Yellow Fever
Páginas: 2 (445 palabras)
Publicado: 27 de septiembre de 2011
-------------------------------------------------
Yellow fever
-------------------------------------------------
Signs and symptoms
Yellow fever begins after an incubation period of three to sixdays.[8] Most cases only cause a mild infection with fever, headache, chills, back pain, loss of appetite, nausea and vomiting.[9] In these cases the infection lasts only three to four days. Infifteen percent of cases, however, sufferers enter a second, toxic phase of the disease with recurring fever, this time accompanied by jaundice due toliver damage, as well as abdominal pain. Bleeding in themouth, the eyes and in the gastrointestinal tract can cause vomitus containing blood (giving the name black vomit).[10] The toxic phase is fatal in approximately 20% of cases, making the overallfatality rate for the disease 3% (15% * 20%).[11]
Surviving the infection causes life-long immunity [12] and normally there is no permanent organ damage.[13]-------------------------------------------------
Cause
Yellow fever is caused by the yellow fever virus, a 40 to 50 nmwide enveloped RNA virus belonging to the family Flaviviridae. The positive sense single-stranded RNA is approximately11,000 nucleotides long and has a single open reading frameencoding a polyprotein. Host proteases cut this polyprotein into three structural (C, prM, E) and seven non-structural proteins (NS1, NS2A, NS2B,NS3, NS4A, NS4B, NS5); the enumeration corresponds to the arrangement of the protein coding genes in the genome.[14] The viruses infect amongst others monocytes, macrophages and dendritic cells. Theyattach to the cell surface via specificreceptors and are taken up by an endosomal vesicle. Inside the endosome, the decreased pHinduces the fusion of the endosomal membrane with the virus envelope.Thus, the capsid reaches the cytosol, decays and releases the genome. Receptor binding as well as membrane fusion arecatalyzed by the protein E, which changes its conformation at low pH, which causes...
Yellow fever
-------------------------------------------------
Signs and symptoms
Yellow fever begins after an incubation period of three to sixdays.[8] Most cases only cause a mild infection with fever, headache, chills, back pain, loss of appetite, nausea and vomiting.[9] In these cases the infection lasts only three to four days. Infifteen percent of cases, however, sufferers enter a second, toxic phase of the disease with recurring fever, this time accompanied by jaundice due toliver damage, as well as abdominal pain. Bleeding in themouth, the eyes and in the gastrointestinal tract can cause vomitus containing blood (giving the name black vomit).[10] The toxic phase is fatal in approximately 20% of cases, making the overallfatality rate for the disease 3% (15% * 20%).[11]
Surviving the infection causes life-long immunity [12] and normally there is no permanent organ damage.[13]-------------------------------------------------
Cause
Yellow fever is caused by the yellow fever virus, a 40 to 50 nmwide enveloped RNA virus belonging to the family Flaviviridae. The positive sense single-stranded RNA is approximately11,000 nucleotides long and has a single open reading frameencoding a polyprotein. Host proteases cut this polyprotein into three structural (C, prM, E) and seven non-structural proteins (NS1, NS2A, NS2B,NS3, NS4A, NS4B, NS5); the enumeration corresponds to the arrangement of the protein coding genes in the genome.[14] The viruses infect amongst others monocytes, macrophages and dendritic cells. Theyattach to the cell surface via specificreceptors and are taken up by an endosomal vesicle. Inside the endosome, the decreased pHinduces the fusion of the endosomal membrane with the virus envelope.Thus, the capsid reaches the cytosol, decays and releases the genome. Receptor binding as well as membrane fusion arecatalyzed by the protein E, which changes its conformation at low pH, which causes...
Leer documento completo
Regístrate para leer el documento completo.