Systemic distribution of different low pathogenic avian influenza (LPAI) viruses in chicken

Post, J.; Geus, Eveline D. de; Vervelde, Lonneke; Cornelissen, J.B.W.J.; Rebel, Johanna M.J.

doi:10.1186/1743-422x-10-23

Cited by 34 publications

(23 citation statements)

References 19 publications

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“…Several recent reports pointed out that LPAIV may spread systemically in chicken. After intranasal or intratracheal infection with various LPAIV of subtypes H5, H7 and H9 viral RNA was found by RT-PCR in a broad range of tissues beyond the respiratory and gastrointestinal tract and H7N7 virus could be isolated from several tissues (Post et al, 2012(Post et al, , 2013. Thus, one might speculate that systemic, but asymptomatic infection of LPAIV might occur more often than previously anticipated.…”

Section: Discussionmentioning

confidence: 92%

Mimicking the passage of avian influenza viruses through the gastrointestinal tract of chickens

Han

Bertzbach

Veit

2019

Veterinary Microbiology

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In contrast to human influenza viruses that replicate in the respiratory tract and are airborne transmitted, avian viruses also replicate in gut epithelial cells and are transmitted via the fecal-oral route. On this route, the virus is exposed to destructive fluids of the digestive tract, which are acidic and contain the proteases pepsin (gizzard) or chymotrypsin and trypsin (intestine). Only the latter enzyme activates virus by cleaving hemagglutinin (HA) into HA 1 and HA 2 subunits.We mimicked the passage of viruses through the gastrointestinal tract by treating them with digestive fluids from chicken and determined titers and integrity of HA by western-blot. Gizzard fluid completely inactivated virions and degrades HA even at a high dilution, but only if the pH was kept acidic. If the fluid is diluted with neutral buffer (mimicking virus uptake with seawater) particles were more resistant. Virions containing an uncleaved HA were even activated suggesting that gastric juice contains a trypsin-like protease. Undiluted intestinal fluid inactivated particles and destroyed HA, but diluted fluid activated virions. A virus isolated from the duck´s intestine is more tolerant against intestinal fluid compared to fowl plague virus suggesting that the former is better adapted to grow in the intestine. We also demonstrate that influenza viruses replicate to high titers in a novel chicken epithelial gut cell line. While viruses with a monobasic HA cleavage site require addition of trypsin, these cells effectively process HA with a polybasic cleavage site, which could be blocked with an inhibitor of the cellular furin protease.

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Section: Discussionmentioning

confidence: 92%

Mimicking the passage of avian influenza viruses through the gastrointestinal tract of chickens

Han

Bertzbach

Veit

2019

Veterinary Microbiology

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“…Although studies with (LPAI)H5N1 show that LPAI strains are mostly localized in the lungs in chickens, a recent study showed that systemic distribution of LPAI H7N1, H7N7, H5N2, and H9N2 strains does occur in chickens, with virus detected and isolated in multiple organs, including lung, brain, intestine, peripheral blood mononuclear cells, heart, liver, kidney, and spleen [31, 32]. During 2012, wild birds (sacred Ibis and Egyptian geese) sampled in bird die-offs in Gauteng province tested positive for (LPAI)H7N1 in heart, spleen, and brain samples (Zoonoses Research Unit, University of Pretoria and National Institute for Communicable Diseases, and confirmed by the Onderstepoort Veterinary Institute) (unpublished data).…”

Section: Discussionmentioning

confidence: 99%

Risk of Human Infections With Highly Pathogenic H5N2 and Low Pathogenic H7N1 Avian Influenza Strains During Outbreaks in Ostriches in South Africa

