Zika Outbreaks 2023
Zika virus (ZIKV) is transmitted to people by mosquitoes of the genus Aedes, according to the World Health Organization (WHO). Zika virus disease cases have been noted since 2007. Since an outbreak in Brazil in March 2015, and as of 2023, the Pan American Health Organization (PAHO) has confirmed local transmission of Zika in countries and territories in the Region of the Americas. Ten countries account for about 89% of Zika cases recorded between 2014 and 2023. The PAHO reported over 31,780 Zika cases across the Americas as of December 2023, with the highest proportion of Zika cases reported in Brazil, Bolivia, Belize, Columbia, Paraguay, and Venezuela. The WHO's EPI-WIN digest #7 overviews the Zika virus disease resurgence as of September 2023. The UK TravelHealthPro says all travelers to countries where ZIKV is known to occur are at risk of infection, although determining the actual level of risk is complex.
Zika in Asia
Since 2016, the Zika virus has been reported in India's 16 different states/union territories. In November 2023, the Zika virus was found in mosquitoes in Talakayalabetta village in Sidlaghatta taluk, India, and one woman was infected in Pune. ZKV infection has been reported in a 5-year-old girl involved in Karnataka (Raichur district). According to media reports in November 2023, ten Zika cases have been confirmed over three years. The journal Frontiers in Microbiology published original research in June 2022 indicating that the Zika virus had spread to several states in India and that there was an urgent need to strengthen surveillance.
Zika in Central America
The PAHO reported in 2023 that Belize, Guatemala, El Salvador, and Mexico confirmed Zika cases in 2023. Costa Rica's Ministry of Health confirmed in September 2023 there have been 27 Zika cases confirmed this year. In 2022, there were 45 Zika cases reported in Costa Rica.
Zika in Europe
In 2022, the European CDC reported that 31,453 Zika patients were confirmed in 13 of 52 countries and territories. In Europe, two imported Zika virus infections were confirmed by the Hungary National Reference Laboratory of Viral Zoonoses of the National Center for Public Health on February 27, 2023. The two infected persons had previously been to Thailand. In addition, the WHO reported in 2019 that French authorities confirmed an autochthonous Zika virus case in Hyeres, Var department.
Zika South America
As of December 2023, the PAHO dashboard indicates over 30,132 Zika cases have been reported in Brazil this year. In 2022, about 34,000 Zika cases and four deaths were reported in Brazil. There was a 92% increase compared to the same period in 2021. There have been no related fatalities from Zika in 2022. Although the Northeast (Rio Grande do Norte) and Southeast regions were likely to continue to have the highest total infection numbers, consistency-weighted, population-standardized rates highlighted hotspot states within all five regions in Brazil, reported the CDC.
Studies conducted in the states of Rio de Janeiro and São Paulo also indicated that temperature influenced the distribution patterns of Ae. aegypti and Ae. albopictus, influencing disease transmission. There are slight differences (from 0.7 to 2.6 ∘C) in the average temperature between the high-risk and no-risk areas for Zika infections. Banu et al. showed that an increase of 1 ∘C could be related to a future rise in arbovirus cases.
Furthermore, according to Brazilian authorities, more than 1,638 babies have been born with microcephaly-related defects since 2014. The Arbovirus Surveillance Strengthening Project launched in Brazil in 2022. From 2015 to 2020, 3,591 cases of CZS were confirmed in Brazil, with an incidence of 44.03 cases per 1,000 live births and a specific mortality of 12.35 deaths per 1,000 live births.
Zika Pacific Islands
As of October 2023, the Solomon Islands reported 7 Zika cases in 2023.
Zika United States
The U.S. Centers for Disease Control and Prevention (CDC) says because the mosquitoes that spread Zika are found throughout Puerto Rico, people living on the island who have not already been infected are at risk for severe infection. In addition, the Puerto Rico Department of Health says Zika will continue to infect people in 2023. Puerto Rico's Weekly Report Arboviral Diseases #44 shows 43 probable Zika cases as of 2023 and 20 cases during 2022. In 2021, the CDC confirmed (2) Zika travel-associated and (32) local cases in U.S. territories.
Zika Virus Transmission
Zika is primarily spread by the bite of a mosquito infected with the virus, but it can also be passed during sex from a person infected with Zika to a sexual partner, says the CDC. About 25% of infected people may develop Zika symptoms, and the illness is usually mild, lasting between two and seven days, according to the CDC. Congenital Zika-associated syndrome (CZS) is a set of congenital anomalies seen in infants born to mothers with a history of gestational Zika fever, who have microcephaly as the most prevalent clinical sign. According to an April 2023 study, although microcephaly is the most severe manifestation observed in 1.5% of children at birth, severe microcephaly is less frequent. Furthermore, even though some children are born with an average head circumference, they may develop postnatal microcephaly. The Puerto Rico Department of Health (PRDH) and the U.S. CDC conducted a population-based survey of women who gave birth to a live infant from August to December 2016. This survey determined there are no known ways to prevent the adverse effects of Zika infection during pregnancy. Still, pregnant women can protect themselves from Zika infection in several ways.
Zika Virus History
The Zika virus was first isolated in 1947 in the Zika forest in Uganda (Africa). Since then, Zika has caused small, sporadic outbreaks in Africa, Asia, and South America. In 2007, a large epidemic was described on the Island of Yap (Micronesia), where about 75% of the population was infected. In 2014, Chile notified the WHO of indigenous transmission of Zika virus fever on Easter Island. Then, in May 2015, public health authorities in Brazil confirmed the transmission of the Zika virus.
As of 2023, there are no approved Zika vaccines.