RESUMO
Thousands of families live in agrarian reform rural settlements, these existing in Brazil since the 1980s. Factors such as agglomerations of families living in the same environment and the production of domestic animals can promote the transmission and maintenance of zoonosis in these areas. The epidemiology and geographic distribution of zoonotic diseases in settlement communities need to be highlighted. The present study aimed to investigate the prevalence, risk factors and spatial distribution of the teniasis-cysticercosis complex in the agrarian reform rural settlements in the state of Minas Gerais. A total of 497 family farming properties, distributed in 52 settlements, were randomly selected and sampled. Biological samples of humans, cattle and pigs were collected and processed. Survey questionnaires were applied in each family farming property to collect data on animal production as well as sanitary, hygienic and social conditions of each family. Human fecal samples were analyzed for detection of teniasis infection, while animal blood samples were collected and subjected to serological testing to detect the cysticercosis infection. A total of three (0.35%) positive cases of human teniasis were identified, 64 (4.2%) of bovine cysticercosis and 17 (3.3%) of swine cysticercosis. Prevalence per family farming unit was 0.6% (3/497) of taeniasis through fecal test, 5.8% (17/294) for swine cysticercosis and 11.1% (52/469) for bovine cysticercosis. The spatial profile for human teniasis and swine cysticercosis were clustered in two different regions, while bovine cysticercosis showed a dispersed geographical distribution. Two risk factors were associated with the occurrence of bovine cysticercosis: stream as source of water (p=0.009) and the environment as destination of sewage (p=0.031), while burning of garbage was shown to be a significant protective factor (p<0.001). Risk factor for swine cysticercosis was associated with the presence of free range pigs (p=0.008) and the environment as the destination of sewage (p≤0.024). The low number of positive human taeniasis did not allow statistical analysis. These zoonotic diseases represent a significant risk to public health because of their occurrence in livestock which are produced for both beef consumption and for commercialization. Significant endemic areas in the state of Minas Gerais have been determined in this study, and these discoverments suggest the importance of further investment in public health education about teniasis-cysticercosis transmission, the improvement of sanitary facilities for the settlements such as source and treatment of water and adequate destination of sewage. Integrated actions between the human, animal and environmental health sectors, at local and regional levels are needed, aiming at the adoption of effective public policies for the control and eradication of the teniasis-cysticercosis complex where the disease occurs.
Milhares de famílias vivem nos assentamentos da reforma agrária, criados no Brasil desde a década de 1980. Fatores como aglomerações de famílias convivendo no mesmo ambiente de produção de animais domésticos podem favorecer a transmissão e manutenção de zoonoses nessas áreas. A epidemiologia e distribuição geográfica das doenças zoonóticas nas comunidades assentadas precisam ser destacadas. Neste sentido, o presente estudo objetivou investigar a prevalência, fatores de risco e distribuição espacial do complexo teníase-cisticercose nos assentamentos rurais da reforma agrária no estado de Minas Gerais. Um total de 497 propriedades da agricultura familiar, distribuídas em 52 assentamentos, foram selecionadas e amostradas aleatoriamente. Amostras biológicas de humanos, bovinos e suínos foram coletadas e processadas. Questionários epidemiológicos foram aplicados em cada propriedade para a coleta de dados sobre a produção animal, condições sanitárias, higiênicas e sociais de cada família. Amostras fecais humanas foram analisadas para detecção de infecção por teníase, e amostras de sangue de animais foram coletadas e submetidas a testes sorológicos para detecção de infecção por cisticercose. Foram encontrados três (0,35%) casos positivos para teníase humana, 64 (4,2%) para cisticercose bovina e 17 (3,3%) para cisticercose suína. A prevalência por unidade de agricultura familiar foi de 0,6% (3/497) para teníase por exame fecal, 5,8% (17/294) para cisticercose suína e 11,1% (52/469) para cisticercose bovina. O perfil espacial da teníase humana e da cisticercose suína agrupou-se em duas regiões distintas, enquanto a cisticercose bovina apresentou distribuição geográfica dispersa. Dois fatores de risco estiveram associados à ocorrência de cisticercose bovina: riacho como fonte de água (p=0,009) e meio ambiente como destino de esgoto (p=0,031), enquanto a queima de lixo mostrou-se um fator de proteção significativo (p<0,001). O fator de risco para cisticercose suína foi associado à presença de suínos caipira (p=0,008) e ao meio ambiente como destino do esgoto (p≤0,024). Estas doenças zoonóticas representam um risco significativo para a saúde pública devido à sua ocorrência em rebanhos que são produzidos tanto para consumo de carne quanto para comercialização. Neste estudo os assentamentos analisados se configuram em áreas endêmicas no estado de Minas Gerais, e esses achados sugerem a importância de maiores investimentos na educação em saúde pública, melhoria das instalações sanitárias dos assentamentos como fonte e tratamento de água e destinação adequada de esgoto. São necessárias ações integradas entre os setores de saúde humana, animal e ambiental, em âmbito local e regional, visando a adoção de políticas públicas efetivas de controle e erradicação do complexo teníase-cisticercose onde estiver presente.
