INFECTIOUS DISEASE

Ebola infection

2012-05-06T18:42:00.006-07:00

The causative agent is Ebola virus. Ebola virus has its origin in Africa. It causes hemorrhagic fever in humans with an extremely high lethality. The most striking symptom is uncontrolled bleeding from any orifice.

Ebola virus is transmitted through contact with patient body fluids. Infectious virions may persist for weeks in the same of recovered patients.

Contaminated needles can also cause the infection. Nosocomial and community-acquired transmission can occur. Transmission through semen may occur up to 7 weeks after clinical recovery.

During infection, the Ebola virus accumulates in high numbers in the liver, spleen, lymph nodes, and lungs, severely damaging these organs during the course of the disease.

The initial symptoms of infection may include flu-like symptoms such as fever, chills, muscle and headaches, nausea, vomiting, loss of appetite, and malaise.

Zaire and Sudan strains produce a disease characterized by multifocal organ necrosis, coagulopathy, extensive visceral effusions, hemorrhagic shock, and death.

As viremia overtakes the immune system, disseminated intravascular coagulopathy occurs and the patient may go into shock or coma.

Ebola infection

SARS

2012-03-21T18:16:00.006-07:00

SARS is one of very dangerous disease of the twenty first century, which include avian flu and Ebola.

SARS or Severe acute respiratory syndrome is a respiratory illness that has been reported in Asia, North America and Europe and is caused by a special kind of virus called a coronavirus named SARS-Cov. It is very infectious which means it is easily spread from one person to another.

The virus remains active and is able to cease infection in both urine and feces for 24 to 48 hours. In the first week, the disease produce fever but few other symptoms. In the second week, pneumonia spread though the lungs.

In the third week, destruction of blood vessels occurred, which was fatal in many cases.

The overall mortality was 3%-6% of people infected, but mortality went up to 40% - 50% in certain area, when people older than 60 were infected.

The symptoms of SARS include high fever, headache, discomfort, body aches, dry cough and the development of pneumonia. SARS is spread by close contact involving respiratory droplets.

The first case of SARS was reported in Asia in February, 2003. In a few months, this disease spread in Europe, South and North America.

SARS

Foodborne Disease Caused by Micro-organisms

2012-01-07T23:54:00.000-08:00

Foodborne disease is a public health problem which comprises a broad group of illnesses.

Among them, gastroenteritis is the most frequent clinical syndrome which can be attributed to a wide range of micro-organisms, including bacteria viruses and parasites.

Usually, the incubation period is short, from 1-2 days to 7 days.

Different degrees in severity are observed, for a mild disease which does not require medical treatment at the more serious illness requiring hospitalization, long term disability and /or death.

The outcome of exposure to foodborne diarrheal pathogens depends on a number of host factors including preexisting immunity, the ability to elicit an immune response, nutrition, age, and non specific host factors.

As a result, the incidence the severity and the lethality of foodborne diarrhea is much higher in some particularly vulnerable segments of the population, including children under five years of age, pregnant women, immuno-compromised people and elderly.

In addition to these well known predisposing conditions, new ones are regularly identified (liver disease for paraheamoliticus septicemia, thalassemia for Yersinia enterocolitica infections).

Serious complications may result from these illnesses including intestinal as well as systemic manifestations, like hemolytic uremic syndrome for 10% of Escherichia coli 0157:H7 infections with bloody diarrhea, Guillain-Barre syndrome (nerve degeneration, slow recovery and severe residual disability) after Campylobacter jejuni infection, reactive arthritis after salmonellosis and chronic toxoplasmic encephalitis.

While diarrhea is the most common syndrome following the consumption of a contaminated food some disease are more serious.

Clinical manifestations of listeriosis include bacteriemia and central nervous system infections, especially in patients with an impairment of T-cell mediated immunity and abortion in pregnant women, with an overall case fatality rate of 25%.

Food borne botulism is a result from the potent toxin by Clostridium botulinum that cause a paralysis of skeletal and respiratory muscles which, when severe may result in death in 8% of cases.

