Vaccines can be used to treat an active viral infection.
The progression of the disease from the time of the bite to the time it enters the central nervous system can be two weeks or longer.
This is enough time to give a vaccine to someone who suspects they have been bitten by a bat, and it will give the vaccine time to work.
The fatal neurological consequences of the disease are averted and the individual only has to recover from the bite.
This approach is being used for the treatment of the fastest and most deadly viruses affecting humans, including the one that causes the death of thousands of people every year.
It is a leading cause of death in gorillas.
70-90 percent of the infections can cause death within two weeks, if they are transmitted by bats and great apes.
Using newly developed vaccines that boost the immune response, there is hope that immune systems of affected individuals will be better able to control the virus, potentially reducing mortality rates.
Antiviral drugs are used to treat viral infections.
The drugs have been used to control and reduce symptoms of a wide variety of viral diseases.
These drugs block the actions of one or more of the virus's genes.
It is important that the targets are not present in a healthy cell.
In this way, there is no harm to the host.
There are many different types of drugs that can be used to treat infections.
Antivirals can be used to treat genital herpes.
The number and duration of episodes of active viral disease can be reduced with the use of drugs such as acyclovir.
This drug is not a cure but can make the symptoms of the disease more manageable.
The duration of "flu" symptoms can be reduced by one or two days, but the drug does not prevent symptoms entirely.
Ribavirin has been used to treat a variety of viral infections.
The most successful use of antivirals has been in the treatment of the retroviruses HIV, which causes a disease that is usually fatal within a decade after being exposed.
Anti-HIV drugs have been able to control the replication of the disease, which means that people who receive these drugs live longer than those who don't.
The fusion of the HIV viral envelope with the host cell is one of the drugs that have been developed.
The virus can rapidly evolve resistance to the drug when any of these drugs are used alone.
It is difficult for the virus to develop resistance to multiple drugs at the same time if it is attacked at different stages of its replication cycle.
Even with the use of combination HAART therapy, there is concern that the virus will evolve resistance over time.
New anti-HIV drugs are being developed with the hope of continuing the battle against the deadly virus.
The immune system is a complex system that protects the integrity of the body.
The second line of defense of the innate system includes chemical signals that cause inflammation and fever responses as well as mobilizing protective cells and other chemical defenses.
The immune system mounts a response to substances that are not in the body.
The adaptive system takes longer to respond and has a memory system that will allow it to respond with greater intensity if the body begins to fight a pathogen again.
The immune system is made up of two main parts.
The innate immune system is made up of physical barriers and internal defenses.
The immune system is very specific.
There are physical barriers to potential pathogens in the body.
The skin contains a substance that resists entry into cells.
Body openings and other body surfaces are protected by the mucous membranes.
The mucus is sticky and prevents the movement of pathogens into the body.
The nose and ears are protected by hairs that catch diseases, and the upper respiratory tract has cilia that move diseases from the mucus coat to the mouth.
A hostile chemical environment is created by the skin and mucous membranes.
The surface of the skin is acidic.
The tears of the eye contain anidase that breaks down the cell walls.
The acidic environment of the stomach causes many diseases to enter the system.
There is a community of organisms on the surface of the body and the lower digestive system that do not harm the body.
There is evidence that these organisms are beneficial to their host, fighting disease-causing organisms and outcompeting them for nutrition.
Infections can enter the body through punctures or skin abrasions, or by collecting on mucosal surfaces in large numbers that overcome the protections of mucus or cilia.
The innate immune system responds to pathogens with a variety of internal defenses.
The inflammatory response, natural killer cells, and complement system are included.
White blood cells can leave the blood to go to infections.
They are responsible for releasing chemicals when injured.
They play a role in the allergic response, which will be discussed later in the chapter.
Chemicals called cytokines are released when a pathogen is recognized as foreign.
Humans have around 40 different types of cytokines.
In addition to being released from white blood cells after pathogen recognition, cytokines are also released by theinfecting cells and bind to nearby uninfecting cells, inducing those cells to release cytokines.
One class of early-acting cytokines is the interferons, which are released byinfecting cells as a warning to nearby uninfecting cells.
There are compounds that interfere with viral replication that are stimulated by the interferons.
Interferons are activated by other cells.
Inflammation is a response to physical trauma, such as a cut or a blow.
The chemical signals that cause an inflammatory response enter the fluid and cause the capillary walls to dilate.
The Immune System and Disease capillaries cause swelling of the area, which in turn causes pain.
White blood cells are attracted to inflammation.
The type of white blood cells that arrive at an inflammation depends on the injury or pathogen.
Macrophages are involved in the resolution of an inflammatory site, cleaning up cell debris and pathogens.
The inflammatory response is stimulated by the release of chemicals from white blood cells.
The overall symptoms of feeling sick include nausea, muscle pain, and lethargy.
The core body temperature increases with the help of cytokines.
The growth of pathogens is slowed by the elevated temperatures of a fever.
suppression should be limited to those that are dangerously high.
During an elapsed time of 78 minutes, you can see this neutrophil that searches and kills fungus.
All nucleated cells have MHC class I molecule on their surfaces that give a sample of the cell's internal environment at any given time.
Unhealthy cells have altered MHC class I complement on their cell surfaces.