Biomedical subjects

B L Swift

Publications and source records attributed to B L Swift.

17 recordsLinked to original sources

PubMed1983

Bovine anaplasmosis: elimination of the carrier state with injectable long-acting oxytetracycline.

Long-acting oxytetracycline was administered intramuscularly (20 mg/kg) at 3-day intervals to each of 16 naturally infected Anaplasma marginale carrier beef cows; 8 of the 16 cows were given 3 injections and the other 8 cows were given 4 injections. Four cows seropositive for A marginale served as untreated controls. Rapid card agglutination and complement fixation tests were performed 5 times during the 130-day posttreatment period. All treated cows became negative to both serologic procedures, whereas control cows remained seropositive. Three splenectomized calves that received pooled blood from the treated cows, 120 days following treatment, remained free of anaplasmosis for 60 days following inoculation. One splenectomized calf that received blood from the control cows developed anaplasmosis. It was concluded that long-acting oxytetracycline can be used to eliminate the naturally acquired carrier state of anaplasmosis in cattle.

Anaplasmosis↗

PubMed1983

Cause and pathogenesis of middle ear infection in young feedlot cattle.

Two populations of feedlot cattle--weaned calves and yearlings--suffered otitis media. In calves the disease was acute and epizootic and had a prevalence of about 400 cases per 2000 cattle, whereas in yearlings, it was chronic and sporadic and had a prevalence of 1 case per 2000 cattle. Clinical signs were facial paralysis, otorrhea, and head tilt. The middle ears from 64 dead calves and 22 dead yearlings were examined. Calf ears had acute infection, with exudate in air cells and rupture of tympanic membranes. Yearling ears had chronic infection, with exudate in air cells, rupture or destruction of tympanic membranes, and necrosis of air cell partitions. Mixtures of Pasteurella multocida and Corynebacterium pseudotuberculosis were isolated from diseased ears, but Pasteurella multocida predominated in acute infections and Corynebacterium pseudotuberculosis predominated in chronic infections.

Acute Disease↗

PubMed1983

Encephalitic sarcocystosis in a newborn calf.

Sporozoan schizonts were seen in histologic sections of cerebrum from a Hereford calf that died immediately after birth. Schizonts appeared in endothelial cells of small vessels in the gray and white matter. Rosette and palisade configurations of merozoites in schizonts, as well as the size of schizonts (15 to 40 X 21 microns) and merozoites (8 microns), resembled Sarcocystis stages described in cattle, and differentiated the organisms from Toxoplasma that infects nerve cells and undergoes endodyogeny. Specific identification of the infecting agent was not successful because tests of sera from the calf were not possible. Developmental, morphologic, and ultrastructural differences in schizogonic stages of the heteroxenous sporozoan species infecting cattle are poorly known and are presently unreliable criteria for species identification. Encephalitis, meningitis, and necrosis occurred in cerebral, cerebellar, and brain stem gray and white matter infiltrated with plasmacytes, lymphocytes, and macrophages. Microthrombi were often seen in small blood vessels within the reaction foci. Herd-mate sera tested against S cruzi were negative. The herd from which the calf was born was exposed to a variety of free-ranging domestic, feral, and wild scavengers with free access to dead range animals. Consequently, the cattle were undoubtedly exposed to infective cysts in feed or water contaminated by feces from carnivores.

Animals↗

PubMed1982

Middle ear infection in feedlot lambs.

Of 133 feedlot lambs that died and were necropsied, 67 had normal lungs and 66 had pneumonic lungs. The middle ears of all lambs were opened by a specified technique. Of the 67, 8 (12%) had otitis media, and of the 66, 26 (39%) had otitis media. The difference in prevalence in the 2 groups was highly significant (P less than 0.005). In acute stages, the mucosae of tympanic cavities and tympanic membranes were inflamed and the cavities contained fluid, whereas in later stages lumens were partially filled with exudate. In chronic stages, however, exudate remained in lumens and mucosae were thick and rough. None of the tympanic membranes was ruptured, and none of the external acoustic meatuses contained exudate. The infected ears of 24 lambs were cultured and Pasteurella haemolytica was isolated from 18, and P multocida from 3. The infections probably ascended from the pharynx through the auditive tubes into the tympanic cavities.

Animals↗

PubMed1982

Ram epididymitis: A clinical report.

Two hundred and five ram lambs originating from several sources were assembled for a ram performance trial. All rams were immunized with a commercial Brucella ovis bacterin. Four rams developed clinical evidence of epididymitis during the 150 day trial. Actinobacillus seminis was identified as the causative agent.

Journal Article↗

PubMed1982

Ischemia: a cause of hepatic telangiectasis in cattle.

We histologically examined (i) 73 bovine livers condemned by packing house inspectors for telangiectasis, (ii) 15 bovine livers passed by the same inspectors as normal, and (iii) 8 livers from cattle given an injection into their mesenteric veins: 6 with a suspension of agar particles containing viable Haemophilus somnus and 2 with diluent only. The injected cattle were killed and necropsied 2 to 12 days after the inoculations. Of the 73 telangiectatic livers, 57 (78%) had thrombosed and occluded or contracted and empty portal veins (venopathies), whereas 1 of the 15 normal livers contained one microscopic focus of telangiectasis and nearby venopathy. Of the 6 livers injected with suspended particles, all had venopathies and telangiectasis and the 2 control livers had neither.

Animals↗

PubMed1979

Testicular degeneration and libido loss in beef bulls experimentally inoculated with Anaplasma marginale.

Four sexually mature virgin beef bulls were inoculated with whole blood from a known Anaplasma marginale carrier. All four bulls became infected and experienced some degree of anemia and testicular degeneration, while uninoculated controls remained normal. Testicular degeneration was confirmed by electron microscopy, histopathology, and semen evaluation. Further observations established that the inoculated bulls exhibited a loss of libido, while controls reacted in a normal manner to a cow in estrus. Anaplasma marginale was not present in semen of inoculated bulls.

Journal Article↗

PubMed1978

A bovine herpesvirus isolated from sheep.

A viral agent was isolated from the trachea of a lamb that was suffering from a respiratory disorder. The physical and chemical properties of the isolates are characteristic of the herpesvirus group. It contains DNA in its virion, is ether sensitive, acid labile at pH 3.0 and heat labile at 56 degrees C after five minutes. The cytopathology observed provided further evidence of a herpesvirus isolate. The neutralization of the infectivity of the isolate with antiserum to bovine herpesvirus 1 is evidence that it should be considered an isolate of bovine herpesvirus 1. It is concluded that this is a report of a bovine herpesvirus infection in sheep.

Animals↗

PubMed1977