[Emergent viral threats in blood transfusion]

West Nile virus and blood transfusion safety: A European perspective

BACKGROUND AND OBJECTIVES

There is a growing concern for the transmission of arboviral infections by blood transfusion in Europe. However, no assessment of the risk of transmission through all European blood supplies has been reported. Risk regulations at a European level should take differences in local transmission risk and the risk of transmission by travelling donors into consideration.

MATERIALS AND METHODS

A risk model and publicly available tool were developed to calculate the risk of transmission by all European blood supplies for arboviral outbreaks within Europe. Data on individual European blood supplies from Council of Europe reports and inter-European travel data from EUROSTAT were used to populate this model.

RESULTS

Each neuroinvasive case of WNV reported in Europe will on average result in 0·43 (95%CI: 0·32-0·55) infected blood product by locally infected donors and 0·010 (95%CI: 0·006-0·015) infected products by travelling donors. On basis of the 1373 neuroinvasive human WNV cases reported in the outbreak of 2018, it is estimated that without safety interventions this outbreak would have resulted in 708 (95%CI: 523-922) infected components derived from resident donors. Noncompliance to European regulations, which requires donor deferral or testing of donors who visited WNV-infected areas, would have resulted in 7.4 (95%CI: 4·7-11·1) infected blood components derived from infectious travelling donors exposed in outbreak areas throughout Europe.

CONCLUSION

The risk of WNV transmission by a local outbreak is on average 113 times (95%CI: 95-139), so two orders of magnitude higher than the risk of transmission by travelling donors in Europe.

Dengue virus serological markers among potential blood donors: an evidence of asymptomatic dengue virus transmission in Cameroon

Introduction

the risk of dengue virus or its antibodies which can be transmitted through blood transfusion by asymptomatic individuals infected, has been a major concern all over the world. Dengue is an endemic disease in sub-Saharan Africa, particularly in Cameroon. The purpose of this study is to determine the frequency of dengue virus (DENV) infection among potential blood donors at Yaounde Jamot Hospital.

Methods

serum samples were collected from 310 potential adult blood donors aged 18-57 years, who signed a written informed consent and completed the questionnaire between March 2019 and August 2019. This serum is used to screen for the presence of serological markers of DENV infection (NS1, IgM and IgG) using immunochromatographic tests (Zhuhai Encode Medical Engineering Co., Ltd, China). IgM/IgG positive samples were confirmed by enzyme-linked immunosorbent assays (ELISA).

Results

the overall prevalence was 24.8% among potential blood donors were subdivided as follows: 4.5% (14/310), 12.3% (38/310) and 6.1% (19/310) showed mono-positivity to DENV-NS1 antigen, anti-DENV IgM and anti-DENV IgG antibodies respectively. 1.9% (6/310) of potential blood donors showed dual positivity to anti-DENV IgM antibodies and anti-DENV IgG antibodies. The presence of DENV-NS1 antigen show asymptomatic viremia of dengue at the time of donation, while the presence of IgG antibodies reflects the high endemicity of dengue disease in the city of Yaoundé.

Conclusion

these findings demonstrate the high level of risk of the DENV transmission among potential blood donors to needy recipients, underscoring the importance of establishing dengue fever blood screening in different services and blood collection units in Cameroon to improve safety transfusion and control the dissemination of the DENV.

Seroprevalence of Asymptomatic Dengue Virus Infection and Its Antibodies Among Healthy/Eligible Saudi Blood Donors: Findings From Holy Makkah City

BACKGROUND

Threat to blood transfusion-transmitted dengue virus (DENV) and its antibodies has recently emerged worldwide. Dengue fever is an endemic disease in Saudi Arabia, particularly in its Western region. The aim of this study was to estimate the seroprevalence of asymptomatic DENV infection and its antibodies among eligible Saudi blood donors.

METHODS

Serum samples from 910 healthy/eligible adult male Saudi blood donors, who reside in Holy Makkah City of Saudi Arabia, were collected between March 2015 and August 2016 and screened for the detection of DENV nonstructural protein 1 (NS1) antigen and anti-DENV IgM and IgG antibodies using commercial enzyme-linked immunosorbent assay kits (Panbio, Brisbane, QLD, Australia).

RESULTS

Among the tested donors, 48 (5.3%) were seropositive for DENV-NS1 antigen, whereas 50 (5.5%) and 354 (38.9%) were seropositive for anti-DENV IgM and IgG antibodies, respectively. Seropositivity for DENV-NS1 antigen and/or anti-DENV IgM antibody among the tested donors reflects their ongoing asymptomatic viremic infectious stage with DENV during their donation time, whereas high prevalence of anti-DENV IgG seropositivity reflects the high endemicity of dengue disease in this region of Saudi Arabia.

CONCLUSIONS

These results show high prevalence of asymptomatic DENV infection and its antibodies among Saudi blood donors, raising the importance of establishing blood screening for dengue disease at different blood donation services and units in Saudi Arabia to improve the guarantee of blood transfusions and to control DENV dissemination.

The infectious risks in blood transfusion as of today - A no black and white situation

Transfusion has been tainted with the risk of contracting an infection - often severe - and fears about this risk are still prevailing, in sharp contrast with the actual risk in Western countries. Those actual risks are rather immunological, technical (overload) or metabolic. Meanwhile, in developing countries and particularly in Africa, transfusion transmitted infections (TTIs) are still frequent, because of both the scarcity of volunteer blood donors and resources and the high incidence and prevalence of infections. Global safety of blood components has been declared as a goal to be attained everywhere by the World Heath Organization (WHO). However, this challenge is difficult to meet because of several intricate factors, of which the emergence of infectious agents, low income and breaches in sanitation and hygiene. This review aims at encompassing the situation of TTIs in different settings and means that can be deployed to improve the situation where this can possibly be.

