Protective efficacy of vaccines against bovine dermatophytosis after double and single vaccination.

The protective efficacy of two Czech vaccines against bovine Trichophyton verrucosum infection after double vaccination of calves in prophylactic doses, with an interval of 13 days between vaccination and revaccination, was very good. When these preparations were applied in a double dose only once, less protective effect was produced. The use of 0.5% aluminium hydroxide to dilute the vaccines had no influence on the effect of single vaccination.

[Annual testing of immunity in foxes after oral rabies immunization]. / Overení rocní imunity u lisek po orální imunizaci proti vztekline.

Ten young foxes were orally immunized with a "Rabies vaccine for oral immunization of foxes--LYSVULPEN por. a.u.v.," batch 69 10 93, commercially manufactured by the company Bioveta, s.r.o. at Ivanovice in Haná. The vaccine contained 1.8 x 10 of rabies vaccination virus, strain SAD-Bern, in a vaccination dose. Three foxes were used as control animals without vaccination. Blood samples were taken before the beginning of the experiment in all test foxes, and then in three-month intervals. The last blood samples were taken just before the beginning of a challenge experiment and two months after challenge in the foxes that survived. A challenge test was done in all foxes (vaccinated and nonvaccinated ones) a year after single oral immunization against rabies. Challenge virus was prepared from the salivary gland of a naturally infected fox living in the territory of the Czech Republic. Street virus was applied to each fox i.m. to a great depth to both masticatory muscles (musculus masseter) at a total dose of 10,000 MICLD50. The experimental animals were 60 days under observation. Tab. I shows the titers of virus-neutralizing rabies antibodies after oral immunization against rabies in all experimental foxes. Except fox no. 8, the formation of specific virus-neutralizing rabies antibodies was recorded in all animals after they had eaten vaccination baits. The antibodies were detected throughout the whole year of observation. Tab. II shows the results of challenge test. Out of the nine vaccinated foxes (fox no. 9 died before infection) only fox no. 8 died from rabies, the other treated foxes were protected from rabies (89% rate of protection). Tab. III presents the results of laboratory examination. Tetracycline was demonstrated in all treated foxes (a vaccination proof). Death due to rabies was demonstrated in control animals without vaccination and in fox no. 8. The results achieved in the Czech Republic for oral immunization of foxes against rabies with the vaccination strain SAD-Bern document very good efficacy of the vaccine manufactured by the company Bioveta, s.r.o., in Ivanovice in Haná since 1992. Oral immunization largely improved the infection situation in the Czech Republic. A total of 1,501 cases of rabies infection were recorded at the start of vaccination in 1989 while it was only 221 cases in 1994 (a decrease in then number of foci by 85%).

Common and different antigenic properties of the rabies virus glycoprotein of strains SAD-Vnukovo and Pitman-Moore.

Two fixed rabies virus strains, SAD-Vnukovo and Pitman-Moore (PM) were used as combined immunogens for the generation of hybridomas secreting specific monoclonal antibodies (MoAbs). The obtained hybridomas were primarily screened by an ELISA for production of MoAbs to antigen of SAD-Vnukovo strain. Six positive clones were established. A panel of MoAbs has been characterized according to reactivity in immunofluorescence, immunoblot, ELISA and neutralization tests. All MoAbs were positive in immunofluorescence when cells infected with the SAD-Vnukovo strain were used. By immunoblot, four MoAbs showed specificity for the viral glycoprotein of both SAD-Vnukovo and PM rabies strains. This pattern of reactivity indicated the existence of shared conformation-independent epitopes located on the related antigens. However, in ELISA, the tested MoAbs did not recognize viral glycoproteins of the PM strain. This indicates, that the different strain-specific conformations of the native glycoprotein determine the accessibility of the common linear determinants for respective antibodies. Only one antibody, with conformation-dependent glycoprotein specificity, was capable to neutralize the CVS strain of rabies virus.

Conformation-dependent accessibility of the linear epitopes located on the rabies virus glycoprotein.

