The global burden of disease study 2010: interpretation and implications for the neglected tropical diseases

Colonic schistosomiasis mimicking cancer, polyp, and inflammatory bowel disease: Five case reports and review of literature

BACKGROUND

Schistosomiasis, officially named as a neglected tropical disease by The World Health Organization, is a serious parasitic disease caused by trematode flukes of the genus Schistosoma. It is a common infectious disease, endemic in more than 78 countries. The disease can involve various organs and poses far-reaching public health challenges.

CASE SUMMARY

Here, we present a series of five patients with variable presentations: an asymptomatic patient who was diagnosed with colonic schistosomiasis upon screening colonoscopy; 2 patients with clinical suspicion of colonic cancer; and 2 patients with a clinical diagnosis of inflammatory bowel disease. All patients were subsequently confirmed to have colonic schistosomiasis after colonoscopy and histopathologic examination. The clinical manifestations, colonoscopy features and histologic findings of the patients are described. Most of the patients showed significant clinical improvement following administration of oral praziquantel.

CONCLUSION

Intestinal schistosomiasis can present with features mimicking other gastrointestinal conditions. This disease should be a diagnostic consideration in patients who live in or have traveled to endemic areas.

Evaluation of the Leishmania Inositol Phosphorylceramide Synthase as a Drug Target Using a Chemical and Genetic Approach

The lack of effective vaccines and the development of resistance to the current treatments highlight the urgent need for new anti-leishmanials. Sphingolipid metabolism has been proposed as a promising source of Leishmania-specific targets as these lipids are key structural components of the eukaryotic plasma membrane and are involved in distinct cellular events. Inositol phosphorylceramide (IPC) is the primary sphingolipid in the Leishmania species and is the product of a reaction mediated by IPC synthase (IPCS). The antihistamine clemastine fumarate has been identified as an inhibitor of IPCS in L. major and a potent anti-leishmanial in vivo. Here we sought to further examine the target of this compound in the more tractable species L. mexicana, using an approach combining genomic, proteomic, metabolomic and lipidomic technologies, with molecular and biochemical studies. While the data demonstrated that the response to clemastine fumarate was largely conserved, unexpected disturbances beyond sphingolipid metabolism were identified. Furthermore, while deletion of the gene encoding LmxIPCS had little impact in vitro, it did influence clemastine fumarate efficacy and, importantly, in vivo pathogenicity. Together, these data demonstrate that clemastine does inhibit LmxIPCS and cause associated metabolic disturbances, but its primary target may lie elsewhere.

The psychosocial impacts of skin-neglected tropical diseases (SNTDs) as perceived by the affected persons: A systematic review

BACKGROUND

Neglected Tropical Diseases (NTDs) disproportionately affect marginalised groups within impoverished communities, conferring devastating physical, financial and psychosocial effects. Skin-NTDs (SNTDs) are uniquely stigmatising due to their visible nature, rendering affected individuals vulnerable to psychosocial risk and the associated decline in social participation, quality of life and mental health. In response to knowledge gaps identified by current global efforts for integrated control of SNTDs this review gathers existing evidence on the psychosocial effects of SNTDs, with consideration given to the influence of gender.

METHODS

The study protocol is registered with PROSPERO (CRD42022336676). Data was collected from Embase, Global Health, Medline and Web of Science, with additional articles identified through Google Scholar and bibliography tracking. Qualitative studies published in English between 2005 and 2024 reporting men's and women's experiences with SNTDs were searched. Appropriate data from each included study were inputted into NVivo software to facilitate thematic synthesis. Descriptive and analytic themes were generated through line-by-line coding using an inductive approach.

RESULTS

27 articles of high and moderate quality were included. They pertained to buruli ulcer, cutaneous leishmaniasis, leprosy, lymphatic filariasis, tungiasis, onchocerciasis, schistosomiasis and podoconiosis. Men and women across SNTDs and contexts reported debilitating physical symptoms which impaired their ability to work, socialise and carry out usual daily activities. Some felt (at least initially) well supported by partners and relatives, whereas most experienced avoidance, abandonment and even violence, with women incurring worse SNTD-related social consequences. Many men and most women experienced stigma, with discriminatory behaviours largely attributed to fear of infection, decreased ability to perform gender-specific daily activities, and the perceived association between SNTDs and sinfulness. Self-reported impacts of SNTDs on men's and women's mental wellbeing included low mood, anxiety, low self-esteem, and suicidal ideation. Disease-specific knowledge, early treatment, social support, and disease acceptance were mentioned as protective factors.

CONCLUSION

SNTDs cause significant psychosocial harms, particularly for women. Implementing myth-busting and contact-based educational campaigns and improving access to treatment and to livelihood opportunities and social protection schemes for men and women with a SNTD will help prevent and mitigate these.

Gut microbiota metabolically mediate intestinal helminth infection in Zebrafish

Intestinal helminth parasite (IHP) infection induces alterations in the composition of microbial communities across vertebrates, although how gut microbiota may facilitate or hinder parasite infection remains poorly defined. In this work we utilized a zebrafish model to investigate the relationship between gut microbiota, gut metabolites, and IHP infection. We found that extreme disparity in zebrafish parasite infection burden is linked to the composition of the gut microbiome, and that changes in the gut microbiome are associated with variation in a class of endogenously-produced signaling compounds, N-acylethanolamines, that are known to be involved in parasite infection. Using a statistical mediation analysis, we uncovered a set of gut microbes whose relative abundance explains the association between gut metabolites and infection outcomes. Experimental investigation of one of the compounds in this analysis reveals salicylaldehyde, which is putatively produced by the gut microbe Pelomonas, as a potent anthelmintic with activity against Pseudocapillaria tomentosa egg hatching, both in vitro and in vivo. Collectively, our findings underscore the importance of the gut microbiome as a mediating agent in parasitic infection and highlights specific gut metabolites as tools for the advancement of novel therapeutic interventions against IHP infection.

Availability and readiness of health facilities providing services for other infectious diseases to treat neglected tropical diseases in Ethiopia: implications for service integration in high burden areas

BACKGROUND

The burden of neglected tropical diseases (NTDs), HIV/AIDS, tuberculosis, and malaria pose significant public health challenges in Ethiopia. This study aimed to the explore service availability and readiness for NTD care among Ethiopian health facilities treating tuberculosis (TB), HIV/AIDS, and/or malaria.

METHODS

This study utilized secondary data from the Ethiopian Service Provision Assessment 2021-22 survey. The availability of services was calculated as the percentage of HIV/AIDS, tuberculosis, or malaria facilities providing NTD services. Facilities were considered highly prepared to manage any type of NTD if they scored at least half (> 50%) of the tracer items listed in each of the three domains (staff training and guidelines, equipment, and essential medicines). Descriptive statistics and logistic regression models were employed to present the study findings and analyze factors influencing facility readiness, respectively.

RESULTS

Out of 403 health facilities providing NTD care nationally, 179, 183, and 197 also offer TB, HIV/AIDS, and malaria services, respectively. The majority of TB (90.1%), HIV/AIDS (89.6%), and malaria (90.9%) facilities offer soil-transmitted helminth services, followed by trachoma (range 87-90%). The percentages of the aforementioned facilities with at least one trained staff member for any type of NTD were 87.2%, 88.4%, and 82.1%, respectively. The percentage of facilities with guidelines for any type of NTD was relatively low (range 3.7-4.1%). Mebendazole was the most widely available essential medicine, ranging from 69 to 70%. The overall readiness analysis indicated that none of the included facilities (TB = 11.9%; HIV/AIDS = 11.6%; and malaria = 10.6%) were ready to offer NTD care. Specifically, a higher level of readiness was observed only in the domain of medicines across these facilities. Hospitals had better readiness to offer NTD care than did health centers and clinics. Furthermore, a significant associations were observed between facility readiness and factors such as facility type, region, presence of routine management meetings, types of NTD services provided, and fixed costs for services.

CONCLUSIONS

Ethiopian health facilities treating TB, HIV/AIDS, and malaria had an unsatisfactory overall service availability and a lack of readiness to provide NTD care. Given the existing epidemiological risks and high burden of TB, HIV/AIDS, malaria, and NTDs in Ethiopia, there is an urgent need to consider preparing and implementing a collaborative infectious disease care plan to integrate NTD services in these facilities.

Predicting Schistosomiasis Intensity in Africa: A Machine Learning Approach to Evaluate the Progress of WHO Roadmap 2030

The World Health Organization (WHO) 2030 Roadmap aims to eliminate schistosomiasis as a public health issue, targeting reductions in the heavy intensity of infections. Previous studies, however, have predominantly used prevalence as the primary indicator of schistosomiasis. We introduce several machine learning (ML) algorithms to predict infection intensity categories, using morbidity prevalence, with the aim of assessing the elimination of schistosomiasis in Africa, as outlined by the WHO. We obtained morbidity prevalence and infection intensity data from the Expanded Special Project to Eliminate Neglected Tropical Diseases, which spans 12 countries in sub-Saharan Africa. We then used a series of ML algorithms to predict the prevalence of infection intensity categories for Schistosoma haematobium and Schistosoma mansoni, with morbidity prevalence and several relevant environmental and demographic covariates from remote-sensing sources. The optimal model had high accuracy and stability; it achieved a mean absolute error (MAE) of 0.02, a root mean square error (RMSE) of 0.05, and a coefficient of determination (R2) of 0.84 in predicting heavy-intensity prevalence for S. mansoni; and an MAE of 0.02, an RMSE of 0.04, and an R2 value of 0.81 for S. haematobium. Based on this optimal model, we found that most areas in the surveyed countries have not achieved the target of the WHO road map for 2030. The ML algorithms used in our analysis showed a high overall predictive power in estimating infection intensity for each species, and our methods provided a low-cost, effective approach to evaluating the disease target in Africa set in the WHO road map for 2030.

Cost-effectiveness of sentinel screening of endemic diseases alongside malaria diagnosis: A case study in schistosomiasis

BACKGROUND

In countries where malaria is endemic, the use of rapid diagnostic tests(RDTs) has become routine, especially in rural settings. Such regions are characterised by often having other co-endemic infectious diseases, at high levels of prevalence.

AIM

To illustrate the potential added-value of "sentinel" screening for patients presenting for a routine diagnostic test for malaria, at healthcare facilities in Uganda.

