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.

Relato de caso na pediatria: meningite eosinofílica / Eosinophilic meningitis: a pediatric case report

Contexto: Meningite eosinofílica é uma doença aguda que afeta o sistema nervoso central. Foi reportada pela primeira vez no Brasil em 2007 e se tornou uma doença emergente, antes restrita a países da Ásia e ilhas do Pacífico. Objetivos: O objetivo deste trabalho é relatar o caso de meningite eosinofílica em uma criança atendida no serviço de pediatria de um hospital universitário do Paraná e revisar esse diagnóstico diferencial raro. Achados: Criança de 1 ano e 11 meses de idade, residente na cidade de Curitiba, que foi admitida no serviço de pronto atendimento pediátrico com história de febre persistente e diária associada à cefaleia. À admissão, criança pouco reativa, prostrada e afebril, com força muscular preservada, pupilas isocóricas fotorreagentes, sem rigidez de nuca. À punção liquórica apresentou 79% eosinofilia. Principais conclusões: Fica claro a importância da segurança alimentar, para garantir a qualidade tanto na produção quanto no manuseio dos produtos alimentícios e evitar a ocorrência de novos casos semelhantes a este

Introduction: Eosinophilic meningitis is an acute disease that affects the central nervous system. It was first reported in 2007 in Brazil and has become an emerging disease, previously restricted to countries in Asia and the Pacific islands. Objectives: The aim of this study is to report the case of eosinophilic meningitis in a child treated at the pediatric service of a university hospital in Paraná and to review this rare differential diagnosis. Case Description: Child, 1 year and 11 months old, resident in the city of Curitiba, who was admitted to the pediatric emergency service with a history of daily persistent fever associated with headache. Upon admission, a little reactive, prostrate and afebrile child, with preserved muscle strength, photoreactive isochoric pupils, without terminal neck stiffness. The CSF puncture showed 79% eosinophilia. Conclusion: The etiological identification allows the application of preventive and therapeutic measures effective in the control of meningitis

Encefalitis por amebas de vida libre: herramientas actuales para el diagnóstico y tratamiento tempranos / Free-living amoeba encephalitis: current tools for early diagnosis and treatment

Introducción: Naegleria fowleri, Acanthamoeba spp. y Balamuthia mandrillaris son amebas de vida libre que producen daños sustanciales del sistema nervioso central y cuyo diagnóstico premortem es poco frecuente. Objetivo: Proveer una visión general de los aspectos clínico-epidemiológicos y las posibilidades diagnósticas más eficaces en la meningoencefalitis amebiana primaria y la encefalitis granulomatosa amebiana, así como las experiencias de tratamiento expuestas en la literatura reciente. Métodos: Se realizó una revisión bibliográfica sobre las amebas de vida libre. Se analizó la información obtenida de artículos científicos en la base de datos Google Scholar®, PubMed y las citas relacionadas por el programa en PubMed Central. Análisis y síntesis de la información: En primer término del análisis de la meningoencefalitis amebiana primaria y la encefalitis granulomatosa amebiana, resalta la diferenciación de sus características clínicas y epidemiológicas, también que el líquido cefalorraquídeo presenta gran relevancia para el diagnóstico de la meningoencefalitis amebiana primaria. Sin embargo, para los casos presuntivos de la encefalitis granulomatosa amebiana el examen del líquido cefalorraquídeo depende de la valoración riesgo-beneficio y se ha obtenido mayor positividad con el diagnóstico histopatológico de biopsias premortem. En general, se acrecienta la implementación de la investigación del ADN por diferentes métodos que brindan certeza de cada una de las especies de AVL causantes de enfermedad neurológica. El aislamiento en cultivo confirmatorio de N. fowleri, Acanthamoeba spp. y B. mandrillaris presenta diferencias en la factibilidad de crecimiento en diversos medios de acuerdo con la especie y limitaciones adicionales. Conclusiones: La mortalidad asociada con las infecciones del sistema nervioso central por amebas de vida libre permanece alta, aunque varios estudios brindan experiencias útiles a partir de los casos de pacientes que han sobrevivido. Resulta importante tener en cuenta que el diagnóstico rápido de la infección es clave para un tratamiento exitoso(AU)

