Improving Current Knowledge on Seroprevalence and Genetic Characterization of Swine Influenza Virus in Croatian Pig Farms: A Retrospective Study

Andreja Jungić; Vladimir Savić; Josip Madić; Ljubo Barbić; Besi Roić; Dragan Brnić; Jelena Prpić; Lorena Jemeršić; Dinko Novosel

doi:10.3390/pathogens10111527

Improving Current Knowledge on Seroprevalence and Genetic Characterization of Swine Influenza Virus in Croatian Pig Farms: A Retrospective Study

Pathogens. 2021 Nov 22;10(11):1527. doi: 10.3390/pathogens10111527.

Authors

Andreja Jungić¹, Vladimir Savić², Josip Madić³, Ljubo Barbić³, Besi Roić¹, Dragan Brnić¹, Jelena Prpić¹, Lorena Jemeršić¹, Dinko Novosel⁴

Affiliations

¹ Department of Virology, Croatian Veterinary Institute, Savska Cesta 143, 10000 Zagreb, Croatia.
² Poultry Center, Croatian Veterinary Institute, Heinzelova 55, 10000 Zagreb, Croatia.
³ Deparment of Microbiology and Infectious Diseases with Clinic, Faculty of Veterinary Medicine, University of Zagreb, 10000 Zagreb, Croatia.
⁴ Department of Pathology, Croatian Veterinary Institute, Savska Cesta 143, 10000 Zagreb, Croatia.

Abstract

In a total of 1536 blood serum samples analysed by ELISA, antibodies for IAV nucleoprotein (NP) were detected in 30.3%. Results from HI show that the most common subtype of swIAV in the Croatian pig population was H1N1 (44.6%), followed by H3N2 (42.7%) and H1N2 (26.3%). Antibodies to at least one subtype were detected in 62.19% of blood serum samples. Detection of swIAV antigen was performed by IHC and detected in 8 of 28 lung samples collected post-mortem. The matrix (M) gene was detected in nine of one hundred and forty-two lung tissue samples and in seven of twenty-nine nasopharyngeal swabs. Phylogenetic analysis of amplified HA and NA gene fragments in Croatian isolates suggests the presence of swIAV H1avN1av.

Keywords: Croatia; H1N1; pigs; seroprevalence; swine influenza virus.