Resistance to a triple combination of broad-spectrum anthelmintics in naturally-acquired Ostertagia circumcincta infections in sheep

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To the veterinary practitioner, the challenge of managing a cat with renal failure is very real. The specific goals of therapy are to:     

Mineral testing — The approach depends on what you want to find out

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Comments have been made by veterinary practitioners and farmers on the appropriateness of the MAF Quality Management animal health laboratory mineral reference ranges. These ranges are designed to determine if a group of animals will respond to supplementation at the time of sampling. There are other reasons for sampling animals and this will affect the way these ranges are interpreted. We consider this fact is not clearly understood and is at least part of the reason for the questions being asked.     

A field study on the anthelmintic resistance of Parascaris spp. in Arab foals in the Riyadh region,Saudi Arabia

Background: In the last decade, Parascaris spp. resistance to anthelmintics has been recorded in many countries. In Saudi Arabia, there are limited data available on Parascaris spp. resistance to anthelmintics.

Objective: To determine the current status of ivermectin, abamectin and praziquantel combined, and fenbendazole resistance to Parascaris spp. in horses in Saudi Arabia.

Methods: Three hundred and forty-one foals from eleven different farms were examined by faecal egg count (FEC). The foals were all Arab horses aged 17.2 ± 4.5 (SD) months. Ivermectin (n = 46 foals), abamectin and praziquantel combined (n = 46), and fenbendazole (n = 46) were administered on day 0 and faeces were collected on day 14. The study comprised 41 untreated foals as controls. Animals that have FEC of ≥100 eggs per gram (EPG) were used to measure anthelmintic efficacy. Parascaris spp. populations were considered susceptible when faecal egg count reduction (FECR) was ≥95% associated with a lower 95% confidence limit (LCL) >90%, suspected resistant when FECR ≤90% or LCL <90% and resistant when FECR <90% and LCL <90%.

Results: Prevalence of Parascaris spp. infection was 53% (179/341 horses). Anthelmintic resistance to Parascaris spp. were highest following fenbendazole (55% of farms and 65% of foals) and to a lower extent following ivermectin or the combination of abamectin and praziquantel which comprised 27% of farms (and 46% of foals) and 18% of farms (and 10% of foals), respectively.

Conclusion: These data indicate that anthelmintics-resistant Parascaris spp. populations are present on horse farms in Saudi Arabia.     

Efficacy and toxicity of praziquantel in helminth‐infected barbel (Barbus barbus L.)

This study evaluated efficacy and toxicity of the pyrazinoisoquinoline anthelmintic praziquantel (PZQ) in barbel infected with metacercariae of Diplostomum spathaceum and adult Pomphorhynchus laevis, and assessed antioxidant biomarkers and the lipid peroxidation response in juvenile barbel post‐treatment. The estimated 96‐hr LC50 of PZQ was 28.6 mg/L. For evaluation of efficacy, barbel naturally infected with D. spathaceum were exposed to a 10 and 20 mg/L PZQ 4‐day bath treatment. Both concentrations were 100% effective against D. spathaceum and significantly (p < .01) affected the activity of catalase, superoxide dismutase, glutathione reductase and glutathione‐S‐transferase as well as levels of reduced glutathione in liver and muscle. The efficacy of orally administered PZQ was assessed in adult barbel naturally infected with P. laevis. Fish were administered 10, 30 and 50 mg/kg of body weight and examined via gut dissection after 6 days. The 50 mg/kg dose significantly decreased the intensity of infection. Praziquantel is a feasible bath treatment for barbel infected with D. spathaceum and has potential for oral treatment of broodfish infected with P. laevis.     

The anthelmintic effects of five plant extracts on the viability of Parascaris equorum larvae

