Glutaraldehyde inactivation of exotic animal viruses in swine heart tissue.

Glutaraldehyde, 0.2%, in a 1:100 (wt/vol) ratio, inactivated four animal viruses (foot-and-mouth disease, swine vesicular disease, African swine fever, hog cholera) in swine heart tissues during 11-day exposures at 22 to 26 degrees C.

Inactivation of Milkborne Foot-and-Mouth Disease Virus at Ultra-High Temperatures 1.

Milk from cows with foot-and-mouth disease containing 103-7 to 106-4 plaque-forming units of virus/ml was exposed to several ultra-high temperature treatments for 2-5 sec. Results indicated that the virus in such milk could be reliably inactivated when held at 148 C for 3 sec or longer.

Persistence of Foot-and-Mouth Disease Virus in Dried Casein 1.

Dried casein produced from pasteurized milk of dairy cows infected with foot-and-mouth disease (FMD) virus retained infectivity for cattle in one of seven tests for 42 days of storage at 25 C. Thus, infections FMD virus can persist after pasteurization of the milk at 72 C for 15 sec., acid precipitation and washing of casein, followed by drying of the casein in a hot air flow and conversion to sodium caseinate.

Interferon inducers and foot-and-mouth disease vaccines: influence of two synthetic polynucleotides on antibody response and immunity in guinea pigs and swine.

Polyriboadenylic-polybouridylic acid enhanced the immunological response of guinea pigs to aqueous foot-and-mouth disease virus vaccine. Polyriboninosinic-polyribocytidylic acid enhanced the early antibody production of swine to oil emulsified foot-and-mouth disease virus vaccine. Polyriboninosinic-polyribocytidylic acid alone did not stimulate resistance to foot-and-mouth disease in swine.

Survival of Foot-and-Mouth Disease Virus in Casein and Sodium Caseinate Produced from the Milk of Infected Cows 1.

Milk-borne transmission of foot-and-mouth disease virus (FMDV) was implied during the 1967-1968 epizootic in England. Consequently, experiments were designed to study survival of FMDV in milk and dairy products. As part of these studies, eight batches of casein were prepared from milk collected at various times after infection of cows with FMDV. Raw skimmilk was used in two batches and pasteurized (72 C, 15 sec), skimmilk was used in six. Casein was obtained by acidulation of skimmilk to pH 4.6 with HCI. Each batch was tested for FMDV infectivity either as casein or sodium caseinate in cell cultures and by inoculation of cattle. Samples assayed in cell cultures did not show evidence of infectious FMDV. However, cattle inoculated with these samples became infected with FMDV in one of two trials in which the casein was prepared from raw skimmilk and in three of six trials with skimmilk which was pasteurized. Samples from one of two dried casein batches infected test cattle. Samples from four of six batches of casein prepared from uninfected cows milk to which FMDV was added before pasteurization also infected cattle.

Inactivation of foot-and-mouth disease virus with ethylenimine.

Foot-and-mouth disease virus (FMDV) was inactivated by ethylenimine (EI) at three concentrations and two temperatures. Comparison of inactivation kinetics and the antigenic and immunogenic potency of EI and N-acetylethylenimine (AEI)-inactivated FMDV indicates that EI has nearly optimal characteristics as an inactivant for FMDV vaccine preparation. Although AEI-inactivated FMDV has proved to be a potent specific immunogen, an equivalent percentage of EI inactivated FMDV at substantially faster rates and produced an equally potent immunogen. In addition, EI inactivated FMDV at rates that were essentially linear throughout the loss of nearly all measurable infectivity.

The purification and concentration of hog cholera virus.

Partial purification of hog cholera virus (HCV) using a simple batch-type chromatographic procedure with magnetic ferric oxide (MFO) is described. Infectious HCV was adsorbed from isotonic solutions to MFO and was eluted under conditions of low ionic strength and high pH. Aqueous solutions of 0.01 M sodium cyanide or 0.0003 M ammonium hydroxide effectively dissociated MFO-HCV complexes. The data indicate that 50 to 100% of the original HCV infectivity was recovered concomitant with a 90 to 95% reduction of extraneous organic nitrogen.MFO-purified HCV was concentrated by density gradient type centrifugations in buffered solutions of cesium chloride and sucrose. Prolonged isodensity centrifugations of concentrated MFO-purified HCV indicated a buoyant density of 1.14 to 1.15 gm/ml for the strain of virus used.

The purification and concentration of hog cholear virus with electron micrographs (a preliminary note).

Cell-cultured hog cholera virus was partially purified by chromatography on pulverized magnetic ferric oxide. Infectivity yields of 50 to 100% were obtained with a 90 to 95% reduction in extraneous organic nitrogen. Concentration and further purification of infectious virus were achieved by rate-zonal and isopycnic ultra-centrifugations in buffered cesium chloride. Density determinations obtained from the isopycnic experiments indicate a buoyant density of 1.14-1.15 gm/ml for the strain of virus used. Electron microscopy of negatively stained samples of concentrated infective virus from one isopycnic experiment revealed 40- to 40-mmicro virus-like particles and a large number of 12- to 15 mmicro entities. The 40- to 50-mmicro particles were surrounded by a poorly defined, asymmetrically arranged sac-like membrane or appendage. It is suggested that the images of the 40- to 50-mmicro particles represent the infective virion of hog cholera virus.