Hepatitis - jaundice

Description
Hepatitis disease commonly known as jaundice. Actually hepatitis is liver inflammation (liver) caused by various factors. Factors that cause hepatitis or jaundice, among others, is a viral infection, metabolic disorders, alcohol consumption, autoimmune diseases, results complications from other diseases, side effects from the consumption of drugs and the presence of parasites in the liver,

Symptoms
One of the symptoms of hepatitis is the emergence of yellow color on the skin, nails and the whites of the eyeball.

Therapy
Usual medical therapy medical therapy is usually given to patients with hepatitis among other diseases, bed rest, healthy diet, and administration of drugs and antiviral.

Anthrax

Description
Anthrax is a bacterial disease caused by Bacillus anthracis, which lives in soil. Such as bacterial spores to survive the fierce conditions. Spores thrive in a colony in the animal or human body.

Anthrax sometimes attack livestock away from the man, but - as known in the 2001 anthrax attack the United States - fear anthrax as a weapon of modern biology. Atraks transmission through meat or skin anthrax-affected animals eaten by humans.

Symptoms
The average incubation period of anthrax is more than 7 days, 60 days can be even more depending on the duration of symptoms is formed. Patients usually have symptoms of anthrax, among others, swollen, fever, anxiety, headaches, and generally feel uneasy.

Medical
If diagnosed early, anthrax easily treated with atibiotik. But sometimes, people ignore the early symptoms of anthrax before they actually had symptoms become more severe. Antibiotics for anthrax can kill bacteria, but antibiotics have no effect on anthrax toxin.

HOW TO PREVENT AIDS ??

HOW TO PREVENT AIDS ??

The three main transmission routes of HIV are sexual contact, exposure to infected body fluids or tissues, and from mother to fetus or child during perinatal period. It is possible to find HIV in the saliva, tears, and urine of infected individuals, but there are no recorded cases of infection by these secretions, and the risk of infection is negligible.

1. SAFE SEX (use condom)
During a sexual act, only male or female condoms can reduce the chances of infection with HIV and other STDs and the chances of becoming pregnant. The best evidence to date indicates that typical condom use reduces the risk of heterosexual HIV transmission by approximately 80% over the long-term, though the benefit is likely to be higher if condoms are used correctly on every occasion.

2. Exposure to infected body fluids
Health care workers can reduce exposure to HIV by employing precautions to reduce the risk of exposure to contaminated blood. These precautions include barriers such as gloves, masks, protective eyeware or shields, and gowns or aprons which prevent exposure of the skin or mucous membranes to blood borne pathogens. Frequent and thorough washing of the skin immediately after being contaminated with blood or other bodily fluids can reduce the chance of infection. Finally, sharp objects like needles, scalpels and glass, are carefully disposed of to prevent needlestick injuries with contaminated items. Since intravenous drug use is an important factor in HIV transmission in developed countries, harm reduction strategies such as needle-exchange programmes are used in attempts to reduce the infections caused by drug abuse.

3. Mother-to-child transmission (MTCT)
Current recommendations state that when replacement feeding is acceptable, feasible, affordable, sustainable and safe, HIV-infected mothers should avoid breast-feeding their infant. However, if this is not the case, exclusive breast-feeding is recommended during the first months of life and discontinued as soon as possible.

What is HIV ?

What is HIV ?
Human immunodeficiency virus (HIV) is a lentivirus (a member of the retrovirus family) that can lead to acquired immunodeficiency syndrome (AIDS), a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections. Previous names for the virus include human T-lymphotropic virus-III (HTLV-III), lymphadenopathy-associated virus (LAV), and AIDS-associated retrovirus (ARV).

How HIV Infect People ?
Infection with HIV occurs by the transfer of blood, semen, vaginal fluid, pre-ejaculate, or breast milk. Within these bodily fluids, HIV is present as both free virus particles and virus within infected immune cells. The four major routes of transmission are unprotected sexual intercourse, contaminated needles, breast milk, and transmission from an infected mother to her baby at birth (Vertical transmission). Screening of blood products for HIV has largely eliminated transmission through blood transfusions or infected blood products in the developed world.

