Zika fever

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Zika fever
Classification and external resources
Rash during Zika fever infection
A baby with microcephaly (left) compared to a baby with a typical head size. Scientists think Zika fever causes microcephaly in fetuses

Zika fever is an illness caused by the Zika virus. The Zika virus belongs to the genus Flavivirus, like dengue fever and chikungunya.[1] However, Zika fever is usually not as bad as those illnesses. Most people who get the Zika virus (60-80%) have no symptoms.[2][3]

People who do have symptoms usually have a low fever, conjunctivitis, joint pain (mainly in the hands and feet), and a rash. The rash often starts on the face and then spreads to the rest of the body.[1] Usually, the symptoms are not very bad, and get better after 2 to 7 days.

Starting in 2015, there has been an outbreak of Zika virus (meaning that many people have gotten the virus) in Brazil. Scientists think that when a woman with the Zika virus is pregnant, she can give the virus to her fetus. Scientists think this can cause microcephaly,[4] a birth defect that causes a baby to have a smaller head than usual.[5] This can cause intellectual disability and other problems in the brain, like seizures.[6] Because of this, in January 2016, the United States Centers for Disease Control and Prevention warned pregnant women not to travel to Brazil, Colombia, El Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Suriname, Venezuela, or Puerto Rico, because of the risk of getting the Zika virus there.[7]

In places where the Zika virus lives, people are more likely to have birth defects, neurological problems like Guillain-Barré syndrome, and autoimmune diseases.[8]

Diagnosis[change | change source]

Diagnosing Zika fever is difficult for a few reasons. First, Zika fever causes many of the same signs and symptoms as many other viruses.[9]

Second, special laboratory tests have to be done to prove that a person has Zika virus. For example, when the virus is in a person's blood or urine, it can be found by using a special test that looks for the virus's RNA in the blood. However, the Zika virus often does not stay in the blood for very long.[10] Also, because most people with the Zika virus have no symptoms, they do not know that they need to be tested. Blood tests that look for specific antibodies (which the body sends out to fight the Zika virus) can also be done. However, these tests are expensive and have to be done in special laboratories that do not exist everywhere.[11]

If tests cannot prove that a person has Zika virus, it can be difficult to figure out whether a person has Zika fever or a different infection. The United States Centers for Disease Control and Prevention (CDC) says that before doctors diagnose a person with Zika fever, they should think about whether the person could have one of many other infections. Examples of these infections include:[12]

Transmission[change | change source]

Humans get the Zika virus after being bitten by mosquitoes from the Aedes genus.[11] Scientists have proven that at least eight different species of mosquitoes from the Aedes genus can spread the Zika virus to humans.[13] Mosquitoes pick up the Zika virus after they bite other animals that have the virus.

Zika virus can be passed from one person to another during sexual intercourse.[14] It can also be passed from a mother to her fetus during pregnancy.

Prevention[change | change source]

Protecting against mosquitoes - like by using a mosquito net while sleeping - is the best way to avoid getting the Zika virus

There is no vaccine for Zika virus, though the United States National Institutes of Health is trying to make one.[15][9][10]

The best way for a person to protect themselves against the Zika virus is to protect themselves against mosquitoes. For example, if people are traveling to places where the Zika virus lives, they should:[16]

  • Wear long-sleeved shirts and long pants
  • Use bug spray
  • Stay and sleep in rooms that are protected by window and door screens, and that have air conditioning (if possible)
  • Use a mosquito net when sleeping

Treatment[change | change source]

Today, there is no treatment or cure for Zika fever. Medical professionals can only give "supportive care," which means they can only treat the virus's symptoms. For example, they can give medicines to help with pain, fever, and itching.[13] However, some scientists say that doctors should not give medicines like aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs), which are commonly used for pain and fever. This is because people with similar viruses who take these medicines have been more likely to have bleeding problems.[10]

There are no known anti-viral medications (medicines which kill viruses) which will kill the Zika virus.

Because there are no treatments that will cure the Zika virus once a person has it, scientists suggest that pregnant women do everything they can to avoid getting the virus.[17] Once a pregnant woman has the Zika virus, there is nothing anyone can do to keep her fetus from getting infected too.

