Role of aflatoxin toxicity on transmissibility and pathogenicity of H9N2 avian influenza virus in turkeys

[tetano]

Avian Pathol. 2015 May 1:1-22. [Epub ahead of print]
Role of aflatoxin toxicity on transmissibility and pathogenicity of H9N2 avian influenza virus in turkeys.

Umar S¹, Younus M, Rehman MU, Aslam A, Shah MA, Munir MT, Hussain S, Iqbal F, Fiaz M, Ullah S.
Author information

Abstract

The study was conducted to investigate the role of aflatoxin on the infectivity and transmissibility of H9N2 AI virus. The experiment was performed on 80 non-vaccinated turkeys, divided into four groups of 20 birds each. Group A was kept as non-infected and a non-treated negative control; group B was inoculated intratracheally with H9N2 AI virus (1 ? 10⁷ EID₅₀) at 4 week of age; group C was fed on a diet containing 0.5 ppm aflatoxin from day one through the entire experiment period and group D was fed on diet containing 0.5 ppm aflatoxin like Group C but inoculated intratracheally with H9N2 AI virus (1 ? 10⁷ EID₅₀) at the 4^th week of age and then mixed with na?ve birds. Infected and contact birds showed clinical signs of different severity, showing the most prominent disease signs in birds of the aflatoxin+H₉N₂ group. All infected birds showed virus shedding, however, the pattern of virus shedding was different for birds of the aflatoxin+H₉N₂ group showing pronounced virus secretion. Similarly, efficient transmission of virus was observed between infected and contact birds, but more prominent virus transmission was seen in those birds inoculated and fed aflatoxin-treated diet. Moreover, significant lower antibody titres against H9N2 AIV were observed in birds fed aflatoxin-treated diet, indicating an immunotoxic nature of aflatoxin as the reason for poor seroconversion. Similarly, decreased IFN_γ mRNA expression and higher mortality (35%) suggest an immunotoxic and immunosuppressive effect of aflatoxin leading to enhanced pathogenesis of H9N2 viruses in aflatoxin-fed birds. The immunosuppressive nature of aflatoxin might delay influenza virus clearance and this may be one of the reasons for increased pathogenicity of H9N2 LPAI viruses in turkeys under field conditions.


PMID: 25932659 [PubMed - as supplied by publisher]

[Emily]

.5 ppm = 500 ppb

http://vicam.com/mycotoxin-blog/six_states

Oct 29 2012
Six States Receive FDA Waiver to Allow Blending of Aflatoxin-Contaminated Corn

The FDA has approved six states to receive an exemption from 'no-blending' rules for aflatoxin contaminated corn, bringing some relief to the drought-ridden US corn belt. Iowa received the first approval on September 18, followed by Illinois, Indiana, Kansas, Nebraska and Oklahoma....

http://www.reuters.com/article/2012/09/19/usa-drought-aflatoxin-iowa-idUSL1E8KJ83820120919

Markets | Wed Sep 19, 2012 1:52pm EDT U.S. FDA relaxes aflatoxin rules for Iowa grain handlers

Under FDA guidelines, certain types of animal feed can contain an aflatoxin concentration of up to 300 ppb. Human foods must contain less than 20 ppb, while the threshold for milk is even lower at 0.5 ppb.
Last month, Iowa began requiring the state's dairy processors to test all milk received in the state for aflatoxin.
FDA generally forbids grain handlers from blending off corn containing aflatoxin by mixing it with "clean" grain, but it has relaxed this policy during years of widespread aflatoxin problems, upon the request of state officials.