Volume 2 - Issue 3, May - June 2026

The emergence of Bluetongue virus (BTV) in Egypt, along with its association with ill-bled condemned sheep carcasses, highlights the growing effects of environmental change on the epidemiology of vector-borne diseases. Rising temperatures facilitate the development of vector habitats, increasing the risk of transmission and potentially leading to severe outcomes such as ill-bleeding and the condemnation of entire carcasses. A detailed case-series study was conducted at the Al-Basatin automated slaughterhouse and 15 May SemiAutomated Abattoir in Cairo, spanning from June 2024 to May 2025, involving 100 sheep carcasses that were entirely condemned. A total of nineteen ill-bled carcasses underwent molecular and biochemical analysis for the detection of BTV using RT-PCR, as well as for oxidative stress biomarkers including total antioxidant capacity (TAC), malondialdehyde (MDA), and reduced glutathione (GSH). In addition, the expression of genes related to heat stress, including heat shock protein 70 KDa protein 1A (HSP70) and bradykinin receptor B1 (BDKRB1), was assessed. Furthermore, key signaling molecules involved in bluetongue virus (BTV)–induced immune responses, namely interferon regulatory factor 3 (IRF3) and signal transducer and activator of transcription 2 (STAT2), were analyzed. The BTV-positive ill-bled animals were subjected to histopathological examination and immunohistochemistry for cyclooxygenase-2 (COX-2) and inducible Nitric Oxide Synthase (iNOS). Additionally, Meteorological records from national climate monitoring agencies were also used to estimate the Temperature–Humidity Index for sheep (THIₛₕₑₑₚ) on the dates of sample collection. Molecular testing has verified the presence of BTV RNA in 63.2% of the examined heart and lung samples. The gross and histopathological observations indicated degeneration and necrosis in parenchymatous organs such as the heart, liver, kidney, and lung, in all ill-bled condemned sheep carcasses, which were consistent with BTV infection. This was further supported by the elevated expression of COX-2 and iNOS. The ill-bleeding observed in sheep carcasses demonstrated a strong and statistically significant correlation with the level of heat stress, as evaluated by THI (p = 0.023). Biochemical analyses showed increased levels of MDA, alongside decreased concentrations of TAC, GSH with variable levels of HSP70, BDKRB1, IRF3 and STAT2, in heart and lung tissues. Indicating heightened oxidative stress coupled with reduced antioxidant capacity under conditions of heat stress. Our current findings highlight the impact of climate extremes in animal disease dynamics and indicating a substantial correlation between heat stress and ill-bleeding in sheep, mediated by BTV infection and oxidative stress.

Ashraf Kassem, Marwa Khattab, Elshaimaa Ismael, Aya Yassin, Dalia Hamza, Ahmed Osman,"Assessment of Climate-Related Bluetongue Virus in Ill-Bled Sheep Carcasses from Egyptian Abattoirs" International Journal of Advanced Multidisciplinary Research and Educational Development, V2(3): Page(439-454) May-June 2026. ISSN: 3107-6513. www.ijamred.com. Published by Scientific and Academic Research Publishing.