Effects of artemisinin and Artemisia extracts on Haemonchus contortus in gerbils (Meriones unguiculatus)

Anthelmintic efficacy of an organic fraction from Guazuma ulmifolia leaves and evaluation of reactive oxidative stress on Haemonchus contortus

This study describes the anthelmintic efficacy of an organic fraction (EtOAc-F) from Guazuma ulmifolia leaves and the evaluation of its reactive oxidative stress on Haemonchus contortus. The first step was to assess the anthelmintic effect of EtOAc-F at 0.0, 3.5, 7.0 and 14 mg kg of body weight (BW) in gerbil's (Meriones unguiculatus) artificially infected with H. contortus infective larvae (L3). The second step was to evaluate the preliminary toxicity after oral administration of the EtOAc-F in gerbils. Finally, the third step was to determine the relative expression of biomarkers such as glutathione (GPx), catalase (CAT), and superoxide dismutase (SOD) against H. contortus L3 post-exposition to EtOAc-F. Additionally, the less-polar compounds of EtOAc-F were identified by gas mass spectrophotometry (GC-MS). The highest anthelmintic efficacy (97.34%) of the organic fraction was found in the gerbils treated with the 14 mg/kg of BW. Histopathological analysis did not reveal changes in tissues. The relative expression reflects overexpression of GPx (p<0.05, fold change: 14.35) and over expression of SOD (p≤0.05, fold change: 0.18) in H. contortus L3 exposed to 97.44 mg/mL of EtOAc-F compared with negative control. The GC-MS analysis revealed the presence of 4-hydroxybenzaldehyde (1), leucoanthocyanidin derivative (2), coniferyl alcohol (3), ferulic acid methyl ester acetate (4), 2,3,4-trimethoxycinnamic acid (5) and epiyangambin (6) as major compounds. According to these results, the EtOAc-F from G. ulmifolia leaves exhibit anthelmintic effect and increased the stress biomarkers on H. contortus.

Development and Evaluation of Self-Microemulsifying Drug Delivery System for Improving Oral Absorption of Poorly Water-Soluble Olaparib

The purpose of this study is to develop and evaluate a self-microemulsifying drug delivery system (SMEDDS) to improve the oral absorption of poorly water-soluble olaparib. Through the solubility test of olaparib in various oils, surfactants and co-surfactants, pharmaceutical excipients were selected. Self-emulsifying regions were identified by mixing the selected materials at various ratios, and a pseudoternary phase diagram was constructed by synthesizing these results. The various physicochemical properties of microemulsion incorporating olaparib were confirmed by investigating the morphology, particle size, zeta potential, drug content and stability. In addition, the improved dissolution and absorption of olaparib were also confirmed through a dissolution test and a pharmacokinetic study. An optimal microemulsion was generated in the formulation of Capmul^® MCM 10%, Labrasol^® 80% and PEG 400 10%. The fabricated microemulsions were well-dispersed in aqueous solutions, and it was also confirmed that they were maintained well without any problems of physical or chemical stability. The dissolution profiles of olaparib were significantly improved compared to the value of powder. Associated with the high dissolutions of olaparib, the pharmacokinetic parameters were also greatly improved. Taken together with the results mentioned above, the microemulsion could be an effective tool as a formulation for olaparib and other similar drugs.

Essential oils and essential oil compounds in animal production as antimicrobials and anthelmintics: an updated review

Several countries have shown an increased prevalence of drug resistance in animal production due to the indiscriminate use of antibiotics and antiparasitics in human and veterinary medicine. This article aims to review existing methods using naturally occurring essential oils (EOs) and their isolated compounds (EOCs) as alternatives to antimicrobials and antiparasitic compounds in animal production and, consequently, to avoid resistance. The most-reported mechanism of action of EOs and EOCs was cell membrane damage, which leads to the leakage of cytoplasmic content, increased membrane permeability, inhibition of metabolic and genetic pathways, morphologic changes, antibiofilm effects, and damage to the genetic material of infections. In parasites, anticoccidial effects, reduced motility, growth inhibition, and morphologic changes have been reported. Although these compounds regularly show a similar effect to those promoted by traditional drugs, the elucidation of their mechanisms of action is still scarce. The use of EOs and EOCs can also positively influence crucial parameters in animal production, such as body weight gain, feed conversion rate, and cholesterol reduction, which also positively impact meat quality. The application of EOs and EOCs is enhanced by their association with other natural compounds or even by the association with synthetic chemicals, which has been found to cause synergism in their antimicrobial effect. By reducing the effective therapeutical/prophylactic dose, the chances of off-flavors – the most common issue in EO and EOC application – is greatly mitigated. However, there is very little work on the combination of EOs and EOCs in large in vivo studies. In addition, research must apply the correct methodology to properly understand the observed effects; for example, the use of only high concentrations may mask potential results obtained at lower dosages. Such corrections will also allow the elucidation of finer mechanisms and promote better biotechnologic use of EOs and EOCs. This manuscript presents several information gaps to be filled before the use of EOs and EOCs are fully applicable in animal production.

Antiparasitic Tannin-Rich Plants from the South of Europe for Grazing Livestock: A Review

Internal parasites are one of the main causes of health threats in livestock production, especially in extensive livestock farming. Despite the environmental toxic effects (loss of dung beetles, biodiversity, and other issues) and resistance phenomenon derived from their prolonged use, anti-parasitic chemical pharmaceuticals are frequently used, even in organic farming. Such a situation within the context of climate change requires urgent exploration of alternative compounds to solve these problems and apparent conflicts between organic farming objectives regarding the environment, public health, and animal health. This review is focused on some plants (Artemisia spp., Cichorium intybus L., Ericaceae family, Hedysarum coronarium L., Lotus spp., Onobrychis viciifolia Scop.) that are well known for their antiparasitic effect, are voluntarily grazed and ingested, and can be spontaneously found or cultivated in southern Europe and other regions with a Mediterranean climate. The differences found between effectiveness, parasite species affected, in vitro/in vivo experiments, and active compounds are explored. A total of 87 papers where antiparasitic activity of those plants have been studied are included in this review; 75% studied the effect on ruminant parasites, where gastrointestinal nematodes were the parasite group most studied (70%), and these included natural (31%) and experimental (37%) infections.

In Vitro Nematocidal Effect and Anthelmintic Activity of Artemisia cina Against Haemonchus contortus in Gerbils and Relative Expression of Hc29 Gene in Transitional Larvae (L3-L4)

PURPOSE

(1) To assess the in vitro activity of Artemisia cina against Haemonchus contortus L₃ (HcL₃) and in transitional (L₃-L₄) larvae (HcTrL₃-L₄); (2) to quantify the relative expression of the Hc29 gene in HcTrL₃-L₄ exposed to the A. cina n-hexane extract; and (3) to assess the anthelmintic activity (AA) of the A. cina organic extracts in gerbils artificially infected with H. contortus (HcArt/inf/gerbs).

METHODS

The in vitro assay was carried out in 96-well microtitration plates. The following A. cina extracts: ethyl acetate (Ac-EtOAcEx), n-hexane (Ac-n-HexEx), and methanol (Ac-MethEx) were assessed at 1 and 2 mg/mL against HcL₃ and HcTrL₃-L₄ at 24 h exposure. Relative expression of the Hc29 gene in HcTrL₃-L₄ was obtained by RT-PCR. For assessing the AA, six groups of five HcArt/inf/gerbs were used. Groups were treated orally with 4 mg/kg BW of A. cina extracts. Five days after treatment, the gerbils were necropsied and nematodes counted.

RESULTS

The highest in vitro activities (75 and 82.6%) were shown by Ac-n-HexEx at 1 and 2 mg/mL, respectively. For HcTrL₃-L₄ the highest in vitro activities (69 and 23%) were shown by Ac-n-HexEx and isoguaiacine at 0.625 mg/mL, respectively. Also, upregulation of H. contortus Hc29 gene by 13- and 80-fold (p < 0.01) was observed on the HcTrL₃-L₄ stage after exposure to Ac-n-HexEx extract and isoguaiacine at 0.078 mg/mL, respectively. Reduction percentage was 100% in HcArt/inf/gerbs treated with Ac-n-HexEx.

CONCLUSIONS

We conclude that the Ac-n-HexEx and isoguaiacine compound had anthelmintic efficacy against H. contortus and L₃ and HcTrL₃-L₄.

Nematicidal activity of a hydroalcoholic extract of the edible mushroom Neolentinus ponderosus on L3 larvae of Haemonchus contortus

OBJECTIVE

In the present study, the in vitro and in vivo effect of the hydroalcoholic extract of Neolentinus ponderosus (EHNP) on L₃ larvae of Haemonchus contortus was evaluated.

MATERIAL AND METHODS

The N. ponderosus fungus was cultivated in potato dextrose liquid medium for 7 days at 120 rpm and 25 °C. Subsequently, the EHNP was obtained; in vitro bioassays were performed in 96-well plates. Furthermore, an in vitro confrontation with different concentrations of EHNP was carried out at 72 h against L3 larvae of H. contortus. The controls used were distilled water and ivermectin at 5 mg/mL. Subsequently, the in vivo activity of EHNP was evaluated using the gerbil against H. contortus L3 larvae as an experimental model. The experimental design consisted of four groups with: (1) distilled water, (2) fenbendazole at 20 mg/kg of body weight, (3) EHNP at a dose of 81 µg/mL, and (4) EHNP at a dose of 40 µg/mL.

RESULTS

In vitro study showed 97% mortality of the parasite H. contortus at a concentration of 3.4 mg/mL and a lethal concentration (LC90) of 2 mg/mL EHNP. In the in vivo assessment the highest mortality was (49%) at 72 h at a concentration of 81 µg/mL bw.

CONCLUSION

The result of the present study shows that EHNP has nematicidal activity in vitro and in vivo tests (close to 97% and 50%, respectively), the fungus N. ponderosus should be considered in future tests to elucidate the secondary metabolites through spectroscopic studies.

A Complementary Herbal Product for Controlling Giardiasis

Giardiasis is an intestinal protozoal disease caused by Giardia lamblia. The disease became a global health issue due to development of resistance to commonly used drugs. Since many plant-derived products have been used to treat many parasitic infestations, we aimed to assess the therapeutic utility of Artemisia annua (A. annua) for giardiasis. We showed that NO production was significantly reduced whereas serum levels of IL-6, IFN-γ, and TNF-α were elevated in infected hamsters compared to uninfected ones. Additionally, infection resulted in increased numbers of intraepithelial lymphocytes and reduced villi heights, goblet cell numbers, and muscularis externa thickness. We also showed that inducible NO synthase (iNOS) and caspase-3 were elevated in the intestine of infected animals. However, treatment with A. annua significantly reduced the intestinal trophozoite counts and IEL numbers, serum IL-6, IFN-γ, and TNF-α, while increasing NO and restoring villi heights, GC numbers, and ME thickness. Moreover, A. annua treatment resulted in lower levels of caspase-3, which indicates a protective effect from apoptotic cell death. Interestingly, A. annua therapeutic effects are comparable to metronidazole. In conclusion, our results show that A. annua extract is effective in alleviating infection-induced intestinal inflammation and pathological effects, which implies its potential therapeutic utility in controlling giardiasis.

In vitro assessment of the efficacy of protein exudates from seeds against Haemonchus contortus

Nematodes develop resistance to the most common commercially available drugs. The aim of this study was to identify and evaluate the action of protein exudates from Mimosa caesalpiniifolia, Leucaena leucocephala, Acacia mangium, and Stylosanthes capitata seeds on the gastrointestinal nematode Haemonchus contortus. The exuded proteins were precipitated, dialyzed, lyophilized, and assessed for their effect on egg hatching and artificial larval exsheathment inhibition. Proteome analysis of the protein extracts was also performed. Although no egg-hatching inhibition was observed, all exudates showed efficacy in inhibiting the larval exsheathment of H. contortus larvae with an EC₅₀ varying from 0.61 to 0.26 mg P mL^-1. Proteomic analysis revealed the presence of proteases, protease inhibitors, chitinases, and lectins among other proteins in the exudates. Most of the exuded proteins belong to the oxidative stress/plant defense and energy/carbohydrate metabolism functional clusters. This study concluded that the bioactive proteins from different classes exuded by seeds of M. caesalpiniifolia, L. leucocephala, A. mangium, and S. capitata show stage-specific inhibition against H. contortus.

Phytochemicals and Potential Therapeutic Targets on Toxoplasma gondii Parasite

Identification of drug target in protozoan T. gondii is an important step in the development of chemotherapeutic agents. Likewise, exploring phytochemical compounds effective against the parasite can lead to the development of new drug agent that can be useful for prophylaxis and treatment of toxoplasmosis. In this review, we searched for the relevant literature on the herbs that were tested against T. gondii either in vitro or in vivo, as well as different phytochemicals and their potential activities on T. gondii. Potential activities of major phytochemicals, such as alkaloid, flavonoid, terpenoids and tannins on various target sites on T. gondii as well as other related parasites was discussed. It is believed that the phytochemicals from natural sources are potential drug candidates for the treatment of toxoplasmosis with little or no toxicity to humans.

Artemisia absinthium L.-Importance in the History of Medicine, the Latest Advances in Phytochemistry and Therapeutical, Cosmetological and Culinary Uses

Artemisia absinthium-wormwood (Asteraceae)-is a very important species in the history of medicine, formerly described in medieval Europe as "the most important master against all exhaustions". It is a species known as a medicinal plant in Europe and also in West Asia and North America. The raw material obtained from this species is Absinthii herba and Artemisiae absinthii aetheroleum. The main substances responsible for the biological activity of the herb are: the essential oil, bitter sesquiterpenoid lactones, flavonoids, other bitterness-imparting compounds, azulenes, phenolic acids, tannins and lignans. In the official European medicine, the species is used in both allopathy and homeopathy. In the traditional Asian and European medicine, it has been used as an effective agent in gastrointestinal ailments and also in the treatment of helminthiasis, anaemia, insomnia, bladder diseases, difficult-to-heal wounds, and fever. Today, numerous other directions of biological activity of the components of this species have been demonstrated and confirmed by scientific research, such as antiprotozoal, antibacterial, antifungal, anti-ulcer, hepatoprotective, anti-inflammatory, immunomodulatory, cytotoxic, analgesic, neuroprotective, anti-depressant, procognitive, neurotrophic, and cell membrane stabilizing and antioxidant activities. A. absinthium is also making a successful career as a cosmetic plant. In addition, the importance of this species as a spice plant and valuable additive in the alcohol industry (famous absinthe and vermouth-type wines) has not decreased. The species has also become an object of biotechnological research.

Anthelmintic Activity of Yeast Particle-Encapsulated Terpenes

Soil-transmitted nematodes (STN) infect 1-2 billion of the poorest people worldwide. Only benzimidazoles are currently used in mass drug administration, with many instances of reduced activity. Terpenes are a class of compounds with anthelmintic activity. Thymol, a natural monoterpene phenol, was used to help eradicate hookworms in the U.S. South circa 1910. However, the use of terpenes as anthelmintics was discontinued because of adverse side effects associated with high doses and premature stomach absorption. Furthermore, the dose-response activity of specific terpenes against STNs has been understudied. Here we used hollow, porous yeast particles (YPs) to efficiently encapsulate (>95%) high levels of terpenes (52% w/w) and evaluated their anthelmintic activity on hookworms (Ancylostoma ceylanicum), a rodent parasite (Nippostrongylus brasiliensis), and whipworm (Trichuris muris). We identified YP-terpenes that were effective against all three parasites. Further, YP-terpenes overcame albendazole-resistant Caenorhabditis elegans. These results demonstrate that terpenes are broad-acting anthelmintics. Terpenes are predicted to be extremely difficult for parasites to resist, and YP encapsulation provides water-suspendable terpene materials without surfactants and sustained terpene release that could lead to the development of formulations for oral delivery that overcome fast absorption in the stomach, thus reducing dosage and toxic side effects.

Combined Use of Indirect ELISA and Western Blotting with Recombinant Hepatocellular Carcinoma-Associated Antigen 59 Is a Potential Immunodiagnostic Tool for the Detection of Prepatent Haemonchus contortus Infection in Goat

Simple Summary

The accurate and early diagnosis of Haemonchus contortus infection is crucial for effective control. Early stage detection of H. contortus infection has not been attempted in goat, even though both immature worm and fourth larval stage are blood sucking. This study was carried out to detect the H. contortus infection during early stage in goat. The results of this study assessed that rHc-HCA59 could detect the antibody in H. contortus infected goats’ sera during early period with good sensitivity and specificity using immunodiagnostic techniques. Our findings illustrated that combined use of ELISA and western blotting based on rHc-HCA59 is a powerful tool for early detection of H. contortus infection in goats.

Abstract

Haemonchus contortus is recognized as one of the important health problems in small ruminants, leading to reduced production and economic loss for farmers worldwide. Prepatent diagnosis of H. contortus infection is crucial to improve control strategies as this helminth may remove up to one-fifth of total erythrocytes and may cause anemia, edema, diarrhea, and ultimately death in young animals. In this study, one of the excretory and secretory products, rHc-HCA59, was purified and used as antigen to detect specific antibodies in H. contortus infected goats during prepatent stage of infection using indirect enzyme linked immunosorbent assay (ELISA) as screening test. All goats (n = 38) were housed indoor, experimentally infected with 8000 infective larvae (L3) of H. contortus, and serum samples were collected prior to infection and at 14th day of infection. Immunoblotting was performed to confirm the results of indirect ELISA, evaluate the cross reactivity against rHc-HCA59 in sera of most common co-infecting parasites and rectify the false negative samples. Furthermore, three different batches of rHc-HCA59 were produced to evaluate the repeatability of ELISA. No eggs were detected in feces of all goats collected at 7th and 14th day of infection but, H. contortus eggs were detected at 21 days post infection in the feces. Indirect ELISA performed in this study showed 87% sensitivity and 100% specificity. The western blot analysis confirmed immunoreactivity in serum samples which scored positive in indirect ELISA and recognized the samples as negative which had OD₄₅₀ lower than negative cut-off value in indirect ELISA. Furthermore, all false negative sera (n = 5) that had OD₄₅₀ value between positive and negative cut-off value in rHc-HCA59 based ELISA were clearly positive in western blot. Moreover, no cross-reactivity was detected in ELISA and western blotting against rHc-HCA59 in positive sera of Toxoplasma gondii, Fasciola hepatica, and Trichinella spiralis. The results of this study concluded that combined use of indirect ELISA and western blotting with rHc-HCA59 is a potential immunodiagnostic tool for the detection of H. contortus infection during prepatent period in goats.

Chemical Profile and Biological Activities of Essential Oil from Artemisia vulgaris L. Cultivated in Brazil

Essential oil from the leaves of Artemisia vulgaris L. (Compositae) cultivated in Brazil was investigated for its chemical composition and biological activities including antibacterial, antifungal, and anthelmintic. The constituents of essential oils isolated by hydro-distillation were examined by GC-MS and a total of 18 components were identified. The essential oil was dominated by oxygenated sesquiterpenes (44.4%), sesquiterpene hydrocarbons (33.3%), and oxygenated monoterpenes (16.6%). Caryophyllene (37.45%), germacrene D (16.17%), and humulene (13.66%) were the major components. The essential oils from A. vulgaris showed bactericidal and fungicidal properties against Staphylococcus aureus and Candida albicans, respectively. Anthelmintic activity against Haemonchus contortus was absent in this essential oil. Altogether above results indicate that essential oils from A. vulgaris can be used for various medicinal purposes.

A survey of Haemonchus contortus parasite of sheep from Gharb plain, Morocco

The study was designed to determine the prevalence of Haemonchus contortus, intestinal helminthes parasite of sheep in the Gharb plain (Morocco).

A total of 1154 sheep were randomly selected from farms, pastures and abattoirs, the samples were examined using a flotation techniques for determination the eggs of Haemonchus contortus. In order to identify Haemonchus contortus among the different gastrointestinal strongyles present in mixed infections, a faecal culture was carried out for each farm and pasture. This study was carried between November 2016 and October 2017. The data were analysed with respect to sex, age, season and body condition of sheep examined. Out of (1154) samples examined, (23.92%) harbored H. contortus. Prevalence among female (30.98%) was higher than that of the males (15.63%), there was significant difference between prevalence of infection and sex (P < 0.05). Based on age group, prevalence of haemonchosis was 6.25% and 43.22% in young and aged animals respectively showing the statistical significance (P < 0.05). Seasonal variation was recorded throughout the year and was highest during spring (36.36%) and autumn (32.37%) against a low rate of 2.7% in the summer with significance difference (P < 0.05). Regarding the relationship between Haemonchosis contortus and body condition, maximum prevalence (80.83%) was recorded in animals with poor body condition, followed by those with moderate body condition (34.26%), while the lowest infestation rate (6.88%) is noted in animals with good body.

A cysteine protease from the latex of Ficus benjamina has in vitro anthelmintic activity against Haemonchus contortus

Abstract Haemonchus contortus is a gastrointestinal nematode that is responsible for high mortality rates in ruminant herds. The resistance of nematodes to synthetic anthelmintics is widespread and requires a continuous search for new bioactive molecules, such as proteins. The objective of this study was to evaluate the anthelmintic potential of a protease purified from the latex of Ficus benjamina against H. contortus . Fresh latex was collected from plants via small incisions in the green stems, the rubber was removed by centrifugation, and the latex protein extract (LPE) was obtained. After LPE fractionation with ammonium sulfate and chromatography of the fraction containing the highest proteolytic activity on CM-cellulose, a cysteine protease (FbP) was purified. FbP has a molecular mass of approximately 23.97 kDa, and its proteolytic activity was stable between pH 6.0 and pH 10 and over a broad temperature range, with optimum activity at 60 °C. FbP inhibited both the development and exsheathment of H. contortus larvae, with 50% effective concentrations of 0.26 and 0.79 mg/mL, respectively. We conclude that this cysteine protease from F. benjamina latex with anthelmintic activity against H. contortus could be a promising alternative for the development of products for use in parasite control programmes.

Efficacy of essential oils from plants cultivated in the Amazonian Biome against gastrointestinal nematodes in sheep

The excessive use of anthelmintics to control nematodes has resulted in anthelminthic resistance. Essential oils (EOs) are a rich source of bioactive molecules that can be assessed for their ability to control resistant parasite populations. The aims of this study were to screen EOs from 10 plant species in vitro for anthelmintic activity against Haemonchus contortus, evaluate the cytotoxicity of those EOs in a human immortalized keratinocyte cell line (HaCaT), and test the most promising EO candidate in vivo in Santa Inês sheep. The efficacy was investigated in vitro using an egg hatch test (EHT) and a larval development test (LDT). EO cytotoxicity was evaluated with the sulforhodamine-B assay. In the in vivo experiment, 28 Santa Inês sheep naturally infected were distributed into groups: G1-Mentha arvensis (EO5), 200 mg kg-1; G2-menthol, 160 mg kg-1; G3-negative control; and G4-positive control (monepantel). EO5, from M. arvensis (86.7% menthol), had the lowest LC50 and LC90 values in the EHT (0.10, 0.27 mg mL-1, respectively), good performance in the LDT (0.015, 0.072 mg mL-1, respectively), and the lowest cytotoxicity (190.9 µg mL-1) in HaCaT cells. In the in vivo test, a single dose of the EO5 (200 mg kg-1 BW) had an efficacy of approximately 50% on days 1, 14, and 21; however, values were not significantly from day 0. Conversely, pure menthol at a dose of 160 mg kg-1 BW showed no in vivo efficacy. This can be attributed to key factors related to bioavailability and pharmacology of terpenes in the host organism, as well as to the fact that menthol is mainly excreted as glucuronides in urine. Thus, further studies should be conducted with formulation systems that deliver bioactives directly to the abomasum, focusing on terpenes, whose excretion route is mainly via faeces.

Limitations in the screening of potentially anti-cryptosporidial agents using laboratory rodents with gastric cryptosporidiosis

The emergence of cryptosporidiosis, a zoonotic disease of the gastrointestinal and respiratory tract caused by Cryptosporidium Tyzzer, 1907, triggered numerous screening studies of various compounds for potential anti-cryptosporidial activity, the majority of which proved ineffective. Extracts of Indonesian plants, Piper betle and Diospyros sumatrana, were tested for potential anti-cryptosporidial activity using Mastomys coucha (Smith), experimentally inoculated with Cryptosporidium proliferans Kváč, Havrdová, Hlásková, Daňková, Kanděra, Ježková, Vítovec, Sak, Ortega, Xiao, Modrý, Chelladurai, Prantlová et McEvoy, 2016. None of the plant extracts tested showed significant activity against cryptosporidia; however, the results indicate that the following issues should be addressed in similar experimental studies. The monitoring of oocyst shedding during the entire experimental trial, supplemented with histological examination of affected gastric tissue at the time of treatment termination, revealed that similar studies are generally unreliable if evaluations of drug efficacy are based exclusively on oocyst shedding. Moreover, the reduction of oocyst shedding did not guarantee the eradication of cryptosporidia in treated individuals. For treatment trials performed on experimentally inoculated laboratory rodents, only animals in the advanced phase of cryptosporidiosis should be used for the correct interpretation of pathological alterations observed in affected tissue. All the solvents used (methanol, methanol-tetrahydrofuran and dimethylsulfoxid) were shown to be suitable for these studies, i.e. they did not exhibit negative effects on the subjects. The halofuginone lactate, routinely administered in intestinal cryptosporidiosis in calves, was shown to be ineffective against gastric cryptosporidiosis in mice caused by C. proliferans. In contrast, the control application of extract Arabidopsis thaliana, from which we had expected a neutral effect, turned out to have some positive impact on affected gastric tissue.

Meriones unguiculatus infected by Haemonchus contortus: evaluation of different experimental protocols

Many important studies on resistance reversion, anthelmintic efficacy and, especially, new molecules with antiparasitic effects are performed in laboratories using gerbils (Meriones unguiculatus) as the experimental model. This study aimed to evaluate the use of corticosteroids (dexamethasone and methylprednisolone acetate) in gerbils experimentally infected with different doses of infective larvae (sheathed or exsheathed) of Haemonchus contortus. In the first experiment, 28 gerbils were divided into seven groups infected by 2-6 × 103 larvae, with or without immunosuppression using corticosteroids. In the second experiment, eight gerbils were divided into two groups infected by 2 × 103 sheathed or exsheathed larvae. For the third assay, seven immunosuppressed gerbils were infected with 2 × 103 sheathed larvae and were killed 15 days post infection (PI). The highest number of parasites was recovered from methylprednisolone-immunosuppressed animals. We observed red and white blood cell alterations and biochemical parameters in infected animals that had undergone immunosuppression with methylprednisolone. We highlight that in the first and second experiments a satisfactory number of worms was recovered using sheathed larvae and immunocompetent animals. When exsheathed larvae were used, the number of worms recovered was unsatisfactory. A considerable larval burden was recovered from immunosuppressed gerbils 15 days PI, and body weight did not influence establishment of larvae.

Characterization of the development of Haemonchus contortus ZJ strain from gerbils

BACKGROUND

Haemonchus contortus is a serious parasitic nematode in domestic ruminants around the world, including China. Haemonchus contortus has developed extensive resistance to commercial anthelmintics, which has produced a demand for new control methods, such as more effective drugs. Gerbils infected with H. contortus have previously been used as a model for anthelmintics selections, and the growth of H. contortus had been briefly examined. To enhance the model, this study provides an additional description of the development of H. contortus ZJ strain in gerbils.

RESULTS

Gerbils were infected with H. contortus ZJ strain at a dose of 2000 exsheathed infective larvae (xL3s) and sacrificed at 4, 7 and 18 days post-infection (dpi). Only fourth-stage larvae were found in the stomachs. About 2% of the inoculums were obtained at each of the three sampling time points. Larvae grew more slowly in gerbils than in sheep, but presented almost the same morphology. Rod-like crystalline inclusions were present in the intestinal cells of larvae, indicating that the metabolic rate of larvae was probably greatly reduced. Histological examination of stomach sections showed that larvae are located in the lumens or at the mucosal surfaces, with few inflammatory changes evident.

CONCLUSIONS

The development and features of H. contortus ZJ strain in gerbils were described. Our results provide supplementary information of H. contortus growth in gerbils, especially the presence of rod-like crystalline inclusions, and may contribute to improve the anthelmintic selection system.

Selective nematocidal effects of essential oils from two cultivated Artemisia absinthium populations

Essential oils (EOs) obtained from two crops and populations of thujone-free cultivated Artemisia absinthium were tested against two nematode models, the mammalian parasite Trichinella spiralis, and the plant parasitic root knot nematode Meloidogyne javanica. The EOs were characterized by the presence of (Z)-epoxyocimene and chrysanthenol as major components and showed time and population dependent quantitative and qualitative variations in composition. The EOs showed a strong ex vivo activity against the L1 larvae of the nematode Trichinella spiralis with a reduction of infectivity between 72 and 100% at a dose range of 0.5-1 mg/ml in absence of cytotoxicity against mammalian cells. Moreover, the in vivo activity of the EO against T. spiralis showed a 66% reduction of intestinal adults. However, these oils were not effective against M. javanica.

Anthelmintic activity of Cymbopogon citratus against Haemonchus contortus

Parasitic nematodes are of major economic importance in livestock. An alternative for the control of parasites is phytotherapy. This study evaluated the efficacy of Cymbopogon citratus decoction (CcD), C. citratus essential oil (CcEo) and citral against Haemonchus contortus using in vitro egg hatch test (EHT) and larval development test (LDT) and an in vivo test using a Meriones unguiculatus (gerbil) model. The effect of 800 mg/kg CcEo was evaluated in gerbils that had been artificially infected with 5,000 third-stage H. contortus larvae. The effective concentrations required to inhibit 50% (EC50) of egg hatching were 0.46, 0.14 and 0.13 mg/mL for CcD, CcEo and citral, respectively. The EC50 values in the LDT were 5.04, 1.92 and 1.37 mg/mL for CcD, CcEo and citral, respectively. H. contortus population in the group treated with C. citratus essential oil was reduced by 38.5% (P< 0.05) in comparison to the control group. These results suggest that it may be possible to use C. citratusessential oil to control of H. contortus parasite of small ruminant.

Effects of Artemisia annua and Foeniculum vulgare on chickens highly infected with Eimeria tenella (phylum Apicomplexa)

Background

Intensive poultry production systems depend on chemoprophylaxis with anticoccidial drugs to combat infection. A floor-pen study was conducted to evaluate the anticoccidial effect of Artemisia annua and Foeniculum vulgare on Eimeria tenella infection. Five experimental groups were established: negative control (untreated, unchallenged); positive control (untreated, challenged); a group medicated with 125 ppm lasalocid and challenged; a group medicated with A. annua leaf powder at 1.5% in feed and challenged; and a group treated with the mixed oils of A. annua and Foeniculum vulgare in equal parts, 7.5% in water and challenged. The effects of A. annua and oil extract of A. annua + F. vulgare on E. tenella infection were assessed by clinical signs, mortality, fecal oocyst output, faeces, lesion score, weight gain, and feed conversion.

Results

Clinical signs were noticed only in three chickens from the lasalocid group, six from the A. annua group, and nine from the A. annua + F. vulgare group, but were present in 19 infected chickens from the positive control group. Bloody diarrhea was registered in only two chickens from A. annua group, but in 17 chickens from the positive control group. Mortality also occurred in the positive control group (7/20). Chickens treated with A. annua had a significant reduction in faecal oocysts (95.6%; P = 0.027) and in lesion score (56.3%; P = 0.005) when compared to the positive control. At the end of experiment, chickens treated with A. annua leaf powder had the highest body weight gain (68.2 g/day), after the negative control group, and the best feed conversion (1.85) among all experimental groups.

Conclusions

Our results suggest that A. annua leaf powder (Aa-p), at 1.5% of the daily diet post-infection, can be a valuable alternative for synthetic coccidiostats, such as lasalocid.

Acaricidal activity of extract of Artemisia absinthium against Rhipicephalus sanguineus of dogs

The objective of the study was to evaluate the in vitro efficacy of different concentrations of chloroform extract obtained from the aerial parts of Artemisia absinthium in comparison to amitraz on adults, eggs and larvae of the dog tick Rhipicephalus sanguineus using the adult immersion test (AIT), egg hatchability test (EHT) and larval packet test (LPT), respectively. Five concentrations of the extract (1.25, 2.5, 5, 10 and 20 %) with three replications for each concentration were used in all the bioassays. A control group was established (water + dimethylsulphoxide) together with a positive control group (amitraz), with three repetitions each. In AIT, the mortality rates were 0.0, 13.3, 16.7, 33.3 and 93.3 % in concentrations of 1.25, 2.5, 5, 10 and 20 %, respectively, and the variation was significant (p=0.0151). The LC50 (CI) and LC95 (CI) values were calculated as 8.793 % (8.217-9.408) and 34.59 % (29.71-40.26), respectively. The egg production was reduced by 6.6, 6.6, 18.3, 42.5 and 85.1 % in the concentrations of 1.25, 2.5, 5, 10 and 20 %, respectively, and it was statistically significant (p=0.0274). In EHT, hatching was completely inhibited at 5, 10 and 20 % displaying 100 % ovicidal action while at the concentrations of 1.25 and 2.5 %, the inhibition rates were 20 and 60 %, respectively. In LPT, the extract caused 100 % mortality of larvae in the concentrations of 5, 10 and 20 % after 24 h while at the concentrations of 1.25 and 2.5 %, the mortality rates were 54.3 and 96.7 %, respectively. The LC50 (CI) and LC95 (CI) values were determined to be 1.11 % (1.099-1.121) and 2.37 % (2.328-2.423), respectively. The results show that the extract of A. absinthium has acaricidal properties and could be useful in controlling R. sanguineus which is an efficient vector of pathogens both in dogs and humans.

In vitro ovicidal and larvicidal activity of the essential oil of Artemisia lancea against Haemonchus contortus (Strongylida)

Prolonged use of chemical anthelmintics has been found to result in anthelmintic resistance and environmental issues, thereby limiting the application of these drugs in domestic animals and prompting interest in the study of plant extracts as alternative sources thereof. The aim of this study was to evaluate the in vitro effect of the essential oil (EO) of Artemisia lancea against the parasitic nematode Haemonchus contortus using egg hatch assay, larval development assay, and larval migration inhibition assay. The EO yield of extraction was 0.63% (w/w), and the major constituents were 1,8-cineole (34.56%) and camphor (16.65%). In the egg hatch assay, an inhibition greater than 99% was observed with the EO at 10 mg mL(-1) and the LC50 was 1.82 mg mL(-1). 1,8-Cineole demonstrated moderate ovicidal activity with a LC50 of 4.64 mg mL(-1), whereas camphor did not show enough activity to have its LC50 determined. In the larval development assay, the EO, 1,8-cineole, and camphor inhibited 93.6%, 65.2%, and 57% of larval development at 10 mg mL(-1) and exhibited dose-dependent responses with LC50 values of 1.66, 5.07, and 7.80 mg mL(-1), respectively. In the migration inhibition assay, the EO and 1,8-cineole at best inhibited 77% and 60.3% of larval migration at 10 mg mL(-1), respectively. Camphor showed low inhibition capacity, and its efficacy was not dose dependent. The results indicate that the in vitro anthelmintic activity of the EO of A. lancea may be associated with the additive action of the two major constituents, as well as other more minor terpenoid components.

Caenorhabditis elegans as a model to screen plant extracts and compounds as natural anthelmintics for veterinary use

The most challenging obstacles to testing products for their anthelmintic activity are: (1) establishing a suitable nematode in vitro assay that can evaluate potential product use against a parasitic nematode of interest and (2) preparation of extracts that can be redissolved in solvents that are miscible in the test medium and are at concentrations well tolerated by the nematode system used for screening. The use of parasitic nematodes as a screening system is hindered by the difficulty of keeping them alive for long periods outside their host and by the need to keep infected animals as sources of eggs or adults when needed. This method uses the free-living soil nematode Caenorhabditis elegans as a system to screen products for their potential anthelmintic effect against small ruminant gastrointestinal nematodes, including Haemonchus contortus. This modified method uses only liquid axenic medium, instead of agar plates inoculated with Escherichia coli, and two selective sieves to obtain adult nematodes. During screening, the use of either balanced salt solution (M-9) or distilled water resulted in averages of 99.7 (± 0.73)% and 96.36 (± 2.37)% motile adults, respectively. Adult worms tolerated DMSO, ethanol, methanol, and Tween 80 at 1% and 2%, while Labrasol (a bioenhancer with low toxicity to mammals) and Tween 20 were toxic to C. elegans at 1% and were avoided as solvents. The high availability, ease of culture, and rapid proliferation of C. elegans make it a useful screening system to test plant extracts and other phytochemical compounds to investigate their potential anthelmintic activity against parasitic nematodes.

In vitro trematocidal effects of crude alcoholic extracts of Artemisia annua, A. absinthium, Asimina triloba, and Fumaria officinalis: trematocidal plant alcoholic extracts

Trematode infections negatively affect human and livestock health, and threaten global food safety. The only approved human anthelmintics for trematodiasis are triclabendazole and praziquantel with no alternative drugs in sight. We tested six crude plant extracts against adult Schistosoma mansoni, Fasciola hepatica, and Echinostoma caproni in vitro. Mortality was best achieved by ethanolic extracts of Artemisia annua (sweet Annie), Asimina triloba (paw-paw), and Artemisia absinthium (wormwood) which, at 2 mg/mL, killed S. mansoni and E. caproni in 20 h or less (except for wormwood), F. hepatica between 16 and 23 h (sweet Annie), or 40 h (paw-paw). Some extracts were active at 0.2 mg/mL and 20 μg/mL, although more time was required to kill trematodes. However, aqueous A. annua and methanol extracts of Fumaria officinalis had no activity. Chromatographic analysis of the three best extracts established that A. annua and A. triloba extracts contained bioactive artemisinin and acetogenins (asimicin and bullatacin), respectively. The anthelmintic activity of our extracts at such low doses indicates that their anthelmintic activity deserves further testing as natural alternative controls for parasites of both animals and humans. Our results also support recent evidence that synergistic effects of multiple bioactive compounds present in crude plant extracts is worth exploring.