RESUMO
This collection of articles provides an account of the papers delivered at the 19th International Conference of the World Association for the Advancement of Veterinary Parasitology (WAAVP)(held in New Orleans, LA, USA, from 10 to 14 August 2003) in a symposium session on assessing the burden of Taenia solium cysticercosis and echinococcosis organised and chaired by A. Lee Willingham III from the WHO/FAO Collaborating Center for Research and Training on Emerging and other Parasitic Zoonoses in Denmark and Peter M. Schantz from the Parasitic Diseases Division of the US Centers for Disease Control and Prevention, USA. The focus was on the persistence of the zoonotic parasitic diseases cysticercosis, caused by the pork tapeworm T. solium, and echinococcosis,caused by species of the tapeworm Echinococcus, and why these diseases are given very little attention on the national and international agendas in spite of the availability of tools to detect, treat,control and prevent them when it is quite clear in most instances that they are clearly associated with and help perpetuate poverty. A major reason for this is that in many endemic areas the presence and impact of these diseases are not known due to the lack of investigation and information thus policymakers are not aware of their burden and benefits of their control. Documentation is also needed to help increase awareness of the international community and hopefully result in financial and technical support being made available. Thus, burden assessments of cysticercosis and echinococcosis provide an essential evidence base for securing political will and financial and technical support as well as providing a basis for cost-benefit analysis of prevention and control efforts. In order to make an appropriate and full burden assessment one must consider the health, agricultural, social and other impacts of these parasitic zoonoses comprehensively. During the symposium presentations were given concerning current ongoing initiatives to assess the burden of cysticercosis and echinococcosis and examples of the impact of these diseases in both developing and developed countries were provided. In addition, cost factors related to vaccines for these cestode diseases were discussed and the possibilities for technical and financial support from multilateral agencies for assessments and interventions presented.
Assuntos
Cisticercose/veterinária , Equinococose/veterinária , Doenças dos Suínos/parasitologia , Taenia solium/fisiologia , Animais , Efeitos Psicossociais da Doença , Cisticercose/economia , Cisticercose/parasitologia , Equinococose/economia , Equinococose/parasitologia , Equador , África do Sul , Suínos , Doenças dos Suínos/economiaRESUMO
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.
Assuntos
Neurocisticercose/diagnóstico , HumanosRESUMO
OBJECTIVE: To determine the prevalence and risk factors associated to pig cysticercosis in a rural community of Veracruz, Mexico. MATERIAL AND METHODS: Swine cysticercosis was diagnosed by tongue palpation and circulating antibodies in pigs kept in 178 household backyards. Risk factors were assessed by interviewing owners to collect information on pig breeding conditions and demographic characteristics. RESULTS: None of the 53 pigs studied showed cysts in the tongue, nor antibodies against Taenia solium in Western blot assays. Latrines were available in 91% of the houses and pigs were kept in restrained areas. CONCLUSIONS: The present study shows that pig breeding under restraint with basic hygiene and sanitary conditions, may be effective and practical interventions to restrain Taenia solium in rural communities.
Assuntos
Cisticercose/prevenção & controle , Higiene , Suínos , Animais , Anticorpos Anti-Helmínticos/análise , Western Blotting , Cruzamento , México , Fatores de Risco , População Rural , Taenia/imunologiaRESUMO
An intervention study with mass treatment against taeniasis to prevent neurocysticercosis due to Taenia solium in a rural community in Mexico was performed in 1991-96. Information and biological samples were obtained at the beginning of the study, at 6 months and at 42 months after mass treatment with praziquantel at a single dose of 5 mg/kg. Prevalence rates of taeniasis were measured by the detection of Taenia coproantigens and Taenia eggs in faeces; neurocysticercosis was suggested by clinical data and by serum antibodies in humans and also in swine. A reduction of 53% after 6 months and of 56% after 42 months for human taeniasis was seen after treatment. Late-onset general seizures decreased 70%. Anti-cysticercus antibodies in the human population were reduced by 75% after 42 months. Antibodies in pigs also showed a significant reduction of 55% after 6 months. In conclusion, an impact of mass chemotherapy against taeniasis to control cysticercosis in the short and long term was demonstrated. Praziquantel for tapeworm treatment should not be given at doses lower than 10 mg/kg. Late-onset convulsive crisis and specific antibodies are good indicators of neurocysticercosis and of exposure to the parasite, respectively.