In general if infected blood comes into contact with any open wound, HIV may be transmitted. This transmission route can account for infections in intravenous drug users, hemophiliacs and recipients of blood transfusions (though most transfusions are checked for HIV in the developed world) and blood products. It is also of concern for persons receiving medical care in regions where there is prevalent substandard hygiene in the use of injection equipment, such as the reuse of needles in Third World countries. Health care workers such as nurses, laboratory workers, and doctors have also been infected, although this occurs more rarely. People who give and receive tattoos, piercings, and scarification procedures can also be at risk of infection.

Since transmission of HIV by blood became known medical personnel are required to protect themselves from contact with blood by the use of Universal precautions.

Virus Transmission
* Mother to Child Transmission
The transmission of the virus from the mother to the child can occur in utero during pregnancy and intrapartum at childbirth. In the absence of treatment, the transmission rate between the mother and child is around 25 percent. However, where combination antiretroviral drug treatment and Cesarian section are available, this risk can be reduced to as low as one percent.
Breast feeding also presents a risk of infection for the baby.

* From Saliva, Tears & Urine
HIV has been found at low concentrations in the saliva, tears and urine of infected individuals, but there are no recorded cases of infection by these secretions and the potential risk of transmission is negligible.

HIV Treatment
There is currently no vaccine or cure for HIV or AIDS. The only known method of prevention is avoiding exposure to the virus. However, a course of antiretroviral treatment administered immediately after exposure, referred to as post-exposure prophylaxis, is believed to reduce the risk of infection if begun as quickly as possible. Current treatment for HIV infection consists of highly active antiretroviral therapy, or HAART. This has been highly beneficial to many HIV-infected individuals since its introduction in 1996, when the protease inhibitor-based HAART initially became available. Current HAART options are combinations (or "cocktails") consisting of at least three drugs belonging to at least two types, or "classes," of antiretroviral agents. Typically, these classes are two nucleoside analogue reverse transcriptase inhibitors (NARTIs or NRTIs) plus either a protease inhibitor or a non-nucleoside reverse transcriptase inhibitor (NNRTI). New classes of drugs such as Entry Inhibitors provide treatment options for patients who are infected with viruses already resistant to common therapies, although they are not widely available and not typically accessible in resource-limited settings. Because AIDS progression in children is more rapid and less predictable than in adults, particularly in young infants, more aggressive treatment is recommended for children than adults. In developed countries where HAART is available, doctors assess their patients thoroughly: measuring the viral load, how fast CD4 declines, and patient readiness. They then decide when to recommend starting treatment.

The Meaning Of AIDS

SYMPTOMS:
The symptoms of AIDS are primarily the result of conditions that do not normally develop in individuals with healthy immune systems. Most of these conditions are infections caused by bacteria, viruses, fungi and parasites that are normally controlled by the elements of the immune system that HIV damages.

Opportunistic infections are common in people with AIDS. HIV affects nearly every organ system.

People with AIDS also have an increased risk of developing various cancers such as Kaposi's sarcoma, cervical cancer and cancers of the immune system known as lymphomas. Additionally, people with AIDS often have systemic symptoms of infection like fevers, sweats (particularly at night), swollen glands, chills, weakness, and weight loss. The specific opportunistic infections that AIDS patients develop depend in part on the prevalence of these infections in the geographic area in which the patient lives.

MAIN CAUSE :

Sexual Relation

The majority of HIV infections are acquired through unprotected sexual relations between partners, one of whom has HIV. The primary mode of HIV infection worldwide is through sexual contact between members of the opposite sex.

During a sexual act, only male or female condoms can reduce the chances of infection with HIV and other STDs and the chances of becoming pregnant. The best evidence to date indicates that typical condom use reduces the risk of heterosexual HIV transmission by approximately 80% over the long-term, though the benefit is likely to be higher if condoms are used correctly on every occasion.

Sexual transmission occurs with the contact between sexual secretions of one person with the rectal, genital or oral mucous membranes of another. Unprotected receptive sexual acts are riskier than unprotected insertive sexual acts, and the risk for transmitting HIV through unprotected anal intercourse is greater than the risk from vaginal intercourse or oral sex.

However, oral sex is not entirely safe, as HIV can be transmitted through both insertive and receptive oral sex. Sexual assault greatly increases the risk of HIV transmission as protection is rarely employed and physical trauma to the vagina frequently occurs, facilitating the transmission of HIV.

