Fig 1.
Study flow chart.
Fig 2.
Dot plot of chikungunya virus (CHIKV) plaque reduction neutralization test (PRNT) titers at enrollment and 12 months in per-protocol subjects.
All 19 symptomatic and 87 subclinical CHIKV infections had enrollment PRNT titer <10 and 12-month titers ranging from 229 to 2,030 in symptomatic infections and 64 to 3,347 in subclinical infections; 239 subjects had positive titers at enrollment ranging from 10 to 1,785; and 505 subjects had negative titers at both enrollment and 12 months.
Fig 3.
Phylogenetic tree showing five chikungunya viruses (CHIKVs) characterized in the study.
The tree was constructed by neighbor-joining methods (1,000 bootstrap replications) using envelope protein-1 (E1) nucleotide sequences (1,320 bp) of 46 CHIKV strains; the five from the study are designated in bold. Bootstrap support values are shown for major nodes. Scale bar indicates nucleotide substitutions per site. Genotypes are indicated on the right. The sequences were named according to virus/country/strain/year of collection or isolation. GenBank accession numbers are shown in parentheses.
Table 1.
Description of cohort subjects.
Table 2.
Incidence of CHIKV infections and seroprevalence of CHIKV PRNT in different age groups.a
Table 3.
Incidence of CHIKV infections among individuals with negative baseline CHIKV PRNT in different age groups.a
Table 4.
Clinical presentation of symptomatic CHIKV infections.a
Table 5.
Relationship between symptomatic CHIKV infection and baseline enrollment CHIKV PRNT status.a