First human cowpox infections in the Czech Republic: suspected transmission from pet rats

Human cowpox virus (CPV) infection is rare. Most cases reported in Europe have been sporadic and linked to contact with infected domestic animals, particularly cats. No human cases have previously been documented in the Czech Republic. A 22-year-old woman and her 21-year-old partner presented with vesiculopustular lesions on the shoulder, indurated erythema, and regional lymphadenopathy. Inflammatory markers were low, and initial microbiological investigations were inconclusive. Both patients were initially treated with acyclovir and doxycycline, followed by symptomatic topical treatment. The lesions evolved into deep ulcers and healed with scarring within 6–8 weeks. One patient required surgical excision of necrotic lymph nodes. Four weeks before symptom onset, the couple had purchased pet rats. Subsequently, all but one rat developed respiratory symptoms and died, raising suspicion of rat-associated cowpox. Initial Orthopoxvirus qPCR testing of the patient samples at the State Veterinary Institute was negative. Almost one year later, repeat analysis of preserved samples at the Czech National Institute of Public Health detected CPV DNA in nearly all specimens. These cases highlight the diagnostic challenges posed by CPV infection in non-endemic settings. Delayed diagnosis resulted from limited access to appropriate diagnostic testing, underscoring the need for improved laboratory diagnostics and close collaboration among clinicians, microbiologists, public health authorities, and veterinary professionals.