Epidemiological characteristics and influencing factors of adenovirus-associated acute conjunctivitis in Shenzhen，2014‒2022 / 上海预防医学

ObjectiveTo investigate the epidemic characteristics and influencing factors of acute conjunctivitis caused by human adenovirus（HAdv）in Yantian District of Shenzhen City， Guangdong Province from 2014 to 2022， and to provide evidence for formulating effective prevention and control measures. MethodsDescriptive epidemiology was used to analyze the epidemiological characteristics of acute hemorrhagic conjunctivitis （AHC） cases reported from the Chinese disease prevention and control information system. Etiological characteristics of laboratory-confirmed cases were analyzed， and a case-control study method of test-negative design （TND） was conducted as well. According to the result of HAdv detection， analysis was used to identify the influencing factors of morbidity. ResultsA total of 1 005 AHC cases were reported in Yantian District， Shenzhen City from 2014 to 2022， with an average annual incidence rate of 49.49/105. The incidence rate ranged from 4.67/105 to 117.28/105. The peak incidence occurred from July to October each year， with a male-to-female ratio of 1.42∶1. The median （P25，P75） age of onset was 29（12，40） years. A total of 716 eye swabs were collected for etiological detection from 2014 to 2022. HAdv positive detection rate was 36.45% （263/716）， Cox 24v positive detection rate was 0.28% （2/716）， while EV70 was not detected. The longest viral shedding time in eye swabs was 10 days， with a median of 2 days. The highest HAdv positive detection rate （47.47%） was observed when the sampling-to-onset interval was 4‒5 days， and the difference was statistically significant （P<0.05）， with a trend of first increasing and then decreasing. Multivariate logistic regressing analysis showed that aged 18‒ years， and average temperature higher than 24.90 ℃ 3 days before onset （P<0.05） were the risk factors for acute HAdv conjunctivitis. ConclusionAHC in Yantian District， Shenzhen City showed a low level of prevalence from 2014 to 2022， with HAdv being the predominant pathogen. The peak period of viral shedding occurred on the 4th to 5th day after symptom onset， suggesting the importance of adherence to strict home isolation for infected persons. Aged18‒ years and average temperature increased 3 days before onset are associated with an increased risk of adenoviral conjunctivitis. It is recommended to strengthen personal protection and keep doing a good job of AHC surveillance and early warning， so as to timely prevent the outbreaks of AHC.

Identification and complete genome sequencing of human adenovirus type 55 isolated from a patient with acute hemorrhagic conjunctivitis / 上海预防医学

ObjectiveTo determine the genomic characteristics of a subgenus B human adenovirus strain isolated in Shanghai in 2021. MethodsAn adenovirus type 55 strain was isolated and identified from a patient with acute hemorrhagic conjunctivitis （AHC）. Complete genome of the strain was obtained using the next-generation sequencing （NGS）. Phylogenetic trees were reconstructed based on the sequences of Hexon， Fiber， Penton and complete genome to genomically characterize this strain. ResultsPhylogenetic analysis based on the complete genome classified this strain （MH2021001） into subgenus B， subspecies B2 of HAdV-55. Hexon gene of MH2021001 had close phylogenetic relationship with HAdV-11， while Fiber and Penton genes had close relationship with HAdV-14. The MH2021001 showed high nucleotide identity with currently prevalent HAdV⁃55 strains （>99.90%）. The complete genome had 99.96% nucleotide identity to the 73-GD_CHN_2016 strain isolated in Guangdong. In addition， the amino acid sequence of MH2021001 had several substitutions in regions coding for E1B， L4， E3 and L5. ConclusionThis strain has been classified to HAdV-B55. No recombination event is identified in the complete genome. Due to multiple amino acid substitutions， the biological characteristics of the strain need to be further identified.

Study on the complete sequence of CA24 variant isolated during the acute hemorrhagic conjunctivitis outbreaks in Zhejiang province during 2002 to 2010 / 中华流行病学杂志

