Risk of chikungunya virus transmission associated with European travelers returning from southern Thailand (2008-2015).

BACKGROUND: The impact of the spread of chikungunya virus (CHIKV) by autochthonous transmission and blood transfusion in nonendemic areas via travelers returning from CHIKV-affected locations is a concern. METHODS: We analyzed the risks of potential CHIKV importation and transfusion transmission from Thailand to Europe via travelers visiting southern Thailand from 2008 through 2015, using the web-based European Up-front Risk Assessment Tool. RESULTS: The risk of CHIKV importation by European travelers returning from Thailand from 2008 through 2015 varied depending on the year of travel, tourist destination, duration of stay, and time since last possible exposure. Specifically, the risks of acquiring CHIKV among travelers visiting Songkhla and Krabi for 1, 5, or 10-30 days during the highest epidemic activity in 2009 were estimated to be 74.40, 371.99, and 706.77 (Songkhla) and 1.82, 9.08, and 17.25 (Krabi) per 100,000 travelers, respectively. In contrast, such risks were estimated to be fewer than 0.099 per 100,000 travelers in nonepidemic years. The 2009 yearly average rates of expected incidence among 4,059,988 European travelers who stayed for 1 or 10-30 days in all six outbreak activity destinations were calculated to be, respectively, 4.01 × 10-6 or 1.20 × 10-4 cases per day, corresponding to the estimated rates of viremia and transfusion-transmitted CHIKV via traveling blood donations of 3.21 × 10-5 and 0.61, and 9.62 × 10-4 and 3.34, respectively. Additionally, it is probable that 18 (0.0004%) Europeans acquired CHIKV in Thailand, representing a maximum attack rate of 0.0023%. CONCLUSION: The extent of the expected risks and attack rates of CHIKV infection might reflect the travel preferences for popular destinations rather than the true risks of CHIKV transmission in travelers' home nonendemic countries. Nevertheless, preventive and blood-safety intervention measures may be applied to returning travelers at risk for infection to reduce CHIKV transfusion threats in their home countries.

Risk of transfusion-transmitted chikungunya infection and efficacy of blood safety implementation measures: experience from the 2009 epidemic in Songkhla Province, Thailand.

BACKGROUND: To date, neither is there a standard guideline for maintaining a safe blood supply during a chikungunya fever (CHIKF) outbreak nor has a study been performed on actual transfusion-transmitted CHIKF to recipients. This study estimated the potential incidence of transfusion-transmitted CHIKF and compared the efficacies of various blood safety intervention strategies to mitigate the transfusion-transmitted CHIKF risk. STUDY DESIGN AND METHODS: A Web-based tool named the European Up-Front Risk Assessment Tool (EUFRAT) was used to estimate the risk of transfusion-transmitted CHIKF using data inputs from the 2009 Songkhla epidemic in Thailand. RESULTS: The mean and maximal risks of viremic donations during the entire epidemic period were estimated to be 0.9 (95% confidence interval [CI], 0.0-2.7) and 4.8 (95% CI, 0.5-9.1), respectively. This meant that the potential risk of transfusion-transmitted CHIKF to recipients receiving all infective end products in the absence of blood safety measures was from 10.9 (95% CI, 1.8-20.4) to 57.6 (95% CI, 36.4-79.5). Based on experience from the 2009 Thai epidemic, the proportion of 10% asymptomatic cases, for instance, with predonation screening for CHIKF-related symptoms and follow-up observation in donors at risk was estimated to be 88.4% (95% CI, 69.9%-100.0%) to 99.1% (95% CI, 79.6%-100.0%) effective in reducing this transfusion risk compared to 83.7% (95% CI, 65.8%-100.0%) to 90.7% (95% CI, 72.1%-100.0%) by predonation screening for donors at risk of chikungunya virus infection alone. CONCLUSION: This study suggests that prompt blood screening measures can reduce the risk of transfusion-transmitted CHIKF and maintain a safe blood supply during an outbreak.

Viremic profiles in asymptomatic and symptomatic chikungunya fever: a blood transfusion threat?

