Ácaros del género Demodex: ¿parásitos colonizadores de personas sanas o asociados a patología ocular? / Demodex genus: colonizing parasites of healthy people or mites associated with ocular pathology?

Las especies Demodex folliculorum y Demodexbrevis, responsables de la demodicosis humana, afectan la piel y en ocasiones están vinculadas con afecciones oculares. El objetivo de este trabajo fue conocer si existe asociación significativa entre la presencia del ácaro y de patologías palpebrales, y el papel de factores como la edad y el sexo de los pacientes. Se analizaron las pestanas de un conjunto de pacientes sintomáticos y asintomáticos (n = 72) de entre 9 y 82 años. El 53% de los pacientes fueron positivos para la presencia del ácaro Demodex. De ellos, el 66% manifestó síntomas o patologías oculares, dentro de las cuales la blefaritis y el ojo seco resultaron prevalentes. Se observaron asociaciones significativas tanto entre la presencia de este ácaro y una edad mayor de 60 años (p < 0,001), como entre la presencia del ácaro y ojo seco o blefaritis o ambos (p <0,001). Consideramos necesaria la búsqueda de Demodex sp. en pacientes con síndrome de ojo seco o blefaritis, especialmente durante la inmunosenescencia, a fin de instaurar tratamientos antiparasitarios específicos.

Demodex folliculorum and Demodex brevis are mites that are responsible for human demodicosis affecting skin and frequently linked to ocular diseasess. The aim of this work was to determine the association between Demodex sp. and eyelid and eyelash diseases and to establish the predisposing factors for acquiring this parasitic disease. Eyelashes from symptomatic and asymptomatic patients (n = 72) between 9 and 82 years old were analyzed, where 53% were positive for Demodex sp., of which 66% manifested ocular symptoms and pathologies, blepharitis and dry eye being prevalent. Significant correlations between Demodex and patients over 60 years of age (p <0.001) and between Demodex sp. and dry eye patients / blepharitis (p <0.001) were observed. We consider that it is necessary to search for Demodex sp. especially in those patients suffering from dry eye and blepharitis and/or during immunosenescence in order to implement specific antiparasitic treatments.

[Demodex genus: colonizing parasites of healthy people or mites associated with ocular pathology?] / Ácaros del género Demodex: ¿parásitos colonizadores de personas sanas o asociados a patología ocular?

Demodex folliculorum and Demodex brevis are mites that are responsible for human demodicosis affecting skin and frequently linked to ocular diseasess. The aim of this work was to determine the association between Demodex sp. and eyelid and eyelash diseases and to establish the predisposing factors for acquiring this parasitic disease. Eyelashes from symptomatic and asymptomatic patients (n=72) between 9 and 82 years old were analyzed, where 53% were positive for Demodex sp., of which 66% manifested ocular symptoms and pathologies, blepharitis and dry eye being prevalent. Significant correlations between Demodex and patients over 60 years of age (p<0.001) and between Demodex sp. and dry eye patients / blepharitis (p<0.001) were observed. We consider that it is necessary to search for Demodex sp. especially in those patients suffering from dry eye and blepharitis and/or during immunosenescence in order to implement specific antiparasitic treatments.

Molecular and morphological characterization of Acanthamoeba isolated from corneal scrapes and contact lens wearers in Argentina.

In this study, we describe the frequency of Acanthamoeba keratitis (AK) in patients that assisted in the Ophthalmology Department and determine the species/genotypes of free living amoebas (FLA) isolates. FLA from Corneal scrapes (CS) and contact lens (CL) wearers were studied by morphological and molecular characterization. A database was constructed with sociodemographic, clinical findings and history of use of CL variables. During January 2000 and September 2016 patients with corneal pathology admitted to the Ophthalmology Service of the University Hospital in Córdoba city, Argentina were included in the study. FLA were detected in 1.5% (11/739) and in 17% (11/65) of CS and CL analyzed respectively. FLA isolates from CL users evidenced an 80.9% of inappropriate lens maintenance, 4.8% (1/21) were not CL users that have been in contact with waters in outdoor environment and 14,3% (3/21) with no data about CL users. Acanthamoeba was confirmed in 100% and 82% of CS and LC respectively. The most frequent symptom associated with AK was red eye and photophobia. FLA from CS belonged to group II but 82% (9/11) and 18% (2/11) from CL belonged to group II and III respectively. T4 genotype and A. polyphaga species were detected in 100% of Acanthamoeba isolates. Poor CL hygiene practices, highlights the need for improved education about the severity of AK and consequences of improper CL hygiene. Genotype T4 detected in 100% of both CS and CL samples, consistently with previous findings indicating that this genotype is by far the most prevalent isolated from ocular infection.

Geographic distribution of human Blastocystis subtypes in South America.

Blastocystis is a cosmopolitan enteric protist colonizing probably more than 1 billion people. This protozoan exhibits genetic diversity and is subdivided into subtypes (STs). The aim of this study was to determine the distribution of Blastocystis STs in symptomatic and asymptomatic human samples from different countries of South America. A total of 346 fecal samples were genotyped by SSU rDNA showing ST1 (28.3%), ST2 (22.2%), ST3 (36.7%), ST4 (2%), ST5 (2.3%), ST6 (2%), ST7 (2.3%), ST8 (0.6%), ST12 (0.9%) and a novel ST (2.7%). These findings update the epidemiology of Blastocystis in South America and expand our knowledge of the phylogeographic differences exhibited by this stramenopile.

Blastocystis and urticaria: Examination of subtypes and morphotypes in an unusual clinical manifestation.

Blastocystis is a human common enteric protist that may colonize a large variety of non-human hosts linked to symptoms and diseases such as abdominal pain, constipation, diarrhea, urticaria, flatulence and irritable bowel syndrome (IBS). Blastocystis exhibits remarkable genetic diversity and multiple subtypes (STs) within the genus with no absolute associations with clinical symptomatology. Here we analyzed fecal samples from Argentinean patients (n=270) belonging to symptomatic (urticaria and non-specific gastrointestinal symptoms, n=39) and asymptomatic control (n=28). Those patients infected with Blastocystis (n=67) were submitted for morphological analysis, DNA extraction, 18S PCR, sequencing and STs identification according to DNA barcoding. Blastocystis vacuolar forms were the predominant morphotype (75%), ameboid-like forms were evidenced in 1.5% of samples. Blastocystis ST3 was detected in 71.6% (n=48), of which 71.4%, (n=35) and 28.6% (n=14) belonged to symptomatic and asymptomatic respectively. Other subtypes identified were ST1 (14.9%), ST6 (7.5%) and ST2 (5.9%). Blastocystis 18S barcoding evidenced in non-urticaria symptomatic patients and asymptomatic control group the presence of allele 134 (ST3) (p<0.0001), while allele 34 (ST3) was detected in 85.7% (18/21) of symptomatic uricaria as compared with control group (1/21) (p<0.0001). The presence of a particular allele (a34) significantly associated with urticaria patients was detected and the clinical implications of these findings are herein discussed.