SENSITIVITY OF PARASITIC LOAD DETECTION OF Syphacia spp. IN FECAL SAMPLES FROM MICE BY PCR

• Grant number: 23/07231-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2023
• End date: September 30, 2024
• Field of knowledge: Biological Sciences - Parasitology
• Principal Investigator: Silvia Beatriz Boscardin
• Grantee: Gustavo Vieira Veríssimo Oliveira
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The diagnosis of parasites of the Oxyuridae family is critical for the sanitary control of animals used in research, especially those of the genus Syphacia spp., common in rodents. Examinations considered the 'gold standard' by the Federation of European Laboratory Animal Science Associations (FELASA) involve evaluating the intestinal content of the animal. This procedure has limitations, as it requires the animal to be euthanized and the presence of experienced and well-trained individuals to analyze the samples. Another complementary methodology is the Graham test, which uses adhesive tape to collect samples from the perianal region of the mouse. However, this test can only identify the presence of eggs and cannot visualize adult worms. Recent studies have evaluated diagnostic methods using polymerase chain reaction (PCR), which has shown sensitivity to identify positive samples, even when they are negative using the established method. Additionally, there is no need to euthanize the mouse for sample collection. Data have shown the susceptibility of male, young and immunodeficient mice to Syphacia spp. infection, but there are few studies that evaluate the sensitivity of parasite detection, which may explain false negative results. In this project, the detection sensitivity of Syphacia obvelata and Syphacia muris by PCR will be evaluated using fecal samples from different groups of sentinel mice sent for sanitary control examinations at the Laboratory of Sanitary and Genetic Control (LCS) of the Institute of Biomedical Sciences at USP. The quantity of Syphacia spp. eggs per gram of feces will be determined, and the detection capacity will be evaluated by PCR analysis using serial samples of total DNA extracted from feces.