Sentinel Surveillance for Enterovirus 71, Taiwan, 1998.

Dispatches

Outbreaks of enterovirus 71 have been reported around the world since 1969. [ILLEGIBLE TEXT] most recent outbreak occurred in Taiwan during April-July 1998. This hand, foot, mouth disease epidemic was detected by a sentinel surveillance system in April a beginning of the outbreak, and the public was alerted.

Enterovirus type 71 (EV71), one of the etiologic agents of epidemic hand, foot, a disease (HFMD), has been associated with febrile rash illness, aseptic meningitis encephalitis, and a syndrome of acute flaccid paralysis similar to that caused by [ILLEGIBLE TEXT] (1,2). EV71 was identified in 1969 in the United States, when it was isolated [ILLEGIBLE TEXT] of an infant with encephalitis in California. By 1998, many EV71 outbreaks had reported around the world. In addition to the outbreak in California in which one reported, four other outbreaks resulted in many fatal cases involving clinical [ILLEGIBLE TEXT] death in young children (Bulgaria, May-September 1975; Hungary, 1978; Malay June 1997; Taiwan, April-August 1998) (3-5). To the best of our knowledge, the Taiwan marked the first time that an EV71 outbreak was detected by a surveillan [ILLEGIBLE TEXT] which alerted the public about the epidemic of HFMD. We describe how the EV was reported by a sentinel surveillance system established in July 1989 by [ILLEGIBLE TEXT] Surveillance and Quarantine Service (originally National Quarantine Services), Health, Taiwan.

In this sentinel surveillance system, public health officers contact local and [ILLEGIBLE TEXT] physicians weekly to actively collect disease information. On the basis of inform respiratory infection are among the diseases subject to routine surveillance. For [ILLEGIBLE TEXT] we have established two channels of data collection: telephone interviews and [ILLEGIBLE TEXT] mailed by physicians. Approximately 850 physicians (fewer than one tenth of [ILLEGIBLE TEXT] from every county in Taiwan participate in the system: 258 in the northern [ILLEGIBLE TEXT] central region, 296 in the southern region, and 85 in the eastern region (Table); are pediatricians, general practitioners, and family physicians. Only a few are [ILLEGIBLE TEXT] throat specialits.

Table. Physician distribution, Sentinel Surveillance System, Taiwan

                         No. cards
Region of                mailed by    Total no.
Taiwan      Interviews   physicians   physicians

Northern       109          149          258
Central         27          184          211
Southern       175          121          296
Eastern         13           72           85
Total          324          526          850

When an epidemic of fatal myoca reported in Sarawak, Malaysia, in started to collect information [ILLEGIBLE TEXT] and vesicular pharyngitis [ILLEGIBLE TEXT] the sentinel surveillance system. March 1998, some physicians [ILLEGIBLE TEXT] notable increase of cases of [ILLEGIBLE TEXT] pharyngitis (herpangina), and [ILLEGIBLE TEXT] stomatitis exanthem. Furthermore, upsurge of HFMD was seen in [ILLEGIBLE TEXT] outpatient settings at the end of A (Figure 1).

[Figure 1 ILLUSTRATION OMITTED]

Surveillance data provided the [ILLEGIBLE TEXT] immediate public health action. [ILLEGIBLE TEXT] number of weekly reported cases increased twofold at the end of April, the [ILLEGIBLE TEXT] informed about the epidemic of HFMD and herpangina and the threat of [ILLEGIBLE TEXT] (May 12). Measures for preventing the spread of infection (e.g., practicing good times, confining infected children at home, avoiding contact with infected [ILLEGIBLE TEXT] advised. However, the number of reported cases still dramatically increased to [ILLEGIBLE TEXT] 3,000 in the following week. Although some errors in reporting might have [ILLEGIBLE TEXT] confident that the reporting quality was adequate. The sentinel physicians, who [ILLEGIBLE TEXT] voluntarily cooperated with us for 10 years, used a clinical case definition of HFMD/herpangina we created when the surveillance started.

Monitoring incidence of the fatal and most severe cases of HFMD appeared critical therefore, another report system, designed for [ILLEGIBLE TEXT] severe and fatal cases, was established (May 29) to enroll all well-defined severe and fatal [ILLEGIBLE TEXT] hospitals and medical centers. This new system established a network of various agencies, general and regional hospitals, and medical centers. The difference [ILLEGIBLE TEXT] systems was that, while the sentinel surveillance system was physician-based, [ILLEGIBLE TEXT] was hospital-based. Severe and fatal cases were defined as HFMD with [ILLEGIBLE TEXT] including aseptic meningitis, encephalitis, myocarditis, acute flaccid paralysis, [ILLEGIBLE TEXT] deteriorating clinical course, and death. Both surveillance systems worked [ILLEGIBLE TEXT] from June 1998 onward. We found that the trend peaked and declined earlier in [ILLEGIBLE TEXT] system than in the hospital-based surveillance system (Figure 1, 2).

