Potential Sexual Transmission of Zika Virus
Didier Musso, Claudine Roche, Emilie Robin, Tuxuan Nhan, Anita Teissier, Van-Mai Cao-Lormeau
In December 2013, during a Zika virus (ZIKV) outbreak in
French Polynesia, a patient in Tahiti sought treatment for
hematospermia, and ZIKV was isolated from his semen.
ZIKV transmission by sexual intercourse has been previously suspected. This observation supports the possibility
that ZIKV could be transmitted sexually.
Z
ika virus (ZIKV) is a mosquitoborne arbovirus in the
family Flaviviridae, genus Flavivirus. It was irst isolated in 1947 from a rhesus monkey in the Zika forest of
Uganda (1). Sporadic human cases were reported from the
1960s in Asia and Africa. The irst reported large outbreak
occurred in 2007 on Yap Island, Federated States of Micronesia (2). The largest known ZIKV outbreak reported started in October 2013 in French Polynesia, South Paciic (3),
a territory of France comprising 67 inhabited islands; an
estimated 28,000 persons (11% of the population) sought
medical care for the illness (4). The most common symptoms of Zika fever are rash, fever, arthralgia, and conjunctivitis. Most of the patients had mild disease, but severe neurologic complications have been described in other patients
in French Polynesia (5).
The Study
In early December 2013, during the ZIKV outbreak, a
44-year-old man in Tahiti had symptoms of ZIKV infection: asthenia, low grade fever (temperature from 37.5°C to
38°C) and arthralgia. Symptoms lasted 3 days. Eight weeks
later, he described a second episode of symptoms compatible with ZIKV infection: temperature from 37.5°C to 38°C,
headache on days 1–3, and wrist arthralgia on days 5–7.
The patient did not seek treatment, thus biological samples
were not collected during the irst 2 periods of illness. The
patient fully recovered from the second episode, but 2
weeks later he noted signs of hematospermia and sought
treatment. Because the patient had experienced symptoms
of ZIKV infection some weeks before, he was referred to
our laboratory in the Institut Louis Malardé, Papeete, Tahiti for ZIKV infection diagnostic testing. The medical
questionnaire revealed no signs of urinary tract infection,
prostatitis, urethritis, or cystitis, and the patient stated that
he did not had any recent physical contact with persons
who had acute ZIKV infection. We collected blood and semen samples. Direct and macroscopic examinations of the
Author afiliation: Institut Louis Malardé, Papeete, Tahiti, French
Polynesia
DOI: http://dx.doi.org/10.3201/eid2102.141363
semen conirmed hematospermia. We extracted RNA using the NucliSENS easyMAG system (bioMérieux, Marcy
l’Etoile, France) from 200 μL of blood and from 500 μL
of semen and urine; both were eluted by 50 μL of elution
buffer. We used 5 μL of RNA extracted for ampliication.
We tested blood and semen RNA extracts using real-time
reverse transcription PCR (rRT-PCR) as described using
2 primers/probe ampliication sets speciic for ZIKV (3).
The rRT-PCR results were positive for ZIKV in semen
and negative in blood, and conirmed by sequencing of
the genomic position 858–1138 encompassing the prM/E
protein coding regions of ZIKV. The generated sequence
(GenBank accession no. KM014700) was identical to those
previously reported at the beginning of the ZIKV outbreak
(3). Three days later, we collected a urine sample, then a
second set of blood and semen samples. Semen and urine
from this second collection were not found to contain traces of blood by both direct and macroscopic examinations.
rRT-PCR detected ZIKV RNA in the semen and urine, but
not in the blood sample.
We quantiied ZIKV RNA loads using an RNA synthetic transcript standard that covers the region targeted
by the 2 primers/probe sets. RNA loads were: 2.9 × 107
copies/mL and 1.1 × 107 copies/mL in the irst and second
semen samples, respectively, and 3.8 × 103 copies/mL in
the urine sample.
We cultured semen and urine as described for dengue virus cultured from urine (6). Briely, 200 μL of each
sample diluted in 200 μL of 1% fetal calf serum (FCS)
minimum essential medium (MEM) were inoculated
onto Vero cells and incubated for 1 h at 37°C; inoculum
was then removed and replaced by 1 mL of culture medium. We also inoculated a negative control (200 μL of
1% FCS-MEM) and a positive control (5 μL of a ZIKVpositive serum diluted in 200 μL of 1% FCS-MEM). The
cells were then incubated at 37°C in 5% CO2 for 6 days.