[New viral risks in blood transfusion by 2016]

Viral safety remains a major concern in transfusion of blood products. Over years, the control measures applied to blood products were made more and more sophisticated; however, the number of infectious agents, and notably of viruses, that can be transmitted by transfusion is increasing continuously. The aim of this review paper is to actualize that published in the same journal by the same authors in 2011 with more details on some of actual vs virtual viral threats that were identified recently in the field of blood transfusion. The main subjects that are covered successively concern the transmission via transfusion of hepatitis E virus, the frequency of transfusion transmitted arboviruses, transfusion at the time of the Ebola epidemics in West Africa, the debated role of Marseillevirus (giant viruses infecting amoebae and suspected to infect human blood latently), and, finally, the recent report of the identification in blood donors of a new member of the Flaviviridae family. The addition of these new viral risks to those already identified-partially controlled or not-pleads for the urgent need to move forward to considering inactivation of infectious agents in blood products.

Seroepidemiology of hepatitis B and C viruses in the general population of burkina faso

Objectives. In Burkina Faso, few studies reported the prevalence of HBV and HCV in the general population. This study aimed to evaluate the prevalence of hepatitis B and C viruses in the general population and to determine the most affected groups in relation to the risk factors associated with the infection. Method. A voluntary testing opened to anyone interested was held at Saint Camille Medical Centre in Ouagadougou. Rapid tests were carried out on 995 persons who voluntarily answered a range of questions before the venous blood sampling. Results. The results revealed that the antigen HBs carriers in the general population represented 14.47% (144/995) and the prevalence of HCV was 1.00% (10/995). The difference between HBV's prevalence in men (18.58%) and that in women (11.60%) was statistically significant (P = 0.002). The most affected groups were undergraduated students (19.57%) and persons working in the informal sector (15.98%). The least affected group was high level students (8.82%). Conclusion. Burkina Faso is a country with a high prevalence of HBV, while the incidence of HCV is still low in the general population. Therefore, more campaigns on the transmission routes of HBV and HCV are needed to reduce the spread of these viruses in sub-Saharan Africa.

Molecular HIV screening

Nuclear acid testing is more and more used for the diagnosis of infectious diseases. This paper focuses on the use of molecular tools for HIV screening. The term 'screening' will be used under the meaning of first-line HIV molecular techniques performed on a routine basis, which excludes HIV molecular tests designed to confirm or infirm a newly discovered HIV-seropositive patient or other molecular tests performed for the follow-up of HIV-infected patients. The following items are developed successively: i) presentation of the variety of molecular tools used for molecular HIV screening, ii) use of HIV molecular tools for the screening of blood products, iii) use of HIV molecular tools for the screening of organs and tissue from human origin, iv) use of HIV molecular tools in medically assisted procreation and v) use of HIV molecular tools in neonates from HIV-infected mothers.

[The expansion of vector-borne diseases and the implications for blood transfusion safety: The case of West Nile Virus, dengue and chikungunya]

Arbovirus infections are increasing in prevalence worldwide. This presents new risks for blood transfusion. This article describes the epidemiology and surveillance of West Nile Virus, dengue and chikungunya and their role in the risk management of transfusions. Arboviruses are RNA viruses and very adaptable by nature. The majority of arbovirus infections are zoonoses. The risk of transmission is multifactorial and concerns the virus, vectors, animal reservoirs, the environment and human behaviour. In recent years, West Nile Virus has become established and widespread in North America, the number of cases of dengue worldwide has increased dramatically, and major epidemics of chikungunya have occurred in the Indian Ocean and Asia. The transmission of dengue and chikungunya is demonstrated in temperate zones. All arboviruses are potentially transmissible by transfusion due to their capacity to induce an asymptomatic viremic phase. The risk of West Nile Virus transmission via transfusion is recognised and prevention measures are well established. The risk of transmission via transfusion of dengue and chikungunya is real but difficult to quantify and the optimum prevention strategy is currently the subject of research. Access to up-to-date epidemiological data is an essential aid to decision-making, especially for donors returning from endemic areas to Europe. The challenge is to define and implement appropriate measures in unpredictable situations.

Seroprevalence of hepatitis E antibodies and risk profile of HEV seropositivity in The Netherlands, 2006–2007

Hepatitis E virus (HEV) is now considered an endemic pathogen in industrialized countries, leading to acute and sometimes chronic hepatitis, mostly in vulnerable people. The endemic sources are unclear. A survey in The Netherlands in 2006–2007 showed a 1·9% seroprevalence of HEV antibodies measured by ELISA and confirmed by immunoblot in a nationwide sample. Overall, in 134/7072 (1·9%) seropositive individuals, older age (P<0·01), being male (P<0·01), working with patients (P=0·03), working with animals (P=0·07), recent diarrhoeal complaints (P=0·07) and adhering to a religion that considers pigs unclean (P<0·01) were independently associated with seropositivity in multivariate analysis. Sub-analysis of 59/4022 (1·5%) anti-HEV antibody-positive subjects with probable endemic exposure showed independent association with youngest household member being aged <5 years or between 19 and <65 years (P=0·05) in multivariate analysis. These findings may contribute to a better understanding of the sources of endemic HEV exposure, and also highlight the need for systematic epidemiological and serological evaluation of new cases.