BETHESDA, MD 09 Mar 2016—Global research efforts are starting to answer
questions about how the Zika virus infects and affects people—but those answers
According to the World Health Organization (WHO),
the geographic distribution of Zika virus is rapidly increasing, and imported
cases of Zika virus infection have been reported from every region of the
world. Evidence is growing for a causal relationship between Zika virus
infection and Guillain-Barré syndrome as well as a growing list of fetal abnormalities.
And sexual transmission of the virus is more common than public health
officials previously thought.
"All of this news is alarming," said WHO
Director-General Margaret Chan, in a statement released March 8 in conjunction
with a teleconference on Zika virus infection and related neurologic disorders.
WHO on February 1 declared that the Zika virus-associated
cluster of microcephaly cases and other neurologic conditions reported in
Brazil is a public health emergency of worldwide concern. This is the same type
of emergency declaration that WHO issued for the Ebola virus disease (EVD) outbreak
that began in 2014.
The specifics for the two emergencies are
According to WHO, nearly 29,000 cases of EVD have
been confirmed worldwide during the outbreak, which has waned but not ended. More
than 11,000 people have died of the disease, and healthcare workers have been
particularly vulnerable to infection.
Three of the four cases of EVD that were diagnosed
in the United States occurred in healthcare workers, according to the Centers
for Disease Control and Prevention (CDC).
CDC states that most travelers are at very low risk
for EVD. But that's not the case for Zika virus—anyone who lives in or
travels to an area where the virus is found and has not already been infected
is at risk for becoming infected, according to the agency.
Zika virus transmission has not been documented in
the continental United States, but CDC reported 153 U.S. cases of
travel-acquired Zika virus infection through March 2. In addition, 107 locally
acquired cases have been confirmed in Puerto Rico, American Samoa, and the U.S.
Mosquito species that can harbor the virus are established
throughout about a dozen states, mostly in the southeast, and are found in portions
of about a dozen more states, according to CDC.
The virus is known to be transmitted through the
bite of an infected mosquito and via sexual contact. Maternal--fetal
transmission also occurs, according to CDC, but it is not known whether the
virus is transmitted in breast milk.
Zika virus was first identified in 1947 and was
long considered to pose little threat to humans.
"In general, the disease itself is very mild.
It's self-limiting, and many people don't even seek treatment," said
Suprat Saely Wilson, emergency department clinical pharmacist at the Detroit
Receiving Hospital and University Health Center in Michigan.
"The scary part of Zika is the complications
associated with it," Wilson said.
Those complications include catastrophic effects on
a developing fetus.
"We can now conclude that Zika virus is
neurotropic, preferentially affecting tissues in the brain and brain stem of
the developing fetus," WHO's Chan stated.
Specific fetal abnormalities that may be associated
with Zika virus infection include microcephaly, calcification of the developing
brain, intrauterine growth restriction, and fetal death.
Wilson's state, Michigan, does not harbor the
mosquito species that are known to transmit Zika virus. But healthcare
providers in the state may nonetheless encounter patients who acquired the
infection during travel and need medical advice.
Wilson said the absence of specific treatments for
Zika virus infection means that pharmacists have a supporting role, rather than
a leading one, in caring for patients who are ill.
"We probably would serve more of an education
role for other healthcare professionals" and for patients, Wilson said.
Because the burden of coping with Zika virus strongly
affects women, pharmacists can serve as a source of important healthcare
information for women, especially in ambulatory care sites.
"I do think this is a women's health
problem," said Meghan Jeffres, assistant professor of clinical pharmacy at
the University of Colorado Skaggs School of Pharmacy and Pharmaceutical
Sciences in Aurora.
That means helping women understand the importance
of using safe sex practices to minimize the risk of exposure from an infected
According to CDC, condom use—or avoiding sex
altogether—is necessary throughout pregnancy if the woman's partner is infected
with Zika virus or has traveled to an area where the virus is circulating.
Jeffres said pharmacists with dispensing roles have
become more involved in counseling patients about sexual health since emergency
contraception became available without a prescription. And she said state laws
that permit pharmacists to dispense oral contraceptives to patients without a
prescription from their physician help make such counseling a routine part of
Wilson, too, said patients "are comfortable
asking pharmacists about the different options" related to safe sex
"In ambulatory care settings, there's
definitely a role for pharmacists' education, working directly with
patients," she added.
CDC Director Thomas Frieden said during a February
26 media briefing that sexual transmission of Zika virus appears to be a
greater-than-anticipated public health threat.
During February 6–22, CDC received reports of 14 cases
of suspected sexual transmission of Zika virus. Six of the cases affected women
whose only known source of exposure was sexual contact with a symptomatic male
partner who had recently traveled to an area with ongoing Zika virus
transmission. Several of the cases remain under investigation, according to
"For most people in the U.S., the bottom line
is that pregnant women should postpone travel to Zika-affected areas,"
Frieden said. "As we get more reports of confirmed sexual transmission of
the Zika virus, we strongly encourage pregnant women and their male partner who
has traveled to or lives in an area where Zika is spreading to use protection
with condoms if they have sex."
He also recommended that women who have traveled to
an area where Zika virus has been spreading get tested for infection 2–12
weeks after they return home.
CDC on March 4 announced it will host a Zika
"action plan summit" to help state and local officials prepare for
expected instances of mosquito-borne transmission of the virus in the
continental United States.