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Zika fever

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Zika fever
SpecialtyInfectious diseases, neonatology Edit this on Wikidata

Zika fever (zica, in Portuguese[1]) is an illness caused by the Zika virus, a member of the genus flavivirus. The fever and virus are named after the Zika Forest in Uganda where the virus was first isolated.

Epidemiology

The very first known case of Zika fever was in a sentinel rhesus monkey stationed on a tree platform in the Zika Forest in Uganda in 1947. Population surveys at the time in Uganda found a 6.1% prevalence.[2] The first human cases were reported in Nigeria in 1954.[3] A few outbreaks have been reported in tropical Africa and in some areas in Southeast Asia.[4]

By using phylogenetic analysis of Asian strains it was estimated that Zika virus had moved to Southeast Asia by 1945.[2] In 1977–1978 Zika virus infection was described as a cause of fever in Indonesia.[5]

The first major outbreak, with 185 confirmed cases, was reported in 2007 in the Yap Islands of the Federated States of Micronesia.[6] A total of 108 cases were confirmed by PCR or serology and 72 additional cases were suspected. The most common symptoms were rash, fever, arthralgia and conjunctivitis, and no deaths were reported. The mosquito Aedes hensilli, which was the predominant species identified in Yap during the outbreak, was probably the main vector of transmission. While the way of introduction of the virus on Yap Island remains uncertain, it is likely to have happened through introduction of infected mosquitoes or a viraemic human with a strain related to those in Southeast Asia.[2][6] This was also the first time Zika fever had been reported outside Africa and Asia.[7]

File:Zika.jpg
Countries that have past or current evidence of Zika virus transmission (as of December 2015)[8]

In 2013 another large outbreak was reported in French Polynesia that was thought to be from an independent introduction of the virus from Asia than the Yap Island outbreak.[2]

In May 2015, Brazil officially reported its first 16 cases of the illness.[9] According to the Brazilian Health Ministry, as of November 2015 there was no official count of the number of people infected with the virus in Brazil, since the disease is not subject to compulsory notification. Even so, cases were reported in 14 states of the country. Mosquito-borne Zika virus is suspected to be the cause of 2,400 cases of microcephaly and 29 infant deaths in Brazil in 2015.[10]

Since first appearing in the Western Hemisphere in February 2014, it has rapidly spread throughout South and Central America, reaching Mexico in November 2015.[2][11] It has appeared sporadically in travellers to the United States and Europe but has not established person to person spread in those areas.[11]

Signs and symptoms

Symptoms are similar to other flaviviruses such as Dengue fever or chikungunya[7] but are milder in form and usually last four to seven days. The majority of cases (60-80%) are asymptomatic.[12] The main clinical symptoms in patients are low-grade fever, conjunctivitis, transient arthritis/arthralgia (mainly in the smaller joints of the hands and feet) and maculopapular rash that often starts on the face and then spreads throughout the body.[7] In general the disease symptoms are mild and short-lasting (2–7 days). Health officials studying the 2015 Brazilian outbreak suspect that the disease may cause microcephaly (a birth defect) in the newborn babies of infected women.[13] However, there are very few case reports in the literature.[6] Hemorrhagic manifestations have been documented in only one instance, hematospermia (red–brown fluid in ejaculate).[14] During the outbreak in French Polynesia there was also noted to be a concomitant increase in cases of Guillain-Barré Syndrome which could have been due to Zika but has not been proven.[7][12][15]

As of November 2015, reports from the Brazilian Health Ministry alerted people to a previously unknown connection between the zika virus and cases of newborn microcephaly in Northeastern Brazil.[16][17][18] The Ministry later confirmed [19][20] the previously suspected connection between zika infection of pregnant women and newborn microcephaly, with at least 2,400 reported cases of microcephaly in the country this year as of 12 December 2015, and 29 fatalities.[10][21] According to a CNN report, Brazilian health officials were also recommending that parents consider putting off pregnancy due to the sharp increase in cases of microcephaly.[22]

