India, Aug. 22 -- Deer across the United States have been showing strange, tumour-like growths on their bodies, alarming wildlife watchers and social media users who have been documenting the unusual sightings.

These deformities, sometimes appearing as large bubbles or warts on the face, neck, or legs, have been photographed from New York to Pennsylvania to Wisconsin over the past two months.

Wildlife experts say the culprit is a condition known as deer cutaneous fibroma, more commonly referred to as "deer warts." The disease is caused by a papillomavirus that spreads among deer populations nationwide, and reports of it are increasing this summer.

"Papillomas are most frequently seen during the late summer and into the fall, probably d...