Formulating Parasiticidal Fungi in Dried Edible Gelatins to Reduce the Risk of Infection by Trichuris sp. among Continuous Grazing Bison.

Control of infection by gastrointestinal nematodes remains a big problem in ruminants under continuous grazing. For the purpose of decreasing the risk of infection by Trichuris sp. in captive bison (Bison bison) always maintained in the same plot, dried gelatins having ≥106 chlamydospores of both Mucor circinelloides and Duddingtonia flagrans were given to them for one week, and at the end, fecal samples (FF) collected each week for four weeks were analyzed immediately. Feces taken one week prior to gelatin administration served as controls (CF). Eggs of Trichuris sp. were sorted into non-viable and viable, then classified into viable undeveloped (VU), viable with cellular development (VCD), or viable infective (VI). Ovistatic and ovicidal effects were determined throughout the study. In FF, viability of Trichuris eggs decreased between 9% (first week) and 57% (fourth week), egg development was delayed during the first two weeks, and VI percentages were significantly lower than in CF (p = 0.001). It is concluded that the preparation of gelatins with chlamydospores of parasiticidal fungi and their subsequent dehydration offer an edible formulation that is ready to use, stress-free to supply, and easy to store, as well as being well-accepted by ruminants and highly efficient to reduce the risk of Trichuris sp. infection among animals under continuous grazing regimes.

Acaricidal and Repellent Effects of Essential Oils against Ticks: A Review.

Tick control is a priority in order to prevent the transmission of vector-borne diseases. Industrial chemical acaricides and repellents have been the most efficient tools against hard ticks for a long time. However, the appearance of resistances has meant the declining effectiveness of the chemicals available on the market. The trend today is to develop alternative control methods using natural products to replace nonefficient pesticides and to preserve the efficient ones, hoping to delay resistance development. Traditional in vitro evaluation of acaricidal activity or resistance to synthetic pesticides have been reviewed and they mainly focus on just one species, the one host tick (Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)). Recent reports have called for the standardization of natural product components, extraction techniques, and experimental design to fully discover their acaricidal potential. This study reviews the main variables used in the bibliography about the efficiency of natural products against ticks, and it proposes a unification of variables relating to ticks, practical development of bioassays, and estimation of ixodicidal activity.

Control of Strongyles in First-Season Grazing Ewe Lambs by Integrating Deworming and Thrice-Weekly Administration of Parasiticidal Fungal Spores.

Parasiticidal fungi have been used in several in vivo experiments in livestock farms worldwide, constituting an effective tool for the biocontrol of gastrointestinal parasites in grazing animals. In the first year of study, two groups of eight first-season pasturing ewe lambs infected by strongyles were dewormed with albendazole, and then, the test group received an oral dose of 106 chlamydospores of Mucor circinelloides and 106 Duddingtonia flagrans individually and thrice a week from mid-September to May (FS1), while the control group remained without fungi (CT1). In the second year, two new groups of first-season grazing ewe lambs were treated with ivermectin and subjected to the same experimental design (FS2 and CT2, respectively). The anthelmintic efficacy was 96.6% (CT1), 95.6% (FS1), 96.1% (CT2), and 95.1% (FS2). The counts of strongyle egg output increased in the control groups (CT1 and CT2) throughout the study and reached numbers higher than 600 eggs per gram of feces (EPG), while in FS1 and FS2, they were <250 EPG. The values of red blood cell parameters registered for CT1 and CT2 were lower than those of the reference standards, while a significant increment was recorded in FS1 and FS2, and values within the physiological range were attained. It is concluded that integrating efficient anthelminthic deworming with rotational pasturing and the regular intake of chlamydospores of M. circinelloides and D. flagrans provides a helpful strategy for maintaining low levels of strongyle egg output in first-season grazing ewe lambs and improves their health status.

Analysis of the effect of COVID-19 on air pollution: perspective of the Spanish case.

