Human schistosomiasis: A diagnostic imaging focused review of a neglected disease

Development and evaluation of the in vitro schistosomicidal activity of solid dispersions based on 2-(-5-bromo-1-H-indole-3-yl-methylene)-N-(naphthalene-1-ylhydrazine-carbothiamide

Among all the neglected diseases, schistosomiasis is considered the second most important parasitic infection after malaria. Praziquantel is the most widely used drug for this disease, but its exclusive use may result in the development of drug-resistant schistosomiasis. To increase the control of the disease, new drugs have been developed as alternative treatments, among them 2-(-5-bromo-1-h-indole-3-yl-methylene)-N-(naphthalene-1-ylhydrazine-carbothiamide (LQIT/LT-50), which showed promising schistosomicidal activity in nonclinical studies. However, LQIT/LT-50 presents low solubility in water, resulting in reduced bioavailability. To overcome this solubility problem, the present study aimed to develop LQIT/LT-50 solid dispersions for the treatment of schistosomiasis. Solid dispersions were prepared through the solvent method using Soluplus©, polyethylene glycol (PEG) or polyvinylpyrrolidone (PVP K-30) as hydrophilic carriers. The formulations with the best results in the compatibility tests, aqueous solubility and preliminary stability studies have undergone solubility tests and physicochemical characterizations by Fourier-transform infrared spectroscopy (FTIR), x-ray diffractometry (XRD), exploratory differential calorimetry (DSC), thermogravimetry (TG) and Raman spectroscopy. Finally, the schistosomicidal activity was evaluated in vitro. The phycochemical analyzes showed that when using PVP K-30, there was an interaction between the PVP K-30 and LQIT/LT-50, proving the successful development of the solid dispersion. Furthermore, an increase in the solubility of the new system was observed (LQIT/LT-50:PVP K-30) in addition to the improvement in the in vitro shistosomidal activity at 1:4 (w/w) molar ratio (i.e., 20% drug loading) when compared to LQIT/LT-50 alone. The development of the LQIT/LT-50:PVP K-30 1:4 solid dispersion is encouraging for the future development of new pharmaceutical solid formulations, aiming the schistosomicidal treatment.

Misdiagnosis of Hepatosplenic Schistosomiasis as Hepatic Tuberculosis: A Case Report

We report a case of a 38-year-old woman who was initially misdiagnosed with hepatic tuberculosis and was managed as such before being correctly diagnosed with hepatosplenic schistosomiasis on liver biopsy. The patient had a five-year history of jaundice which over time was accompanied by polyarthritis and then abdominal pain. A diagnosis of hepatic tuberculosis was made clinically and supported by radiographic evidence. She underwent an open cholecystectomy for gallbladder hydrops with the liver biopsy taken revealing chronic hepatic schistosomiasis and was eventually started on praziquantel with good recovery. This case demonstrates a diagnostic issue with the radiographic presentation of the patient and the important role of tissue biopsy in providing definitive care.

Simplifying Schistosome Surveillance: Using Molecular Cercariometry to Detect and Quantify Cercariae in Water

Avian schistosomes are considered a public health nuisance due to their ability to cause swimmer’s itch when accidentally encountering humans rather than their intended avian hosts. Researchers have been monitoring their presence and abundance through snail collections and cercariometry. Cercariometry methods have evolved over the last several decades to detect individual schistosome species from a single water sample, simplifying the monitoring of these parasites. This methodological evolution coincides with the development of the field of environmental DNA (eDNA) where genetic material is extracted from environmental samples, rather than individual organisms. While there are some limitations with using molecular cercariometry, notably the cost and its inability to differentiate between life cycle stages, it substantially reduces the labor required to study trematode populations. It also can be used in complement with snail collections to understand the composition of avian schistosomes in an environment.

