Vaccination Statistics and Reality： How Many Horses Are Really Vaccinated against Equine Influenza？

Standard schedules for equine influenza vaccinations have been published in Finland. However, no knowledge about the actual number of vaccinations has been available. Based on previous preliminary studies in slaughterhouses and among horse owners, it was suspected that vaccination recommendations are not always followed. The aims were to investigate vaccination status against equine influenza among Finnish racehorses in regional competitions. Vaccination status was investigated： （1） by utilizing database vaccination information of show jumping and dressage horses and （2） by carrying out a survey among horse industry experts. A total of 400 horses were selected at the beginning of the Finnish competition season in 2012 and five experts （key persons） were invited to a repeated survey implemented by Delphi techniques. Overall, 50%-100% of horses were properly vaccinated depending on the source available. Thirty-four percent （34%） of the horses had the competition license but no vaccination markings in the database. Differences between types of competition （show jumping and dressage） and between Southern and Northern parts of Finland were found. Vaccinations of show jumping horses were registered more often than vaccinations of dressage horses. Ninety percent （90%） of unvaccinated horses in the database were eight years or older. It can be concluded that equine influenza vaccination registry coverage among racehorses in Finland is incomplete. This poses a risk of misunderstanding, and the growing responsibility of competition organizers.

Equine ANP32 proteins support influenza A virus RNA polymerase activity

Host ANP32 family proteins are crucial for maintaining the activity of influenza RNA polymerase and play an important role in the cross-species transmission of influenza viruses.To date,the molecular properties of equine ANP32(eqANP32)protein are poorly understood,particularly the mechanisms that affect equine influenza virus(EIV)RNA polymerase activity.Here,we found that there are six alternative splicing variants of equine ANP32A(eqANP32A)with different levels of expression.Further studies showed that these six splicing variants of eqANP32A supported the activity of EIV RNA polymerase to varying degrees,with the variant eqANP32A_X2 having the highest expression abundance and exhibiting the highest support of polymerase activity.Sequence analysis demonstrated that the differences in the N-Cap regions of the six splicing variants significantly affected their N-terminal conformation,but did not affect their ability to bind RNA polymerase.We also demonstrated that there is only one transcript of eqANP32B,and that this transcript showed only very low support to the EIV RNA polymerase.This functional defect in eqANP32B is caused by the sequence of the 110–259 amino acids at its Cterminus.Our results indicated that it is the eqANP32A_X2 protein that mainly determines the efficiency of the EIV replication in horses.In conclusion,our study parsed the molecular properties of eqANP32 family proteins and revealed the sequence features of eqANP32A and eqANP32B,suggesting for the first time that the N-Cap region of ANP32A protein also plays an important role in supporting the activity of the influenza virus polymerase.