A composite vaccine for the immunization of dogs and foxes against distemper and hepatitis contagiosa canis

摘要

A composite vaccine for the immunization of dogs or foxes against distemper and Hepatitis contagiosa canis (H.C.C.) is prepared by mixing an aqueous suspension of an apathogenic distemper virus obtained from developing thick embryos with an aqueous suspension of H.C.C. virus which has been isolated from the liver and/or spleen of dogs or from tissue cultures and has been inactivated with an excess of formaldehyde, the excess of formaldehyde being chemically bound after inactivation of the virus by adding 1 1/2 to 2 times the stoichiometric quantity of an acid salt of sulphurous acid especially sodium bisulphite. The vaccine contains (a) 50% of the distemper component consisting of 50% chlorio-allantoic material containing distemper virus, 40% beef nutrient broth of pH 7.6 and 10% aqueous glucose and (b) 50% H.C.C. component preferably consisting of 75% aqueous suspension of inactivated H.C.C. virus and 25% aqueous aluminium hydroxide suspension. The chlorio-allantoic membranes of chick eggs are inoculated with a 4% aqueous suspension of a modified distemper virus in aqueous phosphate buffer of pH 7.6, incubated 5 days at 37 DEG C., the chlorio-allantoic membranes removed, homogenized in ice and diluted with the above beef tea and glucose. H.C.C. containing liver and spleen of dogs is homogenized in ice, suspended in water and treated with 35% formaldehyde for one hour. After storage for one week at 4 DEG C., the supernatant liquid is mixed with 2% aqueous sodium bisulphite and excess free formaldehyde is fixed with sodium bisulphite. H.C.C. is also obtained from a tissue culture of dog kidney cells. The mixed vaccine is lyophilised and may be used in admixture with pharmaceutical diluents.