Introduction: Naegleria fowleri, Acanthamoeba spp. and Balamuthia mandrillaris are free-living amoebae of infrequent premortem diagnosis which cause substantial damage to the central nervous system. Objective: To provide an overview of the clinical-epidemiological aspects and the most effective diagnostic possibilities in primary amebic meningoencephalitis and granulomatous amebic encephalitis, as well as their treatment experiences in recent publications.. Methods: A bibliographic review was conducted about free-living amoebae. An analysis was performed of data obtained from scientific papers published in the databases Google Scholar and PubMed, and the citations listed by the PubMed Central program. Data analysis and synthesis: As principal term of the analysis of primary amebic meningoencephalitis and amebic granulomatous encephalitis, the differentiation of their clinical and epidemiological characteristics stands out, also that cerebrospinal fluid is highly relevant for the diagnosis of primary amebic meningoencephalitis. However, for presumptive cases of amoebic granulomatous encephalitis, the examination of cerebrospinal fluid depends on the risk-benefit assessment and greater positivity has been obtained with the histopathological diagnosis of premortem biopsies. In general, the implementation of DNA research by different methods provided accurate information about each one of the free-living amoeba species that cause neurological disease. Confirmatory culture isolation of N. fowleri, Acanthamoeba spp. and B. mandrillaris revealed growth feasibility differences between diverse media depending on the species and additional limitations. Conclusions: Mortality associated to central nervous system infections caused by free-living amoebae remains high. Studies describing cases of patients who have survived constitute useful material. It is important to bear in mind that fast diagnosis of the disease is crucial to treatment success(AU)

Spectrum of CNS infections in the Philippines

@#The CNS Infection Censuses for 2011 and 2012 from 9 neurology training programs in 7 institutions in the Philippines were collated to determine the types of CNS infections seen in the country and their relative frequencies. A comparison with a similar survey done in 1999 was made. A total of 1629 cases of CNS infections were recorded. There were 23 categories. Bacterial meningitis (34.3%) and TB meningitis (30.7%) were the top two infections, constituting more than half of all CNS infections seen. When the adult and pediatric census were separated, TB meningitis came up to be the most common infection in adults (43%) with bacterial meningitis a poor second at 19.4%. The reverse is seen in the pediatric population – bacterial meningitis (41.7%) vs. TB meningitis (24.6%). Cryptococcal meningitis was more frequent in the adult census (8.1%) compared with the pediatric census (0.1%). These patterns were seen in a similar census done in 1999. A significant increase in relative frequency in cryptococcal cases was seen in the later census (2.8% vs. 2.0%), the increase being due to the marked increase in the adult group (8.1% vs. 4.3%), probably due to the upward trend in the incidence of HIV cases in the country. No increase in this category was seen in the pediatric population. The benefits of collaboration among institutions in coming up with a large number of cases of CNS infections and a greater variety to study was highlighted. The study was conducted by the CNS Infection Council of the Philippine Neurological Association.

Meningoencephalitis due to Naegleria fowleri in cattle in southern Brazil / Meningoencefalite por Naegleria fowleri em um bovino no sul do Brasil

Abstract Naegleria fowleri is a free-living amoeba commonly found in the environment, mainly in fresh water and soil. This protozoon is occasionally involved in cases of fatal central nervous system disease in humans and other animal species. We describe here a case of meningoencephalitis due to Naegleria fowleri in cattle, in southern Brazil. A four-year-old Angus cow presented a clinical history of initial mild neurological signs that progressed to paddling movements, opisthotonus and lateral recumbency after five days. This animal had been kept in an irrigated rice stubble paddock. Grossly, the main lesions consisted of multiple areas of malacia in the right olfactory bulb, piriform lobes, hippocampus, frontal lobe cortex and fornix, along with severe thickening of the mesencephalon and rhombencephalon leptomeninges. Microscopically, severe multifocal necrosuppurative and hemorrhagic meningoencephalitis associated with a large quantity of amoebic trophozoites was present. The latter were confirmed to be Naegleria spp., through immunohistochemistry. Based on the strong congruence with the histopathological data of known cases reported in the literature, a probable association with Naegleria fowleri was established. To our knowledge, this is only the second report of Naegleria fowleri-associated meningoencephalitis in cattle in South America, and it is the first in southern Brazil.

