Kow-Tong Chen

Epidemiologic Features of Hand-Foot-Mouth Disease and Herpangina Caused by Enterovirus 71 in Taiwan, 1998-2005

OBJECTIVE. In 1998, an epidemic of hand-foot-mouth disease/herpangina was caused by human enterovirus 71 infection in Taiwan. The underlying factors of widespread emergence of viral infection are unclear. The purpose of this study was to assess the epidemiology of hand-foot-mouth disease/herpangina in Taiwan between March 1998 and December 2005. METHODS. We analyzed data reported to surveillance systems at the Taiwan Center for Disease Control. Viral isolation was performed by 11 reference virus laboratories at medical centers as well as the Taiwan Center for Disease Control. RESULTS. During the 8-year study period, the reported incidence of mild cases of hand-foot-mouth disease/herpangina varied from 0.8 to 19.9 cases per sentinel physician per week, peaking in 1998. Seasonal variations in incidence were observed, with an incidence peak observed during the summer season. Annual incidence changed significantly from 1998 to 2005. Both age-specific incidence and fatality of severe hand-foot-mouth disease/herpangina decreased as age increased. Most (93%) cases occurred in children who were aged 4 years and younger. Inpatients had a higher rate of enterovirus 71 infection than outpatients. Among severe cases, the majority (80%) had pulmonary edema/hemorrhage and encephalitis. CONCLUSIONS. Hand-foot-mouth disease/herpangina is a common disease in Taiwan. Enterovirus 71 infection has emerged as an important public problem causing serious clinical illness and, potentially, death in young children. Vaccine development is recommended for prevention of enterovirus 71 infection in the future.

First report from the Asian Rotavirus Surveillance Network.

Rotavirus remains the most common cause of severe, dehydrating diarrhea among children worldwide. Several rotavirus vaccines are under development. Decisions about new vaccine introduction will require reliable data on disease impact. The Asian Rotavirus Surveillance Network, begun in 2000 to facilitate collection of these data, is a regional collaboration of 36 hospitals in nine countries or areas that conduct surveillance for rotavirus hospitalizations using a uniform World Health Organization protocol. We summarize the Networks organization and experience from August 2001 through July 2002. During this period, 45% of acute diarrheal hospitalizations among children 0–5 years were attributable to rotavirus, higher than previous estimates. Rotavirus was detected in all sites year-round. This network is a novel, regional approach to surveillance for vaccine-preventable diseases. Such a network should provide increased visibility and advocacy, enable more efficient data collection, facilitate training, and serve as the paradigm for rotavirus surveillance activities in other regions.

Diseases Caused by Enterovirus 71 Infection

The purpose of this review was to explore the epidemiology, pathogenesis, virology, and management of enterovirus 71 (EV71) infection. Published literature was surveyed by Medline using the keyword “EV71.” The reported incidence of cases of hand-foot-mouth disease/herpangina varied from year to year; seasonal variations in incidence were observed, with a peak in incidence during the summer season. Most cases of hand-foot-mouth disease/herpangina hospitalized for complications occurred in children less than 5 years old. The brainstem was the most likely major target of EV71 infection. Different enteroviruses cocirculate in the community annually. The emergence of the EV71 epidemic in the Asia Pacific region has been associated with the circulation of 5 genetic lineages (genotypes B3, B4, C1, C2, C4) that appear to be undergoing rapid evolutionary changes. The relationship between the gene structure of the EV71 virus and the factors that ensure its survival, ease of transmission, and evasion of immunity is still unclear. EV71 central nervous system involvement causes serious clinical illness, death, and long-term neurologic and psychiatric disorders in young children. EV71 infection has emerged as an important public health problem. Vaccine development is recommended for the prevention of EV71 infection in the future.