Assuntos
Anti-Helmínticos/uso terapêutico , Neurocisticercose/prevenção & controle , Praziquantel/uso terapêutico , Teníase/tratamento farmacológico , Zoonoses , Adolescente , Adulto , Idoso , Animais , Criança , Pré-Escolar , Feminino , Humanos , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Prevalência , Suínos , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/transmissãoRESUMO
A two-phase study was conducted in a rural community in Honduras, to evaluate the association between neurocysticercosis (NCC) diagnosed by computed tomography (CT), epilepsy, seropositivity for antibodies to the cysticerci of Taenia solium [determined by enzyme-linked-immunoelectrotransfer-blot (EITB) assays], intestinal infection with this parasite, and various epidemiological factors. Of the 480 individuals studied in the first phase, 17% were seropositive and 2.5% supplied faecal samples which contained T. solium eggs. In the second phase, 148 individuals (74 of the seropositive subjects from the first phase and 74 matched controls from the seronegatives) underwent CT and neurological examinations. The CT results appeared normal in 110 (74%) of the 148, showed anatomical abnormality in seven (5%), and active or calcified lesions compatible with NCC in 31 (23% of the seropositives and 19% of the seronegatives). Only five of the latter had neurological symptoms (two being epileptics) and only five lived in households in which intestinal taeniasis had been detected. Subject age was significantly associated with NCC-compatible lesions but all the other factors investigated, including seropositivity, showed no significant association with the CT findings. The overall sensitivity of the EITB assays was found to be 55%. Taken together, the present results indicate that, even though it is a valuable tool in determining transmission levels in sero-epidemiological studies, the EITB assay should not be used to predict the existence of NCC or to estimate the prevalence of NCC. The results do provide further evidence that taeniasis and cysticercosis are widely prevalent in Honduras, and indicate that much larger studies of hyper-endemic communities may be necessary if the factors associated with the transmission of T. solium are to be elucidated.
Assuntos
Intestinos/parasitologia , Taenia , Teníase/diagnóstico , Teníase/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Anticorpos Anti-Helmínticos/sangue , Estudos de Casos e Controles , Criança , Pré-Escolar , Cisticercose/diagnóstico , Cisticercose/epidemiologia , Ensaio de Imunoadsorção Enzimática/métodos , Fezes/parasitologia , Feminino , Honduras/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Neurocisticercose/diagnóstico , Neurocisticercose/epidemiologia , Contagem de Ovos de Parasitas , Prevalência , Estudos Soroepidemiológicos , Tomografia Computadorizada por Raios XRESUMO
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.
Assuntos
Epilepsia/epidemiologia , Neurocisticercose/epidemiologia , Adolescente , Adulto , Animais , Anticorpos Anti-Helmínticos/análise , Criança , Pré-Escolar , Cysticercus/imunologia , Cysticercus/isolamento & purificação , Equador/epidemiologia , Ensaio de Imunoadsorção Enzimática , Epilepsia/diagnóstico por imagem , Epilepsia/etiologia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Neurocisticercose/complicações , Neurocisticercose/diagnóstico por imagem , Vigilância da População , Prevalência , População Rural , Tomografia Computadorizada por Raios XRESUMO
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.
Assuntos
Neurocisticercose/epidemiologia , Adolescente , Animais , Criança , Equador/epidemiologia , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Immunoblotting , Masculino , Neurocisticercose/diagnóstico , Taenia , Tomografia Computadorizada por Raios X , População UrbanaRESUMO
A comprehensive study was undertaken in a rural community in the state of Morelos, Mexico to evaluate health education as an intervention measure against Taenia solium. An educational program was developed to promote recognition and knowledge of the transmission of the parasite and to improve hygienic behavior and sanitary conditions that foster transmission. The effects of educational intervention were evaluated by measuring changes in knowledge and practices and prevalence of human taeniasis and swine cysticercosis before and after the campaign. The health education strategy was implemented with the active participation of the population based on the information obtained from a sociologic study. A questionnaire was designed and used before, immediately after the intervention, and six months later. Statistically significant improvements occurred in knowledge of the parasite, its life cycle, and how it is acquired by humans; however, changes in behavior related to transmission were less dramatic and persistent. The prevalences of cysticercosis in pigs at the start of the education intervention were 2.6% and 5.2% by lingual examination and antibody detection (immunoblot assay), respectively, and approximately one year after the intervention they were 0% and 1.2% (P < 0.05). These changes were accompanied by significant reductions in the reported access of pigs to sources of infection and freedom to roam. We conclude that health education, developed along with community involvement, reduced opportunities for transmission of T. solium in the human-pig cycle.
