Causes of Viral diseases
List of causes of Viral diseases
Following is a list of causes or underlying conditions
(see also Misdiagnosis of underlying causes of Viral diseases)
that could possibly cause Viral diseases includes:
Viral diseases Causes: Book Excerpts
Viral diseases as a symptom:
Conditions listing Viral diseases
as a symptom may also be potential underlying causes of Viral diseases.
Our database lists the following as having
Viral diseases as a symptom of that condition:
Medications or substances causing Viral diseases:
The following drugs, medications, substances or toxins are some of the possible
causes of Viral diseases as a symptom.
This list is incomplete and various other drugs or substances
may cause your symptoms.
Always advise your doctor of any medications or treatments you are using,
including prescription, over-the-counter, supplements, herbal or alternative treatments.
See full list of 23
medications causing Viral diseases
What causes Viral diseases?
Causes: Viral diseases:
Viruses are infectious microbes that can be inside or outside cells.
They are little strips of DNA (or RNA) usually wrapped inside a tiny capsule.
Viruses are not even a single cell,
but are a tiny part of a cell, and thus they are much smaller even than bacteria.
Viruses are not alive in the normal sense.
They do not feed, nor do they generate energy or waste products.
Viruses are effectively inert until they attach to a live body cell.
But once they attach, they become alive in a sense.
They enter the cell, breaking open the capsule,
so that their inside contents of DNA or RNA strips enter the cell.
Because this viral DNA looks like normal DNA,
the cell starts to copy it like the cell does to ordinary DNA.
In this way, the body cell is tricked into making many copies of the virus inside the cell.
Eventually, the cell is killed and these newly created viruses are expelled into
the body to infect more cells.
Unlike most bacteria, most viruses do cause disease because they invade
living, normal cells, such as those in the human body. They then multiply
and produce other viruses like themselves. Each virus is very particular
about which cell it attacks. Various human viruses specifically attack
particular cells in the body's organs, systems, or
tissues, such as the liver, respiratory system, or blood
cells. (Source: excerpt from Microbes in Sickness and in Health - Publications, National Institute of Allergy and Infectious Diseases: NIAID)
Medical news summaries relating to Viral diseases:
The following medical news items are relevant to causes of Viral diseases:
Related information on causes of Viral diseases:
As with all medical conditions,
there may be many causal factors.
Further relevant information on causes of Viral diseases may be found in:
Causes of Viral diseases: Online Medical Books
16 MEDICAL BOOKS ONLINE!
Review excerpts from medical books online, free, without registration,
for more information about the causes of Viral diseases.
Respiratory syncytial virus infection:
Causes and incidence
(Professional Guide to Diseases (Eighth Edition))
The organism that causes RSV is transmitted from person to person by respiratory secretions and has an incubation period of 4 to 5 days. Antibody titers seem to indicate that few children younger than age 4 escape contracting some form of RSV, even if it's mild. In fact, RSV is the only viral disease that has its maximum impact during the first few months of life (incidence of RSV bronchiolitis peaks at age 2 months). School-age children, adolescents, and young adults with mild reinfections are probably the source of infection for infants and young children.
This virus occurs in annual epidemics during the late winter and early spring in temperate climates and during the rainy season in the tropics. It can also be seen in immunocompromised adults, especially patients with bone marrow transplants.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Ebola virus infection:
Causes
(Professional Guide to Diseases (Eighth Edition))
Ebola virus infection is caused by an unclassified RNA virus that’s passed from person to person by direct contact with infected blood, body secretions, or organs. Nosocomial and community-acquired transmission can occur. Contaminated needles can also cause the infection. Transmission through semen may occur up to 7 weeks after clinical recovery. The virus remains contagious even after the patient has died.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Viral hepatitis:
Causes and incidence
(Professional Guide to Diseases (Eighth Edition))
The major forms of viral hepatitis result from infection with the causative viruses: A, B, C, D, E, or G.
Type A hepatitis is highly contagious and is usually transmitted by the fecal-oral route. However, it may also be transmitted parenterally. Hepatitis A usually results from ingestion of contaminated food, milk, or water. Many outbreaks of this type are traced to ingestion of seafood from polluted water. In 2001, there were more than 10,000 acute cases of hepatitis A infection reported in the United States.
