Karen H Tonooka

Dr. Karen H Tonooka


Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 September 2023 in Pathogens
Verified
Journal Article
Open access
PDF file
HOHedmon Okella
Hedmon Okella
KTKaren H Tonooka
Karen H Tonooka
EOEmmanuel Okello
Emmanuel Okello
Early detection of Mycoplasmal mastitis is greatly hampered by late seroconversion, slow growth of Mycoplasma organisms, intermittent shedding, and the high cost of diagnostic tests. To improve future diagnostic development, examining the available techniques is necessary. Accordingly, the present study systematically reviewed M. bovis diagnostic studies published between January 2000 and April 2023 utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol. The protocol registration was performed according to the Open Science Framework (osf.io/ug79h), and the electronic search was conducted in the World Catalog, Mendeley, ProQuest, ScienceDirect, Semantic Scholar, PubMed, Google Scholar, Prime Scholar, and PubMed Central databases using a Boolean operator and inclusion and exclusion criteria. Of the 1194 pieces of literature retrieved, 67 studies were included. Four broad categories of up to 16 diagnostic approaches were reported: microbial culture, serological, DNA-based, and mass spectrometry. Overall, DNA-based techniques were the most published (48.0%), with recombinase polymerase amplification (RPA) and loop-mediated isothermal amplification (LAMP) as the most promising user-friendly, equipment-free techniques. On the other hand, mass spectrometry was reported as the least utilized (2.9%) given the high equipment cost. Though costly and laboratory-allied, DNA-based techniques, particularly PCRs, were reported as the most rapid and specific approach.

15 July 2022 in Antibiotics
Verified
Journal Article
Open access
PDF file
Sharif S. AlySharif S. Aly
Sharif S. Aly
EOEmmanuel Okello
Emmanuel Okello
WAGDY RADY ELASHMAWY ELASHMAWYWAGDY RADY ELASHMAWY ELASHMAWY
WAGDY RADY ELASHMAWY ELASHMAWY
DWDeniece R Williams
Deniece R Williams
RARandall J. Anderson
Randall J. Anderson
TLTerry Wayne Lehenbauer
Terry Wayne Lehenbauer
Intramammary antibiotic (AB) and internal teat sealants (TS) infusion at dry-off have been used to prevent intramammary infections (IMI) in dairy cows during the dry period and reduce the risk of mastitis during the dry period and subsequent lactation. A randomized clinal trial was completed on eight California dairy herds to estimate the effects of different dry cow therapies (AB, TS, AB + TS or None) on clinical mastitis and culling. A total of 1273 cows were randomized to one of the four treatment groups over summer and winter seasons. For each enrolled cow, microbiological testing was done on quarter milk samples collected from the first detection of clinical mastitis within the first 150 days in milk (DIM) in the subsequent lactation. Statistical analysis was done using generalized linear mixed models. There were no significant differences in the odds of clinical mastitis or culling between cows treated with AB, TS, or AB + TS compared to the controls. Dry cow therapy with AB and/or TS had no statistically significant effect on clinical mastitis and cow culling during the first 150 DIM.

21 June 2025 in Veterinary Sciences
Verified
Journal Article
Open access
PDF file
Daniela R. BrunoDaniela R. Bruno
Daniela R. Bruno
KTKaren H Tonooka
Karen H Tonooka
TLTerry Wayne Lehenbauer
Terry Wayne Lehenbauer
Sharif S. AlySharif S. Aly
Sharif S. Aly
WAGDY RADY ELASHMAWY ELASHMAWYWAGDY RADY ELASHMAWY ELASHMAWY
WAGDY RADY ELASHMAWY ELASHMAWY
Bovine mastitis is a significant disease affecting dairy cattle worldwide, impacting milk quality and farm profitability. Understanding pathogen distribution is crucial for effective disease management. This study analyzed 319,634 individual cow milk samples submitted to the UC Davis Milk Quality Laboratory between 2009 and 2023 to assess pathogen prevalence, seasonal variations, and long-term trends. Routine microbiological cultures identified major and minor mastitis pathogens, with additional testing for Mycoplasma spp. Statistical analyses evaluated annual and seasonal trends in bacterial isolation rates. Results indicated that environmental pathogens, particularly non-aureus staphylococci and coliforms, were most frequently isolated, while contagious pathogens (Staphylococcus aureus, Streptococcus agalactiae, and Mycoplasma spp.) were less prevalent. Seasonal trends revealed higher contamination rates in Winter and increased no-growth samples in Summer. The study also observed a decline in sample submissions in recent years, possibly reflecting evolving dairy management practices. These findings provide a comprehensive perspective on mastitis pathogen dynamics in California’s Central Valley, supporting improved milk quality control measures and tailored mastitis prevention strategies.