Various brain-eating amoebae: the protozoa, the pathogenesis, and the disease / 医学前沿

Among various genera of free-living amoebae prevalent in nature, some members are identified as causative agents of human encephalitis, in which Naegleria fowleri followed by Acanthamoeba spp. and Balamuthia mandrillaris have been successively discovered. As the three dominant genera responsible for infections, Acanthamoeba and Balamuthia work as opportunistic pathogens of granulomatous amoebic encephalitis in immunocompetent and immunocompromised individuals, whereas Naegleria induces primary amoebic meningoencephalitis mostly in healthy children and young adults as a more violent and deadly disease. Due to the lack of typical symptoms and laboratory findings, all these amoebic encephalitic diseases are difficult to diagnose. Considering that subsequent therapies are also affected, all these brain infections cause significant mortality worldwide, with more than 90% of the cases being fatal. Along with global warming and population explosion, expanding areas of human and amoebae activity in some regions lead to increased contact, resulting in more serious infections and drawing increased public attention. In this review, we summarize the present information of these pathogenic free-living amoebae, including their phylogeny, classification, biology, and ecology. The mechanisms of pathogenesis, immunology, pathophysiology, clinical manifestations, epidemiology, diagnosis, and therapies are also discussed.

Amebíase no contexto da emergência: análise do perfil de internações e morbimortalidade nos Estados brasileiros em 5 anos / Amebiasis in the context of emergency: an analysis of the profile of hospitalizations and morbidity/mortality in the states of Brazil in 5 years

Objetivo: Trazer um panorama atualizado acerca dos índices de internações e mortalidade por amebíase nos últimos 5 anos pelo sistema de saúde público brasileiro. Métodos: As informações analisadas foram pesquisadas no banco de dados do Departamento de Informática do Sistema Único de Saúde, considerandose as seguintes variáveis: amebíase; internações e mortalidade; sexo; faixa etária; e período de 2012 a 2016. Resultados: De 14.268 internações por amebíase em todo o Brasil, 4.252 foram em 2012, 3.248 em 2013, 2.552 em 2014, 2.033 em 2015 e 2.183 em 2016. Na Região Norte, encontraram-se os dois Estados com maior e menor número de internações da região e do país: o Pará, com 4.379 casos, e Roraima, com 5. Na Região Nordeste, o Maranhão foi o Estado com mais notificações (4.114) e o segundo maior do Brasil. Na Região Sudeste, Minas Gerais apresentou maior número de registros (793); no Sul, foi o Paraná (325) e, no Centro-Oeste, Goiás (731). Dos Estados com registro de mortalidade, na Região Norte, o Amazonas obteve maior valor (1,02); no Nordeste, foi o Sergipe (5,26); no Sudeste, o Rio de Janeiro (7,81); no Sul, o Rio Grande do Sul (5,26); e, no Centro-Oeste, o Mato Grosso (1,22). Conclusão: Apesar de uma redução no número de internações, as estatísticas para a amebíase ainda continuam altas, principalmente, considerando- se que se trata de uma patologia que poderia ser evitada. É necessário investir em mais medidas educativas, que ensinem a população a evitar a contaminação pelo Entamoeba spp., bem como que seja promovidas ações de saneamento básico e abastecimento de água potável adequados para todas as regiões do Brasil. (AU)

Objective: To provide an updated picture of the hospitalization rates, and mortality due to amebiasis in the last 5 years in the Brazilian public health system. Methods: The information analyzed was searched in the Informatics Department of the Unified Health System database, considering the following variables: amebiasis; hospitalizations and mortality; gender; age group; and period from 2012-2016. Results: Of 14,268 hospitalizations for amebiasis throughout Brazil, 4,252 were in 2012, 3,248 in 2013, 2,552 in 2014, 2,033 in 2015, and 2,183 in 2016. In the North Region, there were the two states with the highest and lowest number of hospitalizations in the region and in the country: the state of Pará, with 4,379 cases, and of Roraima with 5. In the Northeast region, the state of Maranhão was the one with more notifications (4,114), and the second largest one in Brazil. In the Southeast region, the stat of Minas Gerais presented the highest number of records (793); in the South region, it was the state of Paraná (325); and in Center-West, Goiás (731). Of the states with mortality records, in the North region Amazonas reached the highest value (1.02); in the Northeast, Sergipe (5,26); in the Southeast, Rio de Janeiro (7.81); in the South, Rio Grande do Sul (5.26); and in the Center-West region, Mato Grosso (1,22). Conclusion: Despite a reduction in the number of hospitalizations, the statistics for amebiasis are still high, mainly considering that it is a pathology that could be avoided. It is necessary to invest in more educational measures, which teach the population how to avoid contamination by Entamoeba spp., as well as to promote basic sanitation actions, and drinking water supply suitable for all regions of Brazil. (AU)

