THE ABSENCE OF PARASITES: A HEALTH SIGN OR AN ALERT OF ECOLOGICAL DEGRADATION?

Abstract

In aquatic ecosystems, bioindicators are essential to detect and prevent environmental impacts that threaten the integrity of habitats, and parasites, although often neglected, are an important group in this context. This study investigated parasites of the fish species Oreochromis niloticus as indicators of environmental health in urban streams in Porto Velho, RO, Brazil, with samples collected between 2022 and 2024. The results showed the absence of adult parasites in the muscles of the fish, but a high presence of eggs and larvae of parasites common in humans, indicating a polluted and unbalanced aquatic environment, possibly due to human activities and inadequate sanitation. Interviews with residents revealed that 48% consume or know someone who consumes fish from these streams, increasing the risks to public health. This highlights the need for continuous environmental monitoring and integrated approaches to water resources management. The absence of parasites, although it may seem positive, is a sign of ecosystem compromise, requiring urgent interventions to improve sanitation conditions and implement effective public policies. Parasite diversity must be considered in monitoring, as it provides perspectives on ecological changes and anthropogenic impacts, essential for the sustainability of aquatic ecosystems and the protection of public health.