Wen-Loong Huang

The change of etiological agents and clinical signs of epidemic viral conjunctivitis over an 18-year period in southern Taiwan

BackgroundEpidemic viral conjunctivitis is a highly contagious eye disease that occurs worldwide and is caused mainly by adenoviruses and enteroviruses. An 18-year analysis of the changes of pathogens and clinical signs in a subtropical and densely populated island presents certain special features.MethodsWe retrospectively analyzed the clinical information and laboratory records of the conjunctivitis patients with positive conjunctival swabs from 1980 to 1997.ResultsThe positive rate of laboratory diagnosis of epidemic conjunctivitis was 50.0% (1,233/2,467). From 1980 to 1994, the predominant causative agent of adenoviral keratoconjunctivitis was adenovirus type 8 (Ad8), with six genotypes being evolved. Three of the new Ad8 genotypes each caused a new epidemic. After 1995 the predominant adenoviral pathogens shifted to Ad37 and Ad19, and no more Ad8 was isolated. Enterovirus type 70 (EV70) was isolated from four outbreaks of acute hemorrhagic conjunctivitis (AHC) from 1980 to 1984, but rarely in later years. Coxsackievirus A type 24 variant (CA24v), which first appeared in 1985, appeared later as the causes of four major epidemics of AHC from 1985 to 1994. The overall clinical symptoms of viral conjunctivitis were more severe in the 1990s than in the 1980s.ConclusionIn southern Taiwan, outbreaks of adenoviral keratoconjunctivitis caused by new genomic variants could be associated with the long-term endemic co-circulation of Ad8, Ad19, and Ad37, while epidemics of CA24v AHC were caused mainly by introduction of new viral strains from neighboring countries. The aggravation of host symptoms in the 1990s needs further investigation and close follow-up.

Epidemic Keratoconjunctivitis Caused by a New Genotype of Adenovirus Type 8 (Ad8)—A Chronological Review of Ad8 in Southern Taiwan

PURPOSE To understand the pathogenic evolution of viral keratoconjunctivitis in Kaohsiung, Taiwan, a retrospective molecular and clinical analysis was conducted. METHODS From January 1990 to December 1994, conjunctival swab samples from patients suspected of having viral conjunctivitis were collected for viral culture isolation, neutralization test (NT), and endonuclease cleavage analysis. Six restriction endonucleases, comprising HindIII, BamHI, SalI, SstI, SmaI, and PstI, were used for cleavage. Clinical examinations of patients were performed by two senior ophthalmologists. RESULTS Twenty-one cases of a new genotype of adenovirus (Ad) type 8, designated as Ad8H, were discovered in the 27 detected adenovirus cases. The Ad8H has a distinct cleavage pattern, especially by HindIII and SalI. The Ad8H keratoconjunctivitis induced more subconjunctival hemorrhage (33.3%), keratitis (33.3%), and lymphadenopathy (85.7%) than other genotypes of Ad8 previously isolated in Kaohsiung, Taiwan. CONCLUSION We have discovered a new genotype, Ad8H, which was prevalent as the main pathogen of the adenoviral keratoconjunctivitis in Kaohsiung, Taiwan from 1990 to 1994. Adenovirus type 8 is evolving into more genotypes with a trend towards more severe symptoms, including subconjunctival hemorrhage, keratitis, and lymphadenopathy.

A Molecular Study of Adenovirus Type 8 Isolated from Viral Conjunctivitis in the Kaohsiung Area during 1983-1984: A Chronological Comparison of Subtypes by Endonuclease Cleavage Analysis

From march 1983 to February 1984, 74 isolates of adenovirus type 8 (Ad-8) were recovered from the conjunctival swabs of 692 cases with viral conjunctivitis in the Kaohsiung area. Out of the 47 Ad-8 isolates, 18 were selected randomly for enzymatic cleavage analysis with six different kinds of endonucleases: Pst Ⅰ, Hind Ⅲ, BamHⅠ, SalⅠ,SstⅠand SmaⅠ. A subtype comparison was made between the current 18 Ad-8 isolates and the 27 Ad-8 isolates recovered during the period from 1980 to 1981 in Kaohsiung which were described in our previous study. While the subtype C was predominant in the 1980-1981 period, the subtype E was most prevalent in the 1983-1984 period. A new subtype was identified and designated as subtype G in the current series of Ad-8 isolates studied. The prototype strain of Ad-8 (Trim) was not isolated in Kaohsiung among the series of Ad-8 isolates recovered in 1980-1981 and 1983-1984. The large numbers of variants in subtypes of suggested that this virus had continued to evolve in the Kaohsiung area during these years.

Adenovirus Types 19 and 37 Isolated from Viral Conjunctivitis in the Kaohsiung Area during 1983-1984: Molecular Epidemiological Study by DNA Endonuclease Cleavage Analysis

Thirty two isolates of adenovirus type 19 and six of type 37 were recovered from the conjunctiva of 629 cases with viral conjunctivitis in the Kaohsiung area from March 1983to February 1984. Seventeen isolates of Ad 19 and five of Ad 37 were randomly chosen for DNA emzymatic cleavage analysis by eight different kinds of endonucleases: Pst I, Hind III, BamH I, Sal I, Sma I, Sst I, EcoR I, and Kpn I. The results were as follows: 1.Two subtypes of Ad 19 were found; 16 isolates were different from the Ad 19 prototype, but identical to the subtype Ad 19A. The other was a new subtype, that was designated as Ad 19B. 2.Five isolates of Ad 37 were divided into two groups; 4 isolates were identical to the Ad 37 prototype. The other was a new subtype, designated as Ad 37B. This differed from the subtype Ad 37A previously found in Japan and Taiwan. 3.It appeared that Ad 19A and Ad 37 prototype were predominant during the period of 1983-1984, in Kaohsiung.

