Introduction

Cysticercosis/Taeniasis is listed among the so called Neglected Tropical Diseases (NTD), which are a group of 17 diseases with distinct characteristics that thrive mainly among the poorest populations [1]. Even though one of the classical features of NTD is that they were restricted to tropical and subtropical areas [2], the phenomenon of international travel and migration make possible to observe these diseases in temperate areas such as Europe [3]. Epidemiological data indicate that in Europe we are currently observing the overlapping between autochthonous cases that are disappearing, and imported cases that are rising as a consequence of travels and migrations [4].

The management of cysticercosis, and especially of neurocysticercosis (NCC), the central nervous system localization of the disease, is challenging in contexts where the disease is not frequent and health care providers may be unaware of this condition, thus leading to diagnostic delay and mismanagement [4]. The aim of this study was to review the cases of cysticercosis observed in five Southern European tropical diseases centers and to compare the characteristic of pediatric (<15 years) and adult patients.

Materials and methods

This is a retrospective observational study on cases of NCC observed in five European centres located in 3 cities. The participating centres are the Centre for Tropical Diseases and the Paediatric department of Sacro Cuore-Don Calabria Hospital, Negrar (Italy), the Infectious and Tropical Diseases Unit, Azienda Ospedaliero-Universitaria Careggi (AOUC), Florence (Italy), the Department for International Adoptees and Immigrant Children, Infectious Diseases Unit, Meyer Pediatric Hospital, Florence (Italy) and the Hospital Clinic, Barcelona (Spain). All the five centres are infectious diseases centres with inpatient and outpatient facilities and services especially dedicated to the study and management of tropical diseases in non endemic context. The two pediatric centres offer a screening service for adopted children for several infectious diseases including a serological screening for cysticercosis as recommended by an Italian protocol [5].

Clinical records of all patients with a diagnosis of cysticercosis managed in the period 1980–2013 in everyone of the participating centres were retrospectively reviewed. The cases were retrieved with the help of clinical and lab logs which are routinely compiled in each centres. The diagnostic criteria proposed by Del Brutto et al. (Table 1, [6]) have been retrospectively applied to each case.

Table 1 Diagnostic criteria for neurocysticercosis according to Del Brutto et al. [6]
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Epidemiological and clinical data of each patient were extracted from the clinical records using an anonymized and standardized Epi Info™, version 3.5, 26th January, 2011. Differences in categorical variables between adult and pediatric cases were assessed using the Chi-square test (p values <0.05 were considered significant).

Results

Eighty-one subjects with cysticercosis were evaluated at the participating centers in the study period. All patients had central nervous system localization of cysticercosis, while extracerebral lesions were reported only in 1 patient. By applying Del Brutto’s criteria [6] to assess the degree of diagnostic certainty 39 cases (48.1 %) were classified as definitive cases, 31 (38.8 %) as probable cases and 11 (13.6 %) were deemed to be cases of NCC even if the diagnostic criteria were not fully satisfied. All patients underwent at least a brain imaging. In detail 4 (4.9 %) patients underwent CT scan only, 19 (23.4 %) MRI only and 58 (71.6 %) both MRI and CT scan. Table 2 reports the correlation between degree of diagnostic certainty, the number and type of cerebral lesions and the positivity of Enzyme-linked Immunoelectrotransfer Blot (EITB test) on serum. The number of diagnoses by period and continent of origin is reported in Fig. 1. Data on continent and country of origin are reported in Table 3.

Table 2 Correlation between the degree of diagnostic certainty according to the Del Brutto’s criteria, number and type of cerebral lesions and the positivity of Enzyme-linked Immunoelectrotransfer Blot on serum in patients with neurocysticercosis
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Fig. 1
figure 1

Number of subjects diagnosed with neurocysticercosis by continent of origin and year of diagnosis

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Table 3 Continent and country of origin of subjects with diagnosis of neurocysticercosis (data available for 80 subjects)
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Among the 14 European subjects, 7 patients had a relevant travel history to Latin America (3 cases), Sub-Saharan Africa (2), East European countries (1), or unknown country (1), while 7 cases were considered autochthonous infections acquired in Spain (n = 6) or Italy (n = 1). Among immigrants and adopted children, the time between the arrival in the host country and the admission for NCC was known in 58 cases. Of those, the majority (n = 32; 55.2 %) were admitted for NCC within 1–2 year after arrival, 12 (20.7 %) 3–5 years after arrival, 10 (17.2 %) 6–10 years after arrival and 4 (6.9 %) more than 11 after arrival (maximum delay 18 years).