Exposure to blood-borne pathogens

This transmission route is particularly relevant to intravenous drug users, hemophiliacs and recipients of blood transfusions and blood products. Sharing and reusing syringes contaminated with HIV-infected blood represents a major risk for infection with HIV.

Needle sharing is the cause of one third of all new HIV-infections in North America, China, and Eastern Europe. The risk of being infected with HIV from a single prick with a needle that has been used on an HIV-infected person is thought to be about 1 in 150. Post-exposure prophylaxis with anti-HIV drugs can further reduce this risk.

Perinatal transmission
The transmission of the virus from the mother to the child can occur in utero during the last weeks of pregnancy and at childbirth. In the absence of treatment, the transmission rate between a mother and her child during pregnancy, labor and delivery is 25%.

Misconceptions
A number of misconceptions have arisen surrounding HIV/AIDS. Three of the most common are that AIDS can spread through casual contact, that sexual intercourse with a virgin will cure AIDS, and that HIV can infect only homosexual men and drug users. Other misconceptions are that any act of anal intercourse between gay men can lead to AIDS infection, and that open discussion of homosexuality and HIV in schools will lead to increased rates of homosexuality and AIDS.

Ayurvedic Management of HIV/AIDS

At present, there is no scientifically proved cure for HIV /AIDS. Globally, the number of infected HIV /AIDS patients is increasing at an alarming rate; with a current estimate of 33.2 million people who are living with HIV 1. Hence, there is a dire need to search for a safe, effective and economical treatment for HIV /AIDS.

In a retrospective study in 55 patients, Ayurvedic treatment has proved to be very promising in the management of HIV/AIDS. Fifty-Five adult patients were given Ayurvedic treatment for HIV/AIDS, during the period from April 1999 to November 2004.Each patient had tested positive for HIV/AIDS on at least 2 different occasions. No patient was taking anti-retroviral drugs at the time of commencing Ayurvedic treatment. All patients were started on treatment after written, informed consent.

The Ayurvedic Herbal Combination ( AHC ) comprises of eleven different herbs in different dosage strengths, based upon their respective potencies, reported anti-viral and immunomodulatory properties, and their traditional usage according to Ayurvedic principles of medicine 2 -4 .The constituents of AHC with their respective dosages are as follows:-Terminalia arjuna: 250 mg. ;Zinziber officinale: 250 mg. ;Phyllanthus niruri :1 gm ;Glycyrrhiza glabra:1gm. ;Withania somnifera:1gm. ;Eclipta alba: 250mg. ;Centella asiatica: 250mg. ;Boerhavia diffusa: 250mg. ;Emblica officinalis: 250mg. ;Tinospora cordifolia: 250mg. ;Rubia cordifolia: 250mg. This AHC was dispensed in a combined dose of 5 gms. t.i.d., to be taken with water after meals. Aqueous herbal extracts of all the medicines were used, in tablet form.

All patients were advised to eat a well-balanced, nutritious diet. Therapeutic counseling sessions were conducted regularly to help the patients achieve mind relaxation, to modify their risk behavior , and to increase adherence and compliance to therapy.

All patients were followed up at monthly intervals. Detailed clinical examination was done at each visit and significant findings were recorded. In addition, in affording and willing patients, investigations like CBC, Hb, Liver and Renal functions, X-Ray of chest, Western Blot, CD4 count and Viral Load were done wherever possible. Other investigations were done, if required, for Opportunistic Infections (O.I.).All O.I. were promptly and aggressively treated with modern medicines. A close watch was kept for adverse reactions of the drugs.

Therapeutic outcome was assessed by overall clinical examination, change in Karnofsky score (assessment for overall well-being of patients), change in weight, occurrence and response to O.I., and change in CD4 and Viral Load values. Maximum number of patients was in the age ranging from 20 - 39 years (80 %). Of the total number of 55 patients, 39 were male (71 % ) and 16 were female (29 %), with the male: female ratio being 2.4: 1. There were 7 couples who took treatment together.

