Long term effects of carbaryl exposure on antiviral immune responses in Xenopus laevis

Abstract

Water pollutants associated with agriculture may contribute to the increased prevalence of infectious diseases caused by ranaviruses. We have established the amphibian Xenopus laevis and the ranavirus Frog Virus 3 (FV3) as a reliable experimental platform for evaluating the effects of common waterborne pollutants, such as the insecticide carbaryl. Following 3 weeks of exposure to 10 ppb carbaryl, X. laevis tadpoles exhibited a marked increase in mortality and accelerated development. Exposure at lower concentrations (0.1 and 1.0 ppb) was not toxic, but it impaired tadpole innate antiviral immune responses, as evidenced by significantly decreased TNF-α, IL-1β, IFN-I, and IFN-III gene expression. The defect in IFN-I and IL-1β gene expression levels persisted after metamorphosis in froglets, whereas only IFN-I gene expression in response to FV3 was attenuated when carbaryl exposure was performed at the adult stage. These findings suggest that the agriculture-associated carabaryl exposure at low but ecologically–relevant concentrations has the potential to induce long term alterations in host-pathogen interactions and antiviral immunity.

Effects of low doses Trichlorfon exposure on Rana chensinensis tadpoles

“…The results are consistent with those of other studies showing adverse effects in various amphibians. Interestingly, 10 μg/L carbaryl exhibited a marked increase in mortality and accelerated development in Xenopus laevis , whereas a significant death . These results were accordance with the results that exposure exerts an effect on the thyroid axis by decreasing levels of thyroid hormone (T3) in amphibians, which disrupted the endocrine activities .…”

“…The adverse effects of pesticides on amphibians, especially larvae, should therefore be investigated in aquatic ecological risk assessments. Previous studies have stressed that the tadpoles can be used as reference organisms in assessing the risk effects induced by several emerging pollutants, including agrochemicals …”

Xenopus-FV3 host-pathogen interactions and immune evasion

“…The increased susceptibility of previously infected, but apparently healthy, adults frogs to reactivated FV3 infection suggests that conditions altering the immune status such as stress or pollution can contribute to the dissemination of emerging ranavirus infections. In this regard, we have reported that exposure during early development of tadpoles to water contaminants including the herbicide atrazine and the insecticide carbaryl, even at very low subtoxic doses, induces long lasting defect of antiviral immunity that persists into adults (De Jesus Andino et al, 2017; Sifkarovski et al, 2014). For example, exposure of tadpoles for only 3 weeks to low (0.1 and 1.0 ppb) subtoxic concentrations of carbaryl induced long lasting defects of expression response of pro-inflammatory (IL-1β) and antiviral type I interferon (IFN) genes persisting after metamorphosis (De Jesus Andino et al, 2017).…”

“…In this regard, we have reported that exposure during early development of tadpoles to water contaminants including the herbicide atrazine and the insecticide carbaryl, even at very low subtoxic doses, induces long lasting defect of antiviral immunity that persists into adults (De Jesus Andino et al, 2017; Sifkarovski et al, 2014). For example, exposure of tadpoles for only 3 weeks to low (0.1 and 1.0 ppb) subtoxic concentrations of carbaryl induced long lasting defects of expression response of pro-inflammatory (IL-1β) and antiviral type I interferon (IFN) genes persisting after metamorphosis (De Jesus Andino et al, 2017). This was accompanied by a significant increase in viral loads in infected tissues of young adult frogs several months after being exposed to the contaminant.…”

Various Methods for Removal, Treatment, and Detection of Emerging Water Contaminants

“…EDCs are defined by the World Health Organization (WHO) as chemicals that may alter the reproductive function in males and females, increase incidence of breast cancer, abnormal growth patterns, and neurodevelopmental delays in children as well as changes in immune function [17]. EDCs include natural hormones created in the body or synthetic hormones as well as industrial/commercial compounds which can have some hormonal functions, such as pharmaceuticals and personal care products (PPCPs) [18][19][20], pesticides [21][22][23], plasticizers [24,25], nanoparticles [26,27], and so on.…”