Molluscum Contagiosum in a Horse

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

“…11,15 Both diseases are usually mild and thus have irrelevant economic impact for the herds. 10,11,17 An outbreak of severe cutaneous disease associated with orthopoxvirus infection in horses in southern Brazil was investigated in the current report. The disease affected 14 Crioulo horses in a husbandry farm located in the county of Pelotas, state of Rio Grande do Sul, Brazil, in February 2008.…”

“…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.…”

“…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.…”

“…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.…”