Pathogenic Acanthamoeba (Hartmanella)

Culbertson, C. G.; Overton, W. M.; Reveal, Mildred A.

doi:10.1093/ajcp/35.3.195

Cited by 77 publications

(19 citation statements)

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“…Mo dificações no meio am biente podem in ter ferir n a relação parasito-hospedeiro. O assunto será discutido, em maiores Culbertson 1961Culbertson , 1963Culbertson , 1964) has shown th a t the normally free-living "limax am oeba" Acanthamoeba, can enter m am m als (mice and monkeys) by the nasal cavity, penetrate the mucosa and cause severe lesions in the brain, lungs and elsewhere. I t seems as thcugh Acanthamoéba m ay be in the process of beconrng adapted to a truly endoparasitic existence in m am m als; an exam -Ü 3 V .…”

Section: Segundo Alguns Autores Esses Flagelamentioning

confidence: 99%

O fenômeno parasitismo

Ferreira¹

1973

Rev. Soc. Bras. Med. Trop.

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Luiz F e rn a n d o F e rre ira ** "A t ali leveis of organization, the outcome of the interplay between two individuais is ãe-term ined not only by their intrinsic endowments but also and even more, by the conditions under which they come into contact". René Dubos "Infectious disease is the result of much more than the mere collision of an infectious agent w ith a potencial host". H . J . Simon I -O ENFOQUE ECOLÓGICO O ser vivo como meio ambienteOs autores modernos têm procurado de finir o fenômeno parasitism o em termos ecológicos, o organismo de um ser vivo sendo um h ab itat, que pode ser utilizado por outro ser vivo. O processo em suas linhas gerais é sem elhante ao que ocorre na adaptação ao meio físico. Dentro dessa linha, Levine ((40) define a parasitologia como: " . . . b ra n d i of ecology in which one organism is the environm ent for ano ther" . A mesma idéia vamos encontrar em Noble e Noble (49): " . . . one m ight consider the parasit in an organ of the host as a ccm m unity. . . the latter being the externai environm ent of the community" ou em Huff e col. (32): "one area oí ecology deals with systems of biotic relations, systems in which one organism lives on or in another in order to obtain sustenance" .No trabalho de Barreto (4) encontra mos: "O corpo de um ser vivo, digamos de um anim al superior, para maior faci lidade de compreensão, oferece nichos po tenciais p ara outros organismos. Eles in vadem aquele, quer à procura de alim en to, quer em busca de abrigo, quer para obter am bas as coisas" .O enfoque ecológico no estudo do p a rasitismo tem m estrado um a enorme ri queza de conseqüências. No seu processo de evolução, os seres vivos se têm adap tado às mais diferentes condições do meio am biente. Assim, como foi possível a pas sagem da vida aquática para terrestre, da mesma m aneira que o homem se tem * T ra b a lh o do L ab o rató rio de P a ra sito lo g ia do I n s t it u t o P re sid e n te C astello B ranco -F u n d a ç ã o I n s ti t u t o O sw aldo C ruz. ** P ro fesso r T itu la r d e P arasito lo g ia.R ecebido p a ra p u b lic a ç ã o em 24.4.1973. Condições como a tem peratura, por exemplo, da mesma m aneira que afeta a distribuição das espécies de vida livre, também interfere em relação às espécies parasitas. A parasitem ia em Rana catesbeiana infectada por Trypanosoma rotatorium é profundam ente influenciada pela tem peratura. Observações antigas, já 'haviam m ostrado a sua im portância na resistência da galinha e da rã, ao tétano e ao carbúnculo. Barrow (5) cham a a atenção para a influência da tem peratura na infecção da salam andra pelo Trypa nosoma diemyctili.Assim como em am bientes em que há carência de alim ento as populações vão apresentar determ inadas alterações, o mes mo vai acontecer com os anim ais p arasitos. K nauft e W arren (35) estudaram o efeito do déficit proteico e calórico no p a rasito e no hospedeiro, em camundongos infectados com S. mansoni. Nas dietas deficitárias, observaram diminuição nas posturas do verme, e assinalam que as grandes deficiências ca...

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Section: Segundo Alguns Autores Esses Flagelamentioning

confidence: 99%

O fenômeno parasitismo

Ferreira¹

1973

Rev. Soc. Bras. Med. Trop.

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“…Acanthamoeba spp. (9,21), Balamuthia mandrillaris (54), and Naegleria fowleri (59), can proliferate in drinking water-related biofilms at elevated temperatures (36). In addition, Legionella pneumophila, the main etiologic agent of Legionnaires' disease (12), which proliferates in freshwater at temperatures above 25°C (57), is frequently observed in these environments (14,31,39).…”

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Relationships between Free-Living Protozoa, Cultivable Legionella spp., and Water Quality Characteristics in Three Drinking Water Supplies in the Caribbean