Epidemiology[change | change source]

Zika fever was first discovered in 1947, in a rhesus monkey in the Zika Forest in Uganda.[11] The first human cases were reported in Nigeria in 1954.[18] A few outbreaks have been reported in tropical Africa and in some parts of Southeast Asia,[19] but not India.[20] In 1977–1978, Zika virus caused fevers in Indonesia.[21]

Countries where people have gotten Zika virus (as of January 2016)[22]

The first major outbreak happened in 2007 in Micronesia's Yap Islands. 185 people were proven to have the Zika virus.[23] This was the first time Zika fever had been reported outside Africa and Asia.[1] In 2013, another large outbreak happened in French Polynesia.[14]

In May 2015, Brazil officially reported its first 16 cases of Zika fever.[24] By November 2015, Zika fever had appeared in 14 states in Brazil. Zika virus is thought to have caused 2,400 cases of microcephaly and 29 infant deaths in Brazil in 2015.[25]

Since first appearing in the Western Hemisphere in February 2014, Zika fever has spread quickly throughout South America and Central America. It appeared in Mexico in November 2015.[14][26]

On January 24, 2016, the World Health Organization warned that the Zika virus is likely to spread to nearly all countries of the Americas. This is likely since the mosquito that spreads the virus, Aedes aegypti, lives in all of the countries in the Americas, except for Canada and Chile.[27][28]

On February 1, 2016, the World Health Organization said that the Zika virus was a "public health emergency."[29] They also said the Zika virus was "spreading explosively" (very quickly), and that in the next year, as many as 3 million to 4 million people could get the virus.[29]

Related pages[change | change source]

References[change | change source]

