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.

Human cystic echinococcosis in a Uruguayan community: a sonographic, serologic, and epidemiologic study.

A prevalence and transmission study of human cystic echinococcosis (CE), due to infection with the dog tapeworm Echinococcus granulosus, was undertaken in the village of La Paloma in central Uruguay. The human population was registered and screened for CE by abdominal ultrasound scan as well as a number of serologic tests. Dogs were screened for E. granulosus infection by arecoline purgation as well as specific coproantigen testing. The total prevalence of human CE (new cases and those with a previous history) was 5.6% (64 of 1,149); 3.6% (40) of the cases were new ultrasound detected asymptomatic cases (mean age = 45 years). Age prevalence increased from 1.1% in the 4-6-year-old group to > 11% in the > 60-year-old group; the 20-29-year-old group had a significantly higher CE rate of 7.4%, compared with younger and older age groups, and there was no difference between sexes. A CE rate of 3.9% (20 of 514) was also recorded by ultrasound for new cases in the population residing outside the village. Most of the hydatid cysts were located in the liver presenting as either univesicular cysts or a solid mass, and of those 71% and 63%, respectively, with such cyst presentations were seropositive against E. granulosus cyst fluid antigens. Two of eight individuals who were filter paper blood spot seropositive, but ultrasound scan negative, were subsequently diagnosed respectively with pulmonary hydatidosis after radiography, and hepatic hydatidosis after computed tomography scan. Of 36 households with a CE patient, 32 were single cases while four households each harbored two CE cases. This did not represent a clustered distribution within families (23 of 117). Almost 20% of the dogs from La Paloma were found infected with E. granulosus after purge examination, with a mean worm number of 67 (range = 1-1,020). An additional eight dogs that were purge negative were Echinococcus coproantigen positive. The study showed that human CE is highly endemic in Uruguay, with one of the highest local prevalence rates in the world. Transmission appears to occur readily within well-developed towns, as well as on rural sheep ranches. Mass screening by ultrasound scanning with confirmatory serologic testing is an effective approach to case detection at the community level.

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.

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.

Epidemiology of intestinal taeniasis in four, rural, Guatemalan communities.

There is relatively little epidemiological information on human intestinal taeniasis, particularly that due to Taenia solium. The current study involved analysis of data collected from four, rural communities in the Department of Jutiapa, Guatemala, between 1991 and 1994. Overall, 92 cases of intestinal taeniasis were identified, giving a mean prevalence of 2.7% (92/3399). Almost all (98%) of the 56 worms identified to species level were T. solium. Female subjects were significantly more likely to be infected than males, with a relative risk of 1.21 (95% confidence interval = 1.04-1.42; P < 0.04). Mean prevalence rose with age until the 30-39-year age cohort and declined thereafter. Cases were significantly clustered in households (P < 0.001). Most infections appeared to correspond to single worms. Only one multiple-worm infection was definitely detected, in an individual with at least seven T. solium tapeworms, all of which appeared to be sexually immature. To determine potential movements of infected subjects out of the villages, adult subjects in two of the villages were asked about their main place of employment; 9.7% (94/968) were recorded as working either in Guatemala City or the U.S.A. The possible epidemiological implications of these findings are discussed.