Epigenetic Mechanisms Associated with Endocrine Disrupting Chemicals (pesticides, antibiotics, metals) used in Vietnam, Ecuador and other Shrimp-Producing Countries - Are They Associated with Acute Hepatopancreatic Necrosis Disease (AHPND)?

Crop protection chemicals are commonlyused in agricultural farming systems. In some countries, legal chemicals used for plant protection on market must be permitted bylocal Ministries of Agriculture or other agencies, some of which announce annual lists which include product names, ingredients and producers/distributors and effects on plants.The popular crop protection chemical groups include: pesticides, disease treatment in plants, herbicides, rodenticides, growth stimulus, insect allure and snail killers. Pesticides, disease treatment in plants and herbicides are the most priority groups and have trended increasingly, withsome pesticides used mainly to protect the rice and banana fields in inlands areas or integrated rice-shrimp and banana-shrimp areas.The permitted chemicals for plant protection includeseveral commercial formulations containing the herbicide and antibiotic Glyphosate(Roundup, etc.) used to produce the GM-based crops such as soybeans and corn used in aquafeeds. Glyphosate, patented as a strong broad spectrum bactericide, is also achelator, hormone-disruptor chemical (EDC) and class 2 carcinogen according to the WHO.As part of the ‘ONE HEALTH Epigenomics Educational Initiative’that includethe shrimpENCODE and mangroveENCODE projects, we study the interactive health effects of global climate change and pollution on marine microbes and animals. We are concerned about emerging bacterial diseases of shrimp such as AHPND and antibiotic resistance (AR).

AHPND is caused by Vibrio parahaemolyticus(Vp) strains containing a plasmid with a transposon flanking the Photorhabdus-like insecticidal toxins PirA and PirB that is weakly similar to endotoxinfrom Bacillus thuringiensis (Bt).Loss of resistance to the herbicide Glyphosate in plants is associated with amplification of transposon-containing resistance gene. Susceptibility to AHPND may involve epigenetic mechanismssuch as DNA transposition via horizontal gene transfer (HGT) of bacterial genes such astransposases and others,DNA methylation, chromatin modifications, and non-coding RNAs (https://www.was.org/meetingabstracts/ShowAbstract.aspx?Id=32080). Though there is evidence for interaction of Vibrio cholera with Glyphosate, no research has been published on health considerations regardinghorizontal transfer (HGT) of microbial transgenes (Bt), or Glyphosate-relatedAR genes,on non-target organisms such as shrimp.Wehypothesize that AHPND is an epigenetic disease caused by epigenetic changes induced by the interaction of the shrimp genome with environmental stressors [EDCs, feed ingredientsand bacterial communities] present in the sediment of shrimp ponds and mangroves wetlands.We will present preliminary information about (a) the chemicals used since 2010 in Vietnam and other shrimp-producing countries from Southeast Asia, Latin America and Africa, and (b)the epigenetic mechanisms associated with some of these chemicals. Epigenetic mechanisms associated with EDCs included among others: DNA methylation (Methoxychlor, Vinclozoin, DDT, DDE, BHC, Chlordane, PCBs, Arsenic), Histone modifications (Paraquat, Dieldrin, Propoxur), microRNA expression (Dichlorvos, Fipronil, Triazophos, Triadimefon, Propiconazole, Myclobutanil, Arsenic), and DNA transposition of mobile/transposable elementsfrom bacteria (heavy metals).