Seven monoclonal antibodies (MAbs) were derived from mice immunized with the rabies virus glycoprotein of the Pitman-Moore (PM) strain. These antibodies recognized at least five partially overlapping sites located in one immunodominant region. A panel of MAbs was then used to characterize antigenic relationship between PM strain and SAD-Vnukovo strain of these rabies viruses. In immunoblot, all tested antibodies bound to the glycoprotein of both rabies strains, indicating shared antigenic determinants located on the corresponding immunodominant regions. The pattern of reactivity in immunoblot suggested the specificity of antibodies against linear epitopes. However, the supposed close antigenic relation between PM and SAD-Vnukovo strains (evidenced by immunoblot) was not fully confirmed by immunoenzymatic assay. Data provided by ELISA demonstrated two distinct patterns of MAbs reactivity with both antigens. Four antibodies showed specificity for PM strain glycoprotein only, while three MAbs bound with both PM and SAD-Vnukovo strain antigens. We supposed the strain-specific conformation of the native glycoprotein to be responsible for selective access of single MAbs to the respective common linear epitopes.

[The minimal effective dose of vaccine against trichophytosis in heifers]. / Minimální efektivní dávky vakcíny proti trichofytóze skotu.

Calves at the age of one month were vaccinated with a lyophilized vaccine against bovine trichophytosis, or with an avirulent vaccine against bovine trichophytosis (mfd by Bioveta, Ivanovice in Haná). Prophylactic doses of the vaccines (15 mil. CFU of production strain Trichophyton verrucosum per calf) were used for immunization, and doses 10 times, 100 times and 1000 times lower. The calves were revaccinated with the same doses in 12 days after the first vaccination. Twenty-eight days later since revaccination, the vaccinated calves and a group of control nonvaccinated calves was challenged epicutaneously with a virulent strain of T. verrucosum. The protectiveness of both vaccines implanted at doses of 2 x 15 mil. and 2 x 1.5 mil. CFU per test animal was very good. No dermal lesion were observed in the challenged calves of these groups, or if any, they were not clear and could be observed for a short time. If the vaccines were used diluted at a ratio 10(-2) (150 thousand CFU of production strain), trichophytic lesions persisting for the whole period of observation were found in four of the seven calves vaccinated with a lyophilized vaccine against bovine trichophytosis and in two of the eight calves implanted an avirulent vaccine after challenge. Mycotic lesions were formed after challenge in all test animals in the groups vaccinated with doses of 2 x 15 thousand CFU of production strain per calf. The extent of these lesions was practically the same as in all nonvaccinated controls--on the surface of infected skin the hair was shed and scales and crusts were formed. A challenge strain of T. verrucosum was cultivated from these lesions.

Immunity in cattle vaccinated against ringworm.

Protective properties of a live, freeze-dried vaccine against ringworm, produced by Bioveta, Ivanovice na Hané, Czechoslovakia, were tested in a group of 422 calves. Vaccinated and control calves were challenged by epicutaneous inoculation of a virulent culture of Trichophyton verrucosum. Between 4.4 and 9.5% of calves challenged between days 14 and 25 after revaccination showed only mild clinical signs of ringworm and 99-100% were fully protected from day 28, the immunity persisting for at least one year. All control calves showed signs of ringworm after challenge. In most cases, extensive mycotic lesions, also penetrating into deep skin layers, were observed. Protective properties of the Czechoslovak vaccine and a USSR vaccine were high and comparable.

[Experimental trichophytosis in calves caused by cultures of Trichophyton verrucosum and Trichophyton equinum]. / Experimentální trichofytóza telat vyvolaná kulturami Trichophyton verrucosum a Trichophyton equinum.

Tests were performed on 130 one-month-old calves. In 16 animals, treatment with a suspension of Trichophyton verrucosum culture at the dosage of 5 mil. conidia for an area of 10 x 10 of the clipped skin caused clinical trichophytic changes. The length of the incubation time was shorter in the calves scarified before inoculation of the infecting culture (10 to 13 days), as compared with the group of calves without scarification of the skin (11 to 19 days). Only 3 in 6 calves, infected by the same dose into non clipped skin, did contract trichophytosis, manifesting themselves as separate mycotic deposits, which appeared 26 to 35 days after inoculation. Trichophytic changes lasted longest in the group with scarification of the infected area. The ID50 in T. verrucosum and T. equinum cultures was about 1500 conidia per one calf in the case of the method of infecting into clipped scarified skin (area 100 sq cm). A 10 times lower dose (150 conidia per one calf) of the T. verrucosum suspension did not induce visible mycotic changes, but the T. equinum inoculation produced infection in one of 10 calves.

