RESUMO
The widespread dispersion of pigs infected with cysticercosis across endemic villages, low cyst burden among infected pigs, and low prevalence of taeniasis all suggest that pig ingestion of human feces is not the only mode of transmission for Taenia solium. Our objective was to evaluate the risk of porcine cysticercosis associated with exposure to human feces, dung beetles, and flies in an endemic community setting. We used a cluster-randomized cohort design to compare the risk of developing antibodies and infection among 120 piglets raised in either free-roaming (FR), standard corral (SC), or netted corral environments (NC). We collected monthly blood samples to detect serum antibodies and necropsied all pigs after 10 months to identify cysts. A total of 66 piglets developed antibodies with the relative risk of seropositivity in FR vs. all corralled pigs increasing significantly after 18 weeks. Of 108 necropsied pigs, 15 had T. solium cysts, all belonging to the FR group. Corrals were protective against infection but less so against seropositivity. NC, which did not completely exclude insects, did not provide added protection against seropositivity as compared to SC. The results of this study suggest that dung beetles and flies do not play an important role in infection.
RESUMO
Enzyme-linked immunoelectrotransfer blot (EITB) detects antibodies against seven Taenia solium larvae antigens in three protein families (GP50, T24/42, and 8-kDa) with different structures and functions. EITB banding patterns against these antigens in pigs provide information about the course of infection and may discriminate viable cysticercosis. We analyzed the banding patterns and infection outcomes (presence of viable cysts, degenerated cysts, and any cysts) of 512 rural pigs. Banding patterns were grouped into homogenous classes using latent class analysis, and relationships with infection outcomes were assessed. Four classes were identified: 1 (n = 308, EITB-negative or positive for the GP50 family), 2 (n = 127, positive for GP50 (GP50 family), GP42-39 and GP24 (T24/42 family), but negative for 8-kDa antigens), 3 (n = 22, positive for GP50 and T24/42 antigens (GP42-39 and GP24), as well as to 8-kDa bands GP13, GP14, and GP18, but negative for GP21), and 4 (n = 55, positive for GP50 and T24/42 antigens, as well as to 8-kDa antigens GP21 and GP18 in combination). Pigs in classes 3 and 4 were more likely to have viable cysts (72.6% and 96.4%, respectively) than pigs in classes 1 and 2 (0.7% and 27.6%, respectively; p < 0.001). The number of infections with any cysts was higher in classes 3 and 4 (77.3% and 98.2%, respectively) and lower in classes 2 and 1 (34.7% and 4.9%, respectively; p < 0.001). Pigs with viable cysts represented >90% of pigs with any cysts in classes 3 and 4 (94.1% and 98.2%, respectively), while degenerated cysts were frequent among pigs with any cysts in classes 1, 3, and 2 (86.7%, 47.1%, and 43.2%, respectively; p < 0.001). EITB banding patterns strongly correlate with cysticercosis infection status in rural pigs, with classes 3 and 4 being more predictive of viable infections.
RESUMO
Infection with the pork tapeworm (Taenia solium) is responsible for a substantial global burden of disease, not only restricted to its impact on human health, but also resulting in a considerable economic burden to smallholder pig farmers due to pig cysticercosis infection. The life-cycle, parasitology and immunology of T. solium are complex, involving pigs (the intermediate host, harbouring the larval metacestode stage), humans (the definitive host, harbouring the adult tapeworm, in addition to acting as accidental intermediate hosts) and the environment (the source of infection with eggs/proglottids). We review the parasitology, immunology, and epidemiology of the infection associated with each of the T. solium life-cycle stages, including the pre-adult/adult tapeworm responsible for human taeniasis; post-oncosphere and cysticercus associated with porcine and human cysticercosis, and the biological characteristics of eggs in the environment. We discuss the burden associated, in endemic settings, with neurocysticercosis (NCC) in humans, and the broader cross-sectoral economic impact associated both with NCC and porcine cysticercosis, the latter impacting food-value chains. Existing tools for diagnostics and control interventions that target different stages of the T. solium transmission cycle are reviewed and their limitations discussed. Currently, no national T. solium control programmes have been established in endemic areas, with further work required to identify optimal strategies according to epidemiological setting. There is increasing evidence suggesting that cross-sectoral interventions which target the parasite in both the human and pig host provide the most effective approaches for achieving control and ultimately elimination. We discuss future avenues for research on T. solium to support the attainment of the goals proposed in the revised World Health Organisation neglected tropical diseases roadmap for 2021-2030 adopted at the 73rd World Health Assembly in November 2020.