Assuntos
Teníase/transmissão , Teníase/epidemiologia , Cisticercose/transmissão , Cisticercose/epidemiologia , Saúde da População Rural , População Rural , Bovinos/parasitologia , Sus scrofa/parasitologiaRESUMO
BACKGROUND: The pork tapeworm, Taenia solium, is a serious public health problem in rural low-resource areas of Latin America, Africa and Asia, where the associated conditions of nuerocysticercosis (NCC) and porcine cysticercosis cause substantial health and economic harms. An accurate and validated transmission model for T. solium would serve as an important new tool for control and elimination, as it would allow for comparison of available intervention strategies, and prioritization of the most effective strategies for control and elimination efforts. METHODS: We developed a spatially-explicit agent-based model (ABM) for T. solium ("CystiAgent") that differs from prior T. solium models by including a spatial framework and behavioral parameters such as pig roaming, open human defecation, and human travel. In this article, we introduce the structure and function of the model, describe the data sources used to parameterize the model, and apply sensitivity analyses (Latin hypercube sampling-partial rank correlation coefficient (LHS-PRCC)) to evaluate model parameters. RESULTS: LHS-PRCC analysis of CystiAgent found that the parameters with the greatest impact on model uncertainty were the roaming range of pigs, the infectious duration of human taeniasis, use of latrines, and the set of "tuning" parameters defining the probabilities of infection in humans and pigs given exposure to T. solium. CONCLUSIONS: CystiAgent is a novel ABM that has the ability to model spatial and behavioral features of T. solium transmission not available in other models. There is a small set of impactful model parameters that contribute uncertainty to the model and may impact the accuracy of model projections. Field and laboratory studies to better understand these key components of transmission may help reduce uncertainty, while current applications of CystiAgent may consider calibration of these parameters to improve model performance. These results will ultimately allow for improved interpretation of model validation results, and usage of the model to compare available control and elimination strategies for T. solium.
Assuntos
Transmissão de Doença Infecciosa , Modelos Estatísticos , Teníase/transmissão , Animais , Cisticercose/transmissão , Cisticercose/veterinária , Humanos , Peru/epidemiologia , Saúde Pública , Fatores de Risco , Suínos/parasitologia , Doenças dos Suínos/transmissão , Taenia soliumRESUMO
The cystiSim model was used to compare strategies for the control of Taenia solium. A three-monthly intervention in pigs for 3 years was substantially more effective than biannual treatment for taeniasis in the human population for 5 years. The intervention period could be shortened further by combining pig and human interventions.
