Plants as de-worming agents of livestock in the Nordic countries: historical perspective, popular beliefs and prospects for the future

Anthelmintic screening of Bangladeshi medicinal plants and related phytochemicals using in vitro and in silico methods: An ethnobotanical perspective

ETHNOPHARMACOLOGICAL RELEVANCE

Infections caused by parasitic worms or helminth continue to pose a great burden on human and animal health, particularly in underdeveloped tropical and subtropical countries where they are endemic. Current anthelmintic drugs present serious limitations and the emergence of drug resistance has made it increasingly challenging to combat such infections (helminthiases). In Bangladesh, medicinal plants are often used by indigenous communities for the treatment of helminthiases. Knowledge on such plants along with screening for their anthelmintic activity has the potential to lead to the discovery of phytochemicals that could serve as novel molecular scaffolds for the development of new anthelminthic drugs.

AIM OF THE STUDY

The purpose of this study was i) to conduct an ethnobotanical survey to gather data on Bangladeshi medicinal plants used in the treatment of helminthiases, ii) to test plants with the highest use values for their in vitro anthelmintic activity, and iii) to carry out in silico screening on phytochemicals present in the most active plant extract to investigate their ability to disrupt β-tubulin function in helminths.

METHODS

The ethnobotanical survey was conducted across three sub-districts of Bangladesh, namely Mathbaria, Phultala and Khan Jahan Ali. The in vitro screening for anthelmintic activity was performed in a motility test using adult Haemonchus contortus worms. Virtual screening using PyRx was performed on the phytochemicals reported from the most active plant, exploring their interactions with the colchicine binding site of the β-tubulin protein target (PDB ID: 1SA0).

RESULTS

The survey respondents reported a total of 32 plants for treating helminthiases. Based on their use values, the most popular choices were Ananas comosus (L.) Merr., Azadirachta indica A.Juss., Carica papaya L., Citrus maxima (Burm.) Merr., Curcuma longa L., Momordica charantia L., Nigella sativa L. and Syzygium cumini (L.) Skeels. In vitro anthelmintic testing revealed that A. indica leaves and bark had the highest activity with LC50 values of 16 mg/mL in both cases. Other plant extracts also exhibited good anthelmintic activity with LC50 values ranging from 16 to 52 mg/mL, while the value for albendazole (positive control) was 8.39 mg/mL. The limonoids nimbolide and 28-deoxonimbolide showed a binding affinity of -8.9 kcal/mol, and satisfied all drug-likeness parameters. The control ligand N-deacetyl-N-(2-mercaptoacetyl)colchicine had a binding affinity of -6.9 kcal/mol.

CONCLUSION

Further in silico and in vitro studies are warranted on the identified limonoids to confirm the potential of these derivatives as novel drug templates for helminthiases. The current study supports the need for an ethnobotanical survey-based approach to discover novel drug templates for helminthiases.

A Review of Ethnomedicinal Plants as Potential Anthelmintic Agents to Alternatively Control Gastrointestinal Nematodes of Ruminants in South Africa

Small ruminant production is one of the most important animal productions for food security in the world, especially in the developing world. Gastrointestinal nematode (GIN) infection is a threat to this animal's production. Conventional drugs that are used to control these parasites are losing their efficacy due to the development of resistant parasites. These drugs are not biologically degradable, taint meat products and are also expensive for communal farmers. Hence, research is now exploring ethnomedicinal anthelmintic plants for an alternative remedy. The objective of this paper was to review ethnomedicinal plants as a potential alternative to unsustainable commercial anthelmintics. This review sought to understand common GINs infecting ruminants, resistance manifestation in GINs to conventional treatment, reasons communal farmers choose ethnomedicine, and modes of action in anthelmintic plants. It also examined the usage of plants and plant parts, dosage forms, methods for improving bioactivity, convectional validation procedures, and restrictions on ethnomedicinal plant use as anthelmintics in ethnomedicine. Such insight is essential, as it highlights the importance of ethnoveterinary medicine and ways to adopt or improve it as a potential alternative to conventional anthelmintics.

Singab A. Botanicals against some important nematodal diseases: Ascariasis and hookworm infections

Ascariasis and intestinal parasitic nematodes are the leading cause of mass mortality infecting many people across the globe. In light of the various deleterious side effects of modern chemical-based allopathic drugs, our preferences have currently shifted towards the use of traditional plant-based drugs or botanicals for treating diseases. The defensive propensities in the botanicals against parasites have probably evolved during their co-habitation with parasites, humans and plants in nature and hence their combative interference in one another's defensive mechanisms has occurred naturally ultimately being very effective in treating diseases. This article broadly outlines the utility of plant-based compounds or botanicals prepared from various medicinal herbs that have the potential to be developed as effective therapies against the important parasites causing ascariasis and intestinal hookworm infections leading to ascariasis & infections and thereby human mortality, wherein allopathic treatments are less effective and causes enormous side-effects.

Anthelmintic Activity of Tanacetum vulgare L. (Leaf and Flower) Extracts against Trichostrongylidae Nematodes in Sheep In Vitro

Due to the high prevalence of gastrointestinal nematodes in sheep, the growing anthelmintic resistance, and the development of organic farming systems, sustainable alternatives are being sought. One such method is phytotherapy. This study aimed to evaluate the in vitro ovicidal and larvicidal activity of extracts of tansy (Tanacetum vulgare L.) growing in Latvia on gastrointestinal nematodes (Trichostrongylidae) in sheep. The leaves and flowers of the tansy were extracted separately in 70%, 50%, and 30% ethanol and acetone. Six concentrations were prepared from each extract 500 mg/mL, 200 mg/mL, 100 mg/mL, 50 mg/mL, 20 mg/mL, and 10 mg/mL. In vitro egg hatching test and micro-agar larval development test were performed. Extracts of tansy have strong larvicidal activity. The highest percentage of larvae inhibition for most of the extracts was 100%, but for egg inhibition, it was 95.8% for the 200 mg/mL concentration of 50% acetone and 93.3% for the 500 mg/mL concentration of 50% ethanol leaf extracts. All tansy extracts had ovicidal and larvicidal activity against Trichostrongylidae in sheep.