Resumo Naegleria fowleri é uma ameba de vida livre, comumente encontrada no meio ambiente, principalmente em água doce e no solo. Este protozoário é ocasionalmente associado a casos fatais de doença do sistema nervoso central em seres humanos e espécies animais. No presente trabalho, um caso de meningoencefalite por Naegleria fowleri em um bovino na região sul do Brasil é descrito. Uma vaca Angus, de quatro anos de idade apresentou histórico clínico caracterizado inicialmente por sinais neurológicos leves que progrediram para movimentos de pedalagem, opistótono e decúbito lateral após cinco dias. Este animal era mantido em um piquete em resteva de arroz irrigado. Macroscopicamente, as principais lesões foram caracterizadas por múltiplas áreas de malacia no bulbo olfatório direito, lobos piriformes, hipocampo, córtex do lobo frontal e no fórnix, bem como acentuado espessamento das leptomeninges do mesencéfalo e rombencéfalo. Microscopicamente, meningoencefalite necrossupurativa e hemorrágica associada à grande número de trofozoítos amebianos foram observadas. Estes foram confirmados como Naegleria spp. através de imuno-histoquímica. Baseado na forte congruência apresentada entre os dados histopatológicos provenientes de casos conhecidos publicados na literatura, uma provável associação com Naegleria fowleri foi estabelecida. O presente trabalho trata-se do segundo relato de meningoencefalite associada à Naegleria fowleri em bovinos na América do Sul e o primeiro na região sul do Brasil.

Primary Amebic Meningoencephalitis: A Case Report

Primary amebic encephalitis (PAM) is a devastating central nervous system infection caused by Naegleria fowleri, a free-living amoeba, which can survive in soil and warm fresh water. Here, a 43-year-old healthy male was exposed to warm freshwater 5 days before the symptom onset. He rapidly developed severe cerebral edema before the diagnosis of PAM and was treated with intravenous conventional amphotericin B while died of terminal cerebral hernia finally. Comparing the patients with PAM who has similar clinical symptoms to those with other common types of meningoencephalitis, this infection is probably curable if treated early and aggressively. PAM should be considered in the differential diagnosis of purulent meningoencephalitis, especially in patients with recent freshwater-related activities during the hot season.

Enfermedad de Chagas en el sistema nervioso central en paciente con infección por VIH: dificultades diagnósticas y terapéuticas / Chagas disease in the central nervous system in patient infected with HIV: diagnostic and therapeutic difficulties

Chagas disease (ChD), caused by the protozoan Trypanosoma cruzi, is an endemic anthropozoonosis in Latin America, linked to deficients socio-economic and cultural aspects and is considered one of the neglected tropical diseases. We report a fatal case of Chagas disease reactivation with central nervous system involvement in a patient with HIV infection, whose diagnosis was confirmed by positive PCR (polymerase chain reaction) test of blood, with treatment response efficiency with benznidazol and management and etiologic treatment was difficult due to limited number of antitrypanosomal drugs and the occurrence of frequent and serious adverse effects.

La enfermedad de Chagas, causada por el protozoo Trypanosoma cruzi, es una antropo-zoonosis endémica en Latinoamérica, vinculada con aspectos socio-económico-culturales deficitarios y considerada una de las enfermedades desatendidas. Presentamos un caso fatal de una reactivación de la enfermedad de Chagas con afectación del sistema nervioso central en un paciente con infección por VIH. El diagnóstico se confirmó por reacción de polimerasa en cadena (RPC) positiva en sangre. Tuvo una buena respuesta al tratamiento con benznidazol. Las dificultades en el manejo del tratamiento etiológico se debieron al número limitado de medicamentos antitripanosomiásicos y la aparición de efectos adversos graves.

Enfermedad de Chagas del sistema nervioso central en un paciente con SIDA demostrada por métodos cuantitativos moleculares / Chagas disease affecting the central nervous system in a patient with AIDS demonstrated by quantitative molecular methods

Although infrequent, Trypanosoma cruzi reactivation is possible among patients with HIV/AIDS infection that develop a tumor-like or granulomatous lesion in the CNS. We report the case of a 60 years old male patient with HIV/AIDS and low CD4 lymphocytes count with cerebellar symptoms and mild paresis, associated to supra and infratentorial hypodense lesions and positive serology tests both to T. gondii and Trypanosoma cruzi. Empirical therapy against toxoplasmosis was prescribed together with antiretroviral therapy but without a favorable response. Brain Chagas disease was confirmed by quantitative PCR in the CSF but he died despite nifurtimox treatment. Despite its rare occurrence, Chagas disease affecting the CNS is possible among patients with HIV/AIDS infection. Epidemiological exposure, a positive Chagas serological test and the image pattern of brain lesions support the suspicion. Diagnosis can be confirmed by molecular test in CSF samples, including new quantitative methods. Despite an adverse prognosis, specific therapy can be attempted besides antiretroviral treatment.

