Limits...
Genetic relatedness of infecting and reinfecting respiratory syncytial virus strains identified in a birth cohort from rural Kenya.

Agoti CN, Mwihuri AG, Sande CJ, Onyango CO, Medley GF, Cane PA, Nokes DJ - J. Infect. Dis. (2012)

Bottom Line: The extent to which this is a consequence of RSV antigenic diversity is unclear.A positive sample separated from a previous positive by ≥14 days was defined as a reinfection a priori.Heterologous group reinfections were observed in 28 episodes, and homologous group reinfections were observed in 25 episodes; 10 involved homologous genotypes, 5 showed no amino acid changes, and 3 were separated by 21-24 days and were potentially persistent infections.

View Article: PubMed Central - PubMed

Affiliation: Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, Kenya. cnyaigoti@kilifi.kemri-wellcome.org

ABSTRACT

Background: Respiratory syncytial virus (RSV) reinfects individuals repeatedly. The extent to which this is a consequence of RSV antigenic diversity is unclear.

Methods: Six-hundred thirty-five children from rural Kenya were closely monitored for RSV infection from birth through 3 consecutive RSV epidemics. RSV infections were identified by immunofluorescence testing of nasal washing samples collected during acute respiratory illnesses, typed into group A and B, and sequenced in the attachment (G) protein. A positive sample separated from a previous positive by ≥14 days was defined as a reinfection a priori.

Results: Phylogenetic analysis was undertaken for 325 (80%) of 409 identified infections, including 53 (64%) of 83 reinfections. Heterologous group reinfections were observed in 28 episodes, and homologous group reinfections were observed in 25 episodes; 10 involved homologous genotypes, 5 showed no amino acid changes, and 3 were separated by 21-24 days and were potentially persistent infections. The temporal distribution of genotypes among reinfections did not differ from that of single infections.

Conclusions: The vast majority of infection and reinfection pairs differed by group, genotype, or G amino acid sequence (ie, comprised distinct viruses). The extent to which this is a consequence of immune memory of infection history or prevalent diversity remains unclear.

Show MeSH

Related in: MedlinePlus

The time course of 53 RSV infections in the 52 children who had repeat infection. The different subplots represent the group reinfection patterns observed. In the subplots, the dotted portions of the black horizontal straight lines represent the time from birth to the first positive sample of a reinfected participant. Each symbol between the continuous portions of the horizontal line represents a positive sample for which genotyping was completed: empty red circle, GA2; a red x symbol, GA5; empty blue triangle, SAB1 and filled blue square, BA. The continuous red curve and the dotted blue curve represent the monthly trends in the number of RSV A and RSV B cases detected, respectively, in the whole cohort, shown by the secondary y-axis.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3475639&req=5

JIS570F1: The time course of 53 RSV infections in the 52 children who had repeat infection. The different subplots represent the group reinfection patterns observed. In the subplots, the dotted portions of the black horizontal straight lines represent the time from birth to the first positive sample of a reinfected participant. Each symbol between the continuous portions of the horizontal line represents a positive sample for which genotyping was completed: empty red circle, GA2; a red x symbol, GA5; empty blue triangle, SAB1 and filled blue square, BA. The continuous red curve and the dotted blue curve represent the monthly trends in the number of RSV A and RSV B cases detected, respectively, in the whole cohort, shown by the secondary y-axis.

Mentions: The monthly number of RSV A and B cases that were observed over the entire study period is shown in Figure 1. Four epidemic seasons were observed. Groups A and B varied in predominance in succeeding epidemics, resulting in a pattern of A, A/B, A/B, and B.Figure 1.


Genetic relatedness of infecting and reinfecting respiratory syncytial virus strains identified in a birth cohort from rural Kenya.

Agoti CN, Mwihuri AG, Sande CJ, Onyango CO, Medley GF, Cane PA, Nokes DJ - J. Infect. Dis. (2012)

The time course of 53 RSV infections in the 52 children who had repeat infection. The different subplots represent the group reinfection patterns observed. In the subplots, the dotted portions of the black horizontal straight lines represent the time from birth to the first positive sample of a reinfected participant. Each symbol between the continuous portions of the horizontal line represents a positive sample for which genotyping was completed: empty red circle, GA2; a red x symbol, GA5; empty blue triangle, SAB1 and filled blue square, BA. The continuous red curve and the dotted blue curve represent the monthly trends in the number of RSV A and RSV B cases detected, respectively, in the whole cohort, shown by the secondary y-axis.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3475639&req=5

JIS570F1: The time course of 53 RSV infections in the 52 children who had repeat infection. The different subplots represent the group reinfection patterns observed. In the subplots, the dotted portions of the black horizontal straight lines represent the time from birth to the first positive sample of a reinfected participant. Each symbol between the continuous portions of the horizontal line represents a positive sample for which genotyping was completed: empty red circle, GA2; a red x symbol, GA5; empty blue triangle, SAB1 and filled blue square, BA. The continuous red curve and the dotted blue curve represent the monthly trends in the number of RSV A and RSV B cases detected, respectively, in the whole cohort, shown by the secondary y-axis.
Mentions: The monthly number of RSV A and B cases that were observed over the entire study period is shown in Figure 1. Four epidemic seasons were observed. Groups A and B varied in predominance in succeeding epidemics, resulting in a pattern of A, A/B, A/B, and B.Figure 1.

Bottom Line: The extent to which this is a consequence of RSV antigenic diversity is unclear.A positive sample separated from a previous positive by ≥14 days was defined as a reinfection a priori.Heterologous group reinfections were observed in 28 episodes, and homologous group reinfections were observed in 25 episodes; 10 involved homologous genotypes, 5 showed no amino acid changes, and 3 were separated by 21-24 days and were potentially persistent infections.

View Article: PubMed Central - PubMed

Affiliation: Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, Kenya. cnyaigoti@kilifi.kemri-wellcome.org

ABSTRACT

Background: Respiratory syncytial virus (RSV) reinfects individuals repeatedly. The extent to which this is a consequence of RSV antigenic diversity is unclear.

Methods: Six-hundred thirty-five children from rural Kenya were closely monitored for RSV infection from birth through 3 consecutive RSV epidemics. RSV infections were identified by immunofluorescence testing of nasal washing samples collected during acute respiratory illnesses, typed into group A and B, and sequenced in the attachment (G) protein. A positive sample separated from a previous positive by ≥14 days was defined as a reinfection a priori.

Results: Phylogenetic analysis was undertaken for 325 (80%) of 409 identified infections, including 53 (64%) of 83 reinfections. Heterologous group reinfections were observed in 28 episodes, and homologous group reinfections were observed in 25 episodes; 10 involved homologous genotypes, 5 showed no amino acid changes, and 3 were separated by 21-24 days and were potentially persistent infections. The temporal distribution of genotypes among reinfections did not differ from that of single infections.

Conclusions: The vast majority of infection and reinfection pairs differed by group, genotype, or G amino acid sequence (ie, comprised distinct viruses). The extent to which this is a consequence of immune memory of infection history or prevalent diversity remains unclear.

Show MeSH
Related in: MedlinePlus