Magnetic resonance imaging features of pathologically proven cerebral sparganosis

The serum IgG antibody level as a biomarker for clinical outcome in patients with cerebral sparganosis after treatment

Introduction

Cerebral sparganosis is a rare parasitic infection of the brain tissue. The remission of MRI change and clinical symptom has been used to evaluate the therapeutic effect. However, there is no study to correlate the serum IgG antibody level of sparganum to the prognosis of disease after treatment.

Methods

87 patients with cerebral sparganosis were collected from three medical centers. Clinical symptoms and MRI changes were evaluated at 12 months after initial treatment, and serum IgG antibody level of sparganum was evaluated at 2, 6, and 12 months after treatment. The positive cut-off value was based on 2.1 times the optical density (OD) of negative control. The index value was defined as the sample OD divided by the cut-off value.

Results

Among the 87 patients after treatment, 71 patients had good clinical outcomes, and 16 had poor clinical outcomes. The area under the curve (AUC) showed that the index value measured at 12 months after treatment had the best prediction effect, with a value of 2.014. In the good-outcome group, the index values were less than 2.014 in all 71 patients, and only 8 patients had mildly enhanced residual lesions on MRI. In the poor-outcome group, the index values were more than 2.014 in all 16 patients, and all patients still showed significantly enhanced lesions on MRI. Compared with poor-outcome patients, only 2 patients with good outcomes had disease recurrence after treatment.

Discussion

This study provided evidence that the serum IgG antibody level of sparganum was a promising biomarker to evaluate the prognosis of patients with cerebral sparganosis after treatment.

Low prevalence of spargana infection in farmed frogs in the Yangtze River Delta of China

Frogs are the main source of infection for human sparganosis. In this study, the prevalence and pathogenicity of plerocercoid larvae (sparganum) in frogs collected from the Yangtze River Delta in East China were investigated. A total of 386 frogs belonging to five species were purchased from farmers' markets across all three provincial level areas in the Yangtze River Delta region. The overall prevalence was 4.9% (19/386), and 39 spargana were detected visually, with the intensity ranging from 1 to 11. The spargana infection rate was 7.7% (11/143) in Jiangsu Province and 4.4% (8/181) in Shanghai City, while no spargana infection was detected in Zhejiang Province. In five tested frog species, only Rana nigromaculata and R. limnocharis were found to harbor spargana infection, with a prevalence of 7.7% (13/168) and 6.3% (6/95), respectively. There was no significant difference among the months of the experimental period, July to September. The spargana mostly parasitized the muscle tissues of frogs, especially in the hind legs. All the spargana were identified by molecular analysis based on cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes, and all plerocercoids were Spirometra erinaceieuropaei. Nine mice were infected orally with 1 to 3 scoleces, and 77.8% (14/18) of plerocercoids were found in mice at the 30th day post infection. No obvious clinical symptoms were observed in the mice; however, histopathological analysis showed an inflammatory cellular response in all tissues except intestinal tissue. Hematologic analysis showed an increased number of white blood cells (WBCs) at the 18th day post infection. These results indicated that R. nigromaculata and R. limnocharis are a potential source of zoonotic sparganosis in the Yangtze River Delta of China, and farmed frogs may substantially reduce zoonotic risk as compared to eating wild frogs. Our findings will provide data for frog food safety and prevention and control of sparganosis in the region.

Efficacy comparison between long-term high-dose praziquantel and surgical therapy for cerebral sparganosis: A multicenter retrospective cohort study

Background

Sparganosis is a parasitic infection caused by the plerocercoid larvae of Spirometra mansoni in East and Southeast Asia. The plerocercoid larvae sometimes invade the encephalon, resulting in severe cerebral sparganosis. Surgical removal of the larvae is considered a standard therapy for cerebral sparganosis. In contrast, the efficacy and safety of long-term, high-dose praziquantel treatment for cerebral sparganosis have not been explored.

Methodology/Principal findings

In this multicenter retrospective study, we assessed the records of 96 patients with cerebral sparganosis who consulted at three medical centers from 2013 to 2017. Forty-two patients underwent surgical lesion removal, and the other 54 patients received long-term, high-dose praziquantel (50 mg/kg/day for 10 days, repeated at monthly intervals). The primary outcome was the complete disappearance of active lesions on cerebral magnetic resonance imaging. The secondary outcomes included the modified Rankin scale score at 90 days, incidence of seizure, eosinophil count, and serological Spirometra. mansoni antibody titer. The efficacy of praziquantel treatment was similar to that of surgical lesion removal for cerebral sparganosis with respect to both the primary outcome and secondary outcomes. Although binary logistic regression models also supported the primary outcome after adjustment for age, sex, lesion location, and loss to follow-up, some unavoidable confounders might have biased the statistical power. No significant clinical complications or laboratory side effects occurred in the praziquantel group with the exception of a relatively benign allergic reaction.

Conclusions/Significance

In this small-sample, nonrandomized, retrospective exploratory study, some patients with cerebral sparganosis were responsive to long-term, high-dose praziquantel with an efficacy similar to that of surgical lesion removal. These findings increase the treatment flexibility for this serious infection.

Sparganosis is most prevalent in developing countries in East and Southeast Asia, probably because public health strategies have not prioritized its prevention. The plerocercoid larvae of Spirometra mansoni sometimes invade the brain parenchyma, resulting in cerebral sparganosis. In general, surgical removal of the larvae is considered a standard therapy for cerebral sparganosis. One alternative treatment for sparganosis is short-term, low-dose praziquantel, which has had limited success. However, the efficacy and safety of long-term, high-dose praziquantel treatment for cerebral sparganosis have not been explored. In this study, we evaluated the effectiveness of long-term, high-dose praziquantel for treatment of cerebral sparganosis in China. We conducted a retrospective exploratory study using routinely recorded data from 96 patients at three medical centers. Forty-two patients underwent surgical lesion removal, and the other 54 patients received long-term, high-dose praziquantel. Treatment of cerebral sparganosis by long-term, high-dose praziquantel showed an efficacy similar to that of surgical lesion removal with respect to the primary outcome (complete disappearance of the active lesions on cerebral magnetic resonance imaging). However, this was a small-sample, nonrandomized retrospective study, and the results should be further confirmed by a large-sample prospective study or other studies.