Paragonimus Westermani - a food-borne lung fluke prevalent in Eastern Asia and South America.
Lifecycle
The Paragonimus Westermani has a very complex life cycle, which passes through 2 intermediate hosts before reaching the human. Embryos originate from human feces, where they then seek the first intermediate host, a snail. After developing inside the snail, the worm is released into the second host, which are usually crabs or crayfish.
At this point, the fluke is infective and can be transferred to humans when these infected fish are consumed raw. In humans, the worms burrow their way to the lungs and can last up to 20 years, and every 65-90 days, the worm will produce new eggs.
Symptoms
The acute phase is the initial infection and migration through the body. Common symptoms during this phase include: diarrhea, abdominal pain, fever, cough, urticaria, hepatosplenomegaly, pulmonary abnormalities, and eosinophilia
The chronic phase begins once the fluke has reached the lungs. Symptoms of this stage include: coughing, expectoration of discolored sputum, hemoptysis, and chest radiographic abnormalities. More severe symptoms can appear depending on if the worm has burrowed into other places besides the lungs (like the brain).
Spread
The Paragonimus Westermani's life cycle starts with the defecation into soil or rivers or by coughing fits by infected humans. Fortunately, there is no way to directly transfer the disease between humans - the eggs themselves are not known to enter human hosts and cause disease.
Prevention
The main prevention method centers around avoiding eating raw crab or crayfish. Crabs and crayfish should be cooked properly, to 145 degree Fahrenheit and can easily be accomplished by educating the populace, giving sustainable means to properly cook fish. However, in Asia, this may go against their cultural norms.
Another option is via drugs as effective drug treatments also exists.
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