Cowpox virus infection in two brothers with possible human-to-human transmission

A Belgian student with black eschars

BACKGROUND

Human cowpox virus infection is a rare zoonotic disease. Cowpox virus is a member of the Orthopoxvirus genus, like smallpox. Over the last years records of cowpox virus transmission from pet cats and pet rats to humans in Europe have increased. This observation may result from the loss of cross-immunity against orthopoxviruses after discontinuation of routine smallpox vaccination in the 1980s.

CASE PRESENTATION

We report the first case of a human cowpox infection in an unvaccinated Belgian citizen. This 19-year-old student presented with multiple necrotic skin lesions on the chin, the scalp and the pubic region, and with cervical lymphadenopathy and flu-like symptoms. The diagnosis of human cowpox was based on electron microscopic findings and PCR examination performed on a skin biopsy of the pubic lesion. Close contact with cats (her domestic cats or cats from a local shelter) was probably the source of transmission. Spreading of the lesions was likely the result of autoinoculation. After six months all lesions spontaneously healed with atrophic scars.

DISCUSSION

To enhance awareness of this rare viral zoonosis and to verify the suspected increase in incidence and symptom severity after cessation of smallpox vaccination, one could argue whether human cowpox should become a notifiable disease.

[Facial necrosis caused by orthopoxvirus : Differential diagnosis and dermatohistopathological correlation of infectious facial ulcers]

This article reports the remarkable course of a facial ulcer in a patient receiving prednisolone for Crohn's disease. Based on the initially unclear origin of the ulcer the patient received a triple anti-infective treatment (antiviral, antibiotic, antimycotic) but the lesion showed a rapid progression. An orthopoxvirus infection could be verified later by extensive diagnostics and relevant differential diagnoses could be ruled out. Extensive necrotic changes were observed in the first weeks resulting in cicatricial healing after months. Human cowpox infections have been repeatedly reported in Germany and are a relevant zoonosis. Cats and rodents are main carriers. The differential diagnoses include infections caused by other bacterial, mycobacterial, mycotic and parasitic agents that are thoroughly discussed here both clinically and histopathologically. Especially cutaneous leishmaniasis must be named as the incidence is continuously rising. With inadequate treatment infectious facial ulcers may give rise to life-threatening complications and extensive disfiguring scarring, therefore treatment must be initiated in a timely manner.