Epidemiological, clinical and radiological characteristics of people with neurocysticercosis in Tanzania-A cross-sectional study

Evaluation of a rapid lateral flow assay for the detection of taeniosis and cysticercosis at district hospital level in Tanzania: A prospective multicentre diagnostic accuracy study

The TS POC test, Taenia solium point-of-care test, is a two-strip lateral flow assay using the recombinant antigen rES33 on the TS POC T test strip, and rT24H on the TS POC CC test strip, to detect antibodies against T. solium taeniosis and cysticercosis, respectively. The objective of this study was to assess the diagnostic performance of the TS POC test for the detection of T. solium taeniosis and cysticercosis in individuals attending district hospitals in Tanzania. In this prospective two-phase diagnostic accuracy study, we recruited participants aged 10 and above, excluding pregnant women and those with acute severe illness. Participants were consecutively recruited in three cohorts according to their signs/symptoms: compatible with neurocysticercosis (cohort 1), intestinal worm infections (cohort 2), and other signs/symptoms (cohort 3). Lacking a gold standard test for both infections, diagnostic accuracy was evaluated using results of two coprological and two serological tests for taeniosis, and three serological tests for cysticercosis, in a Bayesian Latent Class Model approach. The TS POC test was conducted on 601 participants in cohort 1, 1661 participants in cohort 2, and 662 participants in cohort 3. Most individuals tested negative on both TS POC test strips, with proportions of 83% (n = 496), 97% (n = 1613) and 97% (n = 641) in cohorts 1, 2 and 3, respectively. Complete case data were available for 120, 114, and 53 participants for taeniosis, and 126, 122, and 55 participants for cysticercosis. Sensitivity values for the TS POC T test strip were 50.2% [95% credible interval 4.9 - 96.4], 40.8% [2.2 - 95.2], and 40.4% [2.3 - 95.0], while specificity values were 98.6% [97.1 - 99.6], 99.3% [98.7 - 99.7] and 99.4% [98.5 - 99.9], respectively. For the TS POC CC test strip, the sensitivity was 77.5% [37.8 - 99.2], 24.9% [95% CI 6.4 - 52.7] and 44.2% [6.6 - 91.5], and the specificity 92.3% [86.5 - 98.8], 99.1% [97.8 - 100], and 98.1% [96.1 - 99.7] across the respective cohorts. Although the TS POC test has a low sensitivity, it demonstrates a high specificity, which may have clinical utility to guide treatment and diagnostic decisions, or in epidemiological studies. An important strength of this study lies in its assessment of the TS POC test under real-world conditions, revealing divergent estimates across distinct cohorts. The study underscores the suboptimal performance of existing tests under field conditions, emphasizing the need to enhance and validate these tests for better performance in practical real-world settings. Registration number: PACTR201712002788898.

Neurocysticercosis and cognitive impairment among people with epilepsy in Taenia solium endemic regions of rural southern Tanzania: A hospital-based cross-sectional study in mental health clinics of selected sites in Tanzania

BACKGROUND

Epilepsy poses a significant public health problem in many parts of the world. The majority of people with epilepsy (PWE) are from low-income and middle-income countries (LMICs). Taenia solium neurocysticercosis (NCC) is estimated to cause 30% of preventable epilepsy in PWE in areas of T. solium endemicity. This study was conducted to assess the prevalence of NCC in PWE, evaluate the presence of cognitive impairment in PWE and assess potentially contributing factors.

METHODS

PWE were recruited within a mental health clinic-based cross-sectional study in rural Southern Tanzania. PWE underwent a detailed neurological examination, including mental state, and a blood sample was collected for T. solium cysticercosis (CC) serology testing. Patients who were serologically positive for CC and those detected to have prominent neurological deficits apart from epilepsy were invited to receive a cerebral computed tomography (CT) examination.

