Infection, Genetics and Evolution 26 (2014) 340–347
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Infection, Genetics and Evolution journal homepage: www.elsevier.com/locate/meegid
Genetic diversity of norovirus in hospitalised diarrhoeic children and asymptomatic controls in Dar es Salaam, Tanzania Sabrina Moyo a,b,⇑, Kurt Hanevik a,c, Bjørn Blomberg a,c, Oyvind Kommedal d, Kirsti Vainio e, Samuel Maselle b, Nina Langeland a,f a
Department of Clinical Science, University of Bergen, N-5021 Bergen, Norway Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Tanzania Centre for Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway d Department of Microbiology, Haukeland University Hospital, Bergen, Norway e Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway f Department of Medicine, Haukeland University Hospital, Bergen, Norway b c
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Article history: Received 10 February 2014 Received in revised form 12 June 2014 Accepted 14 June 2014 Available online 21 June 2014 Keywords: Norovirus Diarrhoea Genotyping HIV Seasonality Tanzania
a b s t r a c t This study investigated and reports norovirus diarrhoea, genetic diversity and associated clinical symptoms, HIV status and seasonality in a paediatric population of Tanzania. Stool specimens and demographic/clinical information, were prospectively collected from 705 hospitalised children with diarrhoea (cases) and 561 children without diarrhoea (controls) between 2010 and 2011. Norovirus detection was done by real-time RT-PCR. Genotype was determined using Gel-based and real time RT-PCR methods and sequencing targeting the polymerase and the capsid region respectively. Norovirus was detected in 14.3%, 181/1266 children. The prevalence of norovirus was significantly higher in cases (18.3%, 129/705) than in controls, (9.2%, 52/561), P < 0.05. Except for one child who had double infection with GI and GII all 129 cases had GII. Among controls, 23.1% had GI and 76.9% had GII. Norovirus GII.4 was significantly more prevalent in cases 87.9% than in controls 56.5%. Other genotypes detected in both cases and controls were GII.21, GII.16 and GII.g. The highest numbers of norovirus were detected in April 2011. The number of norovirus detected was significantly higher during the first than second year of life (109/540, 20.2% vs. 20/165, 12.1%). The prevalence of norovirus in HIV-positive and negative children was (21.2%, 7/33) and (10.3%, 40/390, P = 0.05) respectively, regardless of diarrhoea symptoms. No significant difference in gender, parent’s level of education or nutritional status with norovirus infection was observed within cases or controls. This study confirms the significant role of norovirus infection, especially GII.4 in diarrhoeic children who need hospitalisation and adds knowledge on norovirus epidemiology in the African region. Ó 2014 Elsevier B.V. All rights reserved.
1. Introduction Human noroviruses (NoVs) are now recognised as a common cause of outbreaks and sporadic cases of diarrhoea worldwide (Green et al., 2001). They are estimated to cause more than 1.1 million hospitalisations and 200,000 deaths in children
Contents lists available at ScienceDirect
Infection, Genetics and Evolution journal homepage: www.elsevier.com/locate/meegid
Genetic diversity of norovirus in hospitalised diarrhoeic children and asymptomatic controls in Dar es Salaam, Tanzania Sabrina Moyo a,b,⇑, Kurt Hanevik a,c, Bjørn Blomberg a,c, Oyvind Kommedal d, Kirsti Vainio e, Samuel Maselle b, Nina Langeland a,f a
Department of Clinical Science, University of Bergen, N-5021 Bergen, Norway Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Tanzania Centre for Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway d Department of Microbiology, Haukeland University Hospital, Bergen, Norway e Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway f Department of Medicine, Haukeland University Hospital, Bergen, Norway b c
a r t i c l e
i n f o
Article history: Received 10 February 2014 Received in revised form 12 June 2014 Accepted 14 June 2014 Available online 21 June 2014 Keywords: Norovirus Diarrhoea Genotyping HIV Seasonality Tanzania
a b s t r a c t This study investigated and reports norovirus diarrhoea, genetic diversity and associated clinical symptoms, HIV status and seasonality in a paediatric population of Tanzania. Stool specimens and demographic/clinical information, were prospectively collected from 705 hospitalised children with diarrhoea (cases) and 561 children without diarrhoea (controls) between 2010 and 2011. Norovirus detection was done by real-time RT-PCR. Genotype was determined using Gel-based and real time RT-PCR methods and sequencing targeting the polymerase and the capsid region respectively. Norovirus was detected in 14.3%, 181/1266 children. The prevalence of norovirus was significantly higher in cases (18.3%, 129/705) than in controls, (9.2%, 52/561), P < 0.05. Except for one child who had double infection with GI and GII all 129 cases had GII. Among controls, 23.1% had GI and 76.9% had GII. Norovirus GII.4 was significantly more prevalent in cases 87.9% than in controls 56.5%. Other genotypes detected in both cases and controls were GII.21, GII.16 and GII.g. The highest numbers of norovirus were detected in April 2011. The number of norovirus detected was significantly higher during the first than second year of life (109/540, 20.2% vs. 20/165, 12.1%). The prevalence of norovirus in HIV-positive and negative children was (21.2%, 7/33) and (10.3%, 40/390, P = 0.05) respectively, regardless of diarrhoea symptoms. No significant difference in gender, parent’s level of education or nutritional status with norovirus infection was observed within cases or controls. This study confirms the significant role of norovirus infection, especially GII.4 in diarrhoeic children who need hospitalisation and adds knowledge on norovirus epidemiology in the African region. Ó 2014 Elsevier B.V. All rights reserved.
1. Introduction Human noroviruses (NoVs) are now recognised as a common cause of outbreaks and sporadic cases of diarrhoea worldwide (Green et al., 2001). They are estimated to cause more than 1.1 million hospitalisations and 200,000 deaths in children
