RESUMO
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: Hydatidosis is a zoonotic disease of worldwide distribution caused by Echinococcus granulosus. Our study aimed to determine the prevalence of human and canine echinococcosis as well as the associated risk factors in a rural area of the Limarí province in northern Chile. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional study was conducted between August and November 2009 using a stratified sampling design in each of the five districts of the province. In the selected villages, up to 10 households were sampled. Serum and fecal samples from an adult family member and a dog were collected from each participating household. Risk factors were assessed by standardized questionnaires. Seroprevalence was assessed using a multi-step approach: an ELISA for screening, IFA, IHA and western blot for confirmation of results, respectively. The prevalence of echinococcal infection in dogs was determined by coproantigen genus specific ELISA. Chi-square, Fisher tests and logistic regressions were used to assess risk factors for human seropositivity and dog copropositivity. A seroprevalence of 2.6% (10/403) and coproprevalence of 28% (26/93) was recorded for humans and dogs respectively. Contact with dogs and dog feces were risk factors for human seropositivity while dog copropositivity was associated with home slaughter of livestock (ORâ=â3.35; CI 90%: 1.16-6.85) and households de-worming dogs (ORâ=â2.82; CI 90%: 1.33-8.43). CONCLUSIONS/SIGNIFICANCE: Echinococcal infection of humans and their dogs is common in Limarí province. Risk factors for human seropositivity were related to contact with domestic dogs and their feces, whereas those for dogs were home slaughter of livestock and the practice of de-worming dogs.
Assuntos
Equinococose , Adolescente , Adulto , Animais , Chile/epidemiologia , Estudos Transversais , Cães , Equinococose/epidemiologia , Equinococose/veterinária , Feminino , Humanos , Masculino , Prevalência , Fatores de Risco , População Rural , Inquéritos e Questionários , Adulto JovemRESUMO
Echinococcus granulosus infections are a major public health problem in livestock-raising regions around the world. The life cycle of this tapeworm is sustained between dogs (definitive host, canine echinococcosis), and herbivores (intermediary host, cystic hydatid disease). Humans may also develop cystic hydatid disease. Echinococcosis is endemic in rural areas of Peru; nevertheless, its presence or the extension of the problem in urban areas is basically unknown. Migration into Lima, an 8-million habitant's metropolis, creates peripheral areas where animals brought from endemic areas are slaughtered without veterinary supervision. We identified eight informal, unlicensed abattoirs in a peripheral district of Lima and performed a cross-sectional study in to assess the prevalence of canine echinococcosis, evaluated by coproELISA followed by PCR evaluation and arecoline purge. Eight of 22 dogs (36%) were positive to coproELISA, and four (18%) were confirmed to be infected with E. granulosus tapeworms either by PCR or direct observation (purge). Later evaluation of the human population living in these abattoirs using abdominal ultrasound, chest X-rays and serology, found 3 out of 32 (9.3%) subjects with echinococcal cysts in the liver (two viable, one calcified), one of whom had also lung involvement and a strongly positive antibody response. Autochthonous transmission of E. granulosus is present in Lima. Informal, unlicensed abattoirs may be sources of infection to neighbouring people in this urban environment.
Assuntos
Matadouros , Doenças do Cão/epidemiologia , Equinococose/epidemiologia , Equinococose/veterinária , Echinococcus granulosus/isolamento & purificação , Adolescente , Adulto , Idoso , Animais , Criança , Pré-Escolar , Estudos Transversais , Doenças do Cão/parasitologia , Cães , Equinococose/diagnóstico , Equinococose/parasitologia , Ensaio de Imunoadsorção Enzimática , Fezes/parasitologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Peru/epidemiologia , Reação em Cadeia da Polimerase , Prevalência , População Urbana , Adulto JovemRESUMO
Taenia solium causes taeniasis and cysticercosis, a zoonotic complex associated with a significant burden of epilepsy in most countries. Reliable diagnosis and efficacious treatment of taeniasis are needed for disease control. Currently, cure can be confirmed only after a period of at least 1 month, by negative stool microscopy. This study assessed the performance of detection by a coproantigen enzyme-linked immunosorbent assay (CoAg-ELISA) for the early evaluation of the efficacy of antiparasitic treatment of human T. solium taeniasis. We followed 69 tapeworm carriers who received niclosamide as standard treatment. Stool samples were collected on days 1, 3, 7, 15, 30, and 90 after treatment and were processed by microscopy and CoAg-ELISA. The efficacy of niclosamide was 77.9% (53/68). Thirteen patients received a second course of treatment and completed the follow-up. CoAg-ELISA was therefore evaluated for a total of 81 cases (68 treatments, 13 retreatments). In successful treatments (n = 64), the proportion of patients who became negative by CoAg-ELISA was 62.5% after 3 days, 89.1% after 7 days, 96.9% after 15 days, and 100% after 30 days. In treatment failures (n = 17), the CoAg-ELISA result was positive for 70.6% of patients after 3 days, 94.1% after 7 days, and 100% after 15 and 30 days. Only 2 of 17 samples in cases of treatment failure became positive by microscopy by day 30. The presence of one scolex, but not multiple scolices, in posttreatment stools was strongly associated with cure (odds ratio [OR], 52.5; P < 0.001). CoAg-ELISA is useful for the assessment of treatment failure in taeniasis. Early assessment at day 15 would detect treatment failure before patients become infective.
