A systematic review of the frequency of neurocyticercosis with a focus on people with epilepsy

Diagnosis of Taenia solium infections based on "mail order" RNA-sequencing of single tapeworm egg isolates from stool samples

Combined community health programs aiming at health education, preventive anti-parasitic chemotherapy, and vaccination of pigs have proven their potential to regionally reduce and even eliminate Taenia solium infections that are associated with a high risk of neurological disease through ingestion of T. solium eggs. Yet it remains challenging to target T. solium endemic regions precisely or to make exact diagnoses in individual patients. One major reason is that the widely available stool microscopy may identify Taenia ssp. eggs in stool samples as such, but fails to distinguish between invasive (T. solium) and less invasive Taenia (T. saginata, T. asiatica, and T. hydatigena) species. The identification of Taenia ssp. eggs in routine stool samples often prompts a time-consuming and frequently unsuccessful epidemiologic workup in remote villages far away from a diagnostic laboratory. Here we present "mail order" single egg RNA-sequencing, a new method allowing the identification of the exact Taenia ssp. based on a few eggs found in routine diagnostic stool samples. We provide first T. solium transcriptome data, which show extremely high mitochondrial DNA (mtDNA) transcript counts that can be used for subspecies classification. "Mail order" RNA-sequencing can be administered by health personnel equipped with basic laboratory tools such as a microscope, a Bunsen burner, and access to an international post office for shipment of samples to a next generation sequencing facility. Our suggested workflow combines traditional stool microscopy, RNA-extraction from single Taenia eggs with mitochondrial RNA-sequencing, followed by bioinformatic processing with a basic laptop computer. The workflow could help to better target preventive healthcare measures and improve diagnostic specificity in individual patients based on incidental findings of Taenia ssp. eggs in diagnostic laboratories with limited resources.

Spatial distribution and risk factors for human cysticercosis in Colombia

Background

Cysticercosis is a zoonotic neglected tropical disease (NTD) that affects humans and pigs following the ingestion of Taenia solium eggs. Human cysticercosis poses a substantial public health burden in endemic countries. The World Health Organization (WHO) aims to target high-endemicity settings with enhanced interventions in 17 countries by 2030. Between 2008 and 2010, Colombia undertook a national baseline serosurvey of unprecedented scale, which led to an estimated seroprevalence of T. solium cysticercus antibodies among the general population of 8.6%. Here, we use contemporary geostatistical approaches to analyse this unique dataset with the aim of understanding the spatial distribution and risk factors associated with human cysticercosis in Colombia to inform how best to target intervention strategies.

Methods

We used a geostatistical model to estimate individual and household risk factors associated with seropositivity to T. solium cysticercus antibodies from 29,253 people from 133 municipalities in Colombia. We used both independent and spatially structured random effects at neighbourhood/village and municipality levels to account for potential clustering of exposure to T. solium. We present estimates of the distribution and residual correlation of seropositivity at the municipality level.

Results

High seroprevalence was identified in municipalities located in the north and south of Colombia, with spatial correlation in seropositivity estimated up to approximately 140 km. Statistically significant risk factors associated with seropositivity to T. solium cysticercus were related to age, sex, educational level, socioeconomic status, use of rainwater, consumption of partially cooked/raw pork meat and possession of dogs.

Conclusions

In Colombia, the distribution of human cysticercosis is influenced by socioeconomic considerations, education and environmental factors related to the spread of T. solium eggs. This information can be used to tailor national intervention strategies, such as targeting spatial hotspots and more highly exposed groups, including displaced people and women. Large-scale seroprevalence surveys accompanied by geospatial mapping are an essential step towards reaching the WHO’s 2021‒2030 NTD roadmap targets.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-05092-8.

Validating efficacy of Sericocomopsis hildebrandtii, Carissa edulis, and Ximenia americana in treating Taenia solium cysticercosis in pigs: A randomized controlled trial

Ethnoveterinary use of plants dates back to ancient times. This study aimed to validate purported efficacy of Sericocomopsis hildebrandtii and a concoction of Carissa edulis and Ximenia americana in treating Taenia solium cysticercosis in pigs. Twenty-four infected pigs were randomly allocated to T1, T2, and T0 groups, each with eight pigs. Each T1 pig was provided with 8 g of S. hildebrandtii root powder, whereas each T2 pig was given 8 g of the concoction. T0 was a control. The pigs were slaughtered 16 weeks post treatment and carcase dissections were performed to establish cyst numbers. T1 cyst numbers were significantly lower than those of T0 (p = .004) and T2 (p = .013). No difference was observed between T2 and T0. This study validated efficacy of S. hildebrandtii but not of X. americana and C. edulis. Further studies are necessary for validation and documentation of plants of ethnoveterinary importance.

My experience on taeniasis and neurocysticercosis

Taeniasis and neurocysticercosis (NCC) are major public health problems in developing countries. NCC is the leading cause of community-acquired active epilepsy. NCC may present as a medical emergency, especially when there is cysticercotic encephalitis or raised intracranial hypertension. Systematic community-based studies on taeniasis and NCC are lacking. We studied taeniasis and NCC-related active epilepsy disease burden in the pig farming community of Lucknow district, Uttar Pradesh, India. Based on the 30 cluster sampling approach as recommended by the World Health Organization, we estimated the prevalence of taeniasis, NCC-related active epilepsy, and silent NCC in the community. We also estimated the prevalence of swine cysticercosis. Taeniasis was detected in 18.6% of populations. Expulsions of tapeworm segments in stool, consumption of undercooked pork, age above 15 years, and handwash with clay or plain water after defecation were associated with taeniasis. On molecular analyses of positive stool samples, T. solium was identified in 40% and Taenia asiatica in 60% of cases. Active epilepsy was identified in 5.8% of subjects; 48% of them had NCC. On neuroimaging, NCC was detected in 15% of asymptomatic individuals. We observed that host genetic factors such as toll-like receptor-4, matrix metalloproteinase-9, intercellular adhesion molecule-1, and glutathione-S transferase gene polymorphisms were associated with seizure in NCC. When peripheral blood mononuclear cells (PBMCs) from NCC subjects were exposed to cysticerci fluid antigens in-vitro, PBMCs from symptomatic and asymptomatic subjects showed significantly higher Th 1 and Th 2 cytokines response respectively, symptomatic patients had significant Th-1 cytokines response, while asymptomatic individuals showed Th-2 response. Porcine cysticercosis was detected in 26% of swine; 38% of them had cysticerci in the brain. Swine with brain involvement showed clinical signs such as excessive salivation, excessive blinking and tearing, and subconjunctival nodule. On molecular analysis, 15% of cysticerci in swine were identified as T. asiatica. Infected swine when treated with albendazole plus/minus steroid, the response rate of cysticerci (either dead or resolved lesion) was 100% in albendazole-treated group and 71% in albendazole plus steroid-treated group. The above studies suggest that taeniasis and NCC are alarmingly high in the pig farming community of North India. Taeniasis in human and cysticercosis in swine due to T. asiatica call for further studies on this parasite.

Hyperendemicity of cysticercosis in Madagascar: Novel insights from school children population-based antigen prevalence study

Objective

Taenia solium (Ts) cysticercosis is a neglected zoonotic disease particularly prevalent in Madagascar. Few data are available for children, current data mainly rely on antibody prevalence. We sought to determine the Ts-antigen seroprevalence–determining active cysticercosis—amongst school children from various cities in Madagascar (excluding the capital) and evaluated associated risk factors.

Methods

In seven cities in Madagascar, the presence of cysticercosis in school children (n = 1751) was investigated in 2007 using the B158/B60 antigen (Ag)-ELISA.

Results

The overall prevalence based on Ag detection was 27.7% [95%CI: 10–37%]. Risk factors associated with Ag positivity were age, biotope, altitude and annual average rainfall.

Conclusion

These results highlight the high prevalence of active cysticercosis in Madagascar among school children in an urban setting. This high prevalence as well as the risk factors unraveled point to the emergency to implement appropriate Public Health measure son a national scale.

Neurocysticercosis and HIV/AIDS co-infection: A scoping review

OBJECTIVES

Neurocysticercosis (NCC) and human immunodeficiency virus (HIV) have a high disease burden and are prevalent in overlapping low- and middle-income areas. Yet, treatment guidance for people living with HIV/AIDS (PLWH/A) co-infected with NCC is currently lacking. This study aims to scope the available literature on HIV/AIDS and NCC co-infection, focusing on epidemiology, clinical characteristics, diagnostics and treatment outcomes.

METHODS

The scoping literature review methodological framework, and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. A total of 16,969 records identified through database searching, and 45 additional records from other sources were reduced to 52 included studies after a standardised selection process.