Venter

Treurnicht

Buys

et al. 2017

The Journal of Infectious Diseases

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Background Risk factors for human infection with highly pathogenic (HP) and low-pathogenic (LP) avian influenza (AI) H5N2 and H7N1 were investigated during outbreaks in ostriches in the Western Cape province, South Africa. Methods Serum surveys were conducted for veterinarians, farmworkers, and laboratory and abattoir workers involved in 2 AI outbreaks in the Western Cape province: (1) controlling and culling of 42 000 ostriches during (HPAI)H5N2 outbreaks in ostriches (2011) (n = 207); (2) movement control during (LPAI)H7N1 outbreaks in 2012 (n = 66). A third serosurvey was conducted on state veterinarians from across the country in 2012 tasked with disease control in general (n = 37). Antibodies to H5 and H7 were measured by means of hemagglutination inhibition and microneutralization assays, with microneutralization assay titers >40 considered positive. Results Two of 207 (1%) participants were seropositive for H5 and 4 of 207 (2%) for H7 in 2011, compared with 1 of 66 (1.5%) and 8 of 66 (13%) in 2012. Although individuals in all professions tested seropositive, abattoir workers (10 of 97; 10.3%) were significantly more at risk of influenza A(H7N1) infection (P = .001) than those in other professions (2 of 171;1.2%). Among state veterinarians, 4 of 37(11%) were seropositive for H7 and 1 of 37 (2.7%) for H5. Investigations of (LP)H7N1-associated fatalities in wild birds and quarantined exotic birds in Gauteng, AI outbreaks in poultry in KwaZulu-Natal, and ostriches in Western Cape province provide possible exposure events. Conclusion (LPAI)H7N1 strains pose a greater infection-risk than (HPAI)H5N2 strains to persons involved in control of outbreaks in infected birds, with ostrich abattoir workers at highest risk.

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“…Reports on the systemic detection of LPAIV H5N2, H7N1, H7N7 or H9N2 by real-time reverse transcription PCR (RRT-PCR) in organs and muscles of experimentally infected chickens were also provided but few of these samples (H7N7 LPAIV from samples with a high viral RNA load (Ct ≤ 35 in qPCR) were confirmed by virus isolation (Post et al, 2013). There are reports on the isolation of LPAIV H7N1 in blood of infected turkeys or detection of LPAIV genome in blood, breast and thigh (by RRT-PCR) (Toffan et al, 2008).…”

Section: Assessment Of Lpaiv Transmission Via Raw Poultry Meatmentioning

confidence: 99%

Assessment of low pathogenic avian influenza virus transmission via raw poultry meat and raw table eggs

Gonzáles¹,

Roberts²,

Śmietanka³

et al. 2018

EFS2

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A rapid qualitative assessment has been done by performing a theoretical analysis on the transmission of low pathogenic avian influenza (LPAI) via fresh meat from poultry reared or kept in captivity for the production of meat (raw poultry meat) or raw table eggs. A predetermined transmission pathway followed a number of steps from a commercial or non‐commercial poultry establishment within the EU exposed to LPAI virus (LPAIV) to the onward virus transmission to animals and humans. The combined probability of exposure and subsequent LPAIV infection via raw poultry meat containing LPAIV is negligible for commercial poultry and humans exposed via consumption whereas it is very unlikely for non‐commercial poultry, wild birds and humans exposed via handling and manipulation. The probability of LPAIV transmission from an individual infected via raw poultry meat containing LPAIV is negligible for commercial poultry and humans, whereas it is very unlikely for non‐commercial poultry and wild birds. The combined probability of exposure and subsequent LPAIV infection via raw table eggs containing LPAIV is negligible for commercial poultry and humans and extremely unlikely to negligible for non‐commercial poultry and wild birds. The probability of LPAIV transmission from an individual infected via raw table eggs containing LPAIV is negligible for commercial poultry and humans and very unlikely to negligible for non‐commercial poultry and wild birds. Although the presence of LPAIV in raw poultry meat and table eggs is very unlikely to negligible, there is in general a high level of uncertainty on the estimation of the subsequent probabilities of key steps of the transmission pathways for poultry and wild birds, mainly due to the limited number of studies available, for instance on the viral load required to infect a bird via raw poultry meat or raw table eggs containing LPAIV.

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Systemic distribution of different low pathogenic avian influenza (LPAI) viruses in chicken

Cited by 34 publications

References 19 publications

Mimicking the passage of avian influenza viruses through the gastrointestinal tract of chickens

Mimicking the passage of avian influenza viruses through the gastrointestinal tract of chickens

Risk of Human Infections With Highly Pathogenic H5N2 and Low Pathogenic H7N1 Avian Influenza Strains During Outbreaks in Ostriches in South Africa

Assessment of low pathogenic avian influenza virus transmission via raw poultry meat and raw table eggs

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