Molluscum contagiosum in a horse with granulomatous enteritis

An Outbreak of Orthopoxvirus-Associated Disease in Horses in Southern Brazil

“…15,19 The most remarkable histopathological findings in the current study were somewhat similar to those observed in several equine conditions associated with different orthopoxviruses. 2,5,6,9,11,15,17,19,21 The gross findings in the outbreak reported here showed remarkable similarity to what has been described for the buccal form of horsepox, 5,6,15 with some similarity to the condition reproduced in horses by inoculation of VACV. 18 The papuloeruptive, proliferative, and exudative lesions in the muzzle, surrounding the nares and face, and in the lips and cheeks, plus the presence of large, eosinophilic, intracytoplasmic, oval or circular inclusions in vacuolated keratinocytes are considered pathognomonic of the buccal form of horsepox.…”

“…The obtained amplicon was similar in size to those obtained by amplification of CPXV (1,673 bp) and VACV (1,603 bp) genomes. 13 Although poxvirus-associated diseases have been described occasionally in horses, 2,6,7,11,12,17,21 the definitive identification of the virus species associated with the respective disease has been only rarely achieved. In fact, many clinical reports of pox disease in horses seemed to be associated with viruses of cattle or of human origin poorly characterized.…”

“…In fact, many clinical reports of pox disease in horses seemed to be associated with viruses of cattle or of human origin poorly characterized. 2,6,8,11,12,17,21 Even the epidemiology and natural history of HSPV, whose entire genome has been sequenced, 20 is rather unclear. The secular trend of poxvirus-associated diseases in horses reinforces this observation: as human and bovine poxvirus infections were being progressively controlled, and some were eventually eradicated by vaccination, the incidence of poxvirus disease in horses also progressively weaned, and the disease eventually became very rare.…”

“…7,15 Viral particles morphologically similar to the human Molluscum contagiosum virus (MOCV) have also been demonstrated by electron microscopy (EM) in the skin of horses with poxvirus-like disease. 2,11,17 The equine disease associated with MOCV is characterized by the development and persistence (up to 6 years) of elevated and waxy papules and hairless, hyperkeratotic foci (4-20 mm) on the skin of the face, neck, thorax, limbs, axillary and inguinal areas, and external genitalia. 2,11 Based on a few reports, MOCV in horses seems to be an usually mild, slow, progressive, and mildly contagious disease sharing many macroscopic and microscopic features with Uasin Gishu disease.…”

“…2,[5][6][7][8]11,12,17 In fact, horses seem to serve as alternative hosts for several human and animal pox viruses, developing different clinical syndromes upon infection with each particular virus. 14,15,19 The definitive identification of the virus species associated with the respective disease, however, has been only rarely achieved.…”