RESULTS

Two experimental studies, ten observational studies, 23 case series/case reports and 17 reviews or letters were identified. Observational studies demonstrated similar NCC seroprevalence in PLWH/A and their HIV-negative counterparts. Of 29 PLWH/A and NCC co-infection, 17 (59%) suffered from epileptic seizures, 15 (52%) from headaches and 15 (52%) had focal neurological deficits. Eighteen (62%) had viable vesicular cysts, and six (21%) had calcified cysts. Fifteen (52%) were treated with albendazole, of which 11 (73%) responded well to treatment. Five individuals potentially demonstrated an immune-reconstitution inflammatory syndrome after commencing antiretroviral therapy, although this was in the absence of immunological and neuroimaging confirmation.

CONCLUSIONS

There is a paucity of evidence to guide treatment of PLWH/A and NCC co-infection. There is a pressing need for high-quality studies in this patient group to appropriately inform diagnostic and management guidelines for HIV-positive patients with NCC.

Subarachnoid Neurocysticercosis Presenting as a New-Onset Seizure in an Immigrant From Guatemala

Subarachnoid involvement is a rare but severe form of neurocysticercosis (NCC), leading to serious complications if not recognized and treated appropriately. Imaging of the brain usually involves computed tomography and/or magnetic resonance image (MRI) of the brain, both of which can lead to a diagnosis of NCC. We present a 20-year-old female with no significant past medical history presenting with a new-onset seizure whose clinical treatment was significantly altered when subarachnoid involvement was identified. This case highlights the importance of brain MRI in recognizing subarachnoid disease, an important subset of NCC disease presentation.

Vaccine for a neglected tropical disease Taenia solium cysticercosis: fight for eradication against all odds

INTRODUCTION

Taenia solium infection is among the 17 most neglected tropical diseases identified by World Health Organization and to be eradicated by 2030. This parasite infects the central nervous system (Neurocysticercosis [NCC]) and intestine [Taeniasis]). NCC is the most frequent cause of acquired epilepsy in endemic regions and Taeniasis is responsible for the widespread malnutrition and abdominal discomfort among children. Epilepsy caused by T. solium is preventable and the total elimination of NCC can be achieved by good hygiene, mass therapy, and most importantly vaccination of pigs or humans. Vaccine for pig is available but not widely in use and for humans it's still elusive.

AREA COVERED

Several vaccine candidates for porcine cysticercosis have been tried like TSOL18, SP3Vac, KETc7, TSOL45, etc. with good success in the limited field trial. This review highlights some seminal contributions for the anti-cestode vaccine, the associated challenges, current status, suggestive future directions, and the need of vaccine for human use.

EXPERT OPINION

Though several vaccines are available, none is being widely used due to lack of awareness, economic constraints, accessibility, etc. Hence, there is a need for a newer, economic, and reliable vaccine for humans or pigs use to reduce the disease burden.

The returned traveler with neurologic manifestations: could my patient have a parasite?

PURPOSE OF REVIEW

The present review focuses on parasitic infections of the central nervous system (CNS) that can affect the international traveler.

RECENT FINDINGS

The epidemiology of imported parasitic infections is changing and clinicians are treating increasing numbers of returned travelers with parasitic infections in the CNS with which they are not familiar.

SUMMARY

The epidemiology, life cycle, clinical manifestations, diagnosis, and treatment of parasites that affect the CNS will be discussed.

Geographically Targeted Interventions versus Mass Drug Administration to Control Taenia solium Cysticercosis, Peru

Optimal control strategies for Taenia solium taeniasis and cysticercosis have not been determined. We conducted a 2-year cluster randomized trial in Peru by assigning 23 villages to 1 of 3 geographically targeted intervention approaches. For ring screening (RS), participants living near pigs with cysticercosis were screened for taeniasis; identified cases were treated with niclosamide. In ring treatment (RT), participants living near pigs with cysticercosis received presumptive treatment with niclosamide. In mass treatment (MT), participants received niclosamide treatment every 6 months regardless of location. In each approach, half the villages received targeted or mass oxfendazole for pigs (6 total study arms). We noted significant reductions in seroincidence among pigs in all approaches (67.1% decrease in RS, 69.3% in RT, 64.7% in MT; p<0.001), despite a smaller proportion of population treated by targeted approaches (RS 1.4%, RT 19.3%, MT 88.5%). Our findings suggest multiple approaches can achieve rapid control of T. solium transmission.

Quantitative risk assessment of human Taenia solium exposure from consuming pork produced in Punjab, India

Taenia solium cysticercosis is a neglected zoonosis that affects people throughout much of the developing world. The disease is endemic in Punjab state of India and controlling it is a public health challenge. No studies have been conducted to quantify the risk of T. solium exposure from consuming pork produced in the state. A stochastic quantitative risk assessment (QRA) model was constructed to understand the risk of human T. solium infection from consuming pork produced in Punjab. Input data were collected from official records, published literature, active surveillance and specifically for this study. Sensitivity analyses were conducted to assess the influence of the input parameters on the main output probability that any one pork meal is infective (contains at least one viable cyst) at consumption. The probability of any pork meal in Punjab containing at least one viable T. solium cyst post-storage and post-cooking was median 5.57 × 10^-4 (95% PI 1.06 × 10^-4 -1.95 × 10^-3 ). Sobol' sensitivity analysis demonstrated that the most influential input parameters on consumption of a pork meal with at least one viable T. solium were the probability that a meal is insufficiently cooked to render cysts unviable, and the proportion of infected carcasses following informal slaughter. Whilst improved sanitation and hygiene can prevent cysticercosis in people, efforts to reduce the prevalence of T. solium cysts in pig carcases by preventing pigs' access to human waste, increasing meat inspection and promoting effective cooking practices are also important to reduce this source of taeniasis.

Neurocysticercosis. A frequent cause of seizures, epilepsy, and other neurological morbidity in most of the world

Neurocysticercosis is endemic in most of the world and in endemic areas it accounts for approximately 30% of cases of epilepsy. Appropriate diagnosis and management of neurocysticercosis requires understanding the diverse presentations of the disease since these will vary in regards to clinical manifestation, sensitivity of diagnostic tests, and most importantly, therapeutic approach. This review attempts to familiarize tropical neurology practitioners with the diverse types of neurocysticercosis and the more appropriate management approaches for each.

Parasitic Infections of the Nervous System

PURPOSE OF REVIEW

This article reviews how parasites affect the human nervous system, with a focus on four parasitic infections of major public health importance worldwide, two caused by protozoa (malaria and toxoplasmosis) and two by helminths (neurocysticercosis and schistosomiasis).

RECENT FINDINGS

Parasitic infections in humans are common, and many can affect the central nervous system where they may survive unnoticed or may cause significant pathology that can even lead to the death of the host. Neuroparasitoses should be considered in the differential diagnosis of neurologic lesions, particularly in individuals from endemic regions or those with a history of travel to endemic regions.

SUMMARY

Cerebral malaria is a significant cause of mortality, particularly in African children, in whom infected red blood cells affect the cerebral vessels, causing severe encephalopathy. Neurocysticercosis is the most common cause of acquired epilepsy worldwide and has varied clinical presentations, depending on the number, size, and location of the parasites in the nervous system as well as on the host's inflammatory response. Toxoplasmosis is distributed worldwide, affecting a significant proportion of the population, and may reactivate in patients who are immunosuppressed, causing encephalitis and focal abscesses. Schistosomiasis causes granulomatous lesions in the brain or the spinal cord.

Chronic administration of cryptolepine nanoparticle formulation alleviates seizures in a neurocysticercosis model

Worldwide, neurocysticercosis remains an important cause of acquired epilepsy. We therefore seek to investigate the effectiveness of the nanoparticle formulation of cryptolepine in alleviating seizures in a neurocysticercosis model. A solid-lipid nanoparticle formulation of extracted cryptolepine was prepared. The parasites were maintained in T. crassiceps metacestode (ORF strain) - infected female BALB/c mice. Cryp (5 ​mg/kg), SLN-CRYP (5 ​mg/kg), ABZ (50 ​mg/kg) DXM (0.5 ​mg/kg), and PHE (30 ​mg/kg). were assessed for in vitro cysticidal, in vivo cysticidal and/or antiseizure activity in 70 mice that had developed seizures from infection with T. crassiceps. General pathologic processes were studied in the host tissue and inflammatory mediators were quantified from isolated mice brains. All treatments (CRYP, SLN-CRYP and ABZ) caused significantly reduced viability of T. crassiceps cysts. Treatment with SLN-CRYP significantly shrunk cysticerci and resolved ventricular expansion and deviation similar to albendazole on examination of encephala. SLN-CRYP inhibited hyperemia but was more effective against microgliosis, calcification, edema and meningitis. Mean seizure score was significantly reduced in models administered with SLN-CRYP (p ​< ​0.0001); as were frequency (p ​< ​0.0001) and duration (p ​< ​0.0001) of seizures. SLN-CRYP significantly reduced brain homogenate levels of IL-10 (p ​= ​0.0016) and IFN-γ (p ​< ​0.0001). Our study shows that the chronic administration of the nanoparticle formulation of cryptolepine is effective in alleviating seizures associated with neurocysticercosis in a mouse model.