Assuntos
Taenia solium/fisiologia , Teníase/parasitologia , África/epidemiologia , Fatores Etários , Animais , Ásia/epidemiologia , América Central/epidemiologia , Cisticercose/diagnóstico , Cisticercose/epidemiologia , Cisticercose/parasitologia , Cisticercose/prevenção & controle , Humanos , Estágios do Ciclo de Vida , Prevalência , Fatores Sexuais , América do Sul/epidemiologia , Suínos , Doenças dos Suínos/diagnóstico , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/parasitologia , Doenças dos Suínos/prevenção & controle , Taenia solium/crescimento & desenvolvimento , Taenia solium/imunologia , Teníase/diagnóstico , Teníase/epidemiologia , Teníase/prevenção & controleRESUMO
The aim of this study was to assess transmission of Taenia solium cysticercosis in Palmarito Arriba, a small village in the rural area of the Portuguesa state of Venezuela, through (1) an evaluation of T. solium transmission risk factors present in the community and (2) serological detection of the secreted metacestode HP10 antigen (HP10 Ag) and of anti-metacestode antibodies in sera from rural pigs. Risk factors associated with transmission of cysticercosis were the following: 100% (23/23) of the households lacked piped water, 87.0% (20/23) of households lacked latrines, 88.0% (100/114) of inhabitants routinely defecated in the open/air, 19.05% (12/63) of the interviewed population had observed proglottids in their stools. More significantly, 9/13 householders breeding pigs reported seeing proglottids in their stools. Of the 25 pigs available for bleeding and serological testing, 64% (16/25) were free roaming and 36% (9/25) were "backyard" animals; 28% (7/25) were seropositive for both the HP10 Ag and antibody, 20.0% (5/25) were seropositive for HP10 Ag alone, and 36.0% (9/25) were seropositive for antibody alone. Given this clear evidence of endemic porcine cysticercosis, further studies are needed to assess and control the level of porcine and human taeniasis and cysticercosis in this and neighboring communities.
Assuntos
Cisticercose/veterinária , Doenças dos Suínos/epidemiologia , Taenia solium/fisiologia , Animais , Anticorpos Anti-Helmínticos/sangue , Antígenos de Helmintos/sangue , Cisticercose/epidemiologia , Cisticercose/parasitologia , Cisticercose/transmissão , Feminino , Masculino , Fatores de Risco , Estudos Soroepidemiológicos , Sus scrofa , Suínos , Doenças dos Suínos/parasitologia , Doenças dos Suínos/transmissão , Venezuela/epidemiologiaRESUMO
RESUMEN Objetivo: Evaluar la prevalencia de cisticercosis porcina en la parroquia rural Atahualpa, un poblado donde se ha demostrado endemia de neurocisticercosis humana. Diseño: Para el presente estudio, se colectarán muestras de sangre de aproximadamente 600 cerdos, las cuales serán procesadas mediante la prueba de EITB para estimar la tasa actual de sero-prevalencia de cisticercosis porcina. Unicamente se considerará el muestreo en cerdos a partir de los 2 meses de edad. Asimismo, solo se considerarán a aquellos animales sin evidencia de manifestaciones clínicas que hagan riesgosa su manipulación durante la toma de muestras de sangre. El presente estudio no contempla riesgo para la salud de los animales durante la toma de muestras. De acuerdo a las características de endemicidad de cisticercosis humana en Atahualpa, consideramos que la seroprevalencia esperada de cisticercosis porcina mediante EITB sea de al menos 25%. Entre los objetivos secundarios está el determinar los factores relacionados a una mayor o menor seroprevalencia de cisticercosis porcina (de la esperada). Todos los cerdos que resulten positivos (al menos 3 bandas) en el EITB, serán subsecuentemente tratados con oxfendazole, utilizando el régimen de dosis única de 30 mg/kg. Comentario: La importancia de definir la presencia de infección en la población porcina de una zona híper-endémica de neurocisticercosis humana radica en confirmar la existencia de transmisión activa. Si ésta es demostrada, el tratamiento de los cerdos infectados ayudará a interrumpir el ciclo de la Taenia solium y reducirá la prevalencia de esta enfermedad.
