Redescription of a human-infesting European trombiculid mite Kepkatrombicula desaleri (Acari: Trombiculidae) with data on its mouthparts and stylostome

A.B. Shatrov and A.A. Stekolnikov

International Journal of Acarology, 37(Suppl. 1): 176-193 (2011).

S U M M A R Y

External morphology of trombiculid larvae Kepkatrombicula desaleri (Methlagl, 1928) collected on chamois in Alps with special consideration of the mouth apparatus was studied by scanning electron microscopy (SEM). Standard morphological description of this species using optical microscopy is also given, with the discussion on its taxonomy. Neotype of K. desaleri is designated. Feeding tube or stylostome formed by larvae in the host skin was examined using histological methods. Larvae of this species possess an unusual organization of the apical portions of the hypostome forming a soft sucker disk. The latter being applied to the stratum corneum of the host epidermis provides an additional pumping effect for engorgement of food through the long stylostome that may extend deep into the dermis at different angles to the surface of the epidermis. Stylostome corresponds to the mesenchymal type of stylostome. Skin reaction is strong and is expressed in the intensive infiltration of the inflammatory foci with leukocytes and erythrocytes. Besides fluid components of the inflammatory focus and cellular debris, larvae also may uptake the whole erythrocytes. Edema, scab formation, as well as the epidermal hyperplasia and hyperkeratosis are not characterized for feeding of larvae of this species. Stylostome organization and the character of the skin inflammatory reaction suggest that big animals like chamois and probably humans are not natural hosts for larvae of this species that may serve as vector of Rickettsiae and causes trombidiosis in man.