RESULTS

Out of the 223 people with epilepsy (PWE) recruited, 221 underwent clinical examination. Among these, 26 (11.8 %) had cognitive impairment, and 2 had neurological signs or symptoms without cognitive impairment. Twenty-five of the 223 PWE (11.2 %) tested positive for CC, of which 4 had cognitive impairment. One hundred and ninety-eight (88.8 %) tested negative for CC, of which 22 had cognitive impairment. A total of 36 participants underwent CT scans, with 18 testing positive and 18 testing negative for CC. Of the 36 who had CT scans, 8 (22.2 %) were diagnosed with NCC; 7 were CC positive, and 1 was CC negative; only the latter had cognitive impairment. Multivariate logistic regression confirmed that cognitive impairment in PWE was 8.62 times higher for Kongwa participants than Chunya, with a statistically significant association (95 % CI: 1.75, 156; p = 0.037). Additionally, having and education was associated with a 91 % reduction in the odds of cognitive impairment (OR = 0.09) compared to no education, which was also statistically significant (95 % CI: 0.01, 0.33; p = 0.002). There was no association between cognitive impairment and NCC.

CONCLUSION

Our study found a 22.2 % prevalence of NCC among PWE. Cognitive impairment was present in 11.8 % of PWE but was not significantly associated with NCC. Socioeconomic and educational factors may play a larger role in cognitive impairment among PWE.

Neurocysticercosis Prevalence and Characteristics in Communities of Sinda District in Zambia: A Cross-Sectional Study

BACKGROUND

This study aimed at describing the epidemiology of (neuro)cysticercosis as well as its clinical and radiological characteristics in a Taenia solium endemic district of Zambia.

METHODS

This was part of a cross-sectional community-based study conducted in Sinda district to evaluate an antibody-detecting T. solium point-of-care (TS POC) test for taeniosis and (neuro)cysticercosis. All TS POC cysticercosis positive (CC+) participants and a subset of the TS POC cysticercosis negative (CC-) received a clinical evaluation and cerebral computed tomography (CT) examination for neurocysticercosis (NCC) diagnosis and staging.

RESULTS

Of the 1249 participants with a valid TS POC test result, 177 (14%) were TS POC CC+ . Cysticercosis sero-prevalence was estimated to be 20.1% (95% confidence intervals [CI] 14.6-27.0%). In total, 233 participants received a CT examination (151 TS POC CC+ , 82 TS POC CC-). Typical NCC lesions were present in 35/151 (23%) TS POC CC+ , and in 10/82 (12%) TS POC CC- participants. NCC prevalence was 13.5% (95% CI 8.4-21.1%) in the study population and 38.0% (95% CI 5.2-87.4%) among people reporting epileptic seizures. Participants with NCC were more likely to experience epileptic seizures (OR = 3.98, 95% CI 1.34-11.78, p = 0.01) than those without NCC, although only 7/45 (16%) people with NCC ever experienced epileptic seizures. The number of lesions did not differ by TS POC CC status (median: 3 [IQR 1-6] versus 2.5 [IQR 1-5.3], p = 0.64). Eight (23%) of the 35 TS POC CC+ participants with NCC had active stage lesions; in contrast none of the TS POC CC- participants was diagnosed with active NCC.

CONCLUSION

NCC is common in communities in the Eastern province of Zambia, but a large proportion of people remain asymptomatic.

Evaluating the modulation of peripheral immune profile in people living with HIV and (Neuro)cysticercosis

BACKGROUND

The parasitic infection caused by Taenia solium represents a significant public health concern in developing countries. Larval invasion of body tissues leads to cysticercosis (CC), while central nervous system (CNS) involvement results in neurocysticercosis (NCC). Both conditions exhibit diverse clinical manifestations, and the potential impact of concomitant HIV infection especially prevalent in sub-Saharan Africa on peripheral and CNS immune responses remains poorly understood. This study aimed to identify the potential impact of HIV coinfection in CC and NCC patients.

