An epidemiological study of epilepsy and epileptic seizures in two rural Guatemalan communities.

A cross-sectional epidemiological study of two communities in Guatemala, El Jocote and Quesada, was conducted to determine the prevalence of epilepsy and epileptic seizures. An initial screening questionnaire was applied to detect individuals who had possibly suffered seizures in the past. These individuals were then examined more thoroughly by a neurologist, to confirm or reject them as cases of epilepsy. The crude prevalences of epilepsy so revealed were 28 cases/1000 in El Jocote and 29 cases/1000 in Quesada. The prevalence of active epilepsy in each community was approximately 18 cases/thousand. The most common type of seizure suffered was of the generalised tonic--clonic type. Seventy-six of the individuals who had a history of epileptic seizures and 51 individuals from the same communities with no such history were then given brain scans, using computerized axial tomography. These neuro-imaging studies revealed some form of abnormal image in 33% (17) of the subjects with no history of seizures and 70% (53) of those with a history of seizures (chi(2) = 12.2; P < 0.00006). The frequency of detected brain abnormalities in the individuals who had suffered a single episode of seizures was similar to that in those who were classified as epileptic. The most commonly observed type of abnormality was punctate calcification, followed by cerebral oedema and hypodensities. The reasons for the high prevalences of epilepsy, epileptic seizures and abnormal neuro-images observed in the present study merit further investigation. Although neurocysticercosis caused by Taenia solium was thought to be a significant cause of the epilepsy occurring in the study communities, many apparently non-epileptic individuals have brain lesions indicative of this disease.

Mass chemotherapy for intestinal Taenia solium infection: effect on prevalence in humans and pigs.

Mass treatment of the human population with niclosamide was carried out in 2 villages in rural Guatemala where Taenia solium was endemic, to determine how this would affect the epidemiology of the parasite. Intestinal taeniasis was diagnosed by microscopy and coproantigen testing, and porcine cysticercosis by a specific Western blot. Before mass treatment, the prevalence of human taeniasis was 3.5%; 10 months after treatment it was 1%, a significant decrease (P < 10(-4)). All tapeworms that could be identified to the species level were T. solium. Similarly, the seroprevalence of antibodies to cysticercosis in pigs declined from 55% before treatment to 7% 10 months after treatment, once again a significant decrease (P < 10(-6)). These effects were seen in both villages. The possible use of mass chemotherapy as a tool in the control of T. solium is discussed.

Epidemiology of Taenia solium taeniasis and cysticercosis in two rural Guatemalan communities.

Taenia solium taeniasis and cysticercosis are known to be endemic in Guatemala but no studies had been undertaken in rural communities where transmission was thought to occur. Two adjacent communities, Quesada and El Jocote, in the Department of Jutiapa were selected. The former had considerably better sanitary infrastructure than the latter. The seroprevalence of antibodies detected in humans by immunoblot to T. solium metacestode glycoprotein antigens was 10% and 17% and the prevalence of intestinal taeniasis was 1% and 2.8% in the two villages, respectively. Both of these represented statistically greater rates in El Jocote. Females were significantly more likely to be seropositive than males in the study as a whole. The majority of cases of intestinal taeniasis were due to T. solium. Cases of intestinal taeniasis were significantly more likely to be anti-cysticercus antibody-positive than the general population. Epilepsy was recorded in 2.8% and 2.9% of the populations of Quesada and El Jocote, respectively. Follow-up of this group and a group of asymptomatic individuals by computed tomography scan indicated that individuals with a history of seizures had a higher rate of abnormalities suggestive of neurocysticercosis. Cysts were present in the tongues of 4% of live pigs sampled in Quesada and 14% in El Jocote. In these two communities, which are probably representative of many others in Guatemala, T. solium appeared to be a significant public health problem.

Coproantigen detection for immunodiagnosis of echinococcosis and taeniasis in dogs and humans.

Three ELISA assays, based on hyperimmune rabbit serum raised against adult cestode somatic antigen, were applied in this study for the detection of Taenia- and Echinococcus-specific antigens in host faeces. The first assay, using an antiserum against Taenia pisiformis antigen extract, was used in a time-course of T. pisiformis experimental infection in dogs. The assay was shown to be considerably more sensitive than microscopical detection of eggs in faeces. Antigen was present in faeces before patency and antigen levels were independent of T. pisiformis egg output. The second assay, involving a test for human taeniasis based on antibodies against T. solium, was applied in two field studies carried out in China and Guatemala. The test was highly specific, no false positive reactions occurred with human faecal samples and the test was capable of diagnosing individuals who would not have been detected by coproscopy or treatment to recover the tapeworm. A third assay was designed for E. granulosus and demonstrated 87.5% sensitivity and 96.5% specificity with samples from naturally and experimentally infected dogs with Echinococcus or Taenia infections. In both the human Taenia and canine Echinococcus studies antigen could be detected in faecal samples from infected hosts stored in 5% formalin for 6 months. Further refinements to these tests for field application are discussed.