Zika Virus

Zika virus.

Zika virus carrier Mosquito

 Zika virus is “spreading explosively” in the Americas, the WHO says. It causes birth defects in babies born to pregnant women, says the CDC. That agency has issued travel warnings for pregnant women in countries where the disease has been found. The virus is mainly spread by mosquitoes, although cases of sexual transmission have been reported.
Zika virus, first identified in Uganda in 1947, is transmitted by the same type of mosquito that carries dengue fever, yellow fever, and chikungunya virus. A mosquito bites an infected person and then passes those viruses to other people it bites. Outbreaks did not occur outside of Africa until 2007, when it spread to the South Pacific.
CDC Director Tom Frieden, MD, told reporters that “on occasion,” Zika may be spread through sexual contact or blood transfusions. The CDC has confirmed reports of Zika being spread through sex in some cases, meaning a person traveled to an area where Zika has broken out, got the virus, and gave the virus to a sexual partner who did not travel.
The CDC is aware of a report that Brazilian scientists have found the virus in the saliva and urine of infected people, Frieden said, but more information is needed.

• Symptoms of Zika virus:

The disease can cause fever, rash, joint pain, and redness in the whites of the eye. But most people won’t know they have it. “Only about 1 in 5 people with the virus will exhibit symptoms,” says Amesh Adalja, MD, a spokesman for the Infectious Diseases Society of America. “The vast majority have no symptoms at all.”
Adalja also says the virus rarely causes major complications. “It’s never been thought of as a severe infectious disease until now.” But in rare cases, Zika has been associated with Guillain-Barre syndrome, a disorder that can cause partial or complete paralysis, usually starting in the legs, most often temporary. An increase in that illness has been seen in areas such as French Polynesia and Brazil, where a Zika epidemic has taken place. A study released Feb. 29 suggested Zika may cause the syndrome but could not prove it. One U.S. case of Guillain-Barre that may be tied to Zika has been reported to the CDC, Frieden said. But “it’s very challenging to make the link in an individual case,” he said, as Guillain-Barre can also follow the flu or other infections.

• Connection between Zika, microcephaly, and pregnancy:

Zika-caused microcephaly.

The CDC on April 13 said Zika causes microcephaly in babies born to infected pregnant women. Microcephaly stunts a baby’s head growth, causing devastating, sometimes-fatal brain damage, and it can result in miscarriage or stillbirth.
The virus has caused panic in Brazil since it first appeared there in May. More than 1,100 babies in Brazil have been born with Zika-caused microcephaly. Brazil and several other nations have advised women to postpone pregnancy.
Although there are many causes of microcephaly in babies, including infections during pregnancy, genetic problems, and exposure to toxic substances during pregnancy, the CDC says research has provided enough evidence to show that Zika is among those causes. Also, research has suggested that infection during the earliest stages of pregnancy, when a baby’s organs are still forming, seems to be linked to the worst outcomes.
As of April 27, the CDC has confirmed 36 Zika infections in pregnant women. The agency earlier provided details on some of those, saying nine women had traveled to other countries and returned to the U.S. Two resulted in healthy births. Two resulted in miscarriages, and one baby was born with microcephaly. Two pregnancies are proceeding without known complications, and two women ended their pregnancies, the agency says. In one case, the pregnancy was ended after an ultrasound showed signs of severe brain damage in the fetus at 20 weeks. Details of the other termination were not reported.
The CDC also advises that men who have lived or traveled in areas with Zika infections and have a pregnant sex partner either use condoms or abstain from sex during the pregnancy. In January, the World Health Organization declared birth defects linked to the Zika virus an international public health emergency. That declaration will speed up research into the suspected connection between the virus and cases of microcephaly in babies of infected pregnant women.

• Test for Zika.

There are two ways to test for Zika. One test looks for pieces of the virus’ genetic code in people with active infections. But after the body clears the infection, which takes about 2 weeks after symptoms appear, that test won’t work.
On March 18, the FDA approved a more advanced version of this test that can distinguish whether a person has dengue, chikungunya, or Zika, rather than having to do three different tests. The new version will be sent to qualified labs, the CDC says. Since 80% of people with Zika don’t have symptoms, many people don’t know when they were infected and would not be eligible for this test. Another test looks for proteins called antibodies made by the immune system to fight the virus. It can find antibodies in the blood up to 3 months after a person is infected.
But this test isn’t very specific. It may mistakenly show a person has had Zika if they’ve been infected with other viruses, including dengue and chikungunya. A positive or inconclusive test result means a follow-up test is done by the CDC or a CDC-authorized lab. The FDA has approved the first phase of the second test, and the CDC is distributing it to qualified labs. Testing of amniotic fluid in pregnant women can also be done, although it's not clear how well this test would work for Zika, according to the CDC.

• Zika lead to other health conditions.

In rare cases, Zika has been linked to Guillain-Barre syndrome. That disorder can cause partial or complete paralysis, usually starting in the legs, most often temporary. An increase in that illness has been seen in areas such as French Polynesia and Brazil, where a Zika epidemic has taken place. A study released Feb. 29 suggested Zika may cause the syndrome but couldn't prove it. One U.S. case of Guillain-Barre that may be tied to the virus has been reported to the CDC, Frieden said. But “it’s very challenging to make the link in an individual case,” he said, as Guillain-Barre can also follow the flu or other infections.
There may be a link between Zika and an autoimmune disorder called acute disseminated encephalomyelitis (ADEM), according to research set to be presented at the American Academy of Neurology conference. The immune system of a person with the disorder attacks the myelin coating around nerve fibers in the brain and spinal cord, similar to multiple sclerosis.
The April study focused on six people who sought help at a hospital in Recife, Brazil. Tests showed that all six had Zika. Four developed Guillain-Barre syndrome and two developed ADEM.
Doctors in March reported the first case of brain swelling linked to Zika, in an 81-year-old man who was on a South Pacific cruise. The man ran a fever and lapsed into a coma. He was diagnosed with meningoencephalitis, or swelling of the membranes that cover the brain and spinal cord. The Zika virus was found in his spinal fluid. The man recovered after 38 days in the hospital.
On April 29, the CDC announced the first Zika-linked death in Puerto Rico, of a 70-year-old man who died in February from severe thrombocytopenia, which causes a low blood platelet count that can lead to internal bleeding.

• Protective measures can be taken.

If you plan to travel in affected areas, avoid mosquito bites by using mosquito repellent throughout the day. Also, wear long-sleeved shirts and long pants, both indoors and out. The mosquitoes that spread Zika are aggressive daytime biters often found indoors, which we’re not used to in the U.S., Weaver says. “You need to protect yourself all day long,” Weaver says. Even those who don’t know they have Zika can spread the disease. Weaver advises people who have traveled to affected regions to be extremely vigilant against mosquito bites when they return home, especially during the first 10 days. Some of these findings are being presented at a medical conference. They should be considered preliminary, as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.


Source: www.WebMD.com