of significant health importance have been observed in baboons at Gombe National Park in western Tanzania. However, little is known on impacts these infections have on baboon health. Baboon stools were examined for parasites using formol-ethyl technique and their health and troop membership associated with parasitic infections. Observed nematode parasites were; Streptopharagus sp., Physaloptera sp., unidentified nematodes, hookworms and Trichuris sp. Trematode parasites included Schistosoma mansoni and unidentified trematode, with the latter’s intensity being highest in DB troop baboons. Parasite egg counts (epg) for nematodes ranged from 9 to 12, and that of trematodes from 4 to 40 epg. Trichuris sp. was most prevalent while Streptopharagus sp. was least common. Female baboons in crab-feeding C troop had significantly lower body weight than others (p < 0.05). The present observation of schistosomiasis in Gombe baboons suggests the disease may have been maintained among the animals since its introduction in the park in the 1980s. Baboons in C and DB troops in Gombe are most likely infected with food-borne unidentified trematodes. For years, the baboons have remained constant in size and are emaciated and weak-looking suggesting that there is probably a link between the parasites and the animals’ poor health.Keywords: Parasitic infections, baboon health. Keywords: Parasitic infections; baboon health; trematodes; Gombe

Distribution patterns of gastrointestinal parasites in vervet monkeys (Chlorocebus pygerythrus) at Gombe national park, Tanzania

Vervet monkeys at Gombe National Park in western Tanzania constitute a key component of the park’s ecosystem through interactions with other animals and people in the area. However, the parasite fauna of these animals has not been investigated. Thus, 21 faecal samples obtained from the animals in September 2010 were examined for parasites using formol-ethyl technique. The parasites observed included Trichuris spp., Physaloptera spp., hookworms and unidentified nematodes. While egg counts for unidentified nematodes did not vary with vervet monkey communities (z = 0.759, p = 0.448), other parasites were significantly higher among vervets at north of the park near Mwamgongo village compared to those at southern park border close to Mtanga village (Trichuris spp.: z = 2.443, p = 0.0146; Hookworms: z = 2.084, p = 0.0371). This is the first baseline study on vervet monkey parasites at Gombe and it broadens our understanding of the animals’ ecology and health. The observed parasites namely Trichuris and hookworms are also common in human populations in the area, and this suggests a potential health risk given the existing animal-human interactions. This stresses the need to better understand how these findings may relate to wildlife conservation and public health in the areaKey words: Vervet monkeys, Gombe ecosystem, parasites

Epidemiology of Schistosoma mansoni infection in sympatric humans and non-human primates in the Gombe ecosystem Tanzania

Increased interactions between humans and wild animals in and around protected areas have raised the risks for sharing diseases and parasites among them. Regular surveillance with intervention for these infections in such areas is therefore necessary for improving animal health and for controlling any spill-over of animal diseases into nearby human populations. Although both humans and non-human primates in the Gombe area in western Tanzania are infected with schistosomiasis, it is not known whether strains of their schistosomes are epidemiologically and genetically distinct. The distribution and transmission risk factors for the disease in these areas are also not well known. This study investigated the infection patterns of schistosomiasis in humans and non-human primates in Gombe National Park and surrounding villages of Mwamgongo, Bugamba, Kiziba and Mtanga and related the infection prevalence and intensity to locality and other demographic characteristics such as age and sex in humans. It also examined the dosage and number of praziquantel tablets administered to school children based on their weight and compared this to the dosage they would receive based on their height. The parasite fauna of baboons and vervet monkeys in Gombe was also examined to determine the parasite species assess whether their infection levels have changed over time. Snails were also sampled so as to gain a clear understanding of the species present in an area, their local distribution and infection status. The results showed a significant variation of S. mansoni prevalence between age groups in humans, which also depended on site. The parasite egg counts (intensity) also varied significantly between age groups and across study sites. The dosage range of praziquantel in mg per kg of bodyweight predicted by height was 23-43 (average: 35.2) while the dosage range given to children based on their weight was 29-78 (average: 45.2) and this variation was statistically significant (p > 0.0001). Overall, six children (5.3%) received a praziquantel dosage below the recommended range (30-60 mg/kg) based on their weight while two children (2.6%) would have received the drugs above the optimum range based on their height. The parasites identified in baboons and vervets included Trichuris spp., Physaloptera spp., hookworms and unidentified nematodes, while Paragonimus spp., Streptopharagus spp. and Schistosoma mansoni were exclusively detected in baboons. Molecular analysis of baboon schistosome eggs confirmed them to be S. mansoni. A GLM analysis indicated that the interaction between season and baboon troop was a significant predictor of parasite prevalence and intensity in baboons. Snails obtained from all streams except at Mtanga were identified as Biomphalaria pfeifferi based on morphology and DNA analysis. These findings indicate a high infection of intestinal schistosomiasis in these areas of western Tanzania, suggesting that the distribution of the disease in the country could be more widespread than previously thought. The results also confirm that the infection of intestinal schistosomiasis in the area is focal, with marked variations between adjacent villages. The study shows that while both weight and height estimate the amount of praziquantel dosage that is within an acceptable range, weight tends to underestimate the drug while height slightly overestimates it. It is therefore essential to conduct further field studies to test the usefulness of the dose pole in praziquantel distribution and evaluate the extent to which the method could be wasting the drug by giving more than the necessary dosage. As most parasites diagnosed in baboons and vervets are capable of infecting humans, these animals can potentially serve as reservoirs of human helminths given the regular human-wildlife interactions in the area. The implication of these observations to wildlife conservation and public health issues in the area has been explored

