- 3 March 2014: 
Public health authorities of Chile confirmed the detection of autochthonous transmission of Zika virus infection in Easter Island (Chile) since February 2014, coinciding with transmission in the Pacific Islands. The presence of the virus was detected until June of the same year and was not detected later.

- 11 February 2015: The authorities of Brazil responded to a PAHO request for information confirming clusters of cases of rash in the State of Maranhao, in the northeast of Brazil. Up to 22 of January, 45 cases of acute febrile illness had been reported in municipality of Caxias in the State of Maranhao.  The cases reported fever, muscle and joint pain, rash, and headache, but no severe cases or deaths were reported. Samples from 25 patients were tested 14 samples resulted positive for dengue and all samples were negative for Chikungunya, rubella or measles.

- 29 April 2015: Authorities of Brazil shared a preliminary report from the Bahia State laboratory that samples tested positive for Zika virus but confirmatory tests from the National reference laboratory were still pending. Read the Press release.

- 7 May 2015: PAHO issued an Epidemiological Alert, titled "Zika virus infection,"[1] describing the infection and giving Member States recommendations for leveraging existing surveillance systems for dengue and Chikungunya to increase their sensitivity to detect possible cases of Zika virus infection. The Alert also included details on laboratory testing, case management, and prevention and control measures including recommendations to travelers.  

- 14 May 2015: The Evandro Chagas Institute, a national reference laboratory, confirmed a positive result for Zika virus in samples taken from the States of Rio Grande do Norte and Bahia in Brazil.  

- 22 May 2015: The first case of Zika was confirmed in the State of São Paulo, Brazil, in a 52-year-old man. The State of Sao Paulo is the most populous in Brazil, with over 44 million persons. The infection was confirmed by the Adolfo Lutz laboratory in Sao Paulo and re-confirmed by the Evandro Chagas Institute.  

- 31 May 2015: The authorities of Brazil reported that five states were reporting circulation of Zika virus-Alagoas, Bahia, Para, Rio Grande do Norte, and São Paulo.  

- 9 June 2015: The authorities of Brazil reported that the number of States with Zika circulation had increased to eight-- Alagoas, Bahia, Maranhao, Para, Rio Grande do Norte, Rio de Janeiro, Roraima, Sao Paulo. 

- 9 July 2015: The authorities of Brazil reported that 58 cases of neurological complications temporally associated with rash illness were identified in the State of Bahia until 4 July 2015. Of these 58 cases, 29 cases were confirmed as Guillain-Barré syndrome by clinical criteria. Among the 29 confirmed cases, 19 cases had a previous history of Zika virus infection and 2 cases presented serology reactive for dengue. 

- 14 July 2015: The Parana State Department of Health[2] confirms its first case of Zika virus infection in a 48-year-old female from the municipality of São Miguel do Iguaçu. Parana State is located in the South of Brazil. The case was initially diagnosed as dengue after developing symptoms in May 2015, but later laboratory test confirmed as ZIKV. Paraná state shares a border with Argentina and Paraguay. 

- 16 July 2015: The authorities of Brazil reported that the number of States with Zika circulation had increased to 12 States: Alagoas, Bahia, Ceara, Maranhao, Para, Paraiba, Parana, Pernambuco, Rio Grande do Norte, Rio de Janeiro, Roraima, and Sao Paulo. 

- 17 July 2015: The department of Health for the State of Bahia[3] of Brazil reported 101 cases of neurological complications this year. Of these, 49 were confirmed as Guillain-Barré Syndrome (GBS) by clinical criteria, 47 of which had prior history of chikungunya, dengue or Zika virus infections. Salvador, the capital of the State of Bahia, reported the highest number of confirmed cases, with 38 cases.

- 16 September 2015: The Department of Health for the State of Bahia[4] of Brazil reports 52,403 cases of Zika, which represents an incidence of 346 cases per 100,000 population. 

- 16 October 2015: PAHO published an Epidemiological Update, titled "Zika virus infection,"[5] with more recommendations for countries of the Americas, including an interim case definition.  

- 16 October 2015: The authorities of Colombia confirmed to PAHO/WHO the first cases of Zika virus in Bolivar Department. Nine cases of Zika virus had been confirmed[6] by the national reference laboratory at the National Institute of Health and re-confirmed by the U.S. Centers for Diseases Control and Prevention (US CDC).

- 23 October 2015: PAHO/WHO received information from the Brazil IHR National Focal Point regarding communications from the Pernambuco State Health Department (SES/PE), concerning an unusual  increase in the number of cases of microcephaly since August 2015. Altogether there were 26 cases of newborns with microcephaly detected at various specialized public and private hospitals. The newborns presented microcephaly, below the 5th percentile of the Head circumferences per the WHO standard.

