The Potential Impact of Chikungunya Virus Outbreaks on Blood Transfusion

Chikungunya virus seroprevalence in asymptomatic blood donors during an outbreak in the Federal District of Brazil

INTRODUCTION

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus belonging to the Togaviridae family. The symptomatic infection is characterised by acute febrile disease which generally results in severe arthralgia and myalgia, however, most of the CHIKV infections remain asymptomatic. CHIKV RNA detection in asymptomatic volunteers may be responsible for the transfusion transmission of this infection, especially during outbreaks. There is no information for CHIKV seroprevalence among blood donors from the Federal District of Brazil.

AIM

In early 2019, the Federal District of Brazil experienced a CHIKV outbreak, and this study evaluates the anti-CHIKV IgM and IgG presence in a well characterised cohort of blood donors from this region.

METHODOLOGY

Blood samples were collected from 450 volunteer blood donors during a CHIKV outbreak and tested for the presence of anti-CHIKV IgG and IgM antibodies using ELISA.

RESULTS

The CHIKV seroprevalence was 0.89% (n = 4/450) and anti-CHIKV IgM prevalence was 1.11% (n = 5/450).

CONCLUSION

The obtained results demonstrated that at least some of the blood donors have experienced CHIKV infection which can be related to a hypothetical risk of CHIKV transfusion transmission. More studies are necessary in order to examine the impact of CHIKV on blood transfusion.

Lack of Evidence of Chikungunya Virus Infection among Blood Donors during the Chikungunya Outbreak in Lazio Region, Italy, 2017

Background: The latest European Chikungunya virus (CHIKV) outbreak occurred in Italy in 2017, in the municipalities of Anzio and Rome (Lazio Region), with a secondary outbreak in the Calabrian Region. Most CHIKV infections are symptomatic but about 15% of people who acquire the infection may be asymptomatic. A retrospective study was conducted with the aim of assessing the prevalence of recent/ongoing CHIKV infections on the blood donor population in the Lazio Region, during the 2017 outbreak (including in the period before it was detected). Methods: The study was conducted on 4595 plasma samples from donors who donated in 14 different Blood Establishments in the Lazio Region, in the period June–November 2017. A total of 389 of these samples were collected in provinces not affected by the outbreak and were used as negative controls. All samples were tested for IgM detection by the use of an ELISA test, and positive samples were tested for confirmation through the use of a PRNT. Molecular tests were performed on sera that were found to be IgM-positive or borderline. Results: A total of 41 (0.89%) blood donors tested positive for IgM. None of these positive IgM ELISA results was confirmed either by PRNT or by molecular tests. Conclusions: Our study has shown no evidence of recent/ongoing CHIKV infection in blood donors of the affected area.

Past and future epidemic potential of chikungunya virus in Australia

Background

Australia is theoretically at risk of epidemic chikungunya virus (CHIKV) activity as the principal vectors are present on the mainland Aedes aegypti) and some islands of the Torres Strait (Ae. aegypti and Ae. albopictus). Both vectors are highly invasive and adapted to urban environments with a capacity to expand their distributions into south-east Queensland and other states in Australia. We sought to estimate the epidemic potential of CHIKV, which is not currently endemic in Australia, by considering exclusively transmission by the established vector in Australia, Ae. aegypti, due to the historical relevance and anthropophilic nature of the vector.

Methodology/Principal findings

We estimated the historical (1995–2019) epidemic potential of CHIKV in eleven Australian locations, including the Torres Strait, using a basic reproduction number equation. We found that the main urban centres of Northern Australia could sustain an epidemic of CHIKV. We then estimated future trends in epidemic potential for the main centres for the years 2020 to 2029. We also conducted uncertainty and sensitivity analyses on the variables comprising the basic reproduction number and found high sensitivity to mosquito population size, human population size, impact of vector control and human infectious period.

Conclusions/Significance

By estimating the epidemic potential for CHIKV transmission on mainland Australia and the Torres Strait, we identified key areas of focus for controlling vector populations and reducing human exposure. As the epidemic potential of the virus is estimated to rise towards 2029, a greater focus on control and prevention measures should be implemented in at-risk locations.