Objective To analyze the genetic characteristics of the complete sequence of coxsackievirus A24 variant(CA24v) isolated from acute hemorrhagic conjunctivitis (AHC) outbreaks in Zhejiang province during 2002 to 2010.Methods Complete sequences of CA24v epidemic strains isolated in different years were amplified under the RT-PCR assay,while the sequences of whole genome,VP1,and 3C region of Zhejiang strains were compared with epidemic strains isolated in other areas of China and abroad.Results The whole genome of Zhejiang CA24v strains isolated in 2002 and 2010 was 7456-7458 bp in length,encoding a polyglutamine protein which containing 2214 amino acid residues.There was a insertion with T on site 97 and 119 within 5' non-coding region between epidemic strain Zhejiang/08/10 and strains isolated in 2002.The rates of amino acid homology among Zhejiang/08/10 and other strains isolated since 2002 were between 94.7％ and 100.0％.Compared with the representative strains circulated within the recent 60 years,the largest average amino acid variations had been occurred on region 2A and 3A,with the ratios as 8.4％ and 7.3％ respectively.The smallest variation happened in region 3D,with the ratio only as 1.9％.The rates of stable amino acid variation on the whole genome between strains isolated since 1987 and 2002 were 38 and 20.P-distance within groups appeared that region 3C was more stable than VP1 of strains isolated in 2002-2010,and the 3D of early strain Jamaica/10628/87 might have had a nature of recombination but not observed on those epidemic strains in recent years.Conclusion Within the evolution of CA24v strains,the time course was more significant than the geographical differences.There had been sporadic epidemics of AHC caused by CA24v in Zhejiang province since 2002.

Study on the efficacy of quarantine during outbreaks of acute hemorrhagic conjunctivitis outbreaks at schools through the susceptive-infective-quarantine-removal model / 中华流行病学杂志

To assess the efficacy of quarantine for acute hemorrhagic conjunctivitis (AHC)outbreaks control in schools,by using the Compartment Model.Through combining the characteristics of both AHC and compartment model,we built a susceptive-infective-removal (SIR) model suited for AHC outbreaks control in schools,and then quarantine was added into the model to develop a susceptive-infective-quarantine-removal (SIQR) model.An outbreak of AHC in Changsha in 2011 was employed as a sample to assess the effect of quarantine for the prevention and control of AHC.Basic reproduction number (λ 0) of the AHC outbreak without intervention was 6.80,thus the transmission speed of the disease became quite fast.If no intervention had been adopted,almost all the students,faculties and staff members would have been infected within 23 days,and the accumulative cases would become 738,with the total attack rate (TAR) as 99.73％.The peak of the outbreak was at Sep.11th and the number of new cases was 126 on that day.The efficacy would have been different if quarantine forces had been taken at different time and differently.The bigger and earlier the quarantine force had been adopted,the lower morbidity peak and the smaller TAR would have been appeared,with better efficacy of outbreak control.If the quarantine rate had been taken at the level of 90％ on the sixth day,the accumulative case would have been reduced to 132 and the TAR had become 17.84％ consequently.Quarantine program could be used as a main intervention approach to be employed for ACH outbreak at schools.

Application of Susceptible-Infected-Recovered model in dealing with an outbreak of acute hemorrhagic conjunctivitis on one school campus / 中华流行病学杂志

To simulate intervention measures in controlling an outbreak of acute hemorrhagic conjunctivitis on one school campus by using the Susceptible-Infected-Recovered (SIR) model, to provide evidence for preparedness and response to the epidemic. Classical SIR model was used to model the epidemic. Malthusian exponential decline method was employed to estimate the infective coefficient β for interventions. The initial value of parameters was determined based on empirical data. The modeling was implemented using Matlab 7.1 software. Without interventions, the outbreak was expected to experience three phrases: (1)early stage (the first 5 days) in which the epidemic developed slowly and could be intervened easily; (2) rapid growing stage (6-15 days) in which the number of infected cases increased quickly and the epidemic could not be well controlled;and (3) medium and late stage (16 days and later) in which more than 90% of the susceptible persons were infected but the intervention measures failed to prevent the epidemic. With the implementation of interventions, the epidemic was predicted to be controlled in the early stage, under the SIR model. The simulation based on the SIR model kept an acceptable consistency with the actual development of epidemic after the implementation of intervention measures. The SIR model seemed effective in modeling interventions to the epidemic of acute hemorrhagic conjunctivitis in the schools.

Detection and Phylogenetic Analysis of Coxsackievirus A24 Variant Causing Nation-wide Epidemic of Acute Hemorrhagic Conjunctivitis in Korea, 2002 / 감염과화학요법

