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Inactivation of Pythium insidiosum by ozone gas: effect of dose and time of exposure

Grant number: 19/15532-4
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): January 01, 2020
Effective date (End): December 31, 2020
Field of knowledge:Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
Principal Investigator:Jair Camargo Ferreira
Grantee:Viviani Silva Rodrigues
Home Institution: Pró-Reitoria Adjunta de Pesquisa e Pós-Graduação. Universidade de Franca (UNIFRAN). Franca , SP, Brazil


The main goal of the present study is to describe the effect of dose and exposure time of ozone (O3) gas on the viability of Pythium insidiosum isolated from horses. In Experiment 1, pre-cultured aliquots of the pathogen will be divided into four groups according to the O3 concentration of each treatment: 72, 52, 32 or 0 ¼g O3 mL-1 (n = 5 aliquots/group). The aliquots will be exposed to the respective treatments for 30 minutes each. In Experiment 2, additional aliquots will be divided into three groups according to the time of exposure to the O3 gas (72 ¼g O3 mL-1): 05, 15 or 30 minutes. In both experiments, treatments will be performed every 24 hours for three consecutive days. At the end of the third treatment, all aliquots will be incubated at 35 °C for four weeks. The parameters to be evaluated during the post-treatment period are: a) Inhibition of growth rate, b) germicidal/germistatic action of each therapy, and c) changes in the superficial architecture of P. insidiosum. The characterization of the effect of doses and time of exposure to O3 will be essential to establish the best therapeutic protocol for the inactivation of P. insidiosum in horses. Additionally, our findings will support future studies aiming the treatment of pythiosis in multiple species, including humans.