Assuntos
Modelos Teóricos , Neurocisticercose/prevenção & controle , Doenças dos Suínos/prevenção & controle , Teníase/prevenção & controle , Zoonoses/prevenção & controle , Animais , Humanos , Suínos , Doenças dos Suínos/tratamento farmacológico , Taenia solium/fisiologia , Teníase/transmissãoRESUMO
BACKGROUND: The application of effective vaccines against pig cysticercosis and mass chemotherapy against pig cysticercosis and human taeniasis have shown the feasibility of interrupting the parasite's life cycle in endemic areas. METHODS: A mathematical model that divides the population into susceptible, infected, and vaccinated individuals is formulated. The model is based upon the life cycle of the parasite. Computer numerical simulation experiments to evaluate the impact of pig vaccination under different vaccination schedules, and combined intervention strategies including pig vaccination and anthelmintic treatment against human taeniasis are carried out. RESULTS: Vaccination against either pig cysticercosis or against human taeniasis will influence the transmission dynamics not only among vaccinees but also the dynamics of the other hosts as well. When the protective efficacy and/or the coverage rate is less than 100%, different mass interventions like vaccinating the pig population twice in combination with chemotherapeutic treatment against human taeniasis, the elimination of the infection in both pigs and humans can also be achieved. CONCLUSIONS: Our mathematical model has the potential for planning, and designing effective intervention strategies including both mass vaccination and/or chemotherapeutic treatment to eliminate pig cysticercosis, human taeniasis and human neurocysticercosis. The model can be adapted to any given community with mild, moderate endemicity, or even in hyperendemic regions.
Assuntos
Cisticercose/prevenção & controle , Modelos Teóricos , Teníase/prevenção & controle , Vacinação/métodos , Vacinas/administração & dosagem , Animais , Cisticercose/transmissão , Tratamento Farmacológico/métodos , Humanos , Suínos , Teníase/transmissãoRESUMO
Reintroduction of Taenia solium into a region in Peru where it had been eliminated prompted evaluation of the possibility of reintroduction from an urban reservoir of taeniasis. In a cross-sectional study of an adjacent urban area, we found low prevalence of taeniasis (4/1,621; 0.25%), suggesting minimal risk of parasite reintroduction into rural areas through this route.
Assuntos
Neurocisticercose/epidemiologia , Teníase/epidemiologia , População Urbana , Adulto , Idoso , Animais , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Peru/epidemiologia , Prevalência , Fatores de Risco , Taenia solium/isolamento & purificação , Teníase/complicações , Teníase/transmissão , Adulto JovemRESUMO
BACKGROUND: Taenia solium is the aetiological agent of human taeniasis, pig cysticercosis and human neurocysticercosis, which are serious public health problems, especially in developing countries. METHODS: A mathematical model of the transmission dynamics of taeniasis-cysticercosis is formulated. The model consists of a coupled system of differential equations, which are density-dependent equations for describing the flow of the parasite through the life cycle. The model is hybrid since it comprises deterministic equations with stochastic elements which describe changes in the mean parasite burden and incorporates the overall pattern of the parasites' distribution. RESULTS: Sensitivity and bifurcation analyses were carried out to determine the range of values of the model. The model can reproduce the observed epidemiological patterns of human taeniasis, pig and human cysticercosis. For example, for a wide range of parameter values, the mean intensity of adult worms tends to rapidly stabilize in one parasite per individual host. From this model, we also derived a Susceptible-Infected model to describe the prevalence of infection in humans and pigs. Chemotherapeutic interventions against pig cysticercosis or human taeniasis may reduce rapidly and effectively the mean intensity of human taeniasis, pig cysticercosis and human cysticercosis. This effect can be achieved even if the protective efficacy of the drug is of the order of 90% and the coverage rate is 90%. This means that health in humans infected either with adult worms or cysticerci may be achieved by the application of anthelmintic drugs against pig cysticercosis. However, treatment against human cysticercosis alone, does not influence neither human teniasis nor pig cysticercosis. This is because human cysticercosis infection does not influence the value of the basic reproductive number (Ro). CONCLUSIONS: Even coverage of 100% in the administration of anthelmintics did not eliminate the infection. Then elimination of the infection in all hosts does not seem a feasible goal to achieve by administering only chemotherapeutic interventions. Throughout the manuscript a discussion of our model in the context of other models of taeniasis-cysticercosis is presented.
