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W H Allan

Publications and source records attributed to W H Allan.

At least 19 recordsLinked to original sources
PubMed1984

Comparison of the immunogenicity of Newcastle disease virus strains V4, Hitchner B1 and La Sota in chickens. 2. Tests in chickens with maternal antibody to the virus.

The immunogenicity of three Newcastle disease virus (NDV) strains--V4, Hitchner B1 and La Sota, was assessed in chickens that had varying levels of maternal antibody to the virus. Chickens were immunised at different ages by the eye drop and aerosol methods. The immune response of chickens to similar doses of the strains was affected by the presence of maternal antibody. Both the level of maternal antibody and the strain of virus used affected the result. Strain La Sota was least affected as it took higher levels of maternal antibody to depress response to it than were required to have a similar effect on Hitchner B1 and V4. Strain V4 was the strain most affected by circulating maternal antibody. The results demonstrated that strain V4 was less immunogenic than Hitchner B1 and La Sota when used in chickens with maternal antibody to NDV.

Animals↗
PubMed1984

Duration of excretion of virulent Newcastle disease virus following challenge of chickens with different titres of serum antibody to the virus.

Virulent Newcastle disease virus (NDV) was isolated from susceptible and immune chickens following intra-ocular challenge with the Essex '70 strain. Challenge virus was isolated from the trachea and cloaca of susceptible birds until they died 7 to 9 days after challenge. This virus was isolated from immunised chickens for up to 14 days after challenge. The duration of excretion was influenced by the prechallenge serum antibody titre to NDV. It persisted longest in chickens with titres of 2(3) to 2(7) and decreased in length and frequency from chickens with titres in the range 2(8) to 2(12). Chickens with pre-challenge titres of 2(3) to 2(5) developed 2- to 3- fold increases in post-challenge titres, whereas those with higher pre-challenge titres had smaller proportional increases in titre. Excretion of virulent virus from immunised birds should be considered in the development of Newcastle disease control programs.

Animals↗
PubMed1984

Comparison of the residual virulence of Newcastle disease vaccine strains V4, Hitchner B1 and La Sota.

The clinical response of 7-day-old chickens to Newcastle disease vaccine strains V4, B1 and La Sota administered by the aerosol method was used to study the residual virulence of the strains. Parameters used to assess the severity of the clinical response were the number of sneezes recorded and the weight gain of chickens in the 10 day test period. The demeanour of the chickens was also observed. Strain V4 was less pathogenic for chickens than strain B1 which was less virulent than strain La Sota. Statistically significant differences were recorded in weight gain and the number of sneezes detected in each group. An unexpected mild respiratory disease recorded in chickens dosed with strain V4 may have been associated with administration of virus as a fine particle aerosol.

Animals↗
PubMed1982

Identification of paramyxoviruses isolated from birds dying in quarantine in Great Britain during 1980 to 1981.

During 1980 to 1981 a total of 61 paramyxoviruses were isolated from imported captive birds dying during the quarantine period required under the Importation of Captive Birds Order 1976. These viruses were identified as avian paramyxovirus serotype PMV-1, 13 isolates (eight Newcastle disease viruses of high virulence, five of low virulence); PMV-2, 38 isolates; PMV-3, nine isolates and one isolate provisionally typed as PMV-7.

Animals↗
PubMed1979

Characterisation of influenza viruses isolated from turkeys in Great Britain during 1963--1977.

Seven influenza viruses isolated from turkeys in Great Britain since 1963 were typed by haemagglutination inhibition and neuraminidase inhibition tests as: A/turkey/England/63 (Hav 1 Nav 3), A/turkey/England/66 (Hav 6 N2), A/turkey/England/69 (Hav 7 N2), A/turkey/Scotland/70 (Hav ? Neq 1), A/turkey/England/N28/73 (Hav 5 N2), A/turkey/England/110/77 (Hav 6 N2), A/turkey/England/647/77 /Hav 1 Neq 1). A/turkey/Scotland/70 failed to show a haemagglutinin relationship with any of the representative strains and may possess a hitherto unreported haemagglutinin subtype. Intravenous pathogenicity tests in six-week-old birds showed only A/turkey/England/63 to have high virulence for turkeys and chickens. A/turkey/England/69 produced some signs of disease in chickens and, to a lesser extent, turkeys but all other isolates were avirulent.

Animals↗
PubMed1978

The pathogenicity of four avian influenza viruses for fowls, turkeys and ducks.

