RESUMEN
Background: Taeniasis and cysticercosis are major causes of seizures and epilepsy. Infection by the causative parasite Taenia solium requires transmission between humans and pigs. The disease is considered to be eradicable, but data on attempts at regional elimination are lacking. We conducted a three-phase control program in Tumbes, Peru, to determine whether regional elimination would be feasible. Methods: We systematically tested and compared elimination strategies to show the feasibility of interrupting the transmission of T. solium infection in a region of highly endemic disease in Peru. In phase 1, we assessed the effectiveness and feasibility of six intervention strategies that involved screening of humans and pigs, antiparasitic treatment, prevention education, and pig replacement in 42 villages. In phase 2, we compared mass treatment with mass screening (each either with or without vaccination of pigs) in 17 villages. In phase 3, we implemented the final strategy of mass treatment of humans along with the mass treatment and vaccination of pigs in the entire rural region of Tumbes (107 villages comprising 81,170 people and 55,638 pigs). The effect of the intervention was measured after phases 2 and 3 with the use of detailed necropsy to detect pigs with live, nondegenerated cysts capable of causing new infection. The necropsy sampling was weighted in that we preferentially included more samples from seropositive pigs than from seronegative pigs. Results: Only two of the strategies implemented in phase 1 resulted in limited control over the transmission of T. solium infection, which highlighted the need to intensify the subsequent strategies. After the strategies in phase 2 were implemented, no cyst that was capable of further transmission of T. solium infection was found among 658 sampled pigs. One year later, without further intervention, 7 of 310 sampled pigs had live, nondegenerated cysts, but no infected pig was found in 11 of 17 villages, including all the villages in which mass antiparasitic treatment plus vaccination was implemented. After the final strategy was implemented in phase 3, a total of 3 of 342 pigs had live, nondegenerated cysts, but no infected pig was found in 105 of 107 villages. Conclusions: We showed that the transmission of T. solium infection was interrupted on a regional scale in a highly endemic region in Peru. (Funded by the Bill and Melinda Gates Foundation and others).
Introducción: La teniasis y la cisticercosis son causas importantes de convulsiones y epilepsia. La infección por el parásito causal Taenia solium requiere la transmisión entre humanos y cerdos. La enfermedad se considera erradicable, pero faltan datos sobre los intentos de eliminación regional. Llevamos a cabo un programa de control de tres fases en Tumbes, Perú, para determinar si sería factible la eliminación regional. Métodos: Probamos y comparamos sistemáticamente las estrategias de eliminación para demostrar la viabilidad de interrumpir la transmisión de la infección por T. solium en una región de enfermedad altamente endémica en Perú. En la fase 1, evaluamos la eficacia y viabilidad de seis estrategias de intervención que incluyeron detección de humanos y cerdos, tratamiento antiparasitario, educación preventiva y reemplazo de cerdos en 42 aldeas. En la fase 2, comparamos el tratamiento masivo con la detección masiva (cada una con o sin vacunación de cerdos) en 17 aldeas. En la fase 3, implementamos la estrategia final de tratamiento masivo de humanos junto con el tratamiento masivo y vacunación de cerdos en toda la región rural de Tumbes (107 aldeas que comprenden 81.170 personas y 55.638 cerdos). El efecto de la intervención se midió después de las fases 2 y 3 con el uso de necropsia detallada para detectar cerdos con quistes vivos, no degenerados capaces de causar una nueva infección. El muestreo de necropsia fue ponderado de manera que incluimos preferentemente más muestras de cerdos seropositivos que de cerdos seronegativos. Resultados: Sólo dos de las estrategias implementadas en la fase 1 dieron como resultado un control limitado sobre la transmisión de la infección por T. solium, lo que destacó la necesidad de intensificar las estrategias posteriores. Después de que se implementaron las estrategias en la fase 2, no se encontró ningún quiste capaz de transmitir más la infección por T. solium entre los 658 cerdos muestreados. Un año después, sin más intervenciones, 7 de los 310 cerdos muestreados tenían quistes vivos, no degenerados, pero no se encontró ningún cerdo infectado en 11 de las 17 aldeas, incluidas todas las aldeas en las que se implementó el tratamiento antiparasitario masivo más la vacunación. Después de que se implementó la estrategia final en la fase 3, un total de 3 de 342 cerdos tenían quistes vivos, no degenerados, pero no se encontró ningún cerdo infectado en 105 de las 107 aldeas. Conclusiones: Demostramos que la transmisión de la infección por T. solium se interrumpió a escala regional en una región altamente endémica del Perú. (Financiado por la Fundación Bill y Melinda Gates y otros).