SARS in Healthcare Facilities, Toronto and Taiwan

The healthcare setting was important in the early spread of severe acute respiratory syndrome (SARS) in both Toronto and Taiwan. Healthcare workers, patients, and visitors were at increased risk for infection. Nonetheless, the ability of individual SARS patients to transmit disease was quite variable. Unrecognized SARS case-patients were a primary source of transmission and early detection and intervention were important to limit spread. Strict adherence to infection control precautions was essential in containing outbreaks. In addition, grouping patients into cohorts and limiting access to SARS patients minimized exposure opportunities. Given the difficulty in implementing several of these measures, controls were frequently adapted to the acuity of SARS care and level of transmission within facilities. Although these conclusions are based only on a retrospective analysis of events, applying the experiences of Toronto and Taiwan to SARS preparedness planning efforts will likely minimize future transmission within healthcare facilities.

Sentinel Hospital Surveillance for Rotavirus Diarrhea in Taiwan, 2001–2003

We examined the epidemiological profile of rotavirus infection among children hospitalized for diarrhea in Taiwan, to assess the burden of this disease. From 1 April 2001 through 31 March 2003, children <5 years old with gastroenteritis admitted to 4 sentinel hospitals were enrolled in a surveillance study and had stool specimens tested for the presence of rotavirus, enteric adenovirus, and the bacterial pathogens for which routine screening is performed. For 52% of patients, a recognized enteric pathogen was identified, including rotavirus (43% of patients), bacteria (11%), enteric adenovirus (2.5%), and a mixture of pathogens (3.9%). Rotavirus was detected year-round, but great month-to-month variability made it difficult to identify a distinct seasonal pattern. Rotavirus disease was most common among children 7-23 months old, but the rate of rotavirus detection varied little between the youngest and oldest age groups. The novel strain P[8]G9 was detected most commonly (37% of strains), followed by strains P[8]G1 (31%), P[4]G2 (10%), P[8]G3 (9.3%), and P[8]G4 (3.7%). Rotavirus infection is the most important cause of diarrhea among hospitalized children in Taiwan, and a rotavirus vaccination program for young children might significantly reduce this problem.

Outbreak of Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis Associated With Mebendazole and Metronidazole Use Among Filipino Laborers in Taiwan

OBJECTIVES This study sought to identify the risk factors associated with an outbreak of Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) among Filipino laborers in Taiwan. METHODS Forty-six SJS/TEN patients were matched to 92 controls according to month of arrival in Taiwan, sex, and age. RESULTS The odds ratio for development of SJS/TEN was 9.5 (95% confidence interval [CI] = 3.9, 23.9) among workers who had used both metronidazole and mebendazole sometime in the preceding 6 weeks. In addition, a gradient increase in the occurrence of SJS/TEN was found with an increasing level of exposure to metronidazole. CONCLUSIONS This outbreak highlights the risk of SJS/TEN resulting from the use of both metronidazole and mebendazole and the need for control measures.

Cost-effectiveness of childhood rotavirus vaccination in Taiwan

OBJECTIVE Rotavirus is the most common cause of severe diarrhea in children. Two rotavirus vaccines (RotaTeq and Rotarix) have been licensed in Taiwan. We have investigated whether routine infant immunization with either vaccine could be cost-effective in Taiwan. METHODS We modeled specific disease outcomes including hospitalization, emergency department visits, hospital outpatient visits, physician office visits, and death. Cost-effectiveness was analyzed from the perspectives of the health care system and society. A decision tree was used to estimate the disease burden and costs based on data from published and unpublished sources. RESULTS A routine rotavirus immunization program would prevent 146,470 (Rotarix) or 149,937 (RotaTeq) cases of rotavirus diarrhea per year, and would prevent 21,106 (Rotarix) and 23,057 (RotaTeq) serious cases (hospitalizations, emergency department visits, and death). At US

Rotavirus infection and the current status of rotavirus vaccines

80 per dose for the Rotarix vaccine, the program would cost US

SARS in Taiwan: an overview and lessons learned

32.7 million, provided an increasing cost offset of US

Childhood Tuberculosis: Epidemiology, Diagnosis, Treatment, and Vaccination

19.8 million to the health care system with