Resolution of the Pathways of Poliovirus Type 1 Transmission during an Outbreak

Abstract

An outbreak of poliomyelitis with 20 cases occurred in Israel, Gaza, and the West Bank from October 1987 to October 1988. The wild type 1 poliovirus associated with the outbreak was most closely related to viruses found in the Nile Delta. The epidemiologic links among patients involved in the outbreak and patients with community-acquired infections during the outbreak were inferred from the evolutionary relationships among isolates of the outbreak virus. Complete VP1 sequences (906 nucleotides) were determined for 12 clinical and 4 sewage isolates. A total of 58 nucleotide differences were found among the 16 isolates; 74% of all substitutions were synonymous third-position transitions. An evolutionary tree, representing both the pathways of VP1 sequence evolution and the inferred chains of virus transmission during the outbreak, was constructed under the assumption that each substitution had occurred only once. The combined epidemiologic and molecular data suggest that a single founder strain was introduced into Israel from the vicinity of Gaza in the fall of 1987. Poliovirus circulation was apparently localized to southern communities during the winter and spread north by the following summer into the Hadera subdistrict of Israel, where it radiated via multiple chains of transmission into other communities in northern Israel and the West Bank. The close sequence matches (>99%) between clinical and sewage isolates from the same communities confirm the utility of environmental sampling as a tool for monitoring wild poliovirus circulation.

Molecular and Antigenic Characterization of a Highly Evolved Derivative of the Type 2 Oral Poliovaccine Strain Isolated from Sewage in Israel

“…Because isolate 4568-1 was initially recognized as an antigenic variant when tested with highly specific animal sera, we sought to determine whether the antigenic differences between 4568-1 and Sabin 2 would also be evident when they were tested against human immune sera. Fifty serum samples, collected from a cohort of 15-year-old high school students who had received at least three OPV doses in early childhood and a booster dose during the 1988 Israeli outbreak (22), were tested for titers of neutralizing antibodies to 4568-1, Sabin 2, and MEF-1 (the type 2 IPV strain). While all 50 serum samples contained protective levels of neutralizing antibody to all three type 2 polioviruses, the geometric mean titers (GMT) of antibody to 4568-1 were sig- on July 5, 2020 by guest http://jcm.asm.org/ nificantly lower (GMT, 47) than those to Sabin 2 (GMT, 162) or MEF-1 (GMT, 108).…”

“…Sequence analysis. Sequence analysis of the capsid coding region (pP1, a 1,100-nucleotide [nt] reverse transcription-PCR [RT-PCR]-amplified segment which includes the entire VP1 gene and the VP1/2A junction) and 385 nt of the 5Ј untranslated region (5Ј-UTR) was carried out as previously described (11,22,28). The RT-PCR product was purified directly from the RT-PCR mixture and sequenced using the ABI PRISM Dye Deoxy Terminator Cycle Sequencing Kit (Applied Biosystems, Foster City, Calif.).…”

“…Routine environmental surveillance of wastewater for polioviruses was initiated in Israel and the Palestinian Authority following the last poliomyelitis outbreak in 1988 (14,22). This approach has proven to be a powerful method to detect wild poliovirus circulation in communities where no poliomyelitis cases have been reported (14).…”

Polio eradication: the OPV paradox

“…Molecular clock data may be used to estimate the dates of the common ancestors to wild [50,55] and vaccine-derived [39,44,45] poliovirus isolates. The detection of common recombination breakpoints among related viruses provide additional support for phylogenetic relationships inferred from the pattern of nucleotide substitutions [39,50].…”

Assessing the stability of polio eradication after the withdrawal of oral polio vaccine

“…A recent model estimated that the effective reproduction 560 number of WPV among children in the Bedouin community in which transmission was most 561 common was 1.8 [15]; the corresponding reproduction numbers for the Sabin strains, assuming our 562 model of infectivity, are 0.4 and below. Our interpretation is that Israel in 2013 was an example of a 563 moderate transmission rate setting where WPV can persist despite comprehensive IPV vaccination 564 but the Sabin strains cannot [116][117][118].…”