In February 2024, we received an interesting case through the disease surveillance program of the Agency for Nature and Forests (ANB). A severely weakened fox was found in the veranda of a residential home. Staff from the Wildlife Rescue Center (VOC) were able to capture the animal without much difficulty and transfer it to a veterinarian. Due to the advanced stage of its condition, it was decided to euthanize the fox and send it for an necropsy to better understand its illness.
The fox, an adult male, was in very poor condition and exhibited extensive skin lesions, consisting of crusts, bald patches, and thickened skin, mainly concentrated around the ears, eyes, and hindquarters. These symptoms strongly indicated an infection with mange mites.
Under the microscope, numerous mange mites—likely Sarcoptes scabiei var. vulpes—were identified in skin scrapings. These tiny parasitic mites (2 to 4 mm) burrow into the skin, where inflammatory fluids and dead tissue lead to intensely itchy crusts on the fox’s skin. These crusts cause excessive scratching, resulting in extensive wounds that can easily become infected.
Histological samples showed parakeratotic hyperkeratosis and "scalloping," with a mixed inflammatory response consisting of lymphocytes, plasma cells, and some eosinophils, along with intralesional mites in the upper skin layer (red arrow).
These findings, combined with the fox's clinical presentation, suggest a type B mange infection, based on the classification by Nimmervoll et al. (2013). Mange caused by Sarcoptes scabiei progresses through three stages:
Early stage (A): Few lesions, thin crusts, mild hair loss
Widespread infection (B): Extensive skin lesions, thick crusts, widespread hair loss, strong odor, and weight loss (this stage is typically fatal)
Recovery or low-level infection (C): Few lesions, no crusts, severe hair loss, darkened skin (hyperpigmentation)
The infected fox exhibited characteristic signs of type B mange. Without fur, a fox is unable to regulate its body temperature, especially in cold and/or wet conditions, often leading it to seek shelter in buildings—such as in this case, inside a veranda.
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