Seroprevalence of Swine Influenza A virus circulating in pigs from Southern Kaduna, Nigeria

Abstract

Influenza virus is shared between humans and swine since the 1918 Spanish flu pandemic. It is a virus of public health implication. Pigs play an important role in the ecology of Influenza as the mixing vessel for the emergence of a novel pandemic strains. Three factors supporting the mixing vessel hypothesis are: susceptibility of swine to avian and human viruses; reassortment of swine/avian/human viruses’ occurring in pigs which can transmit reassortant influenza virus to humans through occupational exposures. This study provides information on the serotypes of some influenza virus in the pig market in Kaduna State. A total of 305 samples were collected from December, 2017 to early February and in June, 2018. Rectal temperature before slaughter was recorded and blood were collected from exsanguinated pigs at Katsit slaughter slab. Serum were separated and kept at -20°C until further analysis. The sera were tested for swine influenza by competitive ELISA. The result showed overall seroprevalence of 28.20% (n=86). Of this, male animals’ represented 9.84 % and the female 18.36% of the total percentage. The breakdown results for each month was as follows: [December; 11 positives (3.61%), January; 22 positives (7.21%), February 20 positives (6.56%), June; 33 positives (10.82%)]. This study showed that Swine Influenza A virus is in circulation among pigs in Southern Kaduna with prevalence peaking at two seasons which coincides with the harmattan in January and the onset of rains in June. The high prevalence means possible transmission of the virus to humans who interface with Swine. There was no correlation between the influenza status and the sex of the swine under study. Also temperature distribution does not show difference between sexes, although there appears a slight difference in temperature distribution between statuses.