La reactivación de la infección por Trypanosoma cruzi es un diagnóstico infrecuente pero posible en pacientes con infección por VIH/SIDA y una lesión de tipo tumoral o granulomatosa en el sistema nervioso central. Presentamos el caso clínico de un paciente de 60 años con VIH/SIDA y recuentos bajos de linfocitos CD4, con síntomas cerebelosos y paresia leve, lesiones hipodensas supra e infratentoriales y serología positiva para Toxoplasma gondii y T. cruzi. Se trató empíricamente como una toxoplasmosis cerebral y con terapia antiretroviral, sin respuesta clínica. La enfermedad de Chagas cerebral se confirmó por RPC cuantitativa en el LCR. El paciente falleció a pesar de recibir terapia con nifurtimox. Apoyan la posibilidad de un Chagas cerebral en pacientes con VIH/SIDA, la exposición epidemiológica, la serología positiva y el patrón de distribución de las lesiones en las imágenes. El diagnóstico puede mejorarse con técnicas moleculares cuantitativas en LCR. A pesar de su mal pronóstico, se puede intentar una terapia específica junto al tratamiento antiretroviral.

Toxoplasmosis intramedular en una paciente con coinfección por VIH y tuberculosis / Intramedullary toxoplasmosis in HIV-tuberculosis co-infected patient

The most common clinical presentation of Toxoplasma gondii in HIV patients is encephalitis; however, the intramedullary involvement has been reported in a few cases. We report a case of intramedullary toxoplasmosis in a female patient diagnosed with HIV/tuberculosis co-infection, and history of poor adherence to antiretroviral therapy. The patient developed subacute paraparesis with compromise of sensory function and urinary sphincter. The nuclear magnetic resonance evaluation showed a single intramedullary ring-enhanced lesion at the T-8 level which was solved after an anti-Toxoplasma therapy with trimethoprim/sulfamethoxazole.

El compromiso encefálico por Toxoplasma gondii en pacientes con VIH es la localización más frecuente, no obstante, la localización intramedular ha sido escasamente reportada. Comunicamos un caso de toxoplasmosis intramedular en una mujer con diagnóstico de coinfección por VIH y tuberculosis, con mala adherencia a la terapia antirretroviral, que desarrolló de forma subaguda un cuadro de paraparesia con compromiso sensitivo y de esfínteres. La resonancia magnética mostró una lesión única intramedular con captación de contraste periférico en anillo a nivel T-8, que se resolvió tras recibir tratamiento anti-toxoplasmosis con cotrimoxazol.

Amebas de Vida Libre aisladas en aguas superficiales del municipio de Turbaco, Bolívar-Colombia / Free-living amoebae isolated from surface water in the municipality of Turbaco, Bolívar, Colombia

Introducción: las amebas de vida libre (AVL) han sido aisladas de hábitat incluyendo: agua, suelo y vegetación. Los cambios ecológicos y la incursión de estos hábitats, han hecho que puedan invadir un hospedero y vivir como parásitos dentro de él. Por esto, las especies de los géneros Acanthamoeba y Naegleria han sido asociadas con infecciones oportunistas. Objetivo: evaluar la presencia de las amebas de vida libre en fuentes de agua natural en el municipio de Turbaco, con el fin de que sean consideradas en la conducta diagnóstica y terapéutica por las entidades de salud pertinentes. Métodos: se realizó un estudio descriptivo, transversal en los arroyos Matute, Mameyal y Cucumán del municipio de Turbaco - Bolívar. La identificación se hizo mediante el estudio de los frescos de las fuentes de agua observando características morfológicas de las amebas. Resultados: de un total de 54 muestras se obtuvo una positividad del 55,5 por ciento para una o más AVL. Con mayor frecuencia Naegleria sp con un 44,4 por ciento y Acanthamoeba sp, en un 7,4 por ciento. Además, se encontraron otros microorganismos responsables de parasitosis intestinales como: Giardia intestinalis, Blastocystis hominis y Retortomonas intestinalis. Conclusión: los arroyos estudiados son hábitat de las AVL, demostrando que están presentes en el ambiente y que son frecuentes en zonas donde el ser humano suele practicar ciertas actividades, sin embargo, la proporción de Naegleria sp. permite alertar aún más a la población puesto que esta ameba puede afectar a todo tipo de individuo independiente de su estado inmunológico(AU)

