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Biomedical subjects

W C Stewart

Publications and source records attributed to W C Stewart.

At least 163 records · Page 9Linked to original sources

Stabilization of hog cholera virus by dimethyl sulfoxide.

The stability of hog cholera virus through five freeze-thaw cycles in the presence and absence of dimethyl sulfoxide was studied. In the absence of dimethyl sulfoxide the hog cholera virus titer was reduced 52% to 91% following successive freezing and thawing cycles. However, when dimethyl sulfoxide was added to the viral suspension the virus titer appeared to remain the same after the same number of freezing and thawing cycles.

Animals↗

Swine buffy coat culture: an aid to the laboratory diagnosis of hog cholera.

A 2-step technique for the isolation of hog cholera (HC) virus consisting of an initial culture on buffy coat (BC) cultures and subinoculation to a pig kidney cell line (PK-15) was described. By this technique, HC virus was confirmed in specimens from 65 herds in which the conventional cell culture isolation technique failed. The herds were located in 20 states and Puerto Rico. Specimens from 29 of the 65 herds were inoculated into specific-pathogen-free (SPF) pigs. Hog cholera virus was recovered from 27 of the test pigs. The 2 pigs from which virus was not recovered had signs of acute infection and, on necropsy, had gross lesions of HC infection.

Animals↗

Transmission of hog hog cholera virus by mosquitoes.

Mosquitoes trapped during an epizootic of hog cholera (HC) in Maryland in 1969 were prepared into 40 pools which were inoculated in pigs. Hog cholera virus was confirmed in pigs inoculated with 8 of 40 pools of mosquitoes. Generally, the pigs contracting HC developed chronic infections with persistent viremia that lasted 30 or more days. Two pigs seemed healthy when euthatized 62 and 80 days after inoculation, yet viremia of high titer was detected in each. Experimental studies were performed with 2 laboratory strains of mosquitoes, Aedes aegypti and Culex tarsalis, to determine if biological and mechanical transmission occur. Biological transmission was not confirmed, but HC virus was retained in A aegypti for 3 days. Mechanical transmission was confirmed with A aegypti in 2 of 9 experiments.

Aedes↗