Asunto(s)
CisticercosisRESUMEN
A single enhancing lesion in the brain parenchyma, also called an inflammatory granuloma, is a frequent neurologic diagnosis. One of the commonest causes of this lesion is human neurocysticercosis, the infection by the larvae of the pork tapeworm, Taenia solium. Following the demonstration that viable cysticercosis cysts survive in good conditions for several years in the human brain, single cysticercal granulomas have been consistently interpreted as representing late degeneration of a long-established parasite. On the basis of epidemiologic, clinical, and laboratory evidence detailed in this article, we hypothesize that in most cases these inflammatory lesions correspond to parasites that die in the early steps of infection, likely as the natural result of the host immunity overcoming mild infections.
Asunto(s)
Granuloma/etiología , Neurocisticercosis/complicaciones , Animales , Encéfalo/microbiología , Encéfalo/patología , Granuloma/epidemiología , Granuloma/inmunología , Humanos , Imagen por Resonancia Magnética/métodos , Neurocisticercosis/epidemiología , Neurocisticercosis/inmunología , Taenia solium/patogenicidad , Tomografía Computarizada por Rayos X/métodosRESUMEN
A combined (human and porcine) mass chemotherapy program was tested in a controlled design in 12 village hamlets in the Peruvian highlands. A single dose of 5 mg of praziquantel was given to eliminate intestinal taeniasis in humans, and two rounds of oxfendazole (30 mg/kg) were administered to all pigs. The total population in the study villages was 5,658 resident individuals, and the porcine population at the beginning of the study was 716 pigs. Human treatment coverage was 75%, ranging from 69% to 80%. There were only a few refusals of owners for porcine treatment of their animals. The effect of the intervention was measured by comparing incidence rates (seroconversion in pigs who were seronegative 4 months before) in treatment versus control villages, before and up to 18 months after treatment. There was a clear effect in decreasing prevalence (odds ratio, 0.51; P < 0.001) and incidence (odds ratio, 0.39; P < 0.013) in the treatment area after the intervention, which did not leave to extinction of the parasite but stabilized in slightly decreased rates persisting along the follow-up period. Mass chemotherapy was effective in decreasing infection pressure in this hyperendemic area. However, the magnitude of the effect was small and did not attain the goal of eliminating transmission.
Asunto(s)
Anticestodos/administración & dosificación , Bencimidazoles/administración & dosificación , Praziquantel/administración & dosificación , Teniasis/epidemiología , Teniasis/prevención & control , Adolescente , Adulto , Animales , Niño , Femenino , Humanos , Incidencia , Masculino , Perú/epidemiología , Estudios Seroepidemiológicos , Porcinos , Enfermedades de los Porcinos/sangre , Enfermedades de los Porcinos/tratamiento farmacológico , Enfermedades de los Porcinos/epidemiología , Enfermedades de los Porcinos/prevención & control , Taenia solium , Teniasis/sangre , Teniasis/tratamiento farmacológicoRESUMEN
BACKGROUND: Neurocysticercosis (NCC) is the commonest helminthic CNS infection and the main cause of adult-onset seizures in developing countries, also frequent in industrialized countries because of immigration from endemic zones. Although NCC is commonly seen in individuals with seizures in endemic areas, its role as a cause of epilepsy has been questioned on the basis of the poor methodology of published studies. OBJECTIVE: To determine, in a cysticercosis-endemic area of the northern Peruvian coast, the frequency of 1) epileptic seizures, 2) serum antibodies to Taenia solium, 3) NCC-compatible findings on brain CT, and 4) the associations between these variables. METHODS: A community-wide screening survey for possible seizure cases was performed using a validated questionnaire. Positive respondents were later examined in the field by neurologists. Seizure cases were categorized as single seizure, active epilepsy, or inactive epilepsy. Serology was performed for all consenting individuals using immunoblot. Noncontrast brain CT scans were performed in all individuals with seizures and two groups of control subjects without seizures (seropositive and seronegative). RESULTS: The screening survey was applied to 903 permanent residents. Most positive respondents (114/137 [83.2%]) were examined by neurologists. The overall prevalence of epilepsy was 32.1 per 1,000 and that of active epilepsy was 16.6 per 1,000. Seroprevalence was 24.2% (200/825). Seroprevalence was associated with seizures (odds ratio 2.14; p = 0.026). Brain CT abnormalities compatible with NCC were more frequent in individuals with seizures and in those seropositive. CONCLUSION: In this hyperendemic area, an important proportion of seizure cases are associated with neurocysticercosis as demonstrated by serology or brain CT.
