Definition The Pathogen Among the herpesviruses, HSV-1 and HSV-2 are most closely related, with approximately 60% genomic homology. Historically, HSV-1 was more frequently associated with nongenital (especially orolabial) disease and HSV-2 with genital disease, but that distinction has become blurred…
Definition Human papillomaviruses (HPVs) are a group of small DNA viruses that cause a variety of benign and malignant lesions of the skin and mucous membranes. The most commonly recognized HPV-associated diseases include warts ( Chapter 407 ) at anogenital…
Definition Human illness caused by a poxvirus is characterized by a cutaneous manifestation; illness may be localized or systemic, depending on the particular poxvirus and the route of introduction. DNA-based assays, including polymerase chain reaction (PCR) and DNA sequencing, are…
Definition B19 parvovirus, which was discovered in the mid-1970s by electron microscopy of an anomalous precipitin reaction of a blood donor’s serum (occupying position 19 in plate B), was first linked to human disease by the observation of virus-specific immunoglobulin…
Human Polyomavirus Definition Human polyomaviruses comprise at least 14 species, denoted human polyomavirus 1 to 14, and five of these are associated with human diseases ( Table 341-1 ). Of the types of polyomaviruses that infect humans, the principal causes…
Definition Mumps is an acute viral infection characterized by inflammation of the parotid and other salivary glands. Prior to the introduction of vaccination in the United States, mumps was a common childhood illness. The incidence of mumps declined dramatically after…
Definition Although most cases of rubella infection lead to a mild viral illness, significant morbidity occurs when rubella virus infects the fetus, particularly during the first trimester of pregnancy, when it causes miscarriage and the congenital rubella syndrome in up…
Definition The term measles is applied most appropriately to “rubeola” (also known as “morbilli”), an extremely contagious, prolonged respiratory and systemic viral illness characterized by high fever, an erythematous maculopapular rash, cough, coryza, and conjunctivitis. A member of the family…
Treatment of Infected Persons General Principles The approach to treating coronavirus-2019 disease (COVID-19) must first consider the severity of the patient’s disease, which can range from mild to moderate respiratory or systemic symptoms, to severe disease (i.e., dyspnea, tachypnea, and…
Epidemiology On December 31, 2019, the World Health Organization (WHO) was informed of a cluster of cases of pneumonia of unknown cause in Wuhan City, Hubei Province, China. On January 9, 2020, a novel coronavirus (named severe acute respiratory syndrome…