Toxoplasma gondii is also the most frequent cause of lesion in the central nervous system in patients with AIDS.

Hepatitis A is an infectious disease for which age is the most important determinant of morbidity and mortality, with severity of illness and its complications increasing with age.

The durations of illness vary but most cases are symptomatic for three weeks.

Complications during the acute illness phase are unusual, with fulminant hepatitis and death being uncommon.
Foodborne Disease Caused by Micro-organisms

What is infection?

2011-10-16T22:59:00.001-07:00

Humans live in their environment with many other species. Many members of the animal and plant kingdoms are microscopic an can cause human illness, called infection.

Infection is a disease caused by pathogen. An infection is an disease caused by pathogen.

The human body is colonized in the skin and mucosal surfaces with numerous microorganism that form the normal flora of the body.

This organism, far from causing disease, often provide benefit to the host, by competing with potential pathogens for attachment sites and nutrients.

Even potential pathogens can act as colonizers. Staphylococcus aureus, which is capable of causing severe disease, commonly exists in the surface of healthy skin.

It is only when it invades the skin tissues or the blood that it can causes an infectious disease.

Normally, it is the present of the replicating organisms, associate with tissue damage, that defines the conditions as an infection.

Tetanus occurs when Clostridium tetani multiplies on a wound, elaborating neurotoxin tetanospasmin.

Therefore, the term infection refers to the presence and multiplication of microorganisms in the tissue of a host. The host response to this invasion and replication various.

It is the task of the immune system to protect the host against invading infections agents and thereby to prevent infectious disease.

Conversely, the immune system has evolved to provide appropriate defense mechanisms at a various levels of ‘unspecific’ and ’specific’ immune response.
What is infection?

Tetanus

2011-09-13T23:34:00.001-07:00

Tetanus is a frequently fatal disease caused by the bacterium Clostridium tetani.

The disease is caused by the action of a potent neurotoxin produced during the growth of the bacteria in dead tissues.

The disease is characterized by intense painful muscle contractions, sometimes strong enough to break even the strongest bones in the body.

The word tetanus is derived from Greek term tetanus, meaning ‘to contract’.

The continue contraction of the muscle are liable to sudden increase in violence and painful paroxysm, which ceasing, leaving in a comparatively relaxed and easy state.

This disease is everyone worrying about. The repeated exposure of young children to cut scrapes and it provides a continual source of anxiety for parents on unvaccinated children.

Tetanus has been distinguished into two species, the idiopathic, including those cases where the disease appears to arise from some general cause, as exposure it damp or cold; and the traumatic or symptomatic, when it is a remote consequence of a local injury.

People of all ages can get tetanus, But the disease is particularly common and serous in newborn babies. This called neonatal tetanus. Most infants who get the disease die.

Neonatal tetanus is particularly common in rural areas where most deliveries are at home without adequate sterile procedures.

The organism responsible for tetanus is found in soils and the intestinal tracts of animals.
Tetanus

Flu Viral Infection

2011-07-19T17:09:00.000-07:00

Influenza viruses have special features that can over power a body’s immune system. It affects respiratory tract – nose, throat, bronchial tubes and lungs.

First, influenza virus are efficient travelers.

Second, they have an amazing ability to copy themselves.

And third, flu viruses are unique in that once a strain has spread in a population, its structure changes and it then is capable of causing a new form of flu because the antibodies produces to combat the original virus are not effective against the new form.

An entirely new strain appears about every 10 years.

Not only do influenza viruses travel easily from person to person, they do so secretly for part of the time.

A person with the flu may be contagious for several days before he or she know it.

When an infected person coughs or sneezes, he or she releases tiny droplets of water from the mouth and nose.

The most common way to catch the flu is by inhaling that tiny droplets. Less often it is spread when the person touch a surface such as a faucet handle or phone that has the virus on it and then touch his own mouth, nose, or eyes.