The pandemic caused by coronavirus COVID-19 is having a worldwide impact that affects health and the economy and indirectly affects air pollution in cities. In Spain, the effect has evolved from being anecdotal in January 2020 to become the second country in Europe with the highest number of cases (614,000 cases by 17/09/2020), which has affected the health system and caused major mobility restrictions. In contrast, COVID-19 has affected air pollution and energy consumption in the country. This article analyzes the indirect effect produced by this pandemic on air pollution, referenced to various stages that occurred in Spain: first stage, without public awareness of COVID-19 impact (mid-January 2020); second is when Spanish Government alerted (late February 2020); and third, after the decree of alarm and mobility restriction of citizens by the government (March 2020) along with the various phases of the de-escalation. The indirect effect produced by this pandemic on air pollution in Spanish cities has been resulted in a decrement of 70% to 80% of average, taking into account dates after the decree of alarm and mobility restriction by the Spanish government (14/03/2020), compared to days prior to that date. Thus, the results of this analysis indicate a significant alteration in air pollutants; these alteration patterns have followed similar paths over different countries worldwide improving the air quality as discussed by Dutheil et al. (Environ Pollut (Barking, Essex: 1987) 263:114466, 2020).

Integrating the control of helminths in dairy cattle: Deworming, rotational grazing and nutritional pellets with parasiticide fungi.

Thirty-two Friesian cattle under a leaders/followers four-day rotation and passing eggs of trematodes and gastrointestinal nematodes (GIN) were studied in two trials for the integrated control of these helminths over two years. In the first trial, the effect of rotational pasturing was assessed on a group of leaders (milking cows, G-L1) and followers (dried-off cows and heifers, G-F1) supplemented daily with commercial nutritional pellets. In the second trial, leaders (G-L2) and followers (G-F2) were maintained under a rotational pasturing regime; the cows received daily commercial pelleted feed and heifers pellets manufactured with a blend of parasiticide fungi (3 × 105 chlamydospores of both Mucor circinelloides and Duddingtonia flagrans/kg pellet). Deworming via closantel and albendazole was performed in cows in each trial at the beginning of their drying periods, and fourteen days later, the fecal egg-count reductions (FECR) of Calicophoron daubneyi and GIN were from 94 to 100% (average 98 %), while the percentages of reduction of cattle shedding eggs (CPCR) were from 50 to 100% (average 77 % and 82 %, respectively). The heifers were dewormed one time only, at the beginning of each trial, and the values of FECR and CPCR were 100 % against C. daubneyi and 96 % and 83 %, respectively, against GIN. Over a period of 24 months, significantly higher numbers of helminth egg-output were observed in G-L1, with the lowest numbers in G-F2. C. daubneyi egg output was reduced by 5 % (G-L1) and 42 % (G-F1) at the end of trial 1 and by 83 % (G-L2) and 100 % (G-F2) at the end of trial 2; the numbers of GIN egg-output decreased by 13 % (G-L1) and 18 % (G-F1) at the end of trial 1, and by 72 % (G-L2) and 85 % (G-F2) at the end of trial 2. No adverse effects were detected in cattle taking pellets enriched with fungal spores (G-F2). It is concluded that long-term ingestion of spores of M. circinelloides and D. flagrans provides a valuable tool to improve the effect of rotational grazing and to lessen the risk of infection by C. daubneyi and GIN in dairy cattle, and accordingly, the performance of integrated control programs.

The egg hatch test: A useful tool for albendazole resistance diagnosis in Fasciola hepatica.

In the current study, the egg hatch test (EHT) has been evaluated as an in vitro technique to detect albendazole (ABZ) resistance in Fasciola hepatica. The intra- and inter-assay variations of the EHT were measured by means of the coefficient of variation in different fluke isolates and over time; then, the results of the EHT were compared with the "gold standard" controlled efficacy test, which assesses the in vivo anthelmintic efficacy. The EHT was used later to evaluate the intra-herd variability regarding the level of ABZ resistance in calves infected by the same fluke isolate. Finally, several factors of the initial protocol were modified to improve the simplicity of the assay, including the incubation time of eggs with the drug and the use of eggs collected from faeces. The greatest uniformity between results within the assay and over time until 8 weeks after gallbladder collection (the deadline proposed for egg analysis) was obtained with an ABZ concentration of 0.5 µM. The length of exposure to ABZ was shown to be critical, as prolonged incubation (15 days) led to a change of ovicidal activity. The ABZ concentration of 0.5 µM is suggested as a possible discriminating dose to predict ABZ resistance, due to the close agreement between the results of the EHT at an ABZ concentration of 0.5 µM and those of the in vivo assays.

In vitro anthelmintic activity and safety of different plant species against the ovine gastrointestinal nematode Teladorsagia circumcincta.

