A key lesson of AIDS is that a virus—in HIV's case, infecting African monkeys—might pass rarely, but repeatedly, to human beings for decades before arriving in a context of epidemic potential.
Adapting to new modes of transmission and targeting novel species, the microbe can exist for thousands of years before beginning to achieve previously unimaginable feats, with devastating impact.
Now the world is facing a virus that seems poised to make a similar leap: the Zika virus.
Like HIV, Zika originated in central Africa, very rarely infecting human beings, and circulating among rainforest primates. Unlike HIV, Zika had the ability to fly, carried by Aedes aegypti mosquitoes from one monkey or human, to another.
Since reaching Brazil in 2013, where it has spread explosively over the last 12 months, Zika has demonstrated capabilities not seen, or extremely rarely noted, with any other insect-carried microbes.
Most worrying, Zika has shed its mosquito transport dependency, becoming an efficient resident of human semen
, and spread from male-to-female (and male-to-male) via sexual intercourse.
This week researchers reported
finding Zika in a woman's vagina, noting that, "the very presence in the female genital tract [implies] that sexual transmission from women to men could occur." And barely had the ink dried on that report when the U.S. Centers for Disease Control and Prevention announced today
that a woman who traveled in a Zika-hit country, who got infected through a mosquito bite, has passed the virus onto her male sexual partner in New York City, marking the first documented case of female to male sexual transmission in the U.S. (and the 14th documented sexual transmission in the U.S. overall).
If Zika finds its way into an especially sexually active community, it could well become a threat not only in America's southern, mosquito-infested states, but anywhere in the world.
Like HIV, the Zika virus would likely find its way into populations that feel discriminated against by the general population, and take its toll disproportionately among teenage girls and young women.
And while politicians play partisan games with funding on Capitol Hill, government and philanthropic donors ignore
the World Health Organization's pleas for a measly $122 million to fight it, and state health agencies
scramble to find anti-mosquito resources, the virus is spreading in new ways
, causing an ever-widening range of dangerous birth defects and human illnesses.
"I am concerned that the goose is cooked. This funding is done. It's not coming to us," Dr. Umair Shah, a public health official in Harris Country, Texas told NBC News
. "We cannot spray our way out of this situation," Shah added, saying pesticides won't be enough to stop Zika at this late date in the American South.
Recognizing the threat already unfolding in Puerto Rico, the City of New York
recently shipped one million free condoms to San Juan, where the local government put a freeze on condom prices
to combat panic-driven cost escalation and profiteering. The Brazilian government will distribute nine million free condoms in Rio during the upcoming Summer Olympics
The lingering Ebola epidemic in West Africa offers lessons on the difficulty of stopping a virus that takes on sexual transmission and can abide in semen for weeks after a man has recovered from the disease. Several times in 2015 and 2016, Ebola seemed to have been eradicated from Guinea, Sierra Leone or Liberia, only to reemerge via sexual transmission
The statistics on Zika as a sexually transmitted disease are sobering. According to the World Health Organization
, the Zika virus has emerged in 48 countries since Brazil sounded the alarm in October 2015.
Four of those countries have active mosquito-borne spread of the virus underway now, and eleven of them—including the United States—have documented sexual transmission of the virus. Two Americans have died of Zika
, one in Puerto Rico and the other in Utah. They were among the 1,132 travel-related Zika cases documented in the United States. Among the 50 states, Florida has been hardest hit
to date, with 263 confirmed cases, 43 of them pregnant women, followed by Texas.
Politics should not trump biology
"No pregnant women should have to worry that her baby will develop brain damage because she was bitten once by a mosquito," a petition to Congress
from the March of Dimes states. "It's an outrage that Congress has failed to give states and localities the resources they need to protect pregnant women and babies from Zika virus."
The Zika funding stalemate on Capitol Hill might well result in an increase in the numbers of abortions in the United States this year—an ironic and tragic outcome of a political squabble that features, among other disputes, Democrats' objection
to House Republicans' inclusion of anti-Planned Parenthood language in the GOP's Zika bill
In Latin American countries hard hit by the virus, abortion rates have soared
this year by as much as 108%, which research suggests
is due largely to women who feared carrying a "Zika baby" but had no access to tests that could confirm the healthy viability of their fetus. Such tests don't exist: American women have no special advantage in the Zika fight, despite the greater wealth of the United States.
In a few days, the Republican Party will gather for its national convention in Cleveland, Ohio—a metropolis that last year ranked in the top twenty
most mosquito-infested cities in the United States. At the end of this week, Congress will shut down for the summer, and the politicians will not return to hammer out new agreements until September 6.
Barring a remarkable compromise, the politicians will exit Washington on Friday, leaving funding for Zika prevention and research in the lurch
, with the White House, Senate, and House each offering radically different funding proposals, none of which will materialize as money for research.
Meanwhile, in all tiers of public health across America, scientists and officials are scrambling to rob other budgets in order to finance research and mosquito control measures. At local levels, this ironically means things like sexually-transmitted diseases (STDs) programs are losing money, so that counties can hire mosquito abatement experts.
At the federal level, the remaining Ebola programs
are seeing their budgets pilfered to provide temporary Zika funds, and a range of basic science research initiatives at the National Institutes of Health are on hold
, their funds diverted to efforts to understand, diagnose, treat and vaccinate against Zika.
Vital questions about Zika, especially as a sexually transmitted disease linked to birth defects, are going unanswered, thanks to the research funding gap.
- Can the world's blood supply be cleansed of Zika risk with transfusion?
- How likely is it that sexual transmission could dominate spread of Zika in the United States?
- How long can Zika survive in semen and cause infections?
- How does the virus get through the placenta to infect the developing fetus?