Diagnosis

Zika virus can be identified by RT-PCR in acutely ill patients. However, the period of viremia can be short[23] and the WHO recommends RT-PCR testing be done on serum collected within 1 to 3 days of symptom onset or on saliva or urine samples collected during the first 3 to 5 days.[24] Later on, serology through detection of specific IgM and IgG antibodies can be used. Serological cross-reactions with closely related flaviviruses such as dengue and west nile fever as well as vaccines to flaviviruses are possible.[23][25][26] The US CDC advises that the differential diagnosis of suspected Zika virus infection is broad and includes in addition to dengue "leptospirosis, malaria, rickettsia, group A streptococcus, rubella, measles, and parvovirus, enterovirus, adenovirus, and alphavirus infections (e.g., Chikungunya, Mayaro, Ross River, Barmah Forest, O’nyong-nyong, and Sindbis viruses)."[27]

Reservoir

Zika virus is a mosquito-borne flavivirus closely related to dengue virus. While mosquitoes are the vector, the reservoir species remains unknown, though serological evidence has been found in West African monkeys.[28]

Transmission

Transmission is via the bite of mosquitoes from the Aedes genus, primarily Aedes aegypti in tropical regions and Aedes albopictus in more temperate. During the 2007 outbreak on Yap Island in the South Pacific, Aedes hensilli was the vector, while Aedes polynesiensis spread the virus in French Polynesia in 2013.[24]

There have also been confirmed reports of 2 cases of sexual transmission and 2 of perinatal transmission.[2] Like other flaviviruses it could potentially be transmitted by blood transfusion and several affected countries have developed strategies to try and screen blood donors.[29]

Prevention

There is currently no vaccine.[23] The virus is spread by mosquitoes, making vector control and avoidance an essential element to disease control. The US Centers for Disease Control recommends that individuals:[30]

  • Cover exposed skin by wearing long-sleeved shirts and long pants.
  • Use an insect repellent
  • Use products with the following active ingredients:
  • Always follow product directions and reapply as directed:
  • If you are also using sunscreen, apply sunscreen first, let it dry, then apply insect repellent.
  • Follow package directions when applying repellent on children. Avoid applying repellent to their hands, eyes, or mouth.
  • Use permethrin-treated clothing and gear (such as boots, pants, socks, and tents). You can buy pre-treated clothing and gear or treat them yourself.
    • Clothing treated with permethrin remains protective after multiple washings. See the product information to find out how long the protection will last.
    • If treating items yourself, follow the product instructions carefully.
    • Do not use permethrin directly on skin.
  • Stay and sleep in screened-in or air-conditioned rooms.
  • Use a bed net if the area where you are sleeping is exposed to the outdoors.

Treatment

There is currently no specific treatment for Zika virus infection. Care is supportive with treatment of pain, fever and itching.[24] Some authorities have recommended against using aspirin and other NSAIDs as these have been associated with hemorrhagic syndrome when used for other flaviviruses.[23] Additionally, aspirin use is generally avoided in children due to the risk of Reye syndrome.[31]

