Zika Outbreaks

Zika Outbreaks 2025

Zika virus disease (ZIKV) was first recognized in Uganda in 1947. According to the World Health Organization (WHO), Zika outbreaks have been noted in the region of the Americas since 2007 and will continue in 2025. Autochthonous (local) mosquito-borne transmission of ZIKV has been detected in 92 countries and territories globally. Studies predict that 1.3 billion people could be impacted by Zika by 2050. The United States, the United Kingdom, and Canada list countries that account for about 95% of Zika cases between 2014 and 2024.

Congenital Zika Syndrome

The 2015–2016 ZIKV outbreak in the Region of the Americas revealed the ability of ZIKV from the Asian lineage to cause birth defects, generically called congenital Zika syndrome (CZS), which may cause severe birth defects of the brain and eyes, including severe microcephaly. A study published in Pediatrics in January 2025 concluded children exposed to ZIKV in utero, even without CZS, demonstrate a greater risk for neurodevelopmental delay in early childhood, with the timing of maternal infection being a significant predictive risk factor. The International Journal of Infectious Diseases published a study in 2025 showing children with CZS will have more frequent hospitalizations in early childhood. Scientists have reported that ZIKV RNA is detectable in the semen of infected men for months and is found in newborn children.

Zika in the United States

As of December 31, 2024, the U.S. CDC reported 19 non-congenital Zika cases in U.S. residents (1 imported case in Texas). The CDC says Zika-spreading mosquitoes are found throughout Puerto Rico, where the Department of Health says 16 cases were reported in 2024. In 2023, the U.S. CDC reported five non-congenital cases in U.S. residents and 27 in U.S. territories.

Zika Outbreaks The Americas

As of 2025, the Pan American Health Organization (PAHO) confirmed local transmission of Zika in countries and territories in the Region of the Americas. As of January 15, 2025, 2 Zika cases were reported in the Americas in 2025. The PAHO has reported over 42,127 ZIka cases and two related fatalities in the Americas in 2024, with the highest proportion of Zika cases reported in Brazil, Bolivia, Columbia, and Costa Rica. In December 2024, Brazil's Ministry of Health published weekly Zika case reports, indicating over 40,000 cases in 2024 and 35,962 in 2023. The PAHO reported over 37,659 Zika cases in the Americas in 2023.

Zika in Asia

Since 2016, the Zika virus has been reported in India's 16 different states/union territories. In December 2024, there had been 148 AES cases, including 59 deaths in 2024. Those infected also included 63 pregnant women. The most affected Indian states are Maharashtra, Kerala, Chickballapur, and Karnataka. In 2024, the U.K. stated travelers should practice usual precautions when visiting India's Zika outbreak areas, such as Maharashtra and Madhya Pradesh. In August 2024, the U.S. CDC issued a Level 2 - Practice Enhanced Precautions regarding an ongoing Zika outbreak in Maharashtra.

The Kingdom of Cambodia's Ministry of Health confirmed its first case of the Zika virus since 2016. Thailand reported 742 Zika virus infections in 2023,160, of which zero were recorded in Bangkok. This is a significant increase from the 190 cases reported in 2022. Singapore reported 30 cases of Zika in 2023. The female Aedes aegypti mosquito is Singapore's primary vector of Zika.

Zika in Europe

The European Centre for Disease Prevention and Control (ECDC) says the Zika virus is not endemic in mainland Europe. In November 2024, Italy reported 7 imported Zika cases this year. On September 11, 2024, France reported five imported cases of Zika in 3 departments colonized by Aedes albopictus. In 2022, the European CDC reported that 31,453 Zika patients were confirmed in 13 of 52 countries and territories. In addition, the WHO reported in 2019 that French authorities confirmed an autochthonous Zika virus case in Hyeres, Var department.

Zika Pacific Islands

As of May 2024, anti-ZIKV antibodies were found in 66% of the Cook Island test collective and 52% of the Vanuatu specimens. As of October 2023, the Solomon Islands reported 7 Zika cases.

Zika Thailand

Thailand has seen ongoing Zika transmission into 2024, with 148 confirmed cases reported as of December, following the high levels of transmission from 2023, when 777 cases were reported in Thailand.

Zika United Kingdom

As of December 2024, 8 Zika virus cases were reported between January and June 2024. This UKHSA data represents a 700% increase compared to the same period in 2023. Thailand (5 cases) and Singapore (2) were the most frequently reported travel countries. The U.K. Health Security Agency (UKHSA) issued a warning on March 21, 2024, concerning Zika outbreaks. Travel-related Zika cases in the U.K. peaked in 2016 with 725 cases.

Zika Virus and Dengue

A study published in Science Translational Medicine on May 29, 2024, found that primary ZIKV infection increased the risk of disease caused by DENV3 and DENV4 but not DENV1. This was also true for tertiary infections when individuals were previously infected with DENV and then ZIKV, but not when they were previously infected with ZIKV and then DENV.

Zika Virus Infections

According to the WHO, there is scientific consensus that the Zika virus is transmitted to people by mosquitoes of the genus Aedes. The WHO says two Zika virus lineages, the African lineage and the Asian lineage, have recently spread in the Pacific and the Region of the Americas. Zika infections can cause microcephaly, Guillain-Barré syndrome (GBS), and other central nervous system malformations. Although the Zika outbreak in southern Brazil has slowed in recent years, live births with microcephaly continue to be reported.

The U.S. Centers for Disease Control and Prevention (CDC) published Research, Volume 30, Number 2—February 2024: temporal phylogenetic analysis revealed limited within-host diversity among most ZIKV-persistent infected associated samples. The researchers detected unusual virus temporal diversity, uncovering the existence of divergent genomes within the same patient. During pregnancy, healthcare providers can monitor the fetus for signs of congenital Zika virus infection, says the CDC.