Asunto(s)
Encéfalo/parasitología , Epilepsia/epidemiología , Epilepsia/parasitología , Neurocisticercosis/diagnóstico por imagen , Neurocisticercosis/epidemiología , Adolescente , Adulto , Anticuerpos/sangre , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Causalidad , Niño , Preescolar , Comorbilidad , Estudios Transversales , Epilepsia/sangre , Femenino , Encuestas Epidemiológicas , Humanos , Lactante , Recién Nacido , Masculino , Tamizaje Masivo , Persona de Mediana Edad , Neurocisticercosis/patología , Perú/epidemiología , Estudios Seroepidemiológicos , Encuestas y Cuestionarios , Taenia solium/inmunología , Tomografía Computarizada por Rayos XRESUMEN
We performed repeated serological sampling of pigs in an endemic area of the Peruvian highlands (eight villages) to assess the feasibility of detecting incident cases of Taenia solium infection as indicators of ongoing transmission of the parasite. A total of 2245 samples corresponding to 1548 pigs were collected in three sampling rounds (n=716, 926, and 603, respectively). Village-period specific seroprevalences of antibodies by enzyme-linked immunoelectrotransfer blot (EITB) assay varied from 39% (95% CI: 34, 44) to 76% (95% CI: 72, 79). The prevalence of cysticercosis increased with the age of the pigs (similarly for both sexes). Around 40% of pigs were re-sampled at the end of each 4-month period. Crude incidence risks were 48% (57/120, 95% CI: 43-52) and 58% (111/192, 95% CI: 54-61) for each period. A proportion of seropositive animals became seronegative at the end of each period (23 and 15%). Incidence varied by the village, and the exposure period, and was higher in males than females (but did not differ by age).
Asunto(s)
Anticuerpos Antihelmínticos/sangre , Enfermedades de los Porcinos/epidemiología , Taenia solium/inmunología , Teniasis/veterinaria , Factores de Edad , Animales , Femenino , Incidencia , Masculino , Perú/epidemiología , Estudios Seroepidemiológicos , Factores Sexuales , Porcinos , Enfermedades de los Porcinos/parasitología , Enfermedades de los Porcinos/transmisión , Taenia solium/patogenicidad , Teniasis/epidemiología , Teniasis/transmisiónRESUMEN
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.
Asunto(s)
Cisticercosis/epidemiología , Epilepsia/epidemiología , Toxocariasis/epidemiología , Adulto , Edad de Inicio , Animales , Bolivia/epidemiología , Estudios de Casos y Controles , Cisticercosis/diagnóstico , Cisticercosis/parasitología , Dieta , Electroencefalografía , Ensayo de Inmunoadsorción Enzimática , Epilepsias Parciales/epidemiología , Epilepsias Parciales/etiología , Epilepsias Parciales/parasitología , Epilepsia/diagnóstico , Epilepsia/parasitología , Epilepsia Generalizada/epidemiología , Epilepsia Generalizada/etiología , Epilepsia Generalizada/parasitología , Femenino , Humanos , Inmunoelectroforesis , Masculino , Tamizaje Masivo , Población Rural , Saneamiento , Toxocara , Toxocara canis , Toxocariasis/diagnóstico , Toxocariasis/parasitologíaRESUMEN
We examined the genetic variability in the pig-human tapeworm, Taenia solium, by sequencing the genes for cytochrome oxidase I, internal transcribed spacer 1, and a diagnostic antigen, Ts14, from individual cysts isolated from Peru, Colombia, Mexico, India, China, and the Philippines. For these genes, the rate of nucleotide variation was minimal. Isolates from these countries can be distinguished based on one to eight nucleotide differences in the 396 nucleotide cytochrome oxidase I (COI) sequence. However, all of the 15 isolates from within Peru had identical COI sequences. The Ts14 sequences from India and China were identical and differed from the Peru sequence by three nucleotides in 333. These data indicate that there is minimal genetic variability within the species T. solium. Minimal variability was also seen in the ITS1 sequence, but this variation was observed within the individual. Twenty-two cloned sequences from six isolates sorted into 13 unique sequences. The variability observed within the sequences from individual cysts was as great as the variability between the isolates.