Of the 55 patients, 5 patients died, 42 patients took treatment for varying periods and then stopped treatment, while 8 patients continued treatment till the end of the study period. The 5 patients who died were critically ill at the time of presentation, and died mostly within the first two months of starting Ayurvedic treatment. The cause of death varied ; 1 patient died from cirrhosis of the liver, 3 died of extensive Pulmonary Tuberculosis (multi-drug resistant) and 1 died of a combination of Pulmonary Tuberculosis and demyelination disease of the brain.

In the 50 patients who were alive till the time of their last follow-up , there was an average weight-gain of 2.3 kgs.(range = - 4 to + 7.5 kgs), usually within the first 3 months. In those patients who took continuous treatment for more than 3 months, the Karnofsky score increased from an average of 75.9 at the commencement of treatment to 87.4 at the last follow-up. Almost all the patients had 1-3 O.I. at the time of presentation. Other than Tuberculosis, all the O.I. cleared up rapidly within the first 2 months of treatment.

Long-term administration of Ayurvedic medicines (upto 30 months) did not seem to have any major adverse effects. In fact, in a few patients, the tests for liver and renal function appeared to normalize further, with treatment. Haemoglobin readings gradually improved in those patients taking regular, prolonged treatment.The most striking effect of the Ayurvedic medicines was on the Viral Load and CD4 counts. Because of financial constraints, only 15 patients (27 % ) agreed to do either the Viral Load or the CD4 count, or both. In most patients, there was a definite and steady decrease in the Viral Load, and an increase in the CD4 cell counts.

Antiretroviral medicines are the mainstay in the modern treatment of HIV/AIDS. However, a plethora of side-effects, development of resistance to drugs and escalating treatment costs are serious concerns. In the absence of a definite cure for HIV/AIDS, Ayurvedic medicines may provide a useful alternative for long-term management of patients, since these medicines are economical and devoid of serious side-effects. However, scientific research is necessary to determine efficacy of these medicines. This retrospective study is one such effort to assess long-term therapeutic effects of an Ayurvedic Herbal Combination in the management of HIV /AIDS.

In this study, 4 patients died within the first 2 months of commencing treatment. Onset of therapeutic effect is slow with Ayurvedic medicines, and these patients probably could not benefit from Ayurvedic treatment. This emphasizes the need to start treatment as early as possible in immuno-compromised patients. The causes of death indicate that Tuberculosis and CNS involvement are major killers in HIV patients. Multi-drug resistance to Tuberculosis is also a major concern.

16 patients ( 29% ) did not come back after just one ( 11% ) or two ( 18% ) visits. The reasons cited were, a complete inability to pay for treatment, or a search for a ‘better’ or a ‘guarenteed cure’. Fortunately, perceptions have changed in the last few years. Even illiterate patients from the lower socio-economic strata are no longer asking for a ‘guarantee’ or a ‘cure’. ‘Long-term management with minimum expenses’ is a mantra being readily accepted by the HIV positive patient of today.

All the patients who took medicines regularly, had a high-protein diet and kept themselves busy, improved very well and put on weight. Even 2 to 3 years after stopping Ayurvedic treatment, most of the patients are doing very well, some inspite of very low CD4 counts. This is probably one of the biggest long-term advantages of taking Ayurvedic medicines for HIV /AIDS. However, patients with socio-economic difficulties and a lot of psychological pressure who could not have access to regular treatment, started losing weight after initially improving with treatment. A comprehensive management of each patient thus needs to address several issues relevant to each individual patient.

This study also brought forth some interesting results. One patient who subsequently died, had severe demyelinating disease of the brain (as diagnosed in a major hospital), and had lost most of his motor control and sensory senses, since several months. After being given Ayurvedic treatment for about 1 ½ months he became alert, and could speak clearly, albeit temporarily, for 1 week. Another patient with Nephrotic syndrome resulting in long-standing generalized oedema (2 years ) had complete regression of the oedema after 2 months of Ayurvedic treatment without any other treatment. One HIV positive patient with suspected malignancy of lung in the right upper lobe was steadily losing weight. After starting Ayurvedic treatment, he started putting on weight. Another patient with history suggestive of HIV Encephalopathy was semi-conscious at presentation. He was passively fed on liquid diet and a combination of both modern drugs and Ayurvedic treatment. This patient be!

came ambulatory within 2 weeks, and after 2 months of treatment he was faring well, even with a CD4 count of just 6.The above 4 instances indicate that the Ayurvedic medicines may have multi-faceted properties and need further evaluation.

