Experimental camelpox infection in vaccinated and unvaccinated dromedaries

Four dromedaries were infected with a virulent camelpox virus strain which was isolated from the lung of a Saudi Arabian camel. The camels which were infected intradermally and subcutaneously developed severe generalized camelpox. One of these camels had to be euthanized on humane grounds and the second one died 13 days after being infected. This dromedary also developed internal pox. Neither dromedary showed camelpox antibodies before infection. The other two camels which had been vaccinated with Ducapox 6 years prior to the viral challenge did not develop any clinical symptoms when given 5 ml of the field virus intravenously and intramuscularly. They seroconverted after the challenge. Although only two camels were used for this trial, the results indicate that a single dose of Ducapox can protect 1-year-old camels from camelpox infection for several years.     

The incidence of Dictyocaulus viviparus infections in cattle in the Netherlands

Summary

The Enzyme Linked Immunosorbent Assay (ELISA) provides a very efficient technique for detecting antibodies against Dictyocaulus vivparus in calves. Although low level cross reactions were found in animals with gastrointestinal nematodes, the specificity and sensitivity of the technique are sufficient for herd diagnosis of lungworm infections and for survey work. This conclusion is reached on the basis of artificially and naturally infected calves. ELISA titres correlate well with Indirect Haemagglutination titres, parasitological findings, and clinical observations.     

Persistent anthelmintic activity of topically administered ivermectin in red deer (Cervus elaphus L.) against lungworms (Dictyocaulus viviparus)

A controlled trial was conducted to evaluate the persistent anthelmintic effect of ivermectin as a topical treatment at 500 microg/kg against induced infection with lungworm (Dictyocaulus viviparus) in red deer (Cervus elaphus). The results showed a highly significant (p <0.01) anthelmintic activity for at least 28 days against a newly acquired infection with Dictyocaulus viviparus (>99% efficacy).     

Persistent anthelmintic activity of topically administered ivermectin in red deer (Cervus elaphus L.) against lungworms (Dictyocaulus viviparus)

A controlled trial was conducted to evaluate the persistent anthelmintic effect of ivermectin as a topical treatment at 500 μg/kg against induced infection with lungworm (Dicryocaulus viviparus) in red deer (Cervus elaphus). The results showed a highly significant (p < 0.01) anthelmintic activity for at least 28 days against a newly acquired infection with Dictyocauus viviparus (> 99% efficacy).     

Sero-epidemiological survey of Dictyocaulus viviparus infections in first-season grazing calves in The Netherlands

A sero-epidemiological survey of Dictyocaulus viviparus infections in calves was carried out using an enzyme-linked immunosorbent assay. Infection level with D viviparus was correlated with farm, herd and management characteristics. At least 75 per cent of the herds were infected with D viviparus. Calves on zero-grazing farms were infected at a lower level than calves grazing pasture. No regional differences in infection rate were observed. On 15 per cent of the farms calves had clinical husk while 51 per cent of farms had experienced husk in the past. A higher level of infection was seen when calves were housed later in the autumn. The number of calves grazing together and the stocking rate had a significant positive influence on the level of infection. No significant difference in the occurrence of clinical husk was observed between calves vaccinated against lung-worm disease and calves not vaccinated against the disease.     

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).     

Dictyocaulus infection in farmed red deer (Cervus elaphus)

Post mortem examination of red deer calves on a deer farm situated on hill ground in north-east Scotland revealed infection by a lungworm morphologically similar to Dictyocaulus viviparus. Trials were conducted to monitor the natural development of D viviparus infection in red deer, to investigate the value of a commercial lungworm vaccine and to evaluate methods of treating clinical cases. The findings indicate that the syndrome may be less apparent in red deer than it is in cattle, protection might be gained by vaccination and that housing and medication provide useful therapy. The extent of clinical disease is likely to depend on the general health, bodily condition and nutritional status of the animals versus the weight of infection acquired from the pasture. However, various factors can affect both sides in this confrontation.     

