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Document type: Trabalho de Conclusão de Curso
Access type: Acesso Embargado
Embargo Date: 2024-08-12
Title: Infection of mice with a Brazilian clinical isolate of Mayaro virus results in mild disease
Author: Tanaka, Camila Ayumi
First Advisor: Mineo, Tiago Wilson Patriarca
First coorientator: Rosa, Rafael Borges
First member of the Committee: Silva, Murilo Vieira da
Second member of the Committee: Santos, Igor de Andrade
Summary: Background: Mayaro virus (MAYV) is the etiologic agent of Mayaro fever and is currently considered an emergent and neglected disease. Several factors indicate the possibility of urbanization of this virus that may configure the disease as a major public health problem. Cases of Mayaro fever have been confirmed in different Brazilian states, which supports the possible adaptation of the vector to the urban environment. The characterization of the Brazilian isolate of Mayaro virus (MT/SINOP/210/2011) in a murine model may help in the elucidation of disease mechanisms, pathogenesis, and contribute to advancing the development of treatments and prophylactic measures. Methods: IFN-α/β receptor-deficient (B6.129S2-Ifnar1) or congenital controls (129Sv/Ev) female and male mice at 21 days of age were inoculated via footpad with 105 TCID50 of MAYV or PBS in a volume of 20 μL. Survival, body weight, and paw edema were assessed daily. A clinical score was determined using a numerical value and employed in phenotypic disease monitoring. Three and six days after infection, blood, joints, and muscles were collected for hematology and histopathology evaluation, respectively. Findings: Knockout mice were susceptible to infection, developing clinical signs of the disease, which was not observed in animals with an intact immune system. There were no changes in the animals' body weights and the score evaluation demonstrated that infected male mice showed more pronounced clinical signs compared to females, such as diarrhea, purulent conjunctivitis, and plantar cushion edema. MAYV infection in knockout mice led to a low lethality rate. Histopathological analysis revealed that there was a greater inflammatory response in the acute phase of the disease in infected knockout animals compared to wild-type animals. Mild edema and vasculitis were seen in both knockout and wild-type animals. Finally, there was an intense cellular infiltrate of lymphocytes in the acute phase of the disease in knockout and wild-type. Interpretation: The infected knockout animals showed mild clinical signs of the disease. The infection had a benign course and most were able to control the infection. The signs observed lasted only a few days, coinciding with the period of the acute phase of Mayaro fever in humans, therefore, the disease manifests itself mildly in humans and mice, demonstrating that the circulating strain MT/SINOP/210/2011 has low virulence and the experimental model is compatible with the course of infection in human patients.
Keywords: Mayaro
Experimental model
Public health
Language: eng
Country: Brasil
Publisher: Universidade Federal de Uberlândia
Quote: TANAKA, Camila Ayumi. Infection of mice with a Brazilian clinical isolate of Mayaro virus results in mild disease. 2022. 14 f. Trabalho de Conclusão de Curso (Graduação em Biomedicina) – Universidade Federal de Uberlândia, Uberlândia, 2022.
Date of defense: 12-Aug-2022
Appears in Collections:TCC - Ciências Biomédicas

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