Thus,the retrospective study of 55 HIV positive adult patients treated with an Ayurvedic Herbal combination from April 1999 to November 2004 proved the Ayurvedic medicines to be highly effective as anti-viral and immuno-stimulant,and safe on long-term use. A nutritious diet, Ayurvedic baseline therapy, timely allopathic treatment of Opportunistic Infections and regular counseling support appears to be an ideal combination in the management of HIV/ AIDS patients.

The Changing Face of AIDS

AIDS first came to the medical scene and public attention in the 1970’s; then a diagnosis of AIDS was a death sentence. The life expectancy of anyone who had contracted the disease was very short making a study of the long term effects of the disease difficult.

The rapidly mutating virus developed resistance to the drugs that were used to suppress it. In the mid 1990’s drug “cocktails,” multi drug combinations of antiretroviral drugs were able to provide barriers to mutation. The number of deaths for AIDS patients dropped dramatically and long term aspects of the disease changed. Victims could expect longer life spans though they would require medication the rest of their lives.

The longer life expectancy of AIDS patients presented another set of problems. AIDS patients are living longer, but they are aging faster. Those in the 50 to 60 age group who suffer from AIDS, have the health issues that most people do not experience until they are a decade older.

The number of AIDS sufferers over the age of 50 has increased by 77% from 2001 to 2005, and now more than a quarter of the approximately one million active AIDS cases in this country are advanced in age. Of 5,049 patients who began AIDS therapy between 1995 and 2004, 997 were over the age of 50, 1,834 were 40-49 and the rest were between 18-39 years of age. AIDS presented new challenges to the medical community in the 70’s and 80’s and now the problems presented in the aging AIDS population is again challenging the medical community.

There is presently no data that specifically compares the onset of geriatric diseases between AIDS and non AIDS patients, but the medical community says that people in their mid-50’s, without AIDS, usually do not have heart disease or diabetes associated with lipodystrophy or oesteoporosis without additional risk factors.

Lipodystrophy is a side effect of the drugs that keeps HIV in check. It rearranges fat in the body and can lead to the sunken eyes and cheeks usually associated with advanced age. It can lead to insulin resistance and raise triglyceride levels. Individuals on AIDS therapy treatment are usually treated with corticosteroids to protect against other opportunistic infections that prey on HIV weakened immune systems. This can lead to a bone disease, vascular necrosis, and the necessity for hip replacement surgery. Other aging problems with HIV are the development of memory deficits and liver and kidney disease.

In a Jan 6, 2008 article in the International Herald Tribune, Jane Gross quotes Dr. Tom Barrett, medical director of Howard Brown, “All we can do right now is to make inferences from thing to thing to thing. They might have gotten some of these diseases anyway. But the rates and the timing, and the association with certain drugs, makes everyone feel that this is a different problem.”

Why is this happening? There haven’t been any studies to provide sound statistics of what problems are related to AIDS. Only recently have there been enough aging AIDS patients to study. The initial assumptions are that those who have survived with the AIDS infection, have immune systems and organs that first took a beating from the disease, and then were further damaged by the toxicity of the antiretroviral drugs which they took to survive the disease.

With lack of research, patient care suffers. Barrett says the incidence of osteoporosis warrants routine screening. However, in the United States, Medicare, Medicaid and most private insurers will not cover bone density tests for middle aged men.

The New York-based AIDS Community Research Initiative of America, in trying to provide help and assistance to older individuals with AIDS, found that depression, which is common to the elderly, is even higher among longtime AIDS survivors. They often grow despondent because of health issues and the deaths of friends and associates.

Mary Engel, writing in the Los Angeles Times on February 5, 2008 quotes Los Angeles resident and long time survivor Thomas Woolsey, 59, “Everybody I knew died in the late ‘80’s or early ‘90’s. It sounds like I’m the lucky one, but I don’t really think so. What good is a life without any friends?”

