The term encephalitis refers to brain inflammation that can be triggered either by a viral infection or allergy. Infection occurs when the virus enters our body and inhibits the proper functioning of neuron cells, which destroys the immune responses of the body.
The herpes simplex viruses and West Nile virus are the most common viruses that lead to the occurrence of encephalitis. If not treated in a timely manner, encephalitis can have fatal consequences.
How Many Types of Encephalitis Are There?
There are several encephalitis types that are classified according to what causes them, which part of the body is affected, the severity of symptoms, or the part of the world where they occur due to the spread of a viral infection.
However, there are two basic types of inflammation in the brain:
- Primary encephalitis
- Secondary encephalitis
Primary Encephalitis
When the brain is directly affected by a virus located in one of its structures or spread wider in the cerebral cortex, the inflammation is referred to as primary encephalitis.
What Are the Main Causes of Primary Encephalitis?
The main causes of primary encephalitis are:
- The herpes simplex viruses (viruses that are the most common triggers for all types of encephalitis and result in cold sores and genital herpes);
- The varicella zoster virus (resulting in shingles and chickenpox);
- Viruses related to measles, rubella, and mumps;
- Animal-related viruses, such as Japanese encephalitis, Zika virus, rabies, tick-borne encephalitis, etc.
Secondary Encephalitis
When the infection that affects the brain starts somewhere in the body and later spreads to the brain, we refer to the brain inflammation as secondary encephalitis.
Since secondary encephalitis occurs after an initial infection in the body, it’s also labeled as a post-infectious disease of the brain.
What Are the Causes That Trigger the Occurrence of Encephalitis?
The main cause of secondary encephalitis is the immune system failing to respond to a viral threat and prevent it from spreading to the cortical structures. However, it can occur due to a multitude of causes.
By nature, the triggers are classified as:
- Viral,
- Bacterial,
- Fungal,
- Protozoal,
- Helminthic.
Viral Infections
Viruses are not living organisms. They invade the cells and replicate inside. Since they cannot produce energy by themselves, they use the cell’s energy, which weakens the immune defense of the body and leads to illness.
Some viruses, which are enclosed in protein membranes, can be destroyed by ordinary soap. This is why washing hands is the number one rule for keeping viruses at bay.
Viral infections are highly contagious. When the harmful virus enters the body, it destroys the immune system by commandeering the neuron cell’s body. The virus fills the cell with its genetic material and completely changes the functioning of the neuron.
Which Are the Types of Viruses That Can Lead to Encephalitis?
The most common causes of encephalitis are viral infections. They can be triggered by the following types of viruses:
- Common viruses
- Arboviruses
- Childhood viruses
Common Viruses
Common viruses include flu, measles, hepatitis A and B, human papillomavirus, etc.
Arboviruses
Arboviruses are a group of viruses spread by insects, such as mosquitos and ticks. The different types of arboviruses are distinguished according to the type of insect that transmits the virus:
- Eastern equine encephalitis,
- West Nile virus,
- St. Louis encephalitis,
- California encephalitis,
- Kyasanur forest disease.
Childhood Viruses
This group of viruses includes the common cold, flu, respiratory syncytial virus, bronchiolitis, tonsillitis, ear infection, mumps, chickenpox, etc. Vaccines are typically used to prevent childhood virus infection as well as damage to the structures of both the body and brain.
What Are the Symptoms of a Viral Infection?
The symptoms of viral infections include:
- Headache;
- Cough with thick mucus production;
- Nausea and vomiting;
- Fever;
- High temperature;
- Sensitivity to light;
- Fatigue;
- Chills;
- Body aches;
- Dysfunction of some organs;
- Runny nose;
- Diarrhea.
Which Infections or Diseases Are Triggered by Viruses?
The aforementioned symptoms can be a part of the following viral infections:
- Measles,
- Common flu (influenza),
- Chickenpox,
- Polio,
- Norovirus,
- Human papillomavirus (HPV),
- Herpes simplex virus (HSV),
- Human immunodeficiency virus (HIV),
- Viral hepatitis (Type A, b, C, D, or E),
- Rabies,
- Ebola,
- West Nile virus.
Bacterial Infections
Bacteria are microscopic living agents that are visible only under a microscope. They are capable of surviving in severe conditions, which enables them to live both inside and outside other organisms. Namely, bacteria exist in soil, water, air, snow, on almost all known surfaces and materials, in some plants, animals, and even in humans.
Bacterial infections occur after the transmission of bacteria via touch, inhalation, consumption of spoiled food, drinking contaminated water, dirty hands, or polluted surfaces. When bacteria spread in the blood-supplying systems of the brain and body, it can cause sepsis (bacterial infection of the blood).
What are the 4 types of bacteria?
According to their shape, we can distinguish the following types of bacteria:
- Spherical (cocci) bacteria,
- Corkscrew (spirochaetes) bacteria,
- Spiral (spirilla) bacteria,
- Rod (bacilli) bacteria,
- Comma (vibrios) bacteria.
What Are the Symptoms of a Bacterial Infection?