METHODS

We developed an economic model by combining two decision trees, one for malaria and a second for the co-endemic disease schistosomiasis. The integrated model was designed to inform policy strategies for the co-endemic disease in addition to malaria (i.e., whether to test opportunistically for schistosomiasis or use mass drug administration(MDA) as per usual practice).We performed the analysis on three comparators varying testing accuracy and costs.

RESULTS

Sentinel screening can provide added value to the testing of patients compared with the status quo: when schistosomiasis prevalence is high then MDA is preferential; if low prevalence, treating no one is preferred. If the disease has average levels of prevalence, then a strategy involving testing is preferred. Prevalence thresholds driving the dominant strategy are dependent upon the model parameters, which are highly context specific. At average levels of prevalence for schistosomiasis and malaria for Uganda, adding a sentinel screening was cost-effective when the accuracy of test was higher than current diagnostics and when economies of scope were generated(Expected value clinical Information = 0.65$ per DALY averted, 137.91$ per correct diagnoses).Protocols using diagnostics with current accuracy levels were preferred only for levels of MDA coverage below 75%.

CONCLUSION

The importance of the epidemiological setting is crucial in determining the best cost-effective strategy for detecting endemic disease. Economies of scope can make sentinel screenings cost-effective strategies in specific contexts. Blanket thresholds recommended for MDA may not always be the preferred option for endemic diseases.

RNA-seq gene expression profiling of the bladder in a mouse model of urogenital schistosomiasis

Background

Parasitic flatworms of the Schistosoma genus cause schistosomiasis, which affects over 230 million people. Schistosoma haematobium causes the urogenital form of schistosomiasis (UGS), which can lead to hematuria, fibrosis, and increased risk of secondary infections by bacteria or viruses. UGS is also linked to bladder cancer. To understand the bladder pathology during S. haematobium infection, our group previously developed a mouse model that involves the injection of S. haematobium eggs into the bladder wall. Using this model, we studied changes in epigenetics profile, as well as changes in gene and protein expression in the host bladder tissues. In the current study, we expand upon this work by examining the expression level of both host and parasite genes using RNA sequencing (RNA-seq) in the mouse bladder wall injection model of S. haematobium infection.

Methods

We used a mouse model of S. haematobium infection in which parasite eggs or vehicle control were injected into the bladder walls of female BALB/c mice. RNA-seq was performed on the RNA isolated from the bladders four days after bladder wall injection.

Results/Conclusions

RNA-seq analysis of egg- and vehicle control-injected bladders revealed the differential expression of 1025 mouse genes in the egg-injected bladders, including genes associated with cellular infiltration, immune cell chemotaxis, cytokine signaling, and inflammation We also observed the upregulation of immune checkpoint-related genes, which suggests that while the infection causes an inflammatory response, it also dampens the response to avoid excessive inflammation-related damage to the host. Identifying these changes in host signaling and immune responses improves our understanding of the infection and how it may contribute to the development of bladder cancer. Analysis of the differential gene expression of the parasite eggs between bladder-injected versus uninjected eggs revealed 119 S. haematobium genes associated with transcription, intracellular signaling, and metabolism. The analysis of the parasite genes also revealed fewer transcript reads compared to that found in the analysis of mouse genes, highlighting the challenges of studying parasite egg biology in the mouse model of S. haematobium infection.

Th2-biased immune responses to body migrating Ascaris larvae in primary infection are associated with pathology but not protection

Helminth infections lead to an overdispersion of the parasites in humans as well as in animals. We asked whether early immune responses against migrating Ascaris larvae are responsible for the unequal distribution of worms in natural host populations and thus investigated a susceptible versus a resistant mouse strain. In mice, the roundworm larvae develop until the lung stage and thus early anti-Ascaris immune responses against the migrating larvae in the liver and lung can be deciphered. Our data show that susceptible C57BL/6 mice respond to Ascaris larval migration significantly stronger compared to resistant CBA mice and the anti-parasite reactivity is associated with pathology. Increased eosinophil recruitment was detected in the liver and lungs, but also in the spleen and peritoneal cavity of susceptible mice on day 8 post infection compared to resistant mice. In serum, eosinophil peroxidase levels were significantly higher only in the susceptible mice, indicating functional activity of the recruited eosinophils. This effect was associated with an increased IL-5/IL-13 production by innate lymphoid cells and CD4+ T cells and a pronounced type 2 macrophage polarization in the lungs of susceptible mice. Furthermore, a comparison of wildtype BALB/c and eosinophil-deficient dblGATA-1 BALB/c mice showed that eosinophils were not essential for the early control of migrating Ascaris larvae. In conclusion, in primary infection, a strong local and systemic type 2 immune response during hepato-tracheal helminth larval migration is associated with pathology rather than protection.

Visceral leishmaniasis follow-up and treatment outcomes in Tiaty East and West sub-counties, Kenya: Cure, relapse, and Post Kala-azar Dermal Leishmaniasis

BACKGROUND

Visceral Leishmaniasis (VL) is a neglected tropical disease (NTD) with the highest regional burden in East Africa. Relapse and Post Kala-azar Dermal Leishmaniasis (PKDL) contribute to the spread of VL in endemic areas, making their surveillance imperative for control and elimination. Little is known about long-term patient outcomes in Kenya through follow-up after VL treatment, despite its requirement for control and elimination by the World Health Organization (WHO) and the Kenya Ministry of Health (KMOH).

METHODOLOGY/PRINCIPAL FINDINGS

36 follow-up patients in Tiaty East and West, sub-counties, Kenya, and records from 248 patients at the regional Chemolingot Sub-county Hospital (CSCH) were analyzed separately using Fisher's Exact Tests, two-sample t-tests, and Welch's t-tests in R (Version 4.3.0). The study found a prevalence rate of 88.89% (n = 32) final cure, 5.56% (n = 2) relapse, and 5.56% (n = 2) PKDL in follow-up patients and 92.74% (n = 230) initial cure, 6.86% (n = 17) relapse, and 0.80% (n = 2) PKDL in overall CSCH patients. The mean lengths of time at which follow-up patients relapsed and developed PKDL were 4.5 and 17 months, respectively. Young age (p = 0.04, 95% CI 0.63-24.31), shorter length of time from initial treatment to follow-up (p = 0.002, 95% CI 1.03-∞), lower Hb level at primary treatment (p = 0.0002, 95% CI 1.23-3.24), and living in Tiaty East sub-county (p = 0.04, 95% CI 0.00-1.43) were significantly associated (p<0.05) with VL relapse in follow-up study patients. Female sex (p = 0.04, 95% CI 0.84-∞) and living in Tiaty East sub-county (p = 0.03, 95% CI 0.00-1.43) were significantly associated with PKDL in follow-up study patients.

CONCLUSIONS/SIGNIFICANCE

More research should be done on PKDL in Kenya with active follow-up to understand its true burden. These results on prevalence and risk factors for PKDL and relapse in Kenya should inform knowledge of patient outcomes and interventions in the region.

Human Placental Schistosomiasis-A Systematic Review of the Literature

BACKGROUND

Schistosome egg deposition in pregnant women may affect the placenta of infected mothers and cause placental schistosomiasis (PS). Histopathological examination of placental tissue is an inadequate detection method due to low sensitivity. So far, there has not been any systematic review on PS.

METHODS

We conducted a systematic literature search on PubMed, EMBASE, and Medline and included all publications that reported microscopically confirmed cases of PS, as well as the relevant secondary literature found in the citations of the primarily included publications.

RESULTS

Out of 113 abstracts screened we found a total of 8 publications describing PS with a total of 92 cases describing egg deposition of dead and/or viable eggs and worms of S. haematobium and S. mansoni in placental tissue. One cross-sectional study investigating the prevalence of PS and its association with adverse birth outcomes, found 22% of placentas to be infested using a maceration technique but only <1% using histologic examination. Additionally, no direct link to deleterious pregnancy outcomes could be shown.

CONCLUSIONS

PS is a highly unattended and underdiagnosed condition in endemic populations, due to a lack of awareness as well as low sensitivity of histopathological examinations. However, PS may play an important role in mediating or reinforcing adverse birth outcomes (ABO) such as fetal growth restriction (FGR) in maternal schistosomiasis, possibly by placental inflammation.

Rapid appraisal of liver diseases using transient elastography, abdominal ultrasound, and microbiology in Côte d'Ivoire: A single-center study

BACKGROUND

Liver diseases of infectious and non-infectious etiology cause considerable morbidity and mortality, particularly in low- and middle-income countries (LMICs). However, data on the prevalence of liver diseases and underlying risk factors in LMICs are scarce. The objective of this study was to elucidate the occurrence of infectious diseases among individuals with chronic liver damage in a rural setting of Côte d'Ivoire.

METHODOLOGY

In 2021, we screened 696 individuals from four villages in the southern part of Côte d'Ivoire for hepatic fibrosis and steatosis, employing transient elastography (TE) and controlled attenuation parameter (CAP). We classified CAP ≥248 dB/m as steatosis, TE ≥7.2 kPa as fibrosis, and did subgroup analysis for participants with TE ranging from 7.2 kPa to 9.1 kPa. Clinical and microbiologic characteristics were compared to an age- and sex-matched control group (TE <6.0 kPa; n = 109). Stool samples were subjected to duplicate Kato-Katz thick smears for diagnosis of Schistosoma mansoni. Venous blood samples were examined for hepatitis B and hepatitis C virus. Additionally, an abdominal ultrasound examination was performed.

PRINCIPAL FINDINGS

Among 684 individuals with valid TE measurements, TE screening identified hepatic pathologies in 149 participants (17% with fibrosis and 6% with steatosis). 419 participants were included for further analyses, of which 261 had complete microbiologic analyses available. The prevalence of S. mansoni, hepatitis B, and hepatitis C were 30%, 14%, and 7%, respectively. Logistic regression analysis revealed higher odds for having TE results between 7.2 kPa and 9.1 kPa in individuals with S. mansoni infection (odds ratio [OR] = 3.02, 95% confidence interval [CI] = 1.58-5.76, P = 0.001), while HCV infection (OR = 5.02, 95% CI = 1.72-14.69, P = 0.003) and steatosis (OR = 4.62, 95% CI = 1.60-13.35, P = 0.005) were found to be risk factors for TE ≥9.2 kPa.

CONCLUSIONS/SIGNIFICANCE

Besides viral hepatitis, S. mansoni also warrants consideration as a pathogen causing liver fibrosis in Côte d'Ivoire. In-depth diagnostic work-up among individuals with abnormal TE findings might be a cost-effective public health strategy.

