The Malaria or malaria , as it is known, is a well – known disease, but after an intense effort to prevent and combat the Malaria no longer a major threat to public health. In addition, it is an infectious and endemic disease (tropical and subtropical regions) caused by the existence of parasites of the genus Plasmodium in the blood and which are transmitted by the bite of female Anopheles mosquitoes.
The Malaria is characterized by periodic fever accesses; daily, every two days, or every three days, depending on the responsible plasmodium (plasmodium falciparum, plasmodium vivax, plasmodium malariae and plasmodium ovale) hepatesplenomegaly and the presence of blood parasites that invade the erythrocytes.
The Malaria may come as a disease with acute character (which can be rapidly fatal and that manifests itself in different forms, depending on the predominantly involved organ) or chronic nature (which can lead to cachexia and death).
What is malaria:
The Malaria (Malaria) is an infection caused by protozoa of the genus Plasmodium, transmitted by Anopheles mosquitoes, characterized by episodes of fever , chills and shakes. The presence of the parasite leads to the destruction of red blood cells (red blood cells) and consequent anemia .
It is still a very common disease, especially in poor countries of the tropical belt of the planet, where there is little access to preventive measures and treatment is delayed.
It is estimated that malaria kills about 660,000 people a year and there is no preventive vaccine yet. The World Health Organization (WHO) has a program to improve the condition and every year releases a report with data on the disease worldwide.
The disease is treated as a medical emergency because the delay in starting treatment allows the disease to develop until it seriously affects vital organs, including the brain.
In ICD 10 (International Classification of Diseases, tenth edition), malaria is found under codes B50 through B54, depending on the type of parasite causing the infection .
The Malaria is transmitted by the bite of the female Anopheles mosquito, infected with Plasmodium, a type of protozoan. These mosquitoes are most abundant at dusk and dawn. However, they are found stinging throughout the night, to a lesser extent.
The Malaria is not a contagious disease. That is, a sick person is not able to transmit the disease directly to another person. The vector is required to perform the transmission.
Only female Anopheles mosquitoes are capable of transmitting malaria . The incubation period of malaria varies by plasmodium species.
Once the infected mosquito bites the human, the parasites travel to the liver , where they multiply and enter the red blood cells. Within these cells, the parasites multiply rapidly until they rupture, releasing even more parasites into the bloodstream and manifesting in the process the typical symptoms of the disease.
The Malaria begins as a flu , with the first symptoms appeared between nine and 14 days after infection . Symptoms include fever (typical cycles of fever , chills, and sweating may occur ), joint pain, headache , frequent vomiting, seizures, and coma.
If simple malaria is not treated, it can become severe – about eight million cases of malaria progress to the severe type of malaria annually . Malaria deaths can occur due to brain damage (brain malaria ) or damage to vital organs. Reduction in red blood cells can cause anemia .
Causes of Malaria:
Malaria parasites belong to the genus Plasmodium (phylum Apicomplexa). In humans, malaria is caused by P. falciparum, P. malariae, P. ovale, P. vivax and P. knowlesi. Among the infected population, the most prevalent species is P. falciparum (~ 75%), followed by P. vivax (~ 20%).
Although P. falciparum is responsible for most deaths, recent data suggest that P. vivax malaria is associated with life-threatening conditions in equal numbers with P. falciparum infection .
- vivax is, by proportion, more common outside Africa. Several human infections with several species of Plasmodium of simian origin are also documented; However, with the exception of P. knowlesi – a zoonotic species that causes malaria in monkeys – the public health relevance of these infections is only residual.
Parasite Life Cycle
In the Plasmodium life cycle, the female Anopheles mosquito (the definitive host) transmits to a vertebrate (the secondary host, such as humans) a mobile infectious form (called sporozoite), thus acting as a vector.
Sporozoite travels through blood vessels to liver cells, where it reproduces asexually (through tissue schizogonia), producing thousands of merozoites. The latter will infect more red blood cells and initiate a series of asexual multiplication cycles that produce between 8 and 24 new infectious merozoites each until the cell ruptures and begins a new cycle of infection .
The remaining merozoites become immature gametocytes, which are the precursors of male and female gametes. When a mosquito bites an infected person, gametocytes are transported in the blood and mature in the digestive system of the mosquito.
The male and female gametocytes fuse and form an oocineto – a mobile fertilized zygote. In turn, ookinets become new sporozoites that migrate to the insect’s salivary glands, ready to infect new vertebrates. When the mosquito feeds on the bite, sporozoites are injected into the skin through its saliva.
Only the female mosquito feeds on blood; males feed on plant nectar and do not transmit the disease . Females of the genus Anopheles prefer to feed through the night, starting to search for a meal at sunset. Malaria parasites can also be transmitted through blood transfusions, although their occurrence is rare.
Malaria symptoms may recur after periods without any symptoms. Depending on the cause, recurrence may be classified as recurrence, relapse or reinfection. Recurrence occurs when symptoms recur after a period without any symptoms.
It is caused by parasites in the blood that have survived inadequate or ineffective treatment. Relapses occur when symptoms recur even after the parasites have been eliminated from the blood due to persistent populations of dormant hypnozoites in liver cells . Relapses often occur between 8 and 24 weeks and are more frequent in P. vivax and P. ovale infections.
In cases of P. vivax malaria in temperate regions, it is common for hypnozoites to fall asleep during winter, and relapses begin the year after the mosquito bite. Reinfection occurs when the parasite that caused the previous infection was completely eliminated from the body , but a new parasite was introduced.
It is difficult to distinguish reinfection from recrudescence, although the occurrence of a new infection within two weeks after treatment of the initial infection is usually attributed to the failure of this treatment.
The decision on how to treat the patient with Malaria should be in accordance with the Malaria Therapy Manual , issued by the Ministry of Health, and be guided by the following:
Plasmodium species depending on the species of Plasmodium the patient will receive a type of treatment.
Disease severity – due to the need for faster acting injectable drugs on parasites to reduce lethality.
The most commonly used medicines for malaria treatment are:
Only a doctor can tell you which medicine is right for you, as well as the correct dosage and duration of treatment. Always follow your doctor’s instructions strictly and NEVER self-medicate. Do not stop using your medicine without consulting a doctor first, and if you take it more than once or in much larger quantities than prescribed, follow the directions on the package leaflet.