Pathology and diagnosis of proliferative and ulcerative dermatitis associated with Tunga penetrans infestation in cattle

Abstract

Tunga penetrans is the smallest biting flea known. In cattle, infestation by T. penetrans (tungiasis) typically affects the skin of the distal legs, udder, prepuce, and perianal area. A detailed clinical and pathologic description of bovine tungiasis, together with electron microscopy and molecular diagnostics to establish the identity of the parasite are described. Ninety percent of the cows and heifers and 80% of the bulls in a herd in northwest Argentina had proliferative and ulcerative skin lesions affecting the coronary band, interdigital space, heels, and rudimentary toes of the fore and/or rear limbs, teats, and/or prepuce. These proliferative lesions had multiple large cavities filled with hemorrhagic fluid, necrotic debris, and Tunga spp. parasites. Histologically, the skin showed diffuse papillary epithelial hyperplasia with severe orthokeratotic hyperkeratosis, and it was multifocally ulcerated and inflamed. Multifocally, sections of arthropod parasites were observed embedded in the epidermis and dermis with the posterior end toward the surface. Images of wet mounts and scanning electron microscopy of the parasite showed morphologic characteristics compatible with Tunga spp. Polymerase chain reaction followed by sequencing of the cytochrome c oxidase subunit II and the internal transcribed spacer region indicated 99% homology to published T. penetrans sequences. Tungiasis should be considered as a differential diagnosis for proliferative lesions in skin of cattle.

Successful Treatment of Severe Tungiasis in Pigs Using a Topical Aerosol Containing Chlorfenvinphos, Dichlorphos and Gentian Violet

“…In addition to proper animal husbandry practices, which are often difficult to implement in impoverished villages with very poor infrastructure, treatment protocols for infected animals would be highly beneficial. However, there is no approved drug treatment for animal tungiasis [ 36 , 37 ]. Studies aimed at improving this situation are very scarce.…”

Clinical and pathological aspects of first report of Tunga penetrans infestation on southern brown howler monkey (Alouatta guariba clamitans) in Rio Grande do Sul, Brazil

“…This was also observed in this study, possibly related to the histological incidence of the cut surface of the parasite. Similarly, previous studies have shown the histopathological features of T penetrans in humans 20 and in cattle, 19 as well as scarcely in monkeys 12 and gorillas; 11 however, there are no studies with regard to the pathological and parasitological features of T penetrans in southern brown howler monkeys.…”

“…In the southern brown howler monkey 2, the clinical condition was severe at the clinical examination, and the primate died shortly after arrival, allowing to perform a more detailed pathological and parasitological investigation, with identification of T penetrans as the etiological agent. Microscopically, the presence of the head, exoskeleton, hypodermal layer, striated muscles, tracheal rings, digestive tract, female reproductive tract, and developing eggs, as observed in the southern brown howler monkey 2, are histological features of T penetrans infestation in humans 16,17,18 and in cattle 19 . Some structures, such as the exoskeleton, hypodermal layer, tracheae, digestive tract, and developing eggs, are more frequently found than the striated muscles and the head in human biopsies 16 .…”

“…TA B L E 1 Evolution of the laboratory findings of the southern brown howler monkey 1 (Alouatta guariba clamitans), from rescue (day zero) to clinical discharge in twenty-fourth day Cutaneous lesions of acanthosis and parakeratotic hyperkeratosis, observed in the second case, have previously been described in humans infested with T penetrans. 18,20 Although inflammation associated with the flea has been described in other studies in humans 19 and in cattle, 19 Other species of Tunga should also be considered, such as T. trimamillata, since it is the only species, along with T penetrans, that also parasitizes primates; however, so far, it has only been described in humans. 5 Moreover, T penetrans is a smaller flea (6 × 5 × 4 mm) when compared to T trimamillata, 5 which is in accordance with the measures in the present study.…”

“…Microscopically, the presence of the head, exoskeleton, hypodermal layer, striated muscles, tracheal rings, digestive tract, female reproductive tract, and developing eggs, as observed in the southern brown howler monkey 2, are histological features of T penetrans infestation in humans 16,17,18 and in cattle. 19 Some structures, such as the exoskeleton, hypodermal layer, tracheae, digestive tract, and developing eggs, are more frequently found than the striated muscles and the head in human biopsies. 16 This was also observed in this study, possibly related to the histological incidence of the cut surface of the parasite.…”