[Figure 2 ILLUSTRATION OMITTED]

A case-control study was implemented, and enterovirus isolation data were [ILLEGIBLE TEXT] enterovirus isolations, from patients with severe and fatal cases, were in stool [ILLEGIBLE TEXT] throat secretions, cerebrospinal fluid, blood, and central nervous system tissue, [ILLEGIBLE TEXT] EV71, Coxsackie, and ECHO. Additional studies comparing rates of EV71 [ILLEGIBLE TEXT] different years are in progress and will be reported separately. Most isolated [ILLEGIBLE TEXT] EV71 from all specimens in this epidemic. The epidemiologic, clinical, and [ILLEGIBLE TEXT] evidence suggests an association between EV71 infection and this epidemic of [ILLEGIBLE TEXT] However, the causes of the severe cases and deaths in Taiwan are yet to be [ILLEGIBLE TEXT]

A physician-based sentinel surveillance system can play an important role in [ILLEGIBLE TEXT] emerging infectious diseases. Even though the data collected may be rough, a [ILLEGIBLE TEXT] surveillance system can provide necessary information for monitoring [ILLEGIBLE TEXT] diseases, guiding further investigation, and evaluating control measures, as well warning for epidemics and rationale for public health intervention. Early [ILLEGIBLE TEXT] communicable diseases and immediate public health intervention can curtail the illnesses and deaths and reduce negative effects on international travel and trade [ILLEGIBLE TEXT]

References

(1.) Melnick JL. Enterovirus type 71 infection: a varied clinical pattern [ILLEGIBLE TEXT] mimicking paralytic poliomyelitis. Rev Infect Dis 1984;6 Suppl:S387-90.

(2.) Alexander JP Jr, Baden L, Pallansch MA, Anderson LJ. Enterovirus 71 [ILLEGIBLE TEXT] neurologic disease--United States, 1977-1991. J Infect Dis 1994; 169:905-[ILLEGIBLE TEXT]

(3.) Shindarov LM, Chumakov MP, Voroshilova MK, Bojinov S, Vasilenko S I, et al. Epidemiological, clinical, and pathomorphological characteristics poliomyelitis-like disease caused by enterovirus 71. Journal of Hygiene, E Microbiology, and Immunology 1979;23:284-95.

(4.) Nagy G, Takatsy S, Kukan E, Mihaly I, Domok I. Virological diagnosis of type 71 infections: experiences gained during an epidemic of acute CNS [ILLEGIBLE TEXT] Hungary in 1978. Arch Virol 1982;71:217-27.

(5.) Centers for Disease Control and Prevenetion. Deaths among children [ILLEGIBLE TEXT] outbreak of hand, foot, and mouth disease--Taiwan, Republic of China, A [ILLEGIBLE TEXT] 1998. MMWR Morb Mortal Wkly Rep 1998;47:629-32.

(6.) Heymann DL, Rodier GR. Global surveillance of communicable diseases. Dis 1998;4:362-5.

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Emerging Infectious Diseases Journal National Center for Infectious Diseases Centers for Disease Control and Prevention

URL: http://www.cdc.gov/ncidod/eid/vol5no3/wu.htm

Trong-Neng Wu,(*) Su-Fen Tsai,(*) Shu-Fang Li,(*) Tsuey-Fong Lee,(*) Tzu-Mei Mei-Li Wang,(*) Kwo-Hsiung Hsu,([dagger]) and Chen-Yang Shen([double dagger])

(*) Disease Surveillance and Quarantine Service, Ministry of Health, Taiwan, [ILLEGIBLE TEXT] China; ([dagger]) Bureau of Communicable Disease Control, Ministry of Health, Taiwan, China; and ([double dagger]) Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, China

Dr. Wu is vice superintendent of Municipal Hsiao-Kang Hospital, Kaohsiung Medical [ILLEGIBLE TEXT] Republic of China. He is also a professor at both Kaohsiung Medical College, Kaosiung, Taiwan Medical College, Taichung, Taiwan.

Address for correspondence: Su-Fen Tsai, Division of Disease Surveillance, Disease [ILLEGIBLE TEXT] Quarantine Service, Ministry of Health, F6, No.6, Lin Shen S. Rd., Taipei, Taiwan, R.O.C.; fax: [phone]; e-mail: [e-mail].