Human Vaccinia virus and Pseudocowpox virus co-infection: clinical description and phylogenetic characterization.

BACKGROUND: Occupational exanthematic diseases represent an important cause of public health impact and economical losses. Among the viral exanthematic diseases, two caused by poxviruses are noteworthy: the bovine vaccinia (BV), caused by the Vaccinia virus (VACV); and the milker's nodule, in which the agent is the Pseudocowpox virus (PCPV). Both agents are zoonotic and have been associated with several cases of bovine infection. In Brazilian rural areas BV has been highly prevalent, particularly in milk herds. Farmers, milkers and their close contacts developed lesions on the hands, forearms, legs and face accompanied by several systemic symptoms. Although VACV and PCPV present with similar epidemiological and transmission patterns, no VACV and PCPV co-infection cases have to date been described. OBJECTIVES: To describe the first case of zoonotic VACV and PCVP co-infection, based on serological and molecular methods. STUDY DESIGN AND RESULTS: In this work we report a case of a Brazilian rural worker who presented with a large severely ulcerated-pustule skin lesion, associated with fever, headache, malaise, myalgia and axillary, inguinal and cervical limphadenopathy. The worker declared occupational contact with cattle that had notable injuries on their teats. Human and bovine clinical samples were collected and submitted to serological and molecular tests. PCR and phylogenetic analysis revealed the presence of VACV DNA and PCPV DNA in the patient's lesion. Serological tests indicated anti-VACV neutralizing antibodies and molecular assays showed the presence of VACV and PCPV DNA in the patient sera. VACV and PCPV also were detected in dairy cattle. CONCLUSION: Together, these results indicate a case of zoonotic VACV/PCPV co-infection. Epidemiological surveillance and appropriate medical treatment are essential for the control of both diseases, especially in the most severe cases, as described in the present study.