Changing pattern of neurocysticercosis in an urban endemic center (Guayaquil, Ecuador)

doi:10.1016/j.jns.2011.11.034

Journal of the Neurological Sciences

Volume 315, Issues 1–2, 15 April 2012, Pages 64-66

https://doi.org/10.1016/j.jns.2011.11.034 Get rights and content

Abstract

Objective

To confirm recent evidence suggesting a change in the pattern of disease expression of neurocysticercosis, manifested by a decreasing number of severe and recent infections.

Methods

Retrospective cohort of 246 neurocysticercosis patients residing in Guayaquil, evaluated over 20 years (1990 to 2009). Eighty-seven patients were seen from 1990 to 1994, 58 from 1995 to 1999, 57 from 2000 to 2004, and 44 from 2005 to 2009. Neurocysticercosis was classified as active or inactive according to neuroimaging findings. Patients with parenchymal, subarachnoid or ventricular cystic lesions were considered to have active disease, and those with calcifications and chronic arachnoiditis were classified as inactive.

Results

Mean age was 36.6 ± 20 years, and 61% were women. The relative prevalence of active and inactive cases varied according to the year of evaluation. Active neurocysticercosis was found in 63% of patients seen between 1990 and 1994, in 48% between 1995 and 1999, in 47% between 2000 and 2004, and in only 18% between 2005 and 2009 (p < 0.0001). Together with reduction of active cases, there was an increased prevalence of asymptomatic infections over the years (from 17.2% between 1990 and 1994 to 54.5% between 2005 and 2009; p < 0.0001).

Conclusion

In this single-center cohort, the relative prevalence of active cases of neurocysticercosis reduced over the past years, suggesting a decreased incidence of new infections. Improved sanitation together with widespread use of cysticidal drugs were the most likely causes of these findings.

Introduction

Neurocysticercosis is a major public health problem in the developing world, and a leading cause of acquired epilepsy worldwide [1]. Disease burden varies according to several factors, including the socio-economic status of the population, the level of sanitation, and the degree of awareness on the mechanisms of disease acquisition [2].

It has been suggested that widespread use of cysticidal drugs together with improved sanitation and increased public awareness on the disease, could have cause a recent decrease in the number of severe cases of neurocysticercosis or even a reduction in its prevalence [3], [4]. To test this hypothesis, we conducted a retrospective cohort study of patients with neurocysticercosis evaluated at our institution over a 20-year period. The pattern of disease expression of neurocysticercosis, i.e., the relative prevalence of active vs inactive cases, may be a reflection of the incidence of this parasitic disease in a given population. We review our patients to see if there was any change in the pattern of disease expression suggesting a decrease in the number of active “recent” infections.

Section snippets

Patients and methods

From January 1990 to December 2009, 331 consecutive patients with newly diagnosed neurocysticercosis were evaluated by one of us (O.H.D.) at the Department of Neurological Sciences, Hospital-Clínica Kennedy, Guayaquil, Ecuador. Those patients had not received therapy with cysticidal drugs prior to their first visit to the clinic. Our institution is the largest center of private medicine in the city, serving people of middle and high socioeconomic status and, due to a number of agreements with

Results

Ninety-six of the 246 included patients (39%) were men and 150 (61%) were women, with a mean age of 36.6 ± 20 years (age range, 2 to 87 years). Eighty-seven patients (35%) were seen from 1990 to 1994, 58 (24%) from 1995 to 1999, 57 (23%) from 2000 to 2004, and 44 (18%) from 2005 to 2009. As a whole, 155 patients (63%) belonged to the middle and high socioeconomic status, and the remaining 91 patients were of the low economic income class. There were no significant differences in the demographic

Discussion

Our retrospective cohort of patients with neurocysticercosis showed that the relative prevalence of active cases has significantly changed during the past few years, suggesting that the incidence of new infections has been reduced, as calcifications and chronic arachnoiditis represent old infections that most likely occurred a number of years ago. Together with other studies, results from our series shows that more severe cases of neurocysticercosis are less frequent now than they were 10 years

Conflict of interest

Nothing to disclose.

