Genetic Characteristics of the Coxsackievirus A24 Variant Causing Outbreaks of Acute Hemorrhagic Conjunctivitis in Jiangsu, China, 2010

Abstract

During September 2010, an outbreak of acute hemorrhagic conjunctivitis reemerged in Jiangsu, three years after the nationwide epidemic in China in 2007. In total, 2409 cases were reported, 2118 of which were reported in September; 79.8% of those affected were students or teachers, with a median age of 16 years. To identify and demonstrate the genetic characteristics of the etiological agent, 52 conjunctival swabs were randomly collected from four different cities. After detection and isolation, 43 patients were positive for coxsackievirus A24 variant according to PCR and 20 according to culture isolation. Neither adenovirus nor EV70 was detected. A phylogenetic study of the complete 3Cpro and VP1 regions showed that the Jiangsu isolates clustered into a new lineage, GIV-C5, with two uniform amino-acid mutations that distinguished them from all previous strains. Another new cluster, GIV-C4, formed by Indian isolates from 2007 and Brazilian isolates from 2009, was also identified in this study. Interestingly, our isolates shared greatest homology with the GIV-C4 strains, not with the isolates that were responsible for the nationwide acute hemorrhagic conjunctivitis epidemic in China in 2007. Although all our isolates were closely related, they could be differentiated into two subclusters within GIV-C5. In conclusion, our study suggests that a new cluster of coxsackievirus A24 variant that had already evolved into diverse strains was associated with the acute hemorrhagic conjunctivitis outbreaks in Jiangsu in September 2010. These viruses might have originated from the virus isolated in India in 2007, rather than from the epidemic strains isolated in China in 2007.

A major outbreak of conjunctivitis caused by coxsackievirus A24, Réunion, January to April 2015

“…CV-A24v belonging to genotype IV was identified in all the samples by sequencing of the VP1 coding region (Figure 4). The 10 VP1 partial nt sequences shared a 99.1 to 100% nt identity and had 95.1 to 97.9% nt similarity with sequences from genotype IV isolates previously identified in AHC outbreaks in Egypt (2010) [21], Japan (2011) [22], China (2007 and 2010) [23][24][25], Brazil (2009) [26], India (2007) and Singapore (2005) [27] (Figure 4). They also grouped in a larger cluster containing the VP1 sequence from a genotype IV isolate detected in a traveller returning from Comoros to France in 2012 (Figure 4; accession number JX196594).…”

Molecular epidemiology of acute hemorrhagic conjunctivitis caused by coxsackie A type 24 variant in China, 2004–2014

“…CA24v has spread extremely rapidly in Asia, such as in Thailand, South Korea and Japan310131415. In 2002, the largest AHC outbreak due to CA24v was identified in South Korea with over one million cases12.…”

“…In 2002, the largest AHC outbreak due to CA24v was identified in South Korea with over one million cases12. The first outbreak of AHC in China was reported in Hong Kong in 1971, and a nationwide AHC epidemic caused by CA24v was reported in 20071316 with a total of 74,263 AHC cases. From 2007 to 2010, additional CA24v-associated AHC outbreaks were reported in Yunnan, Guangdong and Jiangsu Provinces as well as in Taiwan413171819.…”

“…The first outbreak of AHC in China was reported in Hong Kong in 1971, and a nationwide AHC epidemic caused by CA24v was reported in 20071316 with a total of 74,263 AHC cases. From 2007 to 2010, additional CA24v-associated AHC outbreaks were reported in Yunnan, Guangdong and Jiangsu Provinces as well as in Taiwan413171819. AHC could affect 50% of the population in communities within one or two months due to super human-to-human transmission71120.…”

“…AHC belongs to the Class C notifiable infectious disease category in China. AHC cases diagnosed by physicians should be registered through the public health surveillance program within 24 hours of a diagnosis1319. For this study, the notifiable surveillance data from 2004 to 2014 in China was used to analyze the molecular epidemiological features in the largest sample size with the aims to identify the specificities of the high-risk areas, populations and seasons and the clinical severity as well as to identify the etiological agent that caused the outbreaks.…”