Brain calcification because of neurocysticercosis: a vast field to be explored

PURPOSE OF REVIEW

Neurocysticercosis is the most common helminthic infection of the central nervous system caused by the larval stage of the pork tapeworm, Taenia solium. Endemic regions include Latin American countries, sub-Saharan Africa, and large regions of Asia, including the Indian subcontinent and is a global health problem. Seizures are the most common manifestation and approximately 30% of adult-onset seizures in endemic regions are attributable to NCC. Calcifications because of neurocysticercosis is the most common finding on imaging in endemic regions and are important seizure foci contributing to the burden of epilepsy.

RECENT FINDINGS

After treatment with antiparasitics for multiple viable parenchymal disease, approximately 38% of cysts that resolved after 6 months of therapy will result in residual calcifications, which represents a significant burden of residual disease. Calcified disease has been referred to as 'inactive disease', but there is accumulating evidence to suggest that calcified granulomas are actually dynamic and substantially contribute to the development and maintenance of seizures.

SUMMARY

Calcified parenchymal neurocysticercosis contributes significantly to the development and maintenance of seizures in endemic regions. Understanding the pathogenesis of the role of calcified NCC in seizure development and risk factors for development of calcifications after treatment is critical to decreasing the burden of symptomatic disease in endemic regions.

Neurocysticercosis: Current Perspectives on Diagnosis and Management

Porcine cysticercosis, human taeniasis, and (neuro)cysticercosis are endemic in many low- and middle-income countries (LMIC) where they present a significant health burden to affected communities. Neurocysticercosis (NCC) is one of the leading causes of human epilepsy in many hyperendemic regions in Latin America, Asia, and sub-Saharan Africa. The World Health Organization (WHO) reports an estimated 2.5-8.3 million cases of NCC annually with a disability-adjusted life year (DALY) burden of 2.8 million, but as for all neglected tropical diseases (NTDs), these values are likely to be underestimated. Diagnosis of NCC is complex and most accurately diagnosed using clinical neuroimaging that is unavailable in most hyperendemic regions in LMIC. On January 28, 2021, WHO will launch its road map for the NTDs' "Ending the neglect to attain the Sustainable Development Goals: a road map for neglected tropical diseases 2021-2030." Taeniasis/cysticercosis is targeted for control success considered as steady increase in the number of countries with intensified control in hyperendemic areas [increasing from 2 (3%) in 2020 to 4 (6%) in 2023, to 9 (14%) by 2025, and to 17 (27%) by 2030]. Cross-cutting targets that include 100% access to at least basic water supply, sanitation, and hygiene in areas endemic for NTDs and 75% integrated treatment coverage for preventative chemotherapy will additionally impact on the taeniasis/cysticercosis/NCC complex. With no vaccine available for humans, prevention of infection depends on communication to the public of the life cycle of a complex zoonosis to promote behavior change, underpinned by practical control measures including treatment of human taeniasis and (neuro)cysticercosis with albendazole and praziquantel [widely used as part of the mass drug administration (MDA) deworming programs], surgery where appropriate, and effective vaccination and deworming for pigs supported by meat inspection. Here, we review recent advances in tools and implementation for Taenia solium taeniasis/(neuro)cysticercosis (TSTC) control and milestones on the onward path to elimination.

Changes in inflammatory gene expression in brain tissue adjacent and distant to a viable cyst in a rat model for neurocysticercosis

BACKGROUND

The parasite Taenia solium causes neurocysticercosis (NCC) in humans and is a common cause of adult-onset epilepsy in the developing world. Hippocampal atrophy, which occurs far from the cyst, is an emerging new complication of NCC. Evaluation of molecular pathways in brain regions close to and distant from the cyst could offer insight into this pathology.

METHODS

Rats were inoculated intracranially with T. solium oncospheres. After 4 months, RNA was extracted from brain tissue samples in rats with NCC and uninfected controls, and cDNA was generated. Expression of 38 genes related to different molecular pathways involved in the inflammatory response and healing was assessed by RT-PCR array.

RESULTS

Inflammatory cytokines IFN-γ, TNF-α, and IL-1, together with TGF-β and ARG-1, were overexpressed in tissue close to the parasite compared to non-infected tissue. Genes for IL-1A, CSF-1, FN-1, COL-3A1, and MMP-2 were overexpressed in contralateral tissue compared to non-infected tissue.

CONCLUSIONS

The viable cysticerci in the rat model for NCC is characterized by increased expression of genes associated with a proinflammatory response and fibrosis-related proteins, which may mediate the chronic state of infection. These pathways appear to influence regions far from the cyst, which may explain the emerging association between NCC and hippocampal atrophy.

High frequency of Taenia solium antigen positivity in patients admitted for neurological disorders in the Rural Hospital of Mosango, Democratic Republic of Congo

Background

The epidemiology of human cysticercosis and neurocysticercosis, caused by the larval stage of the pork tapeworm Taenia solium, is not well known in the Democratic Republic of Congo (DRC). Within a multicenter etiological and diagnostic study conducted by the NIDIAG consortium (“Better Diagnosis for Neglected Infections”) and investigating several challenging syndromes, we consecutively evaluated from 2012 to 2015 all patients older than 5 years presenting with neurological disorders (neurology cohort) and with fever > 7 days (persistent fever cohort) at the rural hospital of Mosango, province of Kwilu, DRC. In both cohorts, etiological diagnosis relied on a systematic set of reference laboratory assays and on pre-established clinical case definitions. No neuroimaging was available in the study hospital. In this study, we determined the frequency of T. solium infection in both cohorts and explored in the neurology cohort its association with specific neurological presentations and final etiological diagnoses.

Methods

We conducted a post-hoc descriptive and analytic study on cysticercosis in the neurology and persistent fever cohorts, based on the presence in serum samples of circulating T. solium antigen using the B158/B60 enzyme-linked immunosorbent assay (ELISA) and of cysticercosis IgG using the LDBIO Cysticercosis Western Blot IgG assay.

Results

For the neurology cohort, 340 samples (of 351 enrolled patients) were available for analysis (males: 46.8%; mean age: 38.9 years). T. solium antigen positivity was found in 43 participants (12.6%; 95% confidence interval [CI] 9.3–16.7%), including 9 of 60 (15%) patients with epilepsy. Among the 148 samples available from the persistent fever cohort (males: 39.9%; mean age: 19.9 years), 7 were positive in the T. solium antigen ELISA (4.7%; 95% CI 1.9–9.5%; P = 0.009 when compared to the neurology cohort). No significant association was found within the neurology cohort between positivity and clinical presentation or final diagnoses. Of note, the IgG antibody-detecting assay was found positive in only four (1.3%) of the participants of the neurology cohort and in none of the persistent fever cohort.

Conclusions

T. solium antigen positivity was found in at least 10% of patients admitted with neurological disorders in the Kwilu province, DRC, with no specific pattern of presentation. Further neuroimaging studies should be used to confirm whether neurocysticercosis is prevalent in this region.

Meat-borne parasites in the Arab world: a review in a One Health perspective

Meat-borne parasitic zoonoses are generally not well-monitored, and so understanding extent and overall prevalence is problematic. Without sufficient attention, their prevalence can become unexpectedly and unacceptably high. This review sheds light on meat-borne parasites in the Arab world, which includes all the Arab countries situated in the continents of Asia and Africa, with more than 400 million inhabitants distributed in 22 countries. Meat-borne parasites can be divided into two main categories-helminths and protozoa. The main helminths included in this review are Taenia saginata, Taenia solium, Taenia asiatica, Echinococcus spp., Fasciola spp., and Trichinella spiralis, while the meat-borne protozoan parasites are Toxoplasma gondii, Cryptosporidium spp., and Sarcocystis spp. In addition, Linguatula serrata, which belongs to the class Pentastomida, was included. Among those, the genus Taenia is the most frequently reported in the Arab world, particularly T. saginata. Many parasitic infections that are mainly transmitted through pork, although widespread in many parts of the world, are rare in the Arab countries, primarily due to religious proscriptions. The majority of the publications concerning meat-borne parasites were from Egypt, which contains the largest population in the Arab world and the highest population density, in addition to various economic, social, and environmental reasons.

