‘Mosca de la bichera’ or simply ‘bichera’ are common names given in Uruguay and the region to the primary myiasis-causing species Cochliomyia hominivorax, the New World Screwworm (NWS) fly (Diptera: Calliphoridae). Myiasis happens when dipteran larvae infest live animals at least during some developmental phase to feed on host’s flesh and fluids. For the NWS fly it is mandatory that all three larvae phases develop on living tissues of warm-blooded vertebrates, including humans. Unsurprisingly, this parasitic behavior causes great profit losses to the livestock industry and is also considered a neglected public health issue. NWS is endemic from the tropics and subtropics of the Americas, but has been eradicated from North and Central America through a Sterile Insect Technique (SIT) based Area Wide – Integrated Pest Management (AW-IPM) program that lasted more than 50 years. Since 2004, a permanent barrier is actively maintained in Darien, along the Panama-Colombian border, by releasing 14 million sterile flies per week to avoid reintroductions. Due to its direct and indirect impact on the national economy, the logistic complexity and the cost of SIT control programs, much discussion is underway in Uruguay about NWS fly eradication. Direct economic losses due to myiasis in Uruguay oscillate between USD 40 and 154 million annually (i.e., between 2-8% of livestock Gross Domestic Product, GDP). Currently, the Food and Agriculture Organization of the UN/International Atomic Energy Agency (FAO/IAEA) and the US Department of Agriculture/Panama United States Commission for the Eradication and Prevention of Screwworm/ Ministry of Livestock, Agriculture and Fisheries (USDA/COPEG/MGAP) have been working on eradication proposals for Uruguay. Cost-benefit analysis of each group concluded that a net present value of around USD 98 million and USD 146 million could be achieved, respectively, supporting the positive impact of NWS fly eradication at local farmers and the whole livestock sector levels. The main challenge of this endeavor is to find a way to keep the myiasis-free status of Uruguay in case that its neighbors, Argentina and Brazil, do not engage in a similar program, at least for their southernmost region. Here we review the bulk of bibliography produced since the beginning of NWS eradication programs in North America during the 40s decade, its life cycle and parasitic lifestyle as well as many aspects of its population genetics and ecology. We further discuss promising biotechnological approaches under active development based on transgenesis and CRISPR/Cas genome-editing, that are considered the new avenue in insect-control strategies. Balance among innovation and regulation framework is considered based on lessons learned. Currently, a CRISPR/Cas gene editing strategy for gene drive is being investigated in Uruguay, a development conducted with national funds, what guarantees its complete control and local institutions, authorities and ultimately livestock producers can be the biotechnology owners. Finally, we highlight the know-how that will be generated opening the possibility to locally develop new genetic-based control strategies for other parasites and/or vector insects of high veterinary and public health relevance.

Aim: We report the synthesis and biological evaluation of a small library of 15 functionalized 3-styryl-2-pyrazolines and pyrazoles, derived from curcuminoids, as trypanosomicidal agents. Methods &...

Rhipicephalus microplus, the “common cattle tick”, is the most important ectoparasite in livestock worldwide due to the economic and health losses it produces. This tick is a vector for pathogens of several tick-borne diseases. In Latin American countries, damages reach approximately USD 500 million annually due to tick infections, as well as tick-borne diseases. Currently, resistant populations for every chemical group of acaricides have been reported, posing a serious problem for tick control. This study aims to find new alternatives for controlling resistant ticks with compounds derived from small synthetic organic molecules and natural origins. Using BME26 embryonic cells, we performed phenotypic screening of 44 natural extracts from 10 Mexican plants used in traditional medicine, and 33 compounds selected from our chemical collection. We found 10 extracts and 13 compounds that inhibited cell growth by 50% at 50 µg/mL and 100 µM, respectively; the dose-response profile of two of them was characterized, and these compounds were assayed in vitro against different life stages of Rhipicephalus microplus. We also performed a target-directed screening of the activity of triosephosphate isomerase, using 86 compounds selected from our chemical collection. In this collection, we found the most potent and selective inhibitor of tick triosephosphate isomerase reported until now. Two other compounds had a potent acaricidal effect in vitro using adults and larvae when compared with other acaricides such as ivermectin and Amitraz. Those compounds were also selective to the ticks compared with the cytotoxicity in mammalian cells like macrophages or bovine spermatozoids. They also had a good toxicological profile, resulting in promising acaricidal compounds for tick control in cattle raising.