Continuous Circulation of Human derived Pandemic H1N1pdm09 Influenza Virus in Nigerian Pigs: Implication for Public Health and Pandemic Preparedness

Ijomanta, J.1,+, Asala, O.1, Bitrus, M.1, Musa, A.2, Shittu, I.1, Joannis, T.1, Nwosuh, C.1 and 1Meseko, C.*

1Regional Centre for Animal Influenza, National Veterinary Research Institute, Vom Nigeria; 2Veterinary Department, Plateau State Ministry of Agriculture, Jos Nigeria

+presenting author

*Corresponding author: cameseko@yahoo.com

Influenza virus A belongs to the family Orthomyxoviridae and is divided into subtypes H1-18. The virus affects a wide range of avian and mammalian hosts, subtypes H1; H3; H5; H7 and H9 have been reported to cause fatal infections that can adversely affect socio-economics and public health. In April 2009, WHO declared influenza pandemic when H1N1pdm09 spread to 214 countries and an estimated 151,700 –575 400 deaths were recorded. The virus was subsequently transmitted to pigs and had remained enzootic being detected in many countries including Nigeria.

In this study, a total of 143 tracheal swabs were collected during a targeted active surveillance of apparently healthy pigs in Jos abattoir, Plateau state from December 2017 through February 2018. The samples were analyzed for Influenza A by conventional One-step RT-PCR protocol targeting the matrix. To subtype the Influenza A viruses, multiplex RT-qPCR assays targeting the Hemagglutinin (H1pdm, H1avian, H1human and H3) and neuraminidase (N1, N2, N1pdm) were used. In all, 51 (35%) samples were positive for Influenza A while four of the ten selected samples for subtyping were identified as H1N1pdm09.

In a previous study carried out at the human-animal interface, circulation of H1N1pdm09 was reported in southwest Nigeria. Also, follow up studies revealed seroprevalence ranging from 20-60% in pigs. Here, we report a more recent and continuous circulation of the virus in pigs in North central Nigeria since it was first declared a pandemic in 2009. The virus in human is now seasonal and can easily be managed with vaccination. Currently, there is no vaccination programme for swine influenza in Nigeria therefore maintaining H1N1pdm09 in pigs poses great public health risk. Possible mutations and reassortments may result in emergence of novel virus with pandemic potential.

Keywords: surveillance; Influenza A virus; Nigeria; Pandemics; Pigs