Drug resistance in parasitic helminths of veterinary importance in Chile: status review and research needs

The increasing development of anthelmintic resistance (AR) in parasites of livestock is threatening animal health and production worldwide. In Chile, studies evaluating the field efficacy of anthelmintics and the detection of AR have been performed since the 2000s, but until now, no previous attempt has tried to systematise the available information. This article reviews general concepts about AR in helminths of veterinary importance, methods for diagnosis of AR and summarises the published reports of AR in Chile. Anthelmintic resistance in Chile has been reported in gastrointestinal nematodes of horses (benzimidazole resistance) and ruminants (sheep and cattle, macrocyclic lactone and benzimidazole resistance). However, these cases involved a limited number of selected farms and no further conclusions can be made of the status of parasite drug resistance at a regional or national level. No published cases of AR in Fasciola hepatica have been reported in Chilean livestock, but human infections with triclabendazole-resistant F. hepatica have been described in patients with previous consumption of watercress or untreated water from marshes grazed by livestock. Given the zoonotic potential and endemic nature of F. hepatica in Chile, it is urgent to determine the extent of liver fluke resistance. Current research gaps of the situation of AR in Chile and suggestions for the performance of laboratory and field studies are further discussed

EL DERECHO AMBIENTAL INTERNACIONAL Y LOS SERVICIOS ECOSISTÉMICOS BOSCOSOS SECOS: REFLEXIONES DESDE LA LÓGICA Y ÉTICA JURÍDICA

INTERNATIONAL ENVIRONMENTAL LAW AND DRY FORESTED ECOSYSTEM SERVICES: REFLECTIONS FROM LOGIC AND LEGAL ETHICS RESUMEN En este trabajo abordamos desde la doctrina jurídica y filosófica, las contradicciones hombre-naturaleza, el problema ecológico reflejado en los conceptos contenidos en los instrumentos internacionales sobre el tema. A su vez examinamos los problemas de la dialéctica del pensamiento a través de la ética y la lógica jurídica, las cuales aportan indisolublemente a la doctrina del Derecho Ambiental Internacional. Como métodos fundamentales se utilizan el exegético-analítico, para determinar el sentido y alcance de las normativas vigentes en la materia; el doctrinal en correlación con el análisis de la legislación vigente, para verificar la necesidad de su perfeccionamiento; el histórico, para abundar en los antecedentes, el contexto y formación de las doctrinas normativas y jusfilosóficas que le sirven de fundamento; y finalmente el de Derecho Comparado, que permitió conocer el tratamiento jurídico que dan otros sistemas de Derecho a una realidad similar. PALABRAS CLAVE: Lógica jurídica; ética jurídica; derecho ambiental internacional; ecosistemas boscosos. ABSTRACT In this work we approach from the juridical and philosophical doctrine, the man-nature contradictions, the ecological problem reflected in the concepts contained in the international instruments on the subject. At the same time, we examine the problems of the dialectic of thought through ethics and legal logic, which indissolubly contribute to the doctrine of International Environmental Law. As fundamental methods, the exegetical-analytical method is used to determine the meaning and scope of the regulations in force in the matter; the doctrinal one in correlation with the analysis of the current legislation, to verify the need for its improvement; the historical one, to abound in the antecedents, the context and formation of the normative and iusophosophical doctrines that serve as its foundation; and finally that of Comparative Law, which allowed us to know the legal treatment given by other systems of Law to a similar reality. KEYWORDS: Legal logic; legal ethics; international environmental law; forest ecosystems

Feeding chicory (Cichorium intybus) selectively reduces Ostertagia ostertagi infection levels in cattle

