Rattus norvegicus como indicador de la circulación de Capillaria hepatica y Taenia taeniaeformis en la Plaza Minorista de Medellín, Colombia / Rattus norvegicus as an indicator of circulation of Capillaria hepatica and Taenia taeniaeformis on a groceries trade center of Medellín, Colombia

Introducción. Rattus norvegicus cumple un papel epidemiológico en el mantenimiento y dispersión de agentes zoonóticos bacterianos, virales y parasitarios de interés en salud pública. La presencia de infección por helmintos en especies Rattus cercanas a poblaciones expuestas en condiciones ambientales propicias, puede convertirse en un factor de riesgo de transmisión. Objetivo. Reportar la frecuencia de infección con Capillaria hepatica y formas larvarias de Taenia taeniaeformis en ratas silvestres (R. norvegicus) capturadas en una zona urbana de Medellín. Materiales y métodos. Se capturaron 254 ejemplares de R. norvegicus. Los hígados de 54 ejemplares que presentaron lesión hepática macroscópica durante la necropsia, fueron examinados por histopatología convencional. Resultados. La frecuencia de infección por C. hepatica fue de 20,1 % (51/254). Seis hígados fueron también positivos para larvas de T. taeniaeformis con una frecuencia de 2,4 % (6/254). Los hígados infestados con C. hepatica exhibían parásitos en el estadio adulto o juvenil y huevos ovalados con opérculos bipolares, asociados con hepatitis granulomatosa leve a moderada multifocal y acompañada por infiltrado leucocitario. Se observaron lesiones granulomatosas en resolución y fibrosis residual o calcificada que contenía huevos. Donde se encontraron cisticercos de T. taeniaeformis, el hallazgo más frecuente fueron quistes hepáticos que contenían larvas, y lesiones inflamatorias y fibróticas. Conclusión. Estos resultados indican que helmintos de potencial zoonótico circulan en R. norvegicus de ambientes urbanos. Debe investigarse la verdadera distribución de estos parásitos, para determinar el riesgo potencial que corren las poblaciones animales y humanas expuestas a adquirir este tipo de infecciones.

Introduction. Rattus norvegicus, the Norway rat, plays a pivotal role in the maintenance and spread of several zoonotic bacterial, viral and parasitic pathogens of public health interest. The presence of helminthic infections near susceptible human populations can, under appropriate environmental conditions, become a risk factor for their transmission. Objective. Frequencies of infection were reported for Capillaria hepatica and larval forms of Taenia taeniaeformis in wild rats (R. norvegicus) captured in an urban area. Materials and methods. Two hundred and fifty-four adult specimens of R. norvegicus were collected in an urban zone of Medellín, Colombia. The livers of 54 specimens that showed macroscopic hepatic lesions during necropsy were examined by conventional histopathology. Results. The frequency of infestation with C. hepatica was 20.1% (51/254). Six livers (2.4%) were also positive for larvae of T. taeniaeformis. Livers infested with C. hepatica exhibited adult or juvenile parasites and oval eggs with bipolar opercula, and were associated with mild to moderate multifocal granulomatous hepatitis with leucocyte infiltrate. Granulomatous lesions and calcified residual fibroses were found with eggs but without adult parasites. Those animals with cysticerci of T. taeniaeformis showed a high frequency of hepatic cysts containing larvae as well as inflammed and fibrotic lesions. Conclusion. Zoonotic helminths circulate at high frequency in R. norvegicus that occur in urban environments. Further research about the distribution of these parasites will determine the level of health threat they present for susceptible human and domestic animal populations.

Tratamiento de la neurocisticercosis: revisión critica / Treatment of neurocysticercosis: a review

Neurocysticercosis (NCC) is the most common parasitic disease of the central nervous system. Several drugs, such as drugs against tapeworms, praziquantel or albendazole associated to corticosteroids, have been tested for the treatment of this condition. Although some have claimed the reduction or involution of cystic or granulomatous lesions, there is no consensus about the efficacy of these treatments. The natural evolution of the disease is not clear and this hampers the assessment of treatment effects. Moreover, there are no good imaging or clinical indicators that can predict the progression or spontaneous resolution of lesions, specially at the meningeal or ventricular compartment. Therefore, evidence based medicine does not have a definitive answer about the treatment, neither of seizures, the most common manifestation of NCC, or the varied and complex meningeal and ventricular involvement. This review includes experts opinions to give the clinician some clues for decision making in the treatment of NCC.

Cysticercosis in Indonesia: epidemiological aspects.

