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

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

doi:10.3390/pathogens10111527

Andreja Jungić, Jelena Prpić + Show 7 more

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https://doi.org/10.3390/pathogens10111527

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Journal: Pathogens	Publication Date: Nov 22, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: Croatian Veterinary Institute, University of Zagreb

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.

Highlights

Swine influenza (SI) is one of the major viral diseases of pigs caused by influenzaA viruses (IAVs)
In pigs kept in backyard farms in the continental part of Croatia, the highest mean seroprevalence of 89.7% was found on Brod–Posavina County, while no positive sample was found in backyard farms on Zagreb County
H3N2 subtype was not detected in backyard farms in Karlovac, Šibenik–Knin and Zagreb County counties, as well as H1N2 subtype, which was not detected in nine counties

Summary

Introduction

Swine influenza (SI) is one of the major viral diseases of pigs caused by influenzaA viruses (IAVs). Swine influenza (SI) is one of the major viral diseases of pigs caused by influenza. The morbidity rate in infected swine herds can be as high as 100%, the mortality rate of primary infections with swine influenza A viruses (swIAV) is very low and their involvement as important coinfection with other pathogens can cause a high mortality rate, especially in young pigs. The nature of the disease is always difficult when it is associated with other viral pathogens such as porcine respiratory coronavirus (PRCV), porcine reproductive and respiratory syndrome virus (PRRSV), the porcine circovirus type 2 (PCV2) or bacteria that can cause secondary infections such as Actinobacillus pleuropneumoniae, Pasteurella multocida, Haemophilus parasuis and Streptococcus suis type 2 [1,2,3,4]. The natural reservoir for IAVs is waterfowl, but humans and pigs are considered hosts

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