What Is a Hydatid Cyst?

Hydatid disease is a zoonotic parasitic disease caused by the larvae of Echinococcus parasites in humans. It is endemic and is called endemic parasitic disease. It is characterized by occupational damage in endemic areas and is classified as an occupational disease in certain populations. Globally, it is a common disease unique to ethnic minorities or religious tribes. And frequently-occurring ^[1] .

The worm body is pale red, 10-50 cm long. The mature somite is 7 mm in length and 2 to 3 mm in width. It has a long oval shape and looks like cucumber seeds. Every mature

Echinococcus granulosus must rely on two mammalian hosts to complete its life cycle. Dogs are the most important final host, and wild predators such as wolves, jackals, and foxes can also be their final hosts. Intermediate hosts are mainly artiodactyl animals such as sheep, cattle, and pigs. They can also infect wild herbivores, kangaroos and rodents. Animals. Although humans are good intermediate hosts for Echinococcus granulosus, they are usually only victims and do not participate in the life history cycle. Some ethnic minorities have the habit of burial and water burial. At this time, people may also participate in the cycle of the worm's life history. ^[4]

This disease is an animal-derived disease, which not only endangers human health, but also severely harms livestock. Sheep infection rate is very high. In severe cases, the production of meat, wool, oil, milk and other livestock products will be reduced, causing huge losses to the livestock economy ^[5]

Hydatid disease is a disease caused by human infection with larvae of Echinococcus, so it is also called Echinococcus disease. The disease is spread all over the world, and it is a common parasitic disease in livestock areas such as Gansu, Ningxia, Qinghai, Xinjiang, Shaanxi, Inner Mongolia and western Sichuan. Among human ascariasis, the disease is the most serious ^[6]

The clinical manifestations of hydatid disease vary depending on its parasitic site, cyst size, and the presence or absence of complications. There may be no symptoms at an early stage, and the general health of the patient is good. In general, the course of cystic hydatid disease progresses slowly, with an incubation period of 1 to 30 years. Most patients are often asymptomatic and found during physical examination or surgery for other diseases, and some patients are found at autopsy after death. As the cysts gradually grow, the symptoms of space-borne compression and systemic toxicity of the parasitic site become apparent. Clinically, the corresponding hydatid disease is named according to the organs parasitic to Echinococcus ^[7]

1. It is mainly prevalent in livestock areas and has a history of close contact with dogs and sheep ^[8]

Immunoprevention

Hydatid disease should be based on prevention. At present, cysts are mainly removed by surgery ^[9] .

Immunization is an ideal way to prevent the epidemic of hydatid disease. Screening and cloning of effective immunogenic components of Echinococcus granulosus using modern molecular biology techniques to prepare genetically engineered vaccines has opened up a new approach for the prevention and diagnosis of hydatid disease ^[10] .

Foreign countries have achieved satisfactory results in controlling the epidemic of hydatid disease. The excretion or secreted product of Echinococcus granulosus in vitro cultured in vitro is used as an antigen, and the sheep can obtain high immunity against Echinococcus granulosus eggs after vaccination, which proves that Hexococcus granulosus can produce host protective antigen . At present, some researchers have used the EG95 recombinant protein vaccine to immunize echinococcus granulosus to infect intermediate hosts (sheep), and achieved relatively satisfactory results. The study found that the intermediate host (sheep) immunized with the EG95 recombinant protein vaccine can obtain good immune protection (96% ~ 98%), and can effectively resist different fine-grained Echinococcus strains (New Zealand strain, Australian strain and (Argentina strain) infection, reducing the incidence of hydatid disease ^[10] .

Hydatids circulate in the body (2 photos)