Molecular characterization of measles viruses that circulated in Cameroon between 2010 and 2011

Abstract

BackgroundMeasles virus (MeV) is monotypic, but genetic variation in the hemagglutinin H and nucleoprotein N genes can be analyzed by molecular epidemiologic techniques and used to study virus transmission patterns. The World Health Organization currently recognizes 8 clades (A-H) within which are 24 genotypes of MeV and one provisional genotype, d11. Genotype B3 is clearly the endemic genotype in most of African continent where it is widely distributed. We provide an update on the molecular characterization of wild-type MeVs that circulated in Cameroon between 2010 and 2011.FindingsViral RNA was extracted directly from samples obtained from clinically diagnosed measles patients using QIAamp viral RNA Mini Kit. Reverse transcription and PCR amplification of 634 nucleotides of the N gene was performed using the SuperScript™ III One-Step. Sequence analysis of 450 of the 634 nucleotides using Clustal X 2.0 program for multiple alignments and Mega version 5 for phylogenic analysis indicated that all the viruses belonged to genotype B3 with two distinct clusters. Twenty three (77%) belonged to subgroup B3.1 and the other 7 (23%) belonged to B3.3 a recently described subtype. Circulation of cluster 3 was detected in the Far-North Region (5/7) particularly along the Chad-Cameroon border in 2010 and later in Yaounde (2/7 in Biyem-assi Health District) the capital city of Cameroon in 2011.ConclusionThis study highlights the endemic circulation in Cameroon of MeV B3 subtype 1, which probably has its source in the neighboring Nigeria, and the presence of the new subtype B3.3, suggesting a possible importation from Northern Africa where it was first described between 2008 and 2009.

Molecular characterisation of measles virus strains among refugees from Central African Republic in Cameroon in 2014

“…Genotype B3 is the endemic genotype in most of the African continent, with the exception of the North African countries in the Eastern Mediterranean Region [5,17]. MeV genotype B3 strains that are more closely related to reference strain MVi/ New York.USA/0.94, which appears to be more limited to Western Africa [32], were not detected in this study in contrast to the earlier findings [22] .In addition, the genotype B3 reference strain MVs/Sfax.TUN/09.09 was absent, contrary to what was observed in the Far North region of Cameroon [22]. MeVs from clade B are endemic in sub-Saharan Africa [33], and B3 genotype has been detected in several countries, including Ghana, Gambia, Nigeria, Libya and Tunisia, elsewhere in Europe (France and Germany) and in the USA [34,35].…”

“…Bootstrap values were obtained through 1000 resampling of datasets. MeV sequences previously found in Cameroon [21,22] and the CAR [28] were also added to this analysis. MeV RNA was detected in 83% (25/30) of the suspected cases by real-time RT-PCR including eight of eight children aged 9-59 months, and five of five samples from children <9 months.…”

“…Bootstrap values were obtained through 1000 resampling of datasets. MeV sequences previously found in Cameroon [21, 22] and the CAR [28] were also added to this analysis.…”

“…MeV was first isolated in Cameroon in 1983; these strains belonged to genotype B1 [19,20]. MeV strains found in Cameroon in 2001 were genotype B3 [21] more recently, Demanou and collaborators showed that the circulating MeV strains in Cameroon between 2010 and 2011 were also the B3 genotypes [22] On December 10, 2012, the Central African Republic (CAR) experienced a serious political crisis [23] that led to displacement of a significant portion of the population as refugees into East Cameroon. There are no current reports of circulating MeV genotypes from East Cameroon.…”

“…MeV was first isolated in Cameroon in 1983; these strains belonged to genotype B1 [19, 20]. MeV strains found in Cameroon in 2001 were genotype B3 [21] more recently, Demanou and collaborators showed that the circulating MeV strains in Cameroon between 2010 and 2011 were also the B3 genotypes [22]…”