The symptoms of bacterial infections include:
- Ear infection,
- Lung infection,
- Diarrhea,
- Vomiting,
- Upset stomach,
- Throat infection,
- Fever,
- Chills,
- Itching of the skin,
- Urinary tract infections.
Which Infections or Diseases Are Triggered by Bacteria?
The aforementioned symptoms can be a part of the following bacterial infections and diseases:
- Food poisoning (salmonella),
- Escherichia coli,
- Pneumonia,
- Meningitis,
- Pseudomonas aeruginosa,
- Mycobacterium tuberculosis,
- Staphylococcus aureus,
- Cholera,
- Leprosy,
- Plague,
- Syphilis,
- Tetanus,
- Lyme disease,
- Diphtheria,
- Anthrax.
Fungal Infections
Fungal infections (or mycosis) are a skin disease that occurs due to an imbalance of bacteria. This imbalance gives rise to the fungus that invades the skin or the bodily tissues. Antibiotics, stress, and poor eating habits can give rise to fungal infections in our body.
What Are the Symptoms of a Fungal Infection?
The symptoms of fungal infections include:
- Itching,
- Redness,
- Swelling,
- Rash,
- Cracking, thickening, and peeling of the skin,
- Thickening of the nails,
- Chest pain,
- Coughing,
- Fever,
- Muscle aches.
Which Infections or Diseases Are Triggered by Fungi?
The aforementioned symptoms can be a part of the following fungal infections:
- Candidiasis,
- Valley fever,
- Blastomycosis,
- Poisonings,
- Athlete’s foot,
- Ringworm,
- Coccidioidomycosis,
- Pneumocystis pneumonia.
Protozoal Infections
Protozoa are a group of eukaryotes, made up of a single cell body, that can live freely or as parasites. They usually live in human intestines. The transmission of protozoal infections mostly occurs via dirty hands or after contact with feces that may contaminate the food and water we consume.
Are There Different Types of Protozoal Infections?
There are 4 types of protozoa:
- Amoebas,
- Ciliates,
- Apicomplexa,
- Flagellates.
What Are the Symptoms of Protozoal Infection?
The symptoms of protozoal infections include:
- Watery diarrhea,
- Chronic tiredness,
- Flatulence (gastrointestinal gasses),
- Stomach cramps.
Which Infections or Diseases Are Triggered by Protozoa?
The aforementioned symptoms lead to the following protozoal infections:
- African Sleeping Sickness,
- Malaria,
- Chagas disease,
- Toxoplasmosis.
Helminthic Infections
This type of infection is caused by macroparasites (worms). The helminthic infections are usually transmitted by the eggs of parasites via infected soil, where they’re laid, as well as via contact with feces.
What Are the Types of Helminths?
These worm-like parasites can be subdivided into the following classes:
- Flukes (Trematodes),
- Roundworms (Nematodes),
- Tapeworms (Cestodes).
What Are the Symptoms of a Helminth Infection?
The symptoms of helminthic infections include:
- Wheezing,
- Blood-stained sputum,
- Anorexia,
- Weight-loss,
- Nausea,
- Vomiting,
- Diarrhea,
- Obstruction of the bowel function.
Which Infections or Diseases Are Triggered by Helminthosporia?
The aforementioned symptoms can be a part of the following helminthic infections:
- Soil-transmitted helminthiases,
- Food-borne trematodes,
- Clonorchiasis,
- Trichuris trichiura (whipworm),
- Ancylostoma duodenale.
What Are the Symptoms of Encephalitis?
The symptoms that indicate an inflammation of the brain or the spinal cord may be mild or severe.
The following is a list of symptoms that are considered mild:
- Headache,
- Fatigue,
- Low mobility of the neck,
- Vomiting,
- Fever.
The more severe symptoms that alert to an occurrence of encephalitis include:
- High fever,
- Confusion,
- Seizures,
- Coma,
- Sensitivity to light,
- Severe fatigue,
- Hallucinations.
What Complications Can Occur as a Result of Encephalitis?
Primary and secondary encephalitis can lead to a wide range of severe complications that include:
- Inability to coordinate muscle contractions and activity;
- Eyesight problems;
- Fatigue;
- Changes in both personality and behavior;
- Epileptic attacks;
- Impaired cognitive abilities;
- Difficulty breathing;
- Physical weakness;
- Paralysis;
- Problems with the hearing;
- Difficulty speaking and communicating;
- Loss of memory;
- Impaired cognitive abilities of the affected individual;
- Coma;
- Death.
What Are the Disorders Related to Encephalitis?
There are also several disorders related to primary and secondary encephalitis that exhibit similar symptoms and a similar clinical picture of the affected individual:
Herpes Simplex Encephalitis
Herpes simplex encephalitis is an acute viral disease that results in the complication of primary encephalitis caused by the herpes simplex virus. The affected individuals may experience hallucinations, loss of consciousness, hemiparesis (paralysis of the extremities on one side of the body), inflammation of the retina of the eyes, etc.
This disease is highly contagious and can be transmitted from one person to another, while encephalitis does not spread like this.
