[Properties of local velogenic strains of Newcastle disease virus in poultry].

Studies were carried out on four strains of the Newcastle disease virus, isolated in Bulgaria and referred, as typed by the routinely used methods, to the velogenic group. The strains proved to be hemagglutinin - thermostable. Two of the local virus strains (Rosa and Toutrakan) belonged to the velogenic-neurotropic pathogenic type, and two (Bregovo and Haskovo) - to the velogenic - viscerotropic pathogenic one.

[Clinical and pharmacological studies of technical tylosin phosphate from Pharmachem in poultry diseases].

Investigations on the healing anbd prophylactic effectiveness of the technical tylosine phosphate "Pharmachim" with 50 IU/mg activity (pharmazin T-50) in some bird diseases were carried out. It was established that a dose of 20 g/kg fodder pharmazin T-50 applied 2 days pre- and 3 days post chicken Mycoplasma gallisepticum infection protects the chickens completely from respiratory mycoplasmosis. In order to attain a sure healing and prophylactic effect in hen spirohetosis control 10 g/kg fodder applied 2 days or on the 24th to 48th day after Borrelia anserina invasion are completely sufficient.

[Atypical course of cholera in poultry].

Atypically developing chicken septicemia was studied at 3 farms in Bulgaria. In one of the observed centers of chicken septicemia infection no pathologic anatomical changes were evident while in the other two centers of infection serofibrinose and serofibrinose vitelline peritonitis, as well as pleurisy were present. In the bacteriological investigation carried out on 2969 samples 233 strains of chicken septicemia were isolated.

[Production and titration of a vaccine against the infectious encephalomyelitis of poultry].

A vaccine was produced against infectious encephalomyelitis of day-old chicks infected cerebrally with strain Calnek 1143. It is a brain suspension from killed birds that have shown disease symptoms, treated with penicillin and streptomycin and stored at -20 degrees C. Experiments were carried out to titrate the vaccine through determining the minimum infective dose for day-old chicks treated with 0.

[Role of the housefly in the epizootology of pseudoplague in birds].

It has been demonstrated that Musca domestica L. could harbour the Newcastle disease virus. It has been isolated from the surface of the flies body 96 hours after these had been in contact with it, and from their digestive tract--after 240 hours.