Demodex phylloides infection in swine reared in a peri-urban family farm located on the outskirts of the Metropolitan Region of São Paulo, Brazil

Abstract

This paper reports the occurrence of porcine demodicosis caused by the mite Demodex phylloides in hogs reared in a peri-urban family farm located in Francisco Morato, a municipality of the Metropolitan Region of São Paulo, capital city of the state of São Paulo, Brazil. In a parcel of forty Landrace – Large White cross hogs, approximately four months old, four animals presented severe skin lesions in the form of small nodules over their entire body, especially in the periocular region, snout, lower abdomen and flanks. Two hogs had to be euthanized for animal welfare reasons, which enabled post-mortem examination. Skin scrapings revealed eggs, larvae, nymphs and adults of D. phylloides. Purulent subcutaneous nodules with intense parasitic folliculitis and intense perifollicular inflammatory reaction were present. Enterobacteria and coagulase-positive Staphylococcus spp. were isolated from the skin pustules. Necropsy revealed milk spotted liver, enteritis and enlargement of mesenteric lymph nodes. Protozoa (Eimeria spp. and Balantidium sp.), helminth eggs (Ascaris suum, Trichuris suis and strongyles) and Brachyspira spp. were found in faeces. Staphylococcus spp. and enterobacteria were isolated from internal organs. All remaining hogs were treated with ivermectin at a daily oral dose of 0.45 g/kg of feed, during seven days. Fifteen days after treatment, remission of symptoms was observed in the surviving animals with demodicosis; absence of mites was confirmed by skin scraping examinations. The hogs were reared under poor environmental, nutritional and sanitary conditions, resulting in multimorbidity and immunosuppression. Severe clinical porcine demodicosis was triggered when the animals were castrated. Family pig farmers had been suffering economic losses due to the stunted growth of the herd. In addition to that, the lesions found on the skin and in the internal organs would result in condemnation of meat and viscera for human consumption. As part of a Public Policies Project, farm facilities were renovated with governmental aid, while family farmers received training. Good management practices and biosecurity measures were introduced in the herd. Educative policies and financial support were important to guide family pig farmers towards better husbandry practices, allowing them to raise healthy hogs in compliance with market demands.