Demodicose bovina no Estado da Paraíba

Factors affecting occurrence of demodecosis by Demodex bovis in Sindhi cattle (Bos indicus)

The objective was to evaluate the factors affecting the occurrence of bovine demodecosis from the clinical aspects of injuries, blood profile, and the correlation with weight gain and the season of the year in Sindhi-breed animal management in a tropical environment. Thirty-three Sindhi-breed animals were used: 23 females and 10 males. Clinical examination diagnosed that 90% of the examined animals presented skin lesions characteristic of bovine demodecosis caused by Demodex bovis (P < 0.05). The Sindhi presented a higher fecal parasite egg count and showed a lower body weight gain in the rainy season and a greater weight loss in the drought season (P < 0.05), medium injury predominating, with no effect of sex (P > 0.05). During the drought season, animals clinically infected with bovine demodecosis presented lower red blood cell and platelet counts and total plasma protein, and higher mean corpuscular volume and mean corpuscular hemoglobin concentration, a blood count typical of regenerative macrocytic anemia (P < 0.05). During the rainy season of the year (April to June), the animals showed greater weight gain, but a higher fecal parasite egg count with no effect on the incidence of bovine demodecosis. Infection by gastrointestinal nematodes negatively influenced body weight gain and demodecosis in the animals.

First report of Demodex bovis infestation in bovine besnoitiosis co-infected dairy cattle in Italy

A form of generalized demodectic mange in two dairy cows infected with Besnoitia besnoiti is described. The herd was endemically infected with bovine besnoitiosis; an overall seroprevalence of B. besnoiti antibodies of 23.5%, that increased up to 43.5% considering only cows, was reported. Two out of the cows seropositive to B. besnoiti, at clinical examination presented skin nodules, widespread all over the body, and in particular in anterior regions. Skin biopsies from the region of the neck were collected and the nodules were microscopically examined through compression method. B. besnoiti tissue cysts were not revealed but a semi-solid yellowish content was evidenced with the presence of several mites, morphologically identified as Demodex bovis. Histological examination of skin biopsies evidenced slight acanthosis and hyperkeratosis of the epidermis and superficial dermatitis with oedema and macrophagic and eosinophilic infiltration. Cystic formations located in the deep dermis were lined by metaplastic squamous epithelium and severe cellular infiltration. A treatment with eprinomectin was attempted and clinical improvement of both cows was observed, particularly at the fifteenth day after treatment, with nodules reduced in size and mites in there degenerated. This is the first report of the co-infection of D. bovis infestation and bovine besnoitiosis in cattle. Furthermore, it was demonstrated that D. bovis circulates in the Italian cattle population, but subclinical forms could be underdiagnosed.