Trend in seroprevalence of HTLV-1/2 in Taiwanese blood donors-A 10-year follow-up.

OBJECTIVES: This study evaluated the Human T-lymphotropic virus (HTLV) screening policy impact on the HTLV seroprevalence from 2009 to 2018 as well as the differences between administrative districts in terms of prevalence distribution in Taiwan. BACKGROUND: Since February 1996, the Taiwan Blood Services Foundation (TBSF) had conducted HTLV screening of blood donors. The HTLV seroprevalence was 0.032% in 1999. MATERIALS AND METHODS: This cross-sectional study included donors' data collected from blood donation centres across Taiwan from 2009 to 2018. Enzyme immunoassay and Western blot assay were used for screening and confirmation of HTLV infections. In this study, the researchers calculated the trends in the HTLV rates of first-time and repeat donors across time as well as the HTLV prevalence distribution across the 22 administrative districts of Taiwan. RESULTS: Amongst 17 977 429 employed blood donations, 739 HTLV-seropositive donations (4.11 per 100 000 donations) were identified. The HTLV-positive donors were aged between 17 and 64 years, with a median age of 49 years. The overall seropositivity rates of first-time and repeat donors were 34.36/100 000 and 1.27/100 000. HTLV seroprevalence in first-time blood donors significantly decreased by 57% (crude odds ratio [95% confidence interval] (crude OR [95% CI]) = 0.43 [0.28-0.64]) within 10 years. A slight decline was also identified in repeat donors (crude OR [95% CI] = 0.73 [0.4-1.32]). Donors from different districts showed significantly varied prevalence. Most districts with high prevalence are situated in eastern Taiwan, for both donation types. Older blood donors were more likely to be infected with HTLV than younger ones in first time and repeat donors. Middle age donors (50-65 years) had an 18.47-39.65 greater risk than those aged <20 years. Significant higher risk of female was observed in both donation types. Amongst different age groups, first-time female donors increase 1.31-1.88 times infection risk and female in repeat donor group had 1.55-3.43 times greater risk. CONCLUSION: Over years of implementation of the HTLV blood donor screening policy by the TBSF, the HTLV seroprevalence of first-time donors has decreased consistently. Moreover, the HTLV seroprevalence of repeat donors has dropped considerably. This implies that the screening policy provides continued benefit. Females and older blood donors were more likely infected with HTLV than males and younger blood donors. The influence of age on infection was greater amongst first-time donors than amongst repeat donors. Therefore, appropriate measures should be taken to ensure public safety.

Dengue Virus Ribonucleic Acid Detection Rates in Blood Donors Correlate With Local Infection Incidences During a Dengue Outbreak in Taiwan.

BACKGROUND: Evidence for mitigation of transfusion-transmitted dengue informed by surveillance data is lacking. In this study, we evaluated the risk of positive dengue viral (DENV) ribonucleic acid (RNA) from blood transfusions during a large outbreak in Taiwan. METHODS: Serum collected from blood donors living in districts experiencing the dengue epidemic were tested for DENV RNA using a qualitative transcription-mediated nucleic acid amplification assay (TMA). The TMA-reactive specimens were further tested for immunoglobulin (Ig)M and IgG antibodies, nonstructural protein 1 (NS1) antigen, and viral RNA by reverse-transcription polymerase chain reaction. We estimated DENV RNA prevalence and the number of DENV infections among blood donors. RESULTS: A total of 4976 specimens were tested for DENV RNA, and 21 were TMA-reactive. The detection rate was 0.84 (95% confidence interval [CI], 0.15-4.73), 3.36 (95% CI, 1.31-8.60), and 6.19 (95% CI, 3.14-12.17) per 1000 donors in districts where the weekly dengue incidence was 5-50, 50-200, and 200 or more per 100 000 residents, respectively. Alanine aminotransferase screening only detected 4.4% of TMA-reactive donations. A total of 143 transfusion-transmitted DENV infections probably occurred during this outbreak, accounting for 9.2 in 10 000 dengue infections. CONCLUSIONS: Approximately 0.5%-1% of blood donations were DENV RNA positive in epidemic districts. The correlation of DENV RNA rates with dengue incidence may inform the design of effective control measures.

Predictors for Early Identification of Hepatitis C Virus Infection.

Hepatitis C virus (HCV) infection can cause permanent liver damage and hepatocellular carcinoma, and deaths related to HCV deaths have recently increased. Chronic HCV infection is often undiagnosed such that the virus remains infective and transmissible. Identifying HCV infection early is essential for limiting its spread, but distinguishing individuals who require further HCV tests is very challenging. Besides identifying high-risk populations, an optimal subset of indices for routine examination is needed to identify HCV screening candidates. Therefore, this study analyzed data from 312 randomly chosen blood donors, including 144 anti-HCV-positive donors and 168 anti-HCV-negative donors. The HCV viral load in each sample was measured by real-time polymerase chain reaction method. Receiver operating characteristic curves were used to find the optimal cell blood counts and thrombopoietin measurements for screening purposes. Correlations with values for key indices and viral load were also determined. Strong predictors of HCV infection were found by using receiver operating characteristics curves to analyze the optimal subsets among red blood cells, monocytes, platelet counts, platelet large cell ratios, and mean corpuscular hemoglobin concentrations. Sensitivity, specificity, and area under the receiver operator characteristic curve (P < 0.0001) were 75.6%, 78.5%, and 0.859, respectively.

Risk factors of sensitization to human leukocyte antigen in end-stage renal disease patients.

