Mimmo Roselli

Prevalence of epilepsy in rural Bolivia A door-to-door survey

Objective: To carry out a door-to-door survey in rural areas of the Cordillera Province, Santa Cruz Department, Bolivia, to determine the prevalence of neurologic diseases (epilepsy, stroke, parkinsonism, and peripheral neuropathy) in a sample of approximately 10,000 inhabitants. Methods: A team of nondoctor health workers administered a standard screening instrument for neurologic diseases—a slightly modified version of the World Health Organization protocol. All subjects found positive during the screening underwent a neurologic examination. Results: On screening, the authors found 1,130 positive subjects, of whom 1,027 were then investigated by neurologists. On the basis of the definition proposed by the International League Against Epilepsy, we detected 124 epileptic patients (prevalence, 12.3/1,000), 112 of whom had active epilepsy (prevalence, 11.1/1,000) on the prevalence day (November 1, 1994). Peak age-specific prevalence occurred in the 15 to 24-year age group (20.4/1,000). Sex-specific prevalence was higher in women (13.1/1,000) than men (11.4/1,000). Eighty-nine patients (71.8%) underwent a standard EEG recording. Considering both EEG and clinical data, partial seizures were the most common type (53.2%) based on the classification of the International League Against Epilepsy. The mean age at onset was 20.7 years for partial seizures and 13.6 years for generalized seizures. Only 10.5% of patients had received specific treatment for more than 2 months of their life. Conclusion: This report on epilepsy prevalence in Bolivia confirms that epilepsy is a major health problem in rural areas of developing countries.

Epilepsy, cysticercosis, and toxocariasis: a population-based case-control study in rural Bolivia.

Objective To assess the relationship between epilepsy and infection with Taenia solium and Toxocara canis with a case-control study, in the rural area of the Cordillera Province, Bolivia. Methods A preliminary two-phase door-to-door prevalence survey determined the prevalence of epilepsy and identified cases and control subjects. At least two control subjects per case were selected, matching on sex, age, and community of residence. Cases and control subjects were assessed serologically for antibodies against T. canis by ELISA and against T. solium by enzyme-linked immunoelectrotransfer blot (EITB). Results The prevalence survey found 130 confirmed cases of epilepsy, of which 113 were eligible for the case-control study (59 partial seizures and 54 generalized seizures). Two hundred thirty-three control subjects were selected. Multivariable analysis for a matched case-control study was carried out. There was an association between EITB positivity for T. solium and epilepsy with an OR of 1.85 (95% CI 0.99 to 3.4) for all cases. A stronger association was found in those with partial epilepsy with a late onset of disease (15 years and older), where the OR was 3.66 (95% CI 1.10 to 12.10). A positive association was also found with T. canis for all cases with an OR of 2.70 (95% CI 1.41 to 5.19). This increased for those with late-onset partial epilepsy to an OR of 18.22 (95% CI 2.10 to 158.10). Conclusion This finding suggests that both neurocysticercosis and toxocariasis may in part explain the higher prevalence of epilepsy, particularly partial epilepsy, in developing countries.

High Prevalence of Acquired Antimicrobial Resistance Unrelated to Heavy Antimicrobial Consumption

In a very remote rural Bolivian community where the use of antimicrobials has been minimal and where exchanges with the exterior are very limited, 67% of subjects were found to be carriers of fecal Escherichia coli with acquired resistance to >/=1 antimicrobial agent(s); the highest rates were observed for tetracycline (64%), ampicillin (58%), trimethoprim-sulfamethoxazole (50%), and chloramphenicol (41%). The most relevant implication of these findings is that, in certain settings, the spread and maintenance of antimicrobial resistance can occur, regardless of whether selective pressure generated by the use of antimicrobials is present.

Patterns of antimicrobial use and antimicrobial resistance among healthy children in Bolivia

Summary

Seroprevalence of varicella zoster and rubella antibodies among rural populations of the Chaco region, south-eastern Bolivia.

OBJECTIVE  To determine the seroprevalence of antibodies against varicella zoster virus (VZV) and rubella virus among the population of two rural areas, Camiri and Villa Montes, Chaco region, south‐eastern Bolivia.

Prevalence of antibodies against hepatitis A and E viruses among rural populations of the Chaco region, south‐eastern Bolivia

Summary We conducted a cross‐sectional study to determine the seroprevalence of antibodies against hepatitis A and hepatitis E viruses (HAV and HEV) in the population of two rural areas, Camiri and Villa Montes, of the Chaco region, south‐eastern Bolivia. HAV antibodies were detected in 461 (94.1%) of 490 serum samples tested, not differing significantly between sexes and study areas. The HAV seropositivity rate (64.7%) was high even in the youngest age group (1–5 years). The prevalence of HEV was 7.3%, with no significant differences between sexes. The prevalence of HEV antibodies in the population of the Camiri area (10.4%) was significantly higher than in the Villa Montes area (4.4.%), possibly due to the better quality of drinking water in the Villa Montes area. In the population ≤ 30 years of age, the HEV seropositivity rate (4.4%) was significantly lower than in the ≥ 31 year‐old group. This is consistent with findings in other countries. This is the first report of the prevalence of HEV infection in Bolivia.