Introduction: free-living amoebae (FLAs) have been isolated from habitats such as water, soil and vegetation. As a result of ecological changes and incursion into these habitats, free-living amoebae have invaded hosts and settled within them as parasites. This is the reason why the species of genera Acanthamoeba and Naegleria have been associated with opportunistic diseases. Objective: determine the presence of free-living amoebae in natural water sources from the municipality of Turbaco, so they are taken into account by the corresponding health institutions in the design of diagnostic and therapeutic actions. Methods: a descriptive cross-sectional study was conducted of streams Matute, Mameyal and Cucumán in the municipality of Turbaco, Bolívar. Identification was based on the study of fresh water from the sources selected and observation of the morphological characteristics of amoebae. Results: of the total 54 samples, 55.5 percent tested positive for one or more FLAs. The most common were Naegleria sp with 44.4 percent and Acanthamoeba sp with 7.4 percent. Microorganisms were also found which cause intestinal parasitic disease, such as Giardia intestinalis, Blastocystis hominis and Retortomonas intestinalis. Conclusion: the streams studied are habitats for FLAs, showing that the latter are present in the environment and are common in areas where human beings perform certain activities. However, the proportion of Naegleria sp. makes it necessary to emphatically alert the population, since this amoeba may affect all individuals, irrespective of their immune status(AU)

A Fatal Case of Naegleria fowleri Meningoencephalitis in Taiwan

After bathing at a hot spring resort, a 75-year-old man presented to the emergency department because of seizure-like attack with loss of conscious. This is the first case of primary amebic meningoencephalitis (PAM) caused by Naegleria fowleri in Taiwan. PAM was diagnosed based on detection of actively motile trophozoites in cerebrospinal fluid using a wet-mount smear and the Liu's stain. The amoebae were further confirmed by PCR and gene sequencing. In spite of administering amphotericin B treatment, the patient died 25 days later.

Primary amoebic meningo encephalitis- a case study

Primary amoebic meningoencephalitis [PAM] mimicks acute bacterial meningitis in presentation. However because it is very rare as compared to pyogenic meningitis, physicians may miss the diagnosis initially. Recent exposure to diving, swimming or splashing in warm fresh water should suggest the possibility of amoebic meningoencephalitis, and prompt examination of the cerebrospinal fluid [CSF] for N. Fowleri. Timely diagnosis requires a high index of suspicion in any individual presenting with acute onset of meningitis-like symptoms. We present a fatal case of PAM masquerading as an acute upper respiratory infection but a quick transition to pyogenic meningitis, and encephalitis

Demostración del ameboflagelado Naegleria fowleri como agente etiológico de meningoencefalitis amébica primaria en Santiago de Cuba / Demonstration of flagellum ameba Naegleria fowleri as etiological agent of primary amebic meningoencephalitis in Santiago de Cuba

En los últimos años se ha demostrado que el amebo-flagelado Naegleria fowleri es el causante de la meningoencefalitis amébica primaria (MEAP). En Cuba ha sido mencionada la sospecha de su presencia en un líquido céfalo-raquídeo (LCR) de una ameba cuya locomoción y circunstancias sugería que pudiera ser esta ameba. Se realizó el análisis en fresco y en cultivo, con Test de Flagelación de 64 muestras de LCR seleccionadas al azar a partir de las 173 que presentaron las características de transparencia y negatividad a bacterias, requisitos iniciales en búsqueda de este agente, partiendo de una muestra inicial de 1 488 muestras de LCR procedentes de pacientes con meningoencefalitis clínicamente establecidas. De estos 64 LCR, 2 resultaron positivos a la evaluación por los diferentes métodos lo que permitió teñirlos con Giemsa, demostrar su capacidad de flagelación y su resistencia a TMT. Las características citoquímicas de los líquidos concordaban con lo planteado en la literatura y uno de los pacientes sobrevivió, el otro falleció. La patogenicidad de los ameboflagelados aislados de esas dos muestras de LCR se comprobó en el modelo animal ratón albino suizo y fueron observados al microscopio electrónico. Lo anterior confirma microbiológicamente por primera vez en el país este agente etiológico, aunque ya había elementos clínicos y de laboratorio de sospecha en casos anteriores

