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I HEARD THAT “BOVINE CYSTICERCOSIS”, “PORCINE CYSTICERCOSIS” COULD BE TRANSMITTED INTO HUMAN? WHAT ARE THEY? I AM A PIG STOCKPERSON, AM I EXPOSED TO THE RISK OF ACQUIRING THESE?
(A stockperson in Thanh Hoa province)
There is nothing as delighted as a slightly cold morning in Thanh Hoa, sitting in front of a bowl of “Pho”, you will enjoy the delicious soup without any awareness of danger lurking into undercooked pork or beef. Let’s see, what is the risk?
Both beef and pork may be infected with "cysticercosis" (this is an encysted larval form of two different kinds of flukes). If the beef is infected with cysticercosis, scientifically named Cysticercus bovis, and porcine cysticercosis is called Cysticercus cellulosae.
Bovine cysticercosis was named after the shape of many rice-like cysts within bovine muscle tissue, white or pale yellow, consisting of a single inverted scolex. This is the larvae of Taenia saginata tapeworm parasite in the intestine of humans. Bovine is the intermediate host, while human is the definitive host.
Similarly, porcine cysticercosis, also shapes like rice, 6-15mm long and 3-5mm wide. Inner layer is transparent fluid covered by a thin film outer layer, which contains a white dot call scolex. Larvae of Taenia solium tapeworm live in the intestine of humans. Pig is the intermediate host, while human is the definitive host. The life cycle of Taenia solium is similar to the life cycle of Taenia saginata.
HOW IS PORCINE, BOVINE "CYSTICERCOSIS" FORMATION?
Pigs and cattle become infested when ingesting food or water contaminated with eggs or gravid segments of Taenia solium and Taenia saginata, respectively. Contamination of cattle feed can occur through undue defecation of humans in the pastures or stables, but also indirectly through irrigation with contaminated human sewage. The eggs can remain infective for several months.
Once ingested by cattle the young larvae hatch out of the eggs in the gut, go through the intestinal wall, reach the blood stream and migrate to lympho node and organs, where they encyst. The cyst can find in diaphragm, intercostal muscles, iliocostalis muscle, neck muscle, and tongue after 40 to 50 days. The cysts need 2 to 4 months to complete development in cysticercosis. Pigs and cattle are intermediate hosts so that they only show subclinical signs.
HOW TAPE WORMS INFECT OR CYST FORM IN HUMAN?
In humans there are two circumstances can occur:
First: Humans become infected when eating insufficiently cooked meat contaminated with cysts. Once in the human stomach, the cysts will destroy external layer and release the young tapeworm, which attach to the gut's wall and develop to adult after only 2-3 months. Adult Taenia solium can be approximately 2-7m long while Taenia saginata length is approximately 4-10m. Adult worms produce 1,000 tapeworm segments, each contains approximately 50,000 eggs. Adult worms survive in the intestine for years.
People infected with tapeworms may have clinical signs include abdominal pain, vomiting, nausea, itching around the anus, depression, dizziness, headache, diarrhea or constipation, poor appetite, weight loss.
Second: Human can also contract tapeworms via ingest contaminated food or water, or self-infect. Self-infection, or autoinfection, is a phenomenon when reverse peristalsis stimuli bring back fluke’s eggs or segments into the stomach from the small intestine in a person already infected with Taenia solium. Eggs ingested or due to self-infection will parasite on the gut and then migrate to tissues, brain, liver and other tissues in the body. They will develop into "cysticercus". Cysticercosis affect human seirously if "cysticercoses" are localized in brain, which can result in seizures and death.
HOW TO PREVENT "PORCINE CYSTICERCOSIS" AND " BOVINE CYSTICERCOSIS "?
Cysticercoid can be destroyed when stored at -100C temperature for 10 days (home refrigerators cannot reach this point). So it is best to prevent by:
1. Only eat well-cooked food and drink boiled water, avoid undercooked meat not only to prevent cysticercosis but also other diseases that can be transmitted from animals to humans.
2. Wash your hands thoroughly with soap before eating.
3. Do not defecate in the field but in toilet.
The information presented above shows that “porcine cysticercosis" and " bovine cysticercosis" can only be transmitted to humans via eating undercooked contaminated beef and pork, while exposure during rearing procedures do not cause any harm. Therefore, don’t worry about this and keep on your work. Wish you full of health and success!