ABSTRACT Objective: To assess sero-prevalence of porcine cysticercosis in Atahualpa, a rural Ecuadorian village endemic for human neurocysticercosis. Design: We aim to collect at least 600 blood samples of local pigs, to quantify the number of positive bands in the EITB, and to estimate crude prevalence rates of porcine cysticercosis in the village. Sampling will only include pigs older than 2 months of age. Only healthy pigs will be sampled, to avoid risks inherent to manipulation of sick animals. There will be no risk for pigs as the result of the procedure. According to the estimated endemicity of human cysticercosis, we expect to find about 25% of infected pigs in this study. In the event of prevalence rates above or below the expected percentage, we will attempt to assess the causes of such discrepancies. All pig positive to 3 bands of more in the EITB will receive treatment with oxfendazole at a single dose of 30 mg/kg. Comment: The importance of defining the prevalence of porcine cysticercosis in a village endemic for human neurocysticercosis is to confirm the existence of active transmission. If this is true, treatment of infected pigs will help to interrupt the life cycle of Taenia solium, thus reducing the prevalence of this disease in humans.
RESUMO
The Enzyme-linked Immunoelectrotransfer Blot (EITB) has been used widely as a screening test for Taenia solium cysticercosis in swine. However, the relation between seropositivity and infection in pig populations from endemic areas has not been well defined. The aim of this study is to relate EITB seropositivity with infection and infection burden, analyse the trade-off between sensitivity and specificity with various cut-off points for the EITB assay, and finally describe the serology changes in a cohort of rural pigs raised under natural conditions. A group of 107 pigs that were used as controls during a vaccination field trial in Peru was our study population. The prevalence of porcine cysticercosis determined by necropsy examination was 16.82% (18/107) in these animals. Using EITB reactivity to ≥ 1 band as a cut-off point for the assay, the sensitivity was 88.89% (65.29-98.62, 95% CI) and the specificity was 48.31% (37.59-59.16, 95% CI). Comparing other cut-off points, involving up to as many as 7 reactive bands, a reactivity of ≥ 3 bands provided the best trade-offs in sensitivity and specificity. Using this cut-off point for the assay, the sensitivity was 77.77% (52.36-93.59, 95% CI) and the specificity was 76.40% (66.22-84.76, 95% CI). A significant association was found between cyst counts over 100 cysts and reactivity to ≥ 3 bands in the EITB assay (Fisher's exact test, p<0.05). The results of this study suggest that the use of the EITB assay to study porcine cysticercosis may require setting different cut-offs under field and experimental conditions, and depending upon the objective of the screening process.
Assuntos
Cisticercose/veterinária , Ensaio de Imunoadsorção Enzimática/veterinária , Doenças dos Suínos/diagnóstico , Animais , Cisticercose/diagnóstico , Cisticercose/epidemiologia , Cisticercose/parasitologia , Ensaio de Imunoadsorção Enzimática/normas , Carga Parasitária , Peru/epidemiologia , Reprodutibilidade dos Testes , População Rural , Sensibilidade e Especificidade , Estudos Soroepidemiológicos , Suínos , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/parasitologia , TempoRESUMO
A teníase é uma doença que se manifesta no ser humano em decorrência da presença da forma adulta da Taenia sp., enquanto a cisticercose decorre da infecção pelo estágio larvar da Taenia sp. ou Taenia solium, no caso dos suínos e humanos. Foi realizado um estudo transversal visando a determinar a prevalência de cisticercose em suínos e de teníase em 176 propriedades localizadas na zona rural de Viçosa, Minas Gerais (MG). Foram coletadas amostras de sangue de 226 suínos e fezes de 266 humanos, além da realização de um inquérito epidemiológico. Não foi identificada teníase humana, e a prevalência da cisticercose suína foi de 0,4 por cento. As informações obtidas mostraram que a maioria das pessoas possuía o hábito de consumir carne suína não inspecionada; entretanto, todas as pessoas se alimentavam da carne bem aquecida. Em apenas 1,1 por cento das propriedades, o esgoto era depositado diretamente no solo e em 99,4 por cento destas a água era canalizada, enquanto 88,1 por cento dos suínos eram criados presos. Concluiu-se que, na zona rural do município de Viçosa-MG, a prevalência do complexo teníase-cisticercose foi baixa, mostrando ainda um nível de contaminação inferior ao de outros municípios onde o complexo foi estudado.