During the last years it has been demonstrated that the flagellae-carring ameba Naegleria fowleri is the aethiologic agent of the primary amoebic meningoencephalitis (PAME), in Cuba the suspicion of its presence has been mentioned in a Cefalo Raquideal Fluid (CRF) of an ameba whose locomotion and circumstances suggested that it could be this organism. The present work carries out the analysis in fresh CRF samples and after culture, performing the Flagelation Test of the 64 CRF that presented the characteristics of transparency and negativity to bacterial culture ,needed to suspicion of this flagellae-carring ameba, leaving of an starting sample of 1488 CRF.From this analysed sample of CRF only two were positive to the observation of amebas what allowed to tint them with Giemsa and also with Lugol, to demonstrate their flagelation capacity and their resistance to TMT in the corresponding test. The citochemical characteristics of the liquids agreed with that outlined in the literature for this organisms,and one of the patients survived, the other one died. The patogenicity of the isolated flagellae-carring amebas was proven in the animal model of Swiss albino mouse and both isolated strains were observed by the electronic microscope. This results are the basis for considering the present report the first one confirming N.Fowleri as aetiologic agent in two cases of PAME in Cuba

Hallazgo de acanthamoeba spp en biopsia cerebral de un paciente con adenocarcinoma metastásico / Acanthamoeba spp found in a cerebral biopsy from a patient with metastasic adenocarcinoma

Las amibas de vida libre (AVL) del género Acanthamoeba son parásitos facultativos ampliamente distribuidos en el ambiente, por lo cual el contacto del humano con ellos es frecuente, sin embargo, los reportes de enfermedades producidas por AVL son escasos. La gravedad de éstas justifica su búsqueda, sobre todo cuando la infección es del sistema nervioso central (SNC) y cuando hay compromiso in munológico. En este trabajo se reporta el hallazgo de Acanthamoeba spp en una biopsia cerebral, tomada a un paciente de 44 años de edad con adenocarcinoma. Se exa minó la muestra bajo el protocolo del Laboratorio de Amibiasis, de la Cátedra de Parasitología, Escuela de Bioanálisis, Facultad de Medicina, Universidad Central de Venezuela, para la investigación de AVL y Entamoeba histolytica. Se realizó examen directo y coloraciones especiales, inducción de la flagelación y cultivos a diferentes temperaturas. Se observó crecimiento de Acanthamoeba spp en el medio de Page modificado por Chinchilla y col. (1979), incubado a 37 °C a las 96 horas. La descripción morfológica coincide con la morfología del grupo 3 de Acanthamoeba, según Visvesvara (1991). Se destaca la importancia de la realización del cultivo para el crecimiento e identificación de estos organismos en aquellos laboratorios donde los métodos basados en biología molecular aun no se hayan implementado como parte del diagnóstico y así aplicar el tratamiento oportuno y específico al paciente.

Free-living amoebas (FLA) of genus Acanthamoeba are parasitic facultative organisms whose are widely distributed in the environment, thus the human contact with them is frequent; nevertheless, there are few reports of diseases produced by FLA. The severity of these diseases justifies its re search, mainly when the infection is at central nervous system (CNS) and when there is an immunocompromised host. This work reports the finding of Acanthamoeba spp in a cerebral biopsy from a 44 year-old patient with adenocarcinoma. We followed the protocol established by the Amibiasis Laboratory, Parasitology Chair, School of Bioanalisis, Medicine Faculty, Central University of Venezuela, for the investigation of FLA and Entamoeba histolytica. It wasmade by direct examination of the sample and special stains, flagellation induction and cultures incubated at different temperatures. We observed Acanthamoeba spp growth in biphasic Page media modified by Chinchilla and col. (1979), incubated for 96 hours at 37 °C. The morphologic des cription agrees with the morphology of group 3 of Acanthamoeba, according to Visvesvara (1991). We emphasize the importance of using growth culture for isolation and identification of these organisms in those laboratories where molecular methods has not been implemented yet as part of the diagnosis scheme and thus for applying the opportune and specific treatment to the patient.

Neurological involvement in visceral leishmaniasis: case report / Envolvimento neurológico na leishmaniose visceral: relato de caso

Visceral leishmaniasis is a severe and potentially fatal vector-borne disease. The most typical symptoms are fever, hepatosplenomegaly, weight loss, bleeding and bacterial infections. Neurological changes are rarely reported. This paper describes a child who presented with neurological signs as the first symptoms of leishmaniasis; tone was diminished and tremors in the extremities were observed. A diagnosis of visceral leishmaniasis was confirmed by parasite detection in the bone marrow. Symptoms were reversed by specific treatment. The nature of a possible mechanism of neurological involvement in visceral leishmaniasis remains unexplained.

