Day-old vaccination with live-in-oil vaccines: Newcastle disease (ND) and infectious bursal disease (IBD) in chicks and ND in turkey poults.

One-day-old broiler chicks were vaccinated with live Newcastle disease (ND) vaccine incorporated in oil alone or in killed-in-oil ND vaccine. Incorporation of live vaccine in oil emulsions was carried out just prior to vaccination. Live-in-oil ND vaccine containing 106.0 median embryo lethal doses (ELD50/dose induced the same protection following challenge and the same level of antibody at 42 days post-vaccination as did commercial killed-in-oil ND vaccine containing about 250 times as much antigen (108.4 ELD50/dose). Incorporation of live ND vaccine in killed-in-oil vaccine contributed markedly to protection rates and antibody levels, as compared to those obtained following vaccination with killed-in-oil vaccine only. One-day-old turkey poults also showed the advantage of incorporation of live ND vaccine in killed-in-oil vaccine when challenged 3 months post-vaccination. One-day-old broiler chicks, vaccinated with live ND and infectious bursal disease vaccine (IBD) incorporated in killed-in-oil combined ND + IBD vaccine, showed better protection against challenge with IBDV and higher antibody levels to NDV as compared to vaccination with killed-in-oil vaccine alone.

Vaccination of turkeys in the wattles (dewlap) with turkey meningo-encephalitis live vaccine and Pasteurella multocida killed-in-oil vaccine.

Vaccination of turkeys via the wattle has been introduced as a novel route of vaccination using attenuated live viral turkey meningo-encephalitis (TME) and killed-in-oil bacterial (Pasteurella multocida) vaccines. The efficacy of the immunization was evaluated by the haemagglutination-inhibition test for TME and by challenge for TME and P. multocida. Immunization via the wattle route was comparable or better as compared with the conventional routes, intramuscular and subcutaneous, for P. multocida and TME, respectively. These results were obtained by wattle vaccination administered either by injection, punching with a needle as used for fowl pox vaccination or by topical application. The advantages of wattle vaccination are: no local untoward reactions (P. multocida), which might frequently occur in the muscles following improper subcutaneous mass vaccination, less time and labour consuming, and less stress for the turkeys. It is suggested to test the wattle route of vaccination with other viral and bacterial vaccines in turkeys and other avian species.

Host factors affecting the homologous and heterologous immune response of cattle to FMDV: genetic background, age, virus strains and route of administration.

Sixty bulls were tested for antibodies to the heterologous serotype C1 of FMDV following repeatable vaccinations with a commercial trivalent vaccine (O1, A22, Asia1). Six (10%) bulls were found to possess rather high levels of heterologous neutralizing antibodies which showed accumulative trend with age. Two high positive and two negative bulls for the heterologous serotype C1 were selected for progeny test involving ten daughters of each bull. The four bulls, either positive or negative for the heterologous serotype C1, showed significant phenotypic correlation between their heterologous and homologous titers (O1, A22, Asia1). This correlation between heterologous and homologous antibody titers was not found in the daughters of these bulls. However, two of ten daughters of one positive bull, to C1 showed individual high titers (> or = 1.5). The intradermal (ID) as compared to subcutaneous (SC) route of administration resulted in higher rate of responders to both heterologous serotypes C1 and SAT1. The heterologous immune response to FMDV in Israeli-Friesian cattle was found to be related to the age of the host, multiplicity of vaccinations, route of vaccination, kind and numbers of the antigens used in the vaccine. The homologous immune response is also controlled by genetic factors.

Homologous and heterologous antibody response of cattle and sheep after vaccination with foot and mouth disease and influenza viruses.

Homologous and heterologous antibody response to FMD and influenza vaccines was studied in 37 calves and 45 lambs at the age of 2 months. The FMD and influenza monovalent killed vaccines were administered simultaneously twice. Another group of 18 calves was vaccinated twice, first at the age of 2 months and second at the age of 6 months, with trivalent FMD vaccine. The antibody titers were measured by ELISA and HI after second vaccination, for FMDV and influenza, respectively. The conclusions of this study are summarized as follows. Individuals, lambs and calves, that cross-respond to one heterologous serotype are liable to respond to another heterologous serotype of the same virus. Individuals, lambs and calves, showing double cross-reactivity to one virus (FMDV), are highly liable to show double cross-reactivity to entirely another virus (Influenza). Multivalent vaccines of FMDV are expected to elevate the antibody titers for at least one heterologous serotype (not included in the vaccine) and to detect antibodies for an additional heterologous serotype, not detected otherwise following monovalent vaccination. These results indicate the important role of the host in the spectrum of the specific immune response.

Enhanced antibody response in cattle against Leptospira hardjo by intradermal vaccination.

A commercial killed Leptospira hardjo vaccine (with adjuvant) and non-adjuvanted preparation of the same vaccine were used in comparison of the effectiveness of the intradermal (i.d.) and subcutaneous (s.c.) routes for these vaccines. The tests were conducted in 50 females aged 6-14 months. After the first vaccination, both types of vaccine elicited a very poor antibody response by both routes of vaccination. However, after booster vaccination, the commercial vaccine (with adjuvant) elicited a remarkable immune response which was twice as high by i.d. compared with s.c. vaccination. No local or general adverse reactions were observed after i.d. vaccination with the adjuvanted commercial vaccine (potassium aluminium sulphate).

