Human metapneumovirus epidemiological and evolutionary patterns in Coastal Kenya, 2007-11.
Human metapneumovirus (HMPV) is an important global cause of severe acute respiratory infections in young children and the elderly. The epidemiology of HMPV in sub-Saharan Africa is poorly described and factors that allow its recurrent epidemics in communities not understood.



We undertook paediatric inpatient surveillance for HMPV in Kilifi County Hospital (KCH) of Coastal Kenya between 2007 and 2011. Nasopharyngeal samples collected from children aged 1 day-59 months admitted with severe or very severe pneumonia, were tested for HMPV using real-time polymerase chain reaction (RT-PCR). Partial nucleotide sequences of the attachment (G) and fusion (F) surface proteins of positive samples were determined and phylogenetically analyzed.



HMPV was detected in 4.8 % (160/3320) of children [73.8 % (118/160) of these less than one year of age], ranging between 2.9 and 8.8 % each year over the 5 years of study. HMPV infections were seasonal in occurrence, with cases predominant in the months of November through April. These months frequently coincided with low rainfall, high temperature and low relative humidity in the location. Phylogenetic analysis of partial F and G sequences revealed three subgroups of HMPV, A2 (74 %, 91/123), B1 (3.2 %, 4/123) and B2 (22.8 %, 28/123) in circulation, with subgroup A2 predominant in majority of the epidemic seasons. Comparison of G sequences (local and global) provided a greater phylogenetic resolution over comparison of F sequences and indicated presence of probable multiple G antigenic variants within the subgroups due to differences in amino acid sequence, encoded protein length and glycosylation patterns.



The present study reveals HMPV is an important seasonal contributor to respiratory disease hospitalization in coastal Kenya, with an evolutionary pattern closely relating to that of respiratory syncytial virus.
Kenya Medical Research Institute (KEMRI) -Wellcome Trust Research Programme, Kilifi, KEMRI Centre for Geographic Medicine Research - Coast, Kilifi, Kenya. BOwor@kemri-wellcome.org.
Betty E
BE
Owor
Kenya Medical Research Institute (KEMRI) -Wellcome Trust Research Programme, Kilifi, KEMRI Centre for Geographic Medicine Research - Coast, Kilifi, Kenya.
Geoffrey N
GN
Masankwa
Kenya Medical Research Institute (KEMRI) -Wellcome Trust Research Programme, Kilifi, KEMRI Centre for Geographic Medicine Research - Coast, Kilifi, Kenya.
Lilian C
LC
Mwango
Kenya Medical Research Institute (KEMRI) -Wellcome Trust Research Programme, Kilifi, KEMRI Centre for Geographic Medicine Research - Coast, Kilifi, Kenya.
Regina W
RW
Njeru
Kenya Medical Research Institute (KEMRI) -Wellcome Trust Research Programme, Kilifi, KEMRI Centre for Geographic Medicine Research - Coast, Kilifi, Kenya.|Department of Biomedical Sciences, Pwani University, Kilifi, Kenya.
Charles N
CN
Agoti
Kenya Medical Research Institute (KEMRI) -Wellcome Trust Research Programme, Kilifi, KEMRI Centre for Geographic Medicine Research - Coast, Kilifi, Kenya. JNokes@kemri-wellcome.org.|School of Life Sciences and WIDER, University of Warwick, Coventry, UK. JNokes@kemri-wellcome.org.
D James
DJ
Nokes
D000595:Amino Acid Sequence; D000940:Antigenic Variation; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007630:Kenya / Q000453:epidemiology; D008297:Male; D029121:Metapneumovirus / Q000235:genetics / Q000302:isolation & purification*; D009305:Nasopharynx / Q000821:virology; D018184:Paramyxoviridae Infections / Q000453:epidemiology* / Q000821:virology; D010802:Phylogeny; D011014:Pneumonia / Q000453:epidemiology / Q000821:virology*; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction; D012141:Respiratory Tract Infections / Q000453:epidemiology; D012621:Seasons
Genetic diversity; Human metapneumovirus; Kenya; Kilifi; Respiratory virus