Taeniasis occurs due to the presence of the adult form of Taenia sp. in human beings, and cysticercosis is caused by the presence of the larval stage of T. solium in pigs and humans. A transversal study was conducted aiming to determine the prevalence of porcine cysticercosis and Taeniasis in 176 farms located in rural areas of Viçosa-MG. Blood samples of 226 pigs, and feces samples of 266 humans were collected. An epidemiological survey has also been done. We found a prevalence of 0.4 percent of porcine cysticercosis and Taeniasis has not been found. The epidemiological data has shown that although most people consumed non-inspected pork, it used to be prepared well-done. Data showed that 88.1 percent of the pigs are reared in confinement in only 1.1 percent of the properties the sewer was disposed on the soil, and 99.4 percent used pipes for water distribution. It can be concluded that the prevalence of the Taeniasis-cysticercosis complex in rural areas of Viçosa (State of Minas Gerais) is lower than in other similar regions.
RESUMO
Taeniasis occurs due to the presence of the adult form of Taenia sp. in human beings, and cysticercosis is caused by the presence of the larval stage of T. solium in pigs and humans. A transversal study was conducted aiming to determine the prevalence of porcine cysticercosis and Taeniasis in 176 farms located in rural areas of Viçosa-MG. Blood samples of 226 pigs, and feces samples of 266 humans were collected. An epidemiological survey has also been done. We found a prevalence of 0.4% of porcine cysticercosis and Taeniasis has not been found. The epidemiological data has shown that although most people consumed non-inspected pork, it used to be prepared well-done. Data showed that 88.1% of the pigs are reared in confinement in only 1.1% of the properties the sewer was disposed on the soil, and 99.4% used pipes for water distribution. It can be concluded that the prevalence of the Taeniasis-cysticercosis complex in rural areas of Viçosa (State of Minas Gerais) is lower than in other similar regions.
A teníase é uma doença que se manifesta no ser humano em decorrência da presença da forma adulta da Taenia sp., enquanto a cisticercose decorre da infecção pelo estágio larvar da Taenia sp. ou Taenia solium, no caso dos suínos e humanos. Foi realizado um estudo transversal visando a determinar a prevalência de cisticercose em suínos e de teníase em 176 propriedades localizadas na zona rural de Viçosa, Minas Gerais (MG). Foram coletadas amostras de sangue de 226 suínos e fezes de 266 humanos, além da realização de um inquérito epidemiológico. Não foi identificada teníase humana, e a prevalência da cisticercose suína foi de 0,4%. As informações obtidas mostraram que a maioria das pessoas possuía o hábito de consumir carne suína não inspecionada; entretanto, todas as pessoas se alimentavam da carne bem aquecida. Em apenas 1,1% das propriedades, o esgoto era depositado diretamente no solo e em 99,4% destas a água era canalizada, enquanto 88,1% dos suínos eram criados presos. Concluiu-se que, na zona rural do município de Viçosa-MG, a prevalência do complexo teníase-cisticercose foi baixa, mostrando ainda um nível de contaminação inferior ao de outros municípios onde o complexo foi estudado.