Ascariasis is a very common parasitic disease in equids, especially in young horses. Despite the use of anthelmintic drugs, resistance has been frequently reported in populations of Parascaris equorum. As a result, herbal preparations are proposed for current control strategies. In this study, a modified method was used for hatching the eggs of P. equorum. After hatching, the effects of methanolic extract of Artemisia dracunculus, Eucalyptus camadulensis, Mentha pulegium, Zataria multiflora and Allium sativum (garlic) were investigated on the recovered larvae. For each extract, the anthelmintic effects of different concentrations (50, 75, 100 and 125 mg/mL) were evaluated at 0, 10, 20, 30 and 40 min after the challenge. The results showed that our modifications to the older method could enhance the hatching rate for the eggs of P. equorum (to an average of 98%). Potassium dichromate was also demonstrated in this study to be a favourable medium during embryonation. In addition, all the concentrations of A. dracunculus and M. pulegium and higher levels (≥100 mg/mL concentrations) of Z. multiflora extracts had significant lethal effects on larvae from the first to the fourth 10 min of the experiment. In contrast, E. camadulensis and A. sativum had not marked effects on larvae viability at any time of the challenge. In conclusion, our data suggest that A. dracunculus, M. pulegium and Z. multiflora have potential to be used as anthelmintic for the control of ascariasis in equid host; however, these effects remain to be confirmed through in vivo studies.     

不同驱虫药物对奶山羊消化道线虫驱虫效果研究

本研究旨在观察不同驱虫药物对奶山羊消化道线虫的驱虫效果,为今后寄生虫病的防治筛选更好的驱虫药物。选取奶山羊96只,分3组,每组32只,分别投喂伊维菌素注射液、芬苯达唑粉和伊维菌素芬苯达唑预混剂3种驱虫药物,采用饱和盐水漂浮法和麦克马斯特法检测驱虫前后线虫的感染情况。结果发现:伊维菌素注射液组虫卵转阴率为6.25%;芬苯达唑粉剂组虫卵转阴率为31.25%;伊维菌素芬苯达唑预混剂组虫卵转阴率为50.00%。驱虫前后感染强度伊维菌素注射液组差异显著(P<0.05),芬苯达唑粉剂组差异极显著(P<0.01),伊维菌素芬苯达唑预混剂组差异极显著(P<0.01)。因此,建议采用伊维菌素芬苯达唑预混剂作为奶山羊消化道线虫首选驱虫药物。     

羊附红细胞体解离方法的比较研究

本试验为建立一种高效的羊附红细胞体解离方法,采集红细胞感染率大于90%的阳性抗凝血,分别应用水浴法和药物体外驱虫法对羊附红细胞体进行解离,观察分离前后附红细胞体感染率、红细胞感染强度、附红细胞体数、杂质含量和附红细胞体的运动性5项指标;提取附红细胞体抗原,制备全蛋白悬液,测定蛋白质含量,比较解离效果。将两种方法制备的羊附红细胞体抗原全蛋白进行SDS-PAGE试验,观察条带是否一致。结果显示,200 mL血液中加入1 mL双向红莲灭,4℃作用36 h,即可达到较好分离效果。与水浴法相比,解离后,红细胞感染率和感染强度明显下降,蛋白含量增加,收率高,纯度好。SDS-PAGE结果显示,体外驱虫法所制的羊附红细胞体抗原全蛋白悬液,其抗原蛋白带与水浴法相同,因此可用于粗制羊附红细胞体抗原。     

Efficacy of Albendazole and Levamisole against Gastrointestinal Nematodes of Sheep and Goats in Morogoro,Tanzania

A study was conducted to determine the efficacy of albendazole after it had been withdrawn from use due to the development of resistant strains of nematodes about ten years ago. The study also aimed to determine the present efficacy of levamisole, which had been recommended to replace albendazole. On one farm, the sheep and goats were divided into two groups, one group of each serving as the untreated control, while the other was treated with levamisole. The sheep on the other farm were divided into three groups, one serving as the untreated control group, the second being treated with levamisole and the third being treated with albendazole. Faecal samples were collected one day before treatment, and again 10 days after treatment. Anthelmintic efficacy was determined by the faecal egg count reduction test. Ten days after treatment, the sheep treated with levamisole on the first farm had a 98% reduction in faecal egg count, with a 95% confidence limit of 76%. The goats on the same farm had a 97% reduction in faecal egg count, with a 95% lower confidence limit of 81%. At the second farm, 10 days after treatment, sheep treated with levamisole had a 99.4% reduction in faecal egg count, with a 95% lower confidence limit of 88.9%, whereas the sheep treated with albendazole only had a 59.4% reduction in faecal egg count, with a 95% lower confidence limit of –19.6%. The study indicated that the gastrointestinal nematodes of sheep at the Department of Animal Science and Production farm were still resistant to albendazole about ten years after this anthelmintic had been withdrawn from use. A reduced efficacy of levamisole was suspected.