Pneumocystis pneumonia is an opportunistic disease caused by invasion of unicellular fungus Pneumocystis jirovecii. Initially, it was responsible for majority of morbidity and mortality cases among HIV-infected patients, which later have been reduced due to the introduction of anti-retroviral therapy, as well as anti-Pneumocystis prophylaxis among these patients. Pneumocystis pneumonia, however, is still a significant cause of mortality among HIV-negative patients being under immunosuppression caused by different factors, such as transplant recipients as well as oncologically treated ones. The issue of pneumocystosis among these people is particularly emphasized in the article, since rapid onset and fast progression of severe symptoms result in high mortality rate among these patients, who thereby represent the group of highest risk of developing Pneumocystis pneumonia. In contrast, fungal invasion in immunocompetent people usually leads to asymptomatic colonization, which frequent incidence among healthy infants has even suggested the possibility of its association with sudden unexpected infant death syndrome. In the face of emerging strains with different epidemiological profiles resulting from genetic diversity, including drug-resistant genotypes, the colonization phenomenon desires particular attention, discussed in this article. We also summarize specific and sensitive methods, required for detection of Pneumocystis invasion and for distinguish colonization from the disease.
IntroductionThe pathologic relevance of Demodex infestation in blepharitis is still controversial. The aim of the study was to determine the prevalence of Demodex spp. in eyelash follicles and its relationship to eye symptoms.Material and methodsA total of 290 individuals were studied for the presence of Demodex folliculorum and Demodex brevis within eyelash follicles. Participants belonged to one of four groups: inpatients, drug abusers, health professionals, and medical students. Ten eyelashes were epilated from each subject, placed on microscope slides and examined for parasites. The sample was defined as positive if at least one parasite or parasite's ova were present. The presence of parasites was analyzed according to age, gender, place of living, reported eye problems, and use of contact lenses or glasses.ResultsThe prevalence of Demodex spp. infestation among all studied subjects was 41%, with the highest infestation rate among inpatients (p < 0.01) and elderly people (p < 0.001). No difference regarding the presence of Demodex was found between women and men (p = 0.76). Demodex folliculorum was about 2.4 times more frequent than D. brevis. The prevalence of Demodex spp. in subjects with and without eye complaints suggesting blepharitis was similar (41.6% vs. 40.2%, respectively, p = 0.9). On the other hand, wearing glasses was linked to Demodex infestation (48.4% vs. 32.3%, p < 0.01).ConclusionsDemodex is a common saprophyte found in human eyelash follicles. Its presence might be related to some ocular discomfort; however, in the vast majority of cases the infestation seems to be asymptomatic.
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