Mr. Miguel Lourenço (Lisboa / PT), Dr. João Lozano (Lisboa / PT), Ms. Lídia Gomes (Lisboa / PT), Mr. Rui Bernardino (Lisboa / PT), Prof. Dr. Manuela Oliveira (Lisboa / PT), Prof. Dr. Adolfo Paz-Silva (Lugo / ES), Prof. Dr. Luís Madeira de Carvalho (Lisboa / PT)
Abstract text
Introduction: Nematodes of the genus Trichuris are gastrointestinal (GI) parasites of high clinical importance in captive non-human primates (NHPs) kept at zoological institutions, being difficult to control due to anthelminthic drug resistance and eggs" survival in the environment. However, sustainable integrated control approaches are being developed, namely the use of nematophagous fungi.
Objectives: In this study, the ovicidal activity of five native Mucor sp. isolates was tested in vitro against Trichuris sp. eggs.
Materials & methods: A total of five native Mucor sp. isolates (MBB1, MBB2, MDM, ML, and MSM), previously obtained from faecal samples of different NHP groups of the Lisbon Zoo (Portugal), were used in this research. Two different assays were performed: in Petri dishes (PD), and in a faecal microenvironment (FM) model using Hamadryas Baboon faeces containing Trichuris sp. eggs. Control samples with no fungi inoculation were used in both assays. Each sample was observed once or twice a week, on the FM and PD assays, respectively, and isolates ovicidal activity was characterized and quantified, with the proportions of viable and unviable eggs being compared between each isolate and the control group, using the Fisher"s Exact Test (95% confidence). Eggs showing capsule deformation or even rupture, were considered unviable. Both assays lasted three weeks.
Results: In the PD assay, samples inoculated with MBB1, MBB2, MDM, ML, and MSM isolates had ovicidal efficacies of 50%, 0%, 43%, 54%, and 100%, respectively, after three weeks of exposure. Also, at the end of the FM assay, these isolates had efficacies of 14%, 12%, 4%, 14%, and 33%, respectively. All eggs in the control samples remained viable on both assays. Significant differences in eggs" viability were observed for the isolates MBB1, MDM, ML, and MSM on the PD assay, and only for the MSM isolate in the FM assay, in comparison with control.
Conclusion: These results suggest that the use of MSM Mucor sp. strain could provide a valuable complement to the standard deworming practices in NHPs, as an innovative and sustainable integrated approach for GI parasite control.
Funding: This research was funded by CIISA/FMV Project UIDB/00276/2020 and LA/P/0059/2020 - AL4AnimalS (both funded by FCT). Also, João Lozano owns a PhD research fellowship 2020.09037.BD (funded by FCT).