Parasites in the brain, cysticercosis, neurocysticercosis, parasites, parasites in brain, brain parasites

Did you catch that mention of Parasites in the Brain (Neurocysticercosis) tonight on tv? What are Parasites in the Brain Neurocysticercosis? On Grey’s Anatomy tonight, Archer grows ill, Addison rushes him into CT scan. And there they are – worms on the brain.

What is cysticercosis?

Cysticercosis is an infection caused by the pork tapeworm, Taenia solium. Infection occurs when the tapeworm larvae enter the body and form cysticerci (SIS-tuh-sir-KEY) (cysts). When cysticerci are found in the brain, the condition is called neurocysticercosis (NEW-row SIS-tuh-sir-KO-sis).
Where is cysticercosis found?

The tapeworm that causes cysticercosis is found worldwide. Infection is found most often in rural, developing countries with poor hygiene where pigs are allowed to roam freely and eat human feces. This allows the tapeworm infection to be completed and the cycle to continue. Infection can occur, though rarely, if you have never traveled outside of the United States. Taeniasis and cysticercosis are very rare in Muslim countries where eating pork is forbidden.
How can I get cysticercosis?

By accidentally swallowing pork tapeworm eggs. Tapeworm eggs are passed in the bowel movement of a person who is infected. These tapeworm eggs are spread through food, water, or surfaces contaminated with feces. This can happen by drinking contaminated water or food, or by putting contaminated fingers to your mouth. A person who has a tapeworm infection can reinfect themselves (autoinfection). Once inside the stomach, the tapeworm egg hatches, penetrates the intestine, travels through the bloodstream and may develop into cysticerci in the muscles, brain, or eyes.

Parasites in the Brain?

At a recent evening lecture at the California Institute of Technology, a neurologist was explaining the ins and outs of new brain-imaging technology to an audience composed of Caltech professors, students, and members of the general public. The audience was rather quiet, lulled by the technical tone of the lecture. But when the neurologist mentioned in passing that the disease afflicting one of his patients was caused by a brain parasite, the whole room sat up and made a collective noise of disgust and alarm. Brain parasites!

But, in fact, parasites infect us all the time. They live in our bodies, even in our cells, and most of the time we do not even know that they are there. The brain can provide a pleasant, nurturing environment for parasites, because it has structures that prevent many of the immune system’s cells from entering, at least in the early stages of infection. Add to that plenty of oxygen and nutrients, and the brain seems like a rather nice place to live.

Despite its seemingly idyllic home, a brain parasite’s life does have its hardships. To begin with, the parasite has to find a way into the brain. Invasion of any organ is difficult, but the brain is an especially tough nut to crack due to a protective barrier between the bloodstream and brain fluid, called the blood-brain barrier. This barrier is made up of cells that make a tight seal along any blood vessels so that most stuff from the bloodstream (including brain parasites) can’t leak into the brain. If the parasite does manage to successfully enter the brain, it then has to deal with the attack of the immune system. The cells of the immune system act together to rid the body of any foreign organisms. In humans, the immune system is highly organized and efficient; parasites’ evasion mechanisms have evolved to be good enough to thwart the immune system, at least for a little while. Unfortunately, the most effective parasites are the ones we really have to worry about.

In fact, millions of people worldwide are infected by these efficacious brain parasites. If you haven’t heard about them before, it is probably because most infected people live in nonindustrialized countries, where living conditions are not very sanitary. Many of these brain parasites cause debilitating conditions and sometimes even death. So, in addition to being interesting biologically, brain parasites are also important in the context of human disease.

Two parasites with disease-causing capabilities are the pork tapeworm, Taenia solium, and the amoeba Naegleria fowleri. In addition to their medical importance, these two organisms illustrate the many ways that brain parasites are able to affect their hosts through their methods of invasion and survival.

Parasites in the Brain?

At a recent evening lecture at the California Institute of Technology, a neurologist was explaining the ins and outs of new brain-imaging technology to an audience composed of Caltech professors, students, and members of the general public. The audience was rather quiet, lulled by the technical tone of the lecture. But when the neurologist mentioned in passing that the disease afflicting one of his patients was caused by a brain parasite, the whole room sat up and made a collective noise of disgust and alarm. Brain parasites!

But, in fact, parasites infect us all the time. They live in our bodies, even in our cells, and most of the time we do not even know that they are there. The brain can provide a pleasant, nurturing environment for parasites, because it has structures that prevent many of the immune system’s cells from entering, at least in the early stages of infection. Add to that plenty of oxygen and nutrients, and the brain seems like a rather nice place to live.