- Is it possible to create a 100% reliable fetal test for Zika infection and brain damage that can be used to guide decisions regarding pregnancy termination?
- Are the risks greater in a particular stage of pregnancy?
- Why aren't sonograms reliably identifying microcephaly babies in utero?
- Can a mother give birth to Zika-damaged babies if she never had symptoms of the disease?
- Are there ways that women can protect themselves and carry babies to term, short of the U.S. Centers for Disease Control and Prevention recommendation to delay pregnancies altogether?
- How can a potential Zika vaccine be safely tested on pregnant women and their babies
In the absence of answers to these and other Zika questions, women are compelled to make dire decisions, including opting for abortions
Is Zika becoming a sexually transmitted disease?
While HIV and Ebola offer potential roadmaps for how this might happen, it's still an open question. Researchers in Brazil took a deep dive
into the country's data for dengue, a virus spread by the same Aedes aegypti mosquitoes as carry Zika, analyzing of the disease's diagnoses in 2013, 2015, and early 2016.
They paid special attention to the distribution of dengue by age and gender. And they did the same for Zika cases in the country over 2015 and 2016. If all Zika cases were due to mosquito bites, the demographic distribution of dengue and Zika should match. But that's not what they found
Instead, 90% more Zika cases were registered among women, compared to the female rates for dengue.
Neighboring Colombia has also seen far more Zika in females, with young women accounting for two-thirds of the 65,726 cases diagnosed by mid-April 2016.
that though the infection rate was similar in very young children of both genders, "the incidence was significantly higher among female patients than among male patients in all other age groups."
Critics charge that both the Brazilian and Colombian studies may simply reflect the greater fear women have about exposure to Zika during pregnancy, prompting more of them to seek medical care. The researchers disagree, insisting that the higher rates of diagnosed Zika are seen in young women, whether or not they are pregnant or are trying to conceive.
One reason young women may be at higher risk is that they are having more sex with male partners whose semen may remain Zika-contaminated and infectious for months
Such a pronounced gender difference wasn't seen in the Zika outbreaks in Pacific Island nations between 1990 and 2013, but there have been subtle genetic changes
in the virus since its arrival in the Americas. Are these mutations relevant to sexual transmission? That is another research question
scientists would like to answer, if Congress ever provides funding.
At the end of June, frustrated scientists at the NIH decided
to charge ahead with pregnancy and sexual research, despite congressional gridlock, by putting numerous other disease studies on temporary hold.
A large study, tracking women over time in the United States, Puerto Rico, and Brazil, has begun enrolling volunteers. "We are going out on a limb, but we have to," Dr. Anthony Fauci, director of the NIH's Institute of Allergy and Infectious Diseases, told Reuters
. "We can't say we're going to wait until we get all the money."
When microbes gain capacity to be sexually transmitted, they rarely disappear from the human population group in which they emerged.
In 2008, for instance, physicians in San Francisco noticed that drug-resistant Staphylococcus, MRSA, was far more prevalent among gay men compared to any other demographic group; the bacterial disease had become a STD
, soon surfacing among gay men in Boston and New York.
In 2013, European researchers discovered
that a virulent form of the bacterium that causes meningitis was spreading sexually among gay men. By 2015, gay men were dying
from the new STD, and this year, public health officials all over the United States are begging gay men to get vaccinated as meningitis outbreaks
How to prevent a sexually transmitted Zika catastrophe?
So what can we do to stave off a similarly catastrophic turn of events with the Zika virus? According to the CDC
, 287 pregnant women living in the United States were diagnosed as Zika-infected by June 23, and another 250 in U.S. territories. There is no reliable test that can tell these 537 women whether or not the virus has passed to their fetus, gnawing away at their tiny, developing brains. In the United States and beyond, women especially are in desperate need of such a test.
A recent poll
conducted by the Kaiser Family Foundation found that two-thirds of Americans have heard of Zika, which means an alarming third of the population knows nothing about the disease, and is unlikely to take precautions against infection.
Fewer still—less than half—were aware that Zika could be passed sexually. In the absence of such knowledge, sexually active Americans are unlikely to use condoms.
Around the world, intriguing puzzles abound. Jacqueline Silva de Oliveira lives in Santos, Brazil, where she contracted Zika during her pregnancy—either via a mosquito or sexually, it is not known—and gave birth to twins in February.
Today, Lucas is a healthy, happy infant, but his twin sister, Laura, suffers in agonizing pain thanks to Zika microcephaly -- which slaughters brain cells and results in complete remodeling of the brain in development.
The Brazilian government is monitoring six such sets of twins
, discordant for Zika microcephaly, in hopes of learning how the virus infects (or doesn't infect) fetuses.
, a healthy couple trying to have children sought in vitro fertilization. The clinic assisting them tested their blood and his semen for various infections, including Zika: they were fine.
The couple took a holiday in the Caribbean nation of Martinique, returned to France, and underwent more tests. The man's blood was free of Zika, but about a month after they were back in France, the woman became infected. Examination of her partner's semen revealed Zika. Neither of them ever had symptoms of illness, nor felt any reason to avoid sex or use condoms, as they were a married couple trying to have a baby.
Here at home, time is running out. Researchers desperately need funding to provide the tools required to forestall a sexually transmitted Zika epidemic in the United States.
In the absence of those tools, women will make difficult choices, deferring pregnancies for months, perhaps years, and seeking abortions.
The stalemate on Capitol Hill may actually increase the likelihood that more American babies will be born with terrible malformations and neurological deficits. And, equally horribly, that hundreds, perhaps thousands, of couples will seek abortions based on suspicion of Zika infection, possibly terminating some healthy pregnancies.