Considering pediatric patients (n = 21), 10 (52.4 %) were males and mean age was 5.8 years (range 1–15 years). Among adult patients evaluated (n = 60), 23 (38.3 %) were males and mean age was 37.7 years (range 15–81 years). The mean age of European subjects without history of travel (n = 7) was 59.7 years (range 32–81 years). Nine pediatric patients (all asymptomatic and all adopted) were identified on the basis of a serological screening (EITB) and underwent subsequently to a brain MRI study showing lesions compatible with NCC.

Clinical features of patients are reported in Table 4.

Table 4 Clinical, serological and radiological features of subjects diagnosed with neurocysticercosis according to the age group (aged <15 years and aged ≥15 years)
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Discussion

The study shows several challenges related to the management of NCC in a non endemic area. In this multi-center study, 81 NCC cases were only retrieved in a 33 years period with a peak in the first part of years 2000’, probably due to the massive immigration from Latin American countries observed in that period [7].

The epidemiological characteristics of the patients can help to identify subjects with neurological signs or symptoms that could be affected by NCC. For example, as already reported [4], most NCC cases were imported from Latin America, although cases from every continent have been observed.

This study shows that there are some hurdles in the diagnostic process of NCC. A non negligible portion of patients (13.6 %) with a NCC diagnosis did not fully satisfy Del Brutto’s diagnostic criteria. Moreover, 5.5 % of patients underwent a biopsy-procedure, showing that non invasive tools are not sufficient to achieve the diagnosis of NCC or to rule out a CNS lesion of other origin. In our cases-series, specific serology with EITB method in which many clinicians rely for the diagnosis of NCC is shown to be poorly sensitive with a positivity rate of 70.1 % in cases with “definitive diagnosis”.

In our study pediatric patients were less likely to have symptoms. According to the literature there are several differences among children and adults NCC cases. First of all children are less frequently affected by NCC (Supplementary references a–c) probably due to mechanisms involved in disease acquisition and differences in the reactivity of the immune system against the parasite (Supplementary reference d). Autopsy series from several Mexico City hospitals report a lower prevalence in children if compared with adults (0.5 vs 2 %) [Supplementary references e, f] and asymptomatic NCC detected with MRI is found more often in subjects aged >15 years if compared with those aged <15 years (Supplementary reference b). If compared with children, adult patients with NCC have usually higher incidence of headache (Supplementary reference d), extraparenchimal NCC (Supplementary references d, g), raised intracranial pressure (Supplementary references d, g), altered cerebrospinal fluid findings (Supplementary references d), focal neurodeficits (Supplementary references g–i), depression syndrome (Supplementary references g, j) and seizure recurrence after anticonvulsivants discontinuation (Supplementary references g, k, l). On the other hand children have more frequently seizures (Supplementary reference d), single colloidal parenchymal cysts (Supplementary reference d).

The high portion of asymptomatic cases of NCC in children that we observed is probably related to the ongoing serological screening for cysticercosis among children adopted from endemic regions, which caused a not negligible number of “only” seropositive children to be evaluated for a possible NCC [5].

The screening for cysticercosis in asymptomatic subjects could be theoretically useful in people at risk for NCC in order to early intercept affected subjects and improve their management and clinical outcome. However, there is no clear evidence that treating an asymptomatic subject harboring a live parasite will reduce the probability of neurological symptoms in the future, so the usefulness of a serological screening is questionable.

In conclusion, this study suggest that NCC is a rare condition in Southern Europe, therefore it is not surprising that clinicians may be poorly experienced in the diagnosis and management of it. NCC should be included in the differential diagnosis of patients with neurological signs or symptoms, especially if coming from endemic countries. Available diagnostic tools are not sufficiently accurate in some cases and as a consequence, a definitive diagnosis based on Del Brutto’s criteria cannot always be reached. Moreover, the treatment should be tailored on a case-by-case basis. For this reason, European health care providers might benefit from a transfer of knowledge from colleagues working in endemic areas through the creation of international networks involving expert from endemic areas. The development of a consensus diagnostic procedures and therapeutic decisions would positively impact on the patient care in Europe.