What are the different types of malarial parasites? Do you know them all?

Malaria is a serious and sometimes life-threatening tropical disease caused by Plasmodium and transmitted by Anopheles mosquitoes. Although my country has been certified as a "malaria-free country" by the World Health Organization, there is still a risk of malaria transmission in some border areas. When traveling abroad, especially to some African countries, there is also a risk of contracting malaria. So, what types of malaria are there and what symptoms will occur after infection?

Malaria is caused by Plasmodium, which is a parasite of five species: falciparum, vivax, ovale, malariae, and knowlesi. Plasmodium is the most widespread of these parasites, and falciparum is the parasite with the highest mortality rate. P. vivax is the most common malaria parasite outside of sub-Saharan Africa, especially in Asia and Latin America. P. falciparum is the most common malaria parasite in Africa and reproduces very quickly, causing severe blood loss and vascular blockage in infected individuals. P. falciparum can also cause serious complications, including severe anemia and end-organ damage, including coma (cerebral malaria), pulmonary complications (such as edema and respiratory syndrome), hypoglycemia, and acute kidney injury [1].

The symptoms after malaria infection are mainly divided into four periods: incubation period, chill period, fever period, and sweating period. The incubation period from human infection with malarial parasites to onset of disease is generally 14 days for vivax malaria and ovale malaria, 12 days for falciparum malaria, and 30 days for malaria malaria. Due to the different amounts, types, and methods of protozoa infection in different populations, as well as differences in human immunity, different populations will have different incubation periods. The incubation period of parasite strains in temperate regions is longer, up to 8 to 14 months; the incubation period of patients infected with malarial parasites through blood transfusion can be as short as 7 to 10 days; the incubation period of malaria transmitted from mother to child is even shorter.

After the onset of malaria, the patient will first enter the chill phase. The patient will feel chills, feel cold extremities, and feel cold all over. The patient's skin will develop goose bumps, lips and nails will turn cyanotic, the face will be pale, and the muscles and joints of the whole body will ache. The patient will experience symptoms of shivering and chattering teeth. Each attack will last for 10 minutes to an hour, after which the chills will stop and the body temperature will rise. The chills and chills are caused by the proliferation of malarial parasite schizonts in the red blood cell stage. The proliferation of schizonts causes a large number of red blood cells to rupture, releasing merozoites, various metabolites, and broken red blood cells that stimulate the body's temperature regulation center, causing dysfunction of the body's temperature regulation center. The body's temperature set point moves upward. At this time, the body's own body temperature is high, and the temperature difference with the outside world increases, so the person will feel abnormally cold and have chills [1].

After the patient has gone through the chill phase, they enter the fever phase. After the chill disappears, the patient's body temperature rises rapidly. Usually, the more severe the chill, the higher the body temperature, which can reach over 40°C. Some patients experience severe headaches, vomiting, palpitations, and thirst. The fever generally lasts for 2 to 6 hours, and in some patients it can last for more than 10 hours[1].

After the high fever, the patient begins to enter the sweating phase. The patient sweats profusely, clothes are soaked, and the body temperature drops. At this time, the patient feels comfortable and sleepy, and after falling asleep and waking up, he returns to normal, and then enters the intermittent phase [1].

In recent years, many cities in my country have found many malaria patients entering the country. Therefore, prevention of malaria is still very important. If you need to go to a country where malaria is spread, you must take more precautions and seek medical attention in time if you find any symptoms of discomfort.

References

[1] Duan Yinong. Modern Parasitology. 2nd edition. Modern Parasitology. 2nd edition, 2015