See also

References

  1. ^ http://dicionarioegramatica.com.br/2015/12/01/zika-virus-virus-da-zica-em-portugues/ DicionarioeGramatica.com
  2. ^ a b c d e f Gatherer, Derek; Kohl, Alain (2015-12-18). "Zika virus: a previously slow pandemic spreads rapidly through the Americas". Journal of General Virology. doi:10.1099/jgv.0.000381.
  3. ^ 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.
  4. ^ Simpson, DIH. Zika virus infection in man (1964). Trans. Roy. Soc. Trop. Med. Hyg., 58:335–338.
  5. ^ 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.
  6. ^ a b c 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
  7. ^ a b c d Musso, D.; Nilles, E.J.; Cao-Lormeau, V.-M. "Rapid spread of emerging Zika virus in the Pacific area". Clinical Microbiology and Infection. 20 (10): O595 – O596. doi:10.1111/1469-0691.12707.
  8. ^ http://www.cdc.gov/zika/geo/index.html
  9. ^ 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
  10. ^ a b "MONITORAMENTO DOS CASOS DE MICROCEFALIAS NO BRASIL (Portuguese)" (PDF). CENTRO DE OPERAÇÕES DE EMERGÊNCIAS EM SAÚDE PÚBLICA SOBRE MICROCEFALIAS. December 12, 2015. Retrieved December 24, 2015.
  11. ^ a b 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.
  12. ^ a b "Factsheet for health professionals". ecdc.europa.eu. Retrieved 2015-12-22.
  13. ^ 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.
  14. ^ Foy BD, Kobylinski KC, Foy JL, Blitvich BJ, Travassos da Rosa A, Haddow AD, teal (May 2011). "Probable non-vector-borne transmission of Zika virus, Colorado, USA" (PDF). Emerging Infectious Diseases. 17 (5): 880–882. doi:10.3201/eid1705.101939. PMID 21529401.
  15. ^ http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20720
  16. ^ Microcephaly in Brazil potentially linked to the Zika virus epidemic, ECDC assesses the risk, http://ecdc.europa.eu/en/press/news/_layouts/forms/News_DispForm.aspx?ID=1329&List=8db7286c-fe2d-476c-9133-18ff4cb1b568&Source=http%3A%2F%2Fecdc.europa.eu%2Fen%2FPages%2Fhome.aspx
  17. ^ "Zika virus: Health alerts in South America and Caribbean following fears illness may cause birth deformities" http://www.independent.co.uk/news/world/americas/health-alerts-in-south-america-and-caribbean-following-fears-spreading-zika-virus-may-cause-birth-a6740301.html
  18. ^ "Brazil reports 739 suspected microcephaly cases in nine states" http://agenciabrasil.ebc.com.br/en/geral/noticia/2015-11/brazil-reports-739-suspected-microcephaly-cases-nine-states
  19. ^ (In Portuguese) Governo confirma relação entre zika vírus e epidemia de microcefalia http://www.bbc.com/portuguese/noticias/2015/11/151127_confirma_zika_microcefalia_mdb
  20. ^ Brazil confirms zica virus link to fetal brain-damage outbreak, http://www.reuters.com/article/brazil-health-zica-idUSL1N13N0NH20151128#x4sFsU0kCzW0J1Uk.97
  21. ^ (In Portuguese) País registra 1.248 casos de microcefalia e sete mortes; maioria em PE http://noticias.uol.com.br/saude/ultimas-noticias/redacao/2015/11/30/pais-tem-1248-casos-de-microcefalia-ligacao-com-virus-zika-e-confirmada.htm
  22. ^ "Brazil warns against pregnancy due to spreading virus - CNN.com". CNN. Retrieved 2015-12-24.
  23. ^ a b c d "Factsheet for health professionals". ecdc.europa.eu. Retrieved 2015-12-24.
  24. ^ a b c "WPRO | Zika virus". www.wpro.who.int. Retrieved 2015-12-24.
  25. ^ Faye O, Faye O, Dupressoir A, Weidmann M, Ndiaye M, Alpha Sall A (Sep 2008). "One-step RT-PCR for detection of Zika virus". J Clin Virol. 43 (1): 96–101. doi:10.1016/j.jcv.2008.05.005.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  26. ^ Lanciotti RS, Kosoy OL, Laven JJ, et al. "Genetic and serologic properties of Zika virus associated with an epidemic, Yap State, Micronesia, 2007". Emerging Infectious Diseases. 14: 1232–9. doi:10.3201/eid1408.080287.
  27. ^ "For Health Care Providers: Clinical Evaluation & Disease | Zika virus | CDC". www.cdc.gov. Retrieved 2015-12-24.
  28. ^ Brack, Manfred (2012). Agents Transmissible from Simians to Man. p. 35. ISBN 3642719112.
  29. ^ "Blood safety and zoonotic emerging pathogens: now it's the turn of Zika virus!". Blood Transfusion. doi:10.2450/2015.0187-15.
  30. ^ "Zika Virus in Central America—Watch—Level 1, Practice Usual Precautions—Travel Health Notices | Travelers' Health | CDC". wwwnc.cdc.gov. Retrieved 2015-12-24.
  31. ^ Fulginiti, Vincent; et al. (1982). "Aspirin and Reye Syndrome". Pediatrics. 69 (6): 810–812. {{cite journal}}: Explicit use of et al. in: |last2= (help)
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