[Evaluation of the the effectiveness of a newly developed tissue-inactivated vaccine against rabies using the NIH test]. / Hodnocení úcinnosti vyvíjené vakcíny proti vztekline tkánové inaktivované NIH testem.

NIH test was used to verify 12 operation batches of the newly developed inactivated tissue vaccine against rabies. The number of international units per 1 cm3 of vaccine was determined by the volumetric method. The number of international units (I.U.) per 1 cm3 of the newly developed vaccines ranged from 1.08 I.U. to 2.59 I.U. per cm3. The average value of all the 12 batches tested is 1.52 I.U. per cm3. The average value of international units in the vaccination dose for dogs is 4.57. All the tested operation batches of the newly developed vaccines met the activity standard recommended by the World Health Organization for veterinary vaccines of this type.

[Testing for immunogenic and protective properties of vaccine against tissue-inactivated rabies]. / Overování imunogenních a protekcních schopností vakcíny proti vztekline tkánové inaktivované.

The immunogenic and protective potency was tested of vaccine against inactivated tissue rabies developed from the Vnukovo-32 strain, and produced in the Bioveta state corporation at Ivanovice in Haná. In 21 days after an i. m. application of 3 cm3 of vaccine, the average titre of virus-neutralizing antibodies was found to be 1:47. In this period the animals were revaccinated in the same way. The average titre of virus-neutralizing antibodies was 1:99 three months after revaccination, 1:57 in six months and 1:24 in nine months. In this period a challenge test was performed in a dog using the dose of 10(5) MICLD50 of street rabies virus. This dose was implanted i. m. into masticatory muscles. Another dog was infected experimentally 18 months after immunization. The experiment has proved the good immunogenic potency of vaccine against inactivated tissue rabies and its ability to induce the protection of vaccinated dogs from the strees infection with street rabies virus. The control rabies vaccine of foreign make RABISIN was tested in a similar way.

[The development of immunity after vaccination of cattle against trichophytosis]. / Vznik imunity po vakcinaci skotu proti trichofytóze.

Trials were conducted with 262 one-month-old calves. Good immunity was found to have developed within the period of 21 to 28 days after the administration of the Czechoslovak live vaccine against bovine trichophytosis. After epicutaneous inoculation of a highly virulent culture of Trichophyton verrucosum, performed 28 and 35 days after re-vaccination, no clinical form of trichophytosis was observed to rise in the calves. The same doses of challenge inoculum induced profound trichophytic changes. In the groups of calves artificially infected on the day of re-vaccination and seven days after re-vaccination, the proportions of experimental animals that fell ill were 88.2% and 44.4%, respectively; in the majority of cases, the course of the disease was not so serious as in the controls. Calves challenged 11 to 21 days after the second administration of the vaccines were mostly resistant to experimental infection: slight changes occurred in 15.4 to 7.0% of the tested animals.

[Testing the protective effectiveness of avirulent vaccines against trichophytosis in cattle]. / Overování protekcních schopností avirulentní vakcíny proti trichofytóze skotu.

The protective action of live avirulent vaccine against bovine trichophytosis, produced by the Bioveta National Corporation at Ivanovice na Hané, was very good and fully comparable with the earlier vaccine produced from the virulent live culture of Trichophyton verrucosum. Experimental challenge with a massive dose of a virulent strain of T. verrucosum produced only minor surface dermal changes in the calves vaccinated with these vaccines, but these changes spontaneously disappeared in a short time. In the control non-vaccinated calves, large and deep lesions were induced by the challenge, spreading to the neighbouring tissues. Compared with both live biopreparations, the protective effect of inactivated vaccine prepared by the irradiation of virulent vaccine with Co60 was much lower.

[Disinfection for dermatomycoses in veterinary practice]. / Dezinfekce pri dermatomykózách ve veterinární praxi.

Sporulating cultures of two strains of Trichophyton equinum, two strains of Trich. mentagrophytes and one strain of Microsporum canis were tested by a simple dipping technique for their sensitivity to ten currently used disinfectants. Antifungal effects on all cultures of dermatophytes were observed already after one-minute treatment with 0.5%-4% peracetic acid, 4% formaldehyde solution and concentrated solution of Lastanox super. The above strains were inactivated after five-minute treatment with 1% and 2% formaldehyde solution, 20% Iodonal B solution and Ajatin solution with 10% active substance. Fungistatic effects of various intensity were observed in the other disinfectants.