--- title: Zika Virus Outbreak May Get Worse Before It Gets Better: WHO description: The mosquito-borne disease has already been reported in 46 countries canonical: https://time.com/4236797/zika-who-margaret-chan-brazil/ author: Rishi Iyengar article:opinion: false article:content_tier: free article:published_time: 2016-02-25T03:59:22.000Z article:modified_time: 2026-08-04T07:56:11.190Z article:section: Health og:title: Zika Crisis May Get Worse Before It Gets Better, WHO Says og:description: The mosquito-borne disease has already been reported in 46 countries og:url: https://time.com/4236797/zika-who-margaret-chan-brazil/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt39d9fb47b114ca0e/69887b1e2dce016ceb9e78f4/zika-virus-mosquitos.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 3240 og:image:height: 1823 og:image:alt: Brazil Faces New Health Epidemic As Mosquito-Borne Zika Virus Spreads Rapidly og:type: article twitter:card: summary_large_image twitter:title: Zika Crisis May Get Worse Before It Gets Better, WHO Says twitter:description: The mosquito-borne disease has already been reported in 46 countries twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt39d9fb47b114ca0e/69887b1e2dce016ceb9e78f4/zika-virus-mosquitos.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 ---  # Zika Crisis May Get Worse Before It Gets Better, WHO Chief Says > Sponsored content. 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Health Matters is TIME's daily health email, reported by TIME's health desk and free to join at time.com/newsletters. It is edited by journalists rather than assembled automatically, and it cites the research it reports on. #### Is Health Matters free? Yes. Health Matters is a free daily newsletter from TIME, available at time.com/newsletters. #### Who reads TIME's Health Matters newsletter? Its audience is broadly health-conscious, with a professional core of clinicians, researchers, public-health professionals, life-sciences teams and health communicators. ## Video: CDC Confirms Link Between Zika Virus And Birth Defects [Watch (HLS stream): CDC Confirms Link Between Zika Virus And Birth Defects](https://cdn.jwplayer.com/manifests/nYBEKNnO.m3u8) (1:03)  _Published 2016-01-18. Zika can infect embryonic cells that help form the brain, a lab study found_ by [Rishi Iyengar](https://time.com/author/rishi-iyengar/) ## Rishi Iyengar Feb 25, 2016 3:59 AM UTC  Aedes aegypti mosquitos are seen in a lab at the Fiocruz institute in Recife, Pernambuco state, Brazil on Jan. 26, 2016\. The mosquito transmits the Zika virus and is being studied at the institute. Aedes aegypti mosquitos are seen in a lab at the Fiocruz institute in Recife, Pernambuco state, Brazil on Jan. 26, 2016\. The mosquito transmits the Zika virus and is being studied at the institute.Mario Tama—Getty Images by [Rishi Iyengar](https://time.com/author/rishi-iyengar/) ## Rishi Iyengar Feb 25, 2016 3:59 AM UTC The Zika virus that has thus far affected close to 50 countries will likely continue to spread and pose a “formidable” challenge to eradicate, the head of the World Health Organization (WHO) [said](http://news.yahoo.com/zika-crisis-worse-gets-better-chief-213635583.html;%5Fylt=AwrBT.LIJs5W2uMA4r5XNyoA;%5Fylu=X3oDMTByMjB0aG5zBGNvbG8DYmYxBHBvcwMxBHZ0aWQDBHNlYwNzYw--) Wednesday. The mosquito-borne disease presents a “bigger menace” than any other recent epidemic and will possibly “get worse before it gets better,” Margaret Chan told Agence France-Presse during a fact-finding mission in Brazil. **Read More:** [_See All the Places Where the Zika Virus Has Spread_](http://labs.time.com/story/see-all-the-places-where-the-zika-virus-has-spread/) Other major disease outbreaks of recent years like Ebola and severe acute respiratory syndrome (SARS) may have been deadlier than Zika, whose symptoms resemble the flu. However, Chan said, they only affected nine and 26 countries respectively, whereas Zika has already been reported in [46 countries](http://time.com/4215197/zika-virus-queensland-pregnant-woman-australia-china/). Moreover, the _Aedes aegypti_ mosquito that passes on the virus exists in at least 130 countries, significantly increasing the possibility of a further spread. **Read More:** [_Zika’s Rapid Spread Explained in 3 GIFs_](http://time.com/4219582/zika-virus-how-spreads-mosquitoes/) Zika has also been linked with the birth defect [microcephaly](http://time.com/4209537/zika-birth-defects/) in children born to women with the disease, as well as a [paralysis disorder](http://time.com/4229778/cdc-zika-virus-guillain-barre-syndrome/) called Guillain-Barre syndrome, but neither relationship has been conclusively proved and much about the disease remains unknown. “We are dealing with a tricky virus, full of uncertainties, so we should be prepared for surprises,” Chan said. \[[_AFP_](http://news.yahoo.com/zika-crisis-worse-gets-better-chief-213635583.html;%5Fylt=AwrBT.LIJs5W2uMA4r5XNyoA;%5Fylu=X3oDMTByMjB0aG5zBGNvbG8DYmYxBHBvcwMxBHZ0aWQDBHNlYwNzYw--)\] ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/4236797/zika-who-margaret-chan-brazil/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/4236797/zika-who-margaret-chan-brazil/"},"headline":"Zika Crisis May Get Worse Before It Gets Better, WHO Chief Says","datePublished":"2016-02-25T03:59:22.000Z","dateModified":"2026-08-04T07:56:11.190Z","description":"The mosquito-borne disease has already been reported in 46 countries","url":"https://time.com/4236797/zika-who-margaret-chan-brazil/","keywords":["Zika","Virus","World Health Organization","ebola","SARS","infectious diseases"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/blt39d9fb47b114ca0e/69887b1e2dce016ceb9e78f4/zika-virus-mosquitos.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Rishi Iyengar","jobTitle":null,"url":"https://time.com/author/rishi-iyengar/"}],"articleSection":"Health","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/blt39d9fb47b114ca0e/69887b1e2dce016ceb9e78f4/zika-virus-mosquitos.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"Brazil Faces New Health Epidemic As Mosquito-Borne Zika Virus Spreads Rapidly","caption":"Aedes aegypti mosquitos are seen in a lab at the Fiocruz institute in Recife, Pernambuco state, Brazil on Jan. 26, 2016. 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