RESUMO
Taeniasis occurs due to the presence of the adult form of Taenia sp. in human beings, and cysticercosis is caused by the presence of the larval stage of T. solium in pigs and humans. A transversal study was conducted aiming to determine the prevalence of porcine cysticercosis and Taeniasis in 176 farms located in rural areas of Viçosa-MG. Blood samples of 226 pigs, and feces samples of 266 humans were collected. An epidemiological survey has also been done. We found a prevalence of 0.4% of porcine cysticercosis and Taeniasis has not been found. The epidemiological data has shown that although most people consumed non-inspected pork, it used to be prepared well-done. Data showed that 88.1% of the pigs are reared in confinement in only 1.1% of the properties the sewer was disposed on the soil, and 99.4% used pipes for water distribution. It can be concluded that the prevalence of the Taeniasis-cysticercosis complex in rural areas of Viçosa (State of Minas Gerais) is lower than in other similar regions.
A teníase é uma doença que se manifesta no ser humano em decorrência da presença da forma adulta da Taenia sp., enquanto a cisticercose decorre da infecção pelo estágio larvar da Taenia sp. ou Taenia solium, no caso dos suínos e humanos. Foi realizado um estudo transversal visando a determinar a prevalência de cisticercose em suínos e de teníase em 176 propriedades localizadas na zona rural de Viçosa, Minas Gerais (MG). Foram coletadas amostras de sangue de 226 suínos e fezes de 266 humanos, além da realização de um inquérito epidemiológico. Não foi identificada teníase humana, e a prevalência da cisticercose suína foi de 0,4%. As informações obtidas mostraram que a maioria das pessoas possuía o hábito de consumir carne suína não inspecionada; entretanto, todas as pessoas se alimentavam da carne bem aquecida. Em apenas 1,1% das propriedades, o esgoto era depositado diretamente no solo e em 99,4% destas a água era canalizada, enquanto 88,1% dos suínos eram criados presos. Concluiu-se que, na zona rural do município de Viçosa-MG, a prevalência do complexo teníase-cisticercose foi baixa, mostrando ainda um nível de contaminação inferior ao de outros municípios onde o complexo foi estudado.
RESUMO
Taeniasis occurs due to the presence of the adult form of Taenia sp. in human beings, and cysticercosis is caused by the presence of the larval stage of T. solium in pigs and humans. A transversal study was conducted aiming to determine the prevalence of porcine cysticercosis and Taeniasis in 176 farms located in rural areas of Viçosa-MG. Blood samples of 226 pigs, and feces samples of 266 humans were collected. An epidemiological survey has also been done. We found a prevalence of 0.4% of porcine cysticercosis and Taeniasis has not been found. The epidemiological data has shown that although most people consumed non-inspected pork, it used to be prepared well-done. Data showed that 88.1% of the pigs are reared in confinement in only 1.1% of the properties the sewer was disposed on the soil, and 99.4% used pipes for water distribution. It can be concluded that the prevalence of the Taeniasis-cysticercosis complex in rural areas of Viçosa (State of Minas Gerais) is lower than in other similar regions.
A teníase é uma doença que se manifesta no ser humano em decorrência da presença da forma adulta da Taenia sp., enquanto a cisticercose decorre da infecção pelo estágio larvar da Taenia sp. ou Taenia solium, no caso dos suínos e humanos. Foi realizado um estudo transversal visando a determinar a prevalência de cisticercose em suínos e de teníase em 176 propriedades localizadas na zona rural de Viçosa, Minas Gerais (MG). Foram coletadas amostras de sangue de 226 suínos e fezes de 266 humanos, além da realização de um inquérito epidemiológico. Não foi identificada teníase humana, e a prevalência da cisticercose suína foi de 0,4%. As informações obtidas mostraram que a maioria das pessoas possuía o hábito de consumir carne suína não inspecionada; entretanto, todas as pessoas se alimentavam da carne bem aquecida. Em apenas 1,1% das propriedades, o esgoto era depositado diretamente no solo e em 99,4% destas a água era canalizada, enquanto 88,1% dos suínos eram criados presos. Concluiu-se que, na zona rural do município de Viçosa-MG, a prevalência do complexo teníase-cisticercose foi baixa, mostrando ainda um nível de contaminação inferior ao de outros municípios onde o complexo foi estudado.