Chikungunya virus (CHIKV) is transmitted primarily by Aedes aegypti and Aedes albopictus mosquitoes and causes a potentially debilitating febrile and arthralgic disease. The virus is a threat to public health in regions where the primary vectors are established, as evidenced by past epidemics in the Indian Ocean Islands, South America and the Caribbean. In Australia, there are established populations of Ae. aegypti both on the mainland and in the Torres Strait, and of Ae. albopictus in the Torres Strait. This provides a theoretical potential for CHIKV transmission, as seen historically with dengue virus (DENV). It is therefore important to understand the epidemic potential of CHIKV in Australia. We estimated the basic reproduction number (R₀) of CHIKV during the years 1995–2019 for 11 Urban Centres and Localities (UCLs) in Australia, and found that Brisbane, Cairns, Darwin, Rockhampton, Thursday Island, and Townsville were all susceptible to CHIKV epidemics. We then forecasted epidemic potential from 2020–2029 and found an increase in R₀ across the six main UCLs. By highlighting factors that significantly influence the epidemic potential of CHIKV in Australia, our study supports evidence-based decision making for vector control and public health programs.

Overview on Chikungunya Virus Infection: From Epidemiology to State-of-the-Art Experimental Models

Chikungunya virus (CHIKV) is currently one of the most relevant arboviruses to public health. It is a member of the Togaviridae family and alphavirus genus and causes an arthritogenic disease known as chikungunya fever (CHIKF). It is characterized by a multifaceted disease, which is distinguished from other arbovirus infections by the intense and debilitating arthralgia that can last for months or years in some individuals. Despite the great social and economic burden caused by CHIKV infection, there is no vaccine or specific antiviral drugs currently available. Recent outbreaks have shown a change in the severity profile of the disease in which atypical and severe manifestation lead to hundreds of deaths, reinforcing the necessity to understand the replication and pathogenesis processes. CHIKF is a complex disease resultant from the infection of a plethora of cell types. Although there are several in vivo models for studying CHIKV infection, none of them reproduces integrally the disease signature observed in humans, which is a challenge for vaccine and drug development. Therefore, understanding the potentials and limitations of the state-of-the-art experimental models is imperative to advance in the field. In this context, the present review outlines the present knowledge on CHIKV epidemiology, replication, pathogenesis, and immunity and also brings a critical perspective on the current in vitro and in vivo state-of-the-art experimental models of CHIKF.

Detection of dengue, chikungunya, and Zika RNA in blood donors from Southeast Asia

BACKGROUND

Chikungunya (CHIKV), dengue (DENV), and Zika (ZIKV) viruses are of concern due to the potential of transfusion transmission in blood, especially in regions such as Southeast Asia where the viruses are endemic. The recent availability of nucleic acid testing (NAT) to screen blood donations on an automated platform provides the opportunity to detect potentially infectious units in asymptomatic donors.

STUDY DESIGN AND METHODS

Three thousand blood donations from Vietnam and 6000 from Thailand were screened with a real-time polymerase chain reaction (PCR) test (cobas CHIKV/DENV, Roche Diagnostics, Indianapolis, IN) and equal numbers on cobas Zika (Roche Diagnostics). Reactive samples were tested by alternative NAT with resolution of discordant results by heminested PCR. Throughput of simultaneous testing of the two assays on the cobas 8800 system (Roche Diagnostics) was evaluated.

RESULTS

In Vietnam, 9 of 3045 samples were reactive for DENV and all were confirmed, for a prevalence (with 95% confidence interval [CI]) of 0.296% (0.135-0.560). In Thailand, 2 of 6000 samples were reactive for CHIKV, 4 of 6000 for DENV, and 1 of 6005 for ZIKV, and all confirmed. The prevalence of CHIKV is 0.033% (0.004-0.120), DENV 0.067% (0.018-0.171), and ZIKV 0.017% (0.000-0.093). The overall specificity for the cobas CHIKV/DENV and cobas Zika tests was 100% (99.959-100). For the simultaneous assay testing, 960 test results were available in 7 hours and 53 minutes.

CONCLUSION

Detection of CHIKV, DENV, and ZIKV RNA in donor samples in Vietnam and Thailand indicate the presence of the virus in asymptomatic blood donors. The cobas 6800/8800 systems (Roche Molecular Systems, Pleasanton, CA) enable screening blood donations in endemic areas for these viruses together or separately.