BACKGROUND: Pre-sensitization to human leukocyte antigen (HLA) is closely related to the prognosis of renal transplantation. Concerning the risk factors for HLA sensitization, most studies focused only on selected transplant candidates. METHODS: All patients with end-stage renal disease (ESRD) in a single teaching hospital and a group of healthy subjects were enrolled for the tests of panel-reactive antibodies (PRA). RESULTS: A total of 1177 subjects were recruited, including 289 ESRD patients (140 hemodialysis, 98 peritoneal dialysis, and 51 pre-dialysis) and 888 healthy volunteers. The prevalence of PRA positivity (for either type I or II HLA) for ESRD patients was higher than for healthy subjects (23.2% vs. 12.8%, p=0.000). Only pregnancy and transfusion showed independent correlations with PRA positivity, and not ESRD itself. The PRA-positive ESRD patients were prone to be female, have histories of pregnancy, transfusion, no hepatitis B, and use of graft shunt for dialysis. Multivariate analyses showed that pregnancy and time interval of the latest transfusion had independent correlations with PRA positivity. The time interval of less than 1 year had the highest odds ratio 10.06 (p=0.000). CONCLUSIONS: Pregnancy and recent transfusion, not ESRD itself or dialysis modality, remain the independent risk factors for HLA sensitization.

Low accuracy of the national reporting system of acute hepatitis C infection in Taiwan, 1995-2004.

BACKGROUND AND AIM: This study attempted to clarify accuracy of acute hepatitis C (AHC) and its clinical characteristics. METHODS: We reviewed 632 reported cases from national surveillance data of the Taiwan Center for Disease Control between 1995 and 2004, and reclassified diagnoses. A definite case was defined as alanine aminotransferase (ALT) > 10 x the upper limit of normal (ULN) with seroconversion of anti-hepatitis C virus antibody (anti-HCV). A probable case was defined as (i) seroconversion of anti-HCV and/or elevated ALT levels; or (ii) anti-HCV(+) but titers increased (from < 40 S/CO to >or= 40 S/CO) and ALT > 10 x the ULN. A suspected case was defined as initial anti-HCV(+) and ALT level > 10 x the ULN and/or jaundice. Excluded cases were defined as ALT levels less than 10 x ULN with initial positive anti-HCV Ab. RESULTS: A total of 310 (49%) cases were confirmed as AHC; these included 95 (15%) definite and 215 (34%) probable cases. Higher incidence rates and accuracy of AHC were demonstrated in the southern area significantly if compared with northern, eastern and central areas, respectively (all P < 0.05). On comparison between blood centers and hospitals, more AHC cases were found in Southern Taiwan than in other areas (157/73 vs 24/40, P < 0.001), younger mean age (33.3 +/- 11.1 vs 49.3 +/- 16.4, P < 0.001), lower ALT levels (263.1 +/- 200.9 vs 1264.2 +/- 706.8, P < 0.001) and male predominance (191/39 vs 46/18, P = 0.046). CONCLUSIONS: This study showed our reporting system over-estimated the AHC diagnosis, which is also a common issue worldwide. Greater efforts are needed to establish appropriate reporting systems, as well as more supplemental methods to distinguish between prevalent and incident cases.

Papulolinear collagenoma with arborizing arrangement: report of a case.

Connective tissue nevi of collagen type are now classified in four major subtypes. In addition to the clinicopathological features of papulolinear collagenoma, which is considered as a variant of isolated collagen harmatoma, the case we present has a unique arborizing pattern.

Double-pass high-gain low-noise EDFA over S- and C+L-bands by tunable fundamental-mode leakage loss.

We demonstrate a high-gain low-noise double-pass tunable EDFA over S- and C+L-bands by discretely introducing fundamental-mode leakage loss in a 16-m-long standard C-band Er(3+)-doped fiber. The amplified spontaneous emission at the wavelengths of longer than 1530 nm can be substantially attenuated by the ASE suppressing filters to maintain high population inversion and to squeeze out the optical gain for S-band signals. When the filters are disabled, the gain bandwidth immediately returns back to the C+L-bands. Under S-band operation, a 37 dB small signal gain and a minimum 4.84 dB noise figure at 1486.9 nm are achieved with a 980 nm pump power of 154 mW.

Towards the short-wavelength limit lasing at 1450 nm over 4I13/2 ? 4I15/2 transition in silica-based erbium-doped fiber.

The transition rate of the stimulated emission at the higher energy levels of the excited states in a silica-based erbium-doped fiber can be enhanced by introducing fundamental-mode cutoff filtering mechanism. The electrons excited by optical pumping can more occupy the higher energy levels of the excited states when the transition rate for the lower energy levels (longer wavelengths) of the excited states is substantially suppressed. The achieved lasing wavelength can thus be moving toward the shorter wavelengths of the gain bandwidth. The laser transition between 4I13/2 ? 4I15/2 multiplets of the silica-based erbium-doped fiber is known to emit fluorescence with the shortest wavelength around 1450 nm. We, for the first time, experimentally demonstrate a widely tunable fiber laser at the wavelength very close to 1450 nm by using a standard silica-based C-band erbium-doped fiber. The tuning range covers 1451.9-1548.1 nm, with the best temperature tuning efficiency as high as 57.3 nm/ degrees C, by discretely introducing tunable fundamental-mode cutoff tapered fiber filters along a 16-m-long erbium-doped fiber under a 980 nm pump power around 200 mW. The signal-ASE-ratio can be higher than 45 dB whereas the FWHM of the laser lasing lights can be reduced below 0.2 nm by using an additional Fabry-Perot filter.