"Cow Healers Use It for Both Horses and Cattle": The Rise and Fall of the Ethnoveterinary Use of Peucedanum ostruthium (L.) Koch (fam. Apiaceae) in Sweden

Masterwort, Peucedanum ostruthium (L.) Koch, is an Apiaceae species originally native to the mountain areas of central and southern Europe. Written sources show that it was used in northern Europe. This study explores the cultivation history of masterwort and its past use in Sweden. Although only few details are known about the history of this taxon, it represents a cultural relict plant of an intentionally introduced species known in Sweden as early as the Middle Ages. In Sweden, the masterwort was mainly used as an ethnoveterinary herbal remedy from the seventeenth to nineteenth centuries. However, medicinal manuals, pharmacopoeias and some ethnographical records indicate that it was once also used in remedies for humans. Today, this species remains as a living biocultural heritage in rural areas, especially on the surviving shielings, which were once used as mountain pastures in Dalecarlia, and at former crofts that were inhabited by cattle owners in the forest areas of southern Sweden.

Does in Vitro and in Vivo Exposure To Medicinal Herbs Cause Structural Cuticular Changes in Haemonchus Contortus?

The health and production of small ruminants in constantly menaced by parasitic infections, especially those caused by the blood-sucking gastrointestinal nematode Haemonchus contortus. The aim of this study was to assess the structural cuticular changes in adult H. contortus induced by the use of extracts from local medicinal plants and to examine their ovicidal activity. Previous studies have confirmed the beneficial effect of herbal mixtures in preventing haemonchosis in lambs by lowering fecal egg production and improving immunocompetence. We exposed adult H. contortus to Herbmix (a mixture of medicinal plants) under in vivo and in vitro conditions for observation by scanning electron microscopy (SEM). For the in vivo observations, adult worms were isolated from the abomasa of experimentally infected lambs from a Herbmix group and a control group. Surface structure did not differ significantly between the exposed and control groups. The ovicidal activity of an aqueous Herbmix extract was assessed in vitro, establishing the inhibition of hatching with an ED₅₀ of 6.52 mg/mL. Adult worms for in vitro examination were isolated from experimentally infected lambs and incubated in Herbmix aqueous extracts for 24 h. SEM observations indicated that none of the worms had prominent ultrastructural changes on their cuticles. This study suggests that previously demonstrated antiparasitic effects of medicinal plants did not negatively affect adult parasites by damaging their external structures.

Seasonal prevalence of gastrointestinal parasites in desert bighorn sheep (Ovis canadensis) in northern Mexico

This study aimed to describe the shedding pattern of gastrointestinal parasite eggs by a wild population of desert bighorn sheep (DBS; Ovis canadensis) in northern Mexico. Seventy-five fresh faecal samples were collected from the ground in each season within an hour after being expelled by these animals. The generalized linear mixed model showed that eggs per gram of faeces were highest in winter (577 ± 399) and lowest in summer (260 ± 198). Generalized linear models revealed that Strongyloides spp. predominated during most seasons with a peak in summer (85% of faecal samples analysed) and the absence of this helminth in winter. Nematodirus spp. was another helminth present in three seasons, with the presence of this nematode in 35% of the faecal samples in spring and 0% in summer. Other parasites in DBS faeces included Bunostomun spp., Trichostrongylus spp., Cooperia spp., Mecistocirrus digitatus, Haemonchus contortus, Chabertia ovina and Eimeria ovinoidalis. There were differences among seasons in the percentage of these helminths and coccidia in faecal samples for all these parasites. It was concluded that helminths egg output in DBS in a semi-arid rangeland is lowest in summer and spring and highest in autumn and winter. Furthermore, it was shown that DBS in the study site do not suffer from severe parasite burden. Therefore, this nematode parasite burden is compatible with the conservation and well-being of this particular population.

Use of agro-industrial by-products containing tannins for the integrated control of gastrointestinal nematodes in ruminants

Previous studies have illustrated that different bioactive legume fodders containing condensed tannins might represent one of the options for integrated sustainable control of gastrointestinal nematodes (GIN) in ruminants, which may help address the worldwide development of resistance to synthetic anthelmintics. More recently, impetus has been given to assess the potential antiparasitic activity of less conventional resources, represented by different agro-industrial by-products (AIBPs). This review presents in vitro and in vivo results obtained with a range of tannin-containing AIBPs of various geographical and botanical origins, namely AIBP of nuts, temperate and tropical barks, carob, coffee and cocoa. They tend to confirm the "proof of concept" for their antiparasitic effects and also for other aspects of ruminant production in an agro-ecological context. Socio-economic aspects of the exploitation of such non-conventional resources are also discussed as potential models of the circular economy, by using waste. The different modes of use of these resources are presented in this review, as well as strengths, weaknesses, opportunities, and threats (SWOT) analyses to illustrate the advantages and limitations of on-farm use.

In Vitro Potential of the Acetone Leaf Extract and Fractions of Psychotria capensis (Eckl.) Vatke (Rubiaceae) to Combat Co-Infection of Tuberculosis and Helminthiasis

Tuberculosis (TB) is a disease of global importance that affects millions of people. Approximately a quarter of the world’s population is currently infected with M. tuberculosis, and about 10% of those infected will develop into active disease, particularly immune compromised individuals. Helminthiasis is of global health importance, affecting over 2 billion people mostly in resource-poor countries. Co-infection with tuberculosis (TB) and helminths (worms) is an emerging global public health concern with both affecting about one-third of the global population. Chronic infection with helminths can result in impaired immune responses to TB as well as enhancing failure to TB therapy and BCG vaccination. Antimycobacterial and anthelmintic activities of the acetone extract and fractions of Psychotria capensis were evaluated, including their in vitro safety. In addition, the anti-inflammatory and immunomodulatory effect of the fractions and crude extract of P. capensis were assessed. Antimycobacterial activity of the extract and fractions was tested against four non-tuberculous mycobacteria (Mycobacterium smegmatis, M. fortuitum, M. aurum, M. bovis BCG) and pathogenic M. tuberculosis H37Rv while the Egg Hatch Assay (EHA) was used for the anthelmintic test on eggs of Haemonchus contortus. Cytotoxicity was determined against Vero kidney cells while in vitro immune modulation via cytokine production was determined on activated macrophages. The minimum inhibitory concentration (MIC) values of the Psychotria capensis acetone extract and fractions ranged from 39 to 1,250 μg/ml with the crude extract and hexane fraction having the best MIC values (both 39 μg/ml). In the EHA, the inhibitory concentration (IC₅₀) ranged from 160 to 630 μg/ml with the hexane fraction having the best activity. The hexane and chloroform fractions were relatively non-toxic with LC₅₀ values of 290 and 248 μg/ml respectively, while the acetone crude extract (64 μg/ml) and n-butanol fraction (71 μg/ml) were moderately toxic. The SI values (LC₅₀/MIC) ranged from 0.1 to 7.4 with the hexane fraction having the highest value against M. smegmatis (7.4). The hexane fraction had the best dual anthelmintic and antimycobacterial activity. This fraction had the best NO inhibitory activity and was the least cytotoxic, indicating that its activity was not due to general metabolic toxicity, with 96.54% cell viability. Pro-inflammatory cytokines such as IL-12p70 were upregulated while IL-10 expression was inhibited by the extracts. Compounds were detected using GC-MS analysis, and in both the crude acetone extract and the hexane fraction was the diterpene neophytadiene, which has anti-inflammatory and antimicrobial activity. Finding alternative or complementary approaches to dealing with TB infections by, amongst other things, reducing the incidence of helminth infestations may lessen the burden of TB, contributing to slowing the spread of multi-drug resistance.

