eMedicine Specialties > Infectious Diseases > Viral Infections

Poxviruses: Differential Diagnoses & Workup

Author: John D Shanley, MD, MPH, Professor Emeritus, University of Connecticut; Professor of Preventive Medicine, Stony Brook Medical Center
Contributor Information and Disclosures

Updated: Aug 26, 2008

Differential Diagnoses

Anthrax
Meningococcemia
Bacillary Angiomatosis
Molluscum Contagiosum
Coxsackieviruses
Vaccinia
Hand-Foot-and-Mouth Disease
Varicella-Zoster Virus
Herpes Simplex
Herpes Zoster
Impetigo

Other Problems to Be Considered

Chickenpox
North American blastomycosis
Varicella

Workup

Laboratory Studies

  • Most poxvirus infections can be recognized clinically. The virions can be recognized with negative staining and electron microscopy.
  • Variola and vaccinia can be cultured in vitro on chorioallantoic membranes of eggs and in tissue culture. In suspected cases of smallpox, the public health authorities should be notified immediately and clinical samples processed in containment facilities.
  • Infections with poxviruses induce humoral responses that include hemagglutination inhibition (HI), complement fixing (CF), and neutralizing antibodies. In vaccinia cases, the HI, CF, and antibody titers decline over time.

Other Tests

  • Histological analysis of the nodular skin lesions can be performed.

Histologic Findings

The cutaneous lesions of smallpox begin with vascular congestion of the dermis associated with mononuclear (lymphocytes and monocytes) infiltration. Epidermal cells develop ballooning degeneration, and intraepithelial multiloculated vesicles develop by rupture of cellular membranes in the stratum spinosum. Cells develop cytoplasmic acidophilic inclusions known as Guarnieri bodies. The lesions of vaccinia and monkeypox follow a similar evolution.

The lesion of molluscum contagiosum consists of a localized area of hypertrophic and hyperplastic epidermis that extends down to the dermis and produces a nodule that rises above the skin. Individual epidermal cells are enlarged and contain a characteristic cytoplasmic inclusion of hyaline acidophilic material called a molluscum body. The center of the lesion consists of degenerating epidermal cells and keratin. Very little inflammation is present.

More on Poxviruses

Overview: Poxviruses
Differential Diagnoses & Workup: Poxviruses
Treatment & Medication: Poxviruses
Follow-up: Poxviruses
Multimedia: Poxviruses
References

References

  1. Preston R. The Demon in the Freezer. In: The New Yorker. July 12, 1999:44-61. [Full Text].

  2. Kile JC, Fleischauer AT, Beard B, et al. Transmission of monkeypox among persons exposed to infected prairie dogs in Indiana in 2003. Arch Pediatr Adolesc Med. Nov 2005;159(11):1022-5. [Medline].

  3. De Clercq E, Neyts J. Therapeutic potential of nucleoside/nucleotide analogues against poxvirus infections. Rev Med Virol. Sep-Oct 2004;14(5):289-300. [Medline].

  4. Meadows KP, Tyring SK, Pavia AT, et al. Resolution of recalcitrant molluscum contagiosum virus lesions in human immunodeficiency virus-infected patients treated with cidofovir. Arch Dermatol. Aug 1997;133(8):987-90. [Medline].

  5. Ibarra V, Blanco JR, Oteo JA, et al. Efficacy of cidofovir in the treatment of recalcitrant molluscum contagiosum in an AIDS patient. Acta Derm Venereol. Jul-Aug 2000;80(4):315-6. [Medline].

  6. Geerinck K, Lukito G, Snoeck R, et al. A case of human orf in an immunocompromised patient treated successfully with cidofovir cream. J Med Virol. Aug 2001;64(4):543-9. [Medline].

  7. Baxby D, Bennett M. Poxvirus zoonoses. J Med Microbiol. Jan 1997;46(1):17-20, 28-33. [Medline].

  8. Di Giulio DB, Eckburg PB. Human monkeypox: an emerging zoonosis. Lancet Infect Dis. Jan 2004;4(1):15-25. [Medline].

  9. Fenner F. Adventures with poxviruses of vertebrates. FEMS Microbiol Rev. Apr 2000;24(2):123-33. [Medline].

  10. Fenner F. Poxviruses. In: Richman D, Whitley RJ, Hayden FG, eds. Clinical Virology. ed. New York, NY: Churchill Livingstone; 1996:357-74.

  11. Fenner F, Henderson DH, Arita I, et al. Smallpox and its eradication. Geneva, Switzerland: World Health Organization.; 1988.

  12. Henderson DA, Inglesby TV, Bartlett JG, et al. Smallpox as a biological weapon: medical and public health management. Working Group on Civilian Biodefense. JAMA. Jun 9 1999;281(22):2127-37. [Medline].

  13. Henderson DH, Moss B. Smallpox and vaccinia. In: Plotkin S, Orenstein WA, eds. Vaccines. 3rd. Philadelphia, Pa: WB Saunders; 1999:74-97.

  14. Lewis-Jones S. Zoonotic poxvirus infections in humans. Curr Opin Infect Dis. Apr 2004;17(2):81-9. [Medline].

  15. Perna AG, Tyring SK. A review of the dermatologic manifestations of poxvirus infections. Dermatol Clin. Apr 2002;20(2):343-6. [Medline].

  16. Slifka MK, Hanifin JM. Smallpox: the basics. Dermatol Clin. Jul 2004;22(3):263-74, vi. [Medline].

Further Reading

Keywords

poxviruses, pox virus, orthopoxviruses, parapoxviruses, smallpox, variola major, variola minor, flat smallpox, hemorrhagic variola, vaccinia, monkeypox, orf, contagious pustular dermatitis, contagious ecthyma, pseudocowpox, milker's nodule, molluscum contagiosum, Poxviridae, bovine papular stomatitis virus, pseudocowpox virus, sealpox virus, yatapoxviruses, yatapoxvirus, tanapox virus, yabapoxviruses, yabapoxvirus, buffalopox, cantagalo, aracatuba, deerpox virus

Contributor Information and Disclosures

Author

John D Shanley, MD, MPH, Professor Emeritus, University of Connecticut; Professor of Preventive Medicine, Stony Brook Medical Center
John D Shanley, MD, MPH is a member of the following medical societies: American Association for the Advancement of Science, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

Medical Editor

Larry I Lutwick, MD, Professor of Medicine, State University of New York, Downstate Medical School; Director, Infectious Diseases, Veterans Affairs New York Harbor Health Care System, Brooklyn Campus
Larry I Lutwick, MD is a member of the following medical societies: American College of Physicians and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Charles V Sanders, MD, Edgar Hull Professor and Chairman, Department of Internal Medicine, Professor of Microbiology, Immunology and Parasitology, Louisiana State University School of Medicine at New Orleans; Medical Director, Medicine Hospital Center, Charity Hospital and Medical Center of Louisiana at New Orleans; Consulting Staff, Ochsner Medical Center
Charles V Sanders, MD is a member of the following medical societies: Alliance for the Prudent Use of Antibiotics, Alpha Omega Alpha, American Association for the Advancement of Science, American Association of University Professors, American Clinical and Climatological Association, American College of Physician Executives, American College of Physicians, American Federation for Medical Research, American Foundation for AIDS Research, American Geriatrics Society, American Lung Association, American Medical Association, American Society for Microbiology, American Thoracic Society, American Venereal Disease Association, Association for Professionals in Infection Control and Epidemiology, Association of American Medical Colleges, Association of American Physicians, Association of Professors of Medicine, Infectious Disease Society for Obstetrics and Gynecology, Infectious Diseases Society of America, Louisiana State Medical Society, Orleans Parish Medical Society, Royal Society of Medicine, Sigma Xi, Society of General Internal Medicine, Southeastern Clinical Club, Southern Medical Association, Southern Society for Clinical Investigation, and Southwestern Association of Clinical Microbiology
Disclosure: Nothing to disclose.

CME Editor

Eleftherios Mylonakis, MD, Clinical and Research Fellow, Department of Internal Medicine, Division of Infectious Diseases, Massachusetts General Hospital
Eleftherios Mylonakis, MD is a member of the following medical societies: American Association for the Advancement of Science, American College of Physicians, American Society for Microbiology, and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

Chief Editor

Burke A Cunha, MD, Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital
Burke A Cunha, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

 
 
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