- 2 November 2015: Authorities of Suriname reported to PAHO/WHO two cases of Zika virus infection that had been locally-acquired.

- 11 November 2015: The authorities of Brazil officially declared a National Public Health Emergency due to a detected increase in cases of microcephaly in the state of Pernambuco, Paraiba and Rio Grande do Norte in the northeast of the country.

- 16 November 2015: Authorities of El Salvador reported 10 suspected cases of Zika virus infection. The suspected cases presented with fever, conjunctivitis, arthralgia and malaise. The cases came from 6 municipalities and none of the cases had any previous history of travel. Differential diagnosis was performed for dengue by NS1, RT-PCR, IgM and chikungunya by RT-PCR, and all were negative except one sample that was positive for dengue by IgM. 

- 17 November 2015: PAHO published an Epidemiological Alert, titled "Increase of microcephaly in the northeast of Brazil,"[#] concerning the unusual increase of microcephaly in some northeast states of Brazil.

- 24 November 2015: Authorities of El Salvador reported that three samples tested positive for Zika virus by RT-PCR at the International Reference Laboratory at the U.S. CDC on 19 November.

- 24 November 2015: Authorities of El Salvador reported that three samples tested positive for Zika virus by RT-PCR at the International Reference Laboratory at the U.S. CDC on 19 November.

- 25 November 2015: Detection of local transmission of Zika virus was confirmed in Guatemala

- 27 November 2015: Authorities of Paraguay reported to PAHO the first detected case of local transmission of Zika virus. 

- 30 November 2015:Venezuela concluded an investigation indicating the detection of local transmission of Zika virus. Mexico also announced the detection of local transmission of Zika virus.  

- 1 December 2015: PAHO published an Epidemiological Alert titled, "Neurological syndrome, congenital malformations and Zika virus infection: implications for public health in the Americas."[7], highlighting the increased detection in congenital anomalies and neurological syndromes in Brazil.  The alert also made a series of recommendations for enhanced surveillance of neurological syndromes and congenital malformations and included recommendations for the monitoring of pregnant women and newborns with congenital malformations in the context of Zika virus circulation. 

- 2 December 2015: Public health authorities of Panama notified autochthonous cases of Zika virus disease. 

- 16 December 2015: Authorities of Honduras reported the detection of Zika virus disease.  

- 21 December 2015: France IHR National Focal Point reported the confirmation of local transmission of Zika virus in two of its overseas territories-French Guiana and Martinique

- 30 December 2015: The United States of America reported the detection of local transmission of Zika virus in Puerto Rico. 

- 4 January 2016: Detection of Zika virus transmission was reported in Haiti

- 8 January 2016: El Salvador reported a detected increase of GBS cases with 46 cases detected from December 2015 to 6 January 2016. Two deaths with suspected GBS were reported, one of which had multiple underlying chronic illnesses.

- 15 January 2016: Authorities from Barbados, Ecuador, and Guyana, notified their first confirmed cases of local transmission of Zika virus.

- 16 January 2016: Authorities from Bolivia reported the detection of the first locally-acquired case of Zika virus disease. 

- 17 January 2016: PAHO published an Epidemiological Update titled "Neurological syndrome, congenital malformations and Zika virus infection"[8] detailing increased reports of GBS in more countries of the Americas and alerting national authorities to enhance surveillance systems to detect such increases. The update also reported in ophthalmological findings in three children with microcephaly and on emerging evidence of vertical transmission of Zika virus, detected in four cases of congenital malformations. 

- 18 January 2016:  Authorities of France reported the detection of local transmission of Zika virus in the overseas collectivities of Saint Martin and Guadeloupe.

- 23 January 2016:The Dominican Republic reported the detection of local transmission of Zika virus. 

- 25 January 2016: The United States of America reported the detection of local transmission of Zika virus in the U.S. Virgin Islands.

- 27 January 2016: Authorities from Nicaragua reported the detection of local transmission of Zika virus.  

- 28 January 2016: Authorities from the Netherlands reported the detection of local transmission of Zika virus in the island of Curacao.  

- 29 January 2016: Authorities from Suriname reported an increase of GBS. The detection of locally-acquired Zika virus disease was reported in Costa Rica.

- 30 January 2016: The authorities of Jamaica reported their first case of Zika virus infection and Colombia reported an increase in GBS cases. 