Groups of 10 two-week-old chicks, turkey poults and ducklings were each infected by the intranasal route with one of four avian influenza viruses: a/fowl/Germany/34 (Hav 1N))--Rostock, A/FPV/Dutch/27 (Hav 1 Neq 1)--Dutch, A/fowl/Victoria/75 (Hav 1 Neq 1)--Australian, and A/parrot/Ulster/73 (Hav 1 N1)--Ulster. Eight hours after infection 10 birds of the same age and species were placed in contact with each group and allowed to mix. The clinical signs of disease and onset of sickness and death were recorded. Ulster virus was completely avirulent for all birds. Rostock, Dutch and Australian viruses were virulent for fowls and turkeys causing death in all birds with the exception of 3/10 in contact fowls from the Rostock virus group and 2/10 in contact fowls from the Australian virus group. Only Rostock virus caused sicked sickness or death in ducks, 9/10 intranasally infected and 6/7 in contact birds showed clinical signs and 2/10 intranasally infected and 3/7 in contact ducks died. Intranasal and in contact pathogenicity indices were calculated for each virus in each bird species and indicated quantitatively the differences in virulence of the four virus strains. Virus isolation and immune response studies indicated that surviving in contact fowls in the Rostock virus group had never been infected but that surviving Australian virus in contact fowls had recovered from infection. Infection was not established in Ulster virus in contact fowls and Australian virus intranasally infected and in contact ducks. The birds in all other groups showed positive virus isolations and a high incidence of positive immune response. The last virus isolation was made at 22 days after intranasal infection of ducks with Ulster virus.

Animals↗
PubMed1977

Isolation of myxoviruses from dead birds arriving at Heathrow Airport, London.

Forty-four haemagglutinating viruses were isolated from the pooled tracheal/cloacal swabs of the dead birds from 170 consignments of caged birds arriving at Heathrow Airport over a period of 6 months. Two isolates were identified as Newcastle disease virus but the remaining 42 were all identified as influenza viruses with Hav 7 Neq 2 antigens. All the consignments from which influenza viruses were isolated originated in India but had widespread destinations. The NDV isolates were from birds originating in central America and destined for Japan.

Animals↗
PubMed1977

Continued studies on the adjuvancy effect of natural and synthetic double-stranded RNA preparations with inactivated Newcastle disease vaccines in fowls.

The adjuvant effect of the natural ds-RNA, BRL 5907, with inactivated Newcastle disease vaccines was confirmed using different oil-based formulations and could be given either as single injections or separately at adjacent sites. A minimum dose level of 0-04 mg BRL 5907 per bird was required for a significant enhancement of antibody levels following vaccination. While the synthetic ds-RNA Poly IC gave a similar response to that observed with BRL 5907, no significant effects could be detected with two other natural ds-RNA materials.

Adjuvants, Immunologic↗
PubMed1976

A comparison between the haemagglutination inhibition and complement fixation tests for Newcastle disease.

The value of the complement fixation (CF) test as a means of assessing the immune response of fowls to Newcastle disease virus was examined using several strains of virus. A close degree of correlation was found between the CF test and the simpler haemagglutination-inhibition (HI) test. Like the HI test, the CF test only gave an indication of the immune status and was not a direct measurement of immunity.

Animals↗
PubMed1975

Newcastle disease.

Newcastle Disease of chickens is of interest in comparative pathology because the causal virus has a wide range of pathogenicity and is of only one antigenic type. The virus can be grown to high titre and is easily titrated. Both live attenuated and inactivated vaccines give effective protection under experimental conditions. Vaccination of commercial chickens is associated with variable results, and it is now possible to investigate the factors which complicate vaccination. These include the presence of interfering respiratory infections, immunosuppressive disease of viral origin, variations in the techniques of vaccination and in the programmes of revaccination. Challenge with lethal virus given by aerosol is severe and allows an accurate assessment of the relationship between serum HI levels and the degree of protection. In the later stages of the immune process most but not all protection is associated with the IgG fraction of serum. There is also an increasing amount of evidence to show that local immunity in the respiratory tract is important in the early stages of the immune process.

Aerosols↗
PubMed1975

Further studies on the adjuvant effect of an interferon inducer (BRL 5907) on Newcastle disease and avian influenza inactivated vaccines.

Vaccination of fowls with inactivated Newcastle disease (ND) virus and avian influenza (AI) virus oil emulsion vaccines containing an interferon inducer (BRL 5907) produced an enhanced immunological response. The Newcastle disease vaccine containing BRL 5907 induced earlier protection to challenge than Newcastle disease vaccine by itself and also produced an increase immune response when administered to day-old maternally immune and susceptible chicks.

Adjuvants, Immunologic↗