Human Cowpox Infection Clinical Presentation
- Author: Nikki A Levin, MD, PhD; Chief Editor: Dirk M Elston, MD more...
Generally, patients are young; 50% of patients are younger than 18 years. Most cases occur in late summer to fall. Cases present in endemic areas of Europe.
Usually, only 1 or a small number of lesions occur on the hands (48%) and face (33%). Patients may report having a flat red lesion that became raised and then blistered over a period of 2 weeks. The blister subsequently became crusted, with the surrounding skin becoming red and swollen. The lesions are characteristically described as quite painful.
Patients may have eye complaints. Patients may report fever, malaise, lethargy, vomiting, and sore throat, which usually lasts 3-10 days but resolves during the eschar stage of cutaneous lesions.
Physical findings generally are limited to the skin, eyes, and lymph nodes. Cutaneous findings develop as follows:
Days 1-6 (after inoculation): An inflamed macule appears at the site of contact with the infected animal and at any secondary sites of accidental transfer.
Days 7-12: The inflamed lesion becomes papular, then vesicular.
Days 13-20: The vesicle becomes hemorrhagic, then pustular, and has a tendency to ulcerate, with surrounding edema and induration. Secondary lesions may form nearby.
Rarely, the cutaneous lesions may become generalized before resolving. Ocular findings include conjunctivitis, periorbital edema, and corneal involvement. Enlarged painful local lymph nodes often are observed. Necrotizing lymphadenitis has been reported.
The natural reservoir of cowpox virus is believed to be small woodland mammals, such as bank voles and wood mice, with humans, cows, and cats being only accidental hosts.
Risk factors for infection with cowpox include exposure to potentially infected animals (eg, cats, cows, rodents) in an endemic area. Risk factors for dissemination of infection include atopic dermatitis and use of systemic corticosteroids.
Esposito, JJ, Fenner F. Poxviruses. Knipe D, Howley PM, Griffin DE, Lamb RA, Martin MA, Roizman B, Straus SE, eds. Fields Virology. 4th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2001. Chapter 85.
Burton JL. Of mice and milkmaids, cats and cowpox. Lancet. 1994 Jan 8. 343(8889):67. [Medline].
Baxby D, Bennett M, Getty B. Human cowpox 1969-93: a review based on 54 cases. Br J Dermatol. 1994 Nov. 131(5):598-607. [Medline].
Pelkonen PM, Tarvainen K, Hynninen A, et al. Cowpox with severe generalized eruption, Finland. Emerg Infect Dis. 2003 Nov. 9(11):1458-61. [Medline].
Honlinger B, Huemer HP, Romani N, Czerny CP, Eisendle K, Hopfl R. Generalized cowpox infection probably transmitted from a rat. Br J Dermatol. 2005 Aug. 153(2):451-3. [Medline].
Moss B, Shisler JL. Immunology 101 at poxvirus U: immune evasion genes. Semin Immunol. 2001 Feb. 13(1):59-66. [Medline].
Dasgupta A, Hammarlund E, Slifka MK, Fruh K. Cowpox virus evades CTL recognition and inhibits the intracellular transport of MHC class I molecules. J Immunol. 2007 Feb 1. 178(3):1654-61. [Medline].
Byun M, Wang X, Pak M, Hansen TH, Yokoyama WM. Cowpox virus exploits the endoplasmic reticulum retention pathway to inhibit MHC class I transport to the cell surface. Cell Host Microbe. 2007 Nov 15. 2(5):306-15. [Medline].
Amer M, El-Gharib I, Rashed A, Farag F, Emara M. Human cowpox infection in Sharkia Governorate, Egypt. Int J Dermatol. 2001 Jan. 40(1):14-7. [Medline].
Stolz W, Gotz A, Thomas P, et al. Characteristic but unfamiliar--the cowpox infection, transmitted by a domestic cat. Dermatology. 1996. 193(2):140-3. [Medline].
Postma BH, Diepersloot RJ, Niessen GJ, Droog RP. Cowpox-virus-like infection associated with rat bite. Lancet. 1991 Mar 23. 337(8743):733-4. [Medline].
Vestey JP, Yirrell DL, Aldridge RD. Cowpox/catpox infection. Br J Dermatol. 1991 Jan. 124(1):74-8. [Medline].
Vestey JP, Yirrell DL, Norval M. What is human catpox/cowpox infection?. Int J Dermatol. 1991 Oct. 30(10):696-8. [Medline].
Wolfs TF, Wagenaar JA, Niesters HG, Osterhaus AD. Rat-to-human transmission of Cowpox infection. Emerg Infect Dis. 2002 Dec. 8(12):1495-6. [Medline].
Kurth A, Wibbelt G, Gerber HP, Petschaelis A, Pauli G, Nitsche A. Rat-to-elephant-to-human transmission of cowpox virus. Emerg Infect Dis. 2008 Apr. 14(4):670-1. [Medline].
Lewis-Jones MS, Baxby D, Cefai C, Hart CA. Cowpox can mimic anthrax. Br J Dermatol. 1993 Nov. 129(5):625-7. [Medline].
Rajan N, Carmichael AJ, McCarron BM. Human cowpox: presentation and investigation in an era of bioterrorism. J Infect. 2005 Oct. 51(3):e167-9. [Medline].
Pahlitzsch R, Hammarin AL, Widell A. A case of facial cellulitis and necrotizing lymphadenitis due to cowpox virus infection. Clin Infect Dis. 2006 Sep 15. 43(6):737-42. [Medline].
Schupp P, Pfeffer M, Meyer H, Burck G, Kolmel K, Neumann C. Cowpox virus in a 12-year-old boy: rapid identification by an orthopoxvirus-specific polymerase chain reaction. Br J Dermatol. 2001 Jul. 145(1):146-50. [Medline].
Smee DF, Bailey KW, Sidwell RW. Comparative effects of cidofovir and cyclic HPMPC on lethal cowpox and vaccinia virus respiratory infections in mice. Chemotherapy. 2003 Jun. 49(3):126-31. [Medline].
Quenelle DC, Collins DJ, Kern ER. Cutaneous infections of mice with vaccinia or cowpox viruses and efficacy of cidofovir. Antiviral Res. 2004 Jul. 63(1):33-40. [Medline].
Kesson AM, Ferguson JK, Rawlinson WD, Cunningham AL. Progressive vaccinia treated with ribavirin and vaccinia immune globulin. Clin Infect Dis. 1997 Oct. 25(4):911-4. [Medline].
Thornburg NJ, Ray CA, Collier ML, Liao HX, Pickup DJ, Johnston RE. Vaccination with Venezuelan equine encephalitis replicons encoding cowpox virus structural proteins protects mice from intranasal cowpox virus challenge. Virology. 2007 Jun 5. 362(2):441-52. [Medline].
Lee WC, Manjaly G, Skinner DW, O'Neill PM. Cowpox infection of the nose. J Laryngol Otol. 1996 Aug. 110(8):782-4. [Medline].
Haase O, Moser A, Rose C, Kurth A, Zillikens D, Schmidt E. Generalized cowpox infection in a patient with Darier disease. Br J Dermatol. 2011 May. 164(5):1116-8. [Medline].
Blackford S, Roberts DL, Thomas PD. Cowpox infection causing a generalized eruption in a patient with atopic dermatitis. Br J Dermatol. 1993 Nov. 129(5):628-9. [Medline].