Poliomielitis, una historia de inicio triste y final feliz / Poliomyelitis, a story with a sad beginning and a happy ending

Se desarrollan los principales elementos históricos en el estudio y la lucha contra la poliomielitis, su aislamiento por Karl Landsteiner en 1909, la primera vacuna con virus muerto (Jonas Salk, 1955), la segunda vacuna con virus vivo atenuado (Albert Sabin, 1961) y la reducción paulatina de la polio en todo el mundo, hasta llegar a menos de 200 casos al año (virus salvaje)(AU)

The main historical events in the study and fight against polio are shown, its isolation by Karl Landsteiner in 1909, the development of the first vaccine with dead virus (Jonas Salk, 1955), the second vaccine with live attenuated virus (Albert Sabin, 1961) and the gradual reduction of polio worldwide, reaching less than 200 cases a year (wild virus)(AU)

Prevalence of neutralizing antibodies against poliovirus 1, 2, and 3 in healthcare professionals aged 20-50 years / Prevalência de anticorpos neutralizantes contra poliovírus 1, 2 e 3 em profissionais de saúde de 20 a 50 anos de idade

ABSTRACT Objective: To describe the prevalence of neutralizing antibodies against poliovirus (PV1, PV2, and PV3) in blood samples of healthcare professionals aged 20 to 50 years. Methods: Health professionals who serve children at Darcy Vargas Children's Hospital and the Department of Pediatrics of Irmandade da Santa Casa de São Paulo. The sample size was calculated at 323 participants. The Mantel-Haenszel chi-square was used to verify differences between groups. The neutralization reaction detected human poliovirus antibodies. For susceptible individuals, vaccination with the inactivated+triple acellular polio vaccine was performed, and neutralizing antibodies were re-dosed after one week. Results: 333 professionals were studied - 92.8% were immune to poliovirus 1, 86.5% to poliovirus 2, and 63.3% to poliovirus 3; 37% had titers less than 1:8 for any serotype, 5;1% had titers below 1:8 for all three. Vaccination with inactivated polio vaccine was performed for susceptible participants, and neutralizing antibodies were dosed after one week, showing increased titers for all polioviruses. Conclusions: Despite the detection of a significant percentage of individuals with low poliovirus antibody titer, the challenge with vaccination demonstrated immune response compatible with poliovirus immunity.

RESUMO Objetivo: Descrever a prevalência de anticorpos neutralizantes contra poliovírus (tipos 1, 2 e 3) em amostra de sangue de profissionais de saúde com idade de 20 a 50 anos. Métodos: Profissionais de saúde que atendem crianças do Hospital Infantil Darcy Vargas e do Departamento de Pediatria da Irmandade da Santa Casa de São Paulo. O tamanho da amostra foi de 323 participantes. Os anticorpos contra poliovírus humanos foram detectados pela reação de neutralização. Para os indivíduos suscetíveis, foram administradas vacina para poliomielite inativada+tríplice e nova dosagem de anticorpos neutralizantes após uma semana. Utilizou-se o teste do qui-quadrado de Mantel-Haenszel para verificar as diferenças entre os grupos. Resultados: Foram estudados 333 profissionais - 92,8% eram imunes ao poliovírus 1; 86,5%, ao poliovírus 2; 63,57%, ao poliovírus 3; 37% apresentaram títulos inferiores a 1:8 para qualquer sorotipo; 5,1% tinham títulos abaixo de 1:8 para os três. Após a vacinação dos suscetíveis, houve elevação dos títulos para todos os poliovírus. Conclusões: Apesar da detecção de percentual significativo de indivíduos com baixo título de anticorpos para poliovírus, o desafio da vacinação demonstrou resposta imune robusta compatível.