BACKGROUND: The presence of a chikungunya virus (CHIKV) outbreak could have an impact on transfusion safety when there are a large number of infected persons during an epidemic. Serosurveys have found that 3% to 28% of infected persons remain asymptomatic and are potential disseminators of transfusion-associated chikungunya. However, the viremic profiles of asymptomatic chikungunya patients, the major determinant of the transfusion risk, are unknown. STUDY DESIGN AND METHODS: Data on CHIKV viremic profiles were obtained from a case-control study carried out in a chikungunya-affected area during the 2009 epidemic in Songkhla, Thailand. CHIKV-infected individuals were classified based on a combination of the patient's history and clinical and laboratory findings. RESULTS: There were 134 laboratory-proven CHIKV-infected cases, of whom 122 (91.0%) were symptomatic and 12 (9.0%) were asymptomatic. The viremic levels in the symptomatic infected individuals peaked on the first 3 days and lasted up to 8 days as defined by viral isolates. CHIKV genomic products were detected as late as Day 17 of illness. The viral loads observed in the symptomatic individuals (median, 5.6 × 10(5) plaque-forming units per milliliter [pfu/mL]; range, 1.3 × 10(1) -2.9 × 10(8) pfu/mL) were higher than but not significantly different from those observed in the viremic asymptomatic individuals (median, 3.4 × 10(3) pfu/mL; range, 8.4 × 10(1) -2.9 × 10(5) pfu/mL [p = 0.22, Wilcoxon test]). CONCLUSION: CHIKV infection is highly symptomatic and is associated with high-titred viremia. The viremic levels in asymptomatic CHIKV-infected individuals were in the range known to be capable of transmitting the disease to experimental animals. Asymptomatic CHIKV viremia individuals could be potential disseminators of transfusion-associated chikungunya.

The serum squamous cell carcinoma antigen level in inverted sinonasal papilloma and nasal polyps patients.

OBJECTIVE: To clarify whether the serum squamous cell carcinoma antigen (SCCA) levels of patients with inverted papilloma (IP) are different from patients with nasal polyps (NP) and rhinitis. MATERIALS AND METHODS: Serum SCCA levels were measured in 30 patients with IP and 30 patients with NP at one day before surgery and seven days after surgery and measured in 28 patients with rhinitis. RESULTS: Elevated serum SCCA levels (>1.5 ng/ml) were found in 80.0% of patients in the IP group, 6.7% of patients in the NP group and 14.3% of patients in the rhinitis group, which was a significant difference. The medians of serum SCCA levels in the IP, NP and rhinitis groups were 3.9, 0.8 and 1.1 ng/ml, respectively, which was a significant difference. The SCCA level in IP group was not significantly correlated according to Krouse Staging. There was a significant difference in serum SCCA levels between the pre- and postoperative stages in the IP group, at 3.9 and 0.8 ng/ml, respectively, while in the NP group the levels were 0.8 and 1.0 ng/ml, not significantly different. With regard to the IP diagnosis in the IP and NP group based on the SCCA level (>1.5 ng/ml), sensitivity and specificity was 80.0% and 93.3%, respectively. CONCLUSIONS: The serum SCCA level in patients with IP was elevated and then it decreased after surgery. This was different from NP and rhinitis patients who mostly had normal levels, which did not change.

A prospective evaluation of four immunodiagnotic assays for human leptospirosis.

This was a prospective evaluation of four immunodiagnostic assays for human leptospirosis, including the indirect immunofluorescence test (IFA), the microscopic agglutination test (MAT), the LEPTO dipstick, and the latex agglutination (LA) test. Four hundred ninety-two serum samples were collected from 348 patients who presented with acute fever without localizing signs. The sensitivities of the IFA, MAT, Dipstick, and LA were 91.9, 76.6, 77.4, and 83.1%, respectively. The specificities of these assays were 100.0, 100.0, 89.3, and 83.5, respectively. Even though IFA showed the highest overall sensitivity and specificity, when acute sera were considered, the LA was the most sensitive (28.7%). All 3 genus specific antibody assays had broad reactivity against various serogroups. The MAT is best suited for the reference laboratory, where it can be maintained with the battery of live antigens; the IFA is suited for a laboratory with sophisticated equipment and technical expertise; the Dipstick and LA are suitable for peripheral laboratories which lack expensive equipment and expertise.