Community preferred drug delivery approaches for pilot roll-out of a potential novel paediatric schistosomiasis treatment option in two endemic counties of Kenya: A mixed methods study

Treating preschool age children (PSAC) for schistosomiasis has remained a challenge due to lack of a pediatric formulation. In response to this unmet need, the Paediatric Praziquantel Consortium has developed a potential novel paediatric treatment option. In advance to its roll-out to follow regulatory response, we conducted a social science study to gather information on preferred drug delivery approaches to inform implementation. A cross-sectional study was conducted in eight villages in two purposively selected Kenyan counties. A questionnaire was administered on 690 parents/guardians of PSAC at household level. Preferred drug delivery approaches were analyzed using frequencies and proportions. We conducted key informant interviews with 17 opinion leaders and 28 healthcare workers, and 12 focus group discussions with parents/guardians of PSAC and 7 with community health volunteers (CHVs). Thematic analysis was performed on the qualitative data. Majority of the 690 respondents were women 594 (86.1%) with a mean age of 34.1 (SD = 11.3, min-max = 18-86). Community-based mass drug administration (cMDA) was the most preferred drug delivery method by 598 participants (86.7%), followed by health facility/fixed points by 398 participants (57.7%). Similarly, in the qualitative data participants indicated they prefer cMDA since the CHVs who would distribute the medication are familiar with households with PSAC and are trusted to explain the drug effects. Health facilities/fixed points were the second most preferred drug delivery approach, but some health workers we interviewed expressed concern about potential understaffing and overcrowding of facilities. Appropriate timing of the drug distribution, not to interfere with farming activities, was considered critical, irrespective of the approach used. All profiles of study participants preferred cMDA over the other delivery approaches due to the convenience of receiving drugs at home and providing explanations about the new drug. For positive outcomes, adequate planning, proper timings and community involvement are highly recommended.

CYP2C19 and CYP2J2 genotypes predict praziquantel plasma exposure among Ethiopian school-aged children

Metabolism of praziquantel (PZQ), a racemic mixture and the only drug approved to treat S. mansoni infection, is mediated by genetically polymorphic enzymes. Periodic school-based mass drug administration (MDA) with PZQ is the core intervention to control schistosomiasis. However data on the impact of pharmacogenetic variation, nutrition, and infection status on plasma PZQ exposure is scarce. We investigated genetic and non-genetic factors influencing PZQ plasma concentration and its metabolic ratios (trans-4-OH-PZQ/PZQ and cis-4-OH-PZQ/PZQ). Four hundred forty-six school children aged 7-15 years from four primary schools in southern Ethiopia who received albendazole and PZQ preventive chemotherapy through MDA campaign were enrolled. Genotyping for common functional variants of CYP3A4 (*1B), CYP3A5 (*3, *6), CYP2C19 (*2, *3, *17), CYP2C9 (*2, *3), and CYP2J2*7 was performed. Plasma concentrations of PZQ, trans-4-OH-PZQ, and cis-4-OH-PZQ were quantified using UPLCMS/MS. Carriers of CYP2C19 defective variant alleles (*2 and *3) had significantly higher mean PZQ plasma concentration than CYP2C19*1/*1 or *17 carriers (p = 0.005). CYP2C19*1/*1 and CYP2C19*17 carriers had higher trans-4-OH-PZQ/PZQ and cis-4-OH-PZQ/PZQ metabolic ratios compared with CYP2C19*2 or *3 carriers (p < 0.001). CYP2J2*7 carriers had lower mean PZQ plasma concentration (p = 0.05) and higher trans-4-OH-PZQ/PZQ and cis-4-OH-PZQ/PZQ metabolic ratios. Male participants had significantly higher PZQ concentration (p = 0.006) and lower metabolic ratios (p = 0.001) than females. There was no significant effect of stunting, wasting, S. mansoni or soil-transmitted helminth infections, CYP3A4, CYP3A5, or CYP2C9 genotypes on plasma PZQ or its metabolic ratios. In conclusion, sex, CYP2C19 and CYP2J2 genotypes significantly predict PZQ plasma exposure among Ethiopian children. The impact of CYP2C19 and CYP2J2 genotypes on praziquantel treatment outcomes requires further investigation.

Dual Strategy to Design New Agents Targeting Schistosoma mansoni: Advancing Phenotypic and SmCB1 Inhibitors for Improved Efficacy

In this study, we have identified and optimized two lead structures from an in-house screening, with promising results against the parasitic flatworm Schistosoma mansoni and its target protease S. mansoni cathepsin B1 (SmCB1). Our correlation analysis highlighted the significance of physicochemical properties for the compounds' in vitro activities, resulting in a dual approach to optimize the lead structures, regarding both phenotypic effects in S. mansoni newly transformed schistosomula (NTS), adult worms, and SmCB1 inhibition. The optimized compounds from both approaches ("phenotypic" vs "SmCB1" approach) demonstrated improved efficacy against S. mansoni NTS and adult worms, with 2h from the "SmCB1" approach emerging as the most potent compound. 2h displayed nanomolar inhibition of SmCB1 (Ki = 0.050 μM) while maintaining selectivity toward human off-target cathepsins. Additionally, the greatly improved efficacy of compound 2h toward S. mansoni adults (86% dead worms at 10 μM, 68% at 1 μM, 35% at 0.1 μM) demonstrates its potential as a new therapeutic agent for schistosomiasis, underlined by its improved permeability.

Contribution of parasite and host genotype to immunopathology of schistosome infections

BACKGROUND

The role of pathogen genotype in determining disease severity and immunopathology has been studied intensively in microbial pathogens including bacteria, fungi, protozoa and viruses but is poorly understood in parasitic helminths. The medically important blood fluke Schistosoma mansoni is an excellent model system to study the impact of helminth genetic variation on immunopathology. Our laboratory has demonstrated that laboratory schistosome populations differ in sporocyst growth and cercarial production in the intermediate snail host and worm establishment and fecundity in the vertebrate host. Here, we (i) investigate the hypothesis that schistosome genotype plays a significant role in immunopathology and related parasite life history traits in the vertebrate mouse host and (ii) quantify the relative impact of parasite and host genetics on infection outcomes.

METHODS

We infected BALB/c and C57BL/6 mice with four different laboratory schistosome populations from Africa and the Americas. We quantified disease progression in the vertebrate host by measuring body weight and complete blood count (CBC) with differential over a 12-week infection period. On sacrifice, we assessed parasitological (egg and worm counts, fecundity), immunopathological (organ measurements and histopathology) and immunological (CBC with differential and cytokine profiles) characteristics to determine the impact of parasite and host genetics.

RESULTS

We found significant variation between parasite populations in worm numbers, fecundity, liver and intestine egg counts, liver and spleen weight, and fibrotic area but not in granuloma size. Variation in organ weight was explained by egg burden and intrinsic parasite factors independent of egg burden. We found significant variation between infected mouse lines in cytokine levels (IFN-γ, TNF-α), eosinophils, lymphocytes and monocyte counts.

CONCLUSIONS

This study showed that both parasite and host genotype impact the outcome of infection. While host genotype explains most of the variation in immunological traits, parasite genotype explains most of the variation in parasitological traits, and both host and parasite genotypes impact immunopathology outcomes.

The impact of health on economic growth: A narrative literature review

The nexus between health and economic growth is a dynamic and complex relationship. This article reviews the empirical evidence that has sought to assess the causal impact of health on growth, understood as growth in GDP per capita, and focusing on cross-country and selected single country studies. The review largely provides evidence in favour of a positive effect of population health on economic growth. However, the multitude of the factors at play and the possible bidirectional relationship between health and growth pose a challenge for the quantification of the effect and for the relative importance of the underlying mechanisms. There is notable heterogeneity between studies in the magnitude and, in some cases, even in the sign of the effect. The evidence suggests that the health-growth relationship may depend on three main factors: the sample composition (i.e. a country's demographic stage or GDP per capita); the health dimension considered (e.g. health improvements at different life stages may affect productivity differently); and the model specification (e.g. whether or not initial life expectancy is controlled for in the analysis or the quality of the instrument). These findings advocate for a policy approach that integrates health considerations into economic strategies and emphasizes intersectoral collaboration to maximize the economic returns from improved health outcomes.

A 14-year review (2007-2020) of helminthiasis epidemiology in a hospital in Southern Madrid, Spain

PURPOSE

Vast majority of helminth diseases remain neglected tropical diseases (NTDs), causing significant morbidity. The widespread and periodic distribution of antiparasitic drugs, remains the cornerstone for controlling these diseases. In Spain, most helminthiasis cases are imported, and suspicion and diagnosis have become increasingly important. Our primary objective is to present the epidemiological landscape of helminthiasis diagnoses within our facility, while also detailing the demographic characteristics of the affected population.

METHODS

A retrospective study was conducted at the Hospital Universitario Severo Ochoa (HUSO) from January 1, 2007, to December 31, 2020, encompassing all diagnosed cases of helminthiasis during this period. Comprehensive epidemiological, clinical, and microbiological data were gathered for all diagnosed patients. The study population comprised patients receiving treatment at the HUSO, as well as those receiving treatment at the Leganés and Fuenlabrada Primary Care Units. Subsequently, descriptive and comparative statistics were performed, comparing Spanish and foreign patients.

RESULTS

During this period, a total of 952 patients were diagnosed with some form of helminthiasis. Among them, 495 were Spanish, and 457 were foreign. The total number of helminths identified, including patients with multiple infections, was 1,010. Significant differences were observed between Africans and Americans in terms of age distribution, with a higher prevalence among Africans in the 0-15 age range and among Americans in the 31-60 age range. Variations were noted in the distribution of helminths, with S. stercoralis significantly affecting Americans. For Spanish patients, the presence of Trichuris trichiura and S. stercoralis was significantly associated with eosinophilia, whereas among foreign patients, it was associated with Trichuris trichiura, Ascaris lumbricoides among others. Regarding symptoms, skin manifestations were more frequent among Spanish, while digestive were more common among foreigners.

CONCLUSIONS

This study offers crucial epidemiological insights into helminth infections observed over time in a Madrid hospital. Although the prevalence of helminth infections has been decreasing, there is still a need for screening and diagnosing foreign patients.

