Genetic characterization of dengue virus type 3 isolates in the State of Rio de Janeiro, 2001

The genetic characterization of dengue virus type 3 (DEN-3) strains isolated from autochthonous cases in the State of Rio de Janeiro, Brazil, in 2001 is presented. Restriction site-specific (RSS)-PCR performed on 22 strains classified the Brazilian DEN-3 viruses as subtype C, a subtype that contains viruses from Sri Lanka, India, Africa and recent isolates from Central America. Nucleic acid sequencing (positions 278 to 2550) of one DEN-3 strain confirmed the origin of these strains, since genotype III - classified by sequencing - and RSS-PCR subtype C are correlated. This genetic subtype has been associated with hemorrhagic dengue epidemics and the information provided here could be useful to implement appropriate prevention and control measures

Dengue virus infection of the central nervous system (CNS): a case report from Brazil.

Dengue infection that is accompanied by unusual complications has been described in Brazil. We report on the presence of dengue virus in the central nervous system (CNS) of a patient who died in 1998 in Rio Grande do Norte, northeast Brazil. DEN-2 viruses were isolated from the brain liver, and lymphnode tissue of a 67-year-old man whose signs and symptoms were those of dengue infection and a secondary immune response. A postmortem revealed nose bleeds a liver that was brownish with yellow areas, and pulmonary and cerebrae congestion. Immunoperoxidase staining showed a dengue antigen-specific positive reaction in the gray matter cells of the cerebrall cortex; a granular citoplasmatic reaction was seen in the neurons. Dengue infection should always be considered as a cause encephalitis in tropical countries, especially in those where the disease is endemic.

Temporal association between the isolation of Sabin-related poliovirus vaccine strains and the Guillain-Barre syndrome

Thirty eigth paralysis classified as Guillain-Barre syndrome (GBS) in Brazil were analysed. In all these cases Sabin-related poliovirus vaccine strains were isolated. In most of the cases the last vaccine dose was given months or years before the onset of GBS, suggesting a persistent infection or transmission of the Sabin-related strains to the patients...

Poliovirus type 1 isolated from a vaccine-associated case of paralytic poliomyelitis in Brazil

This study reports a type 1 poliovirus strain isolated in Brazil from a case classified as vaccine-associated paralytic poliomyelitis (VAPP). After serotyping of the viral isolate with hyperimmune equine sera, PCR and molecular hybridization techniques characterized the strain as P1/Sabin-derived. The isolate was partially sequenced to identify mutations at nucleotides 480, 525 and 6203, which are important for reversion of the P1/Sabin strain to neurovirulence. In a recent study, a P1/ Sabin-derived strain isolated from the central nervous system of a VAPP case did not mutate at these positions, but maintained 480-G and 525-U (and 6203-C), suggesting that these mutations are not essential for the occurrence of disease (Georgescu et al., (1994), Journal of Virology, 68: 8089-8101). Although the Brazilian strain also maintained 480-G and 525-U (and 6203-C) and was isolated from the stool, the possibility that this isolate invaded the central nervous system after replicating in the gut, causing the paralysis, cannot be ruled out. This is the first report of a type I VAPP case in Brazil, although some cases caused by type 2 and type 3 strains have been described.

Genomic characterization of type 3 polioviruses isolated from vaccine-associated poliomyelitis cases in Brazil

Eight strains of P3/Sabin-related polioviruses were analyzed; four from persistent paralytic poliomyelitis cases classified as vaccine associated, one from a transient paralysis case classified as transverse myelitis, one from a transient paralysis case classified as Guillain-Barr'e syndrome, one from a transient facial paralysis case, and one from a healthy vaccine. The serotypes of the viral isolates were identified by the neutralization test with hyperimmune equine sera and the relationship of the isolates with the P3/Sabin strain was demonstrated by molecular hybridization of the viral RNA of the isolates with a P3/Sabin-specific probe. The P3/Sabin relationship was confirmed by PCR, using a pair of specific primers for P3/Sabin-related isolates. The available data indicate that a U C mutation at nucleotide 472 in the 5' noncoding region of the genome of the type 3 Sabin strain increases the neurovirulence of this strain and this mutation was observed in all type 3 isolates from vaccine-associated cases. These eight P3/Sabin-related isolates were partially sequenced in the 5" noncoding region and seven presented a U C mutation at nucleotide 472, except the isolate from a transient paralysis case classfied as transverse myelitis, that maintained a U at nucleotide 472. Although this virus maintaining U at nucleotide 472 may not be the etiological agent of the disease, the possibility that virus was the causative agent of the disease could not be ruled out

Intratypic differentiation of polioviruses isolated from suspected cases of poliomyelitis in Brazil during the period of 1990 to 1993

This study analyzed 3129 fecal samples derived from 1626 patients with sudden onset acute flaccid paralysis clinically compatible with poliomyelitis. The samples were collected in the period ranging from January 1990 to September 1993 in all regions of Brazil. Among the 1626 cases studied, 196 had isolation of poliovirus. Nevertheless, it was observed that some factors influenced the isolation rate and the intratypic characterization of these polioviruses. No cases of acute flaccid paralysis has been found to be etiologically related with wild polioviruses.