Assuntos
Anti-Helmínticos/uso terapêutico , Cisticercose/tratamento farmacológico , Cisticercose/transmissão , Modelos Teóricos , Taenia solium/efeitos dos fármacos , Animais , Anti-Helmínticos/farmacologia , Cisticercose/fisiopatologia , Humanos , Estágios do Ciclo de Vida/efeitos dos fármacos , Estágios do Ciclo de Vida/fisiologia , Suínos , Taenia solium/isolamento & purificação , Taenia solium/fisiologia , Teníase/tratamento farmacológico , Teníase/fisiopatologia , Teníase/transmissãoRESUMO
The aim of this study was to demonstrate the presence of Taenia solium eggs in beetles collected from sources within the natural environment through molecular techniques. Fifty-four pools of beetles were collected in three villages in Piura, Peru. DNA was extracted using the FastDNA spin kit for soil. Molecular identification of Taenia species was then performed through partial amplification of the mitochondrial cytochrome C oxidase subunit I gene. Finally, positive samples were sequenced to determine the tapeworm species. Seven positive samples were obtained through polymerase chain reaction amplification. Sequencing confirmed that two samples were from T. solium and three samples were from Taenia hydatigena. The other two samples could not be specifically identified. Our findings demonstrate that dung beetles ingest T. solium and T. hydatigena eggs under natural conditions and suggest that beetles may play a role in the dynamics of transmission of these cestodes.
Assuntos
Besouros/parasitologia , DNA de Helmintos/genética , Óvulo , Taenia solium/isolamento & purificação , Teníase/transmissão , Animais , DNA de Helmintos/isolamento & purificação , Contagem de Ovos de Parasitas , Peru/epidemiologia , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Taenia/genética , Taenia/isolamento & purificação , Taenia solium/genética , Teníase/epidemiologia , Teníase/parasitologiaRESUMO
The existence of cryptic species in the genus Hydatigera, cyclophillid cestodes, mainly of felids, was recently described based on molecular studies of parasites from Asia, Europe and Africa. However, the occurrence of H. taeniaeformis sensu stricto (s.s.), the species more widely distributed and with a presumed specificity for murid rodents as intermediate hosts, has not been formally described in Americas. In the present study, during necropsy of an Ingram's squirrel specimen, Guerlinguetus ingrami, found dead in the municipality of Belo Horizonte, Minas Gerais state, Brazil, strobilocerci were found in the liver. The metacestodes were subjected to morphological and molecular studies. Sequences of the COI barcode region were obtained and used for phylogenetic analyses. The morphology and measures of the rostellar hooks were compatible with the ones described for H. taeniaeformis s.s. This identification was confirmed by a molecular phylogenetic approach (96.2-99.7% similarity with isolates of the parasite from Europe and Asia). This is the first molecular confirmation of the existence of H. taeniaeformis s.s. on the American continent. Moreover, the involvement of sciurid rodents in the transmission of H. taeniaeformis s.s. is discussed here as a probable case of parasite spillover.
Assuntos
Cestoides/genética , Sciuridae/parasitologia , Taenia/genética , América/epidemiologia , Animais , Brasil/epidemiologia , Cestoides/isolamento & purificação , Código de Barras de DNA Taxonômico/métodos , Fígado/parasitologia , Taenia/isolamento & purificação , Teníase/epidemiologia , Teníase/parasitologia , Teníase/transmissãoRESUMO
The adult Taenia solium, the pork tapeworm, usually lives as a single worm in the small intestine of humans, its only known definitive host. Mechanisms of genetic variation in T. solium are poorly understood. Using three microsatellite markers previously reported [1], this study explored the genetic variability of T. solium from cysts recovered from experimentally infected pigs. It then explored the genetic epidemiology and transmission in naturally infected pigs and adult tapeworms recovered from human carriers from an endemic rural community in Peru. In an initial study on experimental infection, two groups of three piglets were each infected with proglottids from one of two genetically different tapeworms for each of the microsatellites. After 7 weeks, pigs were slaughtered and necropsy performed. Thirty-six (92.3%) out of 39 cysts originated from one tapeworm, and 27 (100%) out of 27 cysts from the other had exactly the same genotype as the parental tapeworm. This suggests that the microsatellite markers may be a useful tool for studying the transmission of T. solium. In the second study, we analyzed the genetic variation of T. solium in cysts recovered from eight naturally infected pigs, and from adult tapeworms recovered from four human carriers; they showed genetic variability. Four pigs had cysts with only one genotype, and four pigs had cysts with two different genotypes, suggesting that multiple infections of genetically distinct parental tapeworms are possible. Six pigs harbored cysts with a genotype corresponding to one of the identified tapeworms from the human carriers. In the dendrogram, cysts appeared to cluster within the corresponding pigs as well as with the geographical origin, but this association was not statistically significant. We conclude that genotyping of microsatellite size polymorphisms is a potentially important tool to trace the spread of infection and pinpoint sources of infection as pigs spread cysts with a shared parental genotype.
