Emergency vector control in a DENV-2 outbreak in 2002 in Pingtung City, Pingtung County, Taiwan.

This paper reports the strategy and effectiveness of an emergency control program conducted in Pingtung City, Taiwan in response to dengue outbreaks. In our control strategy, we carried out 3 insecticide space sprays with an interval of 6-7 days and 2 source reductions to cover the entire duration of dengue virus exposure in humans and mosquito vectors. The control effect was demonstrated by a significant reduction in the Breteau (51.1%) and larval (80.0%) indices, but no such effect was demonstrated by alterations in the adult index (54.9%), house index (45.0%), container index (33.8%), or by indoor (15.8%), outdoor (31.2%), or total water-filled containers (22.7%) per 100 premises examined. The contribution made by the reduction in the number of positive containers was primarily in the outdoor (77.2%), and not the indoor containers (-6.0%). This reduction attributed to an overall reduction of 96.0% Aedes albopictus larvae and 71.0% Aedes aegypti. Therefore, 4 weeks after this extensive emergency control measure, the number of dengue cases dropped to one. Finally, due to both the decrease in temperature resulting from the upcoming winter, and to the sustained effort toward source reduction, the transmission cycle of DENV-2 in Pingtung City was interrupted at the beginning of 2003, and no additional cases were identified in late 2003.

Application of the dengue virus NS1 antigen rapid test for on-site detection of imported dengue cases at airports.

We used the dengue virus NS1 antigen (Ag) rapid test for on-site detection of imported dengue cases at airports. Among 22 positive cases of dengue identified from 850 patients with a fever suspected to have dengue, 17 were NS1 Ag test positive. These findings demonstrate the usefulness of the NS1 Ag rapid test in screening imported dengue cases at airports.

The changing epidemiology of prevalent diagnosed HIV infections in Taiwan, 1984-2005.

By the end of 2005, there were 10,158 reported cases of HIV infections in Taiwan, of them, 2,403 had developed full blown AIDS, and 1,333 had died. It represented an average annual increase of 15% in HIV diagnoses before 2003. The most common route of transmission is through men having sex with men followed by heterosexual contact, while infections through injecting drug use (IDUs) remained low. However, the number of newly reported HIV infections has been rising sharply since 2003, mainly among IDUs. The consequences of this HIV/IDU epidemic include a rapid increase in female HIV/AIDS patients and a decreased mean age of HIV/AIDS cases. Only 2% of patients in the IDU group have been diagnosed with AIDS, suggesting that most IDU cases are in the early stage of HIV infections. HIV/AIDS patients are provided with free medical care by the government in Taiwan, including anti-retroviral treatment. The case fatality rate of AIDS cases declined gradually from 64% in 1996 to 8.9% in 2005. Patients in the IDU group seek medical care less frequently than patients in the sexual contact group. Statistics show that 61.4% of patients in the IDU group did not seek HIV-related medical care, significantly higher compared to the sexual contact group. The Taiwanese government implemented a trial "Harm Reduction Programme," which involved a needle-syringe programme (NSP) and substitution treatment, in August 2005. After 1 year's pilot study, the HIV incidence in cities with NSP decreased from 13.9 to 13.3 per 100,000 persons compared to an incidence increase from 11.5 to 15.3 per 100,000 persons in cities without NSP. We scaled up the programme to cover the whole of Taiwan in July 2006 and are expecting to see the efficacy in the near future.

Serologic and molecular biologic methods for SARS-associated coronavirus infection, Taiwan.

Severe acute respiratory syndrome (SARS) has raised a global alert since March 2003. After its causative agent, SARS-associated coronavirus (SARS-CoV), was confirmed, laboratory methods, including virus isolation, reverse transcriptase-polymerase chain reaction (RT-PCR), and serologic methods, have been quickly developed. In this study, we evaluated four serologic tests ( neutralization test, enzyme-linked immunosorbent assay [ELISA], immunofluorescent assay [IFA], and immunochromatographic test [ICT]) for detecting antibodies to SARS-CoV in sera of 537 probable SARS case-patients with correlation to the RT-PCR. With the neutralization test as a reference method, the sensitivity, specificity, positive predictive value, and negative predictive value were 98.2%, 98.7%, 98.7%, and 98.4% for ELISA; 99.1%, 87.8%, 88.1% and 99.1% for IFA; 33.6%, 98.2%, 95.7%, and 56.1% for ICT, respectively. We also compared the recombinant-based western blot with the whole virus-based IFA and ELISA; the data showed a high correlation between these methods, with an overall agreement of >90%. Our results provide a systematic analysis of serologic and molecular methods for evaluating SARS-CoV infection.