RESUMEN
In this review, we discuss the possibility that the glycosylation of West Nile (WN) virus E-protein may be associated with enhanced pathogenicity and higher replication of WN virus. The results indicate that E-protein glycosylation allows the virus to multiply in a heat-stable manner and therefore, has a critical role in enhanced viremic levels and virulence of WN virus in young-chick infection model. The effect of the glycosylation of the E protein on the pathogenicity of WN virus in young chicks was further investigated. The results indicate that glycosylation of the WN virus E protein is important for viral multiplication in peripheral organs and that it is associated with the strong pathogenicity of WN virus in birds. The micro-focus reduction neutralization test (FRNT) in which a large number of serum samples can be handled at once with a small volume (15 µL) of serum was useful for differential diagnosis between Japanese encephalitis and WN virus infections in infected chicks. Serological investigation was performed among wild birds in the Far Eastern region of Russia using the FRNT. Antibodies specific to WN virus were detected in 21 samples of resident and migratory birds out of 145 wild bird samples in the region.
Asunto(s)
Enfermedades de las Aves/epidemiología , Proteínas del Envoltorio Viral/metabolismo , Fiebre del Nilo Occidental/epidemiología , Virus del Nilo Occidental/patogenicidad , Animales , Enfermedades de las Aves/diagnóstico , Enfermedades de las Aves/virología , Aves , Glicosilación , Estudios Seroepidemiológicos , Siberia/epidemiología , Fiebre del Nilo Occidental/diagnóstico , Fiebre del Nilo Occidental/virología , Virus del Nilo Occidental/aislamiento & purificación , Virus del Nilo Occidental/fisiologíaRESUMEN
A variety of hantaviruses are harbored by rodents in North and South America, some of which can cause hantavirus pulmonary syndrome. To obtain greater evolutionary insight into hantaviruses in the Americas, a total of 211 rodents were captured in the Mexican states of Guerrero and Morelos in 2006. Anti-hantavirus antibodies were detected in 27 of 211 serum samples (12.8%) by ELISA. The distribution of seropositive rodents was: 17 Peromyscus beatae, 1 Megadontomys thomasi, 1 Neotoma picta, 6 Reithrodontomys sumichrasti, and 2 Reithrodontomys megalotis. The hantavirus small (S), medium (M), and large (L) genome segments from P. beatae, R. sumichrasti, and R. megalotis were amplified and the sequences covering the open reading frames were determined. The hantaviruses from P. beatae, R. sumichrasti, and R. megalotis were provisionally designated Montano (MTN), Carrizal (CAR), and Huitzilac (HUI), respectively. The M segment amino acid identities among the Mexican hantaviruses were 80.8-93.0%. When these M segments were compared to those of known hantaviruses, MTN virus was most closely related to Limestone Canyon (LSC) virus (88.9% amino acid identity), while the CAR and HUI viruses were most closely related to El Moro Canyon (ELMC) virus (90-91% identity). Phylogenetic analysis revealed that the MTN, CAR, and HUI viruses occupy a monophyletic clade with the LSC, ELMC, and Rio Segundo viruses, which are harbored by Peromyscus boylii, R. megalotis, and Reithrodontomys mexicanus, respectively. The data obtained in this study provide important information for understanding the evolution of hantaviruses in the Americas.
Asunto(s)
Arvicolinae/virología , Variación Genética , Orthohantavirus/clasificación , Orthohantavirus/aislamiento & purificación , Animales , Anticuerpos Antivirales/sangre , Análisis por Conglomerados , Ensayo de Inmunoadsorción Enzimática , Orthohantavirus/genética , México , Datos de Secuencia Molecular , Técnicas de Amplificación de Ácido Nucleico , Filogeografía , ARN Viral/genética , Análisis de Secuencia de ADN , Homología de Secuencia de AminoácidoRESUMEN
Birds are important for the transmission of West Nile virus (WNV) in nature, but the significance of the potential N-linked glycosylation at position 154 in the WNV envelope (E) protein with regard to viral replication in young chickens has not been assessed. In this study, the effect of glycosylation of the WNV E protein on viral pathogenicity in birds was investigated using young domestic chicks. A higher viral load was detected in the blood and the peripheral organs, particularly the hearts, of 2-day-old chicks inoculated with a glycosylated WNV variant compared to those inoculated with the nonglycosylated variant. There was no significant difference in the neutralizing antibody titers and cytokine expression profiles in chickens inoculated with the glycosylated and the nonglycosylated WNV variants. In contrast, no virus w as detected in the blood and the tissues of 3-wk-old chicks, although the host immune response was induced to similar levels as in the 2-day-old chicks. These data indicate the utility of young domestic chicks as an animal model of WNV infection; they also indicate that glycosylation of the E protein of WNV enhances multiplication in the blood and peripheral organs, which is associated with the strong pathogenicity of WNV in birds.