Skip to main content
ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Exotic & Emerging Avian Viral Diseases Research » Research » Publications at this Location » Publication #305601

Research Project: Intervention Strategies to Control and Prevent Disease Outbreaks Caused by Avian Influenza and Other Emerging Poultry Pathogens

Location: Exotic & Emerging Avian Viral Diseases Research

Title: Experimental co-infection of chickens with lentogenic, mesogenic and velogenic strains of Newcastle disease viruses and highly pathogenic avian influenza viruses

Author
item Pantin-jackwood, Mary
item Costa-hurtado, Mar - US Department Of Agriculture (USDA)
item Afonso, Claudio
item Miller, Patti
item Shepherd, Eric
item Smith, Diane

Submitted to: European Scientific Working Group on Influenza
Publication Type: Abstract Only
Publication Acceptance Date: 6/13/2014
Publication Date: 9/14/2014
Citation: Pantin Jackwood, M.J., Costa-Hurtado, M., Afonso, C.L., Miller, P.J., Shepherd, E.M., Smith, D.M. 2014. Experimental co-infection of chickens with lentogenic, mesogenic and velogenic strains of Newcastle disease viruses and highly pathogenic avian influenza viruses [abstract}. The Fifth ESWI Influenza Conference, September 14-17, 2014, Riga, Latvia. Paper No: SPB2P12. P50.

Interpretive Summary: Avian influenza virus (AIV) and Newcastle disease virus (NDV) are two of the most economically important viruses affecting poultry. Co-infection of chickens with these viruses is difficult to recognize. Co-infections also may affect the severity of clinical signs, virus shedding and virus transmission. In this study we infected chickens with lentogenic, mesogenic or velogenic strains of NDV, and high pathogenicity (HP) AIV’s, by giving the viruses simultaneously or sequentially. Clinical signs, lesions, presence of the viruses in tissues, duration and titer of virus shedding, and seroconversion to both viruses were evaluated. We found that previous infection of chickens with mesogenic and velogenic strains of NDV, but not a lentogenic NDV strain, interfered with replication of a HPAIV subtype H5N2 when given at a high titer dose 2 days after NDV inoculation; however high mortality was still observed. Remarkably, chickens did not become infected or presented with significantly less mortality when given lower titers of the same HPAIV or another HPAIV (subtype H7N3)3 days after the mesogenic NDV. In conclusion, chickens previously infected with NDV show less replication of HPAIV in tissues and consequently less disease and mortality. The information obtained from these studies helps understand the possible interactions and outcomes of infection (disease and virus shedding) when AIV and NDV co-infect birds in the field.

Technical Abstract: Background: Avian influenza virus (AIV) and Newcastle disease virus (NDV) are two of the most economically important viruses affecting poultry worldwide. Co-infections of poultry with AIV and NDV are a problem from the clinical point of view and diagnosis of these viruses, but little is known on the interactions between these two viruses when infecting birds. AIV and NDV can produce from mild to moderate upper respiratory diseases in their low pathogenic forms [lentogenic or mesogenic NDV and low pathogenicity (LP) AIV], to severe systemic diseases with high mortality in their more virulent forms [velogenic NDV and highly pathogenic (HP) AIV]. Exposure to NDV, either live vaccines or field strains, is nearly unavoidable for commercial and non-commercial poultry worldwide and co-infections with AIV are known to occur. The objective of this study was to determine if co-infection of chickens with different strains of NDV could affect the outcome of infection with HPAI viruses. Methods: We conducted three experiments in which we infected chickens with lentogenic, mesogenic or velogenic strains of NDV, and high pathogenicity (HP) AIV’s, by giving the viruses simultaneously or sequentially. Pathogenesis (clinical signs, lesions), presence of the viruses in tissues, duration and titer of virus shedding, and seroconversion to both viruses were evaluated. Results: We found that previous infection of chickens with mesogenic and velogenic strains of NDV (Pigeon 84 and CA2002 strains), but not a lentogenic NDV strain (LaSota) interfered with replication of a HPAIV (A/Ck/Queretaro/14588-19/95 H5N2) when given at a high titer dose [106.3 50% egg infectious dose (EID50)] 2 days after NDV inoculation; however high mortality was still observed. Interestingly, chickens were refractory to infection, as measured by lack of disease, virus shedding and seroconversion, when given lower titers (105.3 EID50) of the same HPAIV 3 days after the mesogenic NDV (Pigeon 84), indicating that virus titer and timing of the second infection might play a role in virus interference. This was corroborated by the results of a third study in which 10% mortality was observed among chickens that received 105EID50 of a different HPAIV [A/chicken/Jalisco/CPA-12283-12/2012 (H7N3)] 3 days after the same mesogenic NDV was given, when compared to 80% mortality observed in chickens challenged only with the HPAIV. Conclusions: Previous infection of chickens with NDV can affect HPAIV replication in tissues and consequently prevent disease and mortality. This virus interference will depend on the virulence and titer of the co-infecting viruses, and the timing of the infections. The information obtained from these studies helps understand the possible interactions and outcomes of infection (disease and virus shedding) when AIV and NDV co-infect birds in the field.