Asunto(s)
Antígenos Helmínticos/genética , ADN de Helmintos/genética , ADN Espaciador Ribosómico/genética , Complejo IV de Transporte de Electrones/genética , Enfermedades de los Porcinos/parasitología , Taenia/genética , Teniasis/veterinaria , Animales , Secuencia de Bases , China , Colombia , ADN de Helmintos/aislamiento & purificación , Variación Genética , Humanos , India , México , Datos de Secuencia Molecular , Perú , Filipinas , Filogenia , Homología de Secuencia de Ácido Nucleico , Porcinos , Taenia/clasificación , Teniasis/parasitologíaRESUMEN
Neurocysticercosis is the most common helminthic infection of the CNS but its diagnosis remains difficult. Clinical manifestations are nonspecific, most neuroimaging findings are not pathognomonic, and some serologic tests have low sensitivity and specificity. The authors provide diagnostic criteria for neurocysticercosis based on objective clinical, imaging, immunologic, and epidemiologic data. These include four categories of criteria stratified on the basis of their diagnostic strength, including the following: 1) absolute--histologic demonstration of the parasite from biopsy of a brain or spinal cord lesion, cystic lesions showing the scolex on CT or MRI, and direct visualization of subretinal parasites by funduscopic examination; 2) major--lesions highly suggestive of neurocysticercosis on neuroimaging studies, positive serum enzyme-linked immunoelectrotransfer blot for the detection of anticysticercal antibodies, resolution of intracranial cystic lesions after therapy with albendazole or praziquantel, and spontaneous resolution of small single enhancing lesions; 3) minor--lesions compatible with neurocysticercosis on neuroimaging studies, clinical manifestations suggestive of neurocysticercosis, positive CSF enzyme-linked immunosorbent assay for detection of anticysticercal antibodies or cysticercal antigens, and cysticercosis outside the CNS; and 4) epidemiologic--evidence of a household contact with Taenia solium infection, individuals coming from or living in an area where cysticercosis is endemic, and history of frequent travel to disease-endemic areas. Interpretation of these criteria permits two degrees of diagnostic certainty: 1) definitive diagnosis, in patients who have one absolute criterion or in those who have two major plus one minor and one epidemiologic criterion; and 2) probable diagnosis, in patients who have one major plus two minor criteria, in those who have one major plus one minor and one epidemiologic criterion, and in those who have three minor plus one epidemiologic criterion.
Asunto(s)
Neurocisticercosis/diagnóstico , HumanosRESUMEN
Cysticercosis, the infection by the larvae of Taenia solium, is a major cause of acquired epilepsy in the world; it also causes significant economic loss because of contaminated pork. This disease is endemic in most developing countries and no control strategy has yet been proven efficient and sustainable. To further evaluate the full potential of single-dose oxfendazole treatment for pigs as a control measure, 20 pigs with cysticercosis were treated with oxfendazole and later matched with 41 naive pigs and exposed to a natural challenge in a hyperendemic area. New infections were found by serologic testing in 15 of the 32 controls (47%), and by the presence of cysts at necropsy in 12 of them (37%). Only minute residual scars were detected in the carcasses of oxfendazole-treated pigs. Pigs with cysticercosis, once treated with oxfendazole, are protected from new infections for at least three months.
Asunto(s)
Antihelmínticos/uso terapéutico , Bencimidazoles/uso terapéutico , Cisticercosis/veterinaria , Enfermedades de los Porcinos/prevención & control , Taenia/efectos de los fármacos , Animales , Anticuerpos Antihelmínticos/sangre , Encéfalo/parasitología , Cisticercosis/epidemiología , Cisticercosis/prevención & control , Immunoblotting/veterinaria , Estudios Prospectivos , Estudios Seroepidemiológicos , Porcinos , Enfermedades de los Porcinos/tratamiento farmacológico , Enfermedades de los Porcinos/parasitologíaRESUMEN
The discordance between extremely high seroprevalence of Taenia solium antibodies in disease-endemic populations, relatively few symptomatic cases of neurocysticercosis, and high background levels of putatively inactive brain lesions (mainly calcifications) in seronegative controls have confused researchers, clinicians, and epidemiologists in the last decade. We reviewed longitudinal serologic data from general population serosurveys in 3 different disease-endemic areas of Peru and Colombia and found that approximately 40% of seropositive people were seronegative when resampled after 1 year (3 surveys) or after 3 years (1 survey). Transient antibodies may have significant implications for the epidemiology of and immunity to this disease.