The Effect of Season and Meteorological Conditions on Parasite Infection in Farm-Maintained Mouflons (Ovis aries Musimon)

Due to their limited environment, farm animals are at greater risk of parasitic infection than free-living animals, which also have greater natural resistance to parasitic diseases. The aim of the present study was to determine the influence of season and meteorological conditions (temperature and humidity) on the species composition and dynamics of parasitic infections in farmed mouflons. The study was conducted in a herd of mouflon (n = 40) in an extensive system: the animals remained on pasture all year round. The herd was dewormed twice per year with albendazole. Fecal samples were collected at monthly intervals over three years and tested. The prevalence of infection was defined based on coproscopic methods. For most of the studied protozoans (except for E. parva), a greater prevalence was recorded in spring and summer (i.w. from May to September). Regarding nematodes, Capillaria spp., Nematodirus sp., and the Trichostrongylidae demonstrated a much greater prevalence in winter (i.e., in January and December). Temperature and precipitation were found to be positively correlated with intensity of infection by protozoans. However, maximum air temperature was negatively correlated with infection intensity by some nematodes. The deworming practice used in the herd (selection of substance, date, and method of dosing) did not effectively protect the mouflons against parasitoses. Changes in the microclimate resulted in high extent and intensity of mouflon infection with gastrointestinal parasites. Understanding the dynamics of parasitic infections in mouflons during the year allows the development of an appropriate preventive programme.

A Comparison of the Prevalence of the Parasites of the Digestive Tract in Goats from Organic and Conventional Farms

The aim of the study was to compare the prevalence and intensity of gastrointestinal parasitic infections in goats kept on organic (n = 76) and conventional farms (n = 82). In general, a higher prevalence of some gastrointestinal parasitic infections was found in the conventional farms compared to the organic farms: the mean prevalence of Eimeria spp. was 85.4% in conventional farms and 77.6% in organic farms, that of Fasciola hepatica was 6.10% in conventional farms and 2.63% in organic farms, and that of Moniezia expansa was 31.7% and 17.1%, in conventional and organic farms, respectively. Both farm types demonstrated a similar mean prevalence of nematodes (80.3 vs. 84.2%). Conventional farms demonstrated a significantly higher intensity of infection with E. arloingi, Haemonchus spp., Nematodirus spp. and Moniezia expansa compared to organic farms. They also demonstrated a higher intensity of infection with Eimeria spp. than organic farms. The prophylactic programs used to combat parasitic infections in both types of farms appear ineffective and require improvement. There is a need for goat herds to be covered by ongoing parasitological monitoring. It is also recommended that keepers employ rotational or intensive rotational grazing methods and take care to ensure the hygiene of animal quarters and livestock rooms.

The effects of plant cysteine proteinases on the nematode cuticle

BACKGROUND

Plant-derived cysteine proteinases of the papain family (CPs) attack nematodes by digesting the cuticle, leading to rupture and death of the worm. The nematode cuticle is composed of collagens and cuticlins, but the specific molecular target(s) for the proteinases have yet to be identified.

METHODS

This study followed the course of nematode cuticle disruption using immunohistochemistry, scanning electron microscopy and proteomics, using a free-living nematode, Caenorhabditis elegans and the murine GI nematode Heligmosomoides bakeri (H. polygyrus) as target organisms.

RESULTS

Immunohistochemistry indicated that DPY-7 collagen is a target for CPs on the cuticle of C. elegans. The time course of loss of DPY-7 from the cuticle allowed us to use it to visualise the process of cuticle disruption. There was a marked difference in the time course of damage to the cuticles of the two species of nematode, with H. bakeri being more rapidly hydrolysed. In general, the CPs' mode of attack on the nematode cuticle was by degrading the structural proteins, leading to loss of integrity of the cuticle, and finally death of the nematode. Proteomic analysis failed conclusively to identify structural targets for CPs, but preliminary data suggested that COL-87 and CUT-19 may be important targets for the CPs, the digestion of which may contribute to cuticle disruption and death of the worm. Cuticle globin was also identified as a cuticular target. The presence of more than one target protein may slow the development of resistance against this new class of anthelmintic.

CONCLUSIONS

Scanning electron microscopy and immunohistochemistry allowed the process of disruption of the cuticle to be followed with time. Cuticle collagens and cuticlins are molecular targets for plant cysteine proteinases. However, the presence of tyrosine cross-links in nematode cuticle proteins seriously impeded protein identification by proteomic analyses. Multiple cuticle targets exist, probably making resistance to this new anthelmintic slow to develop.

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

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.

Traditional Latvian herbal medicinal plants used to treat parasite infections of small ruminants: A review

Numerous treatment agents offering prophylaxis against livestock parasites are commercially available. However, because of increasing antiparasitic drug resistance, the increased popularity of environmentally friendly lifestyle choices, and organic farming, there is more demand for new alternatives to livestock anthelmintic control strategies and medications. It is important to develop antiparasitics that are safe, effective, inexpensive, and environmentally safe. Local, traditional herbal plants such as tansy, mugwort, wormwood, and heather may serve as treatments for intestinal parasites of sheep. This overview provides knowledge of traditional Latvian plants with antiparasitic activities to establish a database for further research to develop new herbal antiparasitic drugs.