A Neuroepidemiological Survey in Rural Bolivia: Background and Methods

A door-to-door survey was carried out in rural areas of the Cordillera province, Santa Cruz Department, Bolivia. A cluster sample of 10,124 inhabitants was selected. The aim was to determine the prevalence of the most common neurological diseases (epilepsy, stroke, parkinsonism and peripheral neuropathy) in this population using a modification of the World Health Organization screening instrument. 1,130 subjects screened positive and were then investigated by neurologists. In this paper we describe the background and methods of the survey and the characteristics of the population.

Prevalence of measles antibody among children under 15 years of age in Santa Cruz, Bolivia: implications for vaccination strategies

We conducted a community-based survey in Santa Cruz city, Bolivia, to determine the age-specific prevalence of measles antibodies, determine factors associated with absence of detectable measles antibodies, and to compare results of salivary and serum measles immunoglobulin G (IgG) antibody assays. Serum samples from 1654 children were assayed for measles IgG antibody using the haemagglutination inhibition (HI) assay, and salivary samples were also obtained from 187 children and tested for measles IgG antibody using an antibody capture radioimmunoassay. Reported measles vaccine coverage in children aged 12-35 months was 77% (95% confidence interval [CI], 72-81%). Eighty-seven percent (95% CI 85-89%) had detectable HI antibody, but a high proportion had antibody levels below 200 miu (30-40% of 2-14 years old children). Measles seronegativity was associated with not being vaccinated against measles, a negative history of measles disease, living in the inner city, being a lifetime resident of Santa Cruz, and young age. Of 212 children without detectable measles antibody, 58% had a positive history of vaccination or measles disease, so that historical information was not sufficiently reliable to identify susceptibles. The salivary measles antibody assay was not sufficiently sensitive to be used for population screening; only 54% of 171 salivary samples from children who had detectable serum HI antibody were positive. A mass measles vaccination campaign of all children under 15 years of age is planned in Bolivia in 1994. Although only 7% of school-age children in Santa Cruz were seronegative, the effectiveness of a mass campaign in this age group depends in part on the response to revaccination of children with low, but detectable, antibody levels.

Response to measles revaccination among Bolivian school-aged children

The response to measles revaccination was evaluated in 1994 among 202 Bolivian school-aged children whose antibody levels were below 200 miu (milli-international units) by haemagglutination inhibition (HI) in a large-scale serosurvey conducted in Santa Cruz one year earlier. Of the 202 revaccinated children, 164 (82%) had seroconverted between the 1993 serosurvey and the pre-revaccination blood sample. A measles outbreak occurred in Santa Cruz 6 months before the revaccination. Among the seroconvertors, only 6% gave a history of measles, and 15% a history of contact with a case of measles. All 20 children with undetectable HI antibody pre-revaccination, and all 6 children with levels below 100 miu, seroconverted after revaccination. The geometric mean titres by HI at 4 weeks after revaccination were 2018 miu (95% confidence limits [95% CL] 1143, 3564) and 398 miu (95% CL 254, 625) in the 2 groups, respectively. Six of 9 children with pre-revaccination antibody titres of 100-199 miu also seroconverted. No child demonstrated a measles-specific immunoglobulin M response. Among the 29 children who seroconverted and were followed up at one year after revaccination, 15(52%) showed a fourfold or greater decline in antibody levels, which in 8 fell to levels below 200 miu. This study confirmed the observation that revaccination is successful in producing an antibody response in children with low or undetectable pre-revaccination titres, but it also confirmed that vaccine-induced immunity wanes rapidly.

Anticuerpos contra Trichinella spiralis en la población rural de la provincia Cordillera, Bolivia

A seroepidemiological study was conducted to determine the prevalence of antibodies to Trichinella spiralis among rural residents of Cordillera province, Santa Cruz Department, Bolivia. Using the enzyme-linked immunosorbent assay (ELISA), 234 serum samples were examined, and antibodies were detected in seven of the samples (3%). The results document for the first time the presence of human infestation with Trichinella in Bolivia and suggest the need to strengthen trichinelosis surveillance in the municipal slaughterhouses, to prevent the clandestine slaughter of animals, and particularly to ensure that residents and meat producers in the area become aware of the dangers of this zoonosis.Se realizo un estudio seroepidemiologico para determinar la prevalencia de anticuerpos contra Trichinella spiralis en el area rural de la provincia Cordillera del Departamento de Santa Cruz en Bolivia. Se examinaron 234 muestras de suero mediante el ensayo de inmunoabsorcion enzimatica (ELISA) y se detectaron los anticuerpos en siete muestras (3%). Los resultados documentan por primera vez la presencia de infestacion humana por Trichinella en Bolivia y sugieren la necesidad de fortalecer la vigilancia sanitaria de la triquinosis en los mataderos municipales, impedir la faena clandestina de animales y, sobre todo, lograr que los productores y pobladores tomen conciencia de los peligros de esta zoonosis.