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The molecular epidemiology of type 1 poliovirus in Central African Republic
J M Morvan1, C Chezzi, I Gouandjika
1WHO Regional Center for Poliomyelitis, Institut Pasteur de Bangui, Central African Republic. morvan@intnet.cf
Insights
Wild poliovirus type 1 caused more acute flaccid paralysis cases in Bangui, CAR. Genetic analysis revealed three genotypes co-circulating and linked to strains in neighboring African countries, necessitating a multinational eradication strategy.
Area of Science:
- Virology
- Epidemiology
- Public Health
Background:
- An increase in acute flaccid paralysis (AFP) cases linked to wild-type 1 poliovirus was observed in Bangui, Central African Republic (CAR) during 1993-1994.
- Poliovirus circulation poses a significant public health threat, particularly in regions with vulnerable populations.
Purpose of the Study:
- To genetically characterize poliovirus isolates from Bangui, CAR, between 1993 and 1994.
- To understand the genetic relationships and origins of circulating poliovirus strains in the region.
- To inform strategies for poliomyelitis eradication.
Main Methods:
- Analysis of 33 poliovirus isolates using restriction fragment length polymorphism (RFLP).
- Sequencing of the VP1/2A junction region (150 nucleotides) of the viral genome.
- Comparison of viral sequences with isolates from neighboring and endemic countries.
Main Results:
- Two distinct poliovirus genotypes (A and B) were co-circulating in 1993.
- A third genotype (C) was identified in 1994.
- Genotype A showed 90.7% identity to strains from Egypt; Genotype B showed 96.7% identity to strains from Kenya, Sudan, and Egypt; Genotype C showed 89.0% identity to strains from western and southern Africa.
Conclusions:
- The genetic diversity and linkage of CAR poliovirus isolates with strains from neighboring countries indicate intense, cross-border virus transmission.
- Poliomyelitis eradication in CAR requires a coordinated multinational strategy to halt poliovirus circulation across Africa.
- Transnational cooperation is essential for controlling and eliminating infectious diseases like poliomyelitis.
Abstract:
An increase in the incidence of acute flaccid paralysis cases associated with wild-type 1 poliovirus occurred in children in the city of Bangui, Central African Republic (CAR), in 1993 and 1994. Genetic relationships of 33 isolates were analysed by restriction fragment length polymorphism and by sequencing the VP1/2A junction region (150 nucleotides) of the viral genome. Two distinct genotypes, A and B, were co-circulating in 1993, while in 1994 only a third genotype, C, was observed. Comparison of the sequences found, with those of the sequences from isolates from neighbouring and other endemic countries revealed that genotype A isolates were related to strains from Egypt (90.7% identity), genotype B isolates to strains from Kenya (96.7% identity), Sudan and Egypt, and genotype C isolates to strains from various countries in western and southern Africa (89.0% identity). Genotypic diversity and genetic linkage with strains from neighbouring countries indicate intense poliovirus circulation and transmission that does not respect national borders. Therefore, eradication of poliomyelitis from CAR can only be achieved by a coordinated multinational strategy that stops poliovirus circulation in the whole of Africa.