Molecular epidemiological study of hand, foot, and mouth disease in a kindergarten-based setting in Bangkok, Thailand

Hand, foot, and mouth disease (HFMD) is a contagious childhood illness and annually affects millions of children aged less than 5 years across the Asia-Pacific region. HFMD transmission mainly occurs through direct contact (person-to-person) and indirect contact with contaminated surfaces and objects. Therefore, public health measures to reduce the spread of HFMD in kindergartens and daycare centers are essential. Based on the guidelines by the Department of Disease Control, a school closure policy for HFMD outbreaks wherein every school in Thailand must close when several HFMD classrooms (more than two cases in each classroom) are encountered within a week, was implemented, although without strong supporting evidence. We therefore conducted a prospective cohort study of children attending five kindergartens during 2019 and 2020. We used molecular genetic techniques to investigate the characteristics of the spreading patterns of HFMD in a school-based setting in Bangkok, Thailand. These analyses identified 22 index cases of HFMD (symptomatic infections) and 25 cases of enterovirus-positive asymptomatic contacts (24 students and one teacher). Enterovirus (EV) A71 was the most common enterovirus detected, and most of the infected persons (8/12) developed symptoms. Other enteroviruses included coxsackieviruses (CVs) A4, CV-A6, CV-A9, and CV-A10 as well as echovirus. The pattern of the spread of HFMD showed that 45% of the subsequent enteroviruses detected in each outbreak possessed the same serotype as the first index case. Moreover, we found a phylogenetic relationship among enteroviruses detected among contact and index cases in the same kindergarten. These findings confirm the benefit of molecular genetic assays to acquire accurate data to support school closure policies designed to control HFMD infections

The use of high-resolution (1)H nuclear magnetic resonance (NMR) spectroscopy in the clinical diagnosis of Acanthamoeba

Acanthamoeba are opportunistic protozoan pathogens that can produce sight-threatening keratitis and fatal granulomatous encephalitis. The successful prognosis requires early diagnosis and differentiation of pathogenic Acanthamoeba spp. followed by aggressive treatment regimen. In this study, we tested the use of high-resolution (1)H NMR spectroscopy in the clinical diagnosis of Acanthamoeba. Using NMR spectroscopy combined with Pattern Recognition Analysis (PRA), we analysed variations in the biochemical 'fingerprint' of invasive and non-invasive Acanthamoeba, its closely related genus, Balamuthia mandrillaris, neuropathogenic Escherichia coli K1 strain E44, a laboratory strain of E. coli K-12, HB101, mammalian cells including human brain microvascular endothelial cells and monkey kidney cells. The findings revealed significant variations in the metabolites of amoebae, mammalian cells and bacteria. Interestingly, (1)H NMR spectra provided distinct biochemical profiles of clinical and non-clinical Acanthamoeba isolates highlighting the potential of (1)H NMR spectroscopy combined with PRA for the development of a novel diagnostic test that could rapidly identify pathogenic Acanthamoeba isolates with high sensitivity and specificity

Genotyping and phylogenetic analysis of Acanthamoeba isolates associated with keratitis

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