June 13, 2024 Author: Saraiva da Cunha Zika fever, infection or disease is caused by the Zika virus, which is a flavivirus. Its name comes from the place where it was first identified in 1947: the Zika forest, in Uganda. The first outbreaks of Zika fever occurred in 2007 in Africa and on Micronesian islands in the Pacific Ocean. During the following years, other outbreaks were repeated on the Pacific islands and in 2014 the first cases of Zika were identified in Brazil. Since then, several cases have been diagnosed on the American continent and in Europe, both in people who had traveled to regions of the world where the virus is endemic and also locally transmitted infections. In Portugal, the first cases of Zika – 21 – were diagnosed in 2016. In 2017, a case was diagnosed in a child under 1 year of age and a new case was reported in 2020. Zika virus transmission Like the virus which cause yellow fever, dengue, Japanese encephalitis, among others, the Zika virus is an arbovirus, which means it is transmitted by arthropods, in this case mosquitoes. Aedes aegypti is the main transmitting species , but Aedes albopictus also plays an important role, especially outside tropical regions, such as Portugal. These mosquitoes in human habitats , lay eggs in natural or artificial water accumulations and fly short distances. The infected mosquito females transmit the virus , when they bite to feed on blood, which they need to complete their biological cycle. When they are not infected and bite a person infected with the Zika virus, they can become infected and transmit the disease to other people. Mosquitoes which transmit zika bite during the day, especially at dawn and dusk. In the case of the Zika virus, there are other known forms of transmission: By contact, mainly sexual . In infected people, the virus survives in semen for a long time and also in vaginal fluids. It can be transmitted during vaginal, anal or oral sex. Transmission can occur even when there are no symptoms or after they have disappeared. From mother to child during pregnancy and childbirth , with serious consequences, for example: Congenital microcephaly Seizures Physical and cognitive development disorders Difficulty swallowing Balance, mobility, vision and hearing disorders Symptoms and diagnosis Zika virus infection may not cause any symptoms. In most people, it is mild and self-limiting, that is, it resolves on its own, usually within 4 to 7 days. Zika symptoms are not specific , the most common being: Low fever Headaches Joint pain Conjunctivitis, with redness, tearing, eyelid edema, sensitivity to light and pain in the eye area Rash on the skin of the face, which can spread across the body Malaise and general weakness Nausea and vomiting, abdominal pain and changes in intestinal transit may also occur, but are rare. Suspicion of Zika is raised when there are symptoms and history of recent travel to areas where the virus exist or sexual relations with someone who has traveled to these places . To confirm the diagnosis, it is necessary to identify the virus in the blood or urine. Although rare, cases of serious neurological complications associated with this infection have been reported. Zika fever treatment There is no specific treatment for Zika fever. Treatment is symptomatic and includes: Medicines, usually paracetamol; Supportive measures, mainly rest, balanced diet and increased fluid intake to prevent dehydration. Zika prevention measures Currently there is no vaccine against the Zika virus , although clinical trials are underway to find one. Prevention of the disease is carried out with measures aimed at controlling the mosquito population and with individual care. Therefore, it is important in areas where there are mosquitoes: Avoid going outdoors in periods when mosquitoes are most active. Use protective nets on windows. Use fans and air conditioning , which contribute to protection because insects move away from the wind. Choose clothing carefully to cover areas of the body when outdoors , using socks and closed shoes, long sleeves, long pants and a hat. Apply insect repellents to all exposed skin (except around the eyes and mouth) and also to clothing, always following the product's instructions, particularly regarding the age range of people on which they can be used. Eliminate any stagnant water near homes , including swimming pools, buckets of water, potted plant dishes, among others, as these are the places where female mosquitoes lay their eggs. Prevention measures are especially important concerning pregnancy : Pregnant women should not travel to areas of the world where the disease exists. If their partner has traveled to these areas, they should abstain from sexual intercourse or always use condoms throughout the pregnancy, even if there are no symptoms of illness. Furthermore, when traveling to risk areas: Couples who want to get pregnant must wait six months after their return. Sources: Direção Geral da Saúde. Zika . 2023. Yuill TM. Infeção por virus Zika. 2023 Manual MSD. Versão para profissionais de saúde. Wolford RW, Schaefer TJ. Zika Virus . 2023. Treasure Island: StatPearls Publishing. European Centre for Disease Prevention and Control. Zika virus disease. Annual Epidemiological Report for 2021. Stockholm: ECDC; 2023. Meet the Infectious Diseases clinical team at the Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