The presence of ZIKV in the culture luids was detected
by rRT-PCR as described.
Replicative ZIKV particles were found in the 2 semen
samples but none were detected in the urine sample. This
inding does not exclude the possibility that ZIKV particles
were present in urine. Positive samples were not titered.
Conclusions
The ZIKV natural transmission cycle involves mosquitoes,
especially Aedes spp. (7), but perinatal transmission (8)
and potential risk for transfusion-transmitted ZIKV infections has also been demonstrated (9). Moreover, ZIKV
Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 21, No. 2, February 2015
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DISPATCHES
transmission by sexual intercourse has been suggested by
Foy et al. (10), who described a patient who was infected
with ZIKV in southeastern Senegal in 2008. After returning to his home in Colorado, United States, he experienced
common symptoms of ZIKV infection and symptoms of
prostatitis. Four days later, he observed signs of hematospermia, and on the same day, his wife had symptoms of
ZIKV infection. Because the wife of the patient had not
traveled out of the United States during the previous year
and had sexual intercourse with him 1 day after he returned
home, transmission by semen was suggested. ZIKV infection of the patient and his wife was conirmed by serologic
testing, but the presence of ZIKV in the semen of the patient was not investigated.
Infectious organisms, especially sexually transmitted
microorganisms including viruses (human papillomavirus
or herpes simplex virus), are known to be etiologic agents
of hematospermia (11). To our knowledge, before the report of Foy et al. (10) and this study, arbovirus infections in
humans had not been reported to be associated with hematospermia, and no arboviruses had been isolated from human semen.
We detected a high ZIKV RNA load and replicative
ZIKV in semen samples, but ZIKV remained undetectable by rRT-PCR in the blood sample collected at the same
time. These results suggest that viral replication may have
occurred in the genital tract, but we do not know when this
replication started and how long it lasted. The fact that the
patient had no common symptoms of ZIKV acute infection
concomitantly to hematospermia suggests that the viremic
phase occurred upstream, probably during the irst or second episode of mild fever, headache, and arthralgia.
The detection of ZIKV in both urine and semen is consistent with the results obtained in a study of effects of Japanese encephalitis virus, another lavivirus, on boars. The
virus was isolated from urine and semen of experimentally
infected animals, and viremia developed in female boars
that artiicially inseminated with the infectious semen (12).
Flaviviruses have also been detected in urine of persons infected with West Nile virus (WNV). WNV RNA
was detected in urine for a longer time and with higher
RNA load than in plasma (13). WNV antigens were detected in renal tubular epithelial cells, vascular endothelial
cells, and macrophages of kidneys from infected hamsters
(14), suggesting that persistent shedding of WNV in urine
was caused by viral replication in renal tissue. Dengue virus (DENV) RNA and DENV nonstructural protein 1 antigen were also detected in urine samples for a longer time
than in blood, but infectious DENV has not been isolated
in culture. Hirayama et al. concluded that the detection of
DENV by rRT-PCR was useful to conirm DENV infections after the viremic phase (6). Also, yellow fever virus
RNA was isolated from the urine of vaccinated persons
360
(15), and Saint Louis encephalitis viral antigens, but not
infective virus, have been detected in urine samples from
infected patients (10).
Our indings support the hypothesis that ZIKV can be
transmitted by sexual intercourse. Furthermore, the observation that ZIKV RNA was detectable in urine after viremia
clearance in blood suggests that, as found for DENV and
WNV infections, urine samples can yield evidence ofZIKV
for late diagnosis, but more investigation is needed.
We obtained written informed consent from the patient for
publication of this report, and publication of data related to
ZIKV infections have been approved by the Ethics Committee of
French Polynesia under reference 66/CEPF.
Dr. Musso is a medical doctor and director of the Diagnosis
Medical Laboratory and the Unit of Emerging Infectious Diseases of the Institut Louis Malardé, Papeete, Tahiti, French Polynesia. His research programs target endemic infectious diseases,
especially arbovirus infections, leptospirosis, tuberculosis, and
lymphatic ilariasis.
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Address for correspondence: Didier Musso, Institut Louis Malardé, PO
Box 30, 98713 Papeete, Tahiti, French Polynesia; email:
[email protected]
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