Parotid gland
Mumps is seen to be a common cause of parotid gland swelling - 85% of cases occur in children younger than 15 years. The disease is highly contagious and spreads by airborne droplets from salivary, nasal, and urinary secretions. Symptoms include oedema in the area, trismus as well as otalgia. The lesion tends to begin on one side of the face and eventually becomes bilateral. The transmission of the paramyxovirus is by contact with the infected persons saliva. Initial symptoms tend to be a headache and fever. Mumps is not fatal, however further complications can include swelling of the ovaries or the testes. Diagnosis of mumps is confirmed through viral serology, management of the condition includes hydration and good oral hygiene of the patient requiring excellent motivation. However, since the development of the mumps vaccine, given at the age of between 4–6 years, the incidence of this viral infection has greatly reduced. This vaccine has reduced the incidence by 99%.
Mites of livestock
The clinical manifestation of infestation with psoroptic mites is usually called mange and sometimes scabies, but the skin disease of sheep caused by "Psoroptes ovis" is often known locally as sheep scab. This species may affect its hosts severely enough to reduce their gain in weight. Costs to farmers of controlling sheep-scab in Britain were at £8 million (US$12 million) annually in 2005. Transmission between hosts is readily accomplished by contagion during flocking contact and also on fomites such as scraps of sheep's wool because these relatively large and robust mites can survive for one to two weeks off their host. "Psoroptes ovis" infests the superficial layers of the skin. Irritation of the outer skin by the mite's mouthparts and saliva results in a complex form of cutaneous hypersensitivity and inflammatory exudation of serum and fresh cells. The mites feed on this moist exudate. The skin loses its hair (depilation) at the sites of infestation and this may be extensive. As a result of the movement of the mites into areas of fresh skin, large scabs accumulate on the raw skin left behind. The mites cause intense pruritus (itching). In cases of heavy infestations, the host grooms compulsively, aggravating the depilation, and it may become mentally distressed. "Psoroptes ovis" infests sheep worldwide and can be a serious welfare and animal-production problem for sheep farmers.
Infestations of cattle with mites of the similar genus "Chorioptes", in combination with "Sarcoptes" mite infestation, has been shown to cause a failure to gain body weight by 15.5 kg to 37.2 kg over a two-month period compared to cattle without the mites.