Parasitic contamination of fresh vegetables and fruits sold in open-air markets in peri-urban areas of Jimma City, Oromia, Ethiopia: A community-based cross-sectional study

BACKGROUND

Consuming contaminated raw vegetables and fruits is one of the primary means of parasite transmission to humans. Periodic monitoring of parasitic contamination in these food items is a crucial step in preventing the spread of parasitic disease in the community. This study was aimed at detecting intestinal parasitic contamination caused by consuming raw vegetables and fruits sold in three open-air markets and its associated factors in peri-urban areas of Jimma City, Oromia, Ethiopia.

METHODS

A cross-sectional study was conducted on fruits and vegetables collected from three peri-urban open-aired markets (namely; Hora Gibe, Bore and Jiren markets) in peri-urban areas of Jimma City between July and September 2021. A total of 187 fresh vegetable samples and 188 fruits were collected and examined for intestinal parasite contamination. About 200g of fruit and vegetable samples were processed and examined microscopically for parasite contamination, utilizing direct wet mount and modified Zeihl-Neelson staining methods in accordance with standard protocols. A structured questionnaire was used to collect data on the socio-demographic characteristics of vendors and risk factors for fruit and vegetable contamination. All data were analyzed using SPSS version 20.0.

RESULT

Of the 187 fresh vegetable samples and 188 fresh vegetable samples, 105 (56.1%) and 68/188 (36.2%) of vegetables and fruit samples, respectively, were found contaminated with one or more intestinal parasites. Remarkably, high level of contamination in fresh vegetable samples was recorded both in Carrot (Daucus carota) 63.8% (30/46) and Lettuce (Lactuca sativa) 63.1% (29/46) while Green pepper (Capsicum spp.) is the least contaminated. In fruit samples, Avokado (Persea americana) 42.6% (20/47) and Banana (Musa acuminata) 14.9% (7/47) were the most and the least commonly contaminated items respectively. The identified helminthes and protozoans were Ascaris lumbricoides, Strongyloides stercoralis, Hymenolepis nana, Entamoeba histolytica/dispar, Giardia lamblia, Cryptosporidium spp., Toxocara spp. And Fasciola spp. The most predominant parasite encountered was A. lumbricoides 46(12.3%) whereas both Toxocara spp. 12(6.9) and Fasciola spp. 2(0.5) were the least detected parasites. It is worth-mentioned that the rate of contamination in Bore market (38.15%) was higher compared with Jiren market (34.7%) and Hora Gibe market (27%). However, the rate of contamination in vegetables and fruit obtained from the three district was non-significant (p = 0.19). Contamination was more common in vegetables than fruits (AOR = 5.78, p<0.001). It was also observed that decreased parasitic contamination was significantly associated with washing the products before displaying it for selling (p < 0.001).

CONCLUSION

The study has identified a high rate of raw vegetables and fruits contaminated with intestinal helminthes and protozoan. Contaminated fresh vegetables and fruits in open-aired peri-urban markets of Jimma city, Ethiopia may play a significant role in transmission of intestinal parasitic infections to humans, particularly A. lumbricoides infection. Therefore, it is urgently needed for health authorities to educate the public on the proper handling of vegetables and fruits prior to consumption.

Status of selected biochemical and coagulation profiles and platelet count in malaria and malaria-Schistosoma mansoni co-infection among patients attending at Dembiya selected Health Institutions, Northwest Ethiopia

Malaria and schistosomiasis are infectious diseases that cause coagulation disorders, biochemical abnormalities, and thrombocytopenia. Malaria and Schistosoma mansoni co-infection cause exacerbations of health consequences and co-morbidities.This study aimed to compare the effect of malaria and Schistosoma mansoni co-infection and malaria infection on selected biochemical and coagulation profiles, and platelet count. An institutional-based comparative cross-sectional study was conducted from March 30 to August 10, 2022. A total of 70 individuals were enrolled in the study using a convenient sampling technique. Wet mount and Kato Katz techniques were conducted to detect Schistosoma mansoni in a stool sample. Blood films were prepared for the detection of plasmodium. The data was coded and entered into EpiData version 3.1 before being analyzed with SPSS version 25. An independent t test was used during data analysis. A P-value of less than 0.05 was considered statistically significant. The mean [SD] of alanine aminotransferase, aspartate aminotransferase, creatinine, total bilirubin, and direct bilirubin in the co-infected was higher than in malaria infected participants. However, the mean of total protein and glucose in co-infected was lower than in the malaria infected participants. The mean of prothrombin time, international normalization ratio, and activated partial thromboplastin time in co-infected was significantly higher, while the platelet count was lower compared to malaria infected participants. Biochemical and coagulation profiles, and platelet count status in co-infection were changed compared to malaria infected participants. Therefore, biochemical and coagulation profiles and platelet count tests should be used to monitor and manage co-infection related complications and to reduce co-infection associated morbidity and mortality.

Mass drug administration for neglected tropical disease control and elimination: a systematic review of ethical reasons

BACKGROUND

Neglected tropical diseases (NTDs) are a diverse group of debilitating diseases and conditions afflicting more than one billion people in impoverished communities. Control of these diseases is crucial to achieve Sustainable Development Goal 3 and the pledge to 'leave no one behind'. Relying on large-scale delivery of wide-spectrum drugs to individuals in at-risk communities irrespective of their health status, mass drug administration is a core strategy for tackling half of the NTDs targeted by the latest WHO roadmap (2021-2030). However, ethical challenges surround its implementation and long-term impact. This systematic review aims to give a comprehensive picture of the variety of ethical reasons for and against mass drug administration for NTD control and elimination, facilitating further debate in ethics and policy.

METHODS

PubMed and Web of Science Core Collection were searched for all relevant publications. Of the 486 retrieved records, 60 met the inclusion criteria for qualitative analysis. Ethical reasons discussing the topic at hand were extracted from full texts and synthesised through the Kuckartz method of qualitative content analysis.

RESULTS

Data extraction revealed 61 ethical reasons, of which 20 (32.7%) had positive, 13 (21.3%) had ambivalent and 28 (45.9%) had negative implications regarding mass drug administration for NTDs. The health benefits and cost-effectiveness of the measure were extensively highlighted. However, equity, autonomy and sustainability emerged as the domains with the most pressing ethical concerns. Many issues related to implementation are yet to be adequately addressed in policy documents.

CONCLUSIONS

This is the first systematic review of ethical reasons pertaining to mass drug administration for NTD control and elimination. Due to the diversity of included studies, no general recommendations can be made. Instead, context-specific strategies seem necessary. Alternative approaches tackling socioecological determinants of ill health are needed for long-term sustainability. Future research could benefit from contributions of non-Western philosophies and perspectives by local researchers.

The egg ribonuclease SjCP1412 accelerates liver fibrosis caused by Schistosoma japonicum infection involving damage-associated molecular patterns (DAMPs)

Schistosomiasis, a parasite infectious disease caused by Schistosoma japonicum, often leads to egg granuloma and fibrosis due to the inflammatory reaction triggered by egg antigens released in the host liver. This study focuses on the role of the egg antigens CP1412 protein of S. japonicum (SjCP1412) with RNase activity in promoting liver fibrosis. In this study, the recombinant egg ribonuclease SjCP1412, which had RNase activity, was successfully prepared. By analysing the serum of the population, it has been proven that the anti-SjCP1412 IgG in the serum of patients with advanced schistosomiasis was moderately correlated with liver fibrosis, and SjCP1412 may be an important antigen associated with liver fibrosis in schistosomiasis. In vitro, the rSjCP1412 protein induced the human liver cancer cell line Hep G2 and liver sinusoidal endothelial cells apoptosis and necrosis and the release of proinflammatory damage-associated molecular patterns (DAMPs). In mice infected with schistosomes, rSjCP1412 immunization or antibody neutralization of SjCP1412 activity significantly reduced cell apoptosis and necroptosis in liver tissue, thereby reducing inflammation and liver fibrosis. In summary, the SjCP1412 protein plays a crucial role in promoting liver fibrosis during schistosomiasis through mediating the liver cells apoptosis and necroptosis to release DAMPs inducing an inflammatory reaction. Blocking SjCP1412 activity could inhibit its proapoptotic and necrotic effects and alleviate hepatic fibrosis. These findings suggest that SjCP1412 may be served as a promising drug target for managing liver fibrosis in schistosomiasis japonica.

Community's knowledge, perceptions and preventive practices on Onchocerciasis in Jimma zone, Ethiopia, formative mixed study

BACKGROUND

In Ethiopia, Onchocerciasis is a prevalent neglected tropical disease, currently targeted for elimination with mass drug administration and community behavioral changes towards sustained control and eventual elimination. This study aimed to elucidate the awareness, perceptions and practices of endemic communities in Jimma Zone, Ethiopia.

METHODS AND MATERIALS

Community-based cross-sectional study triangulated with qualitative method was conducted from October-November, 2021. A multistage sampling was employed and data were collected using a pre-tested interviewer-administered structured questionnaire. Logistic regression was used to identify the predictors of comprehensive knowledge and preventive practice. Adjusted odds ratios were calculated at 95% confidence interval (CI) and considered significant with a p-value of <0.05. Kruskal-Whallis and Mann-whitney tests were used to compare median risk perception score by socio-demographic factors. Qualitative data were collected through focus group discussions and key informant interviews and transcribed verbatim. Then the data were coded, categorized, and themes were developed.

RESULT

The overall prevalence of adequate comprehensive knowledge was 48.8% (95% CI: 44.9, 52.3), high risk perception was 18.7% (95%CI15.9, 21.4) and preventive practice was 46.9%(95%CI:(43.3,50.4). High risk perception[AOR = 1.95 95%CI: (1.32, 2.89] was statistically significant with comprehensive knowledge, likewise knowledge of mode of transmission [AOR = 2.64 95% CI: (1.44, 4.85)], knowledge of consequences [AOR = 2.12 95%CI: (1.21, 3.72)] and knowledge of preventive measures [AOR = 15.65,95%CI:(10.1, 24.2)] were statistically significant with preventive practice. The median risk perception was varied significantly between the groups by educational status, study district and age category. Qualitative evidence showed that there were great community knowledge gap about the disease.

CONCLUSION

Community knowledge, perceptions, and practices are unacceptably low. Risk perception was significantly associated with comprehensive knowledge, likewise knowledge of mode of transmission, consequences and preventive measures were significantly associated with preventive practice. This implies knowledge is a key component of effective prevention strategies as it is a necessary condition for the behavior change.

