How big is the Zika problem?
The American Society for Reproductive Medicine (ASRM) in a Bulletin, released on February 9, 2016, succinctly noted: “at this point it seems clear that the virus has implications for reproduction, and that it can be transmitted through sexual activity and reproductive tissues.” The Bulletin then continues: “We urge patients who are pregnant, who are considering becoming pregnant or those who may be involved as donors or recipients of reproductive tissues to exercise caution.”
So here is what this means for everybody who already is pregnant or is planning on pregnancy in the near future (of course, including all patients in fertility treatment): The Zika virus is not a new virus. It was already present in Africa years ago but its significance to reproduction was only recently recognized, when Brazilian physicians noted a remarkable increase in neonates born with microcephaly (small head circumference). In trying to determine what may be the cause, investigators stumbled on the Zika virus.
It is important to note that, as of this moment, the association between the virus and microcephaly is just that: an association. This means that there is considerable reason to believe that the virus is causing the microcephaly but there is no direct proof, and how the virus may cause this very significant birth defect is not understood. It, for example, is entirely plausible that a co-factor of the virus rather than the virus itself (which could be anything, including, for example, a pesticide used against he mosquito that transmits the virus) is the real villain. Since they also identified specific eye pathologies in newborns directly attributable to the virus, and for other reasons, Brazilian investigators in recent days appear increasingly convinced that the virus, indeed, is the primary culprit.
What are the infection risks?
The Zika virus, in principle, like a good number of other viruses, is transmitted to humans through mosquito bites. Getting bitten by an infected mosquito makes such an infection likely in both sexes. There is, however, now also considerable evidence that the infection can be transmitted through sexual intercourse from men to women. Transmission from women to men has, so far, not been reported but has to be considered a possibility, as viral transmission during intercourse is usually more pronounced from men to women than women to men (see also, for example, the HIV literature).
Not all mosquitoes transmit this virus. Transmission is restricted to only two Aedes species, A. aegypti and A. albopictus, both of which also are the carriers of dengue and chikungunya viruses. Dengue fever has in recent years increased in the U.S. but is not endemic in most of the country as it is in parts of Mexico and the Caribbean. It, therefore, is unlikely that Zika virus infections will become endemic in the continental U.S. in the near future. Consequently, pregnant women or those planning to conceive in the continental U.S. really do not have to worry about being infected by this virus, unless they or their sexual partners travel to areas where the virus is endemic.
The Centers for Disease Control and Prevention (CDC), therefore, issued the so-called “Level 2 Practice Enhanced Precautions,” urging pregnant women and those seeking to become pregnant “to avoid travel to endemic areas or use enhanced prevention and follow up activity if such travel cannot be avoided.”
It is now clear that the Zika virus can be transmitted via semen. Any suspicion that a male may be infected, therefore, warrants condom uses with intercourse throughout pregnancy and, of course, interrupts potential conception attempts (for more detail, see below). For how long semen remains infected is currently still unknown. Virus has also been found in saliva and urine. Whether the virus can be transmitted through kissing is also unknown as of this point.
Diagnosis of Zika infection
One of the difficulties in diagnosing a Zika infection is that only one out of every four infected patients becomes symptomatic. In other words, women as well as their sexual partners may be infected without knowing. Diagnosis of infection is further hampered by the fact that diagnostic blood tests for the virus are currently not widely available. New York State offers Zika testing for pregnant women but the test can, as of yet, not be ordered as a routine test from commercial laboratories.
Infected patients, in addition, often complain about rather non-specific symptoms, like fever, rashes, joint and muscle pains and red eyes, often accompanied by pain in the back of eyes. Symptoms are accompanied by fatigue, chills, loss of appetite and/or sweating. It may also be accompanied by vomiting. The virus has also been associated with so-called Guillain-Barre syndrome, which presents with paralysis of one side of the face but also can lead to more severe paralyses, and is widely considered an immune response to the virus which temporarily paralyzes nerve functions. This syndrome can be associated with a variety of viral infections, including common colds.
How Zika affects fertility treatments
None of the federal agencies, nor the New York State Department of Health have specifically commented on how fertility treatments may be affected by the Zika virus. This, however, does not mean that we, here at CHR, have not carefully reviewed how spread of the virus may affect our patients and clinical practice. Here is a brief summary of the conclusions we reached as of this point. We predict they are similar to federal and State of New York recommendations that will be published in the future:
- In absence of travel to Zika-endemic areas, the risk for infection appears minimal. We, therefore, advise CHR patients to avoid such areas (this recommendation applies to both partners).
- If any CHR patient (female or male) suspects a possible Zika infection, patients should immediately inform their CHR physicians.
- Before starting a treatment cycle, our staff will verify that neither partner has traveled in the preceding month to Zika-endemic areas.
- Since it appears that the virus can be transmitted via tissue, gamete donations will receive special attention at CHR going forward, even though to our best knowledge there has never been a viral transmission via donated eggs.
- Travel information to endemic Zika areas will be included into each oocyte donor candidate interview. Candidates who traveled to an endemic area within 30 days will be disqualified from donation.
- Prior to initiation of every donor recipient cycle, the oocyte donor will again be queried about travel to endemic areas. Any travel to endemic areas within 30 days from donation will be considered cause for cycle cancellation before start.
- Since anonymous sperm donors are subject to 6-months quarantine, donor sperm from reputable sperm banks, currently, does not appear to represent risk.
Once state or federal authorities publish formal Zika guidelines or should new information become available, we, of course, will adjust CHR’s policies.
Since the virus is considered a worldwide threat to public health, considerable research efforts have been activated. As little as is currently known about this virus, we, therefore, can expect rapid clarifications on many issues in coming weeks and months. In parallel, a major effort is underway to develop a vaccine against the virus but, considering how long the testing of new vaccines takes, commercial availability of such a vaccine appears still years away. As important new knowledge is developed, we, of course, will keep our readers informed.
Summary & conclusions
In conclusion, there is currently really little reason to worry. Those who live in areas of the U.S. where in recent years an uptick in cases of Dengue fever has occurred may be at a little higher risks than the rest of the continental U.S., because Dengue suggests that the mosquito carrier for Zika is present. Elsewhere, just relax; Zika in the U.S. currently is not a catastrophic new epidemic and, despite the many uncertainties still surrounding this virus, very likely never will be. If you live in Brazil (or if you plan on visiting there for the Summer Olympics), it may be a different story, though!