Asunto(s)
Anticuerpos Antihelmínticos/sangre , Cisticercosis/epidemiología , Cisticercosis/inmunología , Taenia/inmunología , Animales , Anticuerpos Antihelmínticos/biosíntesis , Antígenos Helmínticos/sangre , Colombia/epidemiología , Humanos , Immunoblotting , Estudios Longitudinales , Perú/epidemiología , Estudios SeroepidemiológicosRESUMEN
The efficacy of albendazole (ABZ) treatment for human neurocysticercosis (NCC) was assessed by using a monoclonal antibody-based parasite antigen detection ELISA which specifically detects the products of living cysticerci in human serum. The assay displayed 85% diagnostic sensitivity, detecting 39 of 46 NCC cases. Only patients with a single viable cyst or only enhancing lesions (degenerating parasites) were seronegative. Specificity of the assay was 92% (23/25) when tested in healthy Peruvian volunteers. In 'cured' patients, in whom all parasites died after ABZ therapy, parasite antigen levels fell sharply by 3 months post treatment. This pattern was not observed in patients refractory to treatment. The sensitivity of the assay with serum samples, and its ability to identify successfully treated patients, make this monoclonal antibody-based ELISA the test of choice for the follow-up of NCC cases.
Asunto(s)
Antígenos Helmínticos/sangre , Neurocisticercosis/diagnóstico , Adolescente , Adulto , Anciano , Albendazol/uso terapéutico , Antihelmínticos/uso terapéutico , Estudios de Cohortes , Ensayo de Inmunoadsorción Enzimática/normas , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Neurocisticercosis/tratamiento farmacológico , Neurocisticercosis/epidemiología , Perú/epidemiología , Sensibilidad y EspecificidadRESUMEN
Cysticercosis contributes to higher epilepsy rates in developing countries than in industrialized ones, yet no estimate exists for the associated burden of disease. We used epidemiological data on neurocysticercosis in Peru to calculate the burden of disease and applied our model to the other countries of Latin America where neurocysticercosis is endemic to determine a regional estimate. Analysis of 12 population-based community studies demonstrated that neurocysticercosis was endemic in highland areas and high jungles, with seroprevalences from 6% to 24%. In one community, the adult seizure disorder rate was 9.1% among seropositive persons versus 4. 6% among seronegative persons; we used this difference for estimates. On the basis of average prevalence rates in areas of endemicity of 6%-10%, we estimated that there are 23,512-39,186 symptomatic neurocysticercosis cases in Peru. In Latin America, an estimated 75 million persons live in areas where cysticercosis is endemic, and approximately 400,000 have symptomatic disease. Cysticercosis contributes substantially to neurological disease in Peru and in all of Latin America.
Asunto(s)
Neurocisticercosis/epidemiología , Animales , Países en Desarrollo , Humanos , Neurocisticercosis/prevención & control , Neurocisticercosis/transmisión , Perú/epidemiología , Estudios Seroepidemiológicos , PorcinosRESUMEN
We evaluated the presence and persistence of anticysticercal antibodies in piglets born to Taenia solium infected sows. Infected sows from a disease-endemic area of Peru were transported to a nondisease-endemic area and impregnated. Serum samples were collected from sows and piglets on Day 2 through Week 35 after birth. Using an immunoblot specific for cysticercosis, Ig isotypes to 7 cyst antigens were measured and quantified. Serum samples from the piglets contained detectable antibodies from Week 1 through Week 35 (27 weeks after weaning). The primary Ig isotype present in both sows and piglets was IgG. Antibodies did not appear in piglet serum samples until after suckling, demonstrating that anti-cysticercal antibodies are transferred solely via colostrum. Our data have shown that maternally transferred antibodies to cyst antigens may persist through much of a pig's life. Therefore, the presence of passively transferred antibodies must be considered in studies that examine the prevalence of cysticercosis in pigs. Furthermore, when designing control strategies for cysticercosis, careful evaluation and selection of sentinel pigs becomes a crucial component of sentinel selection.