Flu = Influenza

influenza virus

Influenza, commonly known as flu, is an infectious disease of birds and mammals caused by RNA viruses of the family Orthomyxoviridae (the influenza viruses). In humans, common symptoms of influenza infection are fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort. In more serious cases, influenza causes pneumonia, which can be fatal, particularly in young children and the elderly. Sometimes confused with the common cold, influenza is a much more severe disease and is caused by a different type of virus.Although nausea and vomiting can be produced, especially in children, these symptoms are more characteristic of the unrelated gastroenteritis, which is sometimes called "stomach flu" or "24-hour flu."

Typically, influenza is transmitted from infected mammals through the air by coughs or sneezes, creating aerosols containing the virus, and from infected birds through their droppings. Influenza can also be transmitted by saliva, nasal secretions, feces and blood. Infections also occur through contact with these body fluids or with contaminated surfaces.

Flu viruses can remain infectious for about one week at human body temperature, over 30 days at 0 °C (32 °F), and indefinitely at very low temperatures (such as lakes in northeast Siberia). Most influenza strains can be inactivated easily by disinfectants and detergents.

Flu spreads around the world in seasonal epidemics, killing millions of people in pandemic years and hundreds of thousands in non-pandemic years. Three influenza pandemics occurred in the 20th century and killed tens of millions of people, with each of these pandemics being caused by the appearance of a new strain of the virus in humans. Often, these new strains result from the spread of an existing flu virus to humans from other animal species.

Since it first killed humans in Asia in the 1990s, a deadly avian strain named H5N1 has posed the greatest risk for a new influenza pandemic; fortunately, this virus has not mutated to a form that spreads easily between people.

Vaccinations against influenza are most commonly given to high-risk humans in industrialized countries and to farmed poultry. The most common human vaccine is the trivalent flu vaccine that contains purified and inactivated material from three viral strains. Typically this vaccine includes material from two influenza A virus subtypes and one influenza B virus strain. A vaccine formulated for one year may be ineffective in the following year, since the influenza virus changes rapidly over time and different strains become dominant. Antiviral drugs can be used to treat influenza, with neuraminidase inhibitors being particularly effective.

The symptoms of human influenza were clearly described by Hippocrates roughly 2400 years ago. Since then, the virus has caused numerous pandemics. Historical data on influenza are difficult to interpret, because the symptoms can be similar to those of other diseases, such as diphtheria, pneumonic plague, typhoid fever, dengue, or typhus. The first convincing record of an influenza pandemic was of an outbreak in 1580, which began in Asia and spread to Europe via Africa. In Rome over 8,000 people were killed, and several Spanish cities were almost wiped out. Pandemics continued sporadically throughout the 17th and 18th centuries, with the pandemic of 1830–1833 being particularly widespread; it infected approximately a quarter of the people exposed.

The most famous and lethal outbreak was the so-called Spanish flu pandemic (type A influenza, H1N1 subtype), which lasted from 1918 to 1919. Older estimates say it killed 40–50 million people while current estimates say 50 million to 100 million people worldwide were killed. This pandemic has been described as "the greatest medical holocaust in history" and may have killed as many people as the Black Death. This huge death toll was caused by an extremely high infection rate of up to 50% and the extreme severity of the symptoms, suspected to be caused by cytokine storms. Indeed, symptoms in 1918 were so unusual that initially influenza was misdiagnosed as dengue, cholera, or typhoid. One observer wrote, "One of the most striking of the complications was hemorrhage from mucous membranes, especially from the nose, stomach, and intestine. Bleeding from the ears and petechial hemorrhages in the skin also occurred." The majority of deaths were from bacterial pneumonia, a secondary infection caused by influenza, but the virus also killed people directly, causing massive hemorrhages and edema in the lung.

The Spanish flu pandemic was truly global, spreading even to the Arctic and remote Pacific islands. The unusually severe disease killed between 2 and 20% of those infected, as opposed to the more usual flu epidemic mortality rate of 0.1%. Another unusual feature of this pandemic was that it mostly killed young adults, with 99% of pandemic influenza deaths occurring in people under 65, and more than half in young adults 20 to 40 years old. This is unusual since influenza is normally most deadly to the very young (under age 2) and the very old (over age 70). The total mortality of the 1918–1919 pandemic is not known, but it is estimated that 2.5% to 5% of the world's population was killed. As many as 25 million may have been killed in the first 25 weeks; in contrast, HIV/AIDS has killed 25 million in its first 25 years.

