Assessment of tick populations associated with capybaras in natural and anthropized environments with presence or absence of invasive plants in São Paulo state

• Grant number: 22/14632-8
• Support Opportunities: Scholarships in Brazil - Master
• Effective date (Start): June 01, 2023
• Effective date (End): May 31, 2025
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal Investigator: Marcelo Bahia Labruna
• Grantee: Matheus Pasini Martins
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

This project is directly linked to a FAPESP Research Grant (process 2021/02976-1) within the UKRI/NERC/FAPESP Cooperation Agreement between researchers from the UK and the state of São Paulo, with a focus on researching the impacts caused by invasive species on human disease vectors, through analyses based on community and ecosystem ecology. Invasive plants can cause wide-ranging ecological impacts at different scales on natural communities and affect functions fundamental to the conservation of ecosystem services. In southeastern Brazil, invasive herbaceous plants such as marsh lily (Hedychium coronarium) and elephant grass (Cenchrus purpureus) can alter the diversity of native species in riparian areas, as well as the distribution and abundance of capybaras (Hydrochoerus hydrochaeris), by providing habitat for refuge and resting, and potentially food. Capybaras usually carry ticks, among them Amblyomma sculptum, vector of the Rickettsia rickettsii bacteria, which causes spotted fever (FMB). Thus, invasive plants have the potential to increase the risk of FMB in invaded areas. However, quantitative and qualitative information describing the intensity of these interactions involving invasive plants, capybaras, and ticks is lacking. Understanding these dynamics will be critical to understanding the spatiotemporal patterns of tick-borne disease risk in this region. Thus, the overall objective of this project is to describe and understand the putative invasive plant-capybara-tick system in São Paulo state, which will serve as a basis for future investigations and predictions of human health risk posed by this system and its component species. For this, the populations of ticks associated with capybaras (A. sculptum and Amblyomma dubitatum) will be quantified in at least 30 environments with presence of capybaras, 10 in natural areas (Natural Parks of the state of São Paulo) and 20 in anthropized areas. The latter will be divided into 10 endemic areas for spotted fever and 10 non-endemic areas. In each of the 30 areas, we will collect and quantify ticks using dry ice traps and flannel dragging to collect larvae, nymphs and adults. Collections will be made specifically in the habitat of capybaras, including, when present, the vegetation cover dominated by marsh lily (H. coronarium) and elephant grass (C. purpureus). The results will be evaluated quantitatively and comparatively taking into account the tick species (A. sculptum and A. dubitatum), the type of vegetation cover (H. coronarium, C. purpureus and others) and the type of environment (natural, anthropized endemic, anthropized non-endemic). It is hoped that the results can provide information on the role of the invasive plants in question on human health risk with regard to ticks and spotted fever.