Noninvasive diagnosis of periportal fibrosis in schistosomiasis mansoni: A comprehensive review

Schistosomiasis mansoni is a neglected disease and key public health problem, mainly due to its high prevalence, the scarcity of public policies, and the severity of some clinical forms. Periportal fibrosis (PPF) is the commonest complication of chronic schistosomiasis mansoni and its diagnosis requires different techniques. Even though wedge biopsy of the liver is considered the gold standard, it is not justified in non-surgical patients, and percutaneous liver biopsy may be informative but does not have sufficient sensitivity. Noninvasive PPF tests mostly include biological (serum biomarkers or combined scores) or physical assessments (imaging assessment of fibrosis pattern or tissue stiffness). Moreover, imaging techniques, such as ultrasound, computed tomography, magnetic resonance imaging, and elastography are applied not only to support the diagnosis of schistosomiasis, but also to assess and detect signs of portal hypertension and organ damage due to chronic schistosomiasis. A combination between a comprehensive history and physical examination with biomarkers for liver fibrosis and imaging methods seems to offer the best approach for evaluating these patients. In addition, understanding their strengths and limitations will allow a more accurate interpretation in the clinical context and can lead to greater accuracy in estimating the degree of fibrosis in patients with Schistosomiasis mansoni (S. mansoni) infection. This review will discuss the different noninvasive methods that are currently available for the evaluation of PPF in S. mansoni infection, and their application, advantages, and limitations in clinical practice.

An update on female and male genital schistosomiasis and a call to integrate efforts to escalate diagnosis, treatment and awareness in endemic and non-endemic settings: The time is now

The last decades have brought important insight and updates in the diagnosis, management and immunopathology of female genital schistosomiasis (FGS) and male genital schistosomiasis (MGS). Despite sharing a common parasitic aetiological agent, FGS and MGS have typically been studied separately. Infection with Schistosoma haematobium manifests with gender-specific clinical manifestations and consequences of infection, albeit having a similar pathogenesis within the human genital tract. Schistosoma haematobium is a known urinary bladder carcinogen, but its potential causative role in other types of neoplasia, such as cervical cancer, is not fully understood. Furthermore, the impact of praziquantel treatment on clinical outcomes remains largely underexplored, as is the interplay of FGS/MGS with relevant reproductive tract infections such as HIV and Human Papillomavirus. In non-endemic settings, travel and immigrant health clinics need better guidance to correctly identify and treat FGS and MGS. Our review outlines the latest advances and remaining knowledge gaps in FGS and MGS research. We aim to pave a way forward to formulate more effective control measures and discuss elimination targets. With a growing community awareness in health practitioners, scientists and epidemiologists, alongside the sufferers from these diseases, we aspire to witness a new generation of young women and men free from the downstream disabling manifestations of disease.

From the One Health Perspective: Schistosomiasis Japonica and Flooding

Schistosomiasis is a water-borne parasitic disease distributed worldwide, while schistosomiasis japonica localizes in the People’s Republic of China, the Philippines, and a few regions of Indonesia. Although significant achievements have been obtained in these endemic countries, great challenges still exist to reach the elimination of schistosomiasis japonica, as the occurrence of flooding can lead to several adverse consequences on the prevalence of schistosomiasis. This review summarizes the influence of flooding on the transmission of schistosomiasis japonica and interventions responding to the adverse impacts from the One Health perspective in human beings, animals, and the environment. For human and animals, behavioral changes and the damage of water conservancy and sanitary facilities will increase the intensity of water contact. For the environment, the density of Oncomelania snails significantly increases from the third year after flooding, and the snail habitats can be enlarged due to active and passive diffusion. With more water contact of human and other reservoir hosts, and larger snail habitats with higher density of living snails, the transmission risk of schistosomiasis increases under the influence of flooding. With the agenda set for global schistosomiasis elimination, interventions from the One Health perspective are put forward to respond to the impacts of increased flooding. For human beings, conducting health education to increase the consciousness of self-protection, preventive chemotherapy for high-risk populations, supply of safe water, early case finding, timely reporting, and treating cases will protect people from infection and prevent the outbreak of schistosomiasis. For animals, culling susceptible domestic animals, herding livestock in snail-free areas, treating livestock with infection or at high risk of infection, harmless treatment of animal feces to avoid water contamination, and monitoring the infection status of wild animals in flooding areas are important to cut off the transmission chain from the resources. For the environment, early warning of flooding, setting up warning signs and killing cercaria in risk areas during and post flooding, reconstructing damaged water conservancy facilities, developing hygiene and sanitary facilities, conducting snail surveys, using molluscicide, and predicting areas with high risk of schistosomiasis transmission after flooding all contribute to reducing the transmission risk of schistosomiasis. These strategies need the cooperation of the ministry of health, meteorological administration, water resources, agriculture, and forestry to achieve the goal of minimizing the impact of flooding on the transmission of schistosomiasis. In conclusion, flooding is one of the important factors affecting the transmission of schistosomiasis japonica. Multi-sectoral cooperation is needed to effectively prevent and control the adverse impacts of flooding on human beings, animals, and the environment.