Asunto(s)
Anticuerpos Antihelmínticos/sangre , Cisticercosis/veterinaria , Cysticercus/inmunología , Inmunidad Materno-Adquirida/inmunología , Enfermedades de los Porcinos/inmunología , Animales , Animales Recién Nacidos , Anticuerpos Monoclonales , Western Blotting/veterinaria , Cisticercosis/inmunología , Densitometría/veterinaria , Electroforesis en Gel de Poliacrilamida/veterinaria , Femenino , Masculino , Perú , Porcinos , Enfermedades de los Porcinos/parasitologíaRESUMEN
BACKGROUND: Taenia solium neurocysticercosis (NCC) has been documented as one of the major causes of epilepsy in developing countries. However, methodological limitations have hindered the evaluation of the epidemiological relationship between cysticercosis and epilepsy at the community level. METHODS: We used the WHO protocol for epidemiological evaluation of neurological disorders to conduct a door-to-door survey among 2723 residents of San Pablo del Lago, an Ecuadorean rural community in which T. solium taeniasis/cysticercosis was known to be endemic. The WHO protocol was complemented by neuroimaging and immunological tests to confirm the diagnosis of this infection. RESULTS: In all 31 people suffering from active epilepsy were detected (prevalence 11.4 per 1000, 95% CI:7.7-15.4); 26 agreed to undergo a computer tomography (CT) examination, and 28 agreed to have blood drawn for serodiagnosis. Fourteen of the 26 (53.8%) had CT changes compatible with NCC and six of the 28 (21.4%) tested positive in the enzyme-linked immunoelectro-transfer blot (EITB) assay. In a seizure-free random sample of this population, 17 of 118 (144 per 1000) subjects examined by CT and 10 out of 96 (104 per 1000) examined by EITB had evidence of this infection. The differences between the epilepsy group and the random sample of the population were statistically significant (OR = 6.93, 95% CI: 2.7-17.5, P < 0.001) for CT diagnosis, but not for EITB results (OR = 2.75, 95% CI: 0.8-7.1, P > 0.12, NS). CONCLUSIONS: These findings confirm that T. solium NCC is a significant cause of epilepsy at the community level in Andean villages of Ecuador. It is important to initiate effective public health interventions to eliminate this infection, which may be responsible for at least half of the cases of reported epilepsy in Ecuador.
Asunto(s)
Epilepsia/epidemiología , Neurocisticercosis/epidemiología , Adolescente , Adulto , Animales , Anticuerpos Antihelmínticos/análisis , Niño , Preescolar , Cysticercus/inmunología , Cysticercus/aislamiento & purificación , Ecuador/epidemiología , Ensayo de Inmunoadsorción Enzimática , Epilepsia/diagnóstico por imagen , Epilepsia/etiología , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Neurocisticercosis/complicaciones , Neurocisticercosis/diagnóstico por imagen , Vigilancia de la Población , Prevalencia , Población Rural , Tomografía Computarizada por Rayos XRESUMEN
A serological survey was performed using the enzyme-linked immunoelectrotransfer blot assay (EITB) in a village in the highlands of Peru where there are three distinct but close neighborhoods, to determine if there is a direct relationship between human and porcine Taenia solium infection. One hundred and eight out of 365 individuals were sampled, and 14 were seropositive (human seroprevalence 13%). Most seropositive individuals were neurologically asymptomatic. Thirty-eight out of 89 sampled pigs (43%) were seropositive. There was a clear geographical clustering of cases, and positive correlation between human and porcine seroprevalence found when comparing the three neighborhoods. Cysticercosis is an important cause of neurological morbidity in most developing countries, and control/eradication trials are now being increasingly applied. Porcine serology provides an appropriate indicator of T. solium environmental contamination and should be used to estimate the risk of infection when evaluating control measures.