Taenia solium taeniasis/cysticercosis: From parasite biology and immunology to diagnosis and control

Infection with the pork tapeworm (Taenia solium) is responsible for a substantial global burden of disease, not only restricted to its impact on human health, but also resulting in a considerable economic burden to smallholder pig farmers due to pig cysticercosis infection. The life-cycle, parasitology and immunology of T. solium are complex, involving pigs (the intermediate host, harbouring the larval metacestode stage), humans (the definitive host, harbouring the adult tapeworm, in addition to acting as accidental intermediate hosts) and the environment (the source of infection with eggs/proglottids). We review the parasitology, immunology, and epidemiology of the infection associated with each of the T. solium life-cycle stages, including the pre-adult/adult tapeworm responsible for human taeniasis; post-oncosphere and cysticercus associated with porcine and human cysticercosis, and the biological characteristics of eggs in the environment. We discuss the burden associated, in endemic settings, with neurocysticercosis (NCC) in humans, and the broader cross-sectoral economic impact associated both with NCC and porcine cysticercosis, the latter impacting food-value chains. Existing tools for diagnostics and control interventions that target different stages of the T. solium transmission cycle are reviewed and their limitations discussed. Currently, no national T. solium control programmes have been established in endemic areas, with further work required to identify optimal strategies according to epidemiological setting. There is increasing evidence suggesting that cross-sectoral interventions which target the parasite in both the human and pig host provide the most effective approaches for achieving control and ultimately elimination. We discuss future avenues for research on T. solium to support the attainment of the goals proposed in the revised World Health Organisation neglected tropical diseases roadmap for 2021-2030 adopted at the 73rd World Health Assembly in November 2020.

Peripheral Taenia infection increases immunoglobulins in the central nervous system

Human cysticercosis is a disease caused by larvae of the cestode Taenia solium. It is an important common cause of adult-onset seizures world-wide where it exacts a debilitating toll on the health and well-being of affected communities. It is commonly assumed that the major symptoms associated with cysticercosis are a result of the direct presence of larvae in the brain. As a result, the possible effects of peripherally located larvae on the central nervous system are not well understood. To address this question, we utilised the Taenia crassiceps intra-peritoneal murine model of cysticercosis, where larvae are restricted to the peritoneal cavity. In this model, previous research has observed behavioural changes in rodents but not the development of seizures. Here we used ELISAs, immunoblotting and the Evans Blue test for blood-brain barrier permeability to explore the central effects of peripheral infection of mice with T. crassiceps. We identified high levels of parasite-targeting immunoglobulins in the sera of T. crassiceps-infected mice. We show that the T. crassciceps larvae themselves also contain and release host immunoglobulins over time. Additionally, we describe, for the first known time, significantly increased levels of IgG within the hippocampi of infected mice, which are accompanied by changes in blood-brain barrier permeability. However, these T. crassiceps-induced changes were not accompanied by alterations to the levels of proinflammatory, pro-seizure cytokines in the hippocampus. These findings contribute to the understanding of systemic and neuroimmune responses in the T. crassiceps model of cysticercosis, with implications for the pathogenesis of human cysticercosis.

Neurocysticercosis Presenting With a New-Onset Seizure: A Case Report

Neurocysticercosis (NCC) is a common infection that is found worldwide but is often neglected in the United States (US). This case report aims to illustrate the presentation of the disease, provide information on this globally prevalent pathogen, and shed light on the diagnostic workup and treatment of the infection. We discuss the case of a 31-year-old male patient of Central American origin presenting with a new-onset seizure. He had no significant past medical history and had never experienced similar events before. The diagnosis was made through neuroimaging, serum antibody testing, and biopsy of the brain lesion. This case highlights the importance of performing a good clinical history and a proper diagnostic workup that would help in the prompt recognization and treatment of this common worldwide illness that may not be endemic to the clinician's geographical area.

The effectiveness of anti-inflammatory and anti-seizure medication for individuals with single enhancing lesion neurocysticercosis: A meta-analysis and expert group-based consensus recommendations

Single brain enhancing lesions (SEL) are the most common presentation of neurocysticercosis (NCC) observed on neuroimaging in people presenting with epileptic seizures not only on the Indian sub-continent and in travelers returning from cysticercosis-endemic regions, but are also present in other parts of the world. The aim of this study, which consisted of a systematic review (CRD42019087665), a meta-analysis and an expert group consultation, was to reach consensus on the best anti-seizure medication and anti-inflammatory treatment for individuals with SEL NCC. Standard literature review methods were used. The Cochrane risk of bias tool was used and random effects model meta-analyses were performed. The quality of the body of evidence was rated using GRADE tables. The expert committee included 12 gender and geographically balanced members and recommendations were reached by applying the GRADE framework for guideline development. The 1-1.5-year cumulative incidence of seizure recurrence, cyst resolution or calcification following anti-seizure medication (ASM) withdrawal was not statistically different between ASM of 6, 12 or 24 months. In contrast, in persons whose cyst calcified post treatment, longer ASM decreased seizure recurrence. The cumulative incidence ratio (CIR) 1-1.5 years after stopping ASM was 1.79 95% CI: (1.00, 3.20) for patients given 6 versus 24 months treatment. Anti-inflammatory treatment with corticosteroids in patients treated with ASM compared to patients treated with ASM only showed a statistically significant beneficial effect on seizure reduction (CIR 0.44, 95% CI 0.23, 0.85) and cyst resolution (CIR 1.37, 95%CI: 1.07, 1.75). Our results indicate that ASM in patients with SEL NCC whose cysts resolved can be withdrawn, while patients whose cysts calcified seem to benefit from prolonged anti-seizure medication. Additional corticosteroid treatment was found to have a beneficial effect both on seizure reduction and cyst resolution.

The survival and dispersal of Taenia eggs in the environment: what are the implications for transmission? A systematic review

Taenia spp. are responsible for a substantial health and economic burden in affected populations. Knowledge of the fate of the eggs of Taenia spp. in the environment and of other factors facilitating the transmission of eggs to intermediate hosts is important for the control/elimination of infections caused by Taenia spp. The aim of this systematic review was to summarize current knowledge of the factors influencing the survival and dispersal of Taenia spp. eggs in the environment. Publications retrieved from international databases were systematically reviewed. Of the 1465 papers initially identified, data were ultimately extracted from 93 papers. The results of this systematic review indicate that survival is favoured at moderate temperatures (0-20 °C). Humidity seems to affect the survival of Taenia spp. eggs more than temperature. Under field circumstances, Taenia spp. eggs have been found to survive for up to 1 year. Taenia spp. eggs are commonly found on vegetables (0.9-30%) and in soil and water samples (0-43%), with their presence posing a risk to the consumer. Invertebrates may act as transport hosts, transferring the infection to an intermediate host, but the importance of this route of transmission is still open to question. Wastewater treatment systems are not capable of entirely eliminating Taenia spp. eggs. Access to surface water and the use of sewage sludge as fertilizer on pastures are important risk factors for bovine cysticercosis. Although information on the survival and spread of Taenia spp. eggs is available, in general the data retrieved and reviewed in this article were old, focused on very specific geographical regions and may not be relevant for other areas or not specific for different Taenia spp. Furthermore, it is unknown whether egg survival differs according to Taenia sp. Future studies are necessary to identify sustainable methods to identify and inactivate parasite eggs in the environment and reduce their spread.

Origin of the pork tapeworm Taenia solium in Bali and Papua, Indonesia

Global distributions of zoonotic pathogens have been strongly affected by the history of human dispersal and domestication of livestock. The pork tapeworm Taenia solium is distributed worldwide as the cause of neurocysticercosis, one of the most serious neglected tropical diseases. T. solium has been reported in Indonesia but only endemic to restricted areas such as Bali and Papua. Previous studies indicated the distinctiveness of a mitochondrial haplotype confirmed in Papua, but only one isolate has been examined to date. In this study, genetic characterization of T. solium and pigs in Bali and Papua was conducted to clarify the distributional history of the parasite. Mitochondrial haplotype network analysis clearly showed that Indonesian T. solium comprises a unique haplogroup which was the first to diverge among Asian genotypes, indicating its single origin and the fact that it was not introduced in the recent past from other area in Asia in which it is endemic. Although phylogenetic analysis based on the mitochondrial D-loop revealed multiple origins of pigs in Bali and Papua, the majority of pigs belonged to the Pacific Clade, which is widely dispersed throughout the Island Southeast Asia (ISEA) and Oceania due to Neolithic human dispersal. Given the results of our network analysis, it is likely that the Pacific Clade pigs played a key role in the dispersal of T. solium. The data suggest that T. solium was introduced from mainland Asia into Western Indonesia, including Bali, by modern humans in the late Pleistocene, or in the early to middle Holocene along with the Pacific Clade pigs. Introduction into New Guinea most likely occurred in the late Holocene through the spread of Pacific Clade pigs. Over time, T. solium has been eradicated from most of Indonesia through the middle to modern ages owing to religious and cultural practices.

