Zika and sex
We still do not know a lot about the sexual transmission of the Zika virus, but it is happening and precautions are needed.
THE recent spate of reports of Zika virus (ZIKV) infections in Singapore, Thailand, and now Malaysia, have led to doctors encountering many questions from concerned patients and their families.
Answering these questions is challenging as there are still many gaps in knowledge about ZIKV infections, although its strong association with microcephaly and GuillainBarre Syndrome is generally accepted.
Although ZIKV infections are usually transmitted by mosquitoes, there are increasing reports of sexual transmission, which includes vaginal, oral and anal sex, and the sharing of sex toys.
With about 80% of those infected by ZIKV having no symptoms, sexual transmission may potentially account for more infections than previously suspected.
The first case of sexual transmission occurred in 2008.
An infected man who had recently returned from an area with active mosquitoborne ZIKV infection had sexual intercourse with a female partner at a time when he had not yet developed symptoms.
The female partner developed symptoms about a week after the sexual act.
Still much unknown
There are increasing reports of ZIKV isolated from the semen of infected men.
The virus was first isolated in the semen of an infected man in French Polynesia in 2013, about 14 days after his symptoms started.
Since then, there have been reports of detection of ZIKV in semen for 62 days (Cook Islands), 76 days (New Zealand), 93 days (France), 181 days (Italy) and 188 days (Haiti) after the onset of symptoms.
The finding of ZIKV in semen is compounded by the fact that ZIKV is also found in vaginal fluids, cervical mucus, saliva and urine of the infected.
Persistent ZIKV shedding in the saliva and urine has been found for 91 days after the onset of symptoms.
Does the persistence of viral shedding mean that those with ZIKV infection could still infect their sexual partners?
What about the infectivity of ZIKV in saliva and urine? There are no definitive answers. The likelihood of the sexual transmission of ZIKV appears to be associated with the excretion of high viral loads of ZIKV during the early phase of infection, but cases of late sexual transmission, as well as transmission between asymptomatic individuals, have also been reported.
Is there transmission with low viral loads of ZIKV?
This has not been ruled out.
International guidelines
There are many unknowns about the sexual transmission of ZIKV.
Sexual transmission can occur before, during and after symptoms develop.
It can also occur even if the infected person does not have symptoms at the time of sexual contact.
In addition, it can occur if the infected person never develops symptoms.
The interim guidance on the prevention of sexual transmission of Zika virus issued by the World Health Organization (WHO) on Sept 6 (Source: www.who.int/csr/resources/publications/ accessed on Sept 3) states:
“1. In regions with active Zika virus transmission, health programmes should ensure that:
“a. All people (male and female) with Zika virus infection and their sexual partners (particularly pregnant women) receive information about the risks of sexual transmission of Zika virus.
“b. Men and women also get counselling on safer sexual practices, and be offered condoms. The consistent use of condoms is essential to prevent sexually-transmitted infections, including human immunodeficiency virus (HIV), and unwanted pregnancy.
“c. Sexually active men and women be correctly counselled and offered a full range of contraceptive methods to be able to make an informed choice about whether and when to become pregnant, in order to prevent possible adverse pregnancy and foetal outcomes.
“d. Women who have had unprotected sex and do not wish to become pregnant due to concerns about Zika virus infection have ready access to emergency contraceptive services and counselling.
“e. Pregnant women should practice safer sex or abstain from sexual activity for at least the whole duration of the pregnancy. Their partners should also be informed about this recommendation.
“WHO does not recommend routine semen testing to detect Zika virus.
“However, symptomatic or asymptomatic men could be offered semen testing after returning from areas where transmission of Zika virus is known to occur, according to country policy.
“Two tests performed at different days (e.g. one week interval) should be performed because of false negative results or intermittent shedding.
“However, more evidence is necessary to determine the exact interval between two tests.”
Similarly, the interim guidance on the prevention of sexual transmission of ZIKV issued by the United States Centers for Disease Control and Prevention (CDC) on July 29 (Source: MMWR July 29, 2016. Vol 65, No 29, pages 745-747) states:
“Couples in which a woman is pregnant should use barrier methods against infection consistently and correctly or abstain from sex for the duration of the pregnancy.
“Couples in which a partner had confirmed Zika virus infection or clinical illness consistent with Zika virus disease should consider using barrier methods against infection consistently and correctly or abstain from sex as follows:
“l Men with Zika virus infection for at least six months after onset of illness;
“l Women with Zika virus infection for at least eight weeks after onset of illness.
“Couples in areas without active Zika transmission in which one partner travelled to or resides in an area with active Zika virus transmission, but did not develop symptoms of Zika virus disease, should consider using barrier methods against infection or abstaining from sex for at least eight weeks after that partner departed the Zikaaffected area.
“Couples who reside in an area with active Zika virus transmission might consider using barrier methods against infection or abstaining from sex while active transmission persists.”
Not going away
ZIKV infections are not going to go away. Does it matter whether transmission is imported or local? ZIKV is not just an issue of the pregnant. The role that men and unsafe sex play in the prevention of its spread cannot be ignored.
The current public health response is focused on mosquitoes.
If the spread of ZIKV is to be checked, should there not be more attention on the sexual transmission of ZIKV? Dr Milton Lum is a past president of the Federation of Private Medical Practitioners Associations and the Malaysian Medical Association. The views expressed do not represent that of organisations that the writer is associated with. The information provided is for educational and communication purposes only and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.