- 1 February 2016: The first meeting of the Emergency Committee (EC) convened by the WHO Director-General under the International Health Regulations (2005) regarding clusters of microcephaly cases and other neurologic disorders in some areas affected by Zika virus was held by teleconference on 1 February 2016. The Committee advised that the recent cluster of microcephaly cases and other neurologic disorders reported in Brazil, following a similar cluster in French Polynesia in 2014, constitutes a Public Health Emergency of International Concern (PHEIC). Based on this advice the Director-General declared a Public Health Emergency of International Concern (PHEIC) on 1 February 2016. The Director-General endorsed the Committee's advice and issued them as Temporary Recommendations under IHR (2005). Read the complete WHO statement.  

- 5 February 2016: The United States of America reported the laboratory confirmation of one case of sexually transmitted Zika virus. The case had no travel history to areas of Zika virus circulation and resided in an area where local meteorological conditions at the time would not have supported mosquito activity.

- 10 February 2016: PAHO published an Epidemiological Update, titled "Reported increase of congenital microcephaly and other central nervous system symptoms"[#] providing an update on the situation in the Region of the Americas. 

- 15 February 2016: Authorities from the Netherlands reported the first autochthonous case of Zika virus infection on the island of Bonaire

- 16 February 2016: Authorities from the Netherlands reported the first four autochthonous cases of Zika on the island of Aruba

- 17 February 2016: PAHO published the first weekly Epidemiological Update, titled "Zika virus infection"[#] providing an update on the situation in the Region of the Americas.  See the weekly Epidemiological Updates

- 18 February 2016: Authorities from Trinidad and Tobago reported the first case of autochthonous Zika virus infection. 

- 25 February 2016: Authorities from Saint Vincent and the Grenadines reported the first autochthonous case of Zika virus infection. 

- 25 February 2016: Authorities of the Netherlands confirmed the first case of Zika virus infection detected in Sint Maarten.[9] 

- 26 February 2016: Authorities from Argentina reported the ongoing investigation of one case of presumed sexual transmission of Zika virus in a case with no history of travel and sexual contact with a person with symptoms of Zika virus infection and recent travel history to Colombia.  This was later confirmed on 22 March 2016

- 29 February 2016: Authorities from Panama reported one case of GBS with blood and urine samples positive for Zika virus.

- 15 March 2016: Authorities from Dominica reported the first confirmed cases of local transmission of Zika virus disease.

- 16 March 2016: Authorities from Cuba reported the first confirmed cases of local transmission of Zika virus disease.

- 18 March 2016: Authorities of Panama reported a case of microcephaly and occipital encephalocele in a newborn who died within hours after birth. Samples from the umbilical cord tested positive for Zika virus by RT-PCR. The mother had not reported history of previous illness with Zika virus and tested negative for Zika virus.

- 2 April 2016: Authorities of Colombia reported the first cases of microcephaly under investigation for Zika virus. 

- 7 April 2016: Authorities of France reported two cases of microcephaly and one fetal anomaly associated with Zika virus in Martinique.  

- 7 April 2016: Authorities from Saint Lucia reported the first confirmed cases of local vector-borne transmission of Zika virus disease.

- 29 April 2016: Authorities from Peru reported the first confirmed cases of local vector-borne transmission of Zika virus disease.

- 29 April 2016: Authorities of France reported the detection of local vector-borne transmission of Zika virus on the island of Saint Barthélemy

- 5 May 2016: Authorities from Grenada reported the first confirmed cases of local vector-borne transmission of Zika virus disease.

- 16 May 2016: Authorities from Belize reported a confirmed case of local vector-borne transmission of Zika virus disease, following the 7 April 2016 report by United States health authorities of an imported case of Zika virus disease with travel history to Belize. 

- 18 May 2016: Authorities from Argentina reported the first confirmed cases of local vector-borne transmission of Zika virus disease.

- 18 May 2016: Authorities of the United States of America reported the first case of congenital syndrome associated with Zika virus infection in Puerto Rico

- 10 June 2016: Authorities from El Salvador reported the first confirmed case of congenital syndrome associated with Zika virus infection.

- 20 June 2016: Authorities from the United Kingdom reported the first confirmed case of local vector-borne transmission of Zika virus disease in Anguilla.

- 20 June 2016: Authorities of France reported the first confirmed case of congenital syndrome associated with Zika virus infection in French Guiana.

- 18 July 2016: Authorities from the United States of America reported a confirmed case of Zika virus in a caregiver of a Zika case who died. As of 13 September, the mode of transmission is still unclear. However, patient A was known to have had close contact with the index patient while the index patient's viral load was found to be very high.[10 ]

- 29 July 2016: Authorities from the United States of America confirmed four cases of locally transmitted vector-borne Zika virus disease in Florida.