A machine learning approach for modeling the occurrence of the major intermediate hosts for schistosomiasis in East Africa

Schistosomiasis, a prevalent water-borne disease second only to malaria, significantly impacts impoverished rural communities, primarily in Sub-Saharan Africa where over 90% of the severely affected population resides. The disease, majorly caused by Schistosoma mansoni and S. haematobium parasites, relies on freshwater snails, specifically Biomphalaria and Bulinus species, as crucial intermediate host (IH) snails. Targeted snail control is advisable, however, there is still limited knowledge about the community structure of the two genera especially in East Africa. Utilizing a machine learning approach, we employed random forest to identify key features influencing the distribution of both IH snails in this region. Our results reveal geography and climate as primary factors for Biomphalaria, while Bulinus occurrence is additionally influenced by soil clay content and nitrogen concentration. Favorable climate conditions indicate a high prevalence of IHs in East Africa, while the intricate connection with geography might signify either dispersal limitations or environmental filtering. Predicted probabilities demonstrate non-linear patterns, with Bulinus being more likely to occur than Biomphalaria in the region. This study provides foundational framework insights for targeted schistosomiasis prevention and control strategies in the region, assisting health workers and policymakers in their efforts.

Visceral Leishmaniasis in Immunocompetent Hosts in Brescia: A Case Series and Analysis of Cytokine Cascade

Visceral leishmaniasis (VL) is a parasitic zoonosis caused by Leishmania spp. that usually manifests itself in immunocompromised subjects. It is a rare and neglected disease, and it is not endemic in the province of Brescia (Italy). Three cases of human VL occurred in Brescia from October to December 2021 in immunocompetent patients. We evaluated the patients looking for signs of underlying immunodeficiencies and conducted further epidemiological evaluations in the province of Brescia without success. An analysis of the sera levels of the main cytokines involved in the immune response to VL was performed. All patients presented a significant augmentation of CXCL-10, CCL-4, and IL-6. The patients tested during the acute phase showed an elevation of IL-1α, IL-5, IL-10, and IL-12, while in the recovery phase, higher levels of TNF-α and IL-7 were detected. Altogether, a predominant activation of the T-helper-2 pathway emerged during the acute phase of the parasite infection, while the cytokines associated with the T-helper-1 pathway were less represented. This imbalanced immune response to the parasite infection might play a crucial role in the development of VL in immunocompetent patients.

Recruitment and Maintenance of CX3CR1+CD4+ T Cells during Helminth Infection

Distinct subsets of T lymphocytes express CX3CR1 under inflammatory conditions, but little is known about CX3CR1+CD4+ T cells during type 2 inflammation in helminth infections. In this study, we used a fate-mapping mouse model to characterize CX3CR1+CD4+ T cells during both acute Nippostrongylus brasiliensis and chronic Schistosoma mansoni murine models of helminth infections, revealing CX3CR1+CD4+ T cells to be an activated tissue-homing subset with varying capacity for cytokine production. Tracking these cells over time revealed that maintenance of CX3CR1 itself along with a TH2 phenotype conferred a survival advantage in the inflamed tissue. Single-cell RNA sequencing analysis of fate-mapped CX3CR1+CD4+ T cells from both the peripheral tissue and the spleen revealed a considerable level of diversity and identified a distinct population of BCL6+TCF-1+PD1+CD4+ T cells in the spleen during helminth infections. Conditional deletion of BCL6 in CX3CR1+ cells resulted in fewer CX3CR1+CD4+ T cells during infection, indicating a role in sustaining CD4+ T cell responses to helminth infections. Overall, our studies revealed the behavior and heterogeneity of CX3CR1+CD4+ T cells during type 2 inflammation in helminth infections and identified BCL6 to be important in their maintenance.

Neglected tropical disease (NTD) diagnostics: current development and operations to advance control

Neglected tropical diseases (NTDs) have become important public health threats that require multi-faceted control interventions. As late treatment and management of NTDs contribute significantly to the associated burdens, early diagnosis becomes an important component for surveillance and planning effective interventions. This review identifies common NTDs and highlights the progress in the development of diagnostics for these NTDs. Leveraging existing technologies to improve NTD diagnosis and improving current operational approaches for deployment of developed diagnostics are crucial to achieving the 2030 NTD elimination target. Point-of-care NTD (POC-NTD) diagnostic tools are recommended preferred diagnostic options in resource-constrained areas for mapping risk zones and monitoring treatment efficacy. However, few are currently available commercially. Technical training of remote health care workers on the use of POC-NTD diagnostics, and training of health workers on the psychosocial consequences of these diagnostics are critical in harnessing POC-NTD diagnostic potential. While the COVID-19 pandemic has challenged the possibility of achieving NTD elimination in 2030 due to the disruption of healthcare services and dwindling financial support for NTDs, the possible contribution of NTDs in exacerbating COVID-19 pandemic should motivate NTD health system strengthening.

Prevalence of helmintic infections in Brazilian Maxakali indigenous: a repeated cross-sectional design

BACKGROUND

The prevalence of intestinal parasites is known to be high among Amerindian populations; further, there are serious problems in the healthcare of these populations in Brazil. The Maxakali, located in the northeastern region of Minas Gerais, Brazil, is an indigenous group that still preserves many of its cultural aspects. This study aimed to compare the positivity rate of schistosomiasis and soil-transmitted helminths in this ethnic group in epidemiological surveys conducted in 1972 and 2014.

METHODS

Stool parasitological examinations were performed by the Kato-Katz technique during both periods in this population. In 2014, the parasitological diagnosis was also realized with the TF-Test® technique.

RESULTS

In 1972, 270 inhabitants were examined. The positivity rates were 67.4% for Schistosoma mansoni, 72.9% for hookworms, 43.7% for Ascaris lumbricoides, and 23.7% for Trichuris trichiura. In 2014, 545 individuals were examined, and the positivity rates obtained were 45.7% for S. mansoni, 22.8% for hookworms, 0.6% for A. lumbricoides, and 2.8% for T. trichiura.

CONCLUSIONS

The comparison of the parasitological surveys conducted in 1972 and 2014, indicates that the indigenous Maxakali remained neglected by the health and indigenous protection authorities during these four decades. The infection rate observed in 2014 for schistosomiasis and hookworm remains high, considering the current epidemiological view of these diseases in the Brazilian population.

Human Trypanosoma cruzi infection in the Argentinean Chaco: risk factors and identification of households with infected children for treatment

BACKGROUND

Chagas disease is a neglected tropical disease (NTD). Cost-effective strategies for large-scale implementation of diagnosis and etiological treatment are urgently needed to comply with NTD control goals. We determined the seroprevalence of Trypanosoma cruzi infection and associated risk factors in a well-defined rural population of Pampa del Indio municipality including creole and indigenous (Qom) households and developed two indices to identify houses harboring infected children.

METHODS

We serodiagnosed and administered a questionnaire to 1337 residents (48.2% of the listed population) in two sections of the municipality (named Areas II and IV) 6-9 years after deploying sustained vector control interventions. Multiple logistic regression models were used to evaluate the relationship between human infection and a priori selected predictors. Two risk indices were constructed based on environmental and serostatus variables, and we used spatial analysis to test whether households harboring T. cruzi-seropositive children were randomly distributed.

RESULTS

The global seroprevalence of T. cruzi infection was 24.8%. Human infection was positively and significantly associated with exposure time to triatomines, the household number of seropositive co-inhabitants, maternal seropositivity for T. cruzi, recent residence at the current house and the presence of suitable walls for triatomine colonization in the domicile. The pre-intervention mean annual force of infection (FOI) was 1.23 per 100 person-years. Creoles from Area IV exhibited the highest seroprevalence and FOI; Qom people from both areas displayed intermediate ones and creoles from Area II the lowest. Three hotspots of infected children were spatially associated with hotspots of triatomine abundance at baseline and persistent house infestation. No child born after vector control interventions was T. cruzi seropositive except for one putative transplacental case. Two simple risk indices (based on self-reported inhabiting an infested house and suitable walls for triatomines or maternal serostatus) identified 97.3-98.6% of the households with at least one T. cruzi-seropositive child.

CONCLUSIONS

We showed strong heterogeneity in the seroprevalence of T. cruzi infection within and between ethnic groups inhabiting neighboring rural areas. Developed indices can be used for household risk stratification and to improve access of rural residents to serodiagnosis and treatment and may be easily transferred to primary healthcare personnel.

The COVID-19 Severity and Its Association with Intestinal Parasite Coinfection and Urine Biochemical Parameters among COVID-19-Confirmed Patients Admitted to Debre Markos University COVID-19 Center, Northwest Ethiopia

Background

Though most people with COVID-19 disease show asymptomatic to mild illness, a substantial number of patients are at high risk of developing severe disease and adverse outcomes with long COVID-19 and death. Even though some studies showed that previously existing infections with parasites amend the host's body defenses to increase resistance to infection with SARS-CoV-2, there is limited data in Ethiopia.

Objectives

This study is aimed at determining the COVID-19 disease severity and its association with intestinal parasite coinfection and urine biochemical parameters among COVID-19-confirmed patients admitted at Debre Markos University COVID-19 Center, 2021.

Methods

A prospective cohort study was conducted on 136 RT-qPCR-confirmed COVID-19 patients admitted at Debre Markos University COVID-19 Center from January 1 to March 30, 2021. Sociodemographic and clinical data were collected by using standardized data collection forms. A urine biochemical test was performed using a dry urine dipstick kit and stool examination using direct wet mount microscopic examination and formalin-ether concentration method. The chi-square test, Fisher exact test, and ordinal logistic regression analysis were computed to assess association with outcome variables using Statistical Package for Social Science software (version 24).

Result

A total of 136 COVID-19-confirmed patients participated in this study. The median age of the participants was 48 years. The majority (86 (62.5%)) of them were male in sex. Of the 136 cases, 39 (28.7%) had died. Among the 136 patients, 22 (16.2%) were coinfected with intestinal parasites. COVID-19 patients who have intestinal parasite coinfection had lower odds of developing clinically severe COVID-19 compared to noninfected (AOR = 0.37; 95% CI = 0.147-0.944; P = 0.037). The majority (104 (76.5%)) of them have abnormal urine biochemical results. From the abnormal urine biochemical tests observed, the urine blood, glucose, and ketone tests were positive for 54 (39.7%), 36 (26.5%), and 30 (21.1%) patients, respectively. Among the 31 critical COVID-19 patients, 25 (80.6%) showed abnormal urine biochemical parameters. Age and comorbidity were significantly associated with COVID-19 severity (P < 0.05).