Objectives: Studies were conducted to test the potential use of chicory against gastrointestinal nematode infections in cattle. Methods: In study 1, fifteen 2-4 months-old dairy calves were allocated into a chicory (CHI, n=9) or control (CTL, n=6) group. CHI and CTL were stabled and fed with chicory silage or hay, resp., ad lib for 56 days. Protein/energy intakes were equalized between groups throughout the study. After 14 days on the diet all calves were infected with 10,000 Ostertagia ostertagi and 66,000 Cooperia oncophora third-stage (L3) larvae. In study 2, twenty 4-6 months-old dairy calves grazed a second-year, pure chicory sward (CHI, n=10) or a ryegrass/white clover pasture (CTL, n=10) for 43 days. After 7 days on the diet all calves were infected with 20,000 O. ostertagi L3. In both studies, individual live weights were recorded and faecal egg counts were calculated as number of eggs per g of dried feces (FECDM). At day 56 (study 1) calves were killed for worm recovery. Live weights and log-transformed FECDM were analysed by ANOVA using repeated measurements. Log-transformed worm counts were analysed by t-test. Results: In study 1 daily live weight gains were 500 and 329 g/day in CHI and CTL animals, resp. (p=0.02). Mean FECDM were not significantly different between groups (p=0.19). O. ostertagi geo mean worm counts were 1599 (± 296) and 3752 (± 258) in CHI and CTL groups, resp. (p0.05). From this point, egg excretion in CHI calves was significantly reduced and by day 36 post-infection FECDM was decreased by 48-65% compared to CTL (P<0.05). Discussion: Feeding on a chicory diet demonstrated a marked anthelmintic effect against O. ostertagi in both trials, whereas C. oncophora in study 1 was unaffected. Apparently, chicory does not interfere with worm establishment of O. ostertagi but significantly reduces egg excretion and adult worm counts. The lower weight gains in study 2 probably reflect lower energy consumption in this group and suggest that duration of grazing of pure chicory should be limited to selectively target established O. ostertagi adult populations

Antiparasitic activity of chicory (Cichorium intybus) and its natural bioactive compounds in livestock: a review

Increasing drug resistance in gastrointestinal (GI) parasites of livestock and concerns about chemical residues in animal products and the environment are driving the development of alternative control strategies that are less reliant on the use of synthetic drugs. An increasingly investigated approach is the use of bioactive forages with antiparasitic properties as part of the animal’s diet (nutraceuticals) or as potential sources of novel, natural parasiticides. Chicory (Cichorium intybus) is a multi-purpose crop and one of the most promising bioactive forages in temperate regions, and numerous in vivo trials have explored its potential against parasitic nematodes in livestock. However, it is unclear whether chicory can induce a direct and broad activity against various GI parasites in different livestock species, and the levels of chicory in the diet that are required to exert an efficient antiparasitic effect. Moreover, the mechanisms leading to the reported parasiticidal activity of chicory are still largely unknown, and its bioactive phytochemicals have only recently been investigated. In this review, we summarise the progress in the study of the antiparasitic activity of chicory and its natural bioactive compounds against GI parasites in livestock, through examination of the published literature. The available evidence indicates that feeding chicory can reduce faecal egg counts and/or worm burdens of abomasal nematodes, but not infections with intestinal worms, in ruminants. Highly chicory-rich diets (≥ 70% of chicory dry matter in the diet) may be necessary to directly affect abomasal parasitism. Chicory is known to synthesise several bioactive compounds with potential antiparasitic activity, but most research has been devoted to the role of sesquiterpene lactones (SL). Recent in vitro studies have confirmed direct and potent activity of SL-rich extracts from chicory against different GI helminths of livestock. Chicory SL have also been reported to exhibit antimalarial properties and its potential antiprotozoal activity in livestock remains to be evaluated. Furthermore, the detailed identification of the main antiparasitic metabolites of chicory and their pharmacokinetics need further confirmation. Research gaps and perspectives on the potential use of chicory as a nutraceutical forage and a source of bioactive compounds for parasite control in livestock are discussed

Exposition von Bio-Milchvieh gegenüber dem Labmagenwurm Ostertagia ostertagi durch Messung von Antikörpertitern in Tankmilch: vorläufige Ergebnisse in Österreich

Wir untersuchten die Exposition von Bio-Milchvieh gegenüber O. ostertagi in Österreich durch Messung von parasitenspezifischer Antikörper in Tankmilch. Es wurde eine hohe Parasiten-Exposition bestätigt, was ein Monitoring und die Einführung nachhaltiger, lokal relevanten Kontrolle rechtfertigt