Performance of Ag-ELISA in the diagnosis of Taenia solium cysticercosis in naturally infected pigs in Tanzania

Background

Taenia solium is a zoonotic parasite responsible for neurocysticercosis—a major cause of late-onset acquired epilepsy in humans. Lack of affordable, specific and sensitive diagnostic tools hampers control of the parasite. This study assessed the performance of an antigen detection enzyme-linked immunosorbent assay (Ag-ELISA) in the diagnosis of viable T. solium cysticercosis in naturally infected slaughter-age pigs in an endemic area in Tanzania.

Methods

A total of 350 pigs were bled before they were slaughtered and their carcases examined. Serum was analyzed for circulating antigens by using a monoclonal antibody-based B158/B60 Ag-ELISA. Each carcase was examined for the presence of Taenia hydatigena cysticerci and half carcase musculature together with the whole brain, head muscles, tongue, heart and diaphragm were sliced with fine cuts (< 0.5 cm) to reveal and enumerate T. solium cysticerci. Half carcase dissection can detect at least 84% of infected pigs. Prevalence and their 95% confidence intervals (CI) were calculated in Stata 12. Sensitivity, specificity, predictive values and likelihood ratios were determined.

Results

Twenty–nine pigs (8.3%, 95% CI: 5.6–11.7%) had viable T. solium cysticerci while 11 pigs had T. hydatigena cysticerci (3.1%, 95% CI: 1.6–5.5%). No co-infection was observed. Sixty-eight pigs (19.4%, 95% CI: 15.4–20%) tested positive on Ag-ELISA; of these, 24 had T. solium cysticerci and 7 had T. hydatigena cysticerci. Sensitivity and specificity were determined to be 82.7% and 86.3%, respectively. Positive and negative predictive values were 35.2% and 98.2%, respectively. Likelihood ratios for positive and negative Ag-ELISA test results were 6.0 and 0.2, respectively. There was a significant positive correlation between the titre of circulating antigens and intensity of T. solium cysticerci (r₍₃₄₈₎ = 0.63, P < 0.001).

Conclusions

The Ag-ELISA test characteristics reported in this study indicate that the test is more reliable in ruling out T. solium cysticercosis in pigs, than in confirming it. Hence, a negative result will almost certainly indicate that a pig has no infection, but a positive result should always be interpreted with caution. Estimates of T. solium prevalence based on Ag-ELISA results should, therefore, be adjusted for test performance characteristics and occurrence of T. hydatigena.

Effects of 'The Vicious Worm' educational software on Taenia solium knowledge among key pork supply chain workers in Zambia

The neglected zoonotic cestode Taenia solium is endemic in many low- and middle-income countries, including Zambia. The parasite infects humans and pigs, inflicting high socioeconomic and disease burdens in endemic areas. Health education is regarded as an important component in T. solium control and previous studies indicate that ‘The Vicious Worm’ may be an effective T. solium health education tool for Tanzanian medical and agricultural professionals and Zambian primary school students. This study aimed to assess the effects of health education using ‘The Vicious Worm’ among Zambian pork supply chain workers, because the pork supply chain greatly influences food safety and security in Zambia. Half-day educational workshops using ‘The Vicious Worm’ and subsequent follow-up sessions were organized in the Lusaka and Katete districts of Zambia in March and April 2019. Questionnaires were administered before, after, and three weeks after the use of ‘The Vicious Worm’ to assess the program’s impact on knowledge uptake and short-term retention. Focus group discussions were conducted to assess the program’s user experience and the participants’ beliefs, attitudes, and insights. In total, 47 pork supply chain workers participated: 25 from Lusaka and 22 from Katete. Overall, knowledge about T. solium was significantly higher (p<0.001) both immediately after, and three weeks after the use of ‘The Vicious Worm’ compared to baseline knowledge. Focus group discussions indicated incipient attitudinal and behavioral change, as well as a positive reception of the software; with participants describing the software as simple, educative, and useful to share knowledge. The study results indicate that workshops using ‘The Vicious Worm’ may be effective for short-term T. solium health education among key pork supply chain workers. Follow-up studies are required to assess long-term effects, transfer of knowledge and behavioral change. However, educational interventions with ‘The Vicious Worm’ could be considered for integrated T. solium control programs in sub-Saharan Africa, especially if the educational content is further simplified and clarified.

The tapeworm Taenia solium causes epilepsy and severe headaches in humans and economic losses to smallholder farmers in endemic areas where free-roaming pigs, poor sanitation and informal animal slaughter are prevalent. Treatment of human taeniosis and interventions in pigs (vaccination and anthelmintic treatment) have been established as essential tools to achieve short-term control, but health education will be crucial to sustain long-term control. ‘The Vicious Worm’ is a specific T. solium health education tool aiming to convey simple and meaningful messages concerning disease prevention and control. Previous studies found significant knowledge increases after the use of the educational tool in Tanzanian medical and agricultural professionals, and Zambian primary school students. We organized half-day educational workshops using ‘The Vicious Worm’ for pork supply chain workers at two study sites in Zambia, with follow-up visits three weeks later. We found a significant increase in participants’ knowledge, both immediately and three weeks after the health education. Furthermore, the program was well received and potentially led to attitudinal and behavioral change that could deter the propagation of T. solium. We conclude that ‘The Vicious Worm’ educational interventions may contribute to a safer pork supply chain and we encourage its implementation in future T. solium control strategies.

A prospective cohort study to assess the frequency and risk factors for calcification in single lesion parenchymal neurocysticercosis

BACKGROUND

Calcified neurocysticercosis (NCC) predisposes patients to an enduring state of epilepsy. The predictors for calcification in parenchymal neurocysticercosis are not well defined.

METHOD

In this prospective cohort study, consecutive children with single-lesion parenchymal NCC were enrolled and followed up for one year. All patients were investigated with brain 3 T-MRI and electroimmunotransfer blot (EITB). Clinical follow-ups were performed every 3 months. Radiology was repeated at the 6-month and one-year follow-ups. The proportion of calcified lesions at one year and the predictors of calcification were studied.

RESULT

During the study period from June 2013 to December 2015, 93 children with single lesion parenchymal NCC were enrolled. At presentation, 90 % of the lesions were in the colloidal stage, and 71 % of the lesions had moderate to severe perilesional oedema. All children had 6 months of follow-up, and 86 (92.5 %) had one year of follow-up. Seizure recurrence was present in 13 (14 %) children. Follow-up radiology at one year showed lesion resolution in 51 (59 %) lesions and calcification in 28 (32.5 %) lesions. Children with calcified lesions during follow-up had a higher odds of seizure recurrences {OR, 95 % CI 3.6(2.3-5.6)}. The presence at baseline of diffusion restriction {OR, 95% CI 2.9 (1.01-8.8)}, scolex or wall calcification in the T2 Star weighted angiography MRI images {OR, 95% CI 3.7 (1.7-8.2)} and >10 mm size of the lesion {OR, 95 % CI 2.4 (1.2-5.01)} predicted lesion calcification.

CONCLUSION

Children with calcification of the parenchymal NCC lesions have a higher risk for seizure recurrence during follow-up. The presence of diffusion restriction, calcified nidus in the colloidal nodular stage, and >10 mm size of the lesion at baseline predicted calcification of the lesion during follow-up.