Asunto(s)
Cisticercosis/epidemiología , Cisticercosis/veterinaria , Enfermedades de los Porcinos/epidemiología , Adulto , Anciano , Animales , Anticuerpos Antihelmínticos/sangre , Cisticercosis/parasitología , Femenino , Humanos , Técnicas para Inmunoenzimas , Masculino , Persona de Mediana Edad , Perú , Población Rural , Porcinos , Taenia/inmunología , ZoonosisRESUMEN
Taenia solium neurocysticercosis (NCC) has been documented to be an underlying cause of epilepsy, intractable headaches, hydrocephalus, dementia and other serious neurological conditions in many countries of Central and South America. However, methodological limitations had prevented the assessment of the true prevalence of this condition at the community level. We conducted a house-to-house neuroepidemiological survey of 6,118 residents of an Andean community. This information was used to target neuroimaging (CT-scan) and immunodiagnosis (enzyme-linked immunoelectrotransfer blot assay, EITB) tests in individuals suspected of harbouring Taenia solium NCC. In the rural population, NCC was confirmed in 8 out of 47 examined by CT-scan (17%) and in 6 of 42 examined by EITB (14%). In the urban population, NCC was confirmed in 35 of 147 examined by CT-scan (23.8%) and in 28 of 124 examined by EITB (22.6%). In a sample of relatives of patients with documented cerebral cysticercosis, 20 out of 81 examined by CT-scan (25%) and 12 of 79 (15%) examined by EITB had NCC. Finally, CT scans were performed for 83 school children from urban areas, and 9 (11%) were diagnosed as harbouring NCC. In a community-based study, cysticercosis appears to be much more frequent than initially thought, when CT examination is used as the "gold standard" for diagnosis.
Asunto(s)
Neurocisticercosis/epidemiología , Adolescente , Animales , Niño , Ecuador/epidemiología , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Immunoblotting , Masculino , Neurocisticercosis/diagnóstico , Taenia , Tomografía Computarizada por Rayos X , Población UrbanaRESUMEN
In our previous work, we reported the first systematic, island-wide, serologic survey for schistosomiasis in Puerto Rico in 40 years. In that study, approximately 3,000 serum samples from the 76 municipalities comprising the island of Puerto Rico were tested for the detection of antibodies to S. mansoni microsomal antigens by the Falcon assay screening test-enzyme-linked immunosorbent assay (FAST-ELISA) and those positive were confirmed by an enzyme-linked immunoelectrotransfer blot (EITB). The highest EITB positivity was found in 17 municipalities, which comprised 48% of all seropositive samples. An additional finding was that 10% of the 215 EITB-positive samples were from individuals 25 years or younger and were for the most part of residents from the high seroprevalence areas. Thus, for this study we focused on 766 individuals 25 years of age or younger (45.5% males and 54.4% females), two-thirds of which were from 10 municipalities with the highest EITB seropositivity, and one-third from the 10 municipalities with the lowest EITB seropositivity found in our previous study. Of all samples, the results showed an overall FAST-ELISA positivity of 11.6%, with males similar to females (12.6 versus 10.7%, respectively). Confirmation by EITB was only 1.8%, with a males three-fold higher than females (3% versus 0.7%). When seropositivity was measured by age in five-year increments, a clear age-specific decrease in seropositivity was observed. Thus, by FAST-ELISA, 16.7% of the 21-25-year-old age group was positive, decreasing to 14.6%, 9.9%, 7.9%, and 9.3% in the 16-20-, 11-15-, 6-10-, and 1-5-year-old age groups, respectively. Confirmatory EITB showed even more impressive results: 4.7%, 2.6%, 1.2%, 0.7%, and 0% in the same age brackets. With regard to the high prevalence municipalities, only four of 10 (11 of 228 = 4.8%) had confirmatory EITB-positive samples and most were from municipalities of the Rio Grande de Loiza River basin and tributaries. The male to female positivity ratio was 4:1. Of the low prevalence municipalities, only single positive cases (by EITB) were found in three disperse municipalities. These results support the concept that there has been little transmission of S. mansoni in Puerto Rico during the first half of the 1990s and confirms anecdotal comments of local physicians who have seen virtually no new infections during the past three years. This makes the documentation of eradication of schistosomiasis from Puerto Rico feasible, a goal that should be set as being before the 100th anniversary of its discovery on the island by Isaac Gonzalez-Martinez in 1904.
Asunto(s)
Esquistosomiasis/epidemiología , Adolescente , Adulto , Factores de Edad , Niño , Preescolar , Estudios de Cohortes , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Immunoblotting , Lactante , Masculino , Puerto Rico/epidemiología , Estudios SeroepidemiológicosRESUMEN
Human Taenia solium cysticercosis is a major cause of epilepsy in developing countries, and porcine infection causes widespread economic losses because of infested pork. Recently, the use of oxfendazole (OFZ) for porcine cysticercosis provided, for the first time, an effective, single-dose treatment. We performed a controlled study to determine the time required between treatment with a single dose of OFZ and the death of cysticerci to define its applicability as preslaughter treatment or as a field control measure. Twenty naturally infected pigs were included in this study. Sixteen received a single dose (30 mg/kg) of OFZ, and were killed in groups of four at one, two, four, and 12 weeks after treatment. Four untreated controls were killed at week 12. No adverse reactions to OFZ were noted. A clear decrease in viability and number of cysts was evident after the first week after therapy, but even at week 4 some viable cysticerci were found in all samples. Twelve weeks after treatment, all meat appeared clear and only minuscule scars remained, except in one animal that had viable brain cysts. This study confirms the efficacy of a single dose of 30 mg/kg of OFZ for porcine cysticercosis but demonstrates that preslaughter treatment of pigs with OFZ will not be useful in controlling cysticercosis. The inclusion of porcine treatment with OFZ in mass cysticercosis control programs is, however, highly promising because it is a simple, effective, inexpensive, and potentially sustainable method for decreasing the porcine reservoir of cysticercosis in disease-endemic countries.