Assuntos
Cisticercose/veterinária , Repetições de Microssatélites/genética , Taenia solium/genética , Teníase/veterinária , Animais , Cisticercose/parasitologia , Cisticercose/transmissão , Cysticercus/genética , Cysticercus/isolamento & purificação , Cistos/parasitologia , Modelos Animais de Doenças , Feminino , Variação Genética/genética , Genótipo , Masculino , Peru , Sus scrofa , Suínos , Doenças dos Suínos/parasitologia , Taenia solium/isolamento & purificação , Teníase/parasitologia , Teníase/transmissãoRESUMO
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.).
Assuntos
Cisticercose/transmissão , Transmissão de Doença Infecciosa/prevenção & controle , Doenças Endêmicas/prevenção & controle , Taenia solium , Adolescente , Adulto , Animais , Anti-Helmínticos/uso terapêutico , Cisticercose/prevenção & controle , Cisticercose/veterinária , Estudos de Viabilidade , Feminino , Educação em Saúde , Humanos , Masculino , Programas de Rastreamento , Pessoa de Meia-Idade , Peru , Sus scrofa/parasitologia , Taenia solium/isolamento & purificação , Teníase/prevenção & controle , Teníase/transmissão , Vacinas , Adulto JovemRESUMO
BACKGROUND: Taenia solium is a major cause of preventable epilepsy in developing nations. Screening and treatment of human intestinal stage infection (taeniasis) within high-risk foci may reduce transmission and prevent epilepsy by limiting human exposure to infective eggs. We piloted a ring-strategy that involves screening and treatment for taeniasis among households located nearby pigs heavily-infected with the larval stage (cysticercosis). These pigs mark areas of increased transmission and can be identified by tongue examination. METHODOLOGY: We selected two villages in northern Peru for a controlled prospective interventional cohort pilot study. In the intervention village (1,058 residents) we examined the tongues of all pigs every 4 months for nodules characteristic of cysticercosis. We then screened all residents living within 100-meters of any tongue-positive pig using enzyme-linked immunosorbent assay to detect Taenia antigens in stool. Residents with taeniasis were treated with niclosamide. In both the intervention and control (753 residents) we measured incidence of exposure by sampling the pig population every 4 months for serum antibodies against cysticercosis using enzyme-linked immunoelectrotransfer blot. PRINCIPAL FINDINGS: Baseline seroincidence among pigs born during the study was 22.6 cases per 100 pigs per-month (95% confidence interval [CI] 17.0-30.0) in the intervention and 18.1 (95% CI 12.7-25.9) in the control. After one year we observed a 41% reduction in seroincidence in the intervention village compared to baseline (incidence rate ratio 0.59, 95% CI 0.41-0.87) while the seroincidence in the control village remained unchanged. At study end, the prevalence of taeniasis was nearly 4 times lower in the intervention than in the control (prevalence ratio 0.28, 95% CI 0.08-0.91). CONCLUSIONS/SIGNIFICANCE: Ring-screening reduced transmission of T. solium in this pilot study and may provide an effective and practical approach for regions where resources are limited. However, this strategy requires validation in larger populations over a greater period of time.