TSOL18 vaccine and oxfendazole for control of Taenia solium cysticercosis in pigs: A field trial in endemic areas of Tanzania

A field trial was conducted in Tanzania to determine the effectiveness of TSOL18 vaccine used concurrently with oxfendazole (OFZ), and of OFZ alone, on T. solium cysticercosis determined by organ and half carcase dissection of slaughter age pigs. This study followed a quasi-experimental group design. Suitable trial sites were randomly allocated to either treatment group T1 (OFZ treatment alone [30mg/kg, Paranthic 10%]) or T2 (TSOL18 [1ml, Cysvax] plus OFZ). Three 4-monthly treatments were administered to eligible pigs. A random selection of pigs were necropsied at baseline and at endline, 2–3.5 months after the final treatment. Additionally, untreated pigs from T1 and T2 areas were necropsied at endline to provide contemporaneous comparisons with T1 and T2 pigs. Baseline prevalence of viable T. solium cysticerci for T1 was 25.5% (Exact 95% CI: 13.9, 40.3; n = 12/47), and for T2 was 12.0% (CI: 6.4, 20.0; n = 12/100). At endline, prevalence was 2.8% for T1 (CI: 0.1, 14.5, n = 1/36) and 0% for T2 (CI: 0, 4.7, n = 0/77). Among untreated pigs, three had viable cysticerci, one from T1 area (12.5%, CI: 0.3, 52.7; n = 1/8) and two from T2 area (5.7%, CI: 0.7, 19.2, n = 2/35). Fisher’s exact test showed significant changes in prevalence from baseline to endline in both groups (T1: p = 0.005, T2: p = 0.001). Firth’s penalized Maximum Likelihood method suggested the changes were not significant relative to their controls (T1: p = 0.245, T2: p = 0.076). These findings showed a significant reduction in the prevalence of viable cysticerci from baseline to endline after both interventions. However, the changes could not be definitively attributed to the interventions due, in part, to small numbers of control pigs. Concurrent administration of the TSOL18 and OFZ cleared infection among assessed pigs whereas infection remained after treatment with OFZ only. Further studies including larger sample sizes would be required for more definitive conclusions. A One Health approach is recommended for rapid and sustainable impact.

The pork tapeworm T. solium affects the health and income of poor people in endemic areas. A pig vaccine—TSOL18, and a drug—oxfendazole (OFZ) present options for its control. In this study we assessed the effectiveness of the two tools against the parasite in pigs. We provided one group of pigs (T1) with a concurrent administration of TSOL18 and OFZ, and another group (T2) with OFZ only, in three rounds at 4 months intervals. We compared infection prevalence before and after the interventions by detection of cysticerci through carcase dissections. In addition, untreated pigs from the T1 and T2 areas were also sacrificed to serve as controls. We found a significant reduction in prevalence within the groups after the interventions. However, the reductions were not significant when compared with the reductions in the control groups, hence could not be definitively attributed to the interventions. Further, concurrent administration of TSOL18 and OFZ cleared infection among assessed pigs whereas OFZ alone did not clear the infection. Further studies would be required to make more definitive conclusions. We advocate for a One Health approach for a more rapid and sustainable impact.

Human Cysticercosis in Asia: A Systematic Review and Meta-Analysis

BACKGROUND

Cysticercosis in among the neglected tropical disease caused by eating the egg of parasite Taenia solium. In this review, we aimed to verify the prevalence of human cysticercosis in different countries of Asia using systematic review and meta-analysis approach.

METHODS

Based of the protocol, reliable databases including PubMed, SCOPUS, Science Direct, Embase, and Cochrane Library from 1990-2018 were searched using a panel of keywords. Overall, 48 countries of Asia were searched in turn and data were analyzed using a category of statistical tests.

RESULTS

Out of 28 included studies, 586175 samples were collected and included in the data analysis. Based on the meta-analysis results, the overall pooled percent of cysticercosis was estimated 3.8% (95% CI: [2.0, 7.0]). According to the result of heterogeneity statistics including I-squared, chi-square, and tau-squared, it was statistically significant (Tau2 = 2.94, chi2 = 12733.31, P<0.001, I2 = 100%) therefore a random effect model was used to handle the heterogeneity of studies. To evaluate the trend of cysticercosis over the time, Cumulative meta-analysis was performed and the result showed that there was a minor upward tendency in the prevalence of cysticercosis over the time.

CONCLUSION

Although, considering the religious culture and food habits in Asia, we might have expected to witness a low prevalence of human cysticercosis, but we noticed more or less significant infection in some countries of the region. Regarding the new feature of immigration and travel between countries, all authorities are advised to take measures on controlling and monitoring the disease.

Endemicity of Taenia solium cysticercosis in pigs from Mbeya Rural and Mbozi districts, Tanzania

BACKGROUND

Taenia solium taeniasis/cysticercosis is a disease of substantial economic and public health importance particularly in low-income countries. The disease was reported to be endemic in Mbeya Rural and Mbozi districts, in the southern highlands of Tanzania, the major pig production area in the country. In 2008, using B158/B60 antigen detection enzyme-linked immunosorbent assay (Ag-ELISA), porcine cysticercosis prevalence of up to 32% was reported in the districts. A number of interventions have been implemented in selected villages including an integrated approach consisting of improving pig confinement and selective treatment of pigs with oxfendazole. Mass drug administration with praziquantel targeting schistosomiasis, with an expected effect on T. solium, was also provided to school-age children in the area. This study aimed at providing an update on prevalence and intensities of porcine cysticercosis; and assessing farmers' knowledge, attitudes and practices which could be associated to disease transmission in the area. The study involved a questionnaire survey conducted using face-to-face household interviews with 890 consenting farmers; and carcass dissections performed on 282 pigs randomly selected from the surveyed households.

RESULTS

Twenty-six pigs (9.2%) were infected with T. solium; of which two-thirds (65.4%) had light to moderate infection intensities (1-1000 cysticerci), and one-third (34.6%) had heavy intensities (> 1000 cysticerci). Questionnaire results showed that only 5.7% of the respondents perceived T. solium cysticercosis to be an important disease in pigs. About 18.5% of the respondents were aware of T. solium taeniasis, but 32% of them were unaware of how the infection is acquired. Half of the respondents had seen cysticerci in pork, of whom 61% were not aware that consumption of infected pork could cause taeniasis. Latrines were observed to often (90%) lack doors with 45% considered accessible to pigs.

CONCLUSIONS

This study provided an evidence that the disease was still endemic in the area. Poor knowledge of farmers, attitudes, and risky practices responsible for disease perpetuation were also revealed. A One Health approach targeting the whole area incorporating improvement of farmer knowledge regarding disease transmission needs to be trialed as a feasible approach to control.

Understanding transmission and control of the pork tapeworm with CystiAgent: a spatially explicit agent-based model

BACKGROUND

The pork tapeworm, Taenia solium, is a serious public health problem in rural low-resource areas of Latin America, Africa and Asia, where the associated conditions of nuerocysticercosis (NCC) and porcine cysticercosis cause substantial health and economic harms. An accurate and validated transmission model for T. solium would serve as an important new tool for control and elimination, as it would allow for comparison of available intervention strategies, and prioritization of the most effective strategies for control and elimination efforts.

METHODS

We developed a spatially-explicit agent-based model (ABM) for T. solium ("CystiAgent") that differs from prior T. solium models by including a spatial framework and behavioral parameters such as pig roaming, open human defecation, and human travel. In this article, we introduce the structure and function of the model, describe the data sources used to parameterize the model, and apply sensitivity analyses (Latin hypercube sampling-partial rank correlation coefficient (LHS-PRCC)) to evaluate model parameters.

RESULTS

LHS-PRCC analysis of CystiAgent found that the parameters with the greatest impact on model uncertainty were the roaming range of pigs, the infectious duration of human taeniasis, use of latrines, and the set of "tuning" parameters defining the probabilities of infection in humans and pigs given exposure to T. solium.

CONCLUSIONS

CystiAgent is a novel ABM that has the ability to model spatial and behavioral features of T. solium transmission not available in other models. There is a small set of impactful model parameters that contribute uncertainty to the model and may impact the accuracy of model projections. Field and laboratory studies to better understand these key components of transmission may help reduce uncertainty, while current applications of CystiAgent may consider calibration of these parameters to improve model performance. These results will ultimately allow for improved interpretation of model validation results, and usage of the model to compare available control and elimination strategies for T. solium.

Neurocysticercosis-related seizures in the post-partum period: two cases and a review of the literature

Neurocysticercosis, the infection of the CNS with larval cysts of Taenia solium, is a leading cause of seizures in low-income countries. The clinical presentation of neurocysticercosis is variable and depends on the number, size, and location of cysticerci, and on the immune response of the host. In most patients, the affected site is the brain parenchyma, where cysts can precipitate seizures. Neurocysticercosis has seldom been described in pregnant women. In this Grand Round, we report two cases of pregnant women who immigrated to Italy from Bolivia and Ecuador, and who developed seizures in the early post-partum period, due to calcified parenchymal neurocysticercosis lesions. We discuss the complex interactions between neurocysticercosis and the immune system in pregnancy and the post-partum period. Building on this scenario, we propose practices for the management of neurocysticercosis in pregnancy and the post-partum period, highlighting important gaps in the literature that should be addressed.

