ZIKA VIRUS (ZIKV) CLASSIFICATION TABLE DATA AS OF 16 NOVEMBER 2017
Table 1. ZIKV classification1,2 WHO Regional Office Country / territory / subnational area Total AFRO Angola; Guinea-Bissau 2 Anguilla; Antigua and Barbuda; Argentina; Aruba; Bahamas; Barbados; Belize; Bolivia (Plurinational State of); Bonaire, Sint Eustatius and Saba; British Virgin Islands; Costa Rica; Cuba; Curaçao; Dominica; Dominican Republic; Ecuador; El Salvador; French Guiana; Grenada; Guatemala; Category 1: Area with AMRO/PAHO Guyana; Honduras; Jamaica; Montserrat; Nicaragua; Panama; new introduction or 40 Paraguay; Peru; Puerto Rico; Saint Kitts and Nevis; Saint Lucia; Saint re-introduction with Martin; Saint Vincent and the Grenadines; Sint Maarten; Suriname; ongoing transmission Trinidad and Tobago; Turks and Caicos Islands; United States of America; United States Virgin Islands; Venezuela (Bolivarian Republic of) Marshall Islands; Micronesia (Federated States of); Palau; Samoa; WPRO 7 Singapore; Solomon Islands; Tonga Subtotal 49 Category 2: Area Burkina Faso; Burundi; Cabo Verde; Cameroon; Central African AFRO 10 either with evidence Republic; Côte d’Ivoire; Gabon; Nigeria; Senegal; Uganda of virus circulation AMRO/PAHO Brazil; Colombia; Haiti; Mexico 4 before 2015 or area SEARO Bangladesh; India; Indonesia; Maldives; Thailand 5 with ongoing transmission that is no longer in the new Cambodia; Fiji; Lao People's Democratic Republic; Malaysia; Papua or re-introduction WPRO 7 New Guinea; Philippines; Viet Nam phase, but where there is no evidence of interruption Subtotal 26 Category 3: Area with Cayman Islands; Guadeloupe; ISLA DE PASCUA – Chile; Martinique; AMRO/PAHO 5 interrupted Saint Barthélemy transmission and with American Samoa; Cook Islands; French Polynesia; New Caledonia; potential for future WPRO 5 Vanuatu transmission Subtotal 10 Benin; Botswana; Chad; Comoros; Congo; Democratic Republic of the Congo; Equatorial Guinea; Eritrea; Ethiopia; Gambia; Ghana; Guinea; Kenya; Liberia; Madagascar; Malawi; Mali; Mauritius; Mayotte; AFRO 33 Mozambique; Namibia; Niger; Réunion; Rwanda; Sao Tome and Principe; Seychelles; Sierra Leone; South Africa; South Sudan; Togo; Category 4: Area with United Republic of Tanzania; Zambia; Zimbabwe established Uruguay 1 competent vector but AMRO/PAHO EMRO Djibouti; Egypt; Oman; Pakistan; Saudi Arabia; Somalia; Sudan; Yemen 8 no known Georgia; Região Autónoma da Madeira – Portugal; Russian Federation; documented past or EURO 4 Turkey current transmission SEARO Bhutan; Myanmar; Nepal; Sri Lanka; Timor-Leste 5 Australia; Brunei Darussalam; China; Christmas Island; Guam; Kiribati; WPRO Nauru; Niue; Northern Mariana Islands (Commonwealth of the); 12 Tokelau; Tuvalu; Wallis and Futuna Subtotal 63 Total 148 Category 1: Area with new introduction or re-introduction with ongoing transmission
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Areas are classified according to country, territory, or subnational area. http://apps.who.int/iris/bitstream/10665/254619/1/WHO-ZIKV-SUR-17.1-eng.pdf
1
A laboratory-confirmed autochthonous,3 vector-borne case of ZIKV infection in a country /territory/subnational area where there is no evidence of virus circulation before 2015, whether it is detected and reported by the country /territory/subnational area where infection occurred, or by another country by diagnosis of a returning traveller; or b. A laboratory-confirmed autochthonous, vector-borne case of ZIKV infection in a country/territory/subnational area where transmission has been previously interrupted, whether it is detected and reported by the country where infection occurred, or by another country by diagnosis of a returning traveller. Category 2: Area either with evidence of virus circulation before 2015 or area with ongoing transmission that is no longer in the new or re-introduction phase, but where there is no evidence of interruption This category takes into account those countries with known historical laboratory evidence of ZIKV circulation prior to 2015, based on the literature as well as all ZIKV surveillance data whether detected and reported by the country where infection occurred or by another country reporting a confirmed case in a returning traveller. Countries in this category may have seasonal variations in transmission. These countries may also experience outbreaks of ZIKV disease. Laboratory criteria to ascertain the presence of ZIKV in past studies are: a. Detection of the virus in humans, mosquitoes or animals; and/or b. Serologic confirmation of ZIKV infection with tests conducted after 1980, and considered as confirmed infection on expert review based on testing for all appropriate cross-reactive flaviviruses and utilization of comprehensive testing methodologies. Because of testing and interpretation limitations with serological data antedating 1980, they were not used for classification purposes. Category 3: Area with interrupted transmission and with potential for future transmission The minimum timeline for determining transition to an interrupted state is 12 months after the last confirmed case, and no cases identified in travellers. For countries with a high capacity for diagnostic testing, consistent timely reporting of diagnostic results, a comprehensive arboviral surveillance system and/or a temperate climate or island setting, the interruption of vector-borne transmission is defined as the absence of ZIKV infection 3 months after the last confirmed case. Countries where interruption is epidemiologically likely to have occurred should provide surveillance data to WHO to support the assessment by expert review. Category 4: Area with established competent vector but no known documented past or current transmission All countries/territories/subnational areas where the main competent vector (A. aegypti) is established, but which have not had a documented, autochthonous, vector-borne case of ZIKV infection. This category also includes a subgroup of countries/territories/subnational areas where ZIKV transmission may occur because of a shared border with a neighbouring Category 2 country, by belonging to the same ecological zone and having evidence of dengue virus transmission. In this subgroup, a first laboratory-confirmed, autochthonous vector-borne case of ZIKV infection may not necessarily indicate new introduction (Category 1), but rather previously unknown and undetected transmission (Category 2), and these countries/territories/subnational areas will be reclassified accordingly. a.
3
Autochthonous infection is considered to be an infection acquired in-country, i.e. among patients with no history of travel during the incubation period or who have travelled exclusively to non-affected areas during the incubation period.
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