Conclusion

Patients with old age and comorbidity had an increased risk of developing severe COVID-19 disease. Patients having SARS-CoV-2 and intestinal parasitic coinfections demonstrated mild COVID-19 disease severity. Abnormal urine biochemical results were common among critical COVID-19 patients. Thus, advanced study on the effect of the interaction among intestinal parasites on COVID-19 clinical severity and its mechanisms is essential.

Antigiardial and antiamebic activities of fexinidazole and its metabolites: new drug leads for giardiasis and amebiasis

The intestinal parasites Giardia lamblia and Entamoeba histolytica are major causes of morbidity and mortality associated with diarrheal diseases. Metronidazole is the most common drug used to treat giardiasis and amebiasis. Despite its efficacy, treatment failures in giardiasis occur in up to 5%-40% of cases. Potential resistance of E. histolytica to metronidazole is an increasing concern. Therefore, it is critical to search for more effective drugs to treat giardiasis and amebiasis. We identified antigiardial and antiamebic activities of the rediscovered nitroimidazole compound, fexinidazole, and its sulfone and sulfoxide metabolites. Fexinidazole is equally active against E. histolytica and G. lamblia trophozoites, and both metabolites were 3- to 18-fold more active than the parent drug. Fexinidazole and its metabolites were also active against a metronidazole-resistant strain of G. lamblia. G. lamblia and E. histolytica cell extracts exhibited decreased residual nitroreductase activity when metabolites were used as substrates, indicating nitroreductase may be central to the mechanism of action of fexinidazole. In a cell invasion model, fexinidazole and its metabolites significantly reduced the invasiveness of E. histolytica trophozoites through basement membrane matrix. A q.d. oral dose of fexinidazole and its metabolites at 10 mg/kg for 3 days reduced G. lamblia infection significantly in mice compared to control. The newly discovered antigiardial and antiamebic activities of fexinidazole, combined with its FDA-approval and inclusion in the WHO Model List of Essential Medicines for the treatment of human African trypanosomiasis, offer decreased risk and a shortened development timeline toward clinical use of fexinidazole for treatment of giardiasis or amebiasis.

High-throughput detection of parasites and ova in stool using the fully automatic digital feces analyzer, orienter model fa280

BACKGROUND

Intestinal parasitic infections can harm health by causing malnutrition, anemia, impaired growth and cognitive development, and alterations in microbiota composition and immune responses. Therefore, it is crucial to examine stool samples to diagnose parasitic infections. However, the traditional microscopic detection method is time-consuming, labor-intensive, and dependent on the expertise and training of microscopists. Hence, there is a need for a low-complexity, high-throughput, and cost-effective alternative to labor-intensive microscopic examinations.

METHODS

This study aimed to compare the performance of a fully automatic digital feces analyzer, Orienter Model FA280 (People's Republic of China) with that of the formalin-ethyl acetate concentration technique (FECT). We assessed and compared the agreement between the FA280 and the FECT for parasite detection and species identification in stool samples. The first part of the study analyzed 200 fresh stool samples for parasite detection using the FECT and FA280. With the FA280, the automatic feces analyzer performed the testing, and the digital microscope images were uploaded and automatically evaluated using an artificial intelligence (AI) program. Additionally, a skilled medical technologist conducted a user audit of the FA280 findings. The second set of samples comprised 800 preserved stool samples (preserved in 10% formalin). These samples were examined for parasites using the FECT and FA280 with a user audit.

RESULTS

For the first set of stool samples, there was no statistically significant difference in the pairwise agreements between the FECT and the FA280 with a user audit (exact binomial test, P = 1). However, there were statistically significant differences between the pairwise agreements for the FECT and the FA280 with the AI report (McNemar's test, P < 0.001). The agreement for the species identification of parasites between the FA280 with AI report and FECT showed fair agreement (overall agreement = 75.5%, kappa [κ] = 0.367, 95% CI 0.248-0.486). On the other hand, the user audit for the FA280 and FECT showed perfect agreement (overall agreement = 100%, κ = 1.00, 95% CI 1.00-1.00). For the second set of samples, the FECT detected significantly more positive samples for parasites than the FA280 with a user audit (McNemar's test, P < 0.001). The disparity in results may be attributed to the FECT using significantly larger stool samples than those used by the FA280. The larger sample size used by the FECT potentially contributed to the higher parasite detection rate. Regarding species identification, there was strong agreement between the FECT and the FA280 with a user audit for helminths (κ = 0.857, 95% CI 0.82-0.894). Similarly, there was perfect agreement for the species identification of protozoa between the FECT and the FA280 with user audit (κ = 1.00, 95% CI 1.00-1.00).

CONCLUSIONS

Although the FA280 has advantages in terms of simplicity, shorter performance time, and reduced contamination in the laboratory, there are some limitations to consider. These include a higher cost per sample testing and a lower sensitivity compared to the FECT. However, the FA280 enables rapid, convenient, and safe stool examination of parasitic infections.

Nanotechnological approaches in the treatment of schistosomiasis: an overview

Schistosomiasis causes over 200,000 deaths annually. The current treatment option, praziquantel, presents limitations, including low bioavailability and resistance. In this context, nanoparticles have emerged as a promising option for improving schistosomiasis treatment. Several narrative reviews have been published on this topic. Unfortunately, the lack of clear methodologies presented in these reviews leads to the exclusion of many important studies without apparent justification. This integrative review aims to examine works published in this area with a precise and reproducible method. To achieve this, three databases (i.e., Pubmed, Web of Science, and Scopus) were searched from March 31, 2022, to March 31, 2023. The search results included only original research articles that used nanoparticles smaller than 1 µm in the treatment context. Additionally, a search was conducted in the references of the identified articles to retrieve works that could not be found solely using the original search formula. As a result, 65 articles that met the established criteria were identified. Inorganic and polymeric nanoparticles were the most prevalent nanosystems used. Gold was the primary material used to produce inorganic nanoparticles, while poly(lactic-co-glycolic acid) and chitosan were commonly used to produce polymeric nanoparticles. None of these identified works presented results in the clinical phase. Finally, based on our findings, the outlook appears favorable, as there is a significant diversity of new substances with schistosomicidal potential. However, financial efforts are required to advance these nanoformulations.

The long-lasting Ascaris suum antigens in the lungs shapes the tissue adaptation modifying the pulmonary architecture and immune response after infection in mice

Ascariasis is the most prevalent helminth affecting approximately 819 million people worldwide. The acute phase of Ascariasis is characterized by larval migration of Ascaris spp., through the intestinal wall, carried to the liver and lungs of the host by the circulatory system. Most of the larvae subsequently transverse the lung parenchyma leading to tissue injury, reaching the airways and pharynx, where they can be expectorated and swallowed back to the gastrointestinal tract, where they develop into adult worms. However, some larvae are trapped in the lung parenchyma inciting an inflammatory response that causes persistent pulmonary tissue damage long after the resolution of infection, which returns to tissue homeostasis. However, the mechanism by which chronic lung disease develops and resolves remains unknown. Here, using immunohistochemistry, we demonstrate that small fragments and larval antigens of Ascaris suum are deposited and retained chronically in the lung parenchyma of mice following a single Ascaris infection. Our results reveal that the prolonged presence of Ascaris larval antigens in the lung parenchyma contributes to the persistent immune stimulation inducing histopathological changes observed chronically following infection, and clearly demonstrate that larval antigens are related to all phases of tissue adaptation after infection: lung injury, chronic inflammation, resolution, and tissue remodeling, in parallel to increased specific humoral immunity and the recovery of lung function in mice. Additional insight is needed into the mechanisms of Ascaris antigen to induce chronic immune responses and resolution in the host lungs following larval migration.

The global burden of neglected zoonotic diseases: Current state of evidence

The majority of emerging infectious diseases are zoonoses, most of which are classified as "neglected". By affecting both humans and animals, zoonoses pose a dual burden. The disability-adjusted life year (DALY) metric quantifies human health burden since it combines mortality and morbidity. This review aims to describe and analyze the current state of evidence on neglected zoonotic diseases (NZDs) burden and start a discussion on the current understanding of the global burden of NZDs. We identified 26 priority NZDs through consulting three international repositories for national prioritization exercises. A systematic review of global and national burden of disease (BoD) studies was conducted using pre-selected databases. Data on diseases, location and DALYs were extracted for each eligible study. A total of 1887 records were screened, resulting in 74 eligible studies. The highest number of BoD was found for non-typhoidal salmonellosis (23), whereas no estimates were found for West Nile, Marburg and Lassa fever. Geographically, the highest number of studies was performed in the Netherlands (11), China (5) and Iran (4). The number of BoD retrieved mismatched the perceived importance in national prioritization exercises. For example, anthrax was considered a priority NZD in 65 countries; however, only one national study estimating BoD was retrieved. By summing the available global estimates, the selected NZDs caused at least 21 million DALYs per year, a similar order of magnitude to (but less than) the burden due to foodborne disease (included in the Foodborne Disease Burden Epidemiology Reference Group). The global burden of disease landscape of NZDs remains scattered. There are several priority NZDs for which no burden estimates exist, and the number of BoD studies does not reflect national disease priorities. To have complete and consistent estimates of the global burden of NZDs, these diseases should be integrated in larger global burden of disease initiatives.

Dynamics of co-infection in fish: A review of pathogen-host interaction and clinical outcome

Co-infections can affect the transmission of a pathogen within a population and the pathogen's virulence, ultimately affecting the disease's dynamics. In addition, co-infections can potentially affect the host's immunological responses, clinical outcomes, survival, and disease control efficacy. Co-infections significantly impact fish production and can change several fish diseases' progression and severity. However, the effect of co-infection has only recently garnered limited attention in aquatic animals such as fish, and there is currently a dearth of studies on this topic. This study, therefore, presents an in-depth summary of the dynamics of co-infection in fish. This study reviewed the co-infection of fish pathogens, the interaction of pathogens and fish, clinical outcomes and impacts on fish immune responses, and fish survival. Most studies described the prevalence of co-infections in fish, with various parameters influencing their outcomes. Bacterial co-infection increased fish mortality, ulcerative dermatitis, and intestinal haemorrhage. Viral co-infection resulted in osmoregulatory effects, increased mortality and cytopathic effect (CPE). More severe histological alterations and clinical symptoms were related to the co-infection of fish than in single-infected fish. In parasitic co-infection, there was increased mortality, high kidney swelling index, and severe necrotic alterations in the kidney, liver, and spleen. In other cases, there were more severe kidney lesions, cartilage destruction and displacement. There was a dearth of information on mitigating co-infections in fish. Therefore, further studies on the mitigation strategies of co-infections in fish will provide valuable insights into this research area. Also, more research on the immunology of co-infection specific to each fish pathogen class (bacteria, viruses, fungi, and parasites) is imperative. The findings from such studies would provide valuable information on the relationship between fish immune systems and targeted responses.

