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Zika Virus: the Latest Newcomer.

Saiz JC, Vázquez-Calvo Á, Blázquez AB, Merino-Ramos T, Escribano-Romero E, Martín-Acebes MA - Front Microbiol (2016)

Bottom Line: Zika virus (ZIKV), a flavivirus transmitted by Aedes mosquitoes, was identified in 1947 in a sentinel monkey in Uganda, and later on in humans in Nigeria.ZIKV infection was characterized by causing a mild disease presented with fever, headache, rash, arthralgia, and conjunctivitis, with exceptional reports of an association with Guillain-Barre syndrome (GBS) and microcephaly.Clarifying such worrisome relationships is, thus, a current unavoidable goal.

View Article: PubMed Central - PubMed

Affiliation: Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria Madrid, Spain.

ABSTRACT
Since the beginning of this century, humanity has been facing a new emerging, or re-emerging, virus threat almost every year: West Nile, Influenza A, avian flu, dengue, Chikungunya, SARS, MERS, Ebola, and now Zika, the latest newcomer. Zika virus (ZIKV), a flavivirus transmitted by Aedes mosquitoes, was identified in 1947 in a sentinel monkey in Uganda, and later on in humans in Nigeria. The virus was mainly confined to the African continent until it was detected in south-east Asia the 1980's, then in the Micronesia in 2007 and, more recently in the Americas in 2014, where it has displayed an explosive spread, as advised by the World Health Organization, which resulted in the infection of hundreds of thousands of people. ZIKV infection was characterized by causing a mild disease presented with fever, headache, rash, arthralgia, and conjunctivitis, with exceptional reports of an association with Guillain-Barre syndrome (GBS) and microcephaly. However, since the end of 2015, an increase in the number of GBS associated cases and an astonishing number of microcephaly in fetus and new-borns in Brazil have been related to ZIKV infection, raising serious worldwide public health concerns. Clarifying such worrisome relationships is, thus, a current unavoidable goal. Here, we extensively review what is currently known about ZIKV, from molecular biology, transmission routes, ecology, and epidemiology, to clinical manifestations, pathogenesis, diagnosis, prophylaxis, and public health.

No MeSH data available.


Related in: MedlinePlus

Schematic view of Zika virus (ZIKV) genome organization. The open reading frame (ORF) (boxes) that encodes structural and non-structural proteins is flanked by two untranslated regions (UTR). The proportion of each region was calculated from the ZIKV MR766 sequence available at GenBank (NC_012532.1). Scale bar: 1 kb.
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Figure 1: Schematic view of Zika virus (ZIKV) genome organization. The open reading frame (ORF) (boxes) that encodes structural and non-structural proteins is flanked by two untranslated regions (UTR). The proportion of each region was calculated from the ZIKV MR766 sequence available at GenBank (NC_012532.1). Scale bar: 1 kb.

Mentions: The flavivirus genome is constituted by a single-stranded RNA molecule of positive polarity that, in a similar manner to cellular mRNAs, includes a cap structure at its 5′ end (Dong et al., 2014). Proper methylation of this structure is important not only for efficient translation of viral genome, but also for evasion of immune response (Daffis et al., 2010). The sequence of the prototype strain of ZIKV MR766, which corresponds to a passaged virus derived from the initial ZIKV isolated by intracerebral inoculation of the serum of the febrile monkey (Rhesus 766) into mice in 1947 (Dick, 1952; Dick et al., 1952), revealed that the ZIKV genome was 10794 nucleotides in length (Kuno and Chang, 2007). The genome contains a single open reading frame (ORF) that encodes a polyprotein of about 3400 amino acids (Figure 1) that is expected to be cleaved into the mature viral proteins (see next section for polyprotein processing). The single ORF is flanked by two untraslated regions (UTR) located at the 5′ and 3′ ends of the genome, which in the prototype ZIKV MR766 are of 106 and 428 nucleotides in length, respectively (Kuno and Chang, 2007). Remarkably, and in contrast to cellular mRNAs, ZIKV genome lacks a 3′ poly(A) tract and ends with CUOH in a similar manner to the other flaviviruses. Subsequent studies have confirmed that this basic organization is shared among other isolates of ZIKV, although differences in length and nucleotide sequence have been documented among different isolates, even among ZIKV MR766 isolates with different passage history (Lanciotti et al., 2008; Haddow et al., 2012; Baronti et al., 2014; Berthet et al., 2014). The cyclization of flavivirus genome between 5′ and 3′ terminal regions, which is important for the functionality of the genome, is mediated by the interaction of complementary sequences located with genome regions termed conserved sequences (CSs). These CS (CS1 to CS3) are also present in the ZIKV genome, suggesting that has the potential for cyclization. Nevertheless, it has to be remarked that the organization of the CS in the 3′end of ZIKV is different from that of other mosquito-borne flaviviruses (Kuno and Chang, 2007).