Meningitis
Meningitis is an inflammatory disease that affects the membranes (meninges) of the brain and the spinal cord. When the bacteria reach the bloodstream of the brain, the cortical structures contract the infection. By large, these types of bacteria are transmitted by direct contact among people, though kissing, sneezing, coughing, etc.
Which Bacteria Cause Meningitis?
Bacteria that trigger the inflammation of the brain membranes include the following types:
- Pneumococcus (Streptococcus pneumoniae),
- Meningococcus (Neisseria meningitidis),
- Escherichia coli.
If not treated in a timely manner, the bacteria-induced inflammation of the brain’s meninges can lead to paralysis, seizures, stroke, or even fatal outcomes.
Neurosyphilis
The infection of the central nervous system in an individual suffering from syphilis is referred to as neurosyphilis. The symptoms of this infectious disease include:
- Loss of ability to walk,
- Numbness of the extremities,
- Cognitive problems,
- Headache,
- Depression,
- Stiffness of the neck.
What Are the Types of Neurosyphilis?
There are 4 types of neurosyphilis:
- General paresis,
- Meningovascular neurosyphilis,
- Tabes dorsalis,
- Asymptomatic neurosyphilis.
How Can We Prevent Primary and Secondary Encephalitis?
Taking good precaution measures is the most efficient way of preventing inflammation of the brain. These measures include:
- Maintaining good personal hygiene,
- Not sharing utensils,
- Not sharing towels,
- Use of insecticides against mosquitoes,
- Drinking safe water,
- Eating properly cleaned and thermally-cooked food,
- Refraining from contact with persons who display symptoms of any viral disease, even the common cold,
- Getting vaccinated.
What Is the Human Immune System and How Does It Function?
The immune system is a defense mechanism of the human body that prevents attacks by various types of viruses, bacteria, fungi, parasites, and toxins. It prevents any damage or complications to the body made by harmful infections and memorizes the ‘attackers’ so that it can act against them in the future.
How Is the Human Immune System Divided?
The human immune system is divided into 2 parts:
- The Acquired Immune System;
- The Innate Immune System.
Despite their mutual role in the protection of the body and brain structures, these two parts of the human immune system differ immensely.
The Acquired Immune System
The acquired immune system refers to the immunological defense systems of the body that are activated after the development of antibodies. This occurs after vaccination or exposure to an infectious disease.
The Innate Immune System
The innate immune system has no need for activation. Namely, this protective mechanism against viruses, bacteria, fungi, or toxins, always actively protects the structures of both body and brain, without any special priming.
Which Parts of the Body Play the Most Important Role in the Human Immune System?
The parts of the body involved in the human immune system include the following structures:
- Lymph nodes,
- Thymus,
- Spleen,
- The lymphatics.
In Which Way Do Vaccines Protect Our Health Against Viral Infections and Diseases?
Vaccines are laboratory-made biological products that support our immune system defenses against infections. They boost the immunity of our body in order to create stronger defense mechanisms against a particular virus or group of viruses.
Each vaccine shot contains a small dose of the dead or weakened virus or bacteria. As such, the vaccine does not infect the organism but rather triggers a response of the immune defenses. Namely, the body recognizes the virus or bacteria, mobilizes its defenses to destroy it, and learns how to recognize it and defend against it in the future.
So far, some of the deadliest viruses and bacteria have been eradicated with the help of global immunization. Immunization provides a healthier and longer life for people, protecting them from the severe effects of viruses which often may have a fatal outcome.
Fun Facts
Did you know?
- It’s unusual for a patient who has recovered from secondary encephalitis to be affected by it again.
- There are around 1031 (10 nonillion) viruses that have been discovered so far on our planet.
- The Coronavirus, or COVID-19, is a virus wrapped in a protein membrane that can be dissolved by soap. Since this destroys the entire virus particle, washing hands with soap is the primary measure recommended in the safety protocols aimed for protection against this widespread virus.
- Various types of animals and plants have and spread their own viruses, such as bats, wild animals, birds, etc. These viruses sometimes evolve into human coronaviruses that can spread very fast and make a large number of people extremely ill.
- Coronaviruses belong to a large virus family that causes respiratory diseases. The common human coronaviruses include HKU1 (beta coronavirus), OC43 (beta coronavirus), NL63 (alpha coronavirus), 229E (alpha coronavirus).
- The types of coronaviruses that have caused the most virulent epidemics/pandemics in the 21st century are MERS-CoV (MERS), SARS-CoV (SARS), and SARS-CoV-2 (COVID-19). All of these coronaviruses trigger severe respiratory problems, with symptoms ranging from headache, dry cough, fever and fatigue, shortness of breath, loss of smell or taste, pain in the chest, inability to move or speak, body aches, etc.
- The SARS coronavirus also causes inflammation of the central nervous system, thus triggering the occurrence of encephalitis.
- Vaccination is the best prevention against viruses and virus-triggered diseases.
- “Germs” is the commonly recognized and popular name for bacteria.
- Tuberculosis is one of the deadliest bacterial diseases in the world! It’s triggered by the Mycobacterium tuberculosis bacteria.