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Some characteristics of poliovirus strains isolated in Uganda between 1966 and 1971
Abstract:
Sixty-five poliovirus strains were investigated in genetic marker tests in order to obtain information on the characteristics of polioviruses circulating in Uganda where, owing to the insufficient use of live poliovirus vaccine, poliomyelitis remained a serious public health problem. Of the type 1 strains predominant in both epidemic and non-epidemic years, 29 were studied for their antigenic fine structure. Based on their intratypic character, these strains proved to represent six different antigenic variants. Three of these variants were predominant during certain periods; the first variant was present in 1966 and 1968, the second in 1967, and the third from 1969 to the end of observation period. Four strains from Kuwait and three from Ghana isolated in 1969 and 1970 showed an antigenic structure identical to that of the strains predominant in Uganda in these years. Some strains proved to be of vaccine origin. Twenty-nine type 1 and 24 type 2 strains showed a great variety of characteristics when studied in d, od, and rct/40 marker tests. There was no indication that the distribution of strains according to their in vitro markers would have been different in epidemic and non-epidemic years, or that any particular combination of markers would have been more common among strains isolated from paralytic patients than among those from non-paralytic patients. Nine of 12 type 3 strains had the rct/40(+) marker.
Insights
Poliovirus strains in Uganda showed diverse genetic markers and antigenic variants, impacting public health due to insufficient vaccination. Some strains were vaccine-derived, highlighting the need for effective poliovirus control strategies.
Area of Science:
- Virology
- Public Health
- Epidemiology
Background:
- Poliomyelitis remains a significant public health concern in Uganda, linked to inadequate live poliovirus vaccine coverage.
- Understanding circulating poliovirus strains is crucial for effective disease control and prevention strategies.
Purpose of the Study:
- To characterize the genetic markers and antigenic properties of poliovirus strains circulating in Uganda.
- To investigate potential correlations between viral characteristics, epidemic patterns, and disease severity.
Main Methods:
- Genetic marker tests (d, od, rct/40) were performed on 65 poliovirus strains.
- Antigenic fine structure analysis was conducted on 29 type 1 strains.
- Viral strains from Uganda, Kuwait, and Ghana were compared.
Main Results:
- Six distinct antigenic variants of type 1 poliovirus were identified, with temporal predominance of three variants.
- Strains from Ghana and Kuwait exhibited similar antigenic structures to those prevalent in Uganda.
- A variety of characteristics were observed in type 1 and type 2 strains across different in vitro marker tests.
- No clear association was found between in vitro markers and epidemic years or disease severity.
- Some investigated strains were identified as being of vaccine origin.
Conclusions:
- Circulating polioviruses in Uganda exhibit significant antigenic diversity and genetic variability.
- The presence of vaccine-derived strains warrants continued surveillance and vaccination efforts.
- Further research is needed to understand the epidemiological implications of these viral characteristics.