A leishmaniose visceral é uma doença severa e potencialmente fatal transmitida pela picada de flebótomos infectados pelo parasita. Os sintomas mais comuns incluem febre, hepatoesplenomegalia, perda de peso, sangramentos e infecções bacterianas. Alterações neurológicas têm sido raramente descritas nesses pacientes. Descrevemos aqui o caso de uma criança que desenvolveu um quadro de infecção pela Leishmania, tendo como principal sintoma tremor de extremidades. O diagnóstico da doença foi confirmado pela demonstração do parasita no aspirado de medula. Os sintomas foram revertidos pelo tratamento específico. A natureza do possível mecanismo do envolvimento neurológico na leishmaniose visceral permanece duvidoso.

Plasmodium vivax malaria presenting with severe thrombocytopenia, cerebral complications and hydrocephalus.

Two cases of a one and 4 year old child of plasmodium vivax malaria are reported in association with CNS complications. Both presented with encephalopathy and seizures. One had severe thrombocytopenia, massive intracranial bleed and hydrocephalus requiring shunt surgery while the other had gastrointestinal manifestations, encephalopathy and hydrocephalus. Both responded to quinine but are left with sequelae.

Astrocytic and microglial response and histopathological changes in the brain of horses with experimental chronic Trypanosoma evansi infection / Resposta astrocítica e microglial e alterações histopatológicas no sistema nervoso central de eqüinos infectados cronicamente com Trypanosoma evansi

This study aimed to characterize astrocytic and microglial response in the central nervous system (CNS) of equines experimentally infected with T. evansi. The experimental group comprised males and females with various degrees of crossbreeding, ages between four and seven years. The animals were inoculated intravenously with 10(6) trypomastigotes of T. evansi originally isolated from a naturally infected dog. All equines inoculated with T. evansi were observed until they presented symptoms of CNS disturbance, characterized by motor incoordination of the pelvic limbs, which occurred 67 days after inoculation (DAI) and 124 DAI. The animals in the control group did not present any clinical symptom and were observed up to the 125th DAI. For this purpose the HE histochemical stain and the avidin biotin peroxidase method was used. Lesions in the CNS of experimentally infected horses were those of a wide spread non suppurative meningoencephalomyelitis.The severity of lesions varied in different parts of the nervous system, reflecting an irregular distribution of inflammatory vascular changes. The infiltration of mononuclear cells was associated with anisomorphic gliosis and reactive microglia was identified. The intensity of the astrocytic response in the CNS of the equines infected by T. evansi characterizes the importance of the performance of these cells in this trypanosomiasis. The characteristic gliosis observed in the animals in this experiment suggests the ability of these cells as mediators of immune response. The parasite, T. evansi, was not identified in the nervous tissues.

Este estudo objetivou caracterizar a participação astrocítica e microglial no sistema nervoso central (SNC) de eqüinos experimentalmente infectados com T. evansi. O grupo experimental foi formado por machos e fêmeas com vários graus de cruzamentos e idade variando entre quatro e sete anos. Os animais foram inoculados com 10(6) tripomastigotas de T. evansi, originalmente isolada de um cão infectado naturalmente. Todos os eqüinos inoculados foram observados até o aparecimento dos sintomas neurológicos, caracterizados por incoordenação motora dos membros pélvicos, o qual ocorreu entre 67 e 124 dias após a inoculação (DPI). Os animais do grupo controle não apresentaram sinais clínicos e foram observados até o 125º DPI. Para este propósito, foram utilizados os métodos histoquímicos (HE) e imunoistoquímicos do complexo avidina-biotina peroxidase (ABC). A lesão no sistema nervoso central (SNC) dos eqüinos infectados com T. evansi foi caracterizada como meningoencefalomielite não supurativa. A gravidade das lesões variou em diferentes segmentos do SNC, refletindo distribuição irregular das alterações vasculares. Infiltrado perivascular e meníngeo foi associado a gliose anisomórfica e microgliose reativa. A intensidade da resposta astrocítica no SNC dos equinos infectados com T. evansi caracteriza a importância da performance destas células nas tripanossomíases. A gliose observada nos animais deste experimento sugerem a habilidade destas células como mediadoras da resposta imune. T. evansi não foi identificado no parênquima do SNC.