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Biomedical subjects

S P Sahu

Publications and source records attributed to S P Sahu.

17 recordsLinked to original sources

Susceptibility of mink to certain viral animal diseases foreign to the United States.

Mink (Mustela vison) were inoculated with viruses: African horse sickness (AHS), African swine fever (ASF), bovine herpes virus II (BHV2), foot-and-mouth disease (FMD), goat pox (GP), hog cholera (HC), peste des petits ruminants (PPR), rinderpest (RP), swine vesicular disease (SVD), vesicular exanthema of swine (VES) and vesicular stomatitis (VS). Their susceptibility was measured by development of clinical signs, virus isolation and detection of precipitin and/or virus neutralizing antibodies. SVD virus produced a lesion in one mink. Virus was isolated from mink inoculated with SVD, FMD and BHV2. Neutralizing and/or precipitin antibodies were detected in mink inoculated with ASF, FMD, GP, RP, SVD and VS viruses. Mink were not susceptible to AHS, HC, PPR and VES viruses.

African Horse Sickness

Survival of contagious equine metritis bacteria in transport media.

Survival of bacteria that cause contagious equine metritis (CEM) was evaluated in Amies modified transport (AMT) medium, in AMT medium with charcoal, and in Stuart transport medium at 37, 22, 4, and -70 C. The CEM bacteria suspended in transport media survived at 22, 4, and -70 C for longer periods in AMT medium with charcoal than they did in AMT and Stuart transport media. In 1 day, the number of bacteria in exudate stored in the absence of any transport medium decreased 15-fold at 22 C and twofold at 4 C. The CEM bacteria were isolated from exudate on cotton-tipped swabs from all three transport media at 4 and -70 C on day 10, the termination of the experiment. However at 4 C, the survival of CEM bacteria was greater in AMT medium with charcoal than it was in AMT and Stuart transport media.

Animals

Contagious equine metritis: clinical description of experimentally induced infection.

Contagious equine metritis was reproduced experimentally in 6 pony mares. The disease was characterized by rapidly developing cervicitis and by varying amounts of exudate. The exudate, apparent as early as 48 hours after inoculation, drained from the cervix as a tenacious, mucopurulent discharge for several days, then rapidly disappeared. In all mares, the clinical disease cleared within several weeks of inoculation, without treatment.

Animals

An ultrastructural study of avian synovium infected with an arthrotropic Mycoplasma, Mycoplasma synoviae.

Live Mycoplasma synoviae cells in agar base medium were inoculated intravenously into 10 2-week-old chickens. Joint tissues were collected over a 3-week period for light and transmission electron microscopy. In infected chickens, membrane-bound vacuoles of intact M. synoviae cells were seen in the cytoplasms of adipose cells. Cytoplasmic lipid-containing inclusions had accumulated in enlarged fibroblasts in tendon sheaths and loose connective tissue. Synovial cells had proliferated and contained increased amounts of granular endoplasmic reticulum and lipid inclusions. No abnormalities were seen in control chickens. Infected chickens were positive and control chickens were negative for rheumatoid factor activity by two serological tests: tanned cell hemagglutination and latex agglutination tests.

Animals

Avian viral arthritis: antigenic types and immune response.

Serums from broiler breeders of an integrated broiler operator were examined for precipitin antibodies using antigens prepared from preliminary reovirus serotypes represented by WVU-2937, Reo-25, Reo-59, and Fahey-Crawley virus. The precipitin antibodies were present in most of the flocks. Virus neutralization tests indicated that the reovirus responsible for viral arthritis represented by WVU-2937 was not present in the breeder flocks, but antibodies to Reo-25, Reo-59, and the Fahey-Crawley viruses were present.

Animals

Comparison of the characteristics of avian reoviruses isolated from the digestive and respiratory tract, with viruses isolated from the synovia.

Two-week-old gnotobiotic chicks were inoculated in the foot pad with viruses isolated from synovia and synovial membrane-WVU 1464-29H, WVU 1675, WVU 2937, WVU 2986, and WVU 71-212; from digestive tract-reoviruses 24, 25, and 59; or from respiratory tract-reovirus Fahey-Crawley (FC). All viruses induced swelling of the foot pad and inflammatory changes of synovial membrane. Serum from virus-infected chicks had a common agar gel precipitin (AGP) line. On the basis of the plaque-reduction test in primary chicken kidney (PCK) cells, the viruses were classified into 4 major serotypes. All viruses produced cytopathic effects (CPE) in primary chicken tissue cultures. Other than reovirus FC and WVU 1464-29H, all viruses produced CPE in the Vero cell line.

Animals

Synthesis of fibroma viral deoxyribonucleic acid complexes in rabbit kidney cells.