The present study was conducted to evaluate the in vitro anthelmintic activity and safety of methanolic and aqueous extracts of 9 plants against the ovine GIN Teladorsagia circumcincta. Initially the ovicidal efficacy of all extracts was tested at 50 mg/ml and at 1%, this last concentration for the methanolic extract of Elettaria cardamomum, by the Egg Hatch Assay. In those extracts with efficacy higher than 95%, the effective concentration required to inhibit 50% of egg hatching (EC50) and their cytotoxicity, as the lethal dose 50 (LC50), was also measured. The aqueous extracts of Aesculus hippocastanum, Isatis tinctoria, Chelidonium majus, E. cardamomum and Sisymbrium irio, with EC50 values ranging 1.30-2.88 mg/ml, and the aqueous extract of Jasminum polyanthum with a value of 6.41 mg/ml, showed the highest activities. The aqueous extract of J. polyanthum was the safest extract, followed by methanolic extract of E. cardamomum and aqueous extract of S. irio, all of them with a Selective Index higher than 1. According to our results, there is no correlation between the amount of total phenols or total tannins with the anthelmintic activity of the plants tested. Although results need to be interpreted with caution, as in vitro activity may not automatically translate into in vivo efficacy, those extracts with SI equal or higher than 1 and EC50 equal or lower than 6 mg/ml, could be taken into account for being used subsequently as feed or food additives in infected sheep.

Potential Usefulness of Filamentous Fungi to Prevent Zoonotic Soil-Transmitted Helminths.

The usefulness of a strategy involving the biological control of soil-transmitted helminths (STHs) with zoonotic potential is tested. A blend of spores of two filamentous fungi, Mucor circinelloides and Duddingtonia flagrans, was provided to one group (G-2) of puppies (five Griffon bleu de Gascogne and five Gascon Saintongeois) shedding eggs of Toxocara canis, Toxascaris leonina, Trichuris vulpis, and Ancylostoma caninum. Other identical group (G-1) remained without spores. Fecal samples were collected daily and divided into two portions, one sample was immediately analyzed by the flotation test and the other was examined 28 days later. Viability of eggs of T. canis, T. leonina, and T. vulpis in fecal pats was ascertained by microscopic examination; the numbers of larvae of A. caninum were assessed in each group. In the feces of G-2, spores of both fungi were observed 1 day after beginning the assay. Viability of eggs of T. canis was reduced by 57%, T. leonina by 61% and T. vulpis by 53% in the fecal pats of G-2, and by 87%, 92%, and 85%, respectively, in G-1. The numbers of third-stage larvae of A. caninum were 59% lower in G-2 than that in G-1. By considering the results obtained and the absence of adverse effects in the puppies of G-2, it is concluded that the presence of the filamentous fungi in the feces has a high potential to avoid the transmission of these parasites. Further studies are in progress to determine the appropriate way of administration to pets.

A combined effort to avoid strongyle infection in horses in an oceanic climate region: rotational grazing and parasiticidal fungi.

BACKGROUND: An approach to preventing strongyle infection in horses was tested, comprising rotational pasturing and the administration of spores of two parasiticidal fungi, Mucor circinelloides and Duddingtonia flagrans. METHODS: Twenty-two adult Spanish Sport Horses were dewormed with ivermectin (1 mg pour-on/kg body weight) and then randomly divided into three groups. G-1 was maintained with continuous grazing, and G-2 and G-3 were kept on a four-paddock rotation system. Commercial pelleted feed (2.5 kg/horse) was supplied to G-1 and G-2 twice a week; horses in G-3 received pellets containing 2 × 106 spores/kg of each fungus. Fecal samples were analyzed by the flotation method to estimate the reduction in the fecal egg counts (FECR), the percentage of horses shedding eggs (PHR), and the egg reappearance period (ERP). RESULTS: Third-stage larvae were identified in fecal pats as Cyathostomum (sensu lato) types A, C and D, Gyalocephalus capitatus, Triodontophorus serratus, Poteriosthomum spp., Strongylus vulgaris and S. edentatus. Two weeks after treatment, the FECR values were 100% in G-1, 96% in G-2 and 99% in G-3; the PHR values were 100% in G-1, 75% in G-2 and 88% in G-3. A strongyle ERP of 6 weeks was observed in G-1, ERP of 10 weeks was observed in G-2, and ERP of 16 weeks was observed in G-3. The counts of eggs per gram of feces (EPG) were > 300 EPG in G-1 and G-2 but remained below 250 EPG in G-3 throughout the observation period of 12 months. CONCLUSIONS: These results suggest that horse strongyle infection could be decreased by combining rotational pasturing with feeding pellets containing the spores of parasiticidal fungi.

DNA multigene characterization of Fasciola hepatica and Lymnaea neotropica and its fascioliasis transmission capacity in Uruguay, with historical correlation, human report review and infection risk analysis.

BACKGROUND: Fascioliasis is a pathogenic disease transmitted by lymnaeid snails and recently emerging in humans, in part due to effects of climate changes, anthropogenic environment modifications, import/export and movements of livestock. South America is the continent presenting more human fascioliasis hyperendemic areas and the highest prevalences and intensities known. These scenarios appear mainly linked to altitude areas in Andean countries, whereas lowland areas of non-Andean countries, such as Uruguay, only show sporadic human cases or outbreaks. A study including DNA marker sequencing of fasciolids and lymnaeids, an experimental study of the life cycle in Uruguay, and a review of human fascioliasis in Uruguay, are performed. METHODOLOGY/PRINCIPAL FINDINGS: The characterization of Fasciola hepatica from cattle and horses of Uruguay included the complete sequences of the ribosomal DNA ITS-2 and ITS-1 and mitochondrial DNA cox1 and nad1. ITS-2, ITS-1, partial cox1 and rDNA 16S gene of mtDNA were used for lymnaeids. Results indicated that vectors belong to Lymnaea neotropica instead of to Lymnaea viator, as always reported from Uruguay. The life cycle and transmission features of F. hepatica by L. neotropica of Uruguay were studied under standardized experimental conditions to enable a comparison with the transmission capacity of F. hepatica by Galba truncatula at very high altitude in Bolivia. On this baseline, we reviewed the 95 human fascioliasis cases reported in Uruguay and analyzed the risk of human infection in front of future climate change estimations. CONCLUSIONS/SIGNIFICANCE: The correlation of fasciolid and lymnaeid haplotypes with historical data on the introduction and spread of livestock into Uruguay allowed to understand the molecular diversity detected. Although Uruguayan L. neotropica is a highly efficient vector, its transmission capacity is markedly lower than that of Bolivian G. truncatula. This allows to understand the transmission and epidemiological differences between Andean highlands and non-Andean lowlands in South America. Despite rainfall increase predictions for Uruguay, nothing suggests a trend towards a worrying human infection scenario as in Andean areas.

Effect of the Filamentous Fungus Mucor circinelloides On The Development of Eggs of the Rumen Fluke Calicophoron daubneyi (Paramphistomidae).

Ruminants infected by Paramphistomidae flukes shed eggs in the feces, which pass through different stages in the environment until the infective stages (metacercariae) are reached. The activity of the soil fungus Mucor circinelloides on the development of eggs of the rumen fluke Calicophoron daubneyi was presently tested with 3 probes, i.e., in petri plates, feces, and an aqueous environment (tubes). The effect of the fungus was assessed by recording the numbers of undeveloped, nonviable, and embryonated eggs. Nonviable eggs were considered when vacuolization occurred, the inner structures were not clearly observed, the eggshell was broken, or the embryo inside was destroyed. By considering the ability of hyphae of M. circinelloides to develop in the presence of C. daubneyi eggs, attach to their surface, and penetrate and destroy the inner embryo, this ovicidal effect was classified as type 3. After a period of 50 days, the percentage of undeveloped eggs in the feces of infected cattle was 40%; furthermore, 27% of the eggs were nonviable, and 33% were embryonated (1 miracidium inside). The addition of 4 doses of M. circinelloides spores directly onto the feces resulted in 9-31% undeveloped eggs, 38-60% nonviable eggs, and 9-21% embryonated eggs, and no statistical significances were obtained among the different doses. Placing the eggs of C. daubneyi into an aqueous solution containing 107 spores of M. circinelloides/ml for 29 days resulted in 43% undeveloped eggs, 40% nonviable eggs, and 17% embryonated eggs, whereas in the controls, the percentages were 48%, 12%, and 40%, respectively. These data demonstrate the usefulness of the spores of the fungus M. circinelloides in limiting the development of the eggs of the trematode C. daubneyi.