Seroprevalence of acanthamoeba antibodies in rheumatoid arthritis patients by IFAT, Tehran, Iran 2007

This preliminary study was conducted to discriminate the prevalence of Acanthamoeba antibodies in rheumatoid arthritis [RA] patients and healthy controls to analyze the correlation between these two groups. From October 2006 to August 2007 a total of 121 serum samples from RA patients attending the Rheumatolgy Department at Shariati Hospital in Tehran were obtained and stored at -20°C until using by indirect fluorescent-antibody test [IFAT]. RA was diagnosed according to the American Collage of Rheumatology classification criteria. The organism used in this study was isolated from various water resources in Tehran, Iran cultured axenically and then went on a PCR assay based on 18S rRNA to identify the genus Acanthomoeba. Indirect immunofluorescence antibody [IFA] staining of serum samples was carried out to detect anti Acanthomoeba antibodies. In culture, out of 22 samples, 13 [59%] were grown in xenic but only two in axenic medium. PCR amplified a 904bp fragment, specific for Acanthamoeba. Of examined serum samples, Acanthamoeba antibodies were present in 70 [57.8%] and 52 [41.2%], respectively. The highest titer of antibodies [1:320] was detected in one patient with RA. Our study supports the hypothesis that some parasitic microorganisms can involve and contribute toward the development of rheumatoid syndromes

Amebíase e epidemiologia / Amebiasis and epidemiology

A infecção por Entamoeba histolytica, identificada há mais de 130 anos por Fedor A. Lesh, existe praticamente em todo o mundo e é hoje considerada uma DST - com relação à transmissão é a doença dos cinco efes: finger, feces, flies, fomites e fornication. A epidemiologia da amebíase na cidade do Rio de Janeiro (Brasil), estudada por um de nós (R.M.), parece confirmar o lugar de infecção no rol das doenças sexualmente transmissíveis. Epidemiologia é o estudo da ocorrência de uma doença - estudos epidemiológicos podem influenciar a vida de populações inteiras. O estudo de Framingham (EUA), a investigação de Sharr sobre a doença dos legionários e o trabalho de John Snow sobre a cólera são exemplos clássicos de estudos epidemiológicos que mudaram o comportamento e estilos de vida.

Entamoeba histolytica infection was identified more than 130 years ago, has worldwide occurrence and nowadays is considered a sexually transmitted disease (STD). Regarding transmission is considered as the five Fs disease: finger, feces, flies, fomites and fornication. Rio de Janeiro city amebiasis epidemiology was studied by one of us and seems to confirm its place on STD list. Epidemiology consists on the study of the disease occurrence - epidemiological studies can influence an entire population life. Framinghan (EUA), Legionnaire's disease Sharr investigation and John Snow cholera study are classic examples of epidemiological studies that changed behaviour and lifestyle.

The role of domestic tap water in Acanthamoeba contamination in contact lens storage cases in Korea

A survey was carried out from August to December 2004 in Pusan, Korea to document the presence of free-living amoeba (FLA), including the genus Acanthamoeba, in both contact lens storage cases and domestic tap water. Acanthamoeba was isolated from 5 (4.2%) in 120 contact lens storage cases. Four house tap water samples from residents, whose contact lens storage cases had been contaminated by Acanthamoeba, were also found to be contaminated with Acanthamoeba. Therefore, the contamination rate of FLA and Acanthamoeba in domestic tap water was investigated in order to examine the role of domestic tap water in Acanthamoeba contamination of contact lens storage cases. FLA and Acanthamoeba were identified in 97 (46.8%) and 16 (7.7%) of the 207 domestic tap water samples, respectively. There were no significant differences between the contamination rates of FLA in tap water according to the filtration plant of origin. No FLA was detected in the tap water directly supplied by the water purification plants. Water storage tanks appear to promote FLA colonization, including Acanthamoeba, in domestic tap water. This increases the risk of Acanthamoeba contamination in contact lens storage cases as well as increasing the risk of Acanthamoeba keratitis.

A status survey of common water-borne diseases in desert city Bikaner (NW Rajasthan, India).