Type B hepatitis, once thought to be transmitted only by the direct exchange of contaminated blood, is now known to be transmitted also by contact with human secretions and feces. As a result, nurses, physicians, laboratory technicians, and dentists are frequently exposed to type B hepatitis, in many cases as a result of wearing defective gloves. Transmission also occurs during intimate sexual contact as well as through perinatal transmission. An estimated 200,000 new cases of hepatitis B virus (HBV) and 5,000 deaths from HBV occur annually in the United States.
Although specific type C hepatitis viruses have been isolated, only a small percentage of patients have tested positive for them — perhaps reflecting the test’s poor specificity. Usually, this type of hepatitis is transmitted through transfused blood from asymptomatic donors. Hepatitis C accounts for 30,000 new infections and 8,000 to 10,000 deaths each year in the United States. Most exposures (60%) occur through the use of illicit I.V. drugs. However, sexual transmission is responsible for 20% of cases. More than 170 million people have the hepatitis C virus worldwide.
Type D hepatitis is found only in patients with an acute or chronic episode of hepatitis B and requires the presence of HBsAg. The type D virus depends on the double-shelled type B virus to replicate. For this reason, type D infection can’t outlast a type B infection. About 15 million people are infected with hepatitis D worldwide. It’s more common in adults than in children. People with a history of illicit I.V. drug use and people who live in the Mediterranean basin have a higher incidence.
Type E hepatitis is transmitted enterically, much like type A. Because this virus is inconsistently shed in feces, detection is difficult. In the United States, the prevalence of hepatitis E is less than 2%. It’s typically found in developing countries that lie near the equator. Incidence is highest among people ages 15 to 40.
Type G may be transmitted in a manner similar to that of hepatitis C. It may also be transmitted by sexual contact, and its incidence may be higher than previously suspected. It’s associated with acute and chronic liver disease, but studies haven’t clearly implicated the hepatitis G virus as an etiologic agent.
Other proposed causative factors, such as non-ABCDE viral hepatitis and type F, are under investigation.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Respiratory syncytial virus infection:
Causes
(Handbook of Diseases)
Antibody titers seem to indicate that few children younger than age 4 escape contracting some form of RSV, even if it’s mild. In fact, RSV is the only viral disease that has its maximum impact during the first few months of life (incidence of RSV bronchiolitis peaks at age 2 months).
This virus creates annual epidemics that occur during late winter and early spring in temperate climates and during the rainy season in the tropics. The organism is transmitted from person to person by respiratory secretions and has an incubation period of 4 to 5 days. Those at higher risk include infants who are exposed to tobacco smoke, attend day-care centers, live in crowded conditions, or have school-age siblings.
Reinfection is common, producing milder symptoms than the primary infection. School-age children, adolescents, and young adults with mild re-infections are probably the source of infection for infants and young children.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Diseases, 2003
Ebola virus infection:
Causes
(Handbook of Diseases)
Ebola virus disease is caused by an unclassified RNA virus that’s transmitted by direct contact with infected blood, body secretions, or organs. Nosocomial and community-acquired transmission can occur. The virus remains contagious even after the patient has died.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Diseases, 2003
Human immunodeficiency virus infection:
Causes
(Handbook of Diseases)
The virus has two major strains: HIV-1, which is closely related to the primate retrovirus called simian immunodeficiency virus, and HIV-2, which is associated with immunodeficiency but less pathogenic that HIV-1, results from infection with HIV, which strikes cells bearing the CD4+ antigen; the latter (normally a receptor for major histocompatibility complex molecules) serves as a receptor for the retrovirus and lets it enter the cell. HIV prefers to infect the CD4+ lymphocyte or macrophage but may also infect other CD4+ antigen-bearing cells of the GI tract, uterine cervical cells, and neuroglial cells. The virus gains access by binding to the CD4+ molecule on the cell surface along with a co-receptor (thought to be the receptor CCR5). After invading a cell, HIV either replicates, which leads to cell death, or becomes latent. HIV infection leads to profound pathology, either directly, through destruction of CD4+ T cells, other immune cells, and neuroglial cells, or indirectly, through the secondary effects of CD4+ T-cell dysfunction and resultant immunosuppression.