Dictyocaulus species: cross infection between cattle and red deer

Aim: To discover whether cross infection between red deer (Cervus elaphus) and cattle is possible with either a bovine isolate of the cattle lungworm, Dictyocaulus viviparus, or with a cervine isolate of the lungworm, Dictyocaulus eckerti which is thought to be maintained primarily in deer. Method: Twelve cattle and 12 red deer were reared parasite-free from birth. At 3-4 months of age, half of each species (n=6) were experimentally infected with D. viviparus and the other half with D. eckerti. The course of infection was monitored for 34 days, after which the animals were slaughtered and the lungs removed to assess levels of infection. Results: Faecal larval counts demonstrated that patent Dictyocaulus infections occurred in all groups. At necropsy, adult worms were found in the lungs in all groups except the cattle that were infected with D. eckerti. The largest numbers of adult worms were found in the red deer infected with D. eckerti. Conclusion: It was demonstrated that both cattle and red deer could be infected with either D. viviparus or D. eckerti. However, D. eckerti larvae that originated from deer established more successfully in deer and D. viviparus larvae that originated from cattle established more successfully in cattle.     

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.     

Dynamics of infections with gastrointestinal parasites and Dictyocaulus viviparus in dairy and beef cattle from Costa Rica

A longitudinal survey was carried out to determine and describe the prevalence and intensity of gastrointestinal parasite infections and Dictyocaulus viviparus in a dairy and a beef cattle farm of two different ecological zones in Costa Rica. The influence of anthelmintic treatment, age and meteorological factors (rainfall, minimum and maximum temperatures) on gastrointestinal nematodes and D. viviparus counts was determined. Calves were subjected to monthly sampling of feces and blood between April 2002 and March 2003. Coprological techniques were used to detect gastrointestinal helminthes, protozoan and D. viviparus. Blood samples were analyzed for antibodies to D. viviparus by ELISA. The most prevalent gastrointestinal parasites detected on both farms (dairy cattle, A; beef cattle, B) were Eimeria spp. (94.7%, 93.7%), Strongylidae (75.0%, 81.4%), Buxtonella sulcata (38.0%, 21.6%) and Strongyloides papillosus (29.8%, 31.7%), whereas Moniezia benedeni (4.8%, 9.1%), Trichuris spp. (7.3%, 13.2%), Toxocara vitulorum (0.0%, 1.8%) and Entamoeba bovis (2.5%, 1.1%) were less prevalent. Mean fecal egg counts (FEC) showed highest values of Strongylidae in April, May and July (>335.3 eggs/g feces) on farm A, and April, May and August (>304.3 eggs/g feces) on farm B. S. papillosus presented low FEC throughout the year on farm A, on farm B the highest values were obtained in April (303.0 eggs/g feces). Trichuris spp. presented maximum FEC values in May (328.6 eggs/g feces) on farm A and in June (157.5 eggs/g feces) on farm B. Treatment and age had significant influence on infection intensity of Strongylidae (farms A and B), S. papillosus (farms A and B) and Trichuris spp. (farm A). Rainfall had significant effect on S. papillosus (farms A and B) and Trichuris spp. (farm B). Maximum temperature showed significant effect on S. papillosus (farm A) and Trichuris spp. (farms A and B). Minimum temperature had significant influence on Strongylidae (farm A), S. papillosus (farms A and B) and Trichuris spp. (farm B). Haemonchus spp. (57%, 66%) and Cooperia spp. (30.0%, 30.7%) were the most prevalent genera identified by coproculture on both farms, in contrast, Trichostrongylus spp. and Oesophagostomum spp. were less frequent. Patent lungworm infections were low on both farms (10.8%, 1.8%). On farm A, high prevalence of antibodies against D. viviparus was determined only at the beginning of the study, in contrast, on farm B the seroprevalence fluctuated throughout the year. Treatment, age and maximum temperature had significant effect on D. viviparus counts on farm A, but not on farm B.     

Effect of ivermectin and oxfendazole on shedding of larvae of the lungworm (Dictyocaulus viviparus) by red deer (Cervus elaphus)

Thirty eight newly weaned hinds were randomly allocated to one of two equal groups. One group received ivermectin, the other, oxfendazole at dose rates of 0.2 mg/kg and 4.5 mg/kg, respectively. All deer were drenched four times and were grazed on pasture. Both anthelmintics reduced D. viviparus faecal larval counts to low levels 20 days after dosing, but the mean larval output and the proportion of deer shedding D. viviparus larvae at 27 and 33 days after treatment, were significantly lower in the ivermectin treated group. There was no significant difference in weight gain between the two groups throughout the trial. This study suggests that ivermectin prevents reinfection with D. viviparus for approximately 14 days longer than oxfendazole.