Emerging infections in Asia and its possible global effects

Abstract

Challenges continue to arise in maintaining a safe and sufficient blood supply. The nature of these challenges has changed during the current decade. In the late 20th century the focus was on managing risks related to well recognised pathogens such as HIV and the hepatitis viruses (B and C). Continued vigilance is needed in these areas. A range of new concerns are however emerging. A number of factors are contributing to this. These include the impact of globalisation of commerce and the increased travels associated with this, the impact of climate change and in some instances advances in technology that enable us to intervene more effectively to address long standing blood safety concerns. Improvements in technologies can also provide an opportunity to address known risks more effectively e.g. the introduction of HBV DNA testing to identify donors with Occult Hepatitis B infection. Emerging infections can impact on blood services in a number of ways. Firstly they might be readily transmissible by transfusion of blood components. Secondly, they can reduce significantly the availability of donors leading to potential or real shortages of blood components for transfusion and finally the infections can lead to an increased demand for blood components. In practice many agents will impact in a number of ways. Asia is the most populous continent. Infections emerging in this environment can quickly lead to global safety concerns. Current concerns include Dengue Fever, arthropod borne infections such as Chikungunya virus, Hepatitis E virus and new influenza strains including the Novel A H1N1 09 strain. Occult hepatitis B and malaria also continue to present challenges for blood services in the region. Dengue infection is caused by a flavivirus that is spread by mosquito, primarily Aedes aegypti. The infection is seasonal and is widespread in Asia, South America, Africa and increasingly in the Pacific. There is now good evidence that is transmissible by transfusion and the virus can be detected in the blood of asymptomatic blood donors. Nucleic acid based tests are currently being developed. Chikungunya virus is an alpha virus transmitted by Aedes aegypti and albopictus mosquitos. Interest in the agent increased following large outbreaks in Reunion Island and northern Italy. The primary impact on blood services is a severe temporary shortage of donors. Hepatitis E virus is predominantly spread by the faeco oral route. Recent outbreaks in the Hokkaido region of Japan linked to eating pork products have provided evidence that it can be transmitted by transfusion. Pandemic influenza remains a real concern for public health services. Initially this related to the H5N1 avian influenza strain. The emergence of novel influenza strain H1N1 09 in 2009 and the resulting pandemic have inevitably raised questions for blood services. Blood services will need to develop effective strategies to manage the risk associated with emerging agents. This might include donor exclusion criteria and testing of selected donations. Pathogen reduction systems also provide a highly effective mechanism to manage the impact of these agents.