Parasites as bioindicators of environmental degradation in Latin America: A meta-analysis

Abstract

Unregulated economic growth in Latin America has resulted in environmental degradation, including the release of toxic compounds into the environment. One strategy to understand and prevent the outcomes of this harmful environmental degradation is the use of bioindicators. These are free-living or parasite species that respond to habitat alterations with changes in their numbers, physiology or chemical composition. The aim of this review was to determine whether there is evidence of a significant parasite response to environmental damage in Latin America. We collected 26 papers published between 2003 and 2015 and conducted a meta-analysis to test the null hypothesis that there is no significant overall effect of environmental insults on parasites. The meta-analysis showed a low but still significant negative mean overall effect (Hedges' g = -0.221; 95% CI: -0.241 to -0.200; P < 0.0001). However, the magnitudes and directions of the significant effects varied widely. These results suggest that different groups of parasites have distinct responses to various environmental insults and that the groups should be separately analysed after the accumulation of a sufficient number of studies. For future studies on this topic in Latin America, we suggest: (1) using field and experimental approaches to determine the response of parasites to environmental degradation; (2) using an interdisciplinary approach, including different types of biomarkers in both parasites and individual hosts to generate long-term datasets in polluted and reference areas; (3) conducting studies on parasites as accumulation bioindicators.

Helminth metacommunity structure of wild rodents in a preserved area of the Atlantic Forest, Southeast Brazil

“…Rodents are the most diversified group of mammals (PATTON et al, 2015), may harbor a number of parasites and are reservoirs of several zoonoses (HAN et al, 2015). Helminths may show high biomass indices within a biological community (POULIN, 2007), and can be used as indicators of environmental changes (VIDAL-MARTÍNEZ & WUNDERLICH, 2017). In addition, many helminth species have complex life cycles in which rodents act as intermediate and / or definitive hosts (CHAISIRI et al, 2017).…”

Contracaecum sp. parasitizing Acestrorhynchus lacustris as a bioindicator for metal pollution in the Batalha River, southeast Brazil

“…In addition to currently used indicators, certain parasites have been widely used as bioindicators of accumulation, as environmental pollution significantly affects these organisms (Vidal-Martínez et al, 2009;Vidal-Martínez and Wunderlich, 2016), altering their health and prevalence, distribution, and pathogenicity (Khan and Thulin, 1991;Thielen et al, 2004). Associations between pollutants and parasites can have positive or negative effects depending on the parasite taxa and pollutant type.…”

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“…Table 4 elucidated that the concentration of Fe in P. armata tissues (12.760 µg/gm) was higher than Mn concentration (9.713 µg/gm) and that of Cr (4.903 µg/gm). Large invertebrates and endoparasites were used by some researchers to evaluate water pollution and alterations in In geophysical factors of the aquatic ambiance 44,45 . Other researchers were studying environmental health and anthropogenic impact in particular regions using different parasites as bioindicators 7,36,46 .…”

“…Furthermore, it may refer to the exposure period to such metal 45 . Some researchers were considering that Fish, large invertebrates and endo-parasites are valuable tool for the established guidelines for effective environmental management, and could be used as bio-indicators for evaluating environmental health, environmental alters, and the impact of anthropogenic activities) 7,12,18,36 .…”