Comparative anthelmintic efficacy of Arundo donax, Areca catechu, and Ferula assa-foetida against Haemonchus contortus

In the present study, anthelmintic activities of Arundo (A.) donax L., Areca (Ar.) catechu L., and Ferula (F.) assa-foetida L. were determined. Leaves of A. donax L., latex of F. assa-foetida L. and seeds of Ar. catechu L. in different solvent fractions were subjected to in vitro (egg hatch assay; EHA, and adult motility assay; AMA) and in vivo (faecal egg count reduction test; FECRT) tests of anthelmintic activity using Haemonchus contortus model. In the AMA, crude aqueous methanol extracts (CAME) and ethyl acetate fractions of F. assa-foetida at 10 hr post-treatment showed maximum mortality of H. contortus at 12.5-50 mg mL-1. In the EHA, CAME of F. assa-foetida was identified as a potent ovicide based on its low LC50 (16.9 µg mL-1), followed in order by Ar. catechu and A. donax. Results from the FECRT also showed the extract of F. assa-foetida L. to be more effective than those of Ar. catechu L. and A. donax L., against the gastrointestinal parasitic nematodes. Chloroform and ethyl acetate fractions showed better anthelmintic activities against the adult worms in vitro, while CAME of these plants were better than their crude powders in vivo. It is recommended to document and investigate indigenous knowledge of possible medicinal plants to plan scientific trials that may justify their endorsement.

Advances in the discovery and development of anthelmintics by harnessing natural product scaffolds

Widespread resistance to currently-used anthelmintics represents a major obstacle to controlling parasitic nematodes of livestock animals. Given the reliance on anthelmintics in many control regimens, there is a need for the continued discovery and development of new nematocides. Enabling such a focus are: (i) the major chemical diversity of natural products; (ii) the availability of curated, drug-like extract-, fraction- and/or compound-libraries from natural sources; (iii) the utility and practicality of well-established whole-worm bioassays for Haemonchus contortus-an important parasitic nematodes of livestock-to screen natural product libraries; and (iv) the availability of advanced chromatographic (HPLC), spectroscopic (NMR) and spectrometric (MS) techniques for bioassay-guided fractionation and structural elucidation. This context provides a sound basis for the identification and characterisation of anthelmintic candidates from natural sources. This chapter provides a background on the importance and impact of helminth infections/diseases, parasite control and aspects of drug discovery, and reviews recent work focused on (i) screening well-defined compound libraries to establish the methods needed for large-scale screening of natural extract libraries; (ii) discovering plant and marine extracts with nematocidal or nematostatic activity, and purifying bioactive compounds and assessing their potential for further development; and (iii) synthesising analogues of selected purified natural compounds for the identification of possible 'lead' candidates. The chapter describes some lessons learned from this work and proposes future areas of focus for drug discovery. Collectively, the findings from this recent work show potential for selected natural product scaffolds as candidates for future development. Developing such candidates via future chemical optimisation, efficacy and safety evaluations, broad spectrum activity assessments, and target identification represents an exciting prospect and, if successful, could pave the way to subsequent pre-clinical and clinical evaluations.

Gastro-intestinal nematodes in goats in Bangladesh: A large-scale epidemiological study on the prevalence and risk factors

Goats greatly influence the economic sustainability of rural communities. However, parasitic diseases, especially gastrointestinal nematodes (GINs) are a major constraint on profitable small ruminants' production worldwide. During July- 2015 to June- 2016, we conducted a cross sectional study within seven topographic zones of Bangladesh to explore the level of infection and associated risk factors of GINs infections of goats. The study followed standard flotation and modified McMaster techniques. Among 1998 samples from goats; 1241 (62.1%) were found to be infected with one or more species of GINs by fecal examination for nematode eggs. The identified nematodes were strongyles (51.9%), Strongyloides sp. (19.0%) and Trichuris spp. (2.9%). By coproculture, we identified Haemonchus spp., Oesophagostomum spp., Trichostrongylus spp. and Bunostomum spp. in the different topographic zones. According to univariate analysis; young age, other breed than Black Bengal, animals in poor condition, backyard rearing system, muddy housing, illiterate farmers and rainy season were found significantly associated with GINs infections. Besides, other breed than Black Bengal, animals in poor condition, backyard rearing system, muddy housing and illiterate farmers were identified as the risk factors of GINs infections in goats. This is the first detailed epidemiological investigation of GINs of goats in Bangladesh. The epidemiological findings are expected to help formulate effective control strategies against GINs infections in goats by improving health status of animals, management system and education level of the farmers.

Anthelmintic Potential of Cucurbita pepo Seeds on Hymenolepis nana

OBJECTIVE

The main drug used against Hymenolepis nana is praziquantel (PZQ), which causes side effects and toxicity. In contrast, natural extracts have limited side effects and are safer. Past researches have proved that pumpkin seeds are effective as natural antimicrobial and antiparasitic treatment. The present study investigates a natural alternative and less expensive treatment against H. nana using pumpkin seeds.

MATERIALS AND METHODS

Healthy female albino mice were divided into four groups: normal control, infected control with H. nana, infected and treated with PZQ, and lastly, the group infected and treated with pumpkin seeds' extract.

RESULTS

Pumpkin seeds aqueous extract showed a significant reduction (P < 0.05) in the number and length of H. nana adult worms, number and viability of eggs in comparison to the infected control group and PZQ group. Pumpkin seed aqueous extract is proven to be an effective anthelmintic against H. nana.

CONCLUSION

We recommend pumpkin seed extract as a natural alternative, less expensive and safe therapy for H. nana. This is the first study in Saudi Arabia to investigate the therapeutic effect of pumpkin seeds' extract on H. nana.

Nicotine-sensitive acetylcholine receptors are relevant pharmacological targets for the control of multidrug resistant parasitic nematodes

The control of parasitic nematodes impacting animal health relies on the use of broad spectrum anthelmintics. However, intensive use of these drugs has led to the selection of resistant parasites in livestock industry. In that respect, there is currently an urgent need for novel compounds able to control resistant parasites. Nicotine has also historically been used as a de-wormer but was removed from the market when modern anthelmintics became available. The pharmacological target of nicotine has been identified in nematodes as acetylcholine-gated ion channels. Nicotinic-sensitive acetylcholine receptors (N-AChRs) therefore represent validated pharmacological targets that remain largely under-exploited. In the present study, using an automated larval migration assay (ALMA), we report that nicotinic derivatives efficiently paralyzed a multiple (benzimidazoles/levamisole/pyrantel/ivermectin) resistant field isolate of H. contortus. Using C. elegans as a model we confirmed that N-AChRs are preferential targets for nornicotine and anabasine. Functional expression of the homomeric N-AChR from C. elegans and the distantly related horse parasite Parascaris equorum in Xenopus oocytes highlighted some striking differences in their respective pharmacological properties towards nicotine derivative sensitivity. This work validates the exploitation of the nicotine receptors of parasitic nematodes as targets for the development of resistance-breaking compounds.

Ovicidal and larvicidal activity of extracts from medicinal-plants against Haemonchus contortus

The use of medicinal plants (MP) containing bioactive compounds is an alternative strategy to control of parasitic nematode of small ruminants Haemonchus contortus at various stages of their life cycle. The aims of this study were to determine the in vitro anthelmintic activity of both aqueous and methanolic extracts from 13 medicinal plants typical for Central Europe, and to determine quantity of selected plant secondary metabolites (PSMs) in the methanolic extracts. In vitro egg hatch test and larval development tests were conducted to determine the possible anthelmintic effects of methanolic and aqueous extracts of the roots of Althaea officinalis L., Petasites hybridus L. and Inula helenium L.; flowers of Malva sylvestris L. and Chamomilla recutita L.; leaves of Plantago lanceolata L. and Rosmarinus officinalis L.; seeds of Foeniculum vulgare Mill. and stems of Solidago virgaurea L., Fumaria officinalis L., Hyssopus officinalis L., Melisa officinalis L. and Artemisia absinthium L. on eggs and larvae of H. contortus. Ultra-performance liquid chromatography and tandem mass spectroscopy was used for quantifying six PSMs: gallic acid (GA), rutin (RU), diosmin (DI), hesperidin (HE), quercetin (QU) and kaempferol (KA). RU content of the most effective methanolic extracts was in the order: M. sylvestris (9.33 mg/g DM) > A. absinthium (6.10 mg/g DM) > C. recutita (0.42 mg/g DM). The highest concentration of QU (44.8 mg/g DM) and KA (6.59 mg/g DM) were detected in stems of F. officinalis comparing to the other evaluated plants. The most significant (p < 0.05) anthelmintic effects exhibited methanolic extracts of A. absinthium in both in vitro tests (i.e., egg hatch test and larval development test). Additionally, only two methanolic extracts of C. recutita and M. sylvestris were comparable to activity of A. absinthium using the larval development test. Wider spectrum of aqueous extracts exhibited stronger ovicidal activity in comparison to methanolic extracts. The similar trend was observed in evaluating of larvicidal activity of aqueous and methanolic plant extracts.

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.

Targeted and Untargeted Metabolic Profiling of Wild Grassland Plants identifies Antibiotic and Anthelmintic Compounds Targeting Pathogen Physiology, Metabolism and Reproduction

Plants traditionally used by farmers to manage livestock ailments could reduce reliance on synthetic antibiotics and anthelmintics but in many cases their chemical composition is unknown. As a case study, we analyzed the metabolite profiles of 17 plant species and 45 biomass samples from agricultural grasslands in England using targeted and untargeted metabolite profiling by liquid-chromatography mass spectrometry. We identified a range of plant secondary metabolites, including 32 compounds with known antimicrobial/anthelmintic properties which varied considerably across the different plant samples. These compounds have been shown previously to target multiple aspects of pathogen physiology and metabolism in vitro and in vivo, including inhibition of quorum sensing in bacteria and egg viability in nematodes. The most abundant bioactive compounds were benzoic acid, myricetin, p-coumaric acid, rhamnetin, and rosmarinic acid. Four wild plants (Filipendula ulmaria (L.) Maxim., Prunella vulgaris L., Centuarea nigra L., and Rhinanthus minor L.) and two forage legumes (Medicago sativa L., Trifolium hybridium L.) contained high levels of these compounds. Forage samples from native high-diversity grasslands had a greater abundance of medicinal compounds than samples from agriculturally improved grasslands. Incorporating plants with antibiotic/anthelmintic compounds into livestock feeds may reduce global drug-resistance and preserve the efficacy of last-resort drugs.

Tannins in animal nutrition and health – implications for temperate and tropical feeds

This review surveys the nutritional and veterinary effects of tannins on ruminants and provides comparisons with non-ruminants. Tannins are a diverse group of naturally occurring compounds with useful biological effects. However, currently there are difficulties in predicting which tannins produce what effects.

Effects of selected Palestinian plants on the in vitro exsheathment of the third stage larvae of gastrointestinal nematodes

Background

Gastrointestinal parasites are one of the main restrictions to small ruminant production. Their pathological importance is primarily related to the major production losses, in quantity or quality, induced by the direct action of worms. Control of these parasites is based exclusively on the frequent use of anthelmintic drugs. However, the resistance to anthelmintics in worm populations after commercialisation of chemical drugs is now widespread. Therefore, there is a need to find new natural resources to ensure sustainable and effective treatment and control of these parasites. The aim of this study was to evaluate the anthelmintic activity, as minimum inhibitory concentration (IC₅₀ mg/mL), of different plant extracts using larval exsheathment inhibition assay using a two-species but steady population of parasitic nematodes (ca. 20% Teladorsagia circumcinta and 80% Trichostrongylus colubriformis).

Results

The study showed that the ethanolic extracts of 22 out of the 48 plant extracts, obtained from 46 plant species, have an inhibitory effect >50% (at concentrations of 100 mg/mL) on the third stage larvae (L3) of the nematodes exhibited the strongest inhibition activity (94%) with IC₅₀ of 0.02 mg/mL, where other members of the Rhamnaceae family have shown to possess strong anthelmintic activity (70–89%).

Conclusions

Plant extracts are potential rich resources of anthelmintics to combat helminthic diseases. Our results suggest that extracts from Rhamnus elaternus, Epilobium hirsutum, Leucaena leucocephala and Rhamnus palaestinus have promising anthelmintic activity, with potential applications in animal therapeutics and feed.

Therapeutic Potential of Temperate Forage Legumes: A Review

The discovery of bioactive molecules from botanical sources is an expanding field, preferentially oriented to plants having a tradition of use in medicine and providing high yields and availability. Temperate forage legumes are Fabaceae species that include worldwide-important crops. These plants possess therapeutic virtues that have not only been used in veterinary and folk medicine, but have also attracted the interest of official medicine. We have examined here Medicago sativa (alfalfa), Trifolium pratense and T. repens (clovers), Melilotus albus and M. officinalis (sweet clovers), Lotus corniculatus (birdsfoot trefoil), Onobrychis viciifolia (sainfoin), Lespedeza capitata (roundhead lespedeza), and Galega officinalis (goat's rue). The phytochemical complexes of these species contain secondary metabolites whose pharmacological potentials deserve investigation. Major classes of compounds include alkaloids and amines, cyanogenic glycosides, flavonoids, coumarins, condensed tannins, and saponins. Some of these phytochemicals have been related to antihypercholesterolemia, antidiabetic, antimenopause, anti-inflammatory, antiedema, anthelmintic, and kidney protective effects. Two widely prescribed drugs have been developed starting from temperate forage legumes, namely, the antithrombotic warfarin, inspired from sweet clover's coumarin, and the antidiabetic metformin, a derivative of sainfoin's guanidine. Available evidence suggests that temperate forage legumes are a potentially important resource for the extraction of active principles to be used as nutraceuticals and pharmaceuticals.

Integrated parasite management with special reference to gastro-intestinal nematodes

Domestic animals are susceptible to a large number of parasitic diseases, which lead to severe economic losses to livestock industry. So, it is necessary to control parasitic infections in these animals. Control of these helminths is undertaken mostly by anthelmintics, but because of their widespread use there is development of resistance across the globe. However, total dependence on a single method of control has proved to be non-sustainable and cost ineffective in the long term. A combination of treatment and management is necessary to control parasitism so that it will not cause further economic losses to producer as well as to livestock industry. To become practically and ecologically sustainable, parasitic control schemes need to be based on integrated parasite management.

Evaluation of Anthelmintic Activity and Composition of Pumpkin (Cucurbita pepo L.) Seed Extracts-In Vitro and in Vivo Studies

A significant number of studies report growing resistance in nematodes thriving in both humans and livestock. This study was conducted to evaluate the in vitro and in vivo anthelmintic efficiency of Curcubita pepo (C. pepo) L. hot water extract (HWE), cold water extract (CWE) or ethanol extract (ETE) on two model nematodes: Caenorhabditis elegans (C. elegans) and Heligmosoides bakeri (H. bakeri).

METHODS

Raman, IR and LC-MS spectroscopy analyses were performed on the studied plant material to deliver qualitative and quantitative data on the composition of the obtained extracts: ETE, HWE and CWE. The in vitro activity evaluation showed an impact of C. pepo extracts on C. elegans and different developmental stages of H. bakeri. The following in vivo experiments on mice infected with H. bakeri confirmed inhibitory properties of the most active pumpkin extract selected by the in vitro study. All of the extracts were found to contain cucurbitine, aminoacids, fatty acids, and-for the first time-berberine and palmatine were identified. All C. pepo seed extracts exhibited a nematidicidal potential in vitro, affecting the survival of L1 and L2 H. bakeri larvae. The ETE was the strongest and demonstrated a positive effect on H. bakeri eggs hatching and marked inhibitory properties against worm motility, compared to a PBS control. No significant effects of pumpkin seed extracts on C. elegans integrity or motility were found. The EtOH extract in the in vivo studies showed anthelmintic properties against both H. bakeri fecal egg counts and adult worm burdens. The highest egg counts reduction was observed for the 8 g/kg dose (IC50 against H. bakeri = 2.43; 95% Cl = 2.01-2.94). A decrease in faecal egg counts (FEC) was accompanied by a significant reduction in worm burden of the treated mice compared to the control group.

CONCLUSIONS

Pumpkin seed extracts may be used to control of Gastrointestinal (G.I.) nematode infections. This relatively inexpensive alternative to the currently available chemotherapeutic should be considered as a novel drug candidate in the nearest future.

In vitro anthelmintic effect of Tobacco (Nicotiana tabacum) extract on parasitic nematode, Marshallagia marshalli

Because of developing resistance to the existing anthelmintic drugs, there is a need for new anthelmintic agents. Tobacco plant has alkaloid materials that have antiparasitic effect. We investigated the in vitro anthelminthic effect of aqueous and alcoholic extract of Tobacco (Nicotiana tabacum) against M. marshalli. For investigating this effect, we prepared three dilutions of aqueous and alcoholic extract of Tobacco (25, 50 and 75 mg/ml). The worms exposed to extracts for 10 h at 25-30 °C. The buffer PBS used as negative control and 50 mg/ml dilution of Levamisole used as standard reference. In each group, 50 worms were examined. We used an inhibition mobility test for our study. Survival analysis with Cox proportional hazard model was used for data analysis. The result showed that compared with Levamisole 50 mg/ml, dilution of 25 and 50 mg/ml of the aqueous extract had the same anthelminthic effects (P > 0.05), but 75 mg/ml dilution of the aqueous extract and dilution of 25, 50 and 75 mg/ml of alcoholic extract had more anthelminthic effect (P < 0.05). Overall, extracts of Tobacco possess considerable anthelminthic activity and more potent effects were observed with the highest concentrations. Therefore, the in vivo study on Tobocco in animal models is recommended.

Assessing the usefulness of mineral licks containing herbal extracts with anti-parasitic properties for the control of gastrointestinal helminths in grazing sheep – a field trial

One of the alternative methods of parasite control, of particular importance in sustainable farming, is the use of medicinal plants. The specific aim of the present field trial was to assess the anti-parasitic effects of herbal extracts contained in a commercially available lick formulation for sheep. At the outset of this study conducted during the grazing season, all animals were de-wormed and then randomly assigned to one of the two separately kept groups (treatment and control), each consisting of 25 animals (11 ewes and 14 lambs). The treatment group received mineral licks containing the extracts of the plants with anti-parasitic properties, while control animals received standard mineral licks ad libitum. Rectal fecal samples were collected monthly from all animals for the McMaster analyses. There were no significant differences in the prevalence and intensity of helminth infections between the treatment and control groups. Thus, we were not able to ascertain the efficacy of the commercial herbal de-wormer tested for the control of gastrointestinal helminths in grazing ewes and their lambs.

Anthelmintic activity of selected ethno-medicinal plant extracts on parasitic stages of Haemonchus contortus

Background

Parasitic roundworms (nematodes) cause substantial morbidity and mortality in livestock animals globally, and considerable productivity losses to farmers. The control of these nematodes has relied largely on the use of a limited number of anthelmintics. However, resistance to many of these these anthelmintics is now widespread, and, therefore, there is a need to find new drugs to ensure sustained and effective treatment and control into the future.

Methods

Recently, we developed a screening assay to test natural, plant extracts with known inhibitory effects against the free-living worm Caenorhabditis elegans. Using this assay, we assessed here the effects of the extracts on motility and development of parasitic larval stages of Haemonchus contortus, one of the most important nematodes of small ruminants worldwide.

Results

The study showed that two of five extracts from Picria fel-terrae Lour. have a significant inhibitory effect (at concentrations of 3–5 mg/ml) on the motility and development of H. contortus larvae. Although the two extracts originated from the same plant, they displayed different levels of inhibition on motility and development, which might relate to the presence of various active constituents in these extracts, or the same constituents at different concentrations in distinct parts of the plant.

Conclusions

These results suggest that extracts from P. fel-terrae Lour. have promising anthelmintic activity and that more broadly, plant extracts are a potential rich source of anthelmintics to combat helminthic diseases.

In vitro and in vivo anthelmintic activity of Murraya koenigii against gastro-intestinal nematodes of sheep

The present study have been conducted to evaluate the anthelmintic activity of crude aqueous and crude methanolic leaf extracts of Murraya koenigii. Infection of ruminants with gastro-intestinal (GI) parasite has become a worldwide problem. The parasite causes economic losses in a variety of ways. Previously sheep producers relied heavily on anti-parasitic drugs to control gastro-intestinal parasites of the flocks. But due to misuse of these drugs the parasites become resistant to drugs. Thus created interest in studying medicinal plants as an alternative source of controlling the GI parasites. Adult motility assay (AMA) and egg hatch assay (EHA) have been done for in vitro study, and faecal egg count reduction (FECR) assay have been done for in vivo study. The in vitro study revealed anthelmintic effects of M. koenigii on Haemonchus contortus as evident from their paralytic condition and/or death at eight hour post exposure in different concentrations (12.5, 25, 50 mg/ml) of aqueous and methanolic extracts which exhibit to be dose-dependent. Aqueous and methanolic extracts of M. koenigii were found to have low percent inhibitory effect on egg hatching. It may be concluded that M. koenigii showed significant anthelmintic activity.

Anthelmintic activity of Securidaca longepedunculata (Family: Polygalaceae) root extract in mice, in vitro and in vivo

OBJECTIVE

To elucidate the pharmacological bases of oral administration of Securidaca longepedunculata (S. longepedunculata) root extract as an anthelmintic in folkloric medicine.

METHODS

Albino mice were infected with infective third (L3) larval stage of Heligmosomoides polygyrus (H. polygyrus) by esophageal intubation. Following establishment of the adult worms in the intestine, the mice were treated with 0-2 000 mg/kg body weight (bw) of methanolic root extract of S. longepedunculata and 100 mg/kg bw of pyrantel embonate, the reference drug in vivo. Bioactivity and larvicidal effects of the extract were tested by exposing brine shrimps (Artemia salina) to 0.00-1.00 mg/mL and the L3 stage of Heligmosomoidescontortus (H. contortus) and H. polygyrus to 0.00-2.50 mg/mL of the extract in vitro.

RESULTS

The percentage yield of the extract was 7.13% w/w dry matter. The brine shrimps toxicity bioassay resulted in an LC50 of 74.18 μg/mL. The extract had a significant, dose-dependent larvicidal effect on the L3 stage of H. contortus and H. polygyrus with the terminal effect of 75% and 70% at the highest exposure concentrations, respectively. The extract however, did not affect the number of worm eggs per gram (epg) of fecal materials (P<0.05) and total worm burden (twb) of adult H. polygyrus in infected mice. Treatment with pyrantel embonate significant reduced both the fecal egg count and twb to 0 compared to the untreated control (P<0.05).

CONCLUSIONS

These results indicate that S. longepedunculata root extract contains potent bioactive compounds and has larvicidal effect on L3 stage of H. contortus and H. polygyrus, substantiating its use as anthelmintic in alternative medicine.

Diversity of flora used for the cure of equine diseases in selected peri-urban areas of Punjab, Pakistan

BACKGROUND

Plants have widely been used and documented for their therapeutic potential in many parts of the world. There are, however, few reports on the use of plants for the treatment of diseases of equines. To this end, participatory epidemiology and rapid rural appraisal techniques were used to document the plants having pharmacotherapeutic significance against different ailments of equines in selected population of Punjab, Pakistan.

METHODS

A survey was conducted to interview a total of 450 respondents (150 from each of the districts of Faisalabad, Lahore and Sargodha of Pakistan) to collect information about disease recognition of the equines and their treatment on a well - structured questionnaire. A total of 60 plants belonging to 40 families were documented. An inventory was developed depicting detailed information of plants used in treatment of different conditions of equines.

RESULTS

The top ten species of plants used were: Allium cepa, Zingiber officinale, Vernonia anthelmintica, Capsicum annum, Brassica campestris, Trachyspermum ammi, Anethum graveolens, Picrorhiza kurroa, Azadirachta indica, and Citrullus colocynthis. Seeds were the most frequently used (n = 16/60) parts, followed by leaves (n = 12/60) and fruits (n = 11/60) of plants. Based on the combination of different parts of plants used in different ratios and variation in their dose or mode of preparation led to a large number of recipes/remedies against wounds, lameness, bronchitis, colic, anorexia, dermatitis, weakness, parasitism (internal and external), fever, heat stress, urine retention, swelling, toxemia, and indigestion.

CONCLUSIONS

This study generated lot of data on phytomedicinal approach for the treatment of ailments in the equines in some selected areas. It would, therefore, be imperative to expand similar studies in other parts of Pakistan and elsewhere. Moreover, use of the documented plants may be validated employing standard scientific procedures, which may have their application in the drug discovery/development by the pharmaceutical industry.

Developing a rapid throughput screen for detection of nematicidal activity of plant cysteine proteinases: the role of Caenorhabditis elegans cystatins

Plant cysteine proteinases (CPs) from papaya (Carica papaya) are capable of killing parasitic nematode worms in vitro and have been shown to possess anthelmintic effects in vivo. The acute damage reported in gastrointestinal parasites has not been found in free-living nematodes such as Caenorhabditis elegans nor among the free-living stages of parasitic nematodes. This apparent difference in susceptibility might be the result of active production of cysteine proteinase inhibitors (such as cystatins) by the free-living stages or species. To test this possibility, a supernatant extract of refined papaya latex (PLS) with known active enzyme content was used. The effect on wild-type (Bristol N2) and cystatin null mutant (cpi-1(-/-) and cpi-2(-/-)) C. elegans was concentration-, temperature- and time-dependent. Cysteine proteinases digested the worm cuticle leading to release of internal structures and consequent death. Both cystatin null mutant strains were highly susceptible to PLS attack irrespective of the temperature and concentration of exposure, whereas wild-type N2 worms were generally resistant but far more susceptible to attack at low temperatures. PLS was able to induce elevated cpi-1 and cpi-2 cystatin expression. We conclude that wild-type C. elegans deploy cystatins CPI-1 and CPI-2 to resist CP attack. The results suggest that the cpi-1 or cpi-2 null mutants (or a double mutant combination of the two) could provide a cheap and effective rapid throughput C. elegans-based assay for screening plant CP extracts for anthelmintic activity.