Knowledge, Attitudes and Practices on Urinary Schistosomiasis-Related Morbidity among Communities in Itilima District, Tanzania

Long-term infections by urinary schistosomiasis can result in urinary tract morbidities and increase the threats to public health. Information on the community’s knowledge, attitudes, and practices (KAP) on various aspects of urinary schistosomiasis, caused by Schistosoma haematobium has been lacking in Itilima District, which is likely to perpetuate the transmission of the disease and its negative health consequences. This study assessed knowledge, attitudes and practices on schistosomiasis-related morbidities in Itilima District from February to June 2021. A cross-sectional survey using a structured questionnaire was used, and a total of 657 participants were involved in the study. A total of 575 participants (87.5%) had awareness on schistosomiasis compared to 82 (12.5%) who were not aware of the disease, and this variation was statistically significant (x² = 369.938, DF = 1, p < 0.001). The relationship between urinary schistosomiasis and its related morbidities was known by 111 (16.9%) respondents, while 546 (83.1%) knew nothing about it, and this variation was also statistically significant (c2 = 388.166, DF = 1, p < 0.001). It can be concluded that knowledge of urinary schistosomiasis and its related morbidities among the communities was limited. This is possibly because knowledge of infection stages of S. haematobium that causes the morbidity requires an understanding of disease etiology. Therefore, this study recommends that interventions to impart knowledge on schistosomiasis and the associated morbidities should be implemented in Itilima District. Keywords:     Schistosomiasis, Urinary tract morbidity, Knowledge, Attitudes and Practices, Itilima Distric

Demographic Factors Driving Schistosomiasis and Soil-Transmitted Helminthiases in Milola Ward, Lindi District, Tanzania: A Useful Guide for Launching Intervention Programmes

Background: Current information on the distribution of and risk factors for schistosomiasis and soil-transmitted helminthiases is scarce for most areas of southern Tanzania, including Milola Ward in Lindi District. This study was initiated to establish the status of these infections in Milola Ward and to assess how they vary with demographic factors.   Methods: From September to October 2014, 2 sets of stool and urine samples were collected from residents of Milola Ward. The Kato–Katz technique was used to examine stool samples for faecal-borne parasites, and the filtration technique was used to examine urine for urinary schistosomes. A total of 195 individuals aged 5 to 90 years were enrolled in the study; 190 (97%) participants submitted adequate urine samples, of whom 107 (56%) were female and 83 (43%) were male. Of the 195 participants who took part in the initial sampling exercise, 158 (81%) provided adequate stool samples; 121 (77%) of these were adults, and the rest (n=37, 23%) were children. Only 53 urine and 26 faecal samples were obtained in the second round of sampling, and due to marked inconsistencies, these have been excluded from the analysis. Mean parasite abundance was analysed for its association with demographic factors, such as age and sex.   Results: Three varieties of parasite were detected, namely, Schistosoma haematobium in 44 (23%) of 190 urine samples, hookworms in 12 (8%) of 158 stool samples, and Trichuris trichiura in 6 (4%) of 158 stool samples. The difference in S. haematobium prevalence between male and female participants (27 of 107 females, 25% vs 17 of 83 males, 20%) was not statistically significant (Kruskal–Wallis test, P=.47). Linear regression analysis of S. haematobium infection with age showed a significant association, with children having higher infection intensities than adults (P<.001). S. haematobium prevalence and intensity did not vary significantly between villages (intensity [Kruskal–Wallis test], P=.95; prevalence, P=.88).   Discussion: These data confirm that in this setting, the mean age of peak helminthiasis prevalence decreases as transmission pressure increases, with non-school children below 18 years old being most at risk of acquiring parasitic infections. This was the first baseline survey of parasitic infections in Milola Ward, so the results will be crucial for guiding control efforts against parasitic diseases in the area

One Health and Neglected Tropical Diseases—Multisectoral Solutions to Endemic Challenges

One Health is defined as an approach to achieve better health outcomes for humans, animals, and the environment through collaborative and interdisciplinary efforts [...

One Health and Neglected Tropical Diseases—Multisectoral Solutions to Endemic Challenges

One Health is defined as an approach to achieve better health outcomes for humans, animals, and the environment through collaborative and interdisciplinary efforts. Increasingly, the One Health framework is being applied to the management, control, and even elimination of neglected tropical diseases (NTDs). NTDs are a set of debilitating and often chronic infectious diseases that, collectively, affect more than one billion people in almost 150 countries, with disproportionate impact on the extremely poor [1,2]. In this Special Issue, we present a diverse body of work united under the One Health ideology and a desire to mitigate the devastating effects of NTDs. The numerous diseases, methodologies, and landscapes presented highlight the interconnected and increasingly overlapping existence of humans, animals, and their pathogens

Summary of apparent prevalence of schistosome eggs in participants sampled from Gombe National Park and its neighbouring villages: actively sampled (school children), passively sampled (self-selected adults), and accompanying children (non-school children that were sampled along with the passively sampled adults).

<p>Summary of apparent prevalence of schistosome eggs in participants sampled from Gombe National Park and its neighbouring villages: actively sampled (school children), passively sampled (self-selected adults), and accompanying children (non-school children that were sampled along with the passively sampled adults).</p

Estimating the prevalence and intensity of <i>Schistosoma mansoni</i> infection among rural communities in Western Tanzania: The influence of sampling strategy and statistical approach

<div><p>Background</p><p><i>Schistosoma mansoni</i> is a parasite of major public health importance in developing countries, where it causes a neglected tropical disease known as intestinal schistosomiasis. However, the distribution of the parasite within many endemic regions is currently unknown, which hinders effective control. The purpose of this study was to characterize the prevalence and intensity of infection of <i>S</i>. <i>mansoni</i> in a remote area of western Tanzania.</p><p>Methodology/Principal findings</p><p>Stool samples were collected from 192 children and 147 adults residing in Gombe National Park and four nearby villages. Children were actively sampled in local schools, and adults were sampled passively by voluntary presentation at the local health clinics. The two datasets were therefore analysed separately. Faecal worm egg count (FWEC) data were analysed using negative binomial and zero-inflated negative binomial (ZINB) models with explanatory variables of site, sex, and age. The ZINB models indicated that a substantial proportion of the observed zero FWEC reflected a failure to detect eggs in truly infected individuals, meaning that the estimated true prevalence was much higher than the apparent prevalence as calculated based on the simple proportion of non-zero FWEC. For the passively sampled data from adults, the data were consistent with close to 100% true prevalence of infection. Both the prevalence and intensity of infection differed significantly between sites, but there were no significant associations with sex or age.</p><p>Conclusions/Significance</p><p>Overall, our data suggest a more widespread distribution of <i>S</i>. <i>mansoni</i> in this part of Tanzania than was previously thought. The apparent prevalence estimates substantially under-estimated the true prevalence as determined by the ZINB models, and the two types of sampling strategies also resulted in differing conclusions regarding prevalence of infection. We therefore recommend that future surveillance programmes designed to assess risk factors should use active sampling whenever possible, in order to avoid the self-selection bias associated with passive sampling.</p></div

Fitted estimates and p-values for the relevant effects estimated from the final NB model for the passively sampled data.

<p>Note that there are no zero-inflation terms for the NB model because any observed zeros are assumed to reflect a failure to detect eggs in truly infected individuals.</p