Red Fox - Diseases and Parasites

Diseases and Parasites

Red foxes are the most important rabies vector in Europe. In London, arthritis is not uncommon in foxes, being particularly frequent in the spine. Foxes may be infected with leptospirosis and tularemia, though they are not overly susceptible to the latter. They may also fall ill from listerellosis and spirochetosis, as well as acting as vectors in spreading erysipelas, brucellosis and tick-born encephalitis. A mysterious fatal disease near Lake Sartlan in the Novosibirsk Oblast was noted among local red foxes, but the cause was undetermined. The possibility was considered that it was caused by an acute form of encephalomyelitis, which was first observed in captive bred silver foxes. Individual cases of foxes infected with Yersina pestis are known.

Red foxes are not overly infested with fleas. Species like Spilopsyllus cuniculi are probably only caught from the fox's prey species, while others like Archaeopsylla e. erinacei are caught whilst travelling. Fleas which actively feed on red foxes include Pulex irritans, Ctenocephalides canis and Paraceras melis. Ticks such as Ixodes ricinus and I. hexagonus are not uncommon in foxes, and are typically found on nursing vixens and kits still in their earths. The louse Trichodectes vulpis specifically targets foxes, but is found infrequently. The mite Sarcoptes scabiei is the most important cause of mange in red foxes. It causes extensive hair loss, starting from the base of the tail and hindfeet, then the rump before moving on to the rest of the body. In the final stages of the condition, foxes can lose most of their fur, 50% of their body weight and may gnaw at infected extremities. In the epizootic phase of the disease, it usually takes foxes 4 months to die after infection. Other endoparasites include Demodex folliculorum, Notoderes, Otodectes cynotis (which is frequently found in the ear canal), Linguatula serrata (which infects the nasal passages) and ringworms.

Up to 60 helminth species are known to infect foxes in fur farms, while 20 are known in the wild. Several coccidian species of the genera Isospora and Eimeria are also known to infect them. The most common nematode species found in fox guts are Toxocara canis and Uncinaria stenocephala, Capillaria aerophila and Crenosoma vulpis, the latter two infect their lungs. Capillaria plica infect the fox's bladder. Trichinella spiralis rarely affects them. The most common cestode species in foxes are Taenia spiralis and T. pisiformis. Others include Echinococcus granulosus and E. multilocularis. Eleven trematode species infect red foxes.