Cytoplasmic extracts of primary rabbit kidney cells inoculated with fibroma virus revealed 2 peaks of DNA complexes (120S and greater than or equal to 410S) in a linear sucrose gradient. Pulse-chase experiments demonstrated a shift in the gradient profile of lighter complexes toward heavier complexes. Synthesis of DNA complexes was inhibited by adding puromycin or actinomycin D. The DNA from virus-infected cultures hybridized 7 to 9 times greater with fibroma virus DNA than did the DNA from noninfected cultuures. The DNA complexes became increasingly resistant to deoxyribonuclease digestion as a function of time during viral growth cycle and produced tumors in rabbits.

DNA, Viral

Characterization of avian reoviruses isolated from the synovia and breast blister.

Reoviruses Texas, S 1133, UMI 203, and WVU 2937 induced swelling of the foot pad and inflammatory changes in the synovial membranes when inoculated in the foot pad of 2-week-old gnotobiotic chicks. From differences in virus neutralization as measured with geometric mean (R) value, all four viruses are subtypes of a single serotype. The cell-associated and cell-released virus growth curves were similar, with a lag phase of about 15 hours and a log phase of 15 to 21 hours. Viral RNA synthesis reached a peak in 5 hours and was active at 14 hours but not at 18 hours. In 90 minutes at 60 C the titer of each virus had decreased about 4 logs.

Animals

Evaluation of broiler breeder flocks for nonspecific Mycoplasma synoviae reaction.

Serums from 65 broiler breeder flocks were evaluated for mycoplasma synoviae (MS) and Mycoplasma gallisepticum (MG) antibodies by serum plate agglutination (SPA), micro hemagglutination-inhibition (HI), and agar gel precipitin (AGP) tests. The nonspecific SPA reaction in serum from breeder flocks was eliminated by diluting the serum 1:5 in phosphate-buffered saline (PBS), pH 7.2, before testing provided that the MS antigen reacted with 1:10 dilution of the MS antiserums. The nonspecific SPA reaction was confirmed by negative HI and AGP reactions. Wehn specific MS reactions occurred, the serums showed a micro HI titer of 1:80 or greater and an AGP line, and MS was isolated from the upper respiratory tract of infected birds. Serums from experimental birds on Aureomycin, 200 g/ton of feed, were positive on the SPA test but were negative for micro HI and AGP tests. MS was isolated from these birds. Nonspecific SPA MG reaction occurred in many of the flocks which were negative by MG HI and AGP tests.

Agglutination Tests

Use of the agar-gel precipitin test to evaluate broiler breeder and commercial layer flocks for Mycoplasma gallisepticum infection.

In the absence of Mycoplasma gallisepticum (MG) isolation, the importance of agar-gel precipitin (AGP) tests along with microhemagglutination-inhibition (mHI) and serum plate agglutination (SPA) tests for the evaluation of poultry flocks for MG infection was demonstrated. A good correlation between AGP, mHI, and SPA tests for the early confirmation of MG in a flock was observed, except for the breeder flocks from which WVU 907 was isolated. The serums of such breeder flocks were positive for SPA and AGP test but negative for the mHI test. Isolation of MG for confirmation of the status of the flock was unsatisfactory in the later stages of infection or when nonpathogenic organisms were present in appreciable numbers. In the absence of MG or M. synoviae (MS) isolation, demonstration of agglutinin, precipitin, and/or mHI antibodies in the serums of such flocks were confirmatory for MG or MS infection. The new isolate WVU 907 gave positive reactions on the SPA and AGP tests with MG antiserum. The isolate hemagglutinated chicken red blood cells (RBC) and induced low HI antibody levels (less than or equal to 1:20) when inoculated into chickens. Like MG, WVU 907 precipitin antigen was partially denatured by urea, Triton x-100, and sodium dodecyl sulfate treatment.

Agglutination Tests

Efficacy of chlortetracycline against Mycoplasma synoviae isolated in two periods.

Isolates obtained in 1954-55 were generally more pathogenic for the synovial membranes than those obtained in 1969-73. All isolates were capable of producing synovitis when inoculated into the foot pad. Chlortetracycline was effective in controlling signs of infectious synovitis at the 100-g/ton concentration. The 50-g concentration prevented mortality and reduced morbidity. All concentrations of chlortetracycline used (50, 100, or 200 g/ton of feed) reduced immune response, positive agglutination tests, and isolation of MS below that of inoculated untreated birds. Chlortetracycline at all concentrations prevented the spread of MS in contact controls. Chlortetracycline was more effective against the 1954-55 isolates than the 1969-73 isolates when measured by gross lesions, development of agglutinins, and isolation of mycoplasma. No difference in efficacy was found in mortality, weight gain, and feed efficiency.

Animals