Could Zika be spread through SEX?
Traces of the virus are found in semen, while one scientist claims he passed it
to his wife
As the devastating Zika virus rampages through the Caribbean
and Latin America - and threatens to hit parts of the US such as Florida - more
and more questions are being asked about how it can be transmitted. The virus has been linked to birth defects in thousands of
Brazilian babies, born with heads smaller than normal and undeveloped brains.
Symptoms include a rash, fever, conjunctivitis and headache
and to date, 21 countries have been affected.
At the moment, there is clear scientific evidence the virus
is transmitted by the same type of mosquito that spreads other tropical
diseases, such as dengue fever, chikungunya and yellow fever.
But there are also fears the virus may be passed on through
sex, following two reports in medical literature. One states that Zika was found in the semen of a man from
Tahiti, the other that the virus was passed from a husband to his wife after
intercourse.
But is there really a risk?
In a statement issued this week, the World Health
Organisation said there was still insufficient evidence to make the link.
But these research papers argue otherwise
One,
published in 2011, details the story of Professor Brian Foy, who claims he
passed Zika to his wife through sex. Professor
Foy, a biologist from the University of Colorado, contracted the
virus while on a field trip to Senegal.
HOW ELSE COULD ZIKA POTENTIALLY BE TRANSMITTED? 
the World Health Organisation addressed other concerns
about how the virus may be spread. It said.
Zika can be
transmitted through blood, but this is an
infrequent mechanism.
Standard
precautions that are already in place for ensuring safe blood donations and
transfusions should be followed. There is
currently no evidence that Zika can be transmitted to babies through breast milk. Mothers in
areas with Zika should follow the WHO recommendations on breastfeeding.
This is
exclusive breastfeeding for the first 6 months, followed by continued
breastfeeding with complementary foods up to 2 years or beyond.
He
and his colleague had been collecting mosquitoes in a south-eastern
village called Bandafassi, where they were often bitten. Five days
after his return home, Professor Foy fell ill - his symptoms included extreme
tiredness, swollen wrists, rashes and painful urination.
He also had
skin problems and what appeared to be blood in his semen.
A few weeks
later his wife also developed similar symptoms, along with extreme sensitivity
to light, but their four children were unharmed. 
The
scientists were baffled as to what Mrs Foy had caught until a year later when,
on a hunch, they carried out a battery of tests and concluded that sexual
contact between the couple was the most likely cause. Professor Foy
and the co-authors of his paper, published in the journal Emerging Infectious
Diseases, believe it is the first instance of sexual transmission of a
mosquito-born virus between humans. Such a
possibility has been explored before among animals, but not in humans.
In his paper,
he added the crucial final piece to the puzzle: ‘Patients 1 and 3 (Mr and Mrs
Foy) reported having vaginal sexual intercourse in the days after patient 1
returned home but before the onset of his clinical illness.
‘My wife
wasn't happy with what happened afterwards. Then there is the case of the Tahitian patient who was found
to have the Zika virus in his semen - leading the scientists reporting his case
to conclude it can be transmitted through sex.
Writing in the journal Emerging Infectious Diseases last year, they
explained how the 44-year-old had developed symptoms of the virus during an
outbreak in French Polynesia.
These included a low-grade fever, a lack of energy and joint
pain.
Two weeks after recovering however, he noticed blood in his
semen and sought treatment.
And because he had recently experienced symptoms of Zika, he
was referred for tests at the country's Institut Louis Malardé, in Papeete. In his paper, Dr Didier Musso, director of the infectious disease
unit, explains the patient had no signs of conditions that usually cause blood
in the urine - such as a urinary tract infection or inflammation of the
prostate.
He had also not come into physical contact with anyone who
was actively suffering with the Zika virus. But further tests revealed the virus was present not only in
his semen - but also in his urine.
The latter finding, the researchers say, could also help
when diagnosing people at a late stage
Despite this, the jury is still very firmly undecided on the
issue.
In a statement issued this week, the World Health
Organisation said there was still insufficient evidence to make the link. 'The role of Aedes mosquitoes in transmitting Zika is
documented and well understood, while evidence about other transmission routes
is limited,' it said.
'Zika has been isolated in human semen, and one case of
possible person-to-person sexual transmission has been described. 'However, more evidence is needed to confirm whether sexual
contact is a means of Zika transmission.'
And Dr Márcio Nehab, a paediatrician and
infectious disease specialist at Fiocruz, a research institute in Rio
de Janeiro, stated this week that the focus was still very much
on mosquitoes.
'We still need a lot of study to conclude that sexual
transmission can happen because little is known about the Zika virus.
'At the moment, we have to care more about the known vector,
which is the mosquito, as the virus transmission route
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