Noninvasive Assessment of Schistosoma-Related Periportal Fibrosis

Schistosomiasis affects nearly 250 million individuals in the world. Hepatosplenic schistosomiasis (HSS) results in periportal fibrosis (PPF) and portal hypertension (pHTN). Ultrasound has been extensively used for the diagnosis of Schistosoma-related PPF and a number of staging methods have been validated for this purpose such as Strickland classification and Niamey protocol. Nevertheless, the application of noninvasive techniques, particularly elastography modalities, has not been well explored. In this review, we describe the various noninvasive diagnostic tools for assessment of Schistosoma-related PPF including US parameters, serum biomarkers, and US-based elastography techniques. While elastography techniques have demonstrated value in the evaluation of HSS, the evidence remains limited with most studies recruiting a small number of patients. Longitudinal studies with larger sample size are required in order to devise robust criteria to accurately assess the performance of noninvasive techniques in the prediction of both regression and progression of the degree of PPF and identify their cost-effectiveness in community screening.

Usefulness of ultrasound in sub-Saharan patients with a serological diagnosis of schistosomiasis

OBJECTIVE

To evaluate the usefulness of ultrasound examination in patients with just a serological diagnosis of schistosomiasis but no other evidence of active infection.

METHODS

346 sub-Saharan patients with possible schistosomiasis that presented at a Tropical Medicine Unit between 2008 and 2019 were retrospectively selected. Possible schistosomiasis was considered in those patients with a positive serology for schistosomasis in the absence of direct microbiological isolates, hematuria and/or eosinophilia. Data from ultrasound examinations before and after treatment with praziquantel were collected and categorized following the World Health Organization-Niamey score to standardize the use of ultrasonography for the assessment of schistosomiasis-related morbidity.

RESULTS

Ultrasound examinations were abnormal in only ten patients (2.89%). Main findings were focal thickening of the bladder wall (n = 6), ureteral dilatation (n = 3) and grade I hydronephrosis (n = 1). No malignant lesions, hepatic lesions nor hepatobiliary related disorders were found. After treatment, the S. haematobium global score (5 vs 3.4, p = 0.06) and the urinary bladder score (2 vs 1, p = 0.059) showed a trend towards improvement after treatment. In three patients the score after treatment dropped to 0, and in another three it remained the same although with signs of improvement. No worsening of the score was observed in any case.

CONCLUSION

For those patients with a diagnosis of schistosomiasis based solely in a positive serology, the ultrasound examination could safely be spared due to the low prevalence of pathological findings and its response to treatment anyway.

Parasitic infections of the spine: case series and review of the literature

OBJECTIVEAlthough parasitic infections are endemic to parts of the developing world and are more common in areas with developing economies and poor sanitary conditions, rare cases may occur in developed regions of the world.METHODSArticles eligible for the authors' literature review were initially searched using PubMed with the phrases "parasitic infections" and "spine." After the authors developed a list of parasites associated with spinal cord infections from the initial search, they expanded it to include individual diagnoses, using search terms including "neurocysticercosis," "schistosomiasis," "echinococcosis," and "toxoplasmosis."RESULTSTwo recent cases of parasitic spinal infections from the authors' institution are included.CONCLUSIONSKey findings on imaging modalities, laboratory studies suggestive of parasitic infection, and most importantly a thorough patient history are required to correctly diagnose parasitic spinal infections.

