Parasites parasitize in the cells, tissues or lumens of the host, causing a series of damages, not only found in protozoa, adult worms, but also in migrating larvae, their role in the host is multifaceted.
(1) Capture nutrition
The substances required for the parasite to grow, develop and reproduce in the host are mainly derived from the host, and the more parasitic insects, the more nutrients are captured. For example, aphids and mites parasitize in the intestines, take a large amount of nutrients, and affect the intestinal absorption function, causing host malnutrition; and hookworms attached to the intestinal wall to absorb a large amount of blood, can cause the host anemia medical education network to collect and organize.
(2) Mechanical damage
Parasites can cause damage or oppression to the parasitic parts and nearby tissues and organs. Some parasites, especially individuals, are large and the number is very serious. For example, aphids can be twisted into a mass to cause intestinal obstruction. The hydatid of the hydatid is in the liver. At first, there is no obvious symptom. Later, it gradually grows and presses the liver tissue and other organs in the abdominal cavity, and obvious compression symptoms occur. In addition, migration of larvae in the host can cause serious damage. For example, aphid larvae can break through the alveolar wall capillaries when they move in the lungs, which can cause bleeding.
(3) The role of toxicity and antigenic substances
Parasite secretions, excretions, and decomposition products of dead insects have toxic effects on the host, which is the most important type of parasite hazard host. For example, when E. histolytica invades the intestinal mucosa and liver, it secretes lytic enzymes, dissolves tissues and cells, causes ulceration of the intestinal wall of the host and liver abscess; the secretion and excretion of the aphid of the broad-segmented aphid may affect the hematopoietic function of the host. anemia. In addition, the metabolites of the parasite and the decomposition products of the dead worm are antigenic, which can sensitize the host and cause local or systemic allergic reactions. For example, the secretion of oocysts in the oocysts causes immunopathological changes in the surrounding tissues - granuloma of the eggs, which is the most basic disease of schistosomiasis and the main cause of the disease. In addition, the antigenic substance of Plasmodium forms an immune complex with the corresponding antibody, deposits on the basement membrane of the glomerular capillary, and causes glomerulonephritis with the participation of complement. As well as the rupture of the wall of the thorn ball, the cystic fluid enters the abdominal cavity, which can cause anaphylactic shock or even death in the host.
(4) Hypersensitivity reaction
Parasites in the host often induce hypersensitivity reactions in the host, causing tissue damage. This is one of the pathogenic effects of parasites. Hypersensitivity reactions are generally classified into four types, namely type I, II, III, and IV. The first three types are antibody-mediated hypersensitivity reactions, and type IV is mainly hypersensitivity mediated by T cells and macrophages. These four hypersensitivity reactions are also called immediate hypersensitivity reaction, cytotoxic hypersensitivity reaction, immune complex hypersensitivity reaction and delayed type hypersensitivity reaction.
Human parasite prevention method
1. Although not all meat has parasites, most parasites can indeed be killed by high temperatures. Therefore, if it is not a very safe ingredient, please do not eat it or cook it, or raw food. When cooking meat, pay attention to the heat. If you want to cook the meat, you would rather cook it, and don't be half-baked.
2. In the process of growing vegetables and fruits, it may be due to the application of animal manure. The parasites are mainly excreted by the excrement of the animal's feces, and washed several times in order to prevent the remaining eggs.
3. Raw and cooked to be separated, cut the meat knife, and then cut onions and parsley, etc., onions and parsley we generally cooked up to sprinkle, which also gave the parasite a way of life.
4. Cut the chopping board after the meat, it is best to wash with detergent, every other time, hot with hot water. Cut the fruit's chopping board is also best separated from the cut meat.
5. Wash hands before and after meals.Similarly, because many parasites are excreted through the feces, it is important to wash your hands after a break, especially for children.