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ZIKA VIRUS INFECTION
Zika virus is a member of the Flaviviridae family that was initially identified in 1947 in Uganda. It can be transmitted by Aedes aegypti and A. albopictus mosquitoes, through sexual contact, via blood transfusions, and from mother to fetus. Large Zika virus outbreaks began in 2007 in Micronesia, with subsequent transmissions in other Pacific Islands, Central and South America, Caribbean islands, Mexico, Florida, and Texas; however, since 2018 there have been no reports of Zika virus infections acquired in the US.
In 2016, Zika infection during pregnancy was linked to risk of fetal microcephaly. Approximately 20% of Zika viral infections are symptomatic, with manifestations including fever, arthralgias/arthritis, headache, and conjunctivitis. A morbilliform or scarlatiniform exanthem typically begins on the face and spreads to the trunk and extremities; follicular accentuation and palmar involvement have been described. Zika-related GuillainโBarrรฉ syndrome has also been reported. Diagnosis can be confirmed by RT-PCR-based testing of serum or urine as well as serology. Vaccine development is ongoing.
Multiple pearly, umbilicated papules in the genital area (A) and on the face (B); note the inflamed lesion on the right cheek. Inflammatory reactions are a sign of the host immune response to the virus. C Inflamed lesions surrounded by โmolluscum dermatitisโ. D, E Pustular presentations of inflamed molluscum. Culture revealed only normal skin flora. F Histologic evaluation shows numerous molluscum bodies (inset). Demonstrating these bodies in a saline preparation of expressed lesional contents serves as a technique for bedside diagnosis. BโE, Courtesy Julie V. Schaffer, MD; F, Courtesy Lorenzo Cerroni, MD.
Fig. 81.13 Molluscum contagiosum.
Table 81.6 Treatment of molluscum contagiosum. Large randomized, placebocontrolled trials showed no benefit of imiquimod. Key to evidence-based support: (1) prospective controlled trial; (2) retrospective study or large case series; (3) small case series or individual case reports.