Comparison of dimethyl dioctadecyl ammonium bromide, Freund's complete adjuvant and mineral oil for induction of humoral antibodies, cellular immunity and resistance to Newcastle disease virus in chickens.

Dimethyl dioctadecyl ammonium bromide (DDA), a lipophilic quaternary amine, was evaluated in adult chickens for potentiation of immunological responses to subcutaneously administered inactivated Newcastle disease virus (NDV) vaccines. DDA enhanced humoral and cell-mediated immune (CMI) responses to levels which were significantly higher than those induced by the vaccine alone The haemagglutination inhibition antibody titers induced by DDA were slightly lower than those induced by mineral oil although neutralizing antibody titers seemed to be higher. DDA induced strong CMI (DTH and lymphocyte proliferation) responses, more than those induced by Freund's complete adjuvant and mineral oil. Both DDA and mineral oil induced comparable high levels of protection to challenge doses of 200,000 LD50 per chicken. No toxic effects or local tissue damage were observed in any of the inoculated chickens.

Vaccination of chickens with live fowl pox (FP) vaccine in oil.

Live fowl pox (FP) vaccine was adjuvanted in oil just prior to the subcutaneous (SC) vaccination of one day old chicks and adult chickens. The birds were challenged by the wing web (WW) method and absence of "takes" were considered as protection. On 21 day post challenge, 90%-100% of the chicks or chickens were protected while on day 9 post challenge 60% were protected. Full protection of the live-in-oil adjuvanted vaccine is probably somewhat delayed as compared to protection endowed by the liquid vaccine. Incorporation of live FP vaccine in two different kinds of commercial Newcastle disease (ND) killed vaccine in oil, was shown to endow full protection following SC administration.

Immunization of chickens with live Newcastle disease vaccine adjuvanted with oil.

Chickens of various ages and breeds were vaccinated subcutaneously with Newcastle disease live-in-oil vaccines. These vaccines were prepared immediately prior to the vaccination by mixing the lyophilized live vaccine with the oil adjuvant, which was kept at room temperature. The live-in-oil vaccines were shown to be 30-50 times more effective in efficacy tests than either the same vaccines reconstituted in water or killed-in-oil vaccines. In addition to its biological advantage, the method of preparation of live-in-oil vaccine saves the expensive space of cold storage and shipment necessary for conventional killed-in-oil vaccines.

Differences in protection between heavy and light breeds of chickens following vaccination with Newcastle disease vaccines-a survey of data, 1971 to 1990.

Data obtained over 20 years of Newcastle disease vaccine testing were statistically analyzed. The protection afforded heavy and light breeds of chickens was compared following challenge (efficacy) after vaccination with live and inactivated vaccines produced from different virus strains. Standard challenge virus was used throughout the period. The data show that the heavy breeds were significantly inferior in their protectability when compared with the light breeds. This inferiority was shown after vaccination with all types of vaccines. It is suggested that heavy and light breeds of chickens differ genetically in their acquired resistance to Newcastle disease virus, although difference in susceptibility to the virus as a pathogen cannot be ruled out entirely.

Mouse footpad Langerhans cells as an indicator for safety of foot and mouth disease virus vaccines.

The effect of various vaccines against foot and mouth disease virus (FMDV) was tested on Langerhans cell density in the footpad epidermis of mice. Injection of monovalent, bivalent and trivalent FMDV vaccines caused a reduction in Langerhans cell density in the murine skin, which was more marked at the center of the footpad, the site of injection, than at the periphery. Testing of the various components of the vaccine showed that saponin caused a marked reduction in Langerhans cells while injection of aluminium hydroxide had a lesser effect and the virus alone had no effect on these cells. Thus Langerhans cell density could serve as an efficient marker to test the safety of vaccines to FMDV since the integrity of Langerhans cells, which are the antigen-presenting cells in the skin epidermis, is needed for an effective immune response to the vaccine.

Selection for early responsiveness of chicks to Escherichia coli and Newcastle disease virus.

A broiler chicken population was divergently selected for high or low early immune responses to Escherichia coli and to Newcastle disease virus (NDV) vaccines. Four selection cycles were performed in one replicate, and a single cycle in a second replicate. Selection was based on sire-family averages of a titer index (TI) calculated as the mean titer of antibodies produced by offspring vaccinated with either E. coli or NDV at 18 or 10 days of age, respectively. After the first selection cycle, TI of the early-high (EH) line were 22 and 38% greater than those of the early-low (EL) line in Replicates A and B, respectively. After four selection cycles, the average immune response to E. coli and NDV of Line EH exceeded that of Line EL by 68%. Viability was greater in the EH than in the EL line. Realized family heritabilities were .72 and .67 in Replicates A and B, respectively and the levels of response to the two antigens were not genetically correlated. The immune response of the EH line developed earlier than that in the EL line as shown by fewer nonresponders against E. coli and the higher response of this line against the two antigens at young ages. Mortality after challenge at 18 days of age and general mortality from hatching to 20 wk of age was lower in Line EH than in Line EL. Body weights at 7 wk were higher in EH than EL chicks.

