Measles Virus Strain Diversity, Nigeria and Democratic Republic of the Congo

Jacques R Kremer,Jean-Jacques Muyembe Tamfum,Festus D Adu,Elisabeth Pukuta,Edith Nkwembe,Sunday A Omilabu,Claude P Muller,Akeeb O Bola Oyefolu,Sheilagh B Smit

doi:10.3201/eid1611.100777

Abstract

We investigated the genetic diversity of measles virus (MV) in Nigeria (2004-2005) and the Democratic Republic of the Congo (DRC) (2002-2006). Genotype B3 strains circulating in Kinshasa, DRC, in 2002-2003 were fully replaced by genotype B2 in 2004 at the end of the second Congo war. In Nigeria (2004-2005), two genetic clusters of genotype B3, both of which were most closely related to 1 variant from 1998, were identified. Longitudinal analysis of MV strain diversity in Nigeria suggested that only a few of the previously described 1997-1998 variants had continued to circulate, but this finding was concomitant with a rapid restoration of genetic diversity, probably caused by low vaccination coverage and high birth rates. In contrast, the relatively low genetic diversity of MV in DRC and the genotype replacement in Kinshasa reflect a notable improvement in local measles control.

Highlights

We investigated the genetic diversity of measles virus (MV) in Nigeria (2004–2005) and the Democratic Republic of the Congo (DRC) (2002–2006)
DRC, 2002–2003 Eight MV strains collected in Kinshasa during September 2002–January 2003 were assigned to genotype B3.1 on the basis of their MV nucleoprotein hypervariable region (MVN-HVR) sequences (Figure 1)
Their sequences differed by only 1 or 2 nt from earlier genotype B3.1 variants found in Kinshasa and Brazzaville, Congo, in 2000 [15], which suggests that MV continuously circulated in Kinshasa during 2000–2003, and that the overall genetic diversity of strains throughout this outbreak was relatively low (0.4% in the MVN-HVR)

Summary

Introduction

We investigated the genetic diversity of measles virus (MV) in Nigeria (2004–2005) and the Democratic Republic of the Congo (DRC) (2002–2006). Despite >90% reduction in the annual measles mortality rate in the World Health Organization (WHO) African Region during 2000–2006 [1], measles remains a major cause of deaths in children in sub-Saharan Africa [2,3]. During this period, routine coverage of measles-containing vaccines increased from 56% to 73% in this region, and >200 million children were vaccinated through supplementary immunization activities (SIAs) by December 2004 [4]. Measles Virus Strain Diversity, Nigeria and DRC in epidemiologic patterns in both countries that can be only partially explained by differences in vaccination practices

Methods

Results

Discussion

Conclusion