| Objective: To understand the epidemic and pathogenic characteristics of onychomadesis linked to hand,foot and mouth disease(HFMD) in the surveillance area of Hebei Province, in order to provide scientific evidence for surveillance、prevention and control of onychomadesis,and to accumulate materials of complications linked to HFMD.Methods:1 According to the incidence of HFMD over the years in Hebei province from national supervision paogram of HFMD, five monitoring sites were established including Zhangjiakou, Chengde, Baoding, Shijiazhuang and Xingtai which were elected by simple random sampling.2 The laboratory-confirmed cases with HFMD in Shijiazhuang, Baoding and Chengde during the first haft year of 2013 were pre-investigated the survey scheme was then adjusted based on the results, then the laboratory-confirmed cases with HFMD in the five monitoring sites from January to September of 2014 were entrolled in a retrospective investigation about onychomadesis.3 The specimens of cases with onychomadesis linked to HFMD were rechecked by Real time PCR and isolated with RD cells. The positive specimens of other enterovirus were detected if they were Cox A6 or Cox A10.4 The VP1 of all positive strains were amplificated by RT-PCR with specific primer pairs for VP1 entire gene sequences, and the PCR products were sequenced to perform nucleotide homology and construct the phylogenetic trees for analyzing the genovariation of strains with onychomadesis linked to HFMD.5 All the data was analyzed by Statistical software of SPSS13.0.Results:1 In the pre-survey, all the 295 patients with HFMD were successfully followed up, and the response rate was 100%.While in this survey, all of the 1446 HFMD cases(100%) were successfully followed.2 1586 of the 1741 cases with HFMD( 91.1%) were under five years old. 142( 8.2%) and 13(0.7%) cases respectively came from five to ten years old and more than ten years old. 1085 cases were male and other were female, so the ratio between male and female was 1.65:1. The occupation distribution was 1364 cases of scattered children, 327 cases of childcare children, 46 cases of students and 4 cases of others.The result of area distribution was 691 cases in Shijiazhuang,352 in Baoding,351 in Chengde,282 in Xingtai and 38 in Zhangjiakou.3 45 of the 1741 HFMD cases had been attack by onychomadesis with a rate of 2.6%. All of them were excluded any injury and other diseases. And there was no onychomadesis patients in their families. 26 of the 45 cases with onychomadesis were male and others were female, so the ratio between male and female was 1.37:1. Besides a 35-year-old patient, the average age of others was 1.75±1.31 years old(rang from 0 to 6 years old). 75.6 percent was 0 to 3 years old. The occupation distribution was 37 cases of scattered children, 6 cases of childcare children, 1 student and 1 adult. The result of area distribution was 25 cases in Shijiazhuang, 10 in Chengde,9 in Baoding and1 in Zhangjiakou.The attack rates of onychomadesis in Shijiazhhuang, Chengde, Baoding,Zhangjiakouand Xingtai were respectively 3.6%,2.8%,2.6%,2.6%and 0%. The attack rates of Shijiazhuang and Chengde were hinger than Xingtai.4 Time intervals of 45 cases between onychomadesis and HFMD were-10 to 86 days(average of 29.62±16.37 days).1 case onychomadesised before HFMD 10 days, 1 case before 3 days,3 cases were after HFMD 0 to 10 days,7 cases were 10 to 20 days, 11 cases were 20 to 30 days, 11 cases were 30 to 40 days,8 cases were 40 to 50 days and 3 cases were 50 to 86 days.The number of shed nails was 1 to 43, and the average number was 3.07 per case. The number of fingernails falling out was 26, and toenails’ was 8. Both fingernails and toenails shed in the rest. A significant difference was found between fingernails and toenails.All of 45 cases were mild. 41 of the 45 cases had fever, 45 cases had rash and 32 patients were with stomatitis. In terms of the respiratory system, 8 cases had sore throat, 3 cases had a cough, 2 cases had a runny nose, and 2 patients had both sore throat and runny nose.5 800 of the 1696 cases without onychomadesis were HEV71 positive, 388 were Cox A16 and 508 were other enterovirus. While 43 of 45 cases with onychomadesis were other enterovirus positive which included 41 Cox A6 and 2 ECHO30, 1 was HEV71 and 1was Cox A16.6 The VP1 of all positive strains, which included 1 HEV71 strain, 1 Cox A16 strain, 2 Cox A6 strains and 2 ECHO strains, were amplificated by RT-PCR, and the PCR products were sequenced to perform nucleotide homology. The results showed that the nucleotide homology of HEV71 onychomadesis strain and 4 strains with HFMD was 94.6%~96.2%. Its nucleotide constitution was similar with strains of C4 a subtype. The nucleotide homology of Cox A16 strain HBTJ14001 and 4 strains with HFMD was 91.5%~99.2%. Its nucleotide constitution was similar with strains of B1 b subtype. The nucleotide homology of Cox A6 strains and 4 strains with HFMD was 94.5%~98.8%. Its nucleotide constitution was similar with strains of China in recent years and onychomadesis in Finland, the nucleotide homology were respectively 94.6%~98.7% and 92.7%~98.6%. The nucleotide homology of ECHO30 strains was 99.1%. Its nucleotide constitution was similar with strains of G subtype.7 The phylogenetic trees were constructed by DNASTAR package. The phylogenetic tree of HEV71 VP1 displayed that these 5 strains were in the same clade, which belonged to C4 a genotype. They and prototype of HEV71 had farther genetic relationship. The phylogenetic tree of Cox A16 VP1 showed that these 5 strains were in the same clade, which belonged to B1 b genotype. They and prototype of Cox A16 had farther genetic relationship. The strains isolated from Cox A6 in this study had farther genetic relationship with prototype of Cox A6 and the strains isolated in Shandong before 1996, but they had closer relationship with the strains isolated in China in recent years. The phylogenetic tree of ECHO30 VP1 displayed that HBTJS010 and HBTJS055 were in the same clade, which belonged to G genotype. They and the strains isolated in China before 2008 had farther genetic relationship, but closer with the strains isolated in China over the years.Conclusions:1 Onychomadesis foolowing HFMD 20 to 40 days later exsited in Hebei province, but its attack rate is low and nails’ attack rate is higher than toenails’.2 Onychomadesis linked to HFMD is more common among the scattered children, but adults can also suffer from onychomadesis.The clinical symptom of the patients is mild when they are ill with HFMD, and vesicular lesions may be seen in special positions.3 HEV71 is the main pathogen of HFMD in the monitoring sites of Hebei province.While Cox A6 is the primary pathogen of onychomadesis linked to HFMD.4 There is no significant genovariation in VP1 gene sequences between the strains of onychomadesis and HFMD. All of them belong to the same subtype with the strains across China in recent years. |
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