Transmission of influenza A viruses at the human-animal interface in Ghana

2020

English

Human infections with diseases of animal origins are on a global increase and viruses have been a major component of such new infections. Influenza A viruses (IAVs) causes substantial morbidity and mortality with occasional pandemics and panzootics in humans and animals respectively. In addition the virus has zoonotic and anthroponotic potential. Therefore, circulating viruses at the human-animal interface a veterinary and public health concern and requires an OneHealth approach in effective control. In Ghana, influenza surveillance programmes and research are hospital-based and focused primarily on children with influenza-like illness and acute or severe acute respiratory infections. Surveillance in animals particularly poultry, is adhoc, intensified during outbreaks with high pathogenic avian influenza virus (HPAIV). Surveillance in swine, which are ‘mixing vessels’ for generating influenza reassortants with zoonotic and pandemic propensities are nearly non-existent. Farmers are at high-risk of becoming infected with zoonotic influenza viruses but there is no influenza surveillance programme at the humananimal interface in Ghana. The present cross-sectional study was undertaken to provide baseline information on influenza transmission at the farmer-animal interface in the Ashanti region of Ghana. The Ashanti region is the most populated region of Ghana and also large amounts of poultry and swine are kept there. The study further investigates the animal husbandry practices of animal farmers in the region as a risk of zoonotic infections. From poultry, tracheal and cloacal swabs and blood were collected, nasal swabs and blood were collected from swine and throat swabs and blood were collected from poultry and swine farmers. from poultry kept intensively on farms. Throat swab and blood were collected from the farmers. Additionally, questionnaire was administered to the farmers. All swabs were analysed for human and animal IAVs using PCR and characterised by sequencing. Sera were analysed for human, avian and swine influenza antibodies by ELISA and serotyped by haemagglutination inhibition assay. AIV was detected in poultry at a prevalence of 0.2% with higher detection in cloacal (0.3%) compared with tracheal (0.1%) swab. AIV antibodies were not detected. Poultry farmers were infected with and exposed to seasonal IAV H1N1pdm09, detected at a prevalence of 2% and 10.8% respectively. Neither AIV nor antibodies to avian H5 and H7 were detected in poultry farmers. Swine farmers were not infected with or exposed to swine IAV but were infected with seasonal IAVs, H1N1pdm09 and H3N2, detected at a prevalence of 2%. Serologically, H1N1pdm09 and H3N2 antibodies were also detected in farmers sera at an overall seroprevalence of 18.2%. Swine in the region were infected with H1N1pdm09, detected at a prevalence of 1.4%. Phylogenetically, the identified virus clustered closely with similar viruses that circulated in humans in Ghana. High titres of human H1N1pdm09 and H3N2 antibodies were also detected in swine sera. Most animal farmers were formally educated. Poultry farmers had good knowledge about poultry diseases but not poultry zoonoses. A high educational level and longer work experience improved farmers’ knowledge of poultry diseases and poultry zoonoses. Both poultry and swine farmers were aware of the possibility of becoming infected with pathogens from their animals and were also aware of several biosecurity and biosafety practices that could minimise their risk of zoonoses. However, an implementation gap was observed. Infections of swine with human influenza viruses raises concerns for the possible emergence of influenza reassortant viruses and calls for continued surveillance at the swine-human interface. Swine farmers should be vaccinated against influenza to reduce influenza anthroponoses in the Ashanti region. A further study to understand the reasons for the observed implementation gap will aid in the development of suitable control measures to minimise farmers’ risk of animal influenza infections in the Ashanti region.

Ayim-Akonor, M