21 de março, 2024 Autor: Saraiva da Cunha Malaria continues to be an important cause of morbidity and mortality in some areas of the world . It is more characteristic of tropical regions, especially in Africa, where in 2022 there were 94% of the 249 million global cases and 95% of the 608 thousand deaths due to malaria, affecting mainly children under 5 years of age. Cause and transmission of malaria Malaria is caused by a parasite and is transmitted by a mosquito. There are five species of the parasite that causes malaria, two of which are particularly important: Plasmodium falciparum is the dominant species in sub-Saharan African countries and causes the most serious infections, which can quickly result in death if left untreated; Plasmodium vivax predominates in other countries; The remaining three species, and less important ones, are Plasmodium malarie, Plasmodium ovale and Plasmodium knowlesi . The parasite that causes malaria is transmitted by female Anopheles mosquitoes that are infected by the parasite, when they bite and feed on human blood. Malaria is not usually transmitted between people, except when a blood transfusion occurs from an infected patient or when a pregnant woman transmits the disease to her fetus. The disease can be prevented and can be treated, as long as it is identified in time. Prevention Controlling mosquitoes and preventing their bites is the basis of malaria prevention. This prevention includes: Sanitary measures implemented by the authorities in each country, aimed at the environment and local populations; Individual measures, being each one of responsible to adopt it. The individual protection measures to be adopted, especially by travelers, are: Use mosquito nets to protect beds or other place where sleeping; Sleep only in rooms with windows and doors protected against the entry of mosquitoes; Wear clothing that leaves as little skin exposed as possible: long sleeves, long pants, closed shoes, for example; Regularly apply mosquito repellent: On exposed skin areas and possibly on clothing; Reinforce the application at dawn and dusk, when mosquitoes are most active; Choose the repellent according to the instructions given, since the mosquitoes that transmit malaria are resistant to some products. Try not to stay outdoors at dawn and dusk. Anyone traveling to countries where there is malaria, and to tropical countries in general, should make a traveler's consultation in advance (4-6 weeks in advance). Malaria prevention may also include taking medication, which the doctor will choose depending on the country of destination and individual risk and characteristics. Depending on the medicine selected, malaria prevention may need to start around 3 weeks before the trip and only end a few weeks after return. Having had malaria does not mean that you are immune to the disease. Therefore, whenever traveling to high-risk countries, prevention measures continue to be necessary. Symptoms and treatment Malaria has varying severity. The disease may only have mild symptoms, but it can also cause death, especially when it affects risk groups such as: Children under 5 years old; Pregnant women; Travelers, who did not adopt preventive measures, in areas where the disease is endemic; People infected with the human immunodeficiency virus (HIV). Symptoms of malaria begin on average 10-15 days after the mosquito bite that transmitted the infection, but the incubation period can vary between 7 and 30 days. Therefore, it is not uncommon for a traveler who has not taken adequate precautions to begin of the disease after returning to their country. And, even taking all the recommended prevention, including medication, it is possible to have malaria. The first symptoms may be mild and non-specific, such as fever, headaches, body aches, chills and sweating. Therefore, during the first 2-3 months after returning from a trip to areas at risk of malaria, it is necessary to be aware of symptoms and seek medical care when they arise, reporting the history of recent travel, including dates and destinations. Only then it will be possible to perform the necessary tests trying to identify the parasite and to treat the disease properly, if diagnosed. Among the most serious symptoms of malaria are, for example: Marked fatigue Loss of appetite, nausea and vomiting Difficulty breathing Bloody or dark urine Jaundice Seizures Confusion / hallucinations Changes in the state of consciousness The global goal The World Health Organization strategy for malaria established among its objectives to reduce the incidence and mortality of malaria by at least 75% and 90%, in the years 2025 and 2030, respectively. In the same years, to eliminate the disease in 20 and 35 of the countries where it was transmitted in 2015. In Portugal In our country, malaria has been eradicated since 1973. The last case of confirmed transmission in Portugal occurred in 1959. Until then, malaria transmission occurred mainly in the regions of the Sado Valley, Mondego and Vouga, that are important rice culture areas, whose characteristics favored the concentration of mosquitoes. Measures to control these vectors were decisive in eradicating the disease. Malaria is a notifiable disease in Portugal and cases continue to be diagnosed every year but originating outside the country. In 2018, the last year for which data for this disease are published in Portugal: 101 cases of malaria were diagnosed 86% (87 cases) occurred in men The most affected age group, with 25 cases, was 45-54 years old. Sources: Serviço Nacional de Saúde. Doenças de notificação obrigatória – Malária World Health Organization - Malaria 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.
