OKAMURA Masashi Professor

Theme1)Control of foodborne pathogen contamination of chicken flocks, chicken meat and eggs
2)Elucidation of host-specific infection mechanisms of pathogens

My DreamGlobal food safety and stable food supply based on disease control of livestock and poultry
Field Microbiology, Avian diseases, Food hygiene, Zoonoses
Keyword Salmonella, Poultry, Campylobacter, Food-borne diseases, Zoonoses


1. Establishment of measures to reduce contamination of poultry flocks and chicken meat by foodborne pathogens
The number of foodborne illnesses caused by contaminated chicken meat continues to increase. The main causative bacteria are Salmonella and Campylobacter. In order to establish measures to reduce the contamination of poultry flocks with food poisoning bacteria at the consumption stage, the poultry processing stage, and even at the production stage on farms, we have been investigating the contamination of poultry flocks and poultry meat at farms and poultry processing plants. The future challenge is to elucidate the contamination pathways.

2. Pathogenic mechanism and host specificity of fowl typhoid
Most of the pathogenic Salmonella serotypes cause diarrhea and other gastrointestinal symptoms in various animals (food poisoning in humans), while only a few serotypes (less than 10) cause sepsis and death in specific animal hosts. However, the mechanism of this strong host-specific virulence has not yet been clarified so far. We identified 50 antigens expressed by Salmonella enterica serotype Gallinarum in infected chickens and narrowed down the genes that are thought to be important for the pathogenesis of fowl typhoid and the virulence of the organism, based on the phenotype (decreased virulence) in chickens of mutant strains. We are trying to clarify how these genes are involved in the development of fowl typhoid and how they are involved in the mechanism that makes the bacteria highly pathogenic and lethal only to birds.

Through these two themes, we aim to contribute to ensuring food safety and a stable supply of food.

A chicken suffuring from fowl typhoid shows ruffled feathers and lethalgy.
A chicken suffuring from fowl typhoid shows diffuse white necrotic foci in the liver.

List of current research topics

Establishment of measures to reduce contamination of poultry flocks and poultry meat with foodborne pathogens
Elucidation of the pathogenic mechanism of fowl typhoid
Elucidation of the vertical infection mechanism of pullorum disease

Academic degree Ph.D.in Veterinary Sciences
License Veterinarian
Self introduction

I was born in Osaka, but I spent almost half of my life in Towada, Aomori, and now I have come back to Obihiro after 16 years.
Up until now, I have mainly been conducting research on salmonellosis and campylobacteriosis in poultry. In Obihiro, I would like to continue this research and also challenge new research.
My hobbies are work out (currently stopped by Corona) and reading, but I also chopped wood and did DIY for practical use in Towada. I feel very happy when I find a cheap but tasty Italian wine.

Room addressGeneral Research Building 1
Room numberS2102-1
Mail address okamuram atmark obihiro.ac.jp


Research Department/Department of Veterinary Medicine/Division of Veterinary Sciences/Section of Applied Veterinary SciencesOffice for International Accreditation of Veterinary Education/Staff
Related industries Poultry Industry, Animal Health and Public Health, Pharmaceutical products (vaccines etc.) for animals, Food Safety
Affiliated academic society The Japanese Society of Veterinary Science, The Japanese Society on Poultry Diseases, Japanese Society for Bacteriology, Japanese Society of Food Microbiology, Japan Society of Veterinary Epidemiology, Japanese Society of Zoo and Wildlife Medicine
Academic background 1992-1998: BVSc in Kitasato University School of Veterinary Medicine and Animal Sciences
1998-2002: Ph.D. in Osaka Prefecture University Graduate School of Agriculture and Biological Sciences
Mar 2001-Mar 2002: Visiting Scientist in USDA-ARS (Beltville, MD, USA)
Apr 2002-Nov 2002: Postdoc Scientist in USDA-ARS (Beltville, MD, USA)
Dec 2002-Dec 2004: Postdoc in National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinar Medicine
Jan 2005-Dec 2020: Research Associate - Associate Professor in Kitasato University School of Veterinary Medicine
Jan 2021-Present: Professor in Obihiro University of Agriculture and Veterinar Medicine