Investigation and analysis of a human orf outbreak among people living on the same farm

Human orf is a viral zoonotic infection caused by Parapoxvirus. The skin lesions of human orf can be misdiagnosed as cutaneous anthrax leading to overtreatment and also fear. This study was conducted to analyze an outbreak which led to deaths among kids and lambs in the same flock, and skin lesions in some persons who were living on the same farm that were initially diagnosed as cutaneous anthrax by a practitioner. Eight patients with skin lesions and eleven persons who had no skin lesion were considered as patients and control groups, respectively. The cultures obtained from the lesions of all patients were negative for Bacillus anthracis. The diagnosis of skin lesions was done by clinical findings, histopathological examination and PCR as human orf. To be under 20 years of age, direct contact with the animals, and contact with flayed skin of sick animals were the risk factors for human orf (Odds Ratio 7.5; 95% Confidence Interval 1.02-54.54, OR 12.25; 95% CI:1.3-100.9, OR 16.67; 95% CI:1.65-148.20, respectively). Orf should be kept in mind in the differential diagnosis of skin lesions resembling anthrax. For control and prevention of orf, transmission routes should be known; good hand hygiene and other personal protective measures have to be implemented.