Update: Zika Bordering on Epidemic in the U.S.

By John Henry Dreyfuss, MDalert.com staff.

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  • Florida reports 10 new cases of Zika, the largest one-day announcement ever in the U.S.
  • Total case in U.S. approaches 1000.
  • No vector-borne cases yet reported in U.S.
  • Nearly 300 pregnant, Zika-infected Americans currently being monitored by the CDC.
  • Zika linked to microcephaly, seizures and spasticity, facial abnormalities, and problems with feeding and vision in newborns.
  • Disease linked to Guillain-Barré syndrome and Zika-related eye injury in adults.

It seems almost daily that alarms over Zika virus infection in the U.S. become more urgent. The Centers for Disease Control and Prevention (CDC) is currently monitoring hundreds of pregnant Americans and thousands of other adults are infected as well.

Florida health officials confirmed recently the discovery of 10 new cases of the Zika virus in parts of the state, according to a report by PBS Newshour.

The 10 new cases were the largest one-day total announced in the United States since the disease began spreading through Latin America last year, according to the British newspaper The Guardian. Nearly 1,000 people who have been infected with the virus are now living in the U.S., according to the CDC. Of those, 246 have been found in Florida this year, according to The Miami Herald.

In light of the recent finding, the Florida Department of Health said it would routinely update the public about new cases of the virus, including those accounted for by the Centers for Disease Control and Prevention (CDC).

President Obama is currently urging Congress to pass a bill to fund Zika prevention. "The president is trying to pressure Congress to pass a Zika-prevention bill that has been stalled for weeks. He criticized lawmakers for "playing politics" with public health. He says lawmakers should not take their summer recess before passing a bill," The New York Times reported.

By working to educate patients, physicians can help prevent microcephaly and other birth defects as well as Guillain-Barré syndrome and newly detected Zika-related eye injury in adults. Zika is carried by two mosquito species—Aedes aegypti and Aedes albopictus. (Figure 1 and 2.) The Aedes aegypti mosquito carries diseases that kill more people worldwide than any other creature, according to an article in The New York Times.

Federal health authorities and those in New York City "currently recommend that any woman who is pregnant, or planning on becoming pregnant, and who has spent time in one of the countries where the virus is endemic be tested. Because some 80% of the people who contract the virus show no symptoms, it is critical that doctors consider detailed travel histories of pregnant women and their partners to determine if they might be at risk. The virus can also be transmitted through sexual contact," according to the report in The New York Times.

Prior exposure to the dengue fever virus may increase the severity of Zika virus, according to a report on MedlinePlus.com. "Early stage laboratory findings suggest this connection between the two viruses may help explain the current Zika outbreak in Latin American and Caribbean countries, according to the international team of researchers."


Figure 1. Aedes aegypti.
(Source: By James Gathany [Public domain], via Wikimedia Commons.)

This month, the World Health Organization released a list of additional birth defects believed to be linked to Zika, including seizures and spasticity, facial abnormalities, and problems with feeding and vision; all part of a congenital Zika syndrome.

Nearly 6000 cases of microcephaly have been confirmed in Brazil. In the U.S. the first case of Zika microcephaly was reported in February. More have been observed since. Increasingly, infected pregnant women are choosing to terminate their pregnancies.

According to a recent report on The Huffington Post.com: "Americans in certain parts of the U.S. should be on higher alert than usual about mosquitoes because of the ongoing Zika virus epidemic in Latin America and the Caribbean, experts say. And while the highest risk zones are in Florida and Texas, more of the U.S. may be at risk. And, because, the signs and symptoms of Zika may mimic those of other less severe diseases (Figure 4)—or because infected adults may show no signs at all— many adults may simply not know that they have been infected.

"The world’s scientists generally agree that the mosquito-borne virus can cause severe birth defects like microcephaly. And scientists such as Anthony Cornel, a medical entomologist at the University of California, Davis, say that the Zika virus outbreaks in nearby parts of the world should make people in high-risk mosquito zones in the U.S. more vigilant about repelling bites. Zika is primarily transmitted by the Aedes Aegypti mosquito, which has been spotted as far north as New York." 

Figure 1. Aedes albopictus.
(Source: James Gathany/CDC [Public Domain] via Wikimedia Commons.)

“By midsummer you will start to see Zika cases transmitted by mosquitoes in the southern U.S.,” suggested Nitin S. Damle MD, MS, President of the American College of Physicians and a Clinical Assistant Professor of Medicine at the Alpert Medical School of Brown University.

Alarm with the U.S.

The CDC recently held briefings with governors from Alabama, Arizona, Florida, Louisiana, Mississippi, New York, Texas, Georgia, Hawaii, and California. The states reviewed preparedness plans that include CDC Emergency Response Teams. Mosquito control programs are now widespread in the United States. The mosquitoes that carry Zika currently inhabit at least half of the U.S. states. Mosquito-to-human transmission is considered a near certainty by physicians and the CDC. (Figure 3.)

By advocating for the use of EPA-approved insecticides and the use of condoms for any type of sexual intercourse—even among monogamous couples—physicians can significantly reduce the incidence and the spread of Zika infection.

Figure 3. These maps show the CDC’s best estimate of the potential range
of Aedes aegypti and Aedes albopictus mosquitoes in the U.S.
(Source: CDC.gov.)

Many experts believe that the first vector-borne transmission is highly likely. Americans already routinely travel to Zika-infested countries, are infected, and return home. Because Zika is sexually transmitted, infected males can easily pass the disease on to an intimate partner.

Because Americans spend more time outside during the day in the summer, they are more likely to be exposed to both of the mosquitoes that carry Zika. Both of these mosquitoes hunt during the day, as well as at dawn and dusk. Both are currently present within the continental U.S. If a mosquito feeds on an infected person it transmit the virus to the next person it bites.

The CDC recommends that Americans cover exposed skin and use an EPA-approved insect repellent any time they are outside, and that they use window screens and bed netting when inside.

Figure 4. Symptoms of Zika infection.
(Sources: Wikimedia Commons/By Beth.herlin (Own work) [CC BY-SA 4.0].)
Preventing Birth Defects

The physician should ask whether a patient has been exposed to Zika or has been infected. Men should wait 6 months before attempting to conceive and should wear a condom for that period during any type of sexual intercourse. A woman should wait 8 weeks before attempting to conceive after exposure to Zika. Microcephaly can be a devastating syndrome (Figure 5).

Figure 5. Symptoms of microcephaly.
(Sources: Wikimedia Commons/By Beth.herlin (Own work) [CC BY-SA 4.0].)
Infection Prevention

The 2 species of mosquitoes that carry Zika currently inhabit more than half of the states in the U.S., according to the CDC. Zika is currently spreading through both sexual and vector-borne transmission (Figure 6). The CDC recommends the following strategies for prevention:

  • Patients should use an EPA-approved insect repellent that contains DEET on all exposed skin, taking special care to apply repellent to the neck, ears, face, and scalp, as well as exposed lower arms and legs. DEET is safe for children, pregnant women, and all adults.
  • Patients should wear clothing that covers as much of the body possible—whenever possible.
  • EPA-approved insect repellents should be applied after sunscreen is applied.
Figure 6. Zika phylogenetic analysis map.
(Sources: Wikimedia Commons/By Khamar (Own work) [CC BY-SA 4.0].)