Zika in Yap

Special Report

By Stan Deresinski, MD, FACP, Clinical Professor of Medicine, Stanford, Associate Chief of Infectious Diseases, Santa Clara Valley Medical Center, is Editor for Infectious Disease Alert.

Source: www.cdc.gov

Synopsis: An outbreak of mild dengue-like illness on the Pacific island of Yap was due to a flavivirus, the Zika virus.

An outbreak of dengue-like illness that began in May, 2007, on Yap, one of the Carolina islands of the Federated States of Micronesia, proved to be due to Zika virus. As of early August, 99 confirmed and 54 probable cases had been identified, with the most recent case dating from July 17th. Additional probable cases have been seen on neighboring islands. The cause of the outbreak was determined by the Arbovirus Diagnostic Laboratory of the CDC.

The Yap Islands

Dengue is a mosquito-borne flavivirus first identified in 1947 in a sentinel rhesus monkey stationed on a tree platform in the Zika forest, near Entebbe, Uganda and monkeys are presumed to be the natural reservoir of the virus. Symptoms and signs are generally relatively mild and consist of fever, conjunctivitis, arthralgias, and maculopapular rash. The illness lasts 2 to 7 days. Treatment is symptomatic. Serosurveys indicate that Zika virus infections occur in Africa, Southeast Asia, and Malaysia. For instance, a seroprevalence study found an incidence of 31% in several communities in the Nigerian state of Oyo between 1971 and 1975.1 In addition, an outbreak occurred in Indonesia almost 3 decades ago.

With the assistance of 2 Epidemiologic Service Officers of the CDC, control measures are aimed at reducing peridomestic mosquito breeding sites in open water containers, aerial spraying, and personal protective measures aimed at prevention of mosquito bites.2


  1. Fagbami AH. Zika virus infections in Nigeria: virological and seroepidemiological investigations in Oyo State. J Hyg 1979; 83:213-219.
  2. www.cdc.gov