The virus’s ability to turn normal human or animal host cells into flu-copying machines is another reason influenza can take over immune systems.

After an incubation period of 1 to 4 days, people infected with influenza virus develop an abrupt fever, headache, sore throat and dry cough that can in some cases progress to viral pneumonia, respiratory failure and death.
Flu Viral Infection

Infective Parasitic Pathogen: Toxoplasma gondii

2011-07-17T18:00:00.000-07:00

Toxoplasma gondii is a protozoan parasite which can be transmitted by fecal-oral contamination. Cats are the original hosts for this protozoa. They excrete microscopic in active forms of this protozoa in their feces. Farm animals (notably sheep and pigs) become infected by consuming feed and water contaminated by barn cats’ fecal material.

Active forms of this parasite then multiply with the farm animals and encyst themselves in the brain, heart muscle, other skeletal muscle, and liver. The cysts are microscopic and can exists as long as the farm animal lives.

When these animals are slaughtered to provide meat, the raw meat contains the cysts which can then infected humans if it is eaten raw or not heated sufficiently to inactive various forms of this parasite. About 30% of all fresh pork is infected and is the main meat source of Toxoplasma gondii in the United Sates.

If cutting and grinding equipment is not thoroughly washed and sanitized, other raw meats such as ground beef can also become contaminated. About 5% of the ground beef sold in supermarket contains some pork because the grinding equipment is not properly cleaned between grinding operations. Cysts of this protozoa are also found in wild game meats such as elk, moose, and venison.

Symptoms of the disease in humans are fever, muscle aches, headaches, loss of appetite and sore throat. Other symptoms will appear, depending upon the internal organs involved. In pregnant women, these parasites can be carried by way of the placenta to fetal tissue. If fetuses are infected, spontaneous abortions may occur. Most infected infants show no obvious symptoms at birth, but will show signs of eye damage and mental retardation later in life.

It is estimated that there are over 3,300 cases of congenital Toxoplasmosis each year resulting in 450 deaths of infants and young children. Other surviving infected children are mentally retarded as a result of this parasitic infection.
Infective Parasitic Pathogen: Toxoplasma gondii

Campylobacteriosis symptoms

2011-06-30T21:36:00.001-07:00

Campylobacteriosis is the leading cause of diarrhea in the developing world, with the number of cases exceeding those of salmonellosis and shigellosis.

Campylobacteriosis is the name of the illness caused by C. jejuni. It is also often known as campylobacter enteritis or gastroenteritis.

Symptoms of illness caused by Campylobacter jejuni include: diarrhea (which may be quite severe and bloody), fever, headache, nausea and severe abdominal pain.

The illness may linger for 1 to 2 weeks and there may be a relapse when recovery seems imminent.

This illness is more severe in adults than in children and can sometimes lead to a form of reactive arthritis.

Symptoms of the illness are similar to other food borne illness caused by Salmonellosis spp, Shigella spp and Escherichia coli.
Campylobacteriosis symptoms

Gastroenteritis

2011-05-08T06:58:00.000-07:00

Gastroenteritis is one of the most common illness of humans. It is an inflammation of the stomach and intestinal lining.

Eating chemical toxins in food, drinking excessive alcohol, food allergies, foodborne illness, intestinal viruses, cathartics and other drugs can cause gastroenteritis.

Bacteria, viruses and protozoa all of which can be transmitted through contaminated food as well as from person to person.

Gastroenteritis is an acute diarrheal disease that affects both children and adults throughout the developed and developing world.

In developing countries, acute diarrheal disease illness remain one of the major causes of long term morbidity and mortality because for the majority of the population, access to clean water and safe food sources are limited.

Acute gastroenteritis causes almost 3 million deaths each year worldwide, mostly among children under 5 years of age in developing countries.

There are thousands of different organism that can cause gastroenteritis. In the United States, it is usually caused by viruses and less commonly by bacteria.

Acute gastroenteritis can follow the ingestion of pathogenic microorganisms or toxins produced by these agents.