Extracts of four plant species used traditionally to treat myiasis influence pupation rate, pupal mass and adult blowfly emergence of Lucilia cuprina and Chrysomya marginalis (Diptera: Calliphoridae)

ETHNOPHARMACOLOGICAL RELEVANCE

Aloe zebrina, Clausena anisata, Erythrina lysistemon and Spirostachys africana are used traditionally in southern Africa to combat and/or treat myiasis, the infestation of the skin of mammals by larvae of a variety of fly species belonging to the arthropod order Diptera.The objective of the study was to establish the in vitro effect of extracts of these plant species on blowfly larvae to ascertain the potential use of these extracts and validate the traditional use.

MATERIALS AND METHODS

Chrysomya marginalis and Lucilia cuprina larvae cultured in the laboratory under controlled conditions were exposed to meat treated with acetone and aqueous extracts of four different plant species. In addition to solvent controls, the effects of the plant extracts were tested at concentrations of 10, 25, 50, 75, 100 and 150 mg/ml. Larval behaviour, larval development and emergence of adult flies were assessed after exposing the larvae to the treated meat. Ivermectin was used as a positive control while acetone and water served as solvent controls. Cytotoxicity of the extracts was determined using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide] assay against C3A human liver cells, bovine dermis cells and Vero African green monkey kidney cells.

RESULTS

An increase in the concentration of the acetone plant extracts resulted in a decrease in the ingestion of meat by larvae, pupal mass and adult emergence rates. The R(2) values for the correlation between dose and pupal mass was 0.92, 0.74 and 0.65 for A. zebrina, C. anisata, and E. lysistemon respectively. For C. anisata and S. africana extracts the increase in the concentration was also associated with the emerging adult flies being smaller. C. anisata was the most toxic plant extract, with an average IC(50) of 39 μg/ml, while E. lysistemon was the least toxic. Vero cells were the most susceptible cell type, with an average IC(50) of less than 100 μg/ml, while the human liver cells were the most resistant to the effect of the plant extracts.

CONCLUSIONS

The results suggest that the plants may contain compounds that interfere with larval feeding and the neuroendocrine control mechanisms in the blowfly. It appears that some of these plant species have the potential to deliver a product that can be used to control myiasis.

Non chemical control of helminths in ruminants: adapting solutions for changing worms in a changing world

Infections with gastrointestinal nematodes (GIN) remain a major threat for ruminant production, health and welfare associated with outdoor breeding. The control of these helminth parasites has relied on the strategic or tactical use of chemical anthelmintic (AH) drugs. However, the expanding development and diffusion of anthelmintic resistance in nematode populations imposes the need to explore and validate novel solutions (or to re-discover old knowledge) for a more sustainable control of GIN. The different solutions refer to three main principles of action. The first one is to limit the contact between the hosts and the infective larvae in the field through grazing management methods. The latter were described since the 1970s and, at present, they benefit from innovations based on computer models. Several biological control agents have also been studied in the last three decades as potential tools to reduce the infective larvae in the field. The second principle aims at improving the host response against GIN infections relying on the genetic selection between or within breeds of sheep or goats, crossbreeding of resistant and susceptible breeds and/or the manipulation of nutrition. These approaches may benefit from a better understanding of the potential underlying mechanisms, in particular in regard of the host immune response against the worms. The third principle is the control of GIN based on non-conventional AH materials (plant or mineral compounds). Worldwide studies show that non conventional AH materials can eliminate worms and/or negatively affect the parasite's biology. The recent developments and pros and cons concerning these various options are discussed. Last, some results are presented which illustrate how the integration of these different solutions can be efficient and applicable in different systems of production and/or epidemiological conditions. The integration of different control tools seems to be a pre-requisite for the sustainable management of GIN infections. This new era of GIN management requires a new paradigm: to achieve enough control to reduce the negative impact of GIN infections enabling an optimum level of production, health and welfare.

Goat-nematode interactions: think differently

Goats (caprine) and sheep (ovine) are infected with the same principal gastrointestinal nematode (GIN) species, which provoke similar pathological changes and economic consequences. However, until now, the majority of data on host-parasite interactions have been accumulated from ovine studies. This article aims to emphasize the need for specific caprine studies. It is hypothesized that, owing to divergent evolutionary processes, sheep and goats have developed two different strategies to regulate GIN infections, respectively, based on immune response versus feeding behavior. Generation of additional comparative data should result in a better understanding of the possible trade-offs between these two basic regulatory processes. Goat studies should also help to avoid past errors in the control of GIN species owing to the lack of relevant information.

Ovicidal and larvicidal activity of crude extracts of Melia azedarach against Haemonchus contortus (Strongylida)

The rapid development of anthelmintic resistance, associated with the high cost of the available anthelmintic drugs, has limited the success of gastrointestinal nematodiosis control in sheep and goats and thus created interest in studying medicinal plants as an alternative source of anthelmintics. The aim of this study was carried out to evaluate the anthelmintic activity of the leaves and seed aqueous and hydro-alcoholic extracts of Melia azedarach L. (Meliaceae) were tested for in vitro ovicidal and larvicidal activity against Haemonchus contortus (Strongylida). Both extracts were evaluated at five concentrations: 12.5, 6.2, 3.12, 1.56, and 0.78 mg/ml. The leaves aqueous and hydro-alcoholic extracts inhibited 99.4% and 100% of the egg hatching and 100% of larval development at 12.5 mg/ml, respectively. In a similar way, the leaves hydro-alcoholic extract was the most active on egg inhibition (ED (50) = 1.97 and ED ( 90 ) = 5.05 mg/ml), leaves and seed aqueous and hydro-alcoholic extracts showed the best inhibition of larval development (ED ( 50 ) = 3.01, 2.43, 3.17, 2.40, and ED ( 90 ) = 10.53, 8.14, 11.94, and 8.19 mg/ml), respectively. These results suggest that utilization of M. azedarach extracts is useful in the control of H. contortus.