Genetic diversity and pathogenicity of Blastocystis

Abstract

Blastocystis is a unicellular, anaerobic protist which lives in the intestinal tract of diverse animals, including humans. It was found that the host specificity and the pathogenic potential of different isolates are correlated with sequence variations in the SSU-rRNA gene. Identification of the organism to the species level is still an unresolved challenge. Genetic diversity revisions have led to the identification of 17 subtypes (STs) within the Blastocystis genus, and 9 (ST1 to ST9) have been reported in humans with varying prevalence. Since the members of the genus revealed a large genetic diversity, several molecular modalities of subtyping methods have been developed. Numerous studies on conveying the pathogenic potential to the molecular subtypes are available, but they could not be compared or analysed with the different molecular techniques employed. The use of different approaches may give false positives during diagnosis and the possibility of missed infections. A review of recent scientific literature indicates that the development of PCR assays is needed for molecular epidemiology and for mixed infections in health and disease cohorts, and also to help identify sources of Blastocystis transmission to humans, as well as to identify potential animal and environmental reservoirs. This review summarizes some of the recent progress and improvements in Blastocystis research on genetic diversity, taxonomy, molecular epidemiology, pathogenicity and subtyping methods.

Ocorrência de patógenos transmitidos por carrapatos (Anaplasma spp, Babesia spp, Ehrlichia spp, Hepatozoon spp e Rickettsia spp) em lobos guará (Chrysocyon brachyurus) e cães domésticos na região do Parque Nacional da Serra da Canastra, Minas Gerais, Brasil

“…Amblyomma parvum e A. pseudoconcolor (PACHECO et al, 2007;TOMASSONE et al, 2010b) (SKOTARCZAK, 2003). No Brasil, são relatadas as espécies E. canis e E. chaffeensis (ALMOSNY, 1998;MACHADO et al, 2006;LABRUNA et al, 2007b), sendo a E. canis de maior prevalência nos cães (ALMOSNY, 1998;TRAPP et al, 2006;AGUIAR et al, 2007a) e detectada frequentemente nos carrapatos da espécie Rhipicephalus sanguineus (AGUIAR et al, 2007a;SOUZA et al, 2010).…”

“…Essas bactérias podem causar duas doenças distintas, a Erliquiose monocítica (EM) e Ehrliquiose granulocítica (EG), acometendo tanto cães quanto humanos (WALKER; DUMLER, 1997;SKOTARCZAK, 2003 (DANTAS-TORRES, 2008a). No Brasil é considerada uma doença amplamente distribuída (DANTAS-TORRES, 2008a), com alta casuística em cães (41,3%) (LABRUNA et al, 2007b) Espírito Santo (SPOLIDORIO et al, 2010).…”

“…No Brasil há relatos de seres humanos positivos em sorodiagnóstico em Minas Gerais (CALIC et al, 2004) Anaplasmose é uma doença que acomete animais e humanos causada por bactérias intracelulares obrigatórias que infectam principalmente células granulocíticas (DUMLER et al, 2001). Existem várias espécies de importância veterinária como Anaplasma (Ehrlichia) bovis e Anaplasma marginale em bovinos (BARROS et al, 2005;BARR;UILENBERG, 2010), Anaplasma platys em cães (DANTAS-TORRES, 2008a) e Anaplasma phagocytophilum em cães, humanos, gatos e cavalos (WALKER; DUMLER, 1997;SKOTARCZAK, 2003;.…”

<b>Epidemiological aspects of tick-borne diseases in wild and domestic animals of two environmental protection areas in the city of Natal, Rio Grande do Norte State, Brazil</b>

“…Ehrlichiosis is a disease caused by obligate intracellular Gram-negative bacteria with tropism for hematopoietic cells that infects animals and humans in many parts of the world. Bacteria of the genus Ehrlichia has been divided into three groups according to their genetic similarities: genogroup "I", constituted by the species E. canis, E. chaffeensis and E. ewingii; Genogroup "II" which includes E. phagocytophila (Anaplasma phagocytophilum as reclassified), E. equi and Human granulocytic ehrlichiosis agent (HGE); and genogroup "III", formed by E. risticii and E. sennetsu SKOTARCZAK, 2003).…”

“…The monocytic ehrlichiosis (ME) is caused by E. canis (in dogs) and E. chaffeensis (human). It is transmitted by the ticks R. sanguineus and Amblyomma americanum, respectively (SKOTARCZAK, 2003). E. canis was first described in Brazil in 1973(COSTA et al, 1973, and isolation was obtained only in 2002 (TORRES et al, 2002).…”