# 2000–2025: A Quarter of a Century of Studies on Pet Ownership in the Amazon—Epidemiological Implications for Public Health

## TL;DR

This study reviews 25 years of research on zoonotic pathogens in pets in the Amazon, highlighting gaps and the need for better surveillance to reduce disease risks.

## Contribution

The paper provides a systematic review of zoonotic pathogens in Amazonian companion animals, revealing geographic and methodological biases.

## Key findings

- Parasitic infections like Leishmania spp. and Toxoplasma gondii are most commonly reported in Amazonian companion animals.
- Research is concentrated in Brazil and the western Amazon, leaving much of the Basin understudied.
- Current studies often use limited methodologies, such as cross-sectional designs and serology-based diagnostics.

## Abstract

Anthropogenic pressures in the Amazon Basin are reshaping human–animal–environment interactions and increasing zoonotic disease risk. Within this One Health context, domestic dogs and cats are underrecognized contributors to pathogen circulation at the human–wildlife interface. We conducted a PRISMA-compliant systematic review of zoonotic pathogens reported in companion animals across Amazonian territories in nine countries, including literature published between 2000 and 2025 in four languages. Zoonotic pathogens showed a heterogeneous yet widespread distribution, with parasitic infections, particularly Leishmania spp., Toxoplasma gondii, and vector-borne protozoa, being the most frequently reported. A pronounced geographic bias was evident, with studies concentrated in Brazil and selected areas of the western Amazon, while large portions of the Basin remain understudied. Methodological limitations included reliance on cross-sectional designs and heterogeneous diagnostic approaches, often based solely on serology. These findings highlight the need to strengthen One Health-oriented governance frameworks that integrate animal health surveillance into environmental and public health policies. Priority actions include expanding surveillance to underrepresented regions, harmonizing diagnostic protocols, investing in regional laboratory capacity, and promoting community-based monitoring. Strengthened cross-sectoral and transboundary coordination is essential to reduce zoonotic risk and support evidence-based disease prevention in Amazonian ecosystems.