Despite all of man's efforts to tame nature, nature often fights back. That fight can take unexpected forms. For example, a deadly tapeworm living inside your brain.
A recent article in Scientific American revealed that neurocysticercosis, a disease caused by a brain parasite common in developing countries around the world but rare in the United States, has increasingly become prevalent in California.
While the disease is preventable by practicing basic good hygiene and simple to treat if discovered early on in the process, since the condition is relatively rare in the United States, it often goes undiagnosed until it becomes potentially life-threatening.
A study published in the Journal of Neglected Tropical Diseases found that in 2009, California saw 304 cases of neurocysticercosis. Additionally, Californians comprised a full 60 percent of all fatalities resulting from the condition.
The vast majority of the affected population, just under 85 percent, was Latino, and most cases occurred in Southern California. Medical costs from treating neurocysticercosis topped $17 million in the state in 2009 alone.
The study notes that the number of hospitalizations from the condition has remained essentially stable from a decade ago.
Throughout the developing world, it's an entirely different story. An estimated 29 million people may have have contracted the parasite solely in Latin America.
"Nobody knows exactly how many people there are with it in the United States," says [Theodore] Nash, who is the chief of the Gastrointestinal Parasites Section at NIH. His best estimate is 1,500 to 2,000. Worldwide, the numbers are vastly higher, though estimates on a global scale are even harder to make because neurocysticercosis is most common in poor places that lack good public-health systems. “Minimally there are 5 million cases of epilepsy from neurocysticercosis," Nash says.
He puts a heavy emphasis on minimally. Even in developed nations, figuring out just how many people have the illness is difficult because it is easy to mistake the effects of a tapeworm for a variety of brain disorders. The clearest proof is the ghostly image of a cyst in a brain scan, along with the presence of antibodies against tapeworms.
The tapeworm's eggs typically enter the body by way of uncooked, contaminated pork. While they can grow up to 20 feet long in pigs, the parasites never develop past the larval stage in humans and are only about the size of a pea. However, by virtue of their small size, the larva don't just stay in the gut. They can move throughout the entire body, even the brain.
After the tapeworm larvae comes in, it uses a chemical process to block the host's immune system from attacking while it feeds. As a result, someone can live with the parasite inside them for years without experiencing many ill effects.
But that's just the beginning.
"While it's alive, it's a problem, but when it starts to die it's a bigger problem," microbiologist Dickson Despommier told Scientific American.
Despommier explained that, after the larvae die, the immune system suddenly recognizes the invader and starts to fight, resulting in symptoms like seizures, blinding pain, paralysis, coma and even death.
Praziquantel, a drug that kills any tapeworm larvae living in the brain, was developed in the 1980s; however, it has a whole host of side effects that can exacerbate the swelling of brain tissue.
Gizmodo notes that, as a result of the risks associated with the treatment, most experts in the field are now focusing on preventive measures such as vaccinating pigs agains the worm and administering specific medications.