METHODOLOGY

A nested study within a cross-sectional analysis in two Tanzanian regions was performed and 234 participants (110 HIV+ and 124 HIV-) were tested for cysticercosis antibodies, antigens, CD4 counts and serum Th1 and Th2 cytokines via multiplex bead-based immunoassay. 127 cysticercosis seropositive individuals underwent cranial computed tomography (CCT) and clinical symptoms were assessed. Multiple regression analyses were performed to identify factors associated with cytokine modulation due to HIV in CC and NCC patients.

RESULTS

Serologically, 18.8% tested positive for cysticercosis antibodies, with no significant difference HIV+ and HIV+. A significantly higher rate of cysticercosis antigen positivity was found in HIV+ individuals (43.6%) compared to HIV- (28.2%) (p = 0.016). CCT scans revealed that overall 10.3% had active brain cysts (NCC+). Our study found no significant changes in the overall cytokine profiles between HIV+ and HIV- participants coinfected CC and NCC, except for IL-5 which was elevated in HIV+ individuals with cysticercosis. Furthermore, HIV infection in general was associated with increased levels of pro-and some anti-inflammatory cytokines e.g. TNF-α, IL-8, and IFN-γ. However, based on the interaction analyses, no cytokine changes were observed due to HIV in CC or NCC patients.

CONCLUSIONS

In conclusion, while HIV infection itself significantly modulates levels of key cytokines such as TNF-α, IL-8, and IFN-γ, it does not modulate any cytokine changes due to CC or NCC. This underscores the dominant influence of HIV on the immune system and highlights the importance of effective antiretroviral therapy in managing immune responses in individuals coinfected with HIV and CC/NCC.

Circulating cell-free DNA as a biomarker for molecular diagnosis of Neurocysticercosis

Taenia solium is a widespread zoonotic tapeworm that predominantly affects regions of Latin America, South and South-East Asia, and Sub-Saharan Africa. Neurocysticercosis (NCC), the presence of T. solium cysts in the brain is associated with diverse clinical manifestations, such as epilepsy, seizures, and neurological deficits. It is a significant cause of preventable epilepsy globally, accounting for approximately 30% of cases in endemic regions. The diagnosis of neurocysticercosis relies on neuroimaging techniques, but these resources are often limited in low-income countries, resulting in an underestimation of the disease burden. The present study enrolled 141 patients who were clinically suspected and radiologically confirmed for NCC at the Neurology OPD of PGIMER, Chandigarh. Additionally, 98 control subjects attending the PGIMER OPD for investigation were also included. Plasma and urine samples were collected from all participants for further analysis. Cell-free DNA extraction was performed using specific kits, and the quality of the extracted DNA was assessed. The RT-LAMP assay targeted the cox1 gene. Real-time RT-LAMP results were evaluated using a fluorescence graph obtained with the Genei III fluorimeter. Among a group of patients diagnosed with NCC, the gene was identified in 74.4% of plasma samples and 67.3% of urine samples. In comparison, the T. solium cox1 gene was found in 6.1% of control subjects in plasma and urine samples using the LAMP assay. In conclusion, the study emphasises the need for improved diagnostic methods for NCC and presents promising alternatives, such as RT-LAMP and urine-based cell-free DNA analysis. These approaches offer advantages in terms of cost-effectiveness, simplicity, and diagnostic accuracy.

