In the investigation, the reporter found that the versions of hookworm pork rumors in many places are basically the same from words to pictures, but the place names are different. As for the pictures spread by online rumors, it was verified that they first appeared in a pork parasite rumor in Guangxi last year (165438+ 10), and the "hookworm" shown in the pictures was not parasites at all after verification by relevant units.
Red Net Zhangjiajie Station (Zhangjiajie Online) reminds the general public and friends to treat online rumors with a scientific attitude.
"According to our current test results, hookworms have not been found in pork, because this adult parasite can't reach muscle tissue and can't survive in muscle tissue, let alone see live worms." Director Qu of Zhangjiajie Animal Disease Control Center said, "And there are no parasites that can't be cooked, fried and killed at high temperature."
Hookworm is the general name of hookworm, and the developed oral sac is its morphological feature. Among the nematodes parasitic in human digestive tract, hookworm is the most harmful. Due to hookworm parasitism, it can cause long-term chronic blood loss, leading to anemia and anemia-related symptoms in patients. Hookworms are distributed all over the world, especially in tropical and subtropical areas, and human infection is more common. It is estimated that the number of hookworm infections worldwide is about 900 million. In China, hookworm disease is still one of the parasitic diseases that seriously endanger people's health.
The hookworm parasitic on human body mainly includes hookworm duodenum (1843), which is called hookworm duodenum for short; Necator American stiles (1902) is short for American hookworm. In addition, Ceylonia (19 1 1), which occasionally parasitizes humans, is similar to the first two hookworms.
Larvae infected by dogs (Hookworm Ercolani, 1859) and Brazil (Hookworm Gomez de Faria, 19 10) can invade human body and cause larval migration (CLM). Because the larvae migrate zigzag and the rash is crawling, it is called crawling rash. But larvae cannot develop into adults.
2 morphological feature editing
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It is about 1 cm long, translucent, fleshy red, and grayish white after death. The worm has a thin front end and a well-developed mouth sac at the top, which is composed of tough keratin.
Dog intestines infected with hookworm
Composition. Because the front end of the worm bends backward, the upper edge of the oral sac is the ventral surface and the lower edge is the dorsal surface. The duodenal sac of hookworm is oblate, and there are two pairs of hook teeth on the abdominal edge. The external teeth are generally slightly larger than the internal teeth, and there is a semi-circular deep recess in the center of the back side and slight protrusions on both sides. The oral sac of hookworm is oval. Its belly edge has 1 pair of plate teeth, and its back edge has 1 pair of conical sharp teeth. The length of the pharyngeal tube of hookworm is about 1/6 of its body length, the posterior end is slightly enlarged, and the pharyngeal tube wall is muscular. The intestinal wall is thin, consisting of a single layer of epithelial cells with fine villi on the inner wall, which is beneficial to the absorption and diffusion of oxygen and nutrients.
There are three kinds of unicellular glands in hookworm: ① 1 head gland, which is located on both sides of the worm, with the front end connected with the head sensilla, opening in the head sensilla holes on both sides of the oral sac, and the back end reaching the front and back of the worm's midline. The head gland mainly secretes anticoagulant and acetylcholinesterase. Anticoagulant is a kind of heat-resistant non-enzymatic polypeptide, which has antithrombin effect, prevents coagulation of intestinal wall wound of host, and is beneficial to hookworm blood feeding. The secretion of the head gland is controlled by nerves.
American hookworm mouth sac
System; ② Three pharyngeal glands are located in the wall of pharyngeal duct, and their main secretions are acetylcholinesterase, protease and collagenase. Acetylcholinesterase can destroy acetylcholine, affect the transmission of nerve mediators, reduce the peristalsis of the intestinal wall of the host, and facilitate the attachment of worms. Quantitative cytochemical analysis showed that the content of acetylcholinesterase in hookworm was higher than that in hookworm duodenum. ③ There are 1 pairs of excretory glands, which are cystic and free from the ventral side of protozoa, reaching 1/3 after the worm. The gland is connected with the transverse excretory duct, and the secretion is mainly protease.
The male reproductive system of hookworm is single-tube, and the end of male worm is enlarged, which is a membranous copulating umbrella formed by horny extension. The mating umbrella consists of two lateral leaves and 1
Conjugated umbrellas and spines of hookworm duodenale and hookworm americana.
It consists of 10 dorsal leaves with muscular finger spokes, which are called dorsal spokes, lateral spokes and abdominal spokes respectively according to their positions. The branching characteristics of dorsal radial rib are one of the important basis for identifying insect species. The male has a pair of mating spines. Female insects have conical ends, some species have tail spines, the reproductive system is double-tube, and the vulva is located in the middle or front and back of the insect's ventral surface.
According to the shape of the worm, the characteristics of the oral sac, the shape of the male copulatory umbrella and its dorsal radial ribs, the shape of the copulatory spines, the presence or absence of the female tail spines and the position of the vulva, etc. The morphological identification points of hookworm duodenale and hookworm americana are shown in the following table.