Cysticercosis: what is it, the reasons. symptoms. treatment, prognosis

What is cysticercosis?

Cysticercosis is a rare infectious disease caused by the presence and accumulation of tapeworm larval cysts (cestodes) in body tissues. The scientific name for tapeworm that causes cysticercosis is pork tapeworm or pork tapeworm (lat. Taenia solium), which is also known as the armed tapeworm.

Pork tapeworm cysts (cysticercus) can affect any area of ​​the body, including the brain, causing a condition known as neurocysticercosis. Symptoms vary from case to case. If cysticercus is in the brain, central nervous system disorders can occur, most often epilepsy and headaches. Cysticercosis can also affect the eyes, spinal cord, skin, and heart.

Signs and symptoms

Symptoms of cysticercosis vary from case to case, depending on the number and location of cysticerci in the body. Cysticercus is often found in muscle tissue. In some cases, cysts develop in the brain, eyes, or heart tissue. Some people with cysticercosis are asymptomatic (i.e., asymptomatic) or have very mild symptoms and signs.

Many people with cysticercosis have damage to the central nervous system (neurocysticercosis). However, many people with neurocysticercosis do not show symptoms. The specific symptoms of neurocysticercosis depend on the number and location of the cysts involved, as well as the response of the person's immune system.

There are four main types of neurocysticercosis:

1. parenchymal;
2. subarachnoid;
3. intraventricular;
4. spinal.

Symptoms common to all forms of neurocysticercosis include headaches, epilepsy, and congestion of excess cerebrospinal fluid (CSF) in the skull (hydrocephalus), which causes increased pressure on the brain tissue, resulting in various symptoms, including:

• headaches;
• nausea;
• vomiting;
• dizziness;
• vision changes

In some cases, people who develop hydrocephalus often develop optic disc edema in turn. Swelling of the optic nerve head can cause opacity or double vision.

The parenchymal form of the disease may be associated with:

• headaches;
• epilepsy;
• intellectual disabilities;
• behavioral changes;
• hydrocephalus.

In this form of neurocysticercosis, there can also be a violation of the ability to coordinate voluntary movements (ataxia) and muscle weakness on one side of the body (hemiparesis).

Subarachnoid cysticercosis is associated with chronic inflammation of the lining of the brain, headaches, epilepsy, and hydrocephalus. Intraventricular cysticercosis can cause obstructive hydrocephalus. A variant of the form of cysticercosis known as racemic cysticercosis may occur. Racemic cysticercosis is characterized by the accumulation of cysts at the base of the brain, which can potentially lead to mental deterioration, coma, and life-threatening complications. Cysts affecting the spinal cord are rare but can lead to meningitis or spinal cord compression.

In some cases, people can experience severe central nervous system infections that can lead to life-threatening complications such as stroke or coma (cysticercolic encephalitis). People with severe central nervous system infections often first develop muscle pain (myalgia), weakness, and fever.

When cysts form in the eyes, ocular cysticercosis occurs. Associated symptoms may include:

• Pain in the eyes;
• loss of vision;
• Separating the nerve-rich membrane lining the eyes (retina) from its main supporting tissue (retinal detachment).

In some cases, cysticercosis can affect only the eyes (isolated ocular cysticercosis).

In some cases, cysts form under the skin, causing small lumps. These lumps usually don't cause any additional symptoms.

Causes and risk factors

Cysticercosis results from the ingestion of the eggs of a tapeworm known as pork tapeworm. Eating contaminated pork usually results in an adult tapeworm infection (teniasis) rather than cysticercosis.

The normal life cycle of pig tapeworms is as follows: The pig swallows tapeworm eggs. In the intestine of a pig, eggs hatch and dig through the intestinal wall into muscle tissue. There they emerge and develop into larval cysts called cysticercus. When a pig dies and a human eats its meat, the cysticercus is released and attached to the intestinal wall, where they turn into eggs, producing adult tapeworms. The condition is known as teniasis and usually does not cause any symptoms. However, people with teniasis can develop cysticercosis because those infected will shed eggs through feces and potentially swallow eggs (autoinfection). These people may also regurgitate Taenia solium eggs from the intestines into the stomach.

