Surveillance for Influenza Viruses in Poultry and Swine, West Africa, 2006–2008

Couacy‐Hymann, Emmanuel; Kouakou, Viviane A.; Aplogan, Gilbert L.; Awoume, Félix; Kouakou, Casimir; Kakpo, Lamidi; Sharp, Bridgett; McClenaghan, Laura; McKenzie, Pamela; Webster, Robert G.; Webby, Richard J.; Ducatez, Mariette

doi:10.3201/eid1809.111296

Cited by 40 publications

(50 citation statements)

References 34 publications

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“…These results may also suggest persistent circulation of virulent NDV strains in local chickens independent of a recognized epizootic. In a recent sur- veillance study focused on avian influenza, we have shown that 32% of bird serum samples from Togo were positive for NDV antibodies by the HI test (28). The high seroprevalence of NDVs may indeed explain in part the absence of clinical signs, despite their virulent pathotype.…”

Section: Discussionmentioning

confidence: 99%

Phylogenetic and Pathotypic Characterization of Newcastle Disease Viruses Circulating in West Africa and Efficacy of a Current Vaccine

et al. 2013

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e Newcastle disease (ND) is a deadly avian disease worldwide. In Africa, ND is enzootic and causes large economic losses, but little is known about the Newcastle disease virus (NDV) strains circulating in African countries. In this study, 27 NDV isolates collected from apparently healthy chickens in live-bird markets of the West African countries Benin and Togo in 2009 were characterized. All isolates had polybasic fusion (F)-protein cleavage sites and were shown to be highly virulent in standard pathogenicity assays. Infection of 2-week-old chickens with two of the isolates resulted in 100% mortality within 4 days. Phylogenetic analysis of the 27 isolates based on a partial F-protein gene sequence identified three clusters: one containing all the isolates from Togo and one from Benin (cluster 2), one containing most isolates from Benin (cluster 3), and an outlier isolate from Benin (cluster 1). All the three clusters are related to genotype VII strains of NDV. In addition, the cluster of viruses from Togo contained a recently identified 6-nucleotide insert between the hemagglutinin-neuraminidase (HN) and large polymerase (L) genes in a complete genome of an NDV isolate from this geographical region. Multiple strains that include this novel element suggest local emergence of a new genome length class. These results reveal genetic diversity within and among local NDV populations in Africa. Sequence analysis showed that the F and HN proteins of six West African isolates share 83.2 to 86.6% and 86.5 to 87.9% identities, respectively, with vaccine strain LaSota, indicative of considerable diversity. A vaccine efficacy study showed that the LaSota vaccine protected birds from morbidity and mortality but did not prevent shedding of West African challenge viruses.

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Section: Discussionmentioning

confidence: 99%

Phylogenetic and Pathotypic Characterization of Newcastle Disease Viruses Circulating in West Africa and Efficacy of a Current Vaccine

et al. 2013

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“…We carried out a large-scale active surveillance study of animal influenza in Togo from 2009 through 2014 with close to 10 000 avian and swine swabs tested for the presence of influenza virus genome. As observed in the neighboring Benin and Côte d’Ivoire, none of the animal swabs collected in Togo through 2012 had been positive for influenza A virus, nor had any animal serum tested positive for influenza A virus antibodies (Couacy-Hymann et al, 2012). Again from 2011 through 2014, no avian samples tested positive for influenza virus genome or antibody in the 3 countries (Fuller et al, 2014).…”

Section: Introductionmentioning

confidence: 88%

Influenza A(H1N1)pdm09 virus in pigs, Togo, 2013

Ducatez

Awoume²,

Webby

2015

Veterinary Microbiology

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We collected 325 nasal swabs from freshly slaughtered previously healthy pigs from October 2012 through January 2014 in a slaughterhouse near Lomé in Togo. Influenza A virus genome was detected by RT-PCR in 2.5% to 12.3% of the pooled samples, and results of hemagglutinin subtyping RT-PCR assays showed the virus in all the positive pools to be A(H1N1)pdm09. Virus was isolated on MDCK cells from a representative specimen, A/swine/Togo/ONA32/2013(H1N1). The isolate was fully sequenced and harbored 8 genes similar to A(H1N1)pdm09 virus genes circulating in humans in 2012–2013, suggesting human-to-swine transmission of the pathogen.

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“…Since influenza virus is excreted continuously in faeces for only about 12 days in birds (Henaux and Samuel, 2011;Couacy-Hymann et al, 2012), it is possible that the period of virus shedding could have been missed in the birds sampled. It could also be due to too low titres of the virus in faeces which makes it undetectable by RT-PCR.…”

Section: Discussionmentioning

confidence: 99%

Flock-Based Surveillance for Low Pathogenic Avian Influenza Virus in Commercial Breeders and Layers, Southwest Nigeria

Oluwayelu¹,

Omolanwa²,

Adebiyi³

et al. 2016

AJID

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Background: Flock surveillance systems for avian influenza (AI) virus play a critical role in countries where vaccination is not practiced so as to establish the epidemiological characteristics of AI needed for the development of prevention and control strategies in such countries. Materials and Methods: As part of routine AI monitoring in southwest Nigeria, a competitive ELISA was used for detecting influenza A virus antibodies in the sera of 461 commercial breeder and layer birds obtained from different flocks in Oyo State, Nigeria while haemagglutination inhibiting antibodies against low pathogenic AI viruses (LPAIVs) were detected using H5N2, H7N7 and H9N2 subtype-specific antigens. Suspensions prepared from cloacal swabs were tested for AI virus RNA using reverse transcriptase-polymerase chain reaction. Results: Results showed that influenza A virus antibody prevalence was 12.8% and 9.3% for breeders and layers, respectively while HI assay revealed 22.0%, 2.0% and 78.0% prevalence of LPAIV H5N2, H7N7 and H9N2 antibodies respectively. All cloacal swab suspensions were negative for AIV RNA. Conclusion: Since LPAI infections result in decreased or complete cessation of egg production in breeder and layer birds, increased infection severity due to co-infection with other poultry viruses have occasionally been transmitted to humans, the detection of LPAIV H5N2, H7N7 and H9N2 antibodies in these birds is of both economic and public health significance. These findings underscore the need for continuous flock monitoring as part of early warning measure to facilitate rapid detection and sustainable control of AI in Nigerian poultry.

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Surveillance for Influenza Viruses in Poultry and Swine, West Africa, 2006–2008

Abstract: West Africa might be an animal influenza–free zone.

Cited by 40 publications

References 34 publications

Phylogenetic and Pathotypic Characterization of Newcastle Disease Viruses Circulating in West Africa and Efficacy of a Current Vaccine

Phylogenetic and Pathotypic Characterization of Newcastle Disease Viruses Circulating in West Africa and Efficacy of a Current Vaccine

Influenza A(H1N1)pdm09 virus in pigs, Togo, 2013

Flock-Based Surveillance for Low Pathogenic Avian Influenza Virus in Commercial Breeders and Layers, Southwest Nigeria

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