Later flu pandemics were not so devastating. They included the 1957 Asian Flu (type A, H2N2 strain) and the 1968 Hong Kong Flu (type A, H3N2 strain), but even these smaller outbreaks killed millions of people. In later pandemics antibiotics were available to control secondary infections and this may have helped reduce mortality compared to the Spanish Flu of 1918.

info : wikipedia

Stay Away From Viruses

A virus (from the Latin virus meaning toxin or poison) is a sub-microscopic infectious agent that is unable to grow or reproduce outside a host cell. Virus diseases inflict a heavy illness and economic burden on humans and animals and can devastate agricultural crops. Each viral particle, or virion, consists of genetic material, DNA or RNA, within a protective protein coat called a capsid. Their shape varies from simple helical and icosahedral (round) forms to more complex structures with tails or an envelope. Viruses infect all cellular forms of life, and they are separated into animal, plant and bacterial viruses. It has been argued whether viruses are living organisms. Some consider them non-living as they do not meet all the criteria of the definition of life. For example, unlike most organisms, viruses do not have cells. However, viruses have genes and evolve by natural selection. They have been described as organisms at the edge of life. Viral infections usually results in disease and, in animal hosts, an immune response. Often, the virus is completely eliminated by the immune system. In comparison with antibiotics (which have no effect on viruses) antiviral drugs are generally more specific and more expensive. For some serious viral diseases vaccines, which can produce lifelong immunity, have been developed.

Viral diseases such as rabies, yellow fever and smallpox have affected humans for many centuries. There is hieroglyphical evidence of polio in the ancient Egyptian empire, though the cause of these diseases was unknown at the time. In 1717, Mary Montagu, the wife of an English ambassador to the Ottoman Empire, observed local women inoculating their children against smallpox. In the late 18th century, Edward Jenner observed and studied Miss Sarah Nelmes, a milkmaid who had previously caught cowpox and was subsequently found to be immune to smallpox, a similar, but devastating virus. Jenner developed the first vaccine based on these findings; after lengthy (but successful) vaccination campaigns the World Health Organization (WHO) certified the eradication of smallpox in 1979.

In the late 19th century Charles Chamberland developed a porcelain filter with pores small enough to filter bacteria, yet retain all viable viruses. Dimitri Ivanovski used this filter to study tobacco mosaic virus. He published experiments showing that crushed leaf extracts of infected tobacco plants were still infectious after filtering through such filters. At about the same time, several others documented filterable disease-causing agents, with several independent experiments showing that viruses were different from bacteria, yet they could also cause disease in living organisms. These experiments showed that viruses are orders of magnitudes smaller than bacteria. The term virus was coined by the Dutch microbiologist Martinus Beijerinck who showed, using methods based on the work of Ivanovski, tobacco mosaic disease is caused by something smaller than a bacterium. He developed with the term "contagium vivum fluidum" which means “soluble living germ” as first the idea of the virus.

In the early 20th century, Frederick Twort discovered that bacteria could be attacked by viruses. Felix d'Herelle, working independently, showed that a preparation of viruses caused areas of cellular death on thin cell cultures spread on agar. Counting the dead areas allowed him to estimate the original number of viruses in the suspension. The invention of Electron microscopy provided the first look at viruses. In 1935 Wendell Stanley crystallised the tobacco mosaic virus and found it to be mostly protein. A short time later the virus was separated into protein and nucleic acid parts. In 1939, Max Delbrück and E.L. Ellis demonstrated that, in contrast to cellular organisms, bacteriophage reproduce in "one step", rather than exponentially.

A major problem for early virologists was the inability to propagate viruses on sterile culture media, as is done with cellular microorganisms. This limitation required medical virologists to infect living animals with infectious material, which is dangerous. The first breakthrough came in 1931, when Ernest William Goodpasture demonstrated the growth of influenza and several other viruses in fertile chicken eggs. However, many viruses would not grow in chicken eggs, and a more flexible technique was needed for propagation of viruses. The solution came in 1949 when John Franklin Enders, Thomas H. Weller and Frederick Chapman Robbins together developed a technique to grow polio virus in cultures of living animal cells. Their methods have since been extended and applied to the growth of many viruses and other infectious agents that do not grow on sterile culture media.

info : wikipedia