Autor(es): Andonov A.

Resumo: Arboviruses capable of causing large and often explosive outbreaks represent an important new challenge to the safety of the blood supply. The new era of globalization, massive urbanization, poverty, climate change, international travel, colonization by Aedes Albopictus mosquito of new territories both in tropical and temperate regions, insecticide resistance are among the main factors contributing to reemerging arborical diseases. Most if not all arboviruses have a relatively short viremic phase during the course of infection, but perhaps more importantly asymptomatic viremia may precede the onset of clinical disease by 1-2 days and therefore deferral of donors with potential unrecognized infection is undoable. Further to that arboviral infection is often asymptomatic and in the absence of suitable donor screening assays transfusion risk of infection may be considerable. Arboviruses like other RNA viruses have remarkable genomic plasticity and propensity to adapt when infecting different mosquito vectors; a single mutation alanine substituted by valine (A226V) in the E1 envelope glycoprotein of Chikungunya virus (CHIKV) significantly increased the viral replication and dissemination in Ae. Albopictus thus enhancing the transmission efficiency of infection with that vector. Similar process of adaptation, although not of the same importance has been observed once WNV became established in US; a new dominant genotype of the virus named WN02 became increasingly prevalent since 2002 displacing the original NY99 strain possibly due to increased transmission efficiency of the new genotype with domestic North American mosquitos. There are also observations that some current Asian strains of Dengue virus (DENV) may be more virulent for humans compared to strains circulating in South America. The above mentioned evidence of the adaptive capacity of different arboviruses obviously increases the risk of their global incursion. Arbovirus transmission through transfusion of blood products from asymptomatic donors has been documented for West Nile Virus (WNV), Dengue Virus, Tick-borne encephalitis (TBEV) virus, Colorado Tick Fever (CTFV) virus, and recently Yellow Fever virus (vaccine strain). Arbovirus transfusion transmitted infections pose a credible risk to the safety of the blood supply and although it is impossible to predict which pathogen may be on the top of the priority list currently of greatest concern are Dengue virus, CHIKV, O'nyong nyong virus, Rift Valley Virus and Japanese encephalitis virus which are considered exotic arboviruses for the temperate climatic zones. A worrisome trend is that arboviral infections are on the rise both in terms of magnitude of affected populations as well as in variety of incursions of individual viruses rarely heard before; a good example is Usutu virus emergence in Europe or Zika virus in Micronesia. Public health will play a major role in preventing and/or sustaining arboviral incursions when they occur. Key to development of real-time warning system for vector borne diseases is adequate surveillance. Examples of excellent networks specifically targeting arbovirus ecology are ArboNet in US, the European Mosquito Control Association (EMCA), the European Network for Diagnostics of Imported Viral Diseases (ENIVD), EpiSouth, a network for the Mediterranean region and the Balkans, the National Arbovirus and Malaria Advisory Committee (NAMAC) in Australia.

Palavras-Chave: blood transfusion, society, transfusion, virus infection

Imprenta: Vox Sanguinis, v. 99 supl. 1, p. 31-32, jul. 2010

Descritores: Zika virus - Arbovirus ; Zika virus - Flaviviridae ; Zika virus - Pathogenesis ; Zika virus - RNA ; Zika virus - Viral infections ; Zika virus - RNA virus ; Zika virus - Transmission ; Zika virus - Vaccine ; Zika virus - Chikungunya Fever ; Zika virus - Public health ; Zika virus - Zika fever

Data de publicação: 2010

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