Assuntos
Anticorpos Anti-Helmínticos/sangue , Doenças dos Suínos/parasitologia , Taenia solium , Teníase/veterinária , Língua/parasitologia , Animais , Anticestoides/uso terapêutico , Pré-Escolar , Cisticercose/epidemiologia , Fezes , Feminino , Humanos , Incidência , Masculino , Niclosamida/uso terapêutico , Peru/epidemiologia , Projetos Piloto , Prevalência , Estudos Prospectivos , Suínos , Doenças dos Suínos/epidemiologia , Teníase/epidemiologia , Teníase/transmissão , ZoonosesRESUMO
The life cycle of Taenia solium, the pork tapeworm, is continuously closed in many rural settings in developing countries when free roaming pigs ingest human stools containing T. solium eggs and develop cysticercosis, and humans ingest pork infected with cystic larvae and develop intestinal taeniasis, or may also accidentally acquire cysticercosis by faecal-oral contamination. Cysticercosis of the human nervous system, neurocysticercosis, is a major cause of seizures and other neurological morbidity in most of the world. The dynamics of exposure, infection and disease as well as the location of parasites result in a complex interaction which involves immune evasion mechanisms and involutive or progressive disease along time. Moreover, existing data are limited by the relative lack of animal models. This manuscript revises the available information on the immunology of human taeniasis and cysticercosis.
Assuntos
Carne/parasitologia , Doenças dos Suínos/parasitologia , Taenia solium/imunologia , Teníase/veterinária , Animais , Cisticercose/imunologia , Cisticercose/transmissão , Interações Hospedeiro-Parasita/imunologia , Humanos , Estágios do Ciclo de Vida , Suínos , Doenças dos Suínos/imunologia , Taenia solium/crescimento & desenvolvimento , Teníase/imunologia , Teníase/patologia , Teníase/transmissãoRESUMO
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.
Assuntos
Animais , Feminino , Masculino , Animais Selvagens/parasitologia , Capillaria/isolamento & purificação , Reservatórios de Doenças , Infecções por Enoplida/veterinária , Hepatite Animal/epidemiologia , Fígado/parasitologia , Ratos/parasitologia , Doenças dos Roedores/epidemiologia , Taenia/isolamento & purificação , Teníase/veterinária , Capillaria/crescimento & desenvolvimento , Colômbia/epidemiologia , Cistos/parasitologia , Cistos/veterinária , Infecções por Enoplida/epidemiologia , Infecções por Enoplida/parasitologia , Infecções por Enoplida/transmissão , Granuloma/parasitologia , Granuloma/veterinária , Hepatite Animal/parasitologia , Larva , Óvulo , Doenças dos Roedores/parasitologia , Taenia/crescimento & desenvolvimento , Teníase/epidemiologia , Teníase/parasitologia , Teníase/transmissão , Saúde da População Urbana , ZoonosesRESUMO
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.
Assuntos
Animais Selvagens/parasitologia , Capillaria/isolamento & purificação , Reservatórios de Doenças , Infecções por Enoplida/veterinária , Hepatite Animal/epidemiologia , Fígado/parasitologia , Ratos/parasitologia , Doenças dos Roedores/epidemiologia , Taenia/isolamento & purificação , Teníase/veterinária , Animais , Capillaria/crescimento & desenvolvimento , Colômbia/epidemiologia , Cistos/parasitologia , Cistos/veterinária , Infecções por Enoplida/epidemiologia , Infecções por Enoplida/parasitologia , Infecções por Enoplida/transmissão , Feminino , Granuloma/parasitologia , Granuloma/veterinária , Hepatite Animal/parasitologia , Larva , Masculino , Óvulo , Doenças dos Roedores/parasitologia , Taenia/crescimento & desenvolvimento , Teníase/epidemiologia , Teníase/parasitologia , Teníase/transmissão , Saúde da População Urbana , ZoonosesRESUMO
Cysticercosis is due to the establishment of the larval stage of the zoonotic cestode parasite Taenia solium. The infection causes substantial human morbidity and mortality, particularly in several Latin American countries and parts of Africa and Asia, as well as economic losses in pig husban dry due to condemnation of infected pork meat. The life cycle of T. solium includes human beings as definitive hosts and pigs as intermediate hosts. Cysticercosis is acquired by the ingestion of eggs released by human tapeworm carriers, who become infected after ingesting pork meat contaminated with cysticerci. Taenia solium transmission has been associated with poverty, lack of sanitary services and practices of rearing backyard pigs with free access to the areas that villagers use as toilets, as well as cultural behaviour. Nonetheless, due to the recent increase of migration and tourism, industrial countries are also reporting cases of human cysticercosis. There are many epidemiological studies that have been conducted mainly in Latin American countries that have evaluated intervention measures for control of cysticercosis including the development and testing of vaccines. Furthermore, the involvement of international agencies and institutions, such as the World Health Organization, the Food and Agriculture Organization and the International Livestock Research Institute, as well as the commitment of policymakers, scientists and field workers, are key means for the sustainable control and, hopefully, eradication of T. solium infections.