Massive Bilateral Hydroureteronephrosis and End-Stage Renal Disease Ensuing From Chronic Schistosomiasis: A Case Report

Globally, schistosomal infections affect over 200 million people resulting in the loss of 70 million disability-adjusted life years. In the sub-Saharan Africa region, where over 85% of the global schistosomal infections are found, it is estimated that about 120 million people become symptomatic, over 20 million have severe disease, and nearly 200 000 die every year. Renal impairment is a severe consequence of schistosomiasis occurring in about 6% of all infected individuals and in 15% of those with the hepatosplenic form. We present a case of massive bilateral hydroureteronephrosis and end-stage renal disease resulting from chronic schistosomiasis in a 38-year-old male of African origin. A 38-year-old male rice farmer of African origin presented with a history of elevated blood pressure, abdominal swelling, and reduced urinary output for about 10 months. Abdominal examination revealed an intraabdominal mass measuring 30 cm × 17 cm extending from the right hypochrondrium region downward to right inguinal outward to umbilicus crossing the midline. He had an estimated glomerular filtration rate of 3.9 mL/min, hemoglobin of 6.78 g/dL, and had multiple electrolyte abnormalities. A computed tomography intravenous urogram scan of the abdomen revealed hepatomegaly (18 cm), bilateral renal enlargement with hydroureteronephrosis, and multiple calcifications on the urinary bladder. A rectal biopsy isolated haematobium eggs and confirmed the diagnosis. Urinary schistosomiasis can have distressing effects on the urinary system in particular and survival prospects in general. In view of this, extensive evaluation of the genitourinary system is pivotal for timely diagnosis and prompt management particularly in residents of schistosoma-endemic communities presenting with obstructive uropathy.

Analysis of CT characteristics in the diagnosis of Schistosoma japonicum associated appendicitis with clinical and pathological correlation: a diagnostic accuracy study

PURPOSE

To clarify unique non-contrast CT (NCCT) characteristics for early recognition of Schistosomal associated appendicitis (SAA) differentiating from Non-schistosomal associated appendicitis (NSA).

MATERIAL AND METHODS

Clinical and pathological data of 50 cases with SAA and 60 cases with NSA who underwent emergency appendectomy were retrospectively compared to pre-surgical NCCT features such as direct and indirect signs of acute appendicitis as well as appendicoliths, colon calcifications as diagnostic criteria. Statistical methods such as Chi-square (χ²), t-tests, Principal component analysis (PCA), Binary Logistic regression (LR) and Factor Analysis (FA) were utilized to observe differences and isolate recognizable CT features of SAA. Pre and post hoc diagnostic performance of all criteria was calculated as sensitivity, specificity, and the Odds Ratio (OR).

RESULTS

Age > 50 years, diameter > 13 mm, pneumatosis, peri appendiceal abscess, focal wall defect, perforation; Orbital, linear and point types of appendicular wall calcifications; sigmoid colon and cecal curvilinear calcifications were observed as unique characteristics with a sensitivity of 84-95% and specificity of 91-98% in predicting SAA by OR of 6.2 times. Pre and post hoc hypothetical analysis did not show any significance for all other factors.

CONCLUSION

Factors such as elderly age, CT features such as larger appendicular diameter, appendicular wall calcifications along with sigmoid colon, and cecal calcifications, signs of perforation or abscess are characteristic for early recognition of SAA.

Jejunal Ulcer Caused by Schistosoma japonicum

Intestinal schistosomiasis can be caused by the trematodes Schistosoma japonicum that mainly exists in East Asia or the S. mansoni in Africa and South America. The adult worms of S. japonicum live in the mesenteric veins and excrete eggs that circulate to the liver and colon; the eggs migrate through the intestinal wall and pass out with the stool. Here, we report a case of jejunal ulcer caused by the infection of Schistosoma japonicum. A 63-year-old woman from Wuhan, China, was admitted with left quadrant abdominal pain and weight loss for more than 6 months. The patient's computerized tomography reported cirrhotic liver changes, jejunal wall edema, and narrowed lumen; the upper enteroscopy corroborated these findings with the presence of several jejunal ulcers and edema. The pathology report showed chronic inflammation with ulcerative changes and S. japonicum eggs deposition. Schistosomiasis is one of the neglected tropical diseases that affect the poorest. Although a great improvement has been made to control it, there is a lot of work that remains to be fulfilled.

