Population dynamics of capybaras in human-modified landscapes and its relationship with Brazilian spotted fever

• Ano de defesa: 2022
• Autor(a) principal: Lopes, Beatriz
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Hydrochoerus hydrochaeris; Anthropogenic influence; Ecologia populacional; Flutuação populacional; Influências antrópicas; Monitoramento populacional; Population ecology; Population fluctuation; Population monitoring; Zoonoses; Zoonosis
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/91/91131/tde-10052022-115044/

Capybara (Hydrochoerus hydrochaeris) is the main host of Amblyomma sculptum tick, which is the vector of Ricketssia rickettsii bacterium, etiological agent of Brazilian Spotted Fever (BSF), a very lethal disease for humans. Besides being tick hosts, capybaras also amplifies R. rickettsii in the environment through continuous introduction of susceptible animal in population (i.e. young). Previous studies have suggested a causal relationship between capybara population ecology and BSF emergence, since it was found greatest abundances of ticks in BSF-endemic areas than non-endemic and the known role of capybara young as bacterium amplifiers. We aimed to analyze variation in the number of individuals in capybara populations in human-modified landscapes (HMLs), in BSF-endemic (n = 3) and non-endemic areas (n = 4), in São Paulo state, Brazil. We made direct counts of capybaras (from January/2015 to December/2018) to describe population fluctuation and estimate abundance and ecological density indexes. We do not found a typical pattern of fluctuation among surveyed capybara groups. On the contrary, each monitored group showed a particular variation of individuals. The only pattern observed was in the increment of young, which differed in BSF-endemic compared to non-endemic areas. Increment of young occurred earlier in BSF-endemic areas, in July/August, while in BSF-non-endemic areas it occurred after September. We found significantly greater abundance (24 &#177; 14 individuals vs. 12 &#177; 8 individuals) and ecological density indexes (85 &#177; 62 individuals/km2 vs. 33 &#177; 21 individuals/km2) in BSF-endemic than non-endemic areas (P-value < 0.001). This are the first study about population fluctuation of capybaras in HMLs and the first to compare abundance and ecological density indexes between BSF-endemic and non-endemic areas. These information are relevant to better understanding ecological relations between capybaras, ticks, environment and BSF emergence in São Paulo State. Our results reinforce the importance of investigating how HMLs alter capybaras behavior and population, which may influence disease occurrence and spread. Such information are essential to develop strategies and programs of BSF prevention and control.