Case studies of clinical decision-making through prescriptive models based on machine learning

BACKGROUND

The development of computational methodologies to support clinical decision-making is of vital importance to reduce morbidity and mortality rates. Specifically, prescriptive analytic is a promising area to support decision-making in the monitoring, treatment and prevention of diseases. These aspects remain a challenge for medical professionals and health authorities.

MATERIALS AND METHODS

In this study, we propose a methodology for the development of prescriptive models to support decision-making in clinical settings. The prescriptive model requires a predictive model to build the prescriptions. The predictive model is developed using fuzzy cognitive maps and the particle swarm optimization algorithm, while the prescriptive model is developed with an extension of fuzzy cognitive maps that combines them with genetic algorithms. We evaluated the proposed approach in three case studies related to monitoring (warfarin dose estimation), treatment (severe dengue) and prevention (geohelminthiasis) of diseases.

RESULTS

The performance of the developed prescriptive models demonstrated the ability to estimate warfarin doses in coagulated patients, prescribe treatment for severe dengue and generate actions aimed at the prevention of geohelminthiasis. Additionally, the predictive models can predict coagulation indices, severe dengue mortality and soil-transmitted helminth infections.

CONCLUSIONS

The developed models performed well to prescribe actions aimed to monitor, treat and prevent diseases. This type of strategy allows supporting decision-making in clinical settings. However, validations in health institutions are required for their implementation.

Functional characterization of three G protein-coupled acetylcholine receptors in parasitic nematode Trichinella spiralis

The physiological significance of metabotropic acetylcholine receptors in parasitic nematodes remains largely unexplored. Here, three different Trichinella spiralis G protein-coupled acetylcholine receptors (TsGAR-1, -2, and -3) were identified in the genome of T. spiralis. The phylogenetic analyses showed that TsGAR-1 and -2 receptors belong to a distinct clade specific to invertebrates, while TsGAR-3 is closest to the cluster of mammalian-type muscarinic acetylcholine receptors (mAChR). The mRNA of TsGAR-1, -2, and -3 was detected in muscle larvae, newborn larvae, and adults. The functional aequorin-based assay in Chinese hamster ovary cells revealed that all three types of T. spiralis GARs trigger the Gq/11 pathway upon activation of the receptor with the acetylcholine ligand. TsGAR-1 and TsGAR-2 showed atypical affinity with classical muscarinic agonists, while TsGAR-3 was sensitive to all muscarinic agonists tested. High concentrations of propiverine antagonist blocked the activities of all three TsGARs, while atropine and scopolamine antagonists effectively inhibited only TsGAR-3. Our data indicate that the distinct pharmacological profile of TsGAR-1 and -2 receptors, as well as the phylogenetic distance between them and their mammalian orthologs, place them as attractive targets for the development of selective anthelmintic drugs interfering with nematodes' cholinergic system.

Variants of IL6, IL10, FCN2, RNASE3, IL12B and IL17B loci are associated with Schistosoma mansoni worm burden in the Albert Nile region of Uganda

BACKGROUND

Individuals genetically susceptible to high schistosomiasis worm burden may contribute disproportionately to transmission and could be prioritized for control. Identifying genes involved may guide development of therapy.

METHODOLOGY/PRINCIPAL FINDINGS

A cohort of 606 children aged 10-15 years were recruited in the Albert Nile region of Uganda and assessed for Schistosoma mansoni worm burden using the Up-Converting Particle Lateral Flow (UCP-LF) test detecting circulating anodic antigen (CAA), point-of-care Circulating Cathodic Antigen (POC-CCA) and Kato-Katz tests. Whole genome genotyping was conducted on 326 children comprising the top and bottom 25% of worm burden. Linear models were fitted to identify variants associated with worm burden in preselected candidate genes. Expression quantitative trait locus (eQTL) analysis was conducted for candidate genes with UCP-LF worm burden included as a covariate. Single Nucleotide Polymorphism loci associated with UCP-LF CAA included IL6 rs2066992 (OR = 0.43, p = 0.0006) and rs7793163 (OR = 2.0, p = 0.0007); IL21 SNP kgp513476 (OR 1.79, p = 0.0025) and IL17B SNP kgp708159 (OR = 0.35, p = 0.0028). A haplotype in the IL10 locus was associated with lower worm burden (OR = 0.53, p = 0.015) and overlapped SNPs rs1800896, rs1800871 and rs1800872. Significant haplotypes (p<0.05, overlapping significant SNP) associated with worm burden were observed in IL6 and the Th17 pathway IL12B and IL17B genes. There were significant eQTL in the IL6, IL5, IL21, IL25 and IFNG regions.

CONCLUSIONS

Variants associated with S. mansoni worm burden were in IL6, FCN2, RNASE3, IL10, IL12B and IL17B gene loci. However only eQTL associations remained significant after Bonferroni correction. In summary, immune balance, pathogen recognition and Th17 pathways may play a role in modulating Schistosoma worm burden. Individuals carrying risk variants may be targeted first in allocation of control efforts to reduce the burden of schistosomiasis in the community.

A cross-sectional analysis of publication of pediatric global health abstracts from seven major international conferences

Research presented at conferences may increase context-specific evidence in low- and middle-income countries (LMICs), where global childhood disease burden is greatest and where massive relative deficits in research persist. Publication of studies presented at conferences is necessary for complete results dissemination. Our objective was to determine the frequency of publication of pediatric global health conference abstracts and to identify factors associated with publication. We conducted a cross-sectional study of abstracts that reported pediatric research conducted in at least one LMIC presented at seven major scientific conferences in 2017, 2018, and 2019. We used PubMed, EMBASE and Google Scholar to search for publications of the results presented as abstracts. We created a Kaplan-Meier curve to determine the cumulative incidence of publications and used predetermined abstract-level factors to create a multivariable Cox proportional hazard model to identify factors associated with time to publication. There were 8,105 abstracts reviewed and 1,433 (17.7%) reported pediatric research conducted in one or more LMICs. The probability of publication of pediatric global health abstracts was 33.6% (95% confidence interval [CI] 31.2-36.1%) at 24 months and 46.6% (95% CI 44.0-49.3%) at 48 months. Abstracts that reported research conducted in East Asia and Pacific (adjusted hazard ratio [aHR] 3.06, 95% CI 1.74-5.24), South Asia (aHR 2.25, 95% CI 1.30-3.91%), and upper-middle-income countries (1.50, 95% CI 1.12-2.02) were published sooner than those that reported research in LMICs in Europe and Central Asia and lower-middle-income countries, respectively. Fewer than half of pediatric global health abstracts were published in peer-reviewed journals up to four years after presentation at international conferences. Efforts are urgently needed to promote the widespread and long-lasting dissemination of pediatric research conducted in LMICs presented as abstracts to provide a more robust evidence base for both clinical care and policy related to child health.

Stem cell proliferation and differentiation during larval metamorphosis of the model tapeworm Hymenolepis microstoma

Background

Tapeworm larvae cause important diseases in humans and domestic animals. During infection, the first larval stage undergoes a metamorphosis where tissues are formed de novo from a population of stem cells called germinative cells. This process is difficult to study for human pathogens, as these larvae are infectious and difficult to obtain in the laboratory.

Methods

In this work, we analyzed cell proliferation and differentiation during larval metamorphosis in the model tapeworm Hymenolepis microstoma, by in vivo labelling of proliferating cells with the thymidine analogue 5-ethynyl-2'-deoxyuridine (EdU), tracing their differentiation with a suite of specific molecular markers for different cell types.

Results

Proliferating cells are very abundant and fast-cycling during early metamorphosis: the total number of cells duplicates every ten hours, and the length of G2 is only 75 minutes. New tegumental, muscle and nerve cells differentiate from this pool of proliferating germinative cells, and these processes are very fast, as differentiation markers for neurons and muscle cells appear within 24 hours after exiting the cell cycle, and fusion of new cells to the tegumental syncytium can be detected after only 4 hours. Tegumental and muscle cells appear from early stages of metamorphosis (24 to 48 hours post-infection); in contrast, most markers for differentiating neurons appear later, and the detection of synapsin and neuropeptides correlates with scolex retraction. Finally, we identified populations of proliferating cells that express conserved genes associated with neuronal progenitors and precursors, suggesting the existence of tissue-specific lineages among germinative cells.

Discussion

These results provide for the first time a comprehensive view of the development of new tissues during tapeworm larval metamorphosis, providing a framework for similar studies in human and veterinary pathogens.

Miniature spatial transcriptomics for studying parasite-endosymbiont relationships at the micro scale

Several important human infectious diseases are caused by microscale-sized parasitic nematodes like filarial worms. Filarial worms have their own spatial tissue organization; to uncover this tissue structure, we need methods that can spatially resolve these miniature specimens. Most filarial worms evolved a mutualistic association with endosymbiotic bacteria Wolbachia. However, the mechanisms underlying the dependency of filarial worms on the fitness of these bacteria remain unknown. As Wolbachia is essential for the development, reproduction, and survival of filarial worms, we spatially explored how Wolbachia interacts with the worm's reproductive system by performing a spatial characterization using Spatial Transcriptomics (ST) across a posterior region containing reproductive tissue and developing embryos of adult female Brugia malayi worms. We provide a proof-of-concept for miniature-ST to explore spatial gene expression patterns in small sample types, demonstrating the method's ability to uncover nuanced tissue region expression patterns, observe the spatial localization of key B. malayi - Wolbachia pathway genes, and co-localize the B. malayi spatial transcriptome in Wolbachia tissue regions, also under antibiotic treatment. We envision our approach will open up new avenues for the study of infectious diseases caused by micro-scale parasitic worms.