  1. 1.0 1.1 1.2 Musso, D.; Nilles, E.J.; Cao-Lormeau, V.-M. (2014). "Rapid spread of emerging Zika virus in the Pacific area". Clinical Microbiology and Infection. 20 (10): O595–O596. doi:10.1111/1469-0691.12707. PMID 24909208.
  2. "Factsheet for health professionals". ecdc.europa.eu. Retrieved 2015-12-22.
  3. Ghawche, F.; Musso, D.; Mallet, H. P.; Baudouin, L.; Valour, F.; Lastère, S.; Leparc-Goffart, I.; Larre, P.; Watrin, L.; Oehler, E. (6 March 2014). "Zika virus infection complicated by Guillain-Barré syndrome – case report, French Polynesia, December 2013". Eurosurveillance. 19 (9): 20720. doi:10.2807/1560-7917.ES2014.19.9.20720. PMID 24626205 – via www.eurosurveillance.org.
  4. Lisa Schnirring (30 Nov 2015). "Zika virus spreads to more countries". Center for Infectious Disease Research and Policy, U. of Minnesota Academic Health Center. Retrieved 11 Dec 2015.
  5. Leviton, A.; Holmes, L. B.; Allred, E. N.; Vargas, J. (2002). "Methodologic issues in epidemiologic studies of congenital microcephaly". Early Hum Dev. 69 (1): 91–105. doi:10.1016/S0378-3782(02)00065-8. PMID 12324187.
  6. Ashwal, S.; Michelson, D.; Plawner, L.; Dobyns, W. B. (2009). "Practice Parameter: Evaluation of the child with microcephaly (an evidence-based review)". Neurology. 73 (11): 887–897. doi:10.1212/WNL.0b013e3181b783f7. PMC 2744281. PMID 19752457.
  7. "CDC issues interim travel guidance related to Zika virus for 14 Countries and Territories in Central and South America and the Caribbean". Centers for Disease Control and Prevention. 2016-01-15. Retrieved 2016-01-17.
  8. 17 January 2016: Neurological syndrome, congenital malformations, and Zika virus infection – Epidemiological Update http://www.paho.org/hq/index.php?option=com_content&view=category&layout=blog&id=1218&Itemid=2291 Archived 2016-01-26 at the Wayback Machine
  9. 9.0 9.1 Fauci, Anthony S.; Morens, David M. (2016-01-13). "Zika Virus in the Americas — Yet Another Arbovirus Threat". New England Journal of Medicine. 374 (7): 601–604. doi:10.1056/NEJMp1600297. ISSN 0028-4793. PMID 26761185.
  10. 10.0 10.1 10.2 "Factsheet for health professionals". ecdc.europa.eu. Retrieved 2015-12-24.
  11. 11.0 11.1 11.2 Hayes, Edward B. (2009). "Zika Virus Outside Africa". Emerging Infectious Diseases. 15 (9): 1347–1350. doi:10.3201/eid1509.090442. PMC 2819875. PMID 19788800.
  12. "For Health Care Providers: Clinical Evaluation & Disease | Zika virus | CDC". www.cdc.gov. Retrieved 2015-12-24.
  13. 13.0 13.1 "WPRO | Zika virus". www.wpro.who.int. Retrieved 2015-12-24.
  14. 14.0 14.1 14.2 Gatherer, Derek; Kohl, Alain (2015-12-18). "Zika virus: a previously slow pandemic spreads rapidly through the Americas". Journal of General Virology. 97 (2): 269–273. doi:10.1099/jgv.0.000381. PMID 26684466.
  15. "U.S. Launches 'Full-court Press' for a Zika Vaccine". TIME.com. Retrieved 23 January 2016.
  16. "Zika Virus in Central America—Watch—Level 1, Practice Usual Precautions—Travel Health Notices | Travelers' Health | CDC". wwwnc.cdc.gov. Retrieved 2015-12-24.
  17. Petersen EE, Staples JE, Meaney-Delman D, Fischer M, Ellington SR, Callaghan WM, Jamieson DJ. Interim Guidelines for Pregnant Women During a Zika Virus Outbreak - United States, 2016. MMWR Morb Mortal Wkly Rep. 2016 Jan 22;65(2):30-3. doi: 10.15585/mmwr.mm6502e1 PMID 26796813
  18. MacNamara, F. N. (1954-03-01). "Zika virus : A report on three cases of human infection during an epidemic of jaundice in Nigeria". Transactions of the Royal Society of Tropical Medicine and Hygiene. 48 (2): 139–145. doi:10.1016/0035-9203(54)90006-1. ISSN 0035-9203. PMID 13157159.
  19. Simpson, DIH. Zika virus infection in man (1964). Trans. Roy. Soc. Trop. Med. Hyg., 58:335–338.
  20. Smithburn, K. C.; Kerr, J. A.; Gatne, P. B. (1954-04-01). "Neutralizing antibodies against certain viruses in the sera of residents of India". Journal of Immunology (Baltimore, Md.: 1950). 72 (4): 248–257. doi:10.4049/jimmunol.72.4.248. ISSN 0022-1767. PMID 13163397. S2CID 2079191.
  21. Olson, J. G.; Ksiazek, T. G. (1981-01-01). "Zika virus, a cause of fever in Central Java, Indonesia". Transactions of the Royal Society of Tropical Medicine and Hygiene. 75 (3): 389–393. doi:10.1016/0035-9203(81)90100-0. ISSN 0035-9203. PMID 6275577.
  22. "Geographic Distribution - Zika virus - CDC". www.cdc.gov. 5 November 2014. Retrieved 2016-01-18.
  23. Duffy MR, Chen TH, Hancock WT, et al. Zika Virus Outbreak on Yap Island, Federated States of Micronesia (2009). The New England Journal of Medicine. 360:2536–43, http://content.nejm.org/cgi/reprint/360/24/2536.pdf[permanent dead link]
  24. Globo News May 14, 2015, Brazilian Health Ministry confirms first cases of zika in two states, http://g1.globo.com/bemestar/noticia/2015/05/ministerio-da-saude-confirma-16-casos-de-zika-virus-no-brasil.html
  26. Dyer, Owen (2015-12-23). "Zika virus spreads across Americas as concerns mount over birth defects". BMJ. 351: h6983. doi:10.1136/bmj.h6983. ISSN 1756-1833. PMID 26698165. S2CID 34837824.
  27. Zika Virus likely to spread throughout the Americas, says WHO. https://www.theguardian.com/world/2016/jan/25/zika-virus-likely-spread-throughout-americas-says-who
  28. “PAHO Statement on Zika Virus Transmission and Prevention” http://www.paho.org/hq/index.php?option=com_content&view=article&id=11605&Itemid=0&lang=en
  29. 29.0 29.1 Pearson, Michael (February 1, 2016). "Zika virus sparks 'public health emergency'". CNN. Retrieved February 1, 2016.