- 25 July 2016: Authorities from Antigua and Barbuda reported the first confirmed case of local transmission of Zika virus.

- 26 July 2016: Authorities from the United Kingdom reported the first confirmed cases of local transmission of Zika virus in the Turks and Caicos.

- 27 July 2016: Authorities from Paraguay reported the first two laboratory confirmed cases of microcephaly associated with Zika virus.

- 5 August 2016: Authorities from Canada reported a case of maternal-fetal transmission of Zika virus with severe neurological abnormalities. On 25 July the authorities from Canada had reported a case of maternal-fetal transmission of Zika virus where the infant appears to be generally healthy with no abnormalities detected.

- 10 August 2016: Authorities from the Bahamas reported the first confirmed cases of local transmission of Zika virus. Authorities from the United Kingdom reported the first confirmed cases of local transmission of Zika virus in the Cayman Islands.

- 10 August 2016: Authorities from Costa Rica reported the first confirmed case of Zika-virus-associated GBS.

- 11 August 2016: Authorities from Honduras reported the first confirmed case of Zika-virus-associated GBS.

- 14 August 2016: Authorities from Suriname reported the first confirmed case of congenital syndrome associated with Zika virus infection.

- 20 August 2016: Authorities from the Dominican Republic reported three microcephaly cases associated with Zika virus infection. All three cases were IgM positive for Zika.

- 23 August 2016: Authorities from Costa Rica reported one laboratory confirmed case of microcephaly associated with Zika virus infection. In addition, authorities from Haiti reported 14 cases of congenital malformation including one confirmed case linked to Zika virus infection. [11]

- 26 August 2016: Authorities from the United Kingdom reported the first confirmed cases of local transmission of Zika virus in the British Virgin Islands.

- 14 September 2016: The Guatemala Ministry of Health reported 17 confirmed cases of congenital syndrome associated with Zika virus infection. [12]

- 15 September 2016: The Lancet published the study titled "Association between Zika virus infection and microcephaly in Brazil, January to May, 2016: preliminary report of a case-control study." This preliminary analysis showed a strong association between microcephaly and laboratory confirmation of Zika virus infection. The study was the first to estimate the seroprevalence of Zika virus infection in pregnant women in an epidemic area in Brazil.

- 15 September 2016: Authorities from Saint Kitts and Nevis reported the first confirmed cases of local transmission of Zika virus disease.

- 7 October 2016: The Grenada Ministry of Health reported to PAHO/WHO the first laboratory confirmed case of congenital syndrome associated with Zika virus infection in the country.

- 23 October 2016: Authorities from Guatemala reported an increase in GBS cases, in addition to the previously reported Zika-virus laboratory in a case of GBS.

- 1 November 2016: Trinidad and Tobago reported the first laboratory confirmed case of congenital syndrome associated with Zika virus infection in the country.

- 2 November 2016: The Bolivia Ministry of Health reported the first three laboratory confirmed cases of congenital syndrome associated with Zika virus infection in the country.

- 4 November 2016: Authorities from the United Kingdom reported the first confirmed cases of vector-borne local transmission of Zika virus in Montserrat.

- 7 November 2016: The Argentina Ministry of Health reported the first laboratory confirmed case of congenital syndrome associated with Zika virus infection in the country.

- 11 November 2016: Authorities of France reported the first laboratory confirmed case of congenital syndrome associated with Zika virus infection in Guadeloupe.

- 19 November 2016: The Bolivia Ministry of Health reported the first case of GBS associated with Zika virus infection in the country.

- 6 December 2016: The Nicaragua Ministry of Health reported the first laboratory confirmed case of congenital syndrome associated with Zika virus infection in the country.

- 8 December 2016: Authorities of France reported the first confirmed case of Zika-virus-associated GBS in Saint Martin, as well as another case of neurological syndrome, both laboratory confirmed for Zika virus. 

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References:

[1] Read more here

[2] Read more here.

[3] Read more here.

[4] Read more here.

[5] Read more here.

[6] Read more here.

[7] Read more here.

[8] Read more here

[9] Sint Maarten, part of the Kingdom of the Netherlands, is a country on the southern part of a Caribbean island shared with Saint Martin, a French overseas collectivity.

[10] Read more here.

[11] Read more here.

[12] Read more here.

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Suggested citation: Pan American Health Organization / World Health Organization. Timeline of the emergence of Zika virus in the Americas, April 2016. Washington, D.C.: PAHO/WHO; 2016 Pan American Health Organization - www.paho.org - © PAHO/WHO, 2016