Neglected Tropical Diseases in Italy: introducing IN-NTD, the Italian network for NTDs

The World Health Organization (WHO) defines neglected tropical diseases (NTDs) as a diverse group of primarily infectious diseases, which disproportionately affect poor and marginalized populations worldwide. In this context, NTDs are responsible for important morbidity and mortality and justify a global response. Moreover, NTDs are relatively neglected by research and development as well as by funding, if compared with the magnitude of the public health problem they represent. This happens even though, unlike other infectious diseases, they can be prevented, controlled and eliminated by targeted public health interventions. NTDs are mainly prevalent in communities from low-income countries in tropical and sub-tropical areas but are also present in upper–middle-income countries, including several in Europe. Here, we provide an update on the most relevant parasitic endemic or imported NTDs in Italy and illustrate the rationale for the establishment of the Italian network on NTDs, an alliance of scientific societies, institutes, foundations, universities and non-profit organizations united to fight NTDs.

Towards an integrated vector management approach for sustainable control of schistosomiasis and malaria in Mwea, Kirinyaga County, Kenya: Baseline epidemiological and vector results

Background

Vector control is an important approach in the control of most parasitic and vector-borne diseases including malaria, and schistosomiasis. Distribution of these two infections often overlaps and in such areas it's more economically viable to employ an integrated approach in the control of their vectors which largely shares the same breeding ecosystem. We carried out a baseline epidemiological and vector surveys for malaria and schistosomiasis in Mwea, Kirinyaga County, in preparation for the upscaling of integrated vector management (IVM) for the two diseases.

Methods

This was a repeated cross sectional survey, where mosquito and snails were sampled during dry and wet seasons in three different ecological zones, Kiamaciri, Thiba and Murinduko to identify possible breeding sites. Mosquito larvae were collected using standard dippers, adults using CDC miniature light traps while snail vectors were sampled using standard snail scoops in different breeding habitats. A total of 1200 pupils from 12 primary schools were tested for malaria using rapid diagnostic tests (Malaria Pf/PAN Ag combo). Stool samples were processed using the Kato Katz technique for intestinal schistosomiasis.

Results

The overall prevalence of intestinal schistosomiasis was 9.08 % (95 % CI: 07.00-11.00), with Kiamaciri zone recording the highest prevalence at 19 % (95%CI: 15.00-23.00) and Murinduko zone the least at 0.17 % (95%CI: 0.00-0.01). Majority of the infections were of light intensity 78.9 % (95%CI: 70.04-86.13). There was no positive malaria case detected in this study. Of the 3208 adult mosquitoes sampled during the dry season, 20.6 % (95 % CI: 19.25-22.08) were Anopheles gambiae s.l while 79.4 % (95 % CI: 77.92-80.75) were culicines. During the wet season, 3378 adult mosquitoes were collected, of which 14.7 % (95 % CI: 13.56-15.98) were Anopheles gambiae s.l and 85.3 % (95 % CI: 84.02-86.44) culicines. Overall, 4085 mosquito larvae were collected during the two seasons, of which, 57.3 % and 42.7 % were anopheles and culicine respectively. Majority of the larvae (85.1 % (95%CI: 84.01-86.10) were collected during the wet season, with only 14.9 % (95%CI: 14.10-16.00) being collected during the dry season. A total of 2292 fresh water vector snails were collected with a majority (69.6 % (95%CI: 68.00-71.10) being Biomphalaria pffeiferi responsible for transmission of intestinal schistosomiasis.

Conclusion

This study demonstrates that intestinal schistosomiasis is prevalent in Kiamaciri and Thiba zones, and points to the possibility of active transmission of schistosomiasis in Murinduko zone. Malaria vectors were predominantly observed in all sites despite there being no malaria positive case. Culex quinquefaciatus responsible for the spread of several arboviruses was also observed. The presence of these vectors may lead to future disease outbreaks in the area if concerted control initiatives are not undertaken. The disease vectors shared the same breeding sites and thus its economical and feasible to adopt an integrated vector management approach in control efforts for these disease in the study area.

Metagenomic sequencing for identifying pathogen-specific circulating DNAs and development of diagnostic methods for schistosomiasis

Timely diagnosis of Schistosoma infection, particularly in the early stage is crucial for identifying infected hosts and then taking effective control strategies. Here, metagenomic next-generation sequencing was used to identify pathogen-specific circulating DNAs (cDNAs) in the sera/plasma of New Zealand rabbits infected with S. japonicum, and the identified cDNAs were validated by PCR and qPCR. Loop-mediated isothermal amplification (LAMP)-based CRISPR-Cas12a and recombinase polymerase amplification-based lateral flow strip (RPA-LF) methods combined with the newly identified cDNA were developed to evaluate the potentials for diagnosing murine and human schistosomiasis. The results indicated that twenty-two cDNAs were identified. The developed LAMP-based CRISPR/Cas12a and RPA-LF methods showed a good potential for diagnosing murine or human schistosomiasis as early as 5 days of post-infection with 5 cercariae infection. In a word, S. japonicum specific cDNAs in circulation of infected hosts could be effective biomarkers for detecting Schistosoma infection particularly for early stages.

Temperature affects predation of schistosome-competent snails by a novel invader, the marbled crayfish Procambarus virginalis

The human burden of environmentally transmitted infectious diseases can depend strongly on ecological factors, including the presence or absence of natural enemies. The marbled crayfish (Procambarus virginalis) is a novel invasive species that can tolerate a wide range of ecological conditions and colonize diverse habitats. Marbled crayfish first appeared in Madagascar in 2005 and quickly spread across the country, overlapping with the distribution of freshwater snails that serve as the intermediate host of schistosomiasis-a parasitic disease of poverty with human prevalence ranging up to 94% in Madagascar. It has been hypothesized that the marbled crayfish may serve as a predator of schistosome-competent snails in areas where native predators cannot and yet no systematic study to date has been conducted to estimate its predation rate on snails. Here, we experimentally assessed marbled crayfish consumption of uninfected and infected schistosome-competent snails (Biomphalaria glabrata and Bulinus truncatus) across a range of temperatures, reflective of the habitat range of the marbled crayfish in Madagascar. We found that the relationship between crayfish consumption and temperature is unimodal with a peak at ~27.5°C. Per-capita consumption increased with body size and was not affected either by snail species or their infectious status. We detected a possible satiation effect, i.e., a small but significant reduction in per-capita consumption rate over the 72-hour duration of the predation experiment. Our results suggest that ecological parameters, such as temperature and crayfish weight, influence rates of consumption and, in turn, the potential impact of the marbled crayfish invasion on snail host populations.

Highly cited tropical medicine articles in the Web of Science from 1991 to 2020: A bibliometric analysis

BACKGROUND

An adequate response to health needs to include the identification of research patterns about the large number of people living in the tropics and subjected to tropical diseases. Studies have shown that research does not always match the real needs of those populations, and that citation reflects mostly the amount of money behind particular publications. Here we test the hypothesis that research from richer institutions is published in better-indexed journals, and thus has greater citation rates.

METHODS

The data in this study were extracted from the Science Citation Index Expanded database; the 2020 journal Impact Factor (IF2020) was updated to 30 June 2021. We considered places, subjects, institutions and journals.

RESULTS

We identified 1041 highly cited articles with ≥100 citations in the category of tropical medicine. About a decade is needed for an article to reach peak citation. Only two COVID-19-related articles were highly cited in the last 3 y. The most cited articles were published by the journals Memorias Do Instituto Oswaldo Cruz (Brazil), Acta Tropica (Switzerland) and PLoS Neglected Tropical Diseases (USA). The USA dominated five of the six publication indicators. International collaboration articles had more citations than single-country articles. The UK, South Africa and Switzerland had high citation rates, as did the London School of Hygiene and Tropical Medicine in the UK, the Centers for Disease Control and Prevention in the USA and the WHO in Switzerland.

CONCLUSIONS

About 10 y of accumulated citations is needed to achieve ≥100 citations as highly cited articles in the Web of Science category of tropical medicine. Six publication and citation indicators, including authors' publication potential and characteristics evaluated by Y-index, indicate that the currently available indexing system places tropical researchers at a disadvantage against their colleagues in temperate countries, and suggest that, to progress towards better control of tropical diseases, international collaboration should increase, and other tropical countries should follow the example of Brazil, which provides significant financing to its scientific community.

Cytokine Gene Expression Profiles during HIV and Helminth Coinfection in Underprivileged Peri-Urban South African Adults

BACKGROUND

Intestinal helminth parasites are potent stimulators of T helper type 2 (Th2) and regulatory Th3 anti-inflammatory immune responses, while human immunodeficiency virus (HIV) infections are activators of predominantly T helper type 1(Th1) pro-inflammatory responses. Studies investigating the immune profiles of individuals coinfected with helminths and HIV are scarce. Although it is well known that helminths cause a type 2 immune response during the chronic stage of infection that is characterised by Th2 cell differentiation, eosinophil recruitment, and alternative macrophage activation, the immune mechanisms that regulate tissue damage at the time of parasite invasion are poorly understood.

AIM

The aim of the study was to determine the cytokine gene expression profiles during HIV and helminth coinfection in underprivileged South African adults living in a peri-urban area with poor sanitary conditions and a lack of clean water supply.

METHOD

Study participants (n = 164) were subdivided into uninfected controls, HIV-infected, helminth-infected, and HIV and helminth-coinfected groups. The Kato-Katz and Mini Parasep techniques and Ascaris lumbricoides-specific Immunoglobulin E (IgE) and Immunoglobulin G4 (IgG4) levels were used to detect helminth infections. Participants' HIV status was determined using two HIV1/2 antibody test kits. RNA was isolated from white blood cells for cytokine (Th1-, Th2-, and Th17-related) and transcription factor gene expression profiling using real-time PCR.

RESULTS

Multivariate regression data were adjusted for age, gender, BMI, antiretroviral treatment (ART), and nutritional supplement intake. The HIV and helminth-coinfected group had significantly higher tumour necrosis factor alpha (TNF-α) (adjusted β = 0.53, p = 0.036), interleukin 2 (IL-2) (adjusted β = 6.48, p = 0.008), and interleukin 17 (IL-17) (adjusted β = 1.16, p = 0.001) levels and lower GATA binding protein 3 (GATA3) levels (adjusted β = -0.77, p = 0.018) compared to the uninfected controls. No statistical significance was noted for Th2-related cytokines.

CONCLUSION

The coinfected group had higher proinflammatory Th1- and Th17-related cytokine gene expression profiles compared to the uninfected controls. The findings suggest that pro-inflammatory responses are elevated during coinfection, which supports the hypothesis that helminths have a deleterious effect on HIV immune responses.