BACKGROUND: Nation-wide outbreak of acute hemorrhagic conjunctivitis occurred in the summer, 2002 in South Korea. We identified the causative agent of this outbreak through virus culture and molecular biological techniques. METHODS: Polymerase chain reaction (PCR) was carried out with direct conjunctival swab samples and cell culture supernatants. Conjunctival swab was done at a community based-eye clinic in Seoul, September 2002. Initial screening for adenovirus and enterovirus was performed. Nested PCR for adenovirus was done with adenovirus common primers using direct swab sample, and reverse transcription PCR (RT-PCR) for enterovirus was done with enterovirus common primers. RT-PCR with primer 188/222 for VP1 region of enterovirus was done, if initial screening test was positive. PCR product was sequenced, and homology searching, compared to prototype strains, was done for serotyping. Protease 3C region of coxsackievirus A24v was amplified and sequenced with primer D1/U2. The sequence of this region was compared to those of viral isolates, which had been obtained from several Asian outbreaks since 1970. RESULTS: Conjunctival swabs were performed in 88 patients. Thirty nine (44%) samples out of the 88 were culture positive on HeLa or MRC-5 cells. Nine (100%) out of 9 culture supernatants, randomly selected from 39 culture positve samples, were positive for coxsackievirus A24v-specific RT-PCR. Phylogenetic analysis showed that sequences from 14 culture positive supernatants, randomly selected from 39 culture positive samples, clustered into a time-related, but distinct lineage, with Asian strains. CONCLUSIONS: We identified the causative agent of the epidemic hemorrhagic conjunctivits in year 2002 as coxsackievirus A24v.

Detection and Phylogenetic Analysis of Coxsackievirus A24 Variant Causing Nation-wide Epidemic of Acute Hemorrhagic Conjunctivitis in Korea, 2002 / 감염과화학요법

BACKGROUND: Nation-wide outbreak of acute hemorrhagic conjunctivitis occurred in the summer, 2002 in South Korea. We identified the causative agent of this outbreak through virus culture and molecular biological techniques. METHODS: Polymerase chain reaction (PCR) was carried out with direct conjunctival swab samples and cell culture supernatants. Conjunctival swab was done at a community based-eye clinic in Seoul, September 2002. Initial screening for adenovirus and enterovirus was performed. Nested PCR for adenovirus was done with adenovirus common primers using direct swab sample, and reverse transcription PCR (RT-PCR) for enterovirus was done with enterovirus common primers. RT-PCR with primer 188/222 for VP1 region of enterovirus was done, if initial screening test was positive. PCR product was sequenced, and homology searching, compared to prototype strains, was done for serotyping. Protease 3C region of coxsackievirus A24v was amplified and sequenced with primer D1/U2. The sequence of this region was compared to those of viral isolates, which had been obtained from several Asian outbreaks since 1970. RESULTS: Conjunctival swabs were performed in 88 patients. Thirty nine (44%) samples out of the 88 were culture positive on HeLa or MRC-5 cells. Nine (100%) out of 9 culture supernatants, randomly selected from 39 culture positve samples, were positive for coxsackievirus A24v-specific RT-PCR. Phylogenetic analysis showed that sequences from 14 culture positive supernatants, randomly selected from 39 culture positive samples, clustered into a time-related, but distinct lineage, with Asian strains. CONCLUSIONS: We identified the causative agent of the epidemic hemorrhagic conjunctivits in year 2002 as coxsackievirus A24v.

A Study for Viral Identification of Acute Viral Conjunctivitis

Acute viral conjunctivitis was known as an infectious disease affected by various viruses and characterized seasonal variation, prevalent especially in summer. In Korea, the clinic loepidemiologic study of AVC was not conclusive. Therefore, further research should be conducted to improve the primary health care and the application of diffrential diagnosis and its therapy. Clinical symptoms and signs of 131 patients who was confirmed viral conjunctivitis among 237 patients was evaluated at the Chung-Ang University Hospital in 1987, 1989 and 1990. Along with physical examination, specimens from the conjunctival swab were cultured and isolated, and a sereologic test-Neutralizing test for enterovirus 70, and complement fixation test for adenovirus-was performed. As a result, acute hemorrhagic conjunctivitis was relatively epidemic in 1987 and 1990 (67.7 and 47.1 %), and epidemic keratoconjunctivitis in 1989 (91.8%).

Preparation and identification of monoclonal antibodies against cell receptors of acute hemorrhagic conjunctivitis viruses / 中国免疫学杂志

To prepare monoclonal antibodies for blocking acute hemorrhagic conjunctivitis (AHC)viruses,BALB/C mice were immunized with Hela cells.The spleen of immunemouse was re-moved,and spleen cells were fused with SP2/0 cells.The antibodies against cell receptors wereselected by cell protection assay.Four cell strains secreted McAbs designated R7.R8.R16 andR24 were screened to be able to block cellular receptors and inhibit the infection of Ev70 as wellas CA24v on Hela cell.These results demonstrate that the receptors for Ev70 and CA24v are si-miliar.Indirect immunofluorescence test with the four McAbs showed definite fluorescence onliving Hela cells,which the intensity was concordance with the mean intensity resulted fromflowcytometer.Positive reaction on fixed Hela cells were only observed with R7 and R8.