Genetic Diversity of Coxsackievirus A16 Associated with Hand, Foot, and Mouth Disease Epidemics in Japan from 1983 to 2003

Abstract

Coxsackievirus A16 (CV-A16) and human enterovirus 71 (HEV71) are both major etiologic agents of hand, foot, and mouth disease (HFMD). The surveillance data indicate that CV-A16 and HEV71 infections independently cause large outbreaks and then become quiescent for a period of a few years (6).HEV71-related illness is more severe, with a significantly greater frequency of serious complications and fatality, than illness caused by CV-A16 (2). In 1997, deaths associated with epidemics of HEV71-associated HFMD in Sarawak, Malaysia, followed by outbreaks with high mortality in Taiwan in 1998 and 2000, raised considerable public concern about the virulence of this virus. Since then, several groups have attempted to describe the molecular epidemiology of HEV71 in the AsiaPacific region and have reported the relationships of HEV71 epidemics with the genetic diversity of HEV71 strains (1, 5, 10). The results indicate that HEV71 strains causing HFMD outbreaks were genetically changed.On the other hand, the molecular epidemiology of CV-A16 associated with HFMD epidemics has not been fully described (9). In the present study, we evaluated the relationship between the chronologic CV-A16 epidemics in a restricted area, i.e., Fukushima Prefecture, Japan, and the genetic diversity of the CV-A16 strains. We also examined the geographic genetic relationship between the CV-A16 strains isolated in Fukushima and those isolated in other areas of Japan and China, using phylogenetic analyses constructed using the neighborjoining method on the basis of the VP4 and VP1 sequences. MATERIALS AND METHODSVirus strains. Pharyngeal swab samples were collected from patients with HFMD in the Fukushima Prefecture for virus surveillance and transferred to the Fukushima Institute for Public Health for virus isolation. HEp-2, Vero, and RD-18 cells were used for the isolation of enteroviruses. Confluent cell cultures were seeded in microplate wells and inoculated with 100 l of maintenance medium and 50 l of pharyngeal swab samples. The cell cultures were then incubated at 34°C in 5% CO 2 -95% air and observed for 7 days to check for cytopathic effects. A blind passage was performed once if no cytopathic effect was observed by the end of the observation period. Virus isolates were identified by a neutralization test using anti-CV-A16 polyclonal antibodies provided from the National Institute of Infectious Diseases in Japan. A total of 322 CV-A16 strains were isolated and identified from 1983 to 2003. Those isolates were stored at Ϫ80°C.PCR and sequence determination of VP4 gene. Randomly selected isolates (63 of 241 strains) from 1983 to 1999 and all isolates (69 strains) from 2000 to 2003 were used for further genetic analysis. A total of 132 strains were isolated from patients with HFMD.

Genetic characteristics of coxsackievirus A16 associated with hand, foot, and mouth disease in Nanjing, China

“…It is typically characterized by a mild fever followed by small red spots and bumps that may blister on the skin of palms, soles, in the oral cavity, and occasionally on the buttocks or/and genitalia [2]. For decades, multiple outbreaks of HFMD have occurred in many different countries, and CVA16 has played a critical role in the epidemic [2][3][4][5]. In recent years, the morbidity of HFMD has increased significantly in Asian countries including China, Japan, Malaysia, Thailand, and Korea, causing a huge burden for human health and economy [3,4,6].…”

Molecular Evidence of Persistent Epidemic and Evolution of Subgenotype B1 Coxsackievirus A16-Associated Hand, Foot, and Mouth Disease in China

“…In contrast, little interest was paid to CVA16 strains because CVA16-associated HFMD was usually mild and benign (2, 12). Although CVA16 is genetically most closely related to HEV71, the genetic diversity and molecular evolution of CVA16, unlike those of HEV71, have not been fully described (5,7,12,13). Cocirculation of CVA16 and HEV71 has been proven to have contributed to the serious outbreaks of HFMD that have occurred in China since 2007 (17); therefore, the genetic variability and the evolution of CVA16 were determined in this study.…”

A Neonatal Mouse Model of Coxsackievirus A16 for Vaccine Evaluation

“…These data demonstrated that anti-CA16 antibody may block virus invasion and protect mice against lethal challenge, and that the neonatal mouse model was a viable tool for evaluating vaccine efficacy. C oxsackievirus A16 (CA16) belongs to the Enterovirus genus of the Picornaviridae family and is one of the major pathogens associated with human hand, foot, and mouth disease (HFMD) (4,16,19). CA16 was first isolated in 1951 (43).…”