Assuntos
Criação de Animais Domésticos/métodos , Cisticercose/veterinária , Doenças dos Suínos/prevenção & controle , Teníase/veterinária , Animais , Cisticercose/prevenção & controle , Cisticercose/transmissão , Parasitologia de Alimentos , Saúde Global , Humanos , Cooperação Internacional , Prevalência , Suínos , Doenças dos Suínos/transmissão , Taenia solium/crescimento & desenvolvimento , Taenia solium/imunologia , Teníase/prevenção & controle , Teníase/transmissão , Vacinação/veterinária , ZoonosesRESUMO
The tapeworms of the genus Taenia that infect human beings are T. solium, T. saginata and T. saginata asiatica. Taenia solium and T. saginata exhibit unequivocal features that characterize them; in contrast, only recent DNA studies, morphological characteristics, and epidemiological and sanitary aspects indicate that T. saginata asiatica is a subspecies of T. saginata. These 3 tapeworms occur in humans in their adult stage, and the intermediate hosts are pigs for T. solium and T. saginata asiatica and cows for T. saginata. Their identification is crucial considering the migratory increase from Asia to the Western Hemisphere and the fact that these tapeworms coexist in the same environment in Asia; furthermore, it is estimated that movement in both directions across the United States-Mexico border exceeds 200 million persons per yr, and thus, opportunities for acquiring and transporting T. solium infections are multiplied. It is not easy to distinguish among these tapeworms; therefore, a comparative diagram of the 3 parasites is shown in this article, which will facilitate their identification. All morphological features, some of which allow for identification, are clear and can be easily distinguished among the 3 tapeworms.
Assuntos
Taenia saginata/anatomia & histologia , Taenia solium/anatomia & histologia , Teníase/parasitologia , Animais , Encéfalo/parasitologia , Bovinos , Coração/parasitologia , Humanos , Fígado/parasitologia , Suínos , Taenia saginata/classificação , Taenia saginata/isolamento & purificação , Taenia solium/classificação , Taenia solium/isolamento & purificação , Teníase/transmissãoRESUMO
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).
Assuntos
Anticorpos Anti-Helmínticos/sangue , Doenças dos Suínos/epidemiologia , Taenia solium/imunologia , Teníase/veterinária , Fatores Etários , Animais , Feminino , Incidência , Masculino , Peru/epidemiologia , Estudos Soroepidemiológicos , Fatores Sexuais , Suínos , Doenças dos Suínos/parasitologia , Doenças dos Suínos/transmissão , Taenia solium/patogenicidade , Teníase/epidemiologia , Teníase/transmissãoRESUMO
Studies were carried out on the recovery rate and cysticerci location in bovines experimentally infected with Taenia saginata eggs. Three calves of 6.5 months and one with 19 months of age were infected orally with 2 x 10(4) eggs of Taenia saginata. A fifth calf served as control. After 90 days of infection, the animals were slaughtered and organs and skeletal muscles were inspected using a slicing technique every 5 mm. From the four infected calves, 702 cysticerci were recovered, of which 570 (81.2 percent) were alive and 132 (18.8 percent) were degenerated. The recovery rate ranged from 0.01 to 1.43 percent with an average of 0.88 percent. The cysticerci presented the following anatomical distribution: hioideos muscles 02 (0.28 percent), kidneys 03 (0.43 percent), tongue 07 (1.00 percent), liver 12 (1.71 percent), lungs 15 (2.14 percent), diaphragm 18 (2.56 percent), mastication muscles 25 (3.56 percent), heart 49 (6.98 percent), anterior muscle 323 (46.00 percent) and posterior muscle 248 (35.33 percent)