Assoc.Prof. LÊ VĂN THỌ
(A stockperson in Thanh Hoa province)
There is nothing as delighted as a slightly cold morning in Thanh Hoa, sitting in front of a bowl of “Pho”, you will enjoy the delicious soup without any awareness of danger lurking into undercooked pork or beef. Let’s see, what is the risk?
Both beef and pork may be infected with "cysticercosis" (this is an encysted larval form of two different kinds of flukes). If the beef is infected with cysticercosis, scientifically named Cysticercus bovis, and porcine cysticercosis is called Cysticercus cellulosae.
Bovine cysticercosis was named after the shape of many rice-like cysts within bovine muscle tissue, white or pale yellow, consisting of a single inverted scolex. This is the larvae of Taenia saginata tapeworm parasite in the intestine of humans. Bovine is the intermediate host, while human is the definitive host.
Similarly, porcine cysticercosis, also shapes like rice, 6-15mm long and 3-5mm wide. Inner layer is transparent fluid covered by a thin film outer layer, which contains a white dot call scolex. Larvae of Taenia solium tapeworm live in the intestine of humans. Pig is the intermediate host, while human is the definitive host. The life cycle of Taenia solium is similar to the life cycle of Taenia saginata.
HOW IS PORCINE, BOVINE "CYSTICERCOSIS" FORMATION?
Pigs and cattle become infested when ingesting food or water contaminated with eggs or gravid segments of Taenia solium and Taenia saginata, respectively. Contamination of cattle feed can occur through undue defecation of humans in the pastures or stables, but also indirectly through irrigation with contaminated human sewage. The eggs can remain infective for several months.
Once ingested by cattle the young larvae hatch out of the eggs in the gut, go through the intestinal wall, reach the blood stream and migrate to lympho node and organs, where they encyst. The cyst can find in diaphragm, intercostal muscles, iliocostalis muscle, neck muscle, and tongue after 40 to 50 days. The cysts need 2 to 4 months to complete development in cysticercosis. Pigs and cattle are intermediate hosts so that they only show subclinical signs.
HOW TAPE WORMS INFECT OR CYST FORM IN HUMAN?
In humans there are two circumstances can occur:
First: Humans become infected when eating insufficiently cooked meat contaminated with cysts. Once in the human stomach, the cysts will destroy external layer and release the young tapeworm, which attach to the gut's wall and develop to adult after only 2-3 months. Adult Taenia solium can be approximately 2-7m long while Taenia saginata length is approximately 4-10m. Adult worms produce 1,000 tapeworm segments, each contains approximately 50,000 eggs. Adult worms survive in the intestine for years.
People infected with tapeworms may have clinical signs include abdominal pain, vomiting, nausea, itching around the anus, depression, dizziness, headache, diarrhea or constipation, poor appetite, weight loss.
Second: Human can also contract tapeworms via ingest contaminated food or water, or self-infect. Self-infection, or autoinfection, is a phenomenon when reverse peristalsis stimuli bring back fluke’s eggs or segments into the stomach from the small intestine in a person already infected with Taenia solium. Eggs ingested or due to self-infection will parasite on the gut and then migrate to tissues, brain, liver and other tissues in the body. They will develop into "cysticercus". Cysticercosis affect human seirously if "cysticercoses" are localized in brain, which can result in seizures and death.
HOW TO PREVENT "PORCINE CYSTICERCOSIS" AND " BOVINE CYSTICERCOSIS "?
Cysticercoid can be destroyed when stored at -100C temperature for 10 days (home refrigerators cannot reach this point). So it is best to prevent by:
1. Only eat well-cooked food and drink boiled water, avoid undercooked meat not only to prevent cysticercosis but also other diseases that can be transmitted from animals to humans.
2. Wash your hands thoroughly with soap before eating.
3. Do not defecate in the field but in toilet.
The information presented above shows that “porcine cysticercosis" and " bovine cysticercosis" can only be transmitted to humans via eating undercooked contaminated beef and pork, while exposure during rearing procedures do not cause any harm. Therefore, don’t worry about this and keep on your work. Wish you full of health and success!
Assoc.Prof. LÊ VĂN THỌ
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