Amelioration of pneumonia with Streptococcus pneumoniae infection by inoculation with a vaccine against highly pathogenic avian influenza virus in a non-human primate mixed infection model.
BACKGROUND
Highly pathogenic avian influenza virus (HPAIV) infection has a high mortality rate in humans. Secondary bacterial pneumonia with HPAIV infection has not been reported in human patients, whereas seasonal influenza viruses sometimes enhance bacterial pneumonia, resulting in substantial morbidity and mortality. Therefore, if HPAIV infection were accompanied by bacterial infection, an increase in mortality would be expected. We examined whether a vaccine against HPAIV prevents severe morbidity caused by mixed infection with HPAIV and bacteria.


METHODS
H7N7 subtype of HPAIV and Streptococcus pneumoniae were inoculated into cynomolgus macaques with or without vaccination of inactivated whole virus particles.


RESULTS
Vaccination against H7N7 HPAIV decreased morbidity caused by HPAIV and pneumonia caused by S. pneumoniae. Bacterial replication in lungs was decreased by vaccination against HPAIV, although the reduction in bacterial colonies was not significant.


CONCLUSIONS
Vaccination against HPAIV reduces pneumonia caused by bacterial superinfection and may improve prognosis of HPAIV-infected patients.
Miyake
Taichiro
T
Department of Pathology, Shiga University of Medical Science, Otsu, Shiga, Japan.
Soda
Kosuke
K
Itoh
Yasushi
Y
Sakoda
Yoshihiro
Y
Ishigaki
Hirohito
H
Nagata
Tomoya
T
Ishida
Hideaki
H
Nakayama
Misako
M
Ozaki
Hiroichi
H
Tsuchiya
Hideaki
H
Torii
Ryuzo
R
Kida
Hiroshi
H
Ogasawara
Kazumasa
K
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001831:Body Temperature; D004195:Disease Models, Animal; D006651:Histocytochemistry / Q000662:veterinary; D053126:Influenza A Virus, H7N7 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology; D008252:Macaca fascicularis; D008992:Monkey Diseases / Q000276:immunology* / Q000382:microbiology / Q000821:virology; D009500:Neutralization Tests / Q000662:veterinary; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D011018:Pneumonia, Pneumococcal / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary* / Q000821:virology; D013296:Streptococcus pneumoniae / Q000276:immunology*; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology
D000907:Antibodies, Bacterial; D007252:Influenza Vaccines; D014613:Vaccines, Attenuated