Translated from Italian, “malaria” means “bad air”. This disease is a group of infectious diseases that can be transmitted to humans through the bite of an Anopheles mosquito. Malaria is accompanied by severe chills and fever, splenomegaly (enlarged spleen), enlarged liver. 400-500 million people become infected with malaria every year, and about 3 million die. The main causative agent of malaria are plasmodia – the simplest. For humans, only four species are pathogenic, namely, P. malariae and P. vivax, P. ovale and P. falciparum. It was found that infection occurs during injection or inoculation of a female mosquito (malaria) sporozoites into the blood or lymph system, which occurs during the process of bloodsucking.
After sporozoites enter the bloodstream, they begin to gradually penetrate the hepatocytes of the liver, thereby giving rise to the hepatic preclinical stage of the disease. At the stage of schizogony (asexual reproduction), even from one sporozoite, up to 40,000 merozoites or schizonts in the liver can arise. Usually, these merozoites enter the bloodstream after a few weeks. In those infections where the infection is caused by North African P. vivax strains, the first release of merozoites into the blood from the liver occurs, on average, in the tenth month after infection. This happens in those terms that coincide with the short-term period of the breeding of mosquitoes.
Symptoms of malaria – a fever that occurs when a malaria parasite in a human blood reaches a certain level. The lowest concentration of parasites that can cause fever is called the “pyrogenic threshold”, which is measured by the number of malaria parasites in 1 μl of human blood.
The level of the pyrogenic threshold may depend on the specific properties of the body of each person and on how strong the immune system is. In the process of infection development, with the development of immunity, this threshold rises, and those people who are newly infected with malaria will get malaria with a higher level of parasites in the blood. At the initial infection, the level of the pyrogenic threshold can range from a couple of tens in 1 μl of blood, and in people who are ill again, or in partially immune people who came from a malarial area, the threshold is at the rate of several thousand malaria parasites in one μl of blood .
Types of Malaria
Four forms of the disease are distinguished: a three-day form, four-day malaria, oval malaria, and tropical.
All these forms are characterized by their own characteristics, but the general characteristics for each species are the presence of fever, anemia, and enlargement of the liver and spleen.
Three day malaria
Before the onset of the malaria attacks themselves, a headache , weakness, nausea, and sharp back pain appear . The disease begins acutely. In the early days, the fever is wrong. After this, an intermittent-type fever is established, with a constant alternation of malaria attacks every other day. A malaria attack is characterized by a pronounced change in the main stages of heat and chills, and there is increased, excessive sweating. The heat lasts about four to six hours, however, there are cases when the heat lasts up to twelve hours and is replaced by a sharp sweating.
This type of malaria is similar to three-day malaria, but the main difference is the milder course of oval malaria, in contrast to three-day malaria. Feverish attacks can occur every other day, and mainly in the evening. Relapses can be early and distant. The disease can last from three to four years.
Four day malaria
The spleen is enlarged moderately, in rare cases, anemia can develop. This form of the disease is characterized by a very low parasitemia, even at those moments when malaria is acute. Four-day malaria is characterized by a long course, from five to fifty years. During this time, plasmodia “live” in human blood, where a weak process of schizogony of an erythrocytic character proceeds.
The incubation period can be at least a week, however, it can take up to two weeks. By the end of the incubation period, prodromal phenomena in the form of malaise and headache, fatigue begin. Vomiting and nausea, loss of appetite and chills are possible. An irregular type of fever occurs. Tropical malaria differs from other species in that it does not have chills and increased sweating characteristic of malaria, pain in the joints and muscles is practically absent.
How to prevent malaria?
Methods that it is important to use to prevent the development and widespread spread of the disease in areas that are endemic for malaria should include both medicines and the destruction of mosquitoes, the development of tools to protect against malicious bites. To date, a malaria vaccine has not yet been developed.
RECOMMENDATIONS FOR PEOPLE PLANNING DEPARTURES TO THE REGION,
WHERE MALARIA IS DISTRIBUTED
* Apply measures to protect against mosquito bites.
* Take drugs for the prevention of malaria before leaving the outbreak, the entire period of stay in the outbreak in the season when there is a risk of infection, and within 4 weeks after departure.
* Get acquainted with possible adverse reactions when taking antimalarial drugs and contraindications for their use.
* Learn the symptoms of malaria and be prepared for a possible disease, despite taking medications to prevent malaria.
It is necessary to have drugs for three courses of treatment for malaria when staying in the outbreak for 6 months. Always carry drugs in case emergency care is not possible.