Treatment Outcome in Patients with Disseminated Cysticercosis: A Systematic Review of Case Reports and Case Series

Disseminated cysticercosis is defined by multiple brain lesions and involvement of other body sites. Cysticidal treatment in disseminated cysticercosis is considered life-threatening. We conducted a systematic review of all published cases and case series to assess the safety and efficacy of cysticidal treatment. We conducted a systematic review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (PROSPERO CRD42022331895) to assess the safety and efficacy of cysticidal treatment. Using the search term "disseminated neurocysticercosis OR disseminated cysticercosis," databases like PubMed, Scopus, Embase, and Google Scholar were searched. Outcomes included death and secondary measures like clinical improvement and lesion reduction. We calculated the predictors of primary outcome (death) using the binary logistic regression analysis. We reviewed 222 published cases from 101 publications. Approximately 87% cases were reported from India. Of 222 cases, 134 (60%) received cysticidal treatment. Follow-up information was available from 180 patients, 11 of them died, and 169 showed clinical improvement. The death rate was 4% (5 out of 114) in patients treated with cysticidal drugs plus corticosteroids, in comparison with 13% (5 out of 38) in patients who were treated with corticosteroids alone. All patients using only praziquantel faced fatality. Death predictors identified were altered sensorium and lack of treatment with albendazole. We noted that the risk of death after cysticidal treatment is not as we expected, and a multicentric randomized controlled trial is needed to resolve this issue.

Integration of onchocerciasis morbidity management and disability prevention services in the healthcare system in Tanzania: a call for action and recommendations

Onchocerciasis is among the Neglected Tropical Diseases (NTDs) responsible for dermatological, ophthalmological, and neurological manifestations. With the ongoing burden of onchocerciasis clinical manifestations, morbidity management, and disability prevention services are required to alleviate the suffering of the affected populations. Unfortunately, despite the ongoing transmission of onchocerciasis, morbidity management, and disability prevention services are limited in Tanzania. Therefore, this article highlights the concept of onchocerciasis morbidity management and disability prevention, along with the significance of its adoption in the healthcare system in Tanzania. We further provide recommendations on where and how to start.

Evaluation of a point-of-care test for the diagnosis of Taenia solium neurocysticercosis in rural southern Tanzania: a diagnostic accuracy study

BACKGROUND

Neurocysticercosis is a common cause of epilepsy in Taenia solium-endemic areas in sub-Saharan Africa but is often undiagnosed because of an absence of affordable diagnostic tools. This study evaluated the diagnostic accuracy of a T solium cysticercosis antibody-detecting lateral-flow point-of-care assay (TS POC test) for the neuroimaging-based diagnosis of neurocysticercosis.

METHODS

Patients with epileptic seizures or severe progressive headache were recruited consecutively from three hospitals in southern Tanzania. All patients were tested with the TS POC test. All patients positive for cysticercosis on the TS POC test and every tenth patient who was negative for cysticercosis received a brain CT examination and underwent reference testing for T solium cysticercosis (ie, rT24H-EITB, LLGP-EITB, and antigen ELISA). The primary outcome of the study was the sensitivity of the TS POC test for the diagnosis of neurocysticercosis.

FINDINGS

Of the 601 recruited participants, 102 (17%) tested positive for cysticercosis with the TS POC test. Overall, 48 (62%) of the 77 patients positive for cysticercosis and five (17%) of the 29 patients negative for cysticercosis on the TS POC test had CT-confirmed neurocysticercosis. The TS POC test yielded a sensitivity of 49% (uncertainty interval [UI] 41-58) for neurocysticercosis. Sensitivity was similar to that of the rT24H-EITB (44%, UI 37-51) and the antigen ELISA (50%, 43-56). For the subset of neurocysticercosis cases with at least one active (ie, vesicular) lesion, sensitivity was above 98% for the TS POC test, the rT24H-ETIB, and the antigen ELISA.

INTERPRETATION

The TS POC test showed promising results for the diagnosis of neurocysticercosis in patients with vesicular lesions, which need to be confirmed in a larger study. This test could be considered to support policies on screening patients with suspected neurocysticercosis in clinical settings, which would allow appropriate referral for neuroimaging and early treatment.

FUNDING

German Federal Ministry of Education and Research and the European & Developing Countries Clinical Trials Partnership.

TRANSLATION

For the Swahili translation of the abstract see Supplementary Materials section.

