If you've been following or even skimming the news, no doubt you've heard about the current Zika outbreak, which has been drawing comparisons to the HIV pandemic (as well as the recent Ebola epidemic). So, what is Zika, and how does it compare with HIV?
What Is Zika Virus?
Zika is a disease caused by the Zika virus, which itself is primarily transmitted through the bite of an infected mosquito, according to the U.S. Centers for Disease Control and Prevention (CDC). Zika can cause symptoms of fever, rash, joint pain and conjunctivitis (red eye). The symptoms are mild and can last from several days to a week.
While Zika is not considered life threatening, and people don't usually get sick enough to go to the hospital, the current outbreak has linked Zika to Guillain-Barré syndrome, which is a disorder in which a person's immune system attacks and damages their own nerve cells. Zika has also been linked to birth defects and poor pregnancy outcomes -- in particular, a serious condition called microcephaly, in which babies are born with heads much smaller than what's considered normal.
As of now, we do not know how or even if Zika causes Guillain-Barré syndrome or birth defects.
Now that we know what Zika virus is, how does it compare with HIV?
Mosquitoes: As stated above, Zika virus is transmitted primarily through mosquito bites. HIV, on the other hand, cannot be transmitted through mosquito bites, although this remains a common myth and frequently asked question.
Mother to child: Zika virus can be transmitted from mother to child during birth, though this is rare according to the CDC. Moreover, no cases of Zika virus transmission through breastfeeding have been reported.
HIV can also be transmitted from mother to child during birth; however, great strides have been made toward preventing mother-to-child transmission using HIV medicines for the mother during pregnancy together with meds for the baby after birth. Nevertheless, because breast milk can contain HIV, HIV-positive mothers in the U.S. are advised not to breastfeed and to use instant formula instead.
Blood: Both viruses can be transmitted through blood transfusions. Blood -- as well as semen (cum), pre-seminal fluid (pre-cum), rectal fluids, vaginal fluids and breast milk -- containing HIV "must come in contact with a mucous membrane or damaged tissue or be directly injected into the bloodstream (from a needle or syringe) for transmission to possibly occur," according to the CDC. We do not yet know if this is the same for Zika virus.
Sexual contact: We recently learned that Zika virus can be transmitted sexually and the CDC released interim guidelines for preventing sexual transmission of Zika virus. The data are based on three reported cases of sexual transmission; therefore, our understanding is still developing. For example, based on current data, we do not yet know how long Zika virus lives in semen and whether a woman can transmit to her sexual partners.
We have known for a long time that HIV can be transmitted sexually. However, if the HIV-positive partner is on treatment and has an undetectable viral load, the risk of transmission is almost reduced to zero. This strategy is known as "treatment as prevention." In fact, two large studies found zero HIV transmissions when the positive partner had an undetectable viral load. In addition to treatment as prevention, we also can offer HIV-negative individuals pre-exposure prophylaxis (PrEP), a daily pill that, when taken, can also greatly reduce transmission risk.
Saliva and urine: Brazilian researchers say they have found active levels of Zika virus in saliva and urine. However, this does not mean transmission is possible through saliva and urine. More research will be needed to shed light on that.
HIV cannot be transmitted through saliva and urine, despite this also being a common myth and frequently asked question.
As mentioned above, the most common symptoms of Zika are fever, rash, joint pain and conjunctivitis (red eye). The symptoms are mild and can last from several days to a week.
During acute HIV infection (the first few weeks after transmission), people can show flu-like symptoms, including fever, chills, night sweats and rashes. However, these symptoms can also be a sign of any viral infection, including the flu. Moreover, some people can go years without showing any symptoms. Therefore, it's important to get regularly tested for HIV.
Early Attention From Political Leaders
This week President Obama is calling for $1.8 billion dollars in emergency funding from Congress for the development of Zika virus tests, treatments and vaccines. Many senators have also called for a quick response to Zika from federal agencies.
In contrast, President Reagan did not speak publicly about HIV until six years after the first AIDS cases were reported.
Stigma and Discrimination
In some countries where the Zika outbreak is prominent, reproductive justice issues remain unaddressed in the initial responses, with governments asking women to avoid or postpone pregnancy. For example, El Salvador has advised postponing pregnancy until 2018. Moreover, some countries that have asked women to delay pregnancy have strict laws prohibiting abortion, including those for reasons of fetal abnormality.
By comparison, since the early days of the HIV epidemic, when AIDS was called "gay-related immune deficiency," or "GRID," stigma -- the notion that only a certain group of people or type of behavior could transmit HIV -- has existed. It continues to exist today.