Symptoms of Plasmodium infection

There are many types of malarial parasites, and some of them may parasitize on people and many parts of the body. Once infected, patients will often feel different changes and manifestations. First, it will cause adverse reactions in the body, the body will become larger, and it may even cause bacterial infection. The specific symptoms have not yet been clearly determined, and the corresponding diagnosis must be made based on the cause of the development of the disease.

Basic Introduction

There are many types of malarial parasites. There are four types of malarial parasites that parasitize humans, namely Plasmodium vivax (Grassi and Felletti, 1890) Labbe, 1899, Plasmodium falciparum (Welch, 1897) Schaudinn, 1902, Plasmodium malariae (Laveran, 1881) Grassi and Felletti, 1890, and Plasmodium ovale Stephens, 1922, which cause vivax malaria, falciparum malaria, malariae malaria and ovale malaria, respectively. In my country, the main parasites are Plasmodium vivax and Plasmodium falciparum. Plasmodium malariae is rare and Plasmodium ovale is even rarer. form

The basic structure of the malarial parasite includes the nucleus, cytoplasm and cell membrane. The subsequent stages of the ring body also contain the final product of digestion and decomposition of hemoglobin - hemoglobin. After the blood smear is stained with Gibbs or Wright's stain, the nucleus is purple-red, the cytoplasm is sky blue to dark blue, and the hemochromatin is brown, tan or dark brown. The four types of human malarial parasites have the same basic structure, but their morphologies at different stages of development are different, which can be used to identify them. In addition to the different morphological characteristics of the malarial parasites themselves, the parasitized red blood cells may also undergo changes in morphology. Whether there are changes in the morphology of the parasitized red blood cells and the characteristics of the changes are very helpful in identifying the species of Plasmodium.

Main forms

Three developmental stages

Plasmodium grows, develops, and reproduces inside red blood cells, and its morphology changes greatly. There are generally three main developmental stages.

(1) Trophozoite: The stage in which the malarial parasite feeds, grows and develops inside red blood cells. According to the order of development, trophozoites can be divided into early and late stages. The early trophozoite has a small nucleus, little cytoplasm, a vacuolar cell in the middle, and the body is mostly ring-shaped, so it is also called a ring form. Later, the worm grows larger, the nucleus also increases, the cytoplasm increases, pseudopodia sometimes extend, and malarial pigment begins to appear in the cytoplasm. Red blood cells infected with Plasmodium vivax and Plasmodium ovale can become larger, deformed, and lighter in color, often with obvious red Schuffner's dots; red blood cells infected with Plasmodium falciparum have thick purple-brown Maurer's dots; red blood cells infected with Plasmodium malariae may have Ziemann's dots. This is called the late trophozoite, also known as the large trophozoite.

(2) Schizont: When the late trophozoite matures and the nucleus begins to divide, it is called a schizont. The nucleus divides repeatedly, and finally the cytoplasm divides as well. Each nucleus is wrapped by part of the cytoplasm and becomes a merozoite. The early schizont is called an immature schizont, and the late schizont containing a certain number of merozoites and in which the hemochromatin has been concentrated into clusters is called a mature schizont.

(3) Gametocyte: After several rounds of fission and proliferation, some merozoites invade red blood cells and grow larger. Their nuclei become larger and no longer divide, their cytoplasm increases and they have no pseudopodia. Finally, they develop into round, oval or crescent-shaped individuals, called gametocytes. Gametocytes are divided into female and male (or large and small): female (large) gametocytes are larger, with dense cytoplasm, abundant and coarse hemochromatin, and dense nuclei that are biased to one side of the body or in the center; male (small) gametocytes are smaller, with thin cytoplasm, less and smaller hemochromatin, and loose, larger nuclei located in the center of the body.