title: Three cases of paralytic poliomyelitis associated with type 3 vaccine poliovirus strains in Bulgaria.
abstract: Oral poliovirus vaccine (OPV) can cause, in extremely rare cases vaccine-associated paralytic poliomyelitis in recipients, or contacts of vaccinees. Three cases of vaccine-associated paralytic poliomyelitis (two contacts and one recipient) occurred in the Bourgas region of Bulgaria in the spring of 2006. The first two cases, notified as acute flaccid paralysis, were 55 days old unvaccinated twin brothers, having been in contact with vaccinees. The third case concerned a 4-month-old infant who had received the first OPV dose 37 days prior to the onset of illness. Complete clinical, epidemiological, virological, serological and molecular investigations of the children with paralysis and their contacts were undertaken. In all the three cases type 3 polioviruses were isolated from fecal samples and characterized as Sabin-like poliovirus strains. Type 3 polioviruses isolated from the twin brothers demonstrated by sequence analysis U-to-C back mutation at nt 472 of the 5' UTR, known to correlate with neurovirulence, and mutation in the VP1 region. Type 3 poliovirus isolated from the third child demonstrated in the 3D sequenced region a recombination with Sabin type 1 poliovirus. In the latter region, three silent mutations and one, resulting in amino acid substitution, were also observed. The clinical, epidemiological and virological data and the neurological sequelae observed 60 days following the onset of paralysis, confirmed the diagnosis of vaccine-associated paralytic poliomyelitis in all the three patients.
authors.affiliation: National Centre of Infectious and Parasitic Diseases, Sofia, Bulgaria. polionl_nk@abv.bg
authors.forename: Neli
authors.initials: N
authors.lastname: Korsun
authors.forename: Mira
authors.initials: M
authors.lastname: Kojouharova
authors.forename: Nadezhda
authors.initials: N
authors.lastname: Vladimirova
authors.forename: Lucia
authors.initials: L
authors.lastname: Fiore
authors.forename: Ivan
authors.initials: I
authors.lastname: Litvinenko
authors.forename: Gabriele
authors.initials: G
authors.lastname: Buttinelli
authors.forename: Stefano
authors.initials: S
authors.lastname: Fiore
authors.forename: Violeta
authors.initials: V
authors.lastname: Voynova-Georgieva
authors.forename: Zornitsa
authors.initials: Z
authors.lastname: Mladenova
authors.forename: Daniela
authors.initials: D
authors.lastname: Georgieva
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D000328:Adult; D002031:Bulgaria; D002648:Child; D002675:Child, Preschool; D005243:Feces / Q000821:virology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D017354:Point Mutation; D011051:Poliomyelitis / Q000473:pathology / Q000821:virology*; D017955:Poliovirus / Q000235:genetics / Q000302:isolation & purification*; D023321:Poliovirus Vaccines / Q000009:adverse effects*; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA
chemical_list: D020121:5' Untranslated Regions; D023321:Poliovirus Vaccines