Epidemiology of Taeniasis and Cysticercosis in a Peruvian Village

Abstract

To determine the prevalence of cysticercosis in a rural area where the disease is endemic, the authors studied the seroepidemiology of human and porcine cysticercosis in a Peruvian jungle community (Maceda, Peru) in 1988 using an enzyme-linked immunoelectrotransfer blot (EITB) assay. Of the 371 sampled inhabitants, 30 (8%) were seropositive, most of whom were asymptomatic. After niclosamide therapy, four Taenia species worms were identified in the seropositive group, compared with one in the control group (p = 0.06). Pigs were frequently infected: 44 of 133 (33%) were found positive for Taenia by tongue examination and 57 of 133 (43%) were positive by EITB. In 69% of the sampled households that had pigs, there was at least one seropositive pig. The number of pigs diagnosed positive by the tongue examination was significantly greater in households that had latrines than in those that did not. Cysticercosis is a common but usually asymptomatic infection that affects both humans and pigs in the high jungle areas of Peru. Keywords cysticercosis; environmental monitoring; immunoblotting; swine; Taenia; toilet facilities; transfer blot Cysticercosis is a disease endemic in most developing countries where pigs are raised (1). In both Mexico and Peru, more than 10 percent of neurologic patients receiving acute care have serologic evidence of Taenia solium infection (2, 3). Humans acquire cysticercosis by ingesting T. solium eggs from human feces either directly or indirectly, through contaminated food or water. The eggs mature into larvae, which invade the intestinal wall, Copyright © 1992 Europe PMC Funders Author ManuscriptsEurope PMC Funders Author Manuscripts muscle, brain, and other tissues. Pigs also acquire cysticercosis in the same manner. Humans develop taeniasis after ingesting raw or poorly cooked pork or beef that contains the larval form of T. solium or Taenia saginata. Larvae invaginate the small intestine of humans and develop into adult tapeworms. The tapeworm produces eggs after 3 months and may survive for years, thus spreading cysticercosis in both humans and pigs (4, pages 609-25).Rational programs to control cysticercosis cannot be developed until the epidemiology of the disease is better understood. The true incidence of cysticercosis in both human and pig populations is unknown. The prevalence of porcine infection, based on meat inspections in Mexican slaughterhouses, has been estimated at 0.005-10 percent (5). However, many infected pigs are raised by small farmers, who often sell their pigs in informal markets where meat inspection is not performed. Since governmental and international agencies base their statistics for porcine cysticercosis on slaughterhouse statistics (6, 7), clandestine sale of meat results in a considerable underestimation of the true prevalence rates of porcine cysticercosis. For example, in Huancayo, a city of 500,000 inhabitants in the highlands of Peru, no pigs were registered as infected with cysticercosis (8), yet field surveys revealed that more than 30 per...

Increased prevalence of cysticercosis and taeniasis among professional fried pork vendors and the general population of a village in the Peruvian highlands. Cysticercosis Working Group in Peru.

“…Although similar overall seroprevalences were found among chicharronneros and general villagers, chicharroneros had more significant disease than did general villagers. In addition, the high rate of T. solium tapeworm infection in this village, at least 3% (17%, demonstrated by antiparasitic treatment in the seropositive individuals), which is 4-8 times higher than usual, [10][11][12]15 suggests that viable cysts were in-gested more frequently than that which occurs in most endemic villages. The 3% prevalence rate for taeniasis is based on the assumption that all seronegative individuals did not have a tapeworm.…”

“…Domestic pig raising with poor animal husbandry 5 is by far the most important of these factors. [9][10][11] The risks associated with this activity, however, are difficult to estimate because of confluent factors that include poor sanitary conditions, and poor knowledge of the parasite life cycle, resulting in sustained consumption of infested pork. 12 This study, performed in a cysticercosis-endemic zone, demonstrates that food handlers who specialize in pork preparation are especially at risk for infection with both T. solium intestinal tapeworms as well as larval tissue cysts (cysticercosis).…”

The emergence of Taenia solium cysticercosis in Eastern and Southern Africa as a serious agricultural problem and public health risk

“…The high prevalence of cysticercosis in pigs strongly suggests that many people are carriers of the pig tapeworm and consequently contaminate their direct environment with eggs containing oncospheres that are infective for both humans and pigs, thereby maintaining the life cycle. In regions where cysticercosis in pigs is common, human cysticercosis and epilepsy prevalence are also usually high as shown by results from other endemic areas in Latin America and other African countries (Diaz et al, 1992;Newell et al, 1997;Sciutto et al, 2000). Therefore, there is an urgent need to collect baseline data on human cysticercosis and its possible linkage with epilepsy in the ESA region for a better understanding of the local epidemiology and transmission risks.…”

Taeniasis-cysticercosis in Southern Ecuador: assessment of infection status using multiple laboratory diagnostic tools

“…Gonzalez et al 1990, Diaz et al 1992, Garcia Noval et al 1996, Sanchez et al 1997, Goodman et al 1999, Garcia et al 2003, Cruz-Licea et al 2003, PrestesCarneiro et al 2006. Both methods attempt to measure the proportion of infected individuals, however, antigen detection is restricted to the detection of viable cysticerci, while the finding of antibodies can indicate the presence of both viable and degenerated cysticerci or past infection (Dorny et al 2004a).…”