Molecular Epidemiology of Enteroviruses Associated with Hand, Foot, and Mouth Disease in the Mainland of China

Hand, foot, and mouth disease （HFMD） is a common contagious illness which occurs worldwide both sporadically and in epidemics. The disease mainly affects, children and the typical symptoms, which may resolve spontaneously, include mucocutaneous papulovesicular lesions on the hands, feet, mouth, and buttocks. In rare cases, however, the patients may also develop neurological complications such as neurogenic pulmonary edema,

A comparative study on environmental surveillance of enterovirus:Using a two-phase separation method and a filtration method with a mixed cellulose ester(MCE)membrane

This study aimed to compare the sensitivity of two-phase separation and the filtration method using a mixed cellulose ester(MCE)membrane to detect enteroviruses in sewage samples.From December 2015 to July 2016,four domestic sewage samples(1 L/sample)were collected monthly from the Guangzhou Liede Sewage Treatment Plant,and each sewage sample was divided into two aliquots(500 mL).The sewage sample was concentrated using the two-phase separation and the filtration method using an MCE membrane,and the treated solutions were inoculated into cells for enterovirus isolation.Polymerase chain reaction amplification,VP1 sequencing,and enterovirus molecular typing were performed on the positive isolates.The detection rates of poliovirus(PV)and non-polio enterovirus(NPEV)obtained using the filtration method using an MCE membrane were higher than those using the two-phase separation method.McNemar's test showed that the detection rates of PV,NPEV,type 1 Sabin-like(SL1),type 2 Sabin-like(SL2),and type 3 Sabin-like(SL3)strain were not statistically significant(P>0.05).In Guangdong Province,China,the detection rates for PV and NPEV were 53.13%and 62.50%(20/32),respectively.Twenty-seven PVs were isolated,three highly variable strains of the type 1 vaccine,with seven nucleotide substitutions in the VP1 region,compared with the type 1 Sabin strains.Eighty-seven strains of NPEV were isolated and nine serotypes were identified,among which coxsackievirus B3(CVB3),echovirus 6(E6),and echovirus 11(E11)were the dominant strains.The filtration method using an MCE membrane is more sensitive than two-phase separation and can be used as a robust,sensitive,and cost-effective method to isolate enteroviruses from sewage.

Analysis of the distribution characteristics of enterovirus types based on environmental surveillance from 2013 to 2021 in Fujian Province, China

Environmental surveillance (ES) is a useful approach for monitoring circulating viruses, including polioviruses (PVs) and non-polio enteroviruses (NPEVs). In this study, the results of nine years of ES from 2013 to 2021 at six sampling sites in three cities in Fujian Province, China, were summarized. It showed that the sewage samples contained abundant viruses, but the positive rate was affected by different sampling sites. From the 520 samples, 431 PVs, 1,713 NPEVs, and 281 human adenoviruses (HAdVs) were isolated. PV isolates had been markedly affected following the adjustment of the immunization strategy. All but one PV isolate were Sabin-like strains without wild PVs. One isolate was vaccine-derived PV type 3 with 10 variation points in theVP1 region. After May 2016, PV type 2 was no longer detected, and PV type 3 became a superior serotype. Of 1,713 NPEVs, 24 serotypes were identified, including echovirus11 (E11), E6, coxsackievirus B3 (CVB3), CVB5, E7, and E3 were the predominant serotypes (37.65%, 20.96%, 11.50%, 8.87%, 8.23%, and 7.06%, respectively). The temporal dynamic of the six common serotypes was inconsistent. E3 was frequently isolated, but the number of isolates was low, with no obvious peaks. E6, E7, and CVB3 exhibited periodic changes with a high peak every three to four years, and E11 only had one high peak lasting four years. Summer-fall peaks of the echoviruses and spring-winter peaks of CVB were observed in the monthly distribution of virus isolation. The infectious isolates of various serotypes of different species identified from the sewage samples showed that ES is an essential part of pathogen surveillance.