PIP: Neurocysticercosis is an important health problem in Mexico, as well as in many other countries of Latin America, Asia, and Africa where conditions permit completion of the cestode's life cycle in pigs and humans. A study was conducted in a rural community in the state of Morelos, Mexico, to determine whether health education could be an effective measure against Taenia solium. An educational program was developed with community input to promote recognition and knowledge of the transmission of the parasite and to improve hygienic behavior and sanitary conditions which foster transmission. The effects of the educational intervention were then assessed by measuring changes in knowledge, practices, and the prevalence of human taeniasis and swine cysticercosis before and after the campaign. Statistically significant improvements occurred with regard to knowledge of the parasite, its life cycle, and how it is acquired by humans. However, changes in behavior related to transmission were less marked and persistent. Lingual examination and antibody detection found cysticercosis among 2.6% and 5.2% of pigs, respectively, at the start of the intervention. At approximately 1 year after the intervention, prevalences had declined to 0% and 1.2%. The decline was accompanied by significant reductions in the reported access of pigs to sources of infection and freedom to roam.
Assuntos
Cisticercose/veterinária , Educação em Saúde , Doenças dos Suínos/prevenção & controle , Teníase/prevenção & controle , Animais , Anticorpos Anti-Helmínticos/sangue , Antígenos de Helmintos/análise , Cisticercose/epidemiologia , Cisticercose/prevenção & controle , Coleta de Dados , Ensaio de Imunoadsorção Enzimática , Fezes/parasitologia , Comportamentos Relacionados com a Saúde , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Immunoblotting/veterinária , Incidência , México/epidemiologia , Prevalência , População Rural , Suínos , Doenças dos Suínos/epidemiologia , Taenia/imunologia , Taenia/isolamento & purificação , Teníase/diagnóstico , Teníase/epidemiologiaRESUMO
Taenia solium cysticercosis is a major public health problem in several areas of the world. While the disease has a recognized etiologic agent, its definitive histological diagnosis is not possible in most cases because this parasite tends to lodge in cerebral tissues where routine biopsy is not feasible. Therefore, the diagnosis of human cysticercosis (and neurocysticercosis) should rest on the proper interpretation of the patients' symptoms together with data provided by radiological studies and immunologic tests for the detection of anticysticercal antibodies. Unfortunately, the pleomorphism of this parasitic disease creates confusion when non-specific clinical, radiological, or immunologic criteria alone are used to detect cases among populations or to diagnose hospitalized patients with neurological manifestations. We propose a chart of diagnostic criteria for human cysticercosis that objectively permit clinicians and health care workers to evaluate clinical, radiological, immunologic, and epidemiologic data of patients. The chart uses four degrees of criteria: absolute, major, minor, and epidemiologic, that were selected on the basis of their individual diagnostic strength. Interpretation of such criteria will result in three categories of diagnostic certainty: definitive, probable and possible, according to the likelihood that cysticercosis is present in a given person.
Assuntos
Cisticercose/diagnóstico , Doenças do Sistema Nervoso/diagnóstico , Doenças do Sistema Nervoso/parasitologia , Cisticercose/complicações , Humanos , Doenças do Sistema Nervoso/etiologiaRESUMO
Intractable headaches have been described as the presenting complaint of many patients with T. solium neurocysticercosis. We conducted a house-to-house neuroepidemiological survey of 2,723 residents of an Andean community, known to be endemic for this infection. Migraine headaches were confirmed in 187 cases (68.7 per thousand), and tension headaches were diagnosed in 77 cases (28.3 per thousand). Fifty-seven migraine sufferers accepted computed tomography examination, and in 19 it revealed neurocysticercosis. In 11 out of 52 migraineurs who had their blood drawn, electron immunotransfer blot testing (EITB) was positive for anticysticercal antibodies. In a computer-generated random sample of this community, 109 headache-free individuals were examined by CT, and 87 had EITB. Of the 109 subjects examined by CT, 14 were positive for cysticercosis. Of the 87 individuals tested by EITB, 7 were positive. A statistically significant difference between the symptom-free general population and the migraine patients was obtained for both CT (odds ratio 3.39, P < 0.005) and EITB (odds ratio 3.07, P < 0.05) diagnosis of neurocysticercosis. Neurocysticercosis appears to be a significant risk factor for the presentation of migraine-type headaches in areas endemic for T. solium infection.