Malaria is an acute febrile infectious disease caused by protozoa transmitted by the infected female Anopheles mosquito. Anyone can get malaria. Individuals who have had multiple episodes of malaria may reach a state of partial immunity, with few or no symptoms. If not treated correctly, the disease can lead to death, however, fortunately its treatment is simple, effective and free.
Individual protection measures
Individual protection measures have as main objective to reduce the possibility of being bitten by the transmitting mosquito. Below is a list of them:
– Use curtains and mosquito nets, preferably impregnated with long-lasting insecticides, over the bed or net. In addition to being an individual protection measure, it has a vector control effect when used by most of the community involved.
– Use screens on doors and windows and, where available, air conditioning.
– Avoid going to places close to natural mosquito breeding sites, such as riverbanks or flooded areas in the late afternoon until dawn, because at these times there are a greater number of transmitters circulating.
– Minimize uncovered areas of the body where the mosquito can bite as little as possible by wearing light-coloured, long-sleeved pants and shirts.
– Use repellents based on DEET (N-N-diethylmetatoluamide) or icaridin on uncovered parts of the body. This can also be applied to clothes. The use must follow the manufacturer’s instructions in relation to the age group and the frequency of application.
What are the symptoms of malaria?
Headache, which may occur cyclically.
Many people, before presenting these more characteristic manifestations, feel nausea, vomiting, tiredness and lack of appetite.
Malaria treatment aims to eliminate the parasite from the individual’s bloodstream as quickly as possible and should be started as soon as possible after diagnosis. Immediate treatment with an antimalarial – up to 24 hours after the onset of fever – is essential to prevent complications. If the diagnostic test is not accessible within the first two hours of care, antimalarial treatment should be administered based on the patient’s clinical and epidemiological status.
WHO recommends artemisinin-based combination therapies (ACTs) for the treatment of malaria caused by the parasite P. falciparum. The combination of two active ingredients with different mechanisms of action makes ACTs the most effective antimalarial available.
Artemisinin and its derivatives cannot be used as oral monotherapy. Fixed-dose formulations (combination of two different active ingredients in a single tablet) are more recommended than using multiple tablets or capsules, as they facilitate adherence to treatment.
P. vivax infections should be treated with chloroquine in areas where the drug is still effective, such as most of Brazil, combined with primaquine to eliminate latent hepatic forms. In chloroquine-resistant areas, an ACT should be used, combined with another with a long half-life.
Treatment for severe malaria consists of injectable artesunate (intramuscularly or intravenously), followed by ACT-based treatment as soon as the patient is able to take oral medications. If injectable treatment is not possible, the patient should immediately receive artesunate intrarectally and be referred as soon as possible to a suitable location for complete parenteral treatment.
WHO recommends that national malaria control programs regularly monitor the effectiveness of drugs.
How is malaria diagnosed?
Correct diagnosis of malarial infection is only possible by demonstrating the parasite, or related antigens, in the patient’s blood by the diagnostic methods specified below:
It is the method officially adopted in Brazil for the diagnosis of malaria. Even after advances in diagnostic techniques, this test remains a simple, effective, low-cost and easy-to-perform method. When properly executed, it is considered the gold standard by the World Health Organization (WHO).
Its technique is based on the visualization of the parasite through optical microscopy, after staining with vital dye (methylene blue and Giemsa), allowing the specific differentiation of the parasites, from the analysis of their morphology, and their stages of development found. in the bloodstream.
The determination of parasite density, useful for prognostic assessment, should be performed in every patient with malaria, especially in patients with P. falciparum. Through this technique it is possible to detect other hemoparasites, such as Trypanosoma sp. and microfilariae.
– thin smear
It has low sensitivity (it is estimated that the thick smear is about 30 times more effective in detecting malarial infection). However, this method allows, more easily, the specific differentiation of the parasites from the analysis of their morphology and the changes caused in the infected erythrocyte.
Rapid tests for the detection of antigenic components of Plasmodium – immunochromatographic tests represent new methods of rapid diagnosis of malaria.
They are performed on nitrocellulose strips containing monoclonal antibody against specific parasite antigens. In cases of parasitemia greater than 100 parasites/μL, it may have a sensitivity of 95% or more when compared to the thick smear.
Most of the tests available today specifically discriminate P. falciparum from other species. Due to their practicality and ease of performance, they are useful for diagnostic confirmation, however their use should be restricted to situations where it is not possible to perform the thick smear examination by a certified microscopist with performance monitoring, such as distant and difficult areas. access to health services and areas of low disease incidence.
These tests do not assess the parasite density or the presence of other hemoparasites and should not be used for cure control, due to the possible persistence of parts of the parasite after treatment, leading to a false positive result.
The diagnostic quality of a rapid diagnostic test (RDT) depends on the experience of the examiner and the care with which it is prepared and interpreted. The performance and accuracy of TDRs can be affected by a number of factors, such as test fabrication problems, storage and shipping conditions, handler competence and performance.
Currently, the National Malaria Prevention and Control Program (PNCM) uses the SD-BIOLINE MALARIA AG Pf/Pf/Pv for malaria diagnosis, which is a combined test that works with the HRP-II and pLDH of P. falciparum and pLDH from P. vivax. It offers sensitivity for P. falciparum HRP-II of 100%, P. falciparum pLDH of 99.7% and P. vivax of 98.2% and specificity of 99.3%. Guidance on this rapid test for the diagnosis of malaria can be accessed here.
For testing, treatment and even prevention, it is necessary that the professional is wearing gloves and appropriate PPE, as otherwise he may be contaminated by the infected patient. It is also important for the patient, because if the professional has any contagious disease, he will be protected.