The infection process takes three forms:
❑ immunodeficiency (opportunistic infections and unusual cancers)
❑ autoimmunity (lymphoid interstitial pneumonia, arthritis, hypergammaglobulinemia, and production of autoimmune antibodies)
❑ neurologic dysfunction (AIDS dementia complex, HIV encephalopathy, and peripheral neuropathies).
Transmission
HIV is transmitted by direct inoculation during intimate sexual contact, especially associated with the mucosal trauma of receptive rectal intercourse; transfusion of contaminated blood or blood products (a risk diminished by routine testing of all blood products); sharing of contaminated needles; or transplacental or postpartum transmission from an infected mother to the fetus (by cervical or blood contact at delivery and in breast milk).
HIV isn’t transmitted by casual household or social contact. The average time between exposure to the virus and diagnosis is 8 to 10 years, but shorter and longer incubation times have also been recorded. Most people develop antibodies within 6 to 8 weeks of contracting the virus.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Diseases, 2003
Hepatitis, viral:
Causes
(Handbook of Diseases)
The major forms of viral hepatitis result from infection with the causative viruses: A, B, C, D, E, or G.
Type A hepatitis
Hepatitis A is highly contagious and usually transmitted by the fecal-oral route. It may also be transmitted parenterally.
Clinical tip I.V. drug abusers and recipients of multiple blood product transfusions are at increased risk for hepatitis A.
Hepatitis A usually results from ingestion of contaminated food, milk, or water. Outbreaks of this type are commonly traced to ingestion of seafood from polluted water.
Type B hepatitis
Once thought to be transmitted only by the direct exchange of contaminated blood, hepatitis B is now also known to be transmitted by contact with human secretions and stool passed by health care workers, recipients of plasma-derived products, and hemodialysis patients. As a result, nurses, physicians, laboratory technicians, and dentists are frequently exposed to type B hepatitis, commonly as a result of wearing defective gloves.
Transmission also occurs during intimate sexual contact and through perinatal transmission.
Type C hepatitis
Although hepatitis C viruses have been isolated, only a small percentage of patients have tested positive for them, perhaps reflecting the test’s poor specificity. Usually, this type of hepatitis is transmitted through transfused blood from asymptomatic donors and receiving tattoos.
Clinical tip Most patients with hepatitis C are asymptomatic. Hepatitis C virus is associated with a high rate of chronic liver disease (chronic hepatitis, cirrhosis, and an increased risk of hepatocellular carcinoma), which develops in 50% to 80% of those infected. People who have chronic hepatitis C are considered infectious.
Type D hepatitis
Hepatitis D is found only in patients with an acute or a chronic episode of hepatitis B and requires the presence of HBsAg. The type D virus depends on the double-shelled type B virus to replicate. For this reason, a type D infection can’t outlast a type B infection.
Hepatitis D is rare in the United States, except in I.V. drug abusers.
Type E hepatitis
Hepatitis E is transmitted enterically (oral-fecal and waterborne routes), much like type A. Because this virus is inconsistently shed in feces, detection is difficult.
Type G hepatitis
Hepatitis G, a newly identified virus, is transmitted by the blood-borne route, similar to hepatitis C.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Diseases, 2003
Most of us are familiar with the symptoms of the flu—fever, chills, fatigue, stuffy nose, sore throat. Most of us know that it is caused by the...
Each year you hear about small outbreaks of meningitis. It is highly contagious and sometimes fatal. Learn why the classic symptoms of a high fever...
Adults may already know the new ways to avoid catching and spreading the flu. But you may need to teach these behaviors to kids. Listen to an...
Genital herpes remains one of the most prevalent sexually transmitted diseases, but most don't know they are infected. Learn how to stay safe and...
See full list of 12 related videos
» Next page:
Risk Factors for Viral diseases
Rate This Website
What do you think about the features of this website?
Take our user survey and have your say:
Website User Survey
Medical Tools & Articles:
Next articles:
Tools & Services:
Medical Articles:
Forums & Message Boards
- Ask or answer a question at the Boards:
