The trend of schistosomiasis related bladder cancer in the lake zone, Tanzania: a retrospective review over 10 years period.

INTRODUCTION: Bladder cancer is a possible outcome of chronic urinary schistosomiasis in many endemic countries. In Tanzania, the Lake Victoria area is one of the areas with the highest prevalence of urinary schistosomiasis and higher incidences of squamous cell carcinoma (SCC) of the urinary bladder. A previous study in the area over one decade (2001-2010) showed SCC to be common in patients aged below 50 years. With various prevention and intervention programs there are likely to be notable changes in schistosomiasis-related urinary bladder cancer, which is currently unknown. Updated information on the status of SCC in this area will be useful for giving an insights into efficacy of control interventions implemented and help guide the initiation of new ones. Therefore, this study was done to determine the current trend of schistosomiasis-related bladder cancer in lake zone, Tanzania. METHODS: This was a descriptive retrospective study of histologically confirmed urinary bladder cancer cases diagnosed at the Pathology Department of Bugando Medical Centre over 10 years period. The patient files and histopathology reports were retrieved and information was extracted. Data were analyzed using Chi-square and student t-test. RESULTS: A total of 481 patients were diagnosed with urinary bladder cancer during the study period whereby, 52.6% were males and 47.4% were females. The mean age regardless of histological type of cancer was 55 ± 14.2 years. The SCC was the commonest histological type accounting for 57.0%, followed by transitional cell carcinoma 37.6%, and 5.4% were adenocarcinomas. The Schistosoma haematobium eggs were observed in 25.2% and were commonly associated with SCC (p = 0.001). Poorly differentiated cancers were observed mostly in females (58.6%) compared to males (41.4%) (p = 0.003). Muscular invasion of the urinary bladder by cancer was observed in 11.4% of the patients, and this was significantly higher in non-squamous than in squamous cancers (p = 0.034). CONCLUSION: Schistosomiasis-related cancers of the urinary bladder in the Lake zone of Tanzania is still a problem. Schistosoma haematobium eggs were associated with SCC type indicating the persistence of infection in the area. This calls for more efforts on preventive and intervention programs to reduce the burden of urinary bladder cancer in the lake zone.

Climate Change Vulnerability Assessment for the Rondo Dwarf Galago in Coastal Forests, Tanzania.

Negative effects of climate change on organisms and their habitats pose significant conservation challenges especially for species already under siege from other threats like habitat loss, pollution and diseases. This study assessed the extent to which the Rondo dwarf galago (Paragalago rondoensis), an endangered primate in the coastal forests in eastern Tanzania is threatened by climate change. Past and projected temperature and precipitation records from Tanzania Meteorological Authority were overlaid with P. rondoensis distribution range to assess the species exposure to climate extremes. Traits predisposing it to climate change were also obtained from published literature and experts on the organism's biology to determine its sensitivity. The P. rondoensis vulnerability to climate change was obtained by feeding exposure and sensitivity data into Natureserve's Climate Change Vulnerability Index (CCVI) software. Results indicated that most of Rondo galago's habitat and distribution range will be exposed to a temperature increase of 1 to 1.3 °C by 2050, which if combined with other threats, is likely to further endanger the species survival. Due to its diet specialization on insects, which are moisture-dependent, any extreme decrease in humidity will reduce its diet availability thereby threatening the species further. Moreover, Rondo galago's limited habitats and distribution range in the East African tropical coastal forests, raises the species threat level. Rondo galago's conservation should be enhanced through creation of corridors to facilitate its possible shifts to conducive and safer habitats in the event of extreme weather. Climate change aspects should also be integrated into the species conservation strategies.

The Gombe Ecosystem Health Project: 16 years of program evolution and lessons learned.

Infectious disease outbreaks pose a significant threat to the conservation of chimpanzees (Pan troglodytes) and all threatened nonhuman primates. Characterizing and mitigating these threats to support the sustainability and welfare of wild populations is of the highest priority. In an attempt to understand and mitigate the risk of disease for the chimpanzees of Gombe National Park, Tanzania, we initiated a long-term health-monitoring program in 2004. While the initial focus was to expand the ongoing behavioral research on chimpanzees to include standardized data on clinical signs of health, it soon became evident that the scope of the project would ideally include diagnostic surveillance of pathogens for all primates (including people) and domestic animals, both within and surrounding the National Park. Integration of these data, along with in-depth post-mortem examinations, have allowed us to establish baseline health indicators to inform outbreak response. Here, we describe the development and expansion of the Gombe Ecosystem Health project, review major findings from the research and summarize the challenges and lessons learned over the past 16 years. We also highlight future directions and present the opportunities and challenges that remain when implementing studies of ecosystem health in a complex, multispecies environment.

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 [...].

Socioecological correlates of clinical signs in two communities of wild chimpanzees (Pan troglodytes) at Gombe National Park, Tanzania.

Disease and other health hazards pose serious threats to the persistence of wild ape populations. The total chimpanzee population at Gombe National Park, Tanzania, has declined from an estimated 120 to 150 individuals in the 1960's to around 100 individuals by the end of 2013, with death associated with observable signs of disease as the leading cause of mortality. In 2004, we began a non-invasive health-monitoring program in the two habituated communities in the park (Kasekela and Mitumba) with the aim of understanding the prevalence of health issues in the population, and identifying the presence and impacts of various pathogens. Here we present prospectively collected data on clinical signs (observable changes in health) in the chimpanzees of the Kasekela (n = 81) and Mitumba (n = 32) communities over an 8-year period (2005-2012). First, we take a population approach and analyze prevalence of clinical signs in five different categories: gastrointestinal system (diarrhea), body condition (estimated weight loss), respiratory system (coughing, sneezing etc.), wounds/lameness, and dermatologic issues by year, month, and community membership. Mean monthly prevalence of each clinical sign per community varied, but typically affected <10% of observed individuals. Secondly, we analyze the presence of clinical signs in these categories as they relate to individual demographic and social factors (age, sex, and dominance rank) and simian immunodeficiency virus (SIVcpz) infection status. Adults have higher odds of being observed with diarrhea, loss of body condition, and wounds or lameness when compared to immatures, while males have a higher probability of being observed with wounds or lameness than females. In contrast, signs of respiratory illness appear not to be related to chimpanzee-specific factors and skin abnormalities are very rare. For a subset of known-rank individuals, dominance rank predicts the probability of wounding/lameness in adult males, but does not predict any adverse clinical signs in adult females. Instead, adult females with SIVcpz infection are more likely to be observed with diarrhea, a finding that warrants further investigation. Comparable data are needed from other sites to determine whether the prevalence of clinical signs we observe are relatively high or low, as well as to more fully understand the factors influencing health of wild apes at both the population and individual level. Am. J. Primatol. 80:e22562, 2018. © 2016 Wiley Periodicals, Inc.

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.

Assessing S. mansoni prevalence in Biomphalaria snails in the Gombe ecosystem of western Tanzania: the importance of DNA sequence data for clarifying species identification.

BACKGROUND: Snails are essential for the transmission and maintenance of schistosomiasis in endemic areas, as they serve as intermediate hosts for schistosome parasites. A clear understanding of the snail species present, their local distribution and infection status is therefore a prerequisite for effective control of schistosomiasis. The purpose of this study was to establish the infection status and distribution of Schistosoma mansoni in snails in the Gombe area along the shores of Lake Tanganyika in western Tanzania, using both detection of cercarial shedding and molecular approaches. METHODS: Snails were collected from streams located close to human settlements in Gombe National Park, as well as from nearby villages (Kiziba, Mtanga, Mwamgongo and Bugamba) and the largest town in the region (Kigoma). Snails were individually exposed to light to induce shedding of schistosome larvae, which were examined using a compound light microscope. Additionally, the internal transcribed spacer (ITS) region of the ribosomal RNA gene cluster was simultaneously amplified in both snails and their trematodes using a single polymerase chain reaction (PCR) and sequenced to confirm species identification. RESULTS: Snails morphologically identified as Biomphalaria pfeifferi were present in all streams except at Mtanga but their distribution was patchy in both time and space. Sequencing of PCR products indicated that not all snails were B. pfeifferi. None of the snails from Gombe or Bugamba shed schistosome larvae, while larvae were shed at all other sites. Overall, an infection prevalence of only 12% was observed in snails based on cercarial shedding. While 47% of the snails were PCR-positive for the 500 bp ITS fragment, which was predicted to indicate infection with S. mansoni, sequence data demonstrated that these bands are not species-specific and can be amplified from other trematode infections. In addition, a 1000 bp band was amplified in 14% of samples, which was identified as a trematode in the family Derogenidae. CONCLUSIONS: The results support the previous assumption that B. pfeifferi snails may be involved in transmitting schistosomiasis in the area but suggest that the community structure of both snails and trematodes may be more complicated than previously thought. This emphasises the importance of confirming species identifications using sequencing, rather than relying only on PCR-based diagnostics or cercarial shedding.

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

BACKGROUND: Schistosoma mansoni 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 S. mansoni in a remote area of western Tanzania. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: Overall, our data suggest a more widespread distribution of S. mansoni 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.

Extent of morbidity associated with schistosomiasis infection in Malawi: a review paper.

Data on the extent of the burden due to schistosomiasis is sparse in most Sub-Saharan African countries. However, this data is crucial for triggering medical attention. A review of extent of morbidity and determinants associated with schistosomiasis in Malawi was therefore conducted to quantify the infection in order to concretise the need for medical intervention. A systematic and traditional search strategy was used to find literature for the review, whilst exclusion and inclusion criteria were used to identify appropriate articles. Logistic regression curves of epidemiological model Y = (a + bx (c) )/(1 + bx (c) ) and the recommendation that schistosomiasis prevalence can be used to estimate morbidity were employed to quantify morbidity at various infection stages. Morbidity was quantified as a direct proportion of the population and the respective national schistosomiasis prevalence. Findings showed that both S. mansoni and S. haematobium are present in Malawi with the latter highly prevalent (50%). Furthermore, out of the estimated population of 16,829 million, approximately 8.4 million have schistosomiasis, with about 4.4 million of these aged 18 years and below. The most frequent manifestation is Katayama syndrome, while ascites is the lowest, impacting about 3.0 million and 960 individuals, respectively. Localised studies on association of schistosomiasis infection to risk factors such as occupation, age and gender found odds ratio (OR) ranging from 1.29 to 5.37. Morbidity due to schistosomiasis is high in Malawi. It is therefore recommended that a more detailed study on the determinants of high schistosomiasis and re-evaluation of the current control measures be conducted if the current morbidity statistics are to be remarkably reduced.