Airport fever screening in Taiwan, July 2003–June 2004, identified 40 confirmed dengue cases. Results obtained by capture immunoglobulin (Ig) M and IgG enzyme-linked immunoassay, real time 1-step polymerase chain reaction, and virus isolation showed that 33 (82.5%) of 40 patients were viremic. Airport fever screening can thus quickly identify imported dengue cases.

We present the results of laboratory-based dengue surveillance in Taiwan for 2005. A phylogenetic study showed that multiple dengue epidemics were caused by three different imported dengue virus (DENV) strains. A strain of DENV-3 (genotype I) imported from the Philippines first appeared in the southern part of Kaohsiung City and later spread to Kaohsiung County from August to December, which resulted in 77 cases of dengue. Another strain of DENV-3 (genotype II) imported from Vietnam first appeared in the central part of Kaohsiung City and later spread to Kaohsiung County from September to December, which resulted in 35 cases of dengue. A strain of DENV-2 (American/Asian genotype) imported from Vietnam first appeared in Tainan City and later spread to Kaohsiung City/County from October to December, which resulted in 60 cases of dengue. This study provides molecular epidemiologic evidence that most dengue in Taiwan is caused by imported strains of the virus.

During the period of August 2002 and November 2004, an epidemiological investigation for Bartonella infection was conducted in small mammals in Taiwan. Using whole blood culture on chocolate agar plates, Bartonella species were successfully isolated from 41.3% of the 310 animals tested. The isolation rate of Bartonella species varied among different animal species, including 52.7% of the 169 Rattus norvegicus, 28.6% of the 126 Sucus murinus, 10% of the 10 Rattus rattus and 66.7% of the three Rattus losea. Bacteremia prevalence also varied with the origin of the animals, as 56.2% of the animals captured on farms, 38.6% of the ones captured at harbour sites and 11.8% of the animals captured from urban areas were bacteremic. Through molecular analysis of the gltA gene and 16S/23S intergenic spacer region, genetic diversity of Bartonella organisms was identified, including strains closely related to Bartonella tribocorum, Bartonella grahamii, Bartonella elizabethae, Bartonella phoceensis and Bartonella rattimassiliensis. Moreover, this is the first report of zoonotic B. elizabethae and B. grahamii identified in R. losea, the lesser rice-field rat. Various Bartonella species were identified in R. norvegicus, compared to 97.2% of Suncus murinus with unique Bartonella species. By indirect immunofluorescence antibody test, using various rodent Bartonella species as antigens, consistently low percentage of seropositivity implied that small mammals may play a role as competent reservoirs of Bartonella species in Taiwan. Future studies need to be conducted to determine whether these Bartonella species would be responsible for human cases of unknown fever or febrile illness in Taiwan, especially zoonotic B. elizabethae and B. grahamii.