Ingestion of contaminated food or drink is most common, but swimming or bathing in contaminated water can also result in exposure, particularly among travelers.
Gastroenteritis

Acinetobacter infection

2011-03-24T20:21:00.000-07:00

Acinetobacter is a group of gram positive, nonmotile bacteria most commonly found in the soil or water.

This bacterium has been isolated from various types of opportunistic infection. Various factors predisposing to severe infections, such as underlying disease, malignancy, burns or major surgery, have been indentified and are common to many other pathogens.

Acinetobacter most often colonize patients in intensive care units, particularly those with devices such as endotracheal tubes, indwelling urinary catheters, intravascular catheters or surgical drains.

Risk factors include recent surgery, antibiotic therapy, and immunosuppresion. Patients with serious underlying illnesses can become colonized rapidly with Acinetobacter from highly contaminated environment.

Acinetobacter is primarily spread from person to person and from fomites, such as medical equipment. It is possible that aerosolization is a route of exposure.

Acinetobacter spp can cause infection in virtually every organ system: septicemia, urinary tract infections, eye infections, meningitis, skin infections, pneumonia and endocarditis.
Acinetobacter infection

Food Infection Diseases

2010-12-12T23:52:00.000-08:00

Food Infection Diseases
The cause of food borne diseases is mainly the ingestion of infected food. Apart from gastrointestinal problems and related illness due to improper diet, nutritional deficiencies and over heating, the causes of food borne illness may be due to either
1- Food Infection
2- Food Intoxication

The entry of pathogenic organisms and parasites into the body and the reaction of the body to the presence of organisms or their metabolites cause of the body to the presence of organisms or their metabolites cause food infection.

Pathogenic organisms make their entry through the food chain i.e. by consuming foods contaminated with such organisms. Bacterial food infection refers to food borne illness cause by the entry of bacteria into the body.

Food intoxication or poisoning is cause by consuming food contaminated with toxic substances.

Food infections may be broadly sub classified into two types.

1- Those in which the contaminated food does not ordinarily support the growth of the pathogenic organisms but merely carries them. Such food infections include diseases such as diphtheria, dysentery, typhoid, cholera, tuberculosis, infectious hepatitis, etc.
2- Food infections in which the food serves as a culture medium for the growth of pathogens to increase in number and cause infection when such food is consumed leading to diseases such as salmonellosis, shigellosis, gastroenteritis, etc.

Food infections can lead to outbreak of diseases in epidemic propositions.
Food Infection Diseases

The Quinine Story

2010-08-25T03:04:00.001-07:00

The Quinine Story
Ever since is acceptance in 1640 as a proven remedy for the malaria disease, quinine has been the mainstay of malaria treatment and still is today.

Having observed Peruvians treating malaria successfully, Jesuit priests living in Peru returned to Europe with the bark of certain tree that, when boiled and the water drink, greatly improved the survival chances of a malaria victim.

Once introduced to Europe, cinchona (as it was then known) became the drug of choice after use by such famous patients as Charles II and the Archduke Leopold.

Despite its bitter taste and the fact that it sometimes produced deafness, nausea and vomiting, or that its method of action was still mysterious, quinine became known as a miraculous drug.
Its use was linked with serious risks including its association with blackwater fever, an occasional complication of malaria, but known to be one of the commonest causes of death among expatriates in Africa.

It is suspected that irregular doses of quinine used as a prophylactic may have caused this much feared disease.

Today, quinine taken with tetracycline is often the last drug used, after other drugs failed to quell malaria.
The Quinine Story

Parasites as pathogens

2010-07-09T02:01:00.000-07:00

Parasites as pathogens
The true definition of a parasite is an organism that lives on or in another organisms, deriving benefit from it but providing nothing in return.

Nor all ‘parasites’ cause disease; organisms such as Entamoeba dispar, a protozoan, live in the human gut without causing disease and are thus colonizers.

Around 500 million individuals in the world are infected with amebiasis caused primarily (90%) by E. dispar.

This closely related species E. histolytica is capable of invading the bowel wall, causing colitis and abscesses in the liver, brain and other tissues.

E. histolytica is a powerful pathogen that uses proteases to destroy hosts’ tissues, kill some hosts’ cells and “phagocyte” red cells.

Multicellular parasites such as schistosomes may also be pathogens. In the past, diseases caused by metazoan parasites, such as schistosomiasis, were sometimes called infestations. Nowadays all parasitic diseases are called infection.
Parasites as pathogens

Short History of Tuberculosis

2010-06-07T08:35:00.001-07:00

Short History of Tuberculosis
In the Paleolithic period, people lived as wanderers, did not settle in villages or permanent locations, and do not congregate in large groups.

While tuberculosis may have occurred sporadically, it an other infections disease probably did not occur in epidemic form.

Beginning in about 8000 BC, humans developed primitive agricultural techniques that allowed settlement in permanent sites and with this development came the domestication of cattle, swine and sheep.

In all probability, tuberculosis occurred more frequently in this setting, but it nevertheless remained rare.

Tuberculosis probably occurred as an endemic disease among animals long before it affected humans. Mycobacterium bovis was the most likely infecting organism and the first human infections may have been with Mycobacterium bovis.

Since Mycobacterium tuberculosis infects all primate species, it is also possible that this species existed in subhuman primates before it became established in humans.

Tuberculosis probably occurred as a sporadic and unimportant disease of humans in their early history. Epidemic spread began slowly with increasing population density.

This spread and the selective pressure it has exerted have occurred at different times around the globe.

The epidemic slowly spread worldwide as a result of infected European travelling to and colonizing distant sites.

In the 1700s and early 1800s tuberculosis prevalence peaked in Western Europe and the United States and was undoubtedly the largest cause of death.

100 to 200 years later it had spread in full force to Eastern Europe, Asia, Africa and South America.

1.6 millions death worldwide due to tuberculosis in year 2002 alone. Currently tuberculosis kills 1.8 million people each year. However scientist believed that can be averted by 2050 with better testing, drugs and vaccines.

Treatment from 1995 to 2008 saved six millions lives. However 36 millions infected with tuberculosis during 1995-2008 were cured and incidence of the lung wasting disease has begun to regress, but only by about one percent per year.
Short History of Tuberculosis

Theories about Malaria

2010-05-07T09:07:00.000-07:00

Theories about Malaria
It took a long time for the connection between malaria and swampy ground to be made.

Medieval beliefs that planet and comets rained down a fever poison or that electrical storms were responsible, had to be overcome first.

During the first half of the nineteenth century it was also believed that dew falling on the decks of ships before sunrise would produce small insects that carried the fever.

It was further thought that preferred targets were of fair complexion and were fond of alcohol.

From the middle ages up until just over 100 years ago, the dominant theory governing malaria transmission concerned the fact that swamp air contained chemical poisons released from rotting wood.

To avoid this, houses were built facing away from wetlands and lakes, and double storey houses were referred as it was thought that the air did not rise much above ground level.

Known in the Middles Ages as ‘the ague’, malaria’s connection with marshy ground was entrenched when it was eventually given the Latin name that means ‘bad air’, i.e. mal’aria.
Theories about Malaria

The definition of Pathogen

2010-04-14T03:48:00.001-07:00

The definition of Pathogen
A pathogen is defined as any organism capable of invading the body and causing diseases. Such an organism is said to be pathogenic.

Robert Koch isolated and identified organisms such as Mycobacterium tuberculosis and Bacillus anthracis, where the isolation of the organism only occurred in the presence of disease.

It is easy to define these bacteria as pathogens. They also fulfill Koch’s further definition of a pathogen, that introduction of a pure culture of the organism into a health host can cause the disease.

This definition works well for many bacteria, but does not fully describe the complex interactions between microbes and humans which more recent understanding has revealed.

For instance, