| 1. |
- Ayukekbong, James A., et al.
(författare)
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Monitoring of seasonality of norovirus and other enteric viruses in Cameroon by real-time PCR : an exploratory study
- 2014
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Ingår i: Epidemiology and Infection. - : Cambridge University Press. - 0950-2688 .- 1469-4409. ; 142:7, s. 1393-1402
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Tidskriftsartikel (refereegranskat)abstract
- We studied the seasonal fluctuation of norovirus and other enteric viruses in Cameroon. Two hundred participants aged between 1 and 69 years were prospectively followed up. Each participant provided monthly faecal samples over a 12-month period. A total of 2484 samples were tested using multiplex real-time PCR assay for the detection of norovirus, rotavirus and enterovirus. The effect of weather variables and risk factors were analysed by Pearson correlation and bivariate analysis. Overall, enterovirus was the most commonly detected virus (216% of specimens), followed by norovirus (39%) and rotavirus (04%). Norovirus and enterovirus were detected throughout the year with a peak of norovirus detection at the beginning of the rainy season and a significant alternation of circulation of norovirus genogroups from one month to the next. Age <5 years and consumption of tap water were risk factors for norovirus infection. Better understanding of factors influencing transmission and seasonality may provide insights into the relationship between physical environment and risk of infection for these viruses.
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| 2. |
- Ayukekbong, James, et al.
(författare)
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Enteric viruses in healthy children in Cameroon: viral load and genotyping of norovirus strains.
- 2011
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Ingår i: Journal of medical virology. - : Wiley. - 1096-9071 .- 0146-6615. ; 83:12, s. 2135-42
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Tidskriftsartikel (refereegranskat)abstract
- Data regarding prevalence of noroviruses (NoVs) among asymptomatic persons are scarce. The current study carried out on samples from Cameroon describes the asymptomatic shedding of NoVs and other enteric viruses in healthy children and in adults infected with HIV but lacking symptoms of gastroenteritis. Enteric viruses were common with a prevalence of 53.7% in the children, and 35.5% in the adult participants. Multiple enteric viruses (2-5 agents) were detected in fecal samples from 65% of the children, and co-infection with NoV was demonstrated in almost all cases of multiple infections. NoV viral loads in the healthy children were within disease causing range and significantly higher than those observed in the adults (P<0.01). Sequencing and genotyping of NoV strains by phylogeny showed a marked diversity within two distinct genogroups, GI and GII, and strains clustered with genotypes GI.3, GII.17, GII.8, and GII.4. Genetic similarities to recent outbreak strains from other continents suggest a rapid circulation of NoVs that includes healthy children, who may constitute a reservoir for pathogenic NoVs.
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| 3. |
- Ayukekbong, James, et al.
(författare)
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Molecular Analysis of Enterovirus in Cameroon by Partial 50UTR-VP4 Gene Sequencing Reveals a High Genetic Diversity and Frequency of Infections
- 2014
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Ingår i: Journal of Medical Virology. - : Wiley. - 0146-6615. ; 86:12, s. 2092-2101
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Tidskriftsartikel (refereegranskat)abstract
- Enteroviruses (EVs) often infect humans, presenting as endemic or epidemic infections. In this study, the diversity of infecting EVs was studied among 146 children and 137 adults in a small community in Cameroon. The participants provided 2,458 fecal samples during 1-year monthly collection; 10 or more samples were obtained from 55%. Partial 5UTR-VP4 region could be sequenced in 393/547 PCR positive samples obtained from 119 children and 85 adults. EV-RNA was detected in at least one sample from 235 participants (83%) during the study period. A total of 121 different strains were identified, 66 infected only children, 29 only adults, and 26 infected both children and adults. There were children with up to five episodes with different strains, and adults with up to four such episodes. Infants aged <5 years were significantly more often EV infected compared to older participants. Infections with species EV-C constituted two third of all cases, and overall EV infections were more common during the rainy season. Species EV-B more often infected children than adults. Most strains were detected only for certain months of the year; however five strains were observed during the time spans of 5-10 months. Two strains were excreted up to eight months in three children and one adult. In 11 of the 128 families with paired samples the child and the adult were infected simultaneously by the same strain, indicating common source of infection. The study revealed a surprising complexity of EV ecosystem in a single community. J. Med. Virol. 86:2092-2101, 2014. (c) 2014 Wiley Periodicals, Inc.
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| 4. |
- Ayukekbong, James, et al.
(författare)
-
Monitoring of seasonality of norovirus and other enteric viruses in Cameroon by real-time PCR: an exploratory study
- 2014
-
Ingår i: Epidemiology and Infection. - : Cambridge University Press (CUP). - 0950-2688 .- 1469-4409. ; 142:7, s. 1393-1402
-
Tidskriftsartikel (refereegranskat)abstract
- We studied the seasonal fluctuation of norovirus and other enteric viruses in Cameroon. Two hundred participants aged between 1 and 69 years were prospectively followed up. Each participant provided monthly faecal samples over a 12-month period. A total of 2484 samples were tested using multiplex real-time PCR assay for the detection of norovirus, rotavirus and enterovirus. The effect of weather variables and risk factors were analysed by Pearson correlation and bivariate analysis. Overall, enterovirus was the most commonly detected virus (216% of specimens), followed by norovirus (39%) and rotavirus (04%). Norovirus and enterovirus were detected throughout the year with a peak of norovirus detection at the beginning of the rainy season and a significant alternation of circulation of norovirus genogroups from one month to the next. Age <5 years and consumption of tap water were risk factors for norovirus infection. Better understanding of factors influencing transmission and seasonality may provide insights into the relationship between physical environment and risk of infection for these viruses.
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| 5. |
- Ayukekbong, James, et al.
(författare)
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Pattern of Circulation of Norovirus GII Strains during Natural Infection
- 2014
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Ingår i: Journal of Clinical Microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 52:12, s. 4253-4259
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Tidskriftsartikel (refereegranskat)abstract
- Norovirus (NoV) is considered a major cause of nonbacterial gastroenteritis among people of all ages worldwide, but the natural course of infection is incompletely known. In this study, the pattern of circulation of NoVs was studied among 146 children and 137 adults in a small community in southwestern Cameroon. The participants provided monthly fecal samples during a year. NoV RNA was detected in at least one sample from 82 (29%) of the participants. The partial VP1 region could be sequenced in 36 NoV GII-positive samples. Three different genotypes were identified (GII.1, GII.4, and GII.17), with each genotype circulating within 2 to 3 months and reappearing after a relapse period of 2 to 3 months. Most infections occurred once, and 2 episodes at most within a year were detected. No difference in the frequency of NoV infection between children and adults was recorded. The same genotype was detected for a maximum of 2 consecutive months in 3 children only, suggesting that a less than 30-day duration of viral shedding in natural infection was common. Reinfection within a year with the same genotype was not observed, consistent with short-term homotypic immune protection. The study revealed that NoV strains are circulating with a limited duration of viral shedding both in the individuals and the population as part of their natural infection. The results also provide evidence of cross-protective immunity of limited duration between genotypes of the same genogroup.
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| 6. |
- Ayukekbong, James, et al.
(författare)
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Role of noroviruses as aetiological agents of diarrhoea in developing countries
- 2015
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Ingår i: Journal of General Virology. - : Microbiology Society. - 0022-1317 .- 1465-2099. ; 96, s. 1983-1999
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Tidskriftsartikel (refereegranskat)abstract
- Diarrhoea is considered to be the second leading cause of death due to infections among children <5 years of age worldwide that may be caused by bacteria, parasites, viruses and non-infectious agents. The major causative agents of diarrhoea in developing countries may vary from those in developed countries. Noroviruses are considered to be the most common cause of acute diarrhoea in both children and adults in industrialized countries. On the other hand, there is a lack of comprehensive epidemiological evidence from developing countries that norovirus is a major cause of diarrhoea. In these regions, asymptomatic norovirus infections are very common, and similar detection rates have been observed in patients with diarrhoea and asymptomatic persons. This review summarizes the current knowledge of norovirus infection in developing countries and seeks to position infections with noroviruses among those of other enteropathogens in terms of disease burden in these regions.
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| 7. |
- Ayukekbong, James, et al.
(författare)
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Shift of Enterovirus species among children in Cameroon - Identification of a new enterovirus, EV-A119
- 2013
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Ingår i: Journal of Clinical Virology. - : Elsevier BV. - 1386-6532. ; 58:1, s. 227-232
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Tidskriftsartikel (refereegranskat)abstract
- Background: Infections caused by human enteroviruses (EVs) are often asymptomatic or mild, although they may cause more severe illnesses as meningitis and acute flaccid paralysis. EVs have globally posed a threat to children, and outbreaks of aseptic meningitis and hand, foot and mouth disease are frequently reported. Objective: To identify EV strains circulating among healthy children in a small community in Limbe, Cameroon two years apart. Study design: Species and EV types were obtained by partial 5'UTR-VP4 and VP1 sequencing of RNA from stool samples collected in October 2009 and September 2011 from 150 children in Cameroon. Results: In all, 74 children (49%) were infected with 28 different types of EV. There were 29 (54%) infected children in 2009, and 45 (47%) in 2011. There was a significant difference between detected species of EV, with 15 (47%) children infected with EV-A in 2009, and 22 (71%) with EV-B in 2011 (p = 0.0001). In 2009, one child was infected by a divergent EV, which was most similar to EV-A90. Based on the complete VP1 sequence, it was shown to be a new EV designated EV-A119. Conclusion: The current study shows a high heterogeneity of circulating EV types among children in Limbe, Cameroon, and a previously not described shift in predominating EV species. (C) 2013 Elsevier B. V. All rights reserved.
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| 8. |
- Oyero, O. G., et al.
(författare)
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High dengue NS1 antigenemia in febrile patients in Ibadan, Nigeria
- 2014
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Ingår i: Virus Research. - : Elsevier BV. - 0168-1702. ; 191, s. 59-61
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Tidskriftsartikel (refereegranskat)abstract
- We conducted a dengue seroprevalence survey among febrile patients positive or negative for malaria in lbadan, Nigeria. Dengue IgG and NS1 seroprevalence of 73% and 35%, respectively, was observed, and 43% of those with malaria had acute dengue infection (NS1 determination). On the other hand, all participants with malaria were IgG dengue seropositive consistent with the endemicity of both arthropod-borne infections in the region. These data indicate that dengue is emerging as a major and neglected cause of fever in Nigeria. (C) 2014 Elsevier B.V. All rights reserved.
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| 9. |
- Oyero, O. G., et al.
(författare)
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Molecular characterization of diverse species enterovirus-B types from children with acute flaccid paralysis and asymptomatic children in Nigeria
- 2014
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Ingår i: Virus Research. - : Elsevier BV. - 0168-1702. ; 189, s. 189-193
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Tidskriftsartikel (refereegranskat)abstract
- Non-polio enteroviruses (NPEVs) have often been identified in association with acute flaccid paralysis (AFP) in most polio surveillance studies worldwide. In a polio endemic country like Nigeria, there is need for distinction of AFP due to poliovirus and those potentially due to NPEVs. This study was undertaken to characterize the enterovirus (EV) types circulating in both children with and without AFP in Nigeria. Of fecal sample from 966 children with AFP, 96 (10%) were positive for NPEVs in RD cells, while 42(5.5%) of 756 samples from non-AFP children was positive. Genotyping of all NPEV isolates was done by partial VP1 gene sequencing and phylogenetic analysis. EV-B was the predominant species detected (84%) and infection was common in children with AFP with CVB3, E6, and E11 constituting the predominant types detected. The CVB3 isolates cluster with Chinese CVB3 isolate recently detected in a newborn with AFP. There was also a remarkable clustering of isolates such as E6, E12, E13, E24, E30 and E33 to types previous detected in West Africa suggesting a probable circulation of these lineages in the region. Taken together, this study reveals a diverse species EV-B types in AFP cases and highlights the fact that other neurotropic EVs circulate in asymptomatic persons. Improved continuous surveillance of NPEV is warranted as in the likely attainment of polio eradication, other neurotropic EVs may emerge causing similar paralytic diseases.
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