Simulation of the transmission dynamics of sporotrichosis in cats using the SI epidemiological model

Sporotrichosis is an emerging and neglected mycosis with a worldwide distribution. In Brazil, a zoonotic epidemic is occurring, with two epicenters identified in the states of Rio de Janeiro and Rio Grande do Sul. However, little is known about the dynamics of this epidemic. In the present work, the incidence rate of the disease was calculated, and the SI (Susceptible Infected) mathematical model was employed to elucidate the epidemiological parameters and the epidemic curve of sporotrichosis in cats. Data from the urban area of Pelotas, the main city affected by sporotrichosis in southern Brazil, and secondary data from the main veterinary mycological diagnostic laboratory in the region were utilized. Through the results obtained, an average incidence rate of 79 cases per 100,000 cats was found, and R0 of 1.45 (basic reproduction number) was determined, indicating that the epidemic is in its exponential phase. It was confirmed that the SI mathematical model was capable of inferring fundamental parameters of the dynamics and dissemination of sporotrichosis, and can be used as a tool for predicting the progression of this disease. As a consequence of the results found, we present an epidemiological scenario that necessitates immediate intervention with measures to contain the spread of this epidemic.