A broad-spectrum antibiotic effective against both Gram-negative and Gram-positive bacteria, Ornex Plus treats avian fever. This disease is common to both birds and humans and is the most serious respiratory disease affecting birds. It may develop into complex avian fever. The disease appears in birds infected with pneumonia, and the infection is caused by chlamydia (a very small microbe that is excreted in feces, tears, or mucous fluids that flow from the mouth and throat and is caused by bacteria that are susceptible to doxycycline or spiramycin).