Evidence of immunosuppression in turkey poults affected by rhinotracheitis

Timms, L.M.; Jahans, Keith; Marshall, RN

doi:10.1136/vr.119.4.91

Cited by 14 publications

(4 citation statements)

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“…As demonstrated earlier, the TRT virus has immunosuppressive activity [ 25 - 28 ]. In our study a significant decrease in CD4 + and/or CD8 + T ACC in tracheal mucosa was noted in vaccinated birds 3–7 DPV in Experiments II - IV.…”

Section: Discussionmentioning

confidence: 93%

Development of vaccine-induced immunity against TRT in turkeys depends remarkably on the level of maternal antibodies and the age of birds on the day of vaccination

et al. 2015

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BackgroundAvian Metapneumovirus (aMPV) infections are a huge economical issue for the poultry industry worldwide. Although maternal antibodies do not protect turkey poults against turkey rhinotracheitis (TRT), almost no studies have been conducted so far regarding the impact of these antibodies on vaccine induced immunity development against aMPV infection. We conducted four experiments on commercial turkeys aimed at comparing local humoral and cell mediated immune response of maternally delivered anti-aMPV antibody positive (MDA+; Experiment I and II) and negative (MDA-; Experiment III and IV) turkeys following vaccination with an attenuated live aMPV subtype A vaccine at the day of hatch (Experiment I and III) or at two weeks of age (Experiment II and IV).ResultsRegardless of the birds’ age, vaccination of MDA- turkeys resulted in strong stimulation of CD8+ T lymphocytes in the Harderian gland and tracheal mucosa, whereas vaccination of MDA+ birds stimulated mainly CD4+ T cells in those structures. An increase in the level of anti-aMPV IgY antibodies was noted in the serum (but not in tracheal washings) as early as 7 days after vaccination, but only in birds possessing low levels (MDA+ birds vaccinated at 2 weeks of age) or no maternal anti-aMPV antibodies at the time of vaccination. In MDA+ turkeys vaccinated at hatch, the decrease in serum levels of maternal anti-aMPV antibodies proceeded faster (in comparison to control group), which, together with faster viral clearance, indicates that maternal antibodies can inhibit vaccine virus replication and influence the development of vaccine-induced immunity.ConclusionThis study provides the first documented evidence that the frequency of TRT outbreaks in the field and/or failure of TRT vaccination could be correlated with differences in the immunological status and/or age of vaccinated turkeys.

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Section: Discussionmentioning

confidence: 93%

Development of vaccine-induced immunity against TRT in turkeys depends remarkably on the level of maternal antibodies and the age of birds on the day of vaccination

et al. 2015

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“…I t w a s d e t e c t e d t h a t t r a n s i e n t immunosuppression of birds may occur during the acute stage of aMPV infection (Timms et al, 1986). Multiplication of the virus in the cilia of the upper respiratory cells reduces the amount of mucoid secretion and consequently enhances bacterial replication (Jirjis et al, 2004).…”

Section: Pathogenesismentioning

confidence: 99%

“…Multiplication of the virus in the cilia of the upper respiratory cells reduces the amount of mucoid secretion and consequently enhances bacterial replication (Jirjis et al, 2004). Moreover, the virus could reduce the thymus weight in turkey poults (Timms et al, 1986). The early stage of aMPV infection may inhibit the later efficacy of the turkey hemorrhagic enteritis virus vaccine and induces immune suppression of vaccinated birds .…”

Section: Pathogenesismentioning

confidence: 99%

Avian Metapneumovirus Infection in Poultry Flocks: A Review of Current Knowledge

A. Abd El-Ghany

2023

JTAS

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Avian metapneumovirus (aMPV) is one of the respiratory viruses that cause global economic losses in poultry production systems. Therefore, it was important to design a comprehensive review article that gives more information about aMPV infection regarding the distribution, susceptibility, transmission, pathogenesis, pathology, diagnosis, and prevention. The aMPV infection is characterized by respiratory and reproductive disorders in turkeys and chickens. The disease condition is turkey rhinotracheitis in turkeys and swollen head syndrome in chickens. Infection with aMPV is associated with worldwide economic losses, especially in complications with other infections or poor environmental conditions. The genus Metapneumovirus is a single-stranded enveloped RNA virus and contains A, B, C, and D subtypes. Meat and egg-type birds are susceptible to aMPV infection. The virus can transmit through aerosol, direct contact, mechanical, and vertical routes. The disease condition is characterized by respiratory manifestations, a decrease in egg production, growth retardation, increasing morbidity rate, and sometimes nervous signs and a high mortality rate, particularly in concurrent infections. Definitive diagnosis of aMPV is based mainly on isolation and identification methods, detection of the viral DNA, as well as seroconversion. Prevention of aMPV infection depends on adopting biosecurity measures and vaccination using inactivated, live attenuated, and recombinant or DNA vaccines.

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“…Being an immunosuppressive pathogen, aMPV is able to reduce reactions to phytohaemagglutinin and immune responses to sheep red cells in poults. Infected animals showed lower thymus weight (Timms et al, 1986). Furthermore, it has been shown that aMPV can interfere with HEV vaccines and subsequently, reduce immune response in turkeys (Chary et al, 2002).…”

Section: Respiratory Virusesmentioning

confidence: 99%

Virus-induced immunosuppression in turkeys (<i>Meleagris gallopavo</i>): A review

Kaboudi¹

2020

Open Vet J.

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Evidence of immunosuppression in turkey poults affected by rhinotracheitis

Cited by 14 publications

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Development of vaccine-induced immunity against TRT in turkeys depends remarkably on the level of maternal antibodies and the age of birds on the day of vaccination

Development of vaccine-induced immunity against TRT in turkeys depends remarkably on the level of maternal antibodies and the age of birds on the day of vaccination

Avian Metapneumovirus Infection in Poultry Flocks: A Review of Current Knowledge

Virus-induced immunosuppression in turkeys (<i>Meleagris gallopavo</i>): A review

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