Enzyme-linked immunosorbent assay for detection of antibodies to Rift Valley fever virus in ovine and bovine sera.

An enzyme-linked immunosorbent assay (ELISA) was developed for the rapid detection of antibodies to Rift Valley fever virus (RVFV) in ovine and bovine sera. Conditions to reduce nonspecific reactions were optimized. The ELISA results correlated with those of a plaque-reduction neutralization test, revealing 100% specificity and 90.7% sensitivity. In sera from sheep and cattle inoculated against RVFV, the hemagglutination-inhibition test in combination with the ELISA provided a better indication of response to killed RVFV vaccine than did either test alone.

Prevention of strabismic amblyopia of early onset with special reference to the optimal age for screening.

Of 78 consecutive cases with constant unilateral esotropia diagnosed during screening and treated from the ages of seven months to three years, 82% ended up with visual acuity of 6/12 or better toward end of active treatment at the age of six to eight years. Of the cases with visual acuity of 6/12 or better at the end of treatment, 59% retained their vision when re-examined four to ten years later. The most important single parameter for the achievement of normal visual acuity was age of onset of treatment below two years and for long-term stability of the result this age dropped to 18 months. Initial large angles of esotropia had better prognosis probably because they were associated with an earlier onset of treatment. Poor prognosis was associated with faulty or no fixation of the esotropic eye when first diagnosed, with the failure to achieve alternation and with marked ansiometry. The optimal age for screening for strabismic amblyopia was suggested to be 12-18 months.

The ontogeny of the humoral immune response to E. coli vaccine and to sheep red blood cells in young chicks.

The ontogeny of the humoral immune response to sheep red blood cells (SRBC), a non-infective antigen, and to killed Escherichia coli (E. coli), a disease-related antigen, was compared in young chicks of three poultry populations: a White Leghorn layer strain and two strains of White Rock broiler breeders. SRBC were injected intravenously into randomly selected groups of chicks every 3 days from hatch until 42 days. In separate groups of chicks, E. coli (1 x 10(8) heat-inactivated organisms) were injected intravenously over the same age range. A clear difference was found in the response pattern to the two antigens with age. The response to SRBC developed rapidly: at 6 days 'of age most chicks showed measurable antibody titres. The response to E. coli developed more slowly: at 6 days of age most of the chicks in the three strains tested did not show measurable antibody titres. The age response pattern of the two White Rock strains tended to be similar to one another and to differ from the response of the White Leghorn strain. Considerable variation in antibody titre was found within each group of chicks. These results indicate that differences are present in the rate of development of the immune response to different antigens and suggest that genetic differences in the rate of development of the immune response to a given antigen may be present both between and within poultry populations. Thus, increasing the rate of development of the immune response in poultry populations may be a feasible breeding objective.

Outcome of treatment of marked ametropia without strabismus following screening and diagnosis before the age of three.

Following early treatment of 39 consecutive cases with marked ametropia without strabismus, diagnosed by screening at the age of one to two and a half years, residual amblyopia was found in 20 (51%), including six (15%) with bilateral amblyopia, but with relatively good visual acuity in at least one eye. Anisometropia showed the highest rate of residual amblyopia. The main changes in refraction that occurred from the age of screening to the age of seven years was myopisation, especially in hypermetropic eyes without amblyopia. Heterotropia, always intermittent, developed in six of the 39 cases. Full stereopsis could be found in eight cases only, all without amblyopia. The majority, whether amblyopic or not, had partial binocular functions but four cases, all amblyopic, had none.

Natural haemagglutinins and immune responsiveness in young chicks.

Titres of natural haemagglutinins to sheep erythrocytes and of experimentally induced antibodies to Newcastle disease virus (NDV), bovine serum albumin (BSA) and human gammaglobulin (HgG) were determined in White Rock broiler chicks immunised at 28 days of age. There was no relationship between levels of natural haemagglutinins and induced antibody levels or between titres of antibody to NDV and titres of antibody to BSA or HgG. A highly significant correlation (r=0.37) was found between titres of antibody to BSA and to HgG.

A serological survey of Rift Valley fever antibodies in the northern Sinai.

In the aftermath of an extensive Egyptian Rift Valley fever (RVF) epidemic during 1977-78, RVF activity in the adjacent Sinai peninsula has been inferred from the presence of haemagglutination-inhibition (HI) antibodies in sera from indigenous humans and rodents. We attempted to confirm these findings by HI testing of sera from Israeli soldiers serving in the region of the El Arish Wadi system in the Sinai, and from indigenous rodents. Six of 199 human sera (3.0%) and two of 88 rodent sera (2.3%) were positive, but none reacted in the more specific plaque-reduction neutralization test. We conclude that there is no definitive serological evidence for RVF activity in the Sinai and that sera reacting in the HI test must be confirmed by a more specific serological procedure.