Assuntos
Antígenos de Helmintos/análise , Técnicas de Laboratório Clínico/métodos , Fezes/química , Parasitologia/métodos , Taenia solium/imunologia , Teníase/diagnóstico , Teníase/parasitologia , Adolescente , Adulto , Animais , Anti-Helmínticos/administração & dosagem , Monitoramento de Medicamentos/métodos , Diagnóstico Precoce , Ensaio de Imunoadsorção Enzimática/métodos , Fezes/parasitologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Niclosamida/administração & dosagem , Estudos Prospectivos , Teníase/tratamento farmacológico , Fatores de Tempo , Falha de Tratamento , Adulto JovemRESUMO
Cyst echinococcosis (CE) is one of the most important zoonosis in Chile, where studies have focussed mainly in moist southern regions. The present study was conducted to determine the prevalence of cystic echinococcosis (CE) in livestock and humans in the semiarid Coquimbo region in north-central Chile. A review of all surgical cases of CE in humans reported in the Elqui, Limarí and Choapa provinces in Coquimbo region for the period comprising 1995-2006 was obtained. In addition, a retrospective study of CE covering condemnation records from slaughterhouses of these provinces from the same period was carried out. The surgical incidence of CE in humans ranged between 2.3 and 8.5 cases per 10(5) people, with more cases reported in provinces with a higher percentage of rural inhabitants (Limarí and Choapa). A total of 174,034 cattle, 22,208 goats, 35,404 sheep, 25,355 swine and 9391 equines were examined during the period. Higher prevalence of CE was detected in cattle (24%), followed by swine (14%), sheep (11%), goats (6%), and equines (9%). More cases of CE in livestock were also found in provinces with higher rural population. The overall trend of the prevalence of CE for each livestock species across years was a significant downward one, except for swine in Elqui and sheep and swine in Choapa. Cattle showed higher prevalence of CE in liver in Elqui, in kidney in Limarí and in lungs in Choapa. Swine showed similar prevalence by organs in all provinces. Sheep showed higher prevalence of CE in liver in Elqui and Limarí and lower prevalence in Choapa. Goats presented higher prevalence of CE in kidney in all provinces, and equines had higher prevalence of CE in liver in the provinces where animals were slaughtered. Further studied are needed to assess whether these differences are due to different strains affecting these species or due to ecological factors. When analyzing the CE prevalence of each species within each province, a negative correlation between prevalence of CE in goats and rainfall in the Limarí province was found. This could be attributed to changes in management practices and/or ecological factors. This study shows that surveillance of CE at slaughterhouses combined with the analyses of incidence in humans can be used to detect areas with a higher risk of infection. Improvements in record-keeping of infected animals at slaughterhouses are proposed in order to trace back farms where infection was most likely acquired.
Assuntos
Equinococose/epidemiologia , Equinococose/patologia , Echinococcus granulosus/fisiologia , Animais , Bovinos , Chile/epidemiologia , Equinococose/cirurgia , Cabras , Cavalos , Humanos , Prevalência , Estudos Retrospectivos , Ovinos , SuínosRESUMO
Hydatidosis is a zoonotic disease caused by the cystic stage of the cestode parasite Echinoccocus granulosus, in which the definitive hosts are mainly domestic dogs. This parasite is regarded mainly as a rural disease, where man is exposed through contact with eggs excreted by definitive hosts; however, some studies have shown that domestic dogs can get infected within urban areas. This study was conducted to assess differences in prevalence of E. granulosus in urban and rural sites in Coquimbo region of Chile. From 2005 to 2006 a cross-sectional household questionnaire survey was conducted in Coquimbo and Ovalle cities, in three towns and in rural sites along two transects from these cities to the Fray Jorge NP in the Coquimbo region. Faecal samples were collected from dogs during the questionnaire survey and tested for Echinococcus coproantigens. Positive dogs were found in urban areas. Analysis of risk factors indicated that dogs inhabiting the borders of urban areas were at greater risk of being coproantigen positive than those in the centre of these areas. These results are likely to be related to the custom of slaughtering livestock at home in urban areas during local celebrations, which could favour the importation of E. granulosus to urban areas by acquiring livestock contaminated with cysts from rural sites. This study shows that surveillance and control measures in livestock and domestic dogs need to be introduced in urban areas as well as rural areas of the Coquimbo region to reduce the public health risk of hydatid disease.
Assuntos
Doenças do Cão/epidemiologia , Equinococose/veterinária , Echinococcus granulosus/fisiologia , População Rural , População Urbana , Animais , Chile , Estudos Transversais , Doenças do Cão/diagnóstico , Cães , Equinococose/diagnóstico , Equinococose/epidemiologia , Fezes/parasitologia , Feminino , Modelos Logísticos , Masculino , Prevalência , Fatores de RiscoRESUMO
Taenia solium causes human neurocysticercosis and is endemic in underdeveloped countries where backyard pig keeping is common. Microscopic fecal diagnostic methods for human T. solium taeniasis are not very sensitive, and Taenia saginata and Taenia solium eggs are indistinguishable under the light microscope. Coproantigen (CoAg) ELISA methods are very sensitive, but currently only genus (Taenia) specific. This paper describes the development of a highly species-specific coproantigen ELISA test to detect T. solium intestinal taeniasis. Sensitivity was maintained using a capture antibody of rabbit IgG against T. solium adult whole worm somatic extract, whereas species specificity was achieved by utilization of an enzyme-conjugated rabbit IgG against T. solium adult excretory-secretory (ES) antigen. A known panel of positive and negative human fecal samples was tested with this hybrid sandwich ELISA. The ELISA test gave 100% specificity and 96.4% sensitivity for T. solium tapeworm carriers (N = 28), with a J index of 0.96. This simple ELISA incorporating anti-adult somatic and anti-adult ES antibodies provides the first potentially species-specific coproantigen test for human T. solium taeniasis.