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Biomedical subjects

D W Tarry

Publications and source records attributed to D W Tarry.

16 recordsLinked to original sources
PubMed1992

Progress in the British hypodermosis eradication programme: the role of serological surveillance.

The British warble fly eradication programme has resulted in the numbers of infested cattle falling from an estimated four million in 1978 to zero in 1991. In 1982, when about 705 herds were infested the disease was made notifiable, and serological surveillance was begun in 1988. In spring 1991, 227,000 blood samples were tested by using the ELISA technique and no warbled animals were found. In addition no clinical cases were reported during 1991.

Animals↗
PubMed1992

Immunological and feeding studies on antigens derived from the biting fly, Stomoxys calcitrans.

Pairs of rabbits were immunised with three antigenic preparations derived from Stomoxys calcitrans gut, abdominal section and whole flies. Immunoblotting studies demonstrated that a humoral response was mounted against eight antigens from the gut preparation and 12 each from the abdominal and whole fly preparations. In vitro feeding experiments showed higher mortality between Days 4 and 7 in the group of flies which had fed upon blood from rabbits inoculated with the gut derived antigen. This group also produced the lowest percentage of viable eggs (15.5%).

Animals↗
PubMed1991

Transmission of bovine virus diarrhoea virus by blood feeding flies.

Three species of blood-feeding flies (Stomoxys calcitrans, Haematopota pluvialis and Hydrotaea irritans) were fed for five minutes on a bullock persistently infected with bovine virus diarrhoea virus (BVDV) containing 10(4.5)TCID50 non-cytopathic BVDV/ml serum, then subsequently fed on BVDV-free seronegative animals maintained in isolation. Virus was isolated from recipient animals between days 5 and 10 using H pluvialis, and up to 72 hours after transmission with S calcitrans; virus isolation was negative using H irritans. Positive seroconversion results obtained with H pluvialis gave a steadily increasing antibody titre. BVDV was recovered from flies 96 hours (four days) after an infective feed for H pluvialis and S calcitrans, but for two hours only for H irritans.

Animals↗
PubMed1990

The serological incidence of Hypoderma bovis in cattle in England and Wales in spring 1989.

Sera from 152,434 cattle held on 6175 farms in England and Wales were tested for the presence of antibodies to Hypoderma bovis during the 10 weeks starting on February 6, 1989. Thirty-nine positive animals (25.6 animals/100,000 tested) were identified on 21 of the farms (0.34 per cent). In comparison, the survey in 1988 examined 74,502 cattle on 3087 farms and found 29 positive animals (38.9/100,000 tested) on 18 farms (0.58 per cent).

Animals↗
PubMed1990

Cyromazine pour-on for the prevention of cutaneous myiasis of sheep.

The results of trials on eight farms to assess the efficacy of two pour-on formulations containing cyromazine for the prevention of cutaneous myiasis of sheep are presented; data from trials on sheep with larval implants and on sheep kept in cages with adult flies are also reported. The incidence of cutaneous myiasis was reduced by between 87 per cent and 100 per cent for eight weeks when a formulation containing 6 per cent w/v cyromazine was used at an application rate of 60 to 85 mg of active ingredient/kg bodyweight. When a formulation containing 10 per cent w/v was used at an application rate of 50 to 100 mg/kg, the incidence of the condition was reduced by between 90 per cent and 100 per cent for eight weeks. Studies of sheep with larval implants, using the formulation containing 10 per cent w/v cyromazine at 50, 100 and 150 mg/kg bodyweight gave variable results with some animals at each dose rate having lost protection by the seventh week. When sheep were treated with the formulation containing 10 per cent w/v cyromazine at 50 or 100 mg/kg and exposed to adult flies in fly-proof cages they were completely protected for nine and eight weeks, respectively.

Administration, Topical↗
PubMed1989

Serological survey of the incidence of Hypoderma bovis in cattle in 1988.

Sera from 74,502 cattle from 3087 farms in England and Wales were tested for the presence of antibodies against Hypoderma bovis in the spring of 1988. Twenty-nine positive sera were identified on 18 premises and these animals were treated; an examination of 6030 sera taken from 108 neighbouring herds identified another 17 seropositive animals on 10 farms in Devon, Cornwall, Lancashire, Shropshire and Powys, indicating that these counties still harbour populations of warble fly.

Animals↗
PubMed1985

Cattle fly control using controlled-release insecticides.

Field trials were carried out from 1980 to 1984 on the use of a controlled-release pesticidal fly control technique on farms in Sussex, England, with a recurrent infectious keratoconjunctivitis problem related to fly attack. Pesticide impregnated p.v.c. ear-tags provided control of biting and disease-carrying fly species throughout the season. Over 90% control of flies, compared with untreated herds, was attained using 2 tags impregnated with cypermethrin, fenvalerate or flucythrinate, although control using a single tag was unsatisfactory. In all cases infectious keratoconjunctivitis was almost completely eliminated.

Animals↗
PubMed1977

Studies on the feeding patterns of the sheep headfly Hydrotaea irritans (Diptera, Muscidae) in Great Britain.

Serum-precipitin tests carried out on the stomach contents of laboratory maintained and field-caught Hydrotaea irritans showed that a positive result could be obtained for at least seven to 10 days after feeding. Eye, nasal and salivary secretions, even if undiluted, did not give a precipitin response in these tests. Field results from over 3000 flies thus indicate that 20 to 55% of the active fly population had taken a blood meal within the previous 10 days: 75 to 100% of these had fed on cattle blood and 15% or less on sheep blood. Significantly lower feeding levels were obtained from flies collected within plantations, indicating a protracted resting phase in woodland. From "fly feeding areas" high blood-feeding levels were shown from early July, as ovarian development begins. Early feeding rates were similar in both sexes.

Animals↗