Severe neurocysticercosis in a quaternary hospital from Mozambique: Case series analysis

BACKGROUND

Neurocysticercosis (NCC) is severe and leading global cause of morbidity and mortality. The disease presents with a variety of clinical presentations from focal to diffuse neurological symptoms. Despite being an endemic country, there are no studies describing the clinico-epidemiological characteristics of NCC in Mozambique. Herein, we describe a consecutive cases series of NCC from the national reference Hospital in Maputo, capital of Mozambique.

METHODS

Consecutive cases of NCC diagnosed during a 3-year period (January/2020-December/2022) were retrieved from the institutional clinical files and imaging database.

RESULTS

Six cases of NCC were identified, with mean age of 43.1 years (range 26-66). Four were males (66.6 %). The median time from the beginning of clinical manifestations to the diagnosis was 6 months (range 3-18 months). All patients presented with severe parenchymal NCC, with seizures (n = 5, 83 %) being the most common manifestation. Other clinical manifestations were dementia (n = 1) and hydrocephalus (n = 1). The imaging showed multiple lesions at different stages, with half (n = 3) of them showing the coexistence of nodular calcified lesions at earlier stages (vesicular, colloidal and granular stages). Patients were treated with anthelminthic drugs, corticosteroids and anticonvulsants and no deaths to report. The 3rd month modified Rankin scale was ≤ 2 in 83 % of patients.

CONCLUSION

In our case series, patients with NCC presented very late, with severe advanced stage disease, with multiple coexistent short and long-term brain lesions. These findings can be explained eventually because of the Maputo Central Hospital being national referral center receiving commonly more severe cases. Studies aiming to clarify the diagnosis pathways/barriers and NCC awareness among medical doctors working at primary and secondary health care level is mandatory to assess the real burden of NCC and implement timely diagnosis and care of patients affected by this neglected disease.

Report of three patients with extensive neurocysticercosis in rural southern Tanzania: neurological, serological and neuroradiological findings

BACKGROUND

Neurocysticercosis (NCC) is common in eastern Africa, but disease presentation varies considerably. Most patients have single or few NCC-typical lesions in their brain but some present with a large number of lesions. We present three patients with positive antibody-based serology for Taenia solium cysticercosis screened at the Vwawa district hospital, Mbozi district, southern Tanzania, in whom extensive NCC was confirmed by neuroimaging.

CASE PRESENTATIONS

Patient 1 was a 55-year-old female from the tribe Malila smallholder farmer who has had four generalized tonic-clonic epileptic seizures over a period of 11 years and one episode of transient left hemiparesis one year before seizure onset. The patient also reported monthly to weekly episodes of severe, progressive, unilateral headache. The computed tomography (CT) scan of the brain showed 25 NCC lesions of which 15 were in the vesicular stage. Patient 2 was a 30-year-old male from tribe Nyha mechanic who reported monthly episodes of moderate to severe, progressive, bilateral headache, but no epileptic seizures. The CT scan showed 63 NCC lesions of which 50 were in the vesicular stage. Patient 3 was a 54-year-old female from the tribe Malila smallholder farmer who suffered from frequent generalized tonic-clonic epileptic seizures with potential signs of focal seizure onset. She also reported weekly to daily episodes of severe, progressive, unilateral headache. The CT scan showed 29 NCC lesions of which 28 were in the vesicular stage.

CONCLUSIONS

Clinical presentation of NCC with multiple brain lesions varies considerably ranging from few epileptic seizures and severe headache to severe epilepsy with frequent epileptic seizures. Individuals with neurological signs/symptoms that may be due to NCC, based for example on epidemiological criteria or serological evidence of cysticercosis, are recommended to undergo neuroimaging before anthelminthic treatment is considered.

Efficacy and safety of antiparasitic therapy for neurocysticercosis in rural Tanzania: a prospective cohort study

PURPOSE

Neurocysticercosis is common in regions endemic for Taenia solium. Active-stage neurocysticercosis can be treated with antiparasitic medication, but so far no study on efficacy and safety has been conducted in Africa.