Cysticercosis caused by the larval stage, cysticercus or cysticerci, of the pork tapeworm Taenia solium was recognized at first in Bali and in Paniai District, Irian Jaya (Papua), Indonesia in the 1970s. In the 1990s a rapid increase in the number of the cases of epileptic seizures and burns in Jayawijaya district, eastern Papua, was observed. There were a total of 1,120 new cases of burns (7.0%) and 293 new cases of epileptic seizures (1.8%) from 15,939 local people during 1991-1995. Both histopathological examination and mitochondrial DNA analysis of resected cysts from patients and pigs revealed cysticerci of T. solium. Antibody responses highly specific to cysticercosis were revealed in approximately 67% and 65% of persons respectively with epileptic seizures and with subcutaneous nodules. Therefore, most cases of epileptic seizures and burns were considered to be associated with cysticercosis in Papua. Additional serologically data from Bali showed that 13.5% of epileptic seizures (10/74) and 12.6% of asymptomatic individuals (94/746) were supposed having been exposed to T. solium. Histopathological evaluation of 80,000 tissue samples in East Java revealed that nine were cysticercosis. All cases were non-moslems and from two ethnic groups, Chinese and Balinese. Epidemiological data on cysticercosis are not available from other provinces of Indonesia, although cases of cysticercosis are occasionally reported. Therefore, other intensive epidemiological studies are strongly recommended, especially covering the eastern part of Indonesia.

Controlling Taenia solium in Nepal using the PRECEDE-PROCEED model.

Taenia solium is a predominant food-borne parasitic zoonosis (FBPZ) in Nepal. Using the PRECEDE framework, as defined by Green and Kreuter, we can identify the factors behind the high incidence of this disease. Armed with this information, we can define the actions necessary to control T. solium. In accordance with the first step of PRECEDE, social assessment, we set the goal of decreasing the potential for T. solium transmission in Nepal by the year 2003. This goal has yet to be endorsed by policy makers. However, an epidemiological assessment based on hospital data alone showed that T. solium is an endemic problem in urban Nepal that must be addressed. Based on behavioral and environmental assessments (Steps 1 and 2 of PRECEDE-PROCEED), we defined the following action objectives to be achieved by 2003: 1) Train meat producers and sellers to detect contaminated pork and avoid selling it, 2) Improve pig husbandry to limit the animals' access to human feces, 3) Construct hygienic model slaughterhouses. These improvements could control the meat-producing environment, thus limiting the potential for cross-carcass contamination and other hygiene deficiencies associated with the spread of T. solium. An educational and ecological assessment shows all predisposing, reinforcing and enabling factors are present in Nepal, consistent with PRECEDE requirements. While T. solium is clearly defined as a health problem according to PRECEDE, there remain significant hurdles to controlling it. These hurdles lie in administration and policy, where standardized law-enforcement and meat inspection practices are needed. Finally, the government of Nepal must assign high priority to T. solium control, as it is a preventable, yet prevalent disease.

Control of Taenia solium taeniasis and cysticercosis by focus-oriented chemotherapy of taeniasis.

The mortality, mortality, and disability due to Taenia solium neurocysticercosis are common and serious health problems in some regions, including several Asian countries. Neurocysticercosis in man and cysticercosis in pigs can be controlled by treatment, in man with a single, low (2 1/2 or 5 mg/kg) and safe dose of praziquantel. The problem which remains is the identification of a Taenia solium taeniasis foci. The definition of a focus is: T. solium-infected or suspected case; household with recent case of epilepsy in family or cysticercosis in pigs; group of houses or a village with high rate of cysticercosis in pigs. In a rural area a focus can be easily identified by tracing infected pigs to their place of origin, or in vivo tongue examination. All people with suspected T. solium taeniasis in a focus should be treated.

Laboratory rodent models for the tapeworm-stage of Taenia saginata and other related taeniid species.

Attempts were carried out to establish alternative definitive host systems for Taenia saginata, T. crassiceps, T. hydatigena, Echinococcus multilocularis and E. granulosus, in rodents. Following oral inoculation of cysticerci or protoscoleces, the tapeworm-stage development and sexual maturation of the 5 taeniid species in the intestine of a golden hamster (GH) and Mongolian gerbil (MG), both treated with prednisolone, were examined. Sexually mature T. saginata tapeworms were recovered from MG pretreated with prednisolone. The life cycles of E. multilocularis can be completed in MG and T. crassiceps in both MG and GH. T. hydatigena and E. granulosus developed to a certain extent at the tapeworm stage in MG pretreated with prednisolone. Potential use of rodents as an alternative definitive host for taeniid species is discussed.

Teníases / Taeniasis

O autor estuda os principais tópicos desta enfermedade parasitária e destaca sua moderna terapêutica com praziquantel

Teniasis-cisticercosis como problema de Salud Pública / Taeniasis-cysticercosis as a Public Health problem

Las cestodiasis de importancia sanitaria principal en México, son causadas por la T. solium y T. saginata. El cerdo es el huésped intermediario del Cysticercus cellolosae (fase larvaria de la T. sodium), aunque el hombre y el perro pueden ser infectados, con lesiones del tejido subcutáneo, músculo estriado, ojos y cerebro. La teniasis-cisticercosis humana se ha relacionado epidemiológicamente con los malos hábitos higiénicos, la insalubridad ambiental y en ausencia de un tratamiento adecuado, la infección por Taenia adulta suele persistir por varios años. La niclosamida, el albendazol y el praziquantel son medicamentos activos contra los céstodos adultos, siendo especialmente interesante la acción del praziquantel contra las fases larvarias de la T. saginata en los bovinos y el C. cellulosae en el hombre, con pocos efectos colaterales, siendo un producto no embriotóxico, ni teratogénico y sin efectos mutagénicos