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Cited by (10)

Neurocysticercosis
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Citation Excerpt :
Control interventions include treatment of adult tapeworm carriers (either directed, after diagnosis, or through mass chemotherapy programs), treatment of infected pigs, and pig immunization (Keilbach et al., 1989; Garcia et al., 2006, 2007; Lightowlers, 2010). Recent reports describing less frequent NCC cases in Mexico and a changing pattern of NCC in an urban center of an endemic area in Ecuador, suggests that improved sanitation may be a main factor to reduce the occurrence of severe and recent infections (Flisser and Correa, 2010; Del Brutto and Del Brutto, 2012). The availability of an efficacious vaccine for pigs (TSOL18, developed at the University of Melbourne in Australia) (Flisser et al., 2004; Gonzalez et al., 2005) and a single-dose treatment for infected pigs (oxfendazole, first used in 1996 for this purpose) (Gonzalez et al., 1996) increase the hope for focal elimination.
Cysticercosis, an infection caused by the cystic larvae of the pork tapeworm Taenia solium, is one of the most frequent parasitic infections of the human nervous system (neurocysticercosis). It is endemic in most of Latin America, the sub-Saharan Africa, and vast parts of Asia, including the Indian subcontinent. It has also been increasingly diagnosed in developed countries because of migration of people from endemic zones and exposure in travelers. The life cycle involves the development of the adult tapeworm in the human small intestine (after ingesting infected pork with cysts) and larval infection in pig tissues (after ingesting human stools containing the eggs of the tapeworm). Humans get infected by the fecal-oral route, most often from a direct contact with an asymptomatic Taenia carrier. Most common clinical presentations are seizures (particularly late-onset seizures), chronic headaches, and intracranial hypertension. However, cysticerci can locate anywhere in the human nervous system, thus potentially causing almost any neurological syndrome and making clinical diagnosis a difficult task. Neuroimaging is the main diagnostic tool, and specific serology confirms the diagnosis and helps to define the diagnosis when images are unclear. Factors such as location (extraparenchymal versus intraparenchymal), number, size and evolutive stage of the parasites determine the clinical manifestations, therapeutic approach, and prognosis. Management includes symptomatic drugs (analgesics, antiepileptic drugs, anti-inflammatory agents) and in many cases cysticidal drugs, either albendazole or praziquantel. In recent years, efforts have focused on transmission control and potential elimination in endemic regions.
Reduced percentage of neurocysticercosis cases among patients with late-onset epilepsy in the new millennium
2012, Clinical Neurology and Neurosurgery
Citation Excerpt :
Moreover, this is the only reported large-scale cohort of patients with late-onset epilepsy evaluated over two decades. In urban centers of developing countries, two main factors may be responsible for the reported drop in the number of patients with symptomatic NCC [16]. On one side is the increased number of houses with better facilities such as piped water and proper sewage disposal [11].
To determine if the number of neurocysticercosis cases among patients with late-onset epilepsy has decreased over the past two decades.
Retrospective cohort study of 431 consecutive patients with recurrent seizures starting after the age of 20 years evaluated at our Institution from 1990 to 2009.
Patients were classified according to the year in which they were first seen. Group I included 129 patients evaluated between 1990 and 1994, Group II included 108 patients evaluated between 1995 and 1999, Group III included 106 patients evaluated between 2000 and 2004, and Group IV included 88 patients evaluated between 2005 and 2009. We correlated the percentage of persons with cryptogenic and symptomatic epilepsy between the groups to determine if there was any change in the causes of late-onset epilepsy.
One hundred seventy-one patients had cryptogenic and 260 had symptomatic epilepsy. Common causes of symptomatic epilepsy were neurocysticercosis in 120 cases, cerebrovascular disease in 68, and brain tumors in 40. We found a reduction in the number of patients with symptomatic epilepsy (p = 0.0007) as well as a reduction in the number of neurocysticercosis cases (p = 0.0004) over the study years. There was a reduction in the weight of neurocysticercosis as an etiological factor for symptomatic late-onset epilepsy related to a drop in the number of patients with this condition evaluated between 2005 and 2009 (p = 0.0045).
The number of neurocysticercosis cases among patients with late-onset epilepsy has changed over the years. This parasitic disease is no longer the most common cause of symptomatic late-onset epilepsy in our population.
Control of taenia solium taeniasis/cysticercosis: Past practices and new possibilities
2013, Parasitology
Parasitoses of the human central nervous system
2013, Journal of Helminthology
The leptomeninges as a critical organ for normal CNS development and function: First patient and public involved systematic review of arachnoiditis (chronic meningitis)
2022, PLoS ONE
Spontaneously arrested transmission of cysticercosis in a highly endemic village with a very low migration rate
2018, American Journal of Tropical Medicine and Hygiene

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¹: Design of the study and drafting of the manuscript.

²: Design of the study and analysis of data.

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Changing pattern of neurocysticercosis in an urban endemic center (Guayaquil, Ecuador)

Abstract

Objective

Methods

Results

Conclusion

Introduction

Section snippets

Patients and methods

Results

Discussion

Conflict of interest

Lancet Neurol

J Neurol Sci

Arch Med Res

Acta Trop

Neurocysticercosis may no longer be a public health problem in Mexico

PLoS Negl Trop Dis