Dictyocaulus viviparus and Elaphostrongylus cervi in wapiti

Extract

Sir, — We wish to record the identification of the nematodes Dictyocaulus viviparus (Bloch, 1782) Railliet and Henry, 1907; and Elaphostrongylus cervi Cameron, 1931, from the wapiti (Cervus canadensis).     

Efficacy of ivermectin against Dictyocaulus arnfieldi in ponies

The efficacy of orally administered ivermectin against induced Dictyocaulus arnfieldi infection was evaluated in a controlled study comprising 12 yearling ponies. Treatment with ivermectin paste, at a dose rate of 200 micrograms/kg bodyweight orally once, was 100 per cent effective against both adult and immature or inhibited stages of the horse lungworm. Similar control of second and third instars of Gastrophilus intestinalis was observed and no nematode eggs were present in faeces from seven to 15 days after treatment when the study was terminated.     

Survival of Dictyocaulus viviparus infection on pasture.

Congenital and probable developmental vestibular disease is reported in a litter of English cocker spaniel puppies. The syndrome was marked by loss of balance and ataxia initially, but subsequent compensation has left only one individual with "permanent" head tilt.     

Treatment of inhibited Dictyocaulus viviparus in cattle with ivermectin

Fifteen calves, each infected with approximately 3000 third stage larvae, were used to compare the tendencies of two strains of Dictyocaulus viviparus to inhibit at the fifth larval stage and to evaluate the efficacy of ivermectin. There were notable differences between the strains. While greater than 99% of worms developing from infection with an Alpine strain remained inhibited 42 days after infection, only 0-26% of those recovered following infection with a U.K. laboratory strain were arrested. Neither adult nor immature D. viviparus were present in the lungs of animals treated with ivermectin subcutaneously at 200 micrograms/kg body weight 28 days after infection with the Alpine larvae.     

Cell adherence to larvae of Dictyocaulus viviparus in vitro

Bovine eosinophils survived for up to 48 hours in vitro in a medium of undiluted bovine serum and became adherent to the surface of Dictyocaulus viviparus larvae earlier than other cells found in peripheral blood. Cell adherence was associated with a heat labile factor in normal bovine serum and a heat stable factor in hyperimmune serum. A factor associated with leucocytes in vitro appeared to cause larval immobility. Cells from calves treated with levamisole behaved identically to those from other sources. It is suggested that eosinophils are an important element in host defence against D viviparus infection.     

绵羊丝状网尾线虫病的研究现状

绵羊丝状网尾线虫是绵羊肺线虫病 的主要病原,常呈地方性流行,尤其是对羔羊 的危害比较严重,不仅造成发育障碍,并能使 畜产品质量下降,造成饲料报酬下降、人工投 入浪费等损失,严重时可引起患畜大批死亡, 给畜牧业经济带来的损失是不容忽视的。目 前对这种虫体的了解却不是很多,研究也比 较少,但是这种虫体有着很广阔的研究领域, 有许多问题值得研究探讨。为了能综合地认 识丝状网尾线虫及其疾病,文章主要从形态 学、生活史、流行病学、诊断、治疗与预防等方 面进行了阐述,并对相关问题进行了讨论与 分析。     

Dictyocaulus arnfeldi in foal pneumonia: A case report

A three month old Appaloosa foal was treated for a refractory pneumonia and Dictyocaulus arnfeldi was found as a causative agent. Eosinophilia in a complete blood count alerted the clinician to the possibility of parasitic involvement and the use of a modified Baermann technique produced larvae of Dictyocaulus arnfeldi. Larvacidal doses of thiabendazole resulted in a dramatic clinical improvement and the foal recovered uneventfully with traditional therapy.     

Parenteral vaccination of calves against the cattle lungworm Dictyocaulus viviparus

Protection against challenge with Dictyocaulus viviparus larvae was studied in two groups of calves. The first group was vaccinated orally with an irradiation-attenuated larval vaccine on two occasions, 28 days apart, as recommended by the manufacturer. Each dose contained 1000 larvae. The second group was vaccinated by two subcutaneous injections of vaccine, also 28 days apart. Compared with unvaccinated calves the protection in both groups of vaccinated calves was similar, ie, over 95 per cent reduction in adult worm burdens after an oral challenge of 3000 to 4000 larvae. These results indicate that the passage of irradiated larvae through the intestine and mesenteric lymph nodes is not necessary for the stimulation of a high degree of immunity and opens up the possibility of parenteral vaccination against this and related diseases.