Water is scarce and, in general, a low quality resource in desert areas and the Indian desert is no exception. With this in view, the present study was taken up to survey the status of common water-borne diseases epidemiological trends in the desert city Bikaner (NW Rajasthan). In the city, 15.5 per cent population and 44.5 per cent families were found to suffer from one or more common water-borne diseases including amoebiasis, diarrhoea, dysentery, jaundice and typhoid. No case of fluorosis was recorded. The highest incidence was that of diarrhoea (5.4 per cent population). The worst affected and safe zones in the city were identified and the trends of different diseases in different zones of the city are discussed. The highest incidence of diseases was noted during summer (58.8 per cent) followed by winter (34.1 per cent) and monsoon (7.0 per cent). Relationship of diseases with population attributes like age, education, economy and family size are also discussed. Attributes for contamination of drinking water have been tried to identify and safety measures suggested.

effect of breast feeding on amoebiasis, giardiasis, and cryptosporidiosis in children below the age of two years

To determine the effect of breast feeding on amoebiasis, giardiasis and cryptosporidiosis in infants in our region. Stool samples were collected from 180 children below 2 years of age who suffered from acute diarrhea. There were 81 breast fed, 49 bottle fed, and 50 mixed bottle and breast fed children. The direct smear method and then formalin-ether sedimentation were carried out to detect intestinal parasites. Fecal smears were prepared from the sediment and stained by the modified Ziehl-Neelsen method for the recovery of acid-fast oocysts of Cryptosporidium. Intestinal amoebiasis, giardiasis and cryptosporidiosis were found at the highest rates [53%, 55% and 64% respectively] among bottle fed children. Collectively, 16.3% of the bottle fed children with diarrhea tested positive for parasitic infections. Breast feeding appears to reduce the risk of these parasitic infections and should be encouraged

Distribution of pathogenic Naegleria spp in Thailand.

Research concerning the distribution, isolation, viability, ultrastructure, morphology and immunogenicity of Naegleria fowleri has been increasing in Thailand during 1988-2000. The distribution of the organism was carried out from 1985 to 1987 in Si Sa Ket and Ubon Rachathani Provinces, after the first fatal case was reported in Si Sa Ket. Since then in a 1998 survey of N. fowleri in stagnant water around industrial areas was carried out in Pathum Thani, Samut Prakan and Lopburi provinces. The results showed that 10% of pathogenic Naegleria belonged to species fowleri as characterized by morphology and the occurrence of pathogenesis in mice after nasal inoculation. In the same year, Nacapunchai et al (1999) determined the prevalence of amebae in aquatic habitat of human environments in five parts of Thailand during the summer. Fourteen percent of free living Naegleria spp were found in both soil and water resources. Recent studies of the ultrastructure, factors affecting the viability and SDS-PAGE electrophoretic patterns of 3 Thai strains of pathogenic Naegleria spp indicated their similarities in morphological characteristics of pathogenic reference control, Naegleria fowleri CDC VO 3081. Additional study using a genetic approach to species criteria using allozyme electrophoresis had been conducted.

Estado actual de la amibiasis / Actual statement of the amebiasis

Objetivo. Realizar una investigación documental bibliográfica y epidemiológica para valorar la situación actual de la amibiasis, en especial su comportamiento biológico, su morbilidad, mortalidad y modalidades de terapia médico/quirúrgico. Metodología. Inicialmente se realiza una revisión documental bibliográfica, para ubicar la situación epidemiológica nacional en el contexto internacional. Posteriormente se realiza una investigación epidemiológica en base de la revisión de 20 años que permite establecer el canal endémico en el Estado de México; para finalizar, analizando los alcances que ha tenido el grupo de investigadores mexicanos en el Centro de Estudios sobre Amibiasis. Conclusiones: el grupo médico en nuestro país ha logrado grandes avances en el abatimiento de la morbilidad de la amibiasis, sin lograr erradicarla, puesto que corresponde a los grandes planes nacionales y la introducción de medidas drásticas de saneamiento ambiental hecho único que abatiría por completo la presencia de la amibiasis en México

Incidencia de giardia lambia y ameba histolítica en niños menores de 10 años vistos en la consulta externa del Hospital Luis M. Morillo King, La Vega, enero-marzo 1997 / Incidence of giardia lambia and amoeba hystolitica in kids under 10 years of age seen at the external consult service of the \"Luis Morillo King\" Hospital, La Vega, January-March 1997