Zika Virus: the Latest Newcomer.

Saiz JC, Vázquez-Calvo Á, Blázquez AB, Merino-Ramos T, Escribano-Romero E, Martín-Acebes MA - Front Microbiol (2016)

Schematic view of Zika virus (ZIKV) genome organization. The open reading frame (ORF) (boxes) that encodes structural and non-structural proteins is flanked by two untranslated regions (UTR). The proportion of each region was calculated from the ZIKV MR766 sequence available at GenBank (NC_012532.1). Scale bar: 1 kb.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835484&req=5

Figure 1: Schematic view of Zika virus (ZIKV) genome organization. The open reading frame (ORF) (boxes) that encodes structural and non-structural proteins is flanked by two untranslated regions (UTR). The proportion of each region was calculated from the ZIKV MR766 sequence available at GenBank (NC_012532.1). Scale bar: 1 kb.
Mentions: The flavivirus genome is constituted by a single-stranded RNA molecule of positive polarity that, in a similar manner to cellular mRNAs, includes a cap structure at its 5′ end (Dong et al., 2014). Proper methylation of this structure is important not only for efficient translation of viral genome, but also for evasion of immune response (Daffis et al., 2010). The sequence of the prototype strain of ZIKV MR766, which corresponds to a passaged virus derived from the initial ZIKV isolated by intracerebral inoculation of the serum of the febrile monkey (Rhesus 766) into mice in 1947 (Dick, 1952; Dick et al., 1952), revealed that the ZIKV genome was 10794 nucleotides in length (Kuno and Chang, 2007). The genome contains a single open reading frame (ORF) that encodes a polyprotein of about 3400 amino acids (Figure 1) that is expected to be cleaved into the mature viral proteins (see next section for polyprotein processing). The single ORF is flanked by two untraslated regions (UTR) located at the 5′ and 3′ ends of the genome, which in the prototype ZIKV MR766 are of 106 and 428 nucleotides in length, respectively (Kuno and Chang, 2007). Remarkably, and in contrast to cellular mRNAs, ZIKV genome lacks a 3′ poly(A) tract and ends with CUOH in a similar manner to the other flaviviruses. Subsequent studies have confirmed that this basic organization is shared among other isolates of ZIKV, although differences in length and nucleotide sequence have been documented among different isolates, even among ZIKV MR766 isolates with different passage history (Lanciotti et al., 2008; Haddow et al., 2012; Baronti et al., 2014; Berthet et al., 2014). The cyclization of flavivirus genome between 5′ and 3′ terminal regions, which is important for the functionality of the genome, is mediated by the interaction of complementary sequences located with genome regions termed conserved sequences (CSs). These CS (CS1 to CS3) are also present in the ZIKV genome, suggesting that has the potential for cyclization. Nevertheless, it has to be remarked that the organization of the CS in the 3′end of ZIKV is different from that of other mosquito-borne flaviviruses (Kuno and Chang, 2007).

Bottom Line: Zika virus (ZIKV), a flavivirus transmitted by Aedes mosquitoes, was identified in 1947 in a sentinel monkey in Uganda, and later on in humans in Nigeria.ZIKV infection was characterized by causing a mild disease presented with fever, headache, rash, arthralgia, and conjunctivitis, with exceptional reports of an association with Guillain-Barre syndrome (GBS) and microcephaly.Clarifying such worrisome relationships is, thus, a current unavoidable goal.

View Article: PubMed Central - PubMed

Affiliation: Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria Madrid, Spain.

ABSTRACT
Since the beginning of this century, humanity has been facing a new emerging, or re-emerging, virus threat almost every year: West Nile, Influenza A, avian flu, dengue, Chikungunya, SARS, MERS, Ebola, and now Zika, the latest newcomer. Zika virus (ZIKV), a flavivirus transmitted by Aedes mosquitoes, was identified in 1947 in a sentinel monkey in Uganda, and later on in humans in Nigeria. The virus was mainly confined to the African continent until it was detected in south-east Asia the 1980's, then in the Micronesia in 2007 and, more recently in the Americas in 2014, where it has displayed an explosive spread, as advised by the World Health Organization, which resulted in the infection of hundreds of thousands of people. ZIKV infection was characterized by causing a mild disease presented with fever, headache, rash, arthralgia, and conjunctivitis, with exceptional reports of an association with Guillain-Barre syndrome (GBS) and microcephaly. However, since the end of 2015, an increase in the number of GBS associated cases and an astonishing number of microcephaly in fetus and new-borns in Brazil have been related to ZIKV infection, raising serious worldwide public health concerns. Clarifying such worrisome relationships is, thus, a current unavoidable goal. Here, we extensively review what is currently known about ZIKV, from molecular biology, transmission routes, ecology, and epidemiology, to clinical manifestations, pathogenesis, diagnosis, prophylaxis, and public health.

No MeSH data available.


Related in: MedlinePlus