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Poxviruses Workup

  • Author: John D Shanley, MD, MPH; Chief Editor: Mark R Wallace, MD, FACP, FIDSA  more...
Updated: Oct 07, 2015

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.

Contributor Information and Disclosures

John D Shanley, MD, MPH Professor Emeritus, University of Connecticut School of Medicine; 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, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

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: American College of Physicians, Alliance for the Prudent Use of Antibiotics, The Foundation for AIDS Research, Southern Society for Clinical Investigation, Southwestern Association of Clinical Microbiology, Association of Professors of Medicine, Association for Professionals in Infection Control and Epidemiology, American Clinical and Climatological Association, Infectious Disease Society for Obstetrics and Gynecology, Orleans Parish Medical Society, Southeastern Clinical Club, American Association for the Advancement of Science, Alpha Omega Alpha, American Association of University Professors, American Association for Physician Leadership, American Federation for Medical Research, American Geriatrics Society, American Lung Association, American Medical Association, American Society for Microbiology, American Thoracic Society, American Venereal Disease Association, Association of American Medical Colleges, Association of American Physicians, Infectious Diseases Society of America, Louisiana State Medical Society, Royal Society of Medicine, Sigma Xi, Society of General Internal Medicine, Southern Medical Association

Disclosure: Received royalty from Baxter International for other.

Chief Editor

Mark R Wallace, MD, FACP, FIDSA Clinical Professor of Medicine, Florida State University College of Medicine; Clinical Professor of Medicine, University of Central Florida College of Medicine

Mark R Wallace, MD, FACP, FIDSA is a member of the following medical societies: American College of Physicians, American Medical Association, American Society for Microbiology, Infectious Diseases Society of America, International AIDS Society, Florida Infectious Diseases Society

Disclosure: Nothing to disclose.

Additional Contributors

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, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

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Poxviruses. Following vaccination for smallpox, this patient with chronic lymphocytic leukemia developed vaccinia gangrenosum.
Poxviruses. Following vaccination for smallpox, a patient with chronic lymphocytic leukemia developed vaccinia gangrenosum. The lesion was on the left shoulder. As the lesion progressed, the patient also developed evidence of dissemination. This image shows a vaccinia pustule on the foot.
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