En la intención de determinar la incidencia de giardias lambias y amebas histolíticas en los pacientes que comprendidos en edades de 0-10 años acudieron a la consulta pediátrica del hospital Luis Manuel Morillo King, La Vega, fueron estudiados 864 pacientes en el módulo de consultas externas resultando 345 (40//) afectados por parasitosis intestinal. De estos 183 (53//) padecían amebiasis y/o giardiasis, correspondiendo (47//) 162 casos a otros parásitos como áscaris, oxiuros, tenias, entre otros. De los 183 pacientes positivos por amebiasis y/o giardiasis 104 (56.8//) pertenecían a zona rural y 79 (43.2//) a la urbana, consultando sólo 85 pacientes (46.4//) por motivos relacionados con el tracto gastrointestinal

Amebiasis in schistosomiasis endemic and non-endemic areas in Egypt

Stool and blood specimens were collected from each of 404 and 576 individuals at Sindbis Village [Qalyoubia Governorate] in the Nile Delta, where schistosomiasis is endemic, and El-Rashda Village [New Valley Governorate] in the Western Desert of Egypt where there is no schistosomiasis, respectively. The prevalence of infection with entamoeba [E. histolytica and/or E. dispar] was higher at Sindbis than at El-Rashda Village. Serum antibodies developed only against E. histolytica. Only 16 - 17% of those who were positive microscopically can be considered infected with E. histolytica as determined serologically. At Sindbis, the prevalence of E. histolytica infection was lower in S. mansoni negative than in S. mansoni positive individuals

La amibiasis y el absceso hepático amibiano en México, un problema de salud pública de actualidad / The amebiasis and the amebic liver abscess in Mexico, a present time public health problem

Antecedentes: La amibiasis continúa siendo un problema de salud pública a nivel mundial. En México es un motivo de consulta frecuente y tan sólo en el Instituto Mexicano del Seguro Social se atienden más de medio millón de casos al año. La información epidemiológica en México es aún incompleta. Objetivo: Describir el comportamiento secular de la amibiasis en todas sus formas de presentación clínica y del abseco hepático amibiano, en la población mexicana y en la amparada por IMSS-Solidaridad. Métodos: Se realizó un estudio ecológico de tendencia. Se graficaron las tasas de incidencia de la amibiasis en todas sus formas, así como del absceso hepático amibiano por cada uno de los años de período analizado. Resultados: La incidencia de amibiasis en todas sus formas mostró una tendencia estable en el período de estudio, situación similar a lo observado con el absceso hepático amibiano. La amibiasis es más frecuente durante el primer año de vida. Por el contrario, el absceso hepático amibiano muestra un patrón de "J" invertida, es decir, la ocurrencia es mayor en los extremos de la vida. La letalidad ha mostrado una tendencia al descenso constante: Conclusiones: La amibiasis en México es un reflejo de las condiciones socioeconómicas y de la cultura inacabada mexicana. Es necesario propiciar la educación para la salud, al igual que el mejor diagnóstico y detección de portadores asintomáticos. Con las madres portadoras debieran redefinirse las políticas de salud, dada la elevada frecuencia de amibiasis y absceso hepático amibiano en los menores de un año.

Prevalence of intestinal parasitic infection among children in two villages in Lao PDR.

The prevalence of intestinal parasitic infection among 128 children under 15 years old in two villages in Khammouane Province, southeastern Lao PDR, was investigated. Overall prevalence of helminth infection was 77.3%; the prevalence was 64.8% in children under 6 years, 88.5% in those aged 6-10 years and 81.8% in the age group above 11 years. The prevalent helminths found in the subjects were Ascaris lumbricoides (48.4%), Trichuris trichiura (43.8%), hookworm (37.5%) and Opisthorchis viverrini (37.5%). Intestinal protozoan infection was demonstrated in 14.1%; Giardia lamblia was the most prevalent (8.6%) protozoan species.

Entamoeba histolytica: fecal antigen capture immunoassay for the diagnosis of enteric amebiasis by a monoclonal antibody

A amebiase mantem sua importancia epidemiologica em paises subdesenvolvidos onde sua prevalencia a converteu na parasitose de maior morbidade e mortalidade apos malaria e esquistossomose. Em regra, tanto o diagnostico clinico como os levantamentos epidemiologicos assentam na identificacao microscopica de cistos e/ou trofozoitos em extractos fecais. Este procedimento requer pessoal muito bem treinado, e laborioso, e frequentemente fornece resultados contraditorios. Para obviar estas dificuldades, no presente trabalho montamos uma tecnica de diagnostico imunoenzimatico baseado na captura de um antigeno de 96 kDa presente nas fezes de individuos infectados pela E. hystolytica (COPROELISA-Eh). Triplicatas de 117 amostras fecais processadas pelo metodo de concentracao formol eter foram definidas como positivas ou negativas por tres microscopistas especialistas em amebiase...