Spirorchiidiasis in marine turtles: the current state of knowledge

Blood flukes of the family Spirorchiidae are important disease agents in marine turtles. The family is near cosmopolitan in distribution. Twenty-nine marine species across 10 genera are currently recognized, but taxonomic problems remain and it is likely that more species will be discovered. Spirorchiids infect the circulatory system, where they and their eggs cause a range of inflammatory lesions. Infection is sometimes implicated in the death of the turtle. In some regions, prevalence in stranded turtles is close to 100%. Knowledge of life cycles, important for control and epidemiological studies, has proven elusive until recently, when the first intermediate host identifications were made. Recent molecular studies of eggs and adult worms indicate that a considerable level of intrageneric and intraspecific diversity exists. The characterization of this diversity is likely to be of importance in exploring parasite taxonomy and ecology, unravelling life cycles, identifying the differential pathogenicity of genotypes and species, and developing antemortem diagnostic tools, all of which are major priorities for future spirorchiid research. Diagnosis to date has been reliant on copromicroscopy or necropsy, which both have significant limitations. The current lack of reliable antemortem diagnostic options is a roadblock to determining the true prevalence and epidemiology of spirorchiidiasis and the development of effective treatment regimes.

Schistosomiasis: Drugs used and treatment strategies

Neglected tropical diseases (NTDs) affect millions of people in different geographic regions, especially the poorest and most vulnerable. Currently NTDs are prevalent in 149 countries, seventeen of these neglected tropical parasitic diseases are classified as endemic. One of the most important of these diseases is schistosomiasis, also known as bilharzia, a disease caused by the genus Schistosoma. It presents several species, such as Schistosoma haematobium, Schistosoma japonicum and Schistosoma mansoni, the latter being responsible for parasitosis in Brazil. Contamination occurs through exposure to contaminated water in the endemic region. This parasitosis is characterized by being initially asymptomatic, but it is able to evolve into more severe clinical forms, potentially causing death. Globally, more than 200 million people are infected with one of three Schistosome species, including an estimated 40 million women of reproductive age. In Brazil, about 12 million children require preventive chemotherapy with anthelmintic. However, according to the World Health Organization (WHO), only about 15% of the at-risk children receive regular treatment. The lack of investment by the pharmaceutical industry for the development and/or improvement of new pharmaceutical forms, mainly aimed at the pediatric public, is a great challenge. Currently, the main forms of treatment used for schistosomiasis are praziquantel (PZQ) and oxaminiquine (OXA). PZQ is the drug of choice because it presents as a high-spectrum anthelmintic, used in the treatment of all known species of schistosomiasis and some species of cestodes and trematodes. OXA, however, is not active against the three Schistosome species. This work presents a literature review regarding schistosomiasis. It addresses points such as available treatments, the role of the pharmaceutical industry against neglected diseases, and perspectives for treatment.

Diagnosis of coinfection by schistosomiasis and viral hepatitis B or C using 1H NMR-based metabonomics

BACKGROUND

Diagnosis of liver involvement due to schistosomiasis in asymptomatic patients from endemic areas previously diagnosed with chronic hepatitis B (HBV) or C (HCV) and periportal fibrosis is challenging. H-1 Nuclear Magnetic Resonance (NMR)-based metabonomics strategy is a powerful tool for providing a profile of endogenous metabolites of low molecular weight in biofluids in a non-invasive way. The aim of this study was to diagnose periportal fibrosis due to schistosomiasis mansoni in patients with chronic HBV or HCV infection through NMR-based metabonomics models.

METHODOLOGY/PRINCIPAL FINDINGS

The study included 40 patients divided into two groups: (i) 18 coinfected patients with schistosomiasis mansoni and HBV or HCV; and (ii) 22 HBV or HCV monoinfected patients. The serum samples were analyzed through H-1 NMR spectroscopy and the models were based on Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA). Ultrasonography examination was used to ascertain the diagnosis of periportal fibrosis. Exploratory analysis showed a clear separation between coinfected and monoinfected samples. The supervised model built from PLS-DA showed accuracy, R2 and Q2 values equal to 100%, 98.1% and 97.5%, respectively. According to the variable importance in the projection plot, lactate serum levels were higher in the coinfected group, while the signals attributed to HDL serum cholesterol were more intense in the monoinfected group.

CONCLUSIONS/SIGNIFICANCE

The metabonomics models constructed in this study are promising as an alternative tool for diagnosis of periportal fibrosis by schistosomiasis in patients with chronic HBV or HCV infection from endemic areas for Schistosoma mansoni.