Crusted scabies in a rabbit model: a severe skin disease or more?

BackgroundAround 200–300 million people are estimated to be affected by scabies annually worldwide. However, the mechanisms by which this disease may affect the general condition of the host are not entirely clear. The aim of the present study was to evaluate the systemic changes that may accompany crusted scabies in both treated and non-treated experimental animals.MethodsMale New Zealand rabbits were infected with Sarcoptes scabiei var. cuniculi and divided into the following three groups: control, ivermectin-treated, and fluralaner-treated. Several methods were used to evaluate the systemic changes, including histopathological examination of the liver, kidney, heart, and spleen, as well as the measurement of serum biochemical parameters and immunological parameters.ResultsSeveral definite structural and functional changes at the systemic level were revealed, as evidenced by the observed histopathological changes in the tissue sections of internal organs and the highly significant increases in markers of systemic inflammation, serum procalcitonin, and oxidative stress markers. Abnormalities in the liver and renal function results, as well as in the serum lipid profile, were also noted. Additionally, a disorganized immune response was noted, evidenced by a mixed type 1 and type 2 helper T cell response. Although there was notable clinical and parasitological cure in the ivermectin-treated group, the histopathological, biochemical, and immunological markers indicated incomplete resolution. In contrast, the fluralaner-treated group exhibited a nearly complete resolution of changes in these parameters.ConclusionsWe conclude that crusted scabies is a systemic syndrome that can affect several organs besides the skin. Inflammation, oxidative stress, and possibly bacterial infections, are all implicated as underlying mechanisms of tissue damage due to the disease. We recommend that fluralaner, a promising scabicidal agent, should be studied for possible human use, and especially for control programs.