Cysticercosis usually occurs when a person eats food, especially pork contaminated with T. solim (not maggots). The eggs travel through the bloodstream, eventually ending up in muscles, subcutaneous cells, the brain, and other tissues in the body. After 60-90 days, eggs hatch and develop into larval cysts (cysticercus). Cysts remain in the tissues of the body indefinitely, unable to move to the next stage of their life cycle. As long as these larvae remain alive, they appear to be able to "mask" themselves from the host's immune system, causing only mild symptoms. Ultimately, however, the larvae die off, triggering a strong immune defense against him or the surrounding cyst. The cyst itself can become huge. Such inflammatory reactions can lead to serious illness, especially if the cysts are in the central nervous system or heart.

Affected populations

Cysticercosis affects men and women in equal numbers. Some forms of cysticercosis, such as racemic cysticercosis, are more common in women.

Cysticercosis is most common when people live in close contact with pigs. Thus, high prevalence rates are found in Mexico, Latin America, West Africa, Russia, India, Pakistan, Northeast China and Southeast Asia. In Europe, the disease is most common among the Slavic peoples.

Diagnostics

The diagnosis of cysticercosis can be made on the basis of a thorough clinical assessment, a detailed history of the patient, and various specialized tests. Magnetic resonance imaging (MRI) and computed tomography (CT) are used to diagnose neurocysticercosis. photo above).

Treatment

In many cases, people with asymptomatic cysticercosis do not need treatment.

When symptoms are present, people are often treated with medication or surgery.

For the treatment of cysticercosis, the antiparasitic drug albendazole (Nemozole) is used.

Before the development of albendazole, the antiparasitic drug praziquantel (biltricide) was often used to treat people with the disease. Adult tapeworm infection can be eliminated with antiparasitic drugssuch as niclosamide or paronomycin.

Seizures, sometimes associated with neurocysticercosis, can be treated with anticonvulsants such as phenytoin (dilantin) or lorazepam (ativan).

Various surgical therapies can be used to treat some people with cysticercosis. Hydrocephalus can be treated by inserting a tube (shunt) to drain excess cerebrospinal fluid (CSF) from the brain to another part of the body. Surgical removal of cysts (cysticercus) may be performed in certain cases. Cysticercus affecting the eyes can also be removed surgically.

Other treatments are symptomatic and supportive.

Forecast

Most patients with parenchymal cysticercosis either remain asymptomatic or develop a self-limited seizure disorder.

Among patients who develop intracerebral calcification, most have recurrent seizures if they are not treated with anticonvulsants. With anticonvulsant treatment, seizures are usually easily controlled.

Once infected, patients become immune to reinfection.

Globally, as of 2010, the disease was responsible for about 1200 deaths, up from 700 in 1990. According to 2010 estimates, cysticercosis killed at least 50,000 people worldwide every year.

Control and preventive measures

For the prevention, control and potential elimination of T. solium requires appropriate public health interventions covering aspects such as animal health, human health and the environment. For T. solium, various combinations of eight types of control measures can be carried out, depending on the conditions in specific countries:

• mass prescription of drugs against teniasis;
• identification and treatment of cases of teniasis;
• health education, including food hygiene and safety;
• sanitation;
• improved pig breeding practices;
• anthelmintic treatment for pigs (oxfendazole at a dosage of 30 mg / kg - a commercially available and registered agent for the treatment of cysticercosis in pigs);
• pig vaccination (TSOL18 vaccine - available on the market);
• strengthening of veterinary and sanitary control of meat and meat processing.

There remains a lack of reliable epidemiological data on the geographical distribution of T. solium teniasis and cysticercosis in humans and pigs.

Establishing adequate surveillance mechanisms could ensure that new cases of cysticercosis in humans and pigs can be reported, which would allow identifying local communities with a high level of risk and taking control and preventive measures in the identified areas measures.