Despite its seemingly idyllic home, a brain parasite’s life does have its hardships. To begin with, the parasite has to find a way into the brain. Invasion of any organ is difficult, but the brain is an especially tough nut to crack due to a protective barrier between the bloodstream and brain fluid, called the blood-brain barrier. This barrier is made up of cells that make a tight seal along any blood vessels so that most stuff from the bloodstream (including brain parasites) can’t leak into the brain. If the parasite does manage to successfully enter the brain, it then has to deal with the attack of the immune system. The cells of the immune system act together to rid the body of any foreign organisms. In humans, the immune system is highly organized and efficient; parasites’ evasion mechanisms have evolved to be good enough to thwart the immune system, at least for a little while. Unfortunately, the most effective parasites are the ones we really have to worry about.

In fact, millions of people worldwide are infected by these efficacious brain parasites. If you haven’t heard about them before, it is probably because most infected people live in nonindustrialized countries, where living conditions are not very sanitary. Many of these brain parasites cause debilitating conditions and sometimes even death. So, in addition to being interesting biologically, brain parasites are also important in the context of human disease.

Two parasites with disease-causing capabilities are the pork tapeworm, Taenia solium, and the amoeba Naegleria fowleri. In addition to their medical importance, these two organisms illustrate the many ways that brain parasites are able to affect their hosts through their methods of invasion and survival.

source: http://eands.caltech.edu/articles/LXVI4/brainworms.html

Why Do Parasites Live In The Brain?

Different parasites choose to make their home in different places in the body. Some worms prefer the environment of the digestive system, while certain flukes thrive in the tissues of the lungs. Other parasites, like the pig tapeworm, Taenia solium, make their way to the brain to live and multiply. The brain is filled with oxygen and nutrients, and it also has structures in place that prevent the immune system from attacking parasites in the initial stages of infection. This makes for an inviting home for brain parasites!
How Do Parasites Get Into The Brain?

Most brain parasites must make a rather long journey in order to make their home in the brain. In addition, the brain can be a difficult place to invade due the protective barrier between the bloodstream and brain fluid, called the blood-brain barrier. This barrier between the blood and the fluid in the brain is comprised of cells that form a tight seal around the blood vessels that bring nutrients to and from the brain. This makes it difficult (but not impossible) for parasites and other toxins to enter the brain.

When parasite numbers become overwhelmingly large, or when a deficiency exists in the systems of the brain, parasites can make the leap from the bloodstream to the fluids of the brain. So scientists speculate that brain parasites may release an enzyme that dissolves a portion of the blood brain barrier which allows the parasite to enter.
Which Parasites Can Infect The Brain?

There are two known brain parasites, the pork tapeworm, Taenia solium, and the amoeba Naegleria fowleri.

Taenia solium: The pig tapeworm, Taenia solium, is responsible for the condition known as neurocysticercosis, the most common brain parasitic infection. Neurocysticercosis affects more than fifty million people all over the world, and it is the leading cause of brain seizures. This disease develops when larvae from Taenia solium enter the body via the ingestion of diseased pork meat. Once inside the body, the tapeworm migrates to the small intestine and remains there until it reaches maturity. From here the parasite makes its way to the brain where it attaches either to the brain tissues or to the cavities within the brain.

The parasite will then form cystic lesions that can also affect the eyes, muscles and spinal cord. The exact location of the cysts will determine the symptoms of the disease. Brain parasites can interrupt the normal activity of the brain and cause brain seizures. On the other hand, parasites that attach to the brain-fluid cavities will cause symptoms such as headaches, nausea, and dizziness, as well as brain seizures. These additional symptoms may occur because the parasite is interrupting the normal flow of brain fluid within the brain. Over time, this blockage of fluid may cause pressure to build up that can lead to permanent brain damage.

Naegleria fowleri: Unlike the pork tapeworm, Naegleria fowleri brain parasites have only infected about 175 people in the world; therefore it is not as easily known or understood. This brain parasite causes a condition called primary amoebic meningo-cephalitis. Of the 175 cases of this disease that have been reported, only six patients have survived. For this reason, scientists are eagerly searching for more answers as to these particular brain parasites can be treated.

Naegleria fowleri is an amoeba that is commonly found in the wild, especially in warm freshwater lakes and ponds. It can also survive in heated swimming pools. This parasite can infect a human host that is swimming in contaminated waters by attaching to the inside of its host’s nose and then traveling up the nose and into the brain. Once in the area of the brain, the amoeba releases an enzyme that allows it dissolve the host’s tissues, and enter the tissues of the brain. Naegleria fowleri can then into feast on the valuable nutrients with the neurons of the brain. This is why this particular parasite causes such rapid death.

In addition to the brain damage caused by destroying the brain’s neurons, the presence this parasite can also cause inflammation of the tissues within the brain. This inflammation can lead to additional brain damage and even death.

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