Highly pathogenic or low pathogenic avian influenza virus subtype @entity281 in XXXX lungs: small differences in general acute responses.

@entity778 @entity1573 @entity72105 @entity281
Avian influenza virus can be divided into two groups, highly pathogenic avian influenza virus (HPAI) and low pathogenic avian influenza virus (LPAI) based on their difference in virulence. To investigate if the difference in clinical outcome between LPAI and HPAI in @entity1573 is due to immunological host responses in the lung within the first 24 hours post @entity281 (hpi), @entity1573 were infected with LPAI or @entity778 . Virus was found in the caudal and cranial part of the lung. With LPAI, virus was localised around the intrapulmonary bronchus and secondary bronchi. In sharp contrast, HPAI was detected throughout the whole lung. However, based on viral RNA levels, no quantitative difference was observed between LPAI and @entity778 birds. In infected areas of the lungs, an influx of @entity72105 + cells as well as KUL01+ macrophages and dendritic cells (DC) occurred as fast as 8 hpi in both infected groups. No major difference between LPAI and @entity778 birds in the induction of cytokines and interferons at mRNA level in lung tissue was found.In conclusion, the differences in lethality for @entity1573 infected with LPAI or HPAI could be ascribed to difference in location of the virus. However similar amounts of viral RNA, similar cytokine mRNA levels, and similar influxes of @entity72105 + and KUL01+ macrophages and DC were found between HPAI and LPAI in the lungs. A cytokine storm at mRNA level as described for mammals was not observed in the lungs of @entity778 birds within 24 hpi.