Valster

Wullings

Berg

et al. 2011

Appl Environ Microbiol

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The study whose results are presented here aimed at identifying free-living protozoa (FLP) and conditions favoring the growth of these organisms and cultivable Legionella spp. in drinking water supplies in a tropical region. Treated and distributed water (؎30°C) of the water supplies of three Caribbean islands were sampled and investigated with molecular techniques, based on the 18S rRNA gene. The protozoan host Hartmannella vermiformis and cultivable Legionella pneumophila were observed in all three supplies. Operational taxonomic units (OTUs) with the highest similarity to the potential or candidate hosts Acanthamoeba spp., Echinamoeba exundans, E. thermarum, and an Neoparamoeba sp. were detected as well. In total, 59 OTUs of FLP were identified. The estimated protozoan richness did not differ significantly between the three supplies. In supply CA-1, the concentration of H. vermiformis correlated with the concentration of Legionella spp. and clones related to Amoebozoa predominated (82%) in the protozoan community. These observations, the low turbidity In tropical regions, the water temperature in drinking water distribution system is permanently about 30°C (4). In these regions, free-living protozoa (FLP), serving as hosts for pathogenic bacteria, including Acanthamoeba spp. (1, 38), Hartmannella spp. (37), and Naegleria spp. (38, 49), have been observed in surface water, wastewater, cooling towers, and drinking water (3,5,19,45). Certain FLP with pathogenic properties, viz. Acanthamoeba spp. (9, 21), Balamuthia mandrillaris (54), and Naegleria fowleri (59), can proliferate in drinking water-related biofilms at elevated temperatures (36). In addition, Legionella pneumophila, the main etiologic agent of Legionnaires' disease (12), which proliferates in freshwater at temperatures above 25°C (57), is frequently observed in these environments (14,31,39).FLP in aquatic environments feed on bacteria, fungi, other protozoa, and organic detritus in biofilms and sediments or in the planktonic phase (32). The abundance of prey organisms and detritus depends on the water composition and the hydraulic conditions in distribution systems, which therefore also affect both the FLP abundance and community composition (52, 55). Most information on community composition and abundance of FLP in freshwater environments has been obtained by using cultivation methods and microscopy. Recently, however, the presence and identities of such organisms in drinking water supplies in temperate regions have been studied by using molecular methods for detection and identification (33, 51). In two groundwater supplies in the Netherlands a total of 127 operational taxonomic units (OTUs) of FLP were identified based on their 18S rRNA gene sequences. FLP, mostly pathogens, have been characterized in only a few studies in tropical regions (3,5,19). In recent reviews it was concluded that more research is needed to determine which factors favor the growth of these organisms in water supplies (47,48).Cases of Legionnaires' disease have been reporte...

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“…Furthermore, certain free-living protozoa are human pathogens, e.g., Naegleria fowleri (81), Balamuthia mandrillaris (77), and Acanthamoeba spp. (12) can cause encephalitis. Acanthamoeba spp.…”

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confidence: 99%

Free-Living Protozoa in Two Unchlorinated Drinking Water Supplies, Identified by Phylogenic Analysis of 18S rRNA Gene Sequences

Valster

Wullings

Bakker³

et al. 2009

Appl Environ Microbiol

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Free-living protozoan communities in water supplies may include hosts for Legionella pneumophila and other undesired bacteria, as well as pathogens. This study aimed at identifying free-living protozoa in two unchlorinated groundwater supplies, using cultivation-independent molecular approaches. For this purpose, samples (<20°C) of treated water, distributed water, and distribution system biofilms were collected from supply A, with a low concentration of natural organic matter (NOM) (<0.5 ppm of C), and from supply B, with a high NOM concentration (7.9 ppm of C). Eukaryotic communities were studied using terminal restriction fragment length polymorphism and clone library analyses of partial 18S rRNA gene fragments and a Hartmannella vermiformis-specific quantitative PCR (qPCR). In both supplies, highly diverse eukaryotic communities were observed, including free-living protozoa, fungi, and metazoa. Sequences of protozoa clustered with Amoebozoa (10 operational taxonomic units [OTUs]), Cercozoa (39 OTUs), Choanozoa (26 OTUs), Ciliophora (29 OTUs), Euglenozoa (13 OTUs), Myzozoa (5 OTUs), and Stramenopiles (5 OTUs). A large variety of protozoa were present in both supplies, but the estimated values for protozoan richness did not differ significantly. H. vermiformis was observed in both supplies but was not a predominant protozoan. One OTU with the highest similarity to Acanthamoeba polyphaga, an opportunistic human pathogen and a host for undesired bacteria, was observed in supply A. The high level of NOM in supply B corresponded with an elevated level of active biomass and with elevated concentrations of H. vermiformis in distributed water. Hence, the application of qPCR may be promising in elucidating the relationship between drinking water quality and the presence of specific protozoa.Free-living protozoa are ubiquitous in natural freshwater environments (7,38,51,71) but also proliferate in engineered water systems, including water treatment systems (3,47,70), distribution systems (6, 75), and tap water installations inside buildings (54, 69). Concentrations of protozoa, determined using cultivation methods and microscopy, range from Ͻ1 to 10 4 cells liter Ϫ1 in treated water (3,47,70,75) and from Ͻ1 to 7 ϫ 10 5 cells liter Ϫ1 in distribution systems (6,61,64,75). Genera of free-living protozoa commonly observed in these systems and in tap water installations include Acanthamoeba,

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Pathogenic Acanthamoeba (Hartmanella)

Cited by 77 publications

References 0 publications

O fenômeno parasitismo

O fenômeno parasitismo

Relationships between Free-Living Protozoa, Cultivable Legionella spp., and Water Quality Characteristics in Three Drinking Water Supplies in the Caribbean

Free-Living Protozoa in Two Unchlorinated Drinking Water Supplies, Identified by Phylogenic Analysis of 18S rRNA Gene Sequences

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