Bio-Guided Fractionation and Molecular Networking Reveal Fatty Acids to Be Principal Anti-Parasitic Compounds in Nordic Seaweeds

Copyright © 2021 Bonde, Bornancin, Lu, Simonsen, Martínez-Valladares, Peña- Espinoza, Mejer, Williams and Thamsborg. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.[EN]Widespread use of antimicrobial drugs has led to high levels of drug-resistance in pathogen populations and a need for novel sources of anti-bacterial and anti-parasitic compounds. Macroalgae (seaweed) are potentially a rich source of bioactive compounds, and several species have traditionally been used as vermifuges. Here, we investigated the anti-parasitic properties of four common cold-water Nordic seaweeds; Palmaria palmata (Rhodophyta), Laminaria digitata, Saccharina latissima and Ascophyllum nodosum (Ochrophyta, Phaeophyceae). Screening of organic extracts against helminths of swine (Ascaris suum) and sheep (Teladorsagia circumcincta) revealed that S. latissima and L. digitata had particularly high biological activity. A combination of molecular networking and bio-guided fractionation led to the isolation of six compounds from extracts of these two species identified in both fermented and non-fermented samples. The six isolated compounds were tentatively identified by using MS-FINDER as five fatty acids and one monoglyceride: Stearidonic acid (1), Eicosapentaenoic acid (2), Alpha-Linolenic acid (3), Docosahexaenoic acid (4), Arachidonic acid (5), and Monoacylglycerol (MG 20:5) (6). Individual compounds showed only modest activity against A. suum, but a clear synergistic effect was apparent when selected compounds were tested in combination. Collectively, our data reveal that fatty acids may have a previously unappreciated role as natural anti-parasitic compounds, which suggests that seaweed products may represent a viable option for control of intestinal helminth infections.SIThis project was funded by the Green Development and Demonstration Program (GUDP) (Project No. 34009–17–1220). In vitro studies performed on T. circumcincta was funded by Short Term Scientific Mission (STSM) Grant provided by European Cooperation in Science and Technology (COST CA16230 - Combatting anthelmintic resistance in ruminants). MM-V funded by the Spanish “Ramon y Cajal” Program (Ministerio de Economía y Competitividad; MM-V, RYC-2015–18368)

Identification of compounds responsible for the anthelmintic effects of chicory (Cichorium intybus) by molecular networking and bio-guided fractionation

[EN] Increasing resistance towards anthelmintic drugs has necessitated the search for alternative treatments for the control of gastrointestinal nematode parasites. Animals fed on chicory (Cichorium intybus L.), a temperate (pasture) crop, have reduced parasite burdens, hence making C. intybus a potentially useful source for novel anthelmintic compounds or a diet-based preventive/therapeutic option. Here, we utilized in vitro bioassays with the parasitic nematode Ascaris suum and molecular networking techniques with five chicory cultivars to identify putative active compounds. Network analysis predicted sesquiterpene lactones (SL) as the most likely group of anthelmintic compounds. Further bioassay-guided fractionation supported these predictions, and isolation of pure compounds demonstrated that the SL 8-deoxylactucin (8-DOL) is the compound most strongly associated with anti-parasitic activity. Furthermore, we showed that 8-DOL acts in a synergistic combination with other SL to exert the anti-parasitic effects. Finally, we established that chicory-derived extracts also showed activity against two ruminant nematodes (Teladorsagia circumcincta and Cooperia oncophora) in in vitro assays. Collectively, our results confirm the anti-parasitic activity of chicory against a range of nematodes, and pave the way for targeted extraction of active compounds or selective breeding of specific cultivars to optimize its future use in human and veterinary medicineSIWe are very grateful for the guidance and support by Dr. Thomas Ostenfeld Larsen and Christopher Phippen, Technical University of Denmark, Natural product discovery, and the laboratory assistance of Mette Schjelde, University of Copenhagen. This work was funded by the Danish Council for Independent Research (Grant DFF–6111-00394). Fractionation and purification of compounds were further supported by the Green Development and Demonstration Program (GUDP) (Project No. 34009-17-1220). MPE was supported by CONICYT Chile (FONDECYT Postdoctorado #3170875