Viral infections in animals occasionally develop potentially fatal diseases that affect almost all organs. Especially in zoonotic diseases, the causative agents that usually exist in animals can be transmitted between animal species to humans directly or via a vector. Throughout recent history, disease outbreaks and pandemics including SARS, H7N9, Ebola, and COVID-19, have led to a dramatic loss of human life worldwide and harmed economic growth. The most effective strategies for the control of disease are vaccination and early diagnosis. Vaccines directed against viral and bacterial pathogens prevent catastrophic losses of life in humans, other animals, and plants, and are considered among the greatest public health achievements. Rapid and accurate detection of pathogens and identification of the aetiologic agent play a crucial role at every step of disease management. In the case of zoonotic illnesses, early detection of wildlife aids in the establishment of a surveillance system, allowing for the introduction of efficient and timely disease control interventions to prevent transmission from animal to human. At present, variations and deletions in the genome of the virus are of common occurrence during evolution, coupled with the new emerging disease and cross-species disease transmission, which are increasing the potential for the transmissibility and severity of the disease. For this reason, developing safe and effective vaccines, and enhancing the sensitivity and specificity of the diagnostic methods are urgently required. The scope of this research topic will share and discuss findings in the areas of diagnosis of viral diseases or vaccine development for all animal species, including terrestrial and aquatic mammals, fishes, insects, birds, etc.