Asunto(s)
Anticestodos/administración & dosificación , Bencimidazoles/administración & dosificación , Cisticercosis/veterinaria , Enfermedades de los Porcinos/tratamiento farmacológico , Animales , Cisticercosis/tratamiento farmacológico , Cisticercosis/parasitología , Cysticercus/efectos de los fármacos , Cysticercus/aislamiento & purificación , Reservorios de Enfermedades/veterinaria , Parasitología de Alimentos , Humanos , Carne/parasitología , Perú , Porcinos , Enfermedades de los Porcinos/parasitología , Factores de TiempoRESUMEN
An enzyme-linked immunosorbent assay (ELISA) for the detection of antigen secreted by viable Taenia solium metacestodes (Ag-ELISA) was applied to 43 pre-treatment and 47 follow-up cerebrospinal fluid (CSF) samples from Peruvian patients with neurocysticercosis demonstrated by computed tomography and enzyme-linked immunoelectrotransfer blot assay. The sensitivity of the assay was 86%. Negative pre-treatment results in the Ag-ELISA test were restricted to patients with only a single live cyst or only enhancing lesions. Patients with hydrocephalus had higher levels of circulating antigen. There was no difference between antigen levels in CSF taken before and immediately after treatment (day 14). Levels of parasite antigen were significantly positively correlated with the number of live cysts detected by tomography and were also proportional to the number and intensity of antibody reactions recognized by the immunoblot diagnostic test. In contrast, there was a negative correlation with the number of enhancing lesions revealed by tomography, supporting the hypothesis that enhancing lesions correspond to a terminal, moribund stage of the parasite. The use of antigen-detection tests specific for viable metacestodes has immediate utility in the clinical context, not only providing important information on the viability of the parasites but also leading to an improved understanding of the pathogenesis of neurocysticercosis before and after drug treatment.
Asunto(s)
Antígenos Helmínticos/aislamiento & purificación , Ensayo de Inmunoadsorción Enzimática/métodos , Neurocisticercosis/diagnóstico , Taenia/aislamiento & purificación , Adulto , Albendazol/uso terapéutico , Animales , Antihelmínticos/uso terapéutico , Femenino , Humanos , Hidrocefalia/parasitología , Masculino , Persona de Mediana Edad , Neurocisticercosis/líquido cefalorraquídeo , Neurocisticercosis/tratamiento farmacológico , Perú/epidemiología , Tomografía Computarizada por Rayos X/métodosRESUMEN
PURPOSE: A prospective series of 643 persons with epilepsy attending a reference neurologic center in Medellín, Colombia, was examined by computed tomography (CT scan) or serology or both with the enzyme-linked immunoelectrotransfer blot assay (EITB) to assess the prevalence of Taenia solium cysticercosis. METHODS: All presenting patients were consecutively enrolled in the study. Five hundred forty-six persons underwent cerebral CT scans; 376 of them also had serum EITB performed. RESULTS: Prevalence of neurocysticercosis by CT scan was 13.92%. Overall prevalence of T. solium antibodies with EITB was 9.82%, but for those with late-onset epilepsy (onset after age 30 years), prevalence increased to 17.5% and 19% for those who originated from outside urban Medellín. Seroprevalence in individuals with mixed lesions (cysts and calcifications) was 88.2% and 64.10% in those with live cysts. Conversely, only 2.72% of persons with CT findings not related to neurocysticercosis had positive EITB tests. CONCLUSIONS: Our study shows that an important proportion of individuals with epilepsy have radiologic or serologic evidence of T. solium infection, suggesting that neurocysticercosis is an important etiology for epilepsy in Colombia.