METHODS

We conducted a prospective cohort study on treatment of neurocysticercosis in Tanzania between August 2018 and January 2022. Patients were initially treated with albendazole (15 mg/kg/d) for 10 days and followed up for 6 months. Additionally in July 2021, all participants who then still had cysts were offered a combination therapy consisting of albendazole (15 mg/kg/d) and praziquantel (50 mg/kg/d). Antiparasitic treatment was accompanied by corticosteroid medication and anti-seizure medication if the patient had experienced epileptic seizures before treatment.

RESULTS

Sixty-three patients were recruited for this study, of whom 17 had a complete follow-up after albendazole monotherapy. These patients had a total of 138 cysts at baseline, of which 58 (42%) had disappeared or calcified by the end of follow-up. The median cyst reduction was 40% (interquartile range 11-63%). Frequency of epileptic seizures reduced considerably (p < 0.001). Three patients had all active cysts resolved or calcified and of the remaining 14, eight received the combination therapy which resolved 63 of 66 cysts (95%). Adverse events were infrequent and mild to moderate during both treatment cycles.

CONCLUSION

Cyst resolution was unsatisfactory with albendazole monotherapy but was very high when it was followed by a combination of albendazole and praziquantel.

Knowledge and misconceptions about epilepsy among people with epilepsy and their caregivers attending mental health clinics: A qualitative study in Taenia solium endemic pig-keeping communities in Tanzania

OBJECTIVE

Taenia solium (T. solium) neurocysticercosis (NCC) affects the central nervous system and is associated with 30% of acquired epilepsy in some endemic areas. Epilepsy is a stigmatizing disease in many societies and people with epilepsy (PWE) and their families experience discrimination. This study aimed to explore the knowledge, perceptions, and experiences of epilepsy among PWE and their caregivers attending mental health clinics.

METHODS

In T. solium endemic areas of Tanzania, PWE and their caregivers attending mental health clinics were identified and their informed consent was sought prior to study participation. In-depth interviews were conducted in Swahili language and analyzed thematically. The coding was undertaken by two independent researchers using NVivo (Version 12, QSR International).

RESULTS

Thirty-eight participants were interviewed. Three themes were identified during the analysis, namely, knowledge about epilepsy; perception of epilepsy; and experience with epilepsy among PWE and their caregivers. Participants commonly defined epilepsy as a "falling disease," perceived to be caused by witchcraft, and were unaware of the association between T. solium and epilepsy. Stigmatization of epilepsy was reported as a problem. Reported treatment patterns after the initial onset of epilepsy varied widely; however, patients usually began treatment with traditional healing methods, and only later opted for biomedical treatment. Patients had generally poor adherence to antiseizure medication, which could be caused by inadequate knowledge or irregular supply.

SIGNIFICANCE

Level of knowledge about epilepsy was low, and NCC was not mentioned as a cause of epilepsy among participants. Epilepsy was generally perceived to be the result of witchcraft, evil spirits, or curses. Health education is needed, including an explanation of the model of T. solium transmission and the insistence on hygiene measures. This could reduce the number of new infections with T. solium, improve access to prompt biomedical treatment, and improve the lives of PWE.

Neurocysticercosis: A Review into Treatment Options, Indications, and Their Efficacy

Neurocysticercosis, due to the localization of Taenia solium larvae in the Central Nervous System, is a neglected tropical disease still endemic in much of Latin America, Asia and sub-Saharan Africa. The therapeutic management of NC has gradually improved with the establishment of neuroimaging studies (CT and MRI) in endemic countries and with the demonstration of the efficacy of albendazole and praziquantel in the 1980s. But the morbidity and mortality of this preventable disease remain an unacceptable fact. In this scoping review, we will revise the different treatment options and their indications.