A RT-PCR method for selective amplification and phenotypic characterization of all three serotypes of Sabin-related polioviruses from viral mixtures

Outbreaks caused by vaccine-derived polioviruses are challenging the final eradication of paralytic poliomyelitis. Therefore, the surveillance of the acute flaccid paralysis cases based on poliovirus isolation and characterization remains an essential activity. Due to the use of trivalent oral poliovirus vaccine (OPV), mixtures containing more than one serotype of Sabin-related polioviruses are frequently isolated from clinical samples. Because each poliovirus isolate needs to be individually analyzed, we designed polymerase chain reaction primers that can selectively distinguish and amplify a genomic segment of the three Sabin-related poliovirus serotypes present in mixtures, thus, optimizing the diagnosis and providing prompt information to support epidemiologic actions.

Poliomielite e síndrome pós-pólio

A cirurgia, agressiva, por vezes abusiva, em pleno inverno paulistano, predispunha à polioencefalite, à perda da consciência! Não bastante, identificavam-se mais fatores desencadeantes: injeções intramusculares, apendicectomias, insolação, exposição ao frio... A carga dos vírus selvagens em circulação na população era fora do comum. Iceberg, o melhor exemplo para estimativa de sua densidade; a ponta, as ocorrências paralíticas; a base, submersa, a imensidade das formas inaparentes.Denominação paralisia infantil? Impropriedade. Adultos ? populares ou famosos ? padeceram da enfermidade.A raiva muda ? forma clínica paralítica da raiva humana ?, figurava entre opções na discussão de casos. Nada simples distinguir enfermidades com sintomas afins.Trata-se agora de rediscutir a estratégia para assegurar de vez a erradicação.A modalidade atual de queixas,retroativas,é a "síndrome pós-pólio".

Neurological morbidity in vaccine-associated paralytic poliomyelitis in Brazil: from 1989 up to 1995

Trinta casos de poliomielite associada à vacinação oral (Sabin) foram estudados a partir de 4081 notificações de paralisias agudas e flácidas feitas ao Ministério da Saúde no período de 1989 a 1995, com o objetivo de avaliar a gravidade do quadro neurológico. Dezesseis pacientes tiveram monoplegia, 6 paraplegia, 5 tetraplegia, 2 hemiplegia e 1 triplegia. Foram 56% em menores de 1 ano, 56,7% no sexo feminino, 46% dos casos provenientes do nordeste. Em 10 pacientes foi isolado o vírus vacinal P2, em oito o P3 e dois o P1. Os demais tinham associações de mais de um tipo de vírus. Febre antes ou após o período prodrômico e o uso de medicação intramuscular não se relacionaram a maior morbidade. A política antipoliomielite adotada no Brasil levou à erradicação da poliomielite pelo vírus selvagem com um risco mínimo do ponto de vista epidemiológico, porém ainda com custos individuais não desprezíveis.

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 2 polioviruses isolated from vaccine-associated cases in Brazil

Twenty strains of P2/Sabin-related polioviruses isolated in Brazil were analyzed; ten from persistent paralytic poliomyelitis cases, three from suspected polio cases with transient paralysis, and seven from healthy contacts. The serotypes of the viral isolates were identified by the neutralization test with hyperimmune equine sera. The relationship of the isolates to the P2/Sabin strain was demonstrated by molecular hydridization and polymerase chain reaction (PCR). Partial sequencing demonstrated mutations at nucleotide 481 in the 5' noncoding region and at amino acid 143 of the capsid protein VP1 in most of these isolates from accine-associated cases in Brazil. These data support previous studies on the importance of mutations at these attenuated determinants in the establishment of the disease. However, the existence of isolates without mutations at these positions suggests that they are not essential. The results also strengthen the possibility of the participation of a mutation at nucleotide 398 in the establishment of the disease, and suggest that a mutation at nucleotide 491 or 500 may also be involved in this process. The isolates from healthy contacts presented the same mutations as the isolates from vaccine-associated cases with they were in contact. This strengthens the observation that, although mutations in the genome of the P2/Sabin strain are important for the establishment of the disease, host factors are also involved