Highly pathogenic avian influenza (HPAI) is considered as one of the most devastating poultry diseases. It is imperative to immediately report any known outbreaks to the World Organization for Animal Health. Early detection of infected birds is of paramount importance to control virus spread, thus minimizing the associated economic loss. In this study, thermal imaging camera devices were used to detect change in the maximum surface temperature (MST) of chickens (n = 5) and ducks (n = 2) as an early indicator of experimental HPAI infection. The MST of both chickens and ducks increased at least 24 h before the manifestation of clinical signs of HPAI infection, depending on the severity of the infection. The basal MST was recorded for broiler chickens housed under small pen and normal farm conditions without intentional infection. A threshold cutoff of MST was established based on the circadian rhythm of normal MST. This study suggests that thermal imaging of chickens and ducks is a promising tool to screen any potential HPAI-infected flock in order to expedite HPAI diagnosis.

Avian influenza virus infection, one of the most important diseases recognized in the poultry industry, is known to cause changes in cytokine and serum protein levels. However, the normal ranges and/or age-dependent changes in important cytokines and serum proteins associated with influenza infection have not been fully elucidated. In this study, the levels of cytokines (interleukin-1β, interleukin-6, and interferon-γ) and serum proteins (vitamin D binding protein and ovotransferrin) were determined in 1-week-to 4-week-old broilers at 1-week intervals after challenge with a low pathogenic influenza virus. The results showed that the physiological levels of cytokines and serum proteins varied with aging during the 4 weeks. The levels of interleukin-1β and interleukin-6 increased from 20% to 35% after influenza infection compared to those in the negative control group, indicating that these cytokines may be used to monitor disease progression.