A Rapid and Simple Method for Preparation of Adenovirus and for Restriction Endonuclease Cleavage Studies

1981年Suzuki等提出由腺病毒感染細胞抽取病毒DNA之簡單實用的方法。抽取物儘管有細胞DNA的存在，仍無礙於病毒限制酶分割圖譜之分析。因該法所需的時間較長(超過十小時)操作上較繁複，吾人乃將其加以改良，期能改善上述的困擾。改良法是將已感染病毒的細胞以1% SDS及proteinase K(50 mg/ml)處理，置65℃ 1至1.5小時或隔夜之後，以緩衝液飽和的石炭酸一氯仿一異戊醇(25：24：1)抽取DNA兩次，再以RNase(10 mg/ml)在65℃處理30-40分鐘，再抽一次DNA後以冷酒精將DNA沈澱下來，經真空乾燥後溶於緩衝液中即可用來進行分析。本文乃將下列三種方法加以比較。方法(一)：本文改良Suzuki等氏法之改良法。方法(二)：由純化的病毒抽取 DNA。方法(三)：Suzuki 等氏法。將三種方法抽得的DNA以HindⅢ限制酶與之作用後，經電泳分析，照相後比較其限制酶分割圖譜發現三種方法的結果都可作為圖譜之分析，但改良法的優點有四：(1)可省一半以上的工作時間(由十小時減為四小時)。(2)品質和Suzuki法一樣且兩者之產量是方法(二)的四倍以上。(3)RNase, proteinase K 等酵素的用量至少可節省一半。(4)操作上更簡單。因此本改良法適於大量檢體之分子流行病學研究。

Seroepidemiological Study of Coxsackievirus Type A24 Variant (Ca24v) in Taiwan

In October 1985 and June 1986, for the first time, Taiwan experienced two outbreaks of acute hemorrhagic conjunctivitis (AHC) caused by a variant of coxsackievirus A24 (CA24v). Sera of virologically and clinically confirmed cases were studied together with the pre- and post-epidemic serum samples by the microneutralization method (cut-off titer, 1:8). The serum samples included 16 cases of virologically confirmed AHC and 18 cases of clinically diagnosed AHC which were collected during the period of January to July, 1987 (i.e., 7 to 21 months after the epidemic). In the same period of time, 374 serum samples were randomly collected as a post-epidemic control group. Meanwhile, 206 serum samples, which were randomly collected in 1980, were studied as a pre-epidemic control group. The results showed that in terms of CA24v neutralizing antibody (NTAb) positivity, a significant difference was found between the pre- and post-epidemic random sample groups (5.3% vs. 28.1%, P < 0.001) while no significant differences among the virologically confirmed, the clinically diagnosed and the post-epidemic random sample groups were noticed (31.3% vs. 28.1%; 44.4% vs. 28.1%, P > 0.05). For comparison, the enterovirus 70 (EV70) NTAb of the samples was studied simultaneously. The results showed that the positive rate and geometric mean titer of CA24v NTAb were lower than those of EV70 even in the post-epidemic serum samples collected shortly after the CA24v epidemic.

Study on some biological and antigenic characteristics of CA24v isolates in Taiwan in 1985-1989.

In order to understand the relationship between the CA24v isolates which caused two epidemics of acute hemorrhagic conjunctivitis (AHC) in 1985-1986 and 1988-1989 in Taiwan, biological and antigenic characteristics were studied with four CA24v strains, L077/85, V116/86, 590/88 and 722/89, which were isolated during the epidemics. The prototype strain, EH24/70, was used for comparison. In terms of cross neutralization, kinetic neutralization, plaque assay and protein electrophoresis, no obvious differences were found between the isolates from the two epidemics though differences were found between these isolates and the prototype.

Quantitative Study of the Conus/Optic Disc Ratio among Myopes with a Planimeter

With special reference to myopia, this study examined the coni of 713 eyes of 357 students who were between the ages of 21 and 35 years. The surface ratio of conus to disc was calculated using a planimeter. Coni were observed in 27.2% of 22 hyperopic eyes, 29.5% of 61 emmetropics, and 84.8% of 630 myopics. Among myopic eyes, the incidence of conus formation and surface ratio of conus to disc increased as the myopic degree or the ocular axial length increased.

A molecular study of ocular herpes simplex infection in Kaohsiung, Taiwan. Part I: Cleavage pattern analysis.

In order to investigate the relationship between genotypes of herpes simplex virus (HSV) and its clinical pictures in herpes simplex virus keratoconjunctivitis (HSK), fifty nine strains of HSV isolates, collected in the Kaohsiung Medical College Hospital during January 1981 to July 1991, and F strain (ATCC VR-73), a standard HSV-1, were studied. The viruses were isolated from HSK patients. All 59 strains were identified as HSV-1 using immunofluorescence monoclonal antibody method. The HSV DNAs were extracted and digested by restriction enzymes, BamH I, Kpn I and Sal I, followed by electrophoresis, and photographing. Six kinds of DNA cleavage patterns were found in Taiwan. The majority were E subtype (56.4%) then A subtype (27.3%), D subtype (7.3%), F subtype (5.4%), G subtype (1.8%) and H subtype (1.8%). Subtypes B and C were not found in this study. The cleavage patterns of two recurrent cases belonged to E and A subtypes. The identical cleavage patterns of two bilateral infections all belonged to the E subtype.