Taenia solium Cysticercosis and Its Impact in Neurological Disease

Taenia solium neurocysticercosis (NCC) is endemic in most of the world and contributes significantly to the burden of epilepsy and other neurological morbidity. Also present in developed countries because of immigration and travel, NCC is one of few diseases targeted for eradication. This paper reviews all aspects of its life cycle (taeniasis, porcine cysticercosis, human cysticercosis), with a focus on recent advances in its diagnosis, management, and control. Diagnosis of taeniasis is limited by poor availability of immunological or molecular assays. Diagnosis of NCC rests on neuroimaging findings, supported by serological assays. The treatment of NCC should be approached in the context of the particular type of infection (intra- or extraparenchymal; number, location, and stage of lesions) and has evolved toward combined symptomatic and antiparasitic management, with particular attention to modulating inflammation. Research on NCC and particularly the use of recently available genome data and animal models of infection should help to elucidate mechanisms of brain inflammation, damage, and epileptogenesis.

Assessing the burden and spatial distribution of Taenia solium human neurocysticercosis in Ecuador (2013-2017)

Background

Estimating the burden of neglected tropical diseases is a valuable tool to support policymakers in the resource allocation for control and elimination of these diseases. Spatial analysis allows to identify the geographical distribution patterns of infectious and parasitic diseases within a country and allows to assess their possible correlation with other health disorders. Despite being neurocysticercosis (NCC) considered as the most important parasitic disease of the nervous system, few efforts have been addressed to assess the real burden of NCC in endemic countries, to date, there are no studies estimating the burden of NCC in South America. In this study we aimed to use the Disability Adjust Life Years (DALY) and spatial indicators as tools to measure the impact of human neurocysticercosis in Ecuador between 2013 and 2017.

Methods

Mortality, morbidity and spatial data from the national agency of statistics were used to estimate the burden of disease of NCC during a five-year period (2013–2017). NCC cases and its two main sequelae, epilepsy and migraine headache, were stratified by sex and age group to calculate the DALY associated to NCC using the DALY package in R. SATSCAN software was used to assess spatial clusters of NCC and its possible neurological sequelae as epilepsy, status epilepticus, migraine and hydrocephalus.

Principal findings

The burden of human neurocysticercosis ranged from 56201 [95% CI 29961–89333] to 59612 [95% CI 31854–94689] DALY per year, corresponding to 3.54 to 3.56 DALY per 1000 population. Average yearly incidence rates per 10 000 person-years were 0.23 [95% CI 0.21–0.26] for NCC, 4.89 [95% CI 4.78–5.00] for epilepsy, 0.130 [95% CI 0.11–0.15] for status epilepticus, 0.62 [95% CI 0.58–0.66] for migraine headache, and 1.02 [95% CI 0.98–1.07] for hydrocephalus. Most important significant spatial clusters (p<0.0001) were located in the southern region of the highlands of the country.

Conclusion/Significance

This is the first study in South America to calculate estimates for burden of NCC and one of the few using spatial analysis to show the importance of sequelae other than epilepsy that play an important role in the impact of human neurocysticercosis.

Taenia solium-neurocysticercosis (NCC) is a neglected parasite infection in humans causing a variety of neurological sequelae like epilepsy, and chronic headache. The purpose of this study was to estimate the burden of NCC in Ecuador using official nation-wide databases from the National Institute of Statistics and Census (INEC) for the period of 2013–2017, and to assess for spatial clusters of four neurological disorders associated with NCC. The burden of NCC measured in Disability Adjusted Life Years (DALY) was estimated in 3.54 to 3.56 DALY per 1000 population. Several significant spatial clusters for augmented risk of disease were identified along the country for NCC and its sequelae, most of which converged in the southern Sierra provinces. Our study suggests a possible spatial correlation between the presence of NCC cases and a higher prevalence of neurological conditions like epilepsy, status epilepticus, migraine, and hydrocephalus in several ‘hot spots’ of the southern provinces of Ecuador, indicating possible areas where the application of preventive measures is necessary to reduce cysticercosis transmission rates.

Host immune responses during Taenia solium Neurocysticercosis infection and treatment

Taenia solium cysticercosis and taeniasis (TSCT), caused by the tapeworm T. solium, is a foodborne and zoonotic disease classified since 2010 by WHO as a neglected tropical isease. It causes considerable impact on health and economy and is one of the leading causes of acquired epilepsy in most endemic countries of Latin America, Sub-Saharan Africa, and Asia. There is some evidence that the prevalence of TSCT in high-income countries has recently increased, mainly due to immigration from endemic areas. In regions endemic for TSCT, human cysticercosis can manifest clinically as neurocysticercosis (NCC), resulting in epileptic seizures and severe progressive headaches, amongst other neurological signs and/or symptoms. The development of these symptoms results from a complex interplay between anatomical cyst localization, environmental factors, parasite's infective potential, host genetics, and, especially, host immune responses. Treatment of individuals with active NCC (presence of viable cerebral cysts) with anthelmintic drugs together with steroids is usually effective and, in the majority, reduces the number and/or size of cerebral lesions as well as the neurological symptoms. However, in some cases, treatment may profoundly enhance anthelmintic inflammatory responses with ensuing symptoms, which, otherwise, would have remained silent as long as the cysts are viable. This intriguing silencing process is not yet fully understood but may involve active modulation of host responses by cyst-derived immunomodulatory components released directly into the surrounding brain tissue or by the induction of regulatory networks including regulatory T cells (Treg) or regulatory B cells (Breg). These processes might be disturbed once the cysts undergo treatment-induced apoptosis and necrosis or in a coinfection setting such as HIV. Herein, we review the current literature regarding the immunology and pathogenesis of NCC with a highlight on the mobilization of immune cells during human NCC and their interaction with viable and degenerating cysticerci. Moreover, the immunological parameters associated with NCC in people living with HIV/AIDS and treatments are discussed. Eventually, we propose open questions to understand the role of the immune system and its impact in this intriguing host-parasite crosstalk.

The Gut-Brain-Axis on the Manifestation of Depressive Symptoms in Epilepsy: An Evidence-Driven Hypothesis

Epilepsy is a severe neurological disorder involving 70 million people around the globe. Epilepsy-related neuropsychiatric comorbidities such as depression, which is the most common, is an additional factor that negatively impacts the living quality of epilepsy patients. There are many theories and complexities associated with both epilepsy and associated comorbidities, one of which is the gut-brain-axis influence. The gut microbiome is hypothesized to be linked with many neurological disorders; however, little conclusive evidence is available in this area. Thus, highlighting the role will create interest in researchers to conduct detailed research in comprehending the influence of gut-brain-axis in the manifestation of depressive symptoms in epilepsy. The hypothesis which is explored in this review is that the gut-brain-axis do play an important role in the genesis of epilepsy and associated depression. The correction of this dysbiosis might be beneficial in treating both epilepsy and related depression. This hypothesis is illustrated through extensive literature discussion, proposed experimental models, and its applicability in the field. There is indirect evidence which revealed some specific bacterial strains that might cause depression in epilepsy.

Epidemiology and surveillance of human (neuro)cysticercosis in Europe: is enhanced surveillance required?

OBJECTIVES

To report on relevant national surveillance systems of (N)CC and taeniasis (the infection with the adult tapeworm) in the European Union/European Economic Area and to assess the magnitude of (N)CC occurrence by retrieving information on cases for the period 2000-2016.

METHODS

(N)CC cases were retrieved via national reporting systems, a systematic literature search, contact with clinicians and a search for relevant 'International Statistical Classification of Diseases and Related Health Problems' (ICD)-based data.

RESULTS

Mandatory notification systems for (N)CC were found in Hungary, Iceland and Poland. Ten cases were reported in Poland and none in Hungary and Iceland. Through the systematic literature review and information given by clinicians, 263 individual and 721 aggregated (N)CC cases from 19 European countries were identified. ICD-based data were obtained from five countries. From 2000 to 2016, a total of 3489 cases (N)CC cases were coded: 832 in Italy, eight in Latvia, 357 in Portugal, 2116 in Spain and 176 in Sweden.

CONCLUSION

Despite being classified as a possible eradicable disease, (N)CC is still diagnosed across Europe, yet its true extent and impact remain unclear.

Neurocysticercosis in people with epilepsy in Sub-Saharan Africa: A systematic review and meta-analysis of the prevalence and strength of association

PURPOSE

We analyzed studies on neurocysticercosis (NCC) and epilepsy across Sub-Saharan Africa (SSA) to determine the prevalence of NCC in people with epilepsy (PWE) and the strength of association of NCC with epilepsy in the region.

METHODS

We conducted a systematic review of the existing literature on NCC and epilepsy in SSA. Diagnostic methods for NCC in the studies selected for our analysis included one or more of the following: positive brain CT, serum ELISA and serum EITB. A common prevalence and overall odds-ratio were then estimated using meta-analysis.

RESULTS

A total of 25 (overall) and 20 (case-control) studies met the inclusion criteria for the prevalence and strength of association estimation, respectively. The overall prevalence estimate of NCC in PWE was 22 % [95 % confidence interval [CI]: 17-27.0 %). The figures were higher in the Southern and Eastern Africa sub-region (45 % and 25 % respectively) but lower in the Central and Western Africa sub-region (6 % and 15 % respectively). The prevalence of NCC estimate in PWE varied with method of diagnosis; with 29 % 18 % and 15 % in studies that used a minimum of Brain CT, ELISA and EITB respectively. The overall odds ratio was 2.4 (95 % CI 2.1-2.8), p < 0.0001.

CONCLUSION

The overall prevalence of NCC in PWE in SSA was 22 %. The prevalence figure varied with the sub-region of SSA. The odd of NCC in PWE in SSA was 2.4. In spite of the sub-regional variation in NCC prevalence, this meta-analysis suggests that neurocysticercosis contributes significantly to epilepsy in SSA.

Performance of a Sandwich Antigen-Detection ELISA for the Diagnosis of Porcine Taenia solium Cysticercosis

The pig is the natural intermediate host of Taenia solium, a parasite causing significant burden of disease in both humans and pigs. Porcine cysticercosis is traditionally detected via tongue palpation and slaughterhouse meat inspection, both with limited sensitivity. Serum antibody detection has a better performance; however, it does not discriminate past from present infection. Serum antigen detection can demonstrate viable infection and gives a good estimate of parasitic load. This study evaluated a sandwich antigen-detection ELISA using monoclonal antibodies (MoAbs) 158C11 and 60H8 for the diagnosis of viable cysticercosis in pigs. Serum samples were used from 35 naturally T. solium cysticerci-infected pigs, 31 cysticercosis-negative pigs, and 22 pigs with Taenia hydatigena infection (to assess cross-reactions). Positive cysticercosis samples were subcategorized at necropsy according to parasitic burden as mild (1-10 viable cysts, n = 10), moderate (11-100 cysts, n = 5), or severe infection (more than 100 cysts, n = 20). This Ag-ELISA showed a sensitivity of 82.9% and a specificity of 96.8% when not considering cross-reactions with T. hydatigena. Hundred percentage of severely infected, 80% of moderately infected, and 50% of mildly T. solium-infected pigs tested positive. Twenty of 22 pigs with only T. hydatigena infections were positive, with 13 reaching saturating levels in the ELISA. The Ag-ELISA revealed the presence of live cysts and is, thus, a fairly reliable test to monitor experimental infection, response to treatment, and follow-up in animal models of cysticercosis. It should, however, be carefully interpreted when used in regions where T. hydatigena is endemic in pigs.

Use of magnetic particles in the purification of IgM antibodies against Taenia solium

The use of L protein coupled magnetic particles for the concentration and purification of immunoglobulin M (mIgM) monoclonal antibodies against Taenia solium was evaluated. Three concentration methods and different elution times were evaluated and the ratio of particles to the ratio of mIgM was optimized. It is demonstrated that: 1) with the use of magnetic particles, a previous concentration of mIgM is not required, which reduces the manipulation of the antibodies and improves the recovery, 2) the use of a binding buffer can be omitted, since the pH of most cell culture supernatants are neutral, and 3) longer elution times (~ 45 minutes) are needed to increase recovery to a level greater than 80%. The study demonstrates that the use of L protein-coupled magnetic particles is a simple and efficient tool for mIgM concentration and purification.

Public policy for controlling the taeniasis/cysticercosis complex in Colombia

The teniosis/cysticercosis (T/C) complex is a parasitic disease caused by the cestodes Taenia solium and Taenia saginata, and is considered as a neglected zoonosis by the World Health Organization (WHO) and the Colombian Ministry of Health and Social Protection. (1-3) This parasitic infection is a public health and environmental problem in Latin-American, African and Asian countries, and is currently being introduced to developed countries through immigrant communities. Estimates are that 2 500 000 people are infected with this complex and that twice as many individuals develop the parasite at the tissue level. This disease is associated to 50 000 deaths every year, but these figures need to be updated. (4-8)

Microsurgical Treatment of Epilepsy with Parenchymal Neurocysticercosis

Parenchymal neurocysticercosis is the most common form of neurocysticercosis in the central nervous system (CNS), which mainly causes epilepsy and usually responses well to routine medications. However, there are appreciable cases of relapses refractory to medical treatment. We investigated microsurgical treatment of epilepsy with parenchymal neurocysticercosis. Nine cases of epilepsy caused by parenchymal neurocysticercosis from 2002 to 2018 were analyzed retrospectively. Cysts in 7 cases were completely removed. No case died of operation and no new dysfunction of the nervous system was observed after surgery. Among the other 9 cases, 8 cases became seizure-free or controlled by medicine according to the postoperative follow-up for 6 months to 9 years. One case was lost for follow-up. It was suggested that epilepsy with parenchymal neurocysticercosis can usually be controlled after routine medications. However, surgery is still indicated in some cases and careful microsurgery is associated with satisfactory clinical outcomes in appropriately selected cases.

Taenia solium cysticercosis and taeniasis in urban settings: Epidemiological evidence from a health-center based study among people with epilepsy in Dar es Salaam, Tanzania

In Africa, urbanization is happening faster than ever before which results in new implications for transmission of infectious diseases. For the zoonotic parasite Taenia solium, a major cause of acquired epilepsy in endemic countries, the prevalence in urban settings is unknown. The present study investigated epidemiological, neurological, and radiological characteristics of T. solium cysticercosis and taeniasis (TSCT) in people with epilepsy (PWE) living in Dar es Salaam, Tanzania, one of the fastest growing cities worldwide. A total of 302 PWE were recruited from six health centers in the Kinondoni district of Dar es Salaam. Serological testing for T. solium cysticercosis-antigen (Ag) and -antibodies (Abs) and for T. solium taeniasis-Abs was performed in all PWE. In addition, clinical and radiological examinations that included cranial computed tomography (CT) were performed. With questionnaires, demographic data from study populations were collected, and factors associated with TSCT were assessed. Follow-up examinations were conducted in PWE with TSCT. T. solium cysticercosis-Ag was detected in three (0.99%; 95% CI: 0–2.11%), -Abs in eight (2.65%; 95% CI: 0.84–4.46%), and taeniasis-Abs in five (1.66%; 95% CI: 0.22–3.09%) of 302 PWE. Six PWE (1.99%; 95% CI: 0.41–3.56%) were diagnosed with neurocysticercosis (NCC). This study demonstrates the presence of TSCT in Dar es Salaam, however, NCC was only associated with a few cases of epilepsy. The small fraction of PWE with cysticercosis- and taeniasis-Abs may suggest that active transmission of T. solium plays only a minor role in Dar es Salaam. A sufficiently powered risk analysis was hampered by the small number of PWE with TSCT; therefore, further studies are required to determine the exact routes of infection and risk behavior of affected individuals.

Taenia solium cysticercosis and taeniasis is a zoonotic disease complex which affects thousands of people in sub-Saharan Africa. This parasite has a human-pig life cycle and has been considered a public health problem mainly in rural areas. As African towns and suburbs grow rapidly and disproportionally, adequate infrastructure such as sewage systems and clean water often lack while population density, trade, and travel increase. This may lead to the appearance of parasitic diseases formerly considered `rural´ in urban settings. In this study, we searched for evidence of T. solium infections in the Kinondoni district of Dar es Salaam, Tanzania. We focused on people with epilepsy (PWE) since epilepsy is one of the most common and severe disorders associated with T. solium neurocysticercosis and tested all of them serologically for T. solium cysticercosis and taeniasis. We further investigated neurological and radiological characteristics. Our findings show that in our study area in Dar es Salaam 2.65% of PWE had contracted T. solium infection at some stage. Neurocysticercosis, as confirmed by neuroimaging, was found only in 1.99% of PWE. This, in combination with the relatively small number of PWE detected with taeniasis antibodies (1.66%), points towards the fact that active transmission of T. solium seems to play only a minor role in this urban setting, suggesting that infections may mainly be contracted in rural areas. Further large-scale studies are required to investigate the infection pathways and risk behavior related to T. solium infections within urban areas of sub-Saharan Africa.