Zika virus outbreak on Yap Island, Federated States of Micronesia.
BACKGROUND
In 2007, physicians on Yap Island reported an outbreak of illness characterized by rash, conjunctivitis, and arthralgia. Although serum from some patients had IgM antibody against dengue virus, the illness seemed clinically distinct from previously detected dengue. Subsequent testing with the use of consensus primers detected Zika virus RNA in the serum of the patients but no dengue virus or other arboviral RNA. No previous outbreaks and only 14 cases of Zika virus disease have been previously documented.


METHODS
We obtained serum samples from patients and interviewed patients for information on clinical signs and symptoms. Zika virus disease was confirmed by a finding of Zika virus RNA or a specific neutralizing antibody response to Zika virus in the serum. Patients with IgM antibody against Zika virus who had a potentially cross-reactive neutralizing-antibody response were classified as having probable Zika virus disease. We conducted a household survey to estimate the proportion of Yap residents with IgM antibody against Zika virus and to identify possible mosquito vectors of Zika virus.


RESULTS
We identified 49 confirmed and 59 probable cases of Zika virus disease. The patients resided in 9 of the 10 municipalities on Yap. Rash, fever, arthralgia, and conjunctivitis were common symptoms. No hospitalizations, hemorrhagic manifestations, or deaths due to Zika virus were reported. We estimated that 73% (95% confidence interval, 68 to 77) of Yap residents 3 years of age or older had been recently infected with Zika virus. Aedes hensilli was the predominant mosquito species identified.


CONCLUSIONS
This outbreak of Zika virus illness in Micronesia represents transmission of Zika virus outside Africa and Asia. Although most patients had mild illness, clinicians and public health officials should be aware of the risk of further expansion of Zika virus transmission.
Duffy
Mark R
MR
Division of Vector-Borne Infectious Diseases, National Center for Zoonotic, Vector-Borne, and Enteric Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA.
Chen
Tai-Ho
TH
Hancock
W Thane
WT
Powers
Ann M
AM
Kool
Jacob L
JL
Lanciotti
Robert S
RS
Pretrick
Moses
M
Marfel
Maria
M
Holzbauer
Stacey
S
Dubray
Christine
C
Guillaumot
Laurent
L
Griggs
Anne
A
Bel
Martin
M
Lambert
Amy J
AJ
Laven
Janeen
J
Kosoy
Olga
O
Panella
Amanda
A
Biggerstaff
Brad J
BJ
Fischer
Marc
M
Hayes
Edward B
EB
D000293:Adolescent; D000328:Adult; D000330:Aedes; D017677:Age Distribution; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D018771:Arthralgia / Q000821:virology; D002648:Child; D002675:Child, Preschool; D003236:Conjunctivitis, Viral / Q000821:virology; D003716:Dengue Virus / Q000276:immunology; D004196:Disease Outbreaks; D005076:Exanthema / Q000821:virology; D005334:Fever / Q000209:etiology; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood; D007223:Infant; D007303:Insect Vectors; D008849:Micronesia / Q000453:epidemiology; D008875:Middle Aged; D011159:Population Surveillance; D012367:RNA, Viral / Q000097:blood; D017678:Sex Distribution; D055815:Young Adult; D000071244:Zika Virus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D000071243:Zika Virus Infection / Q000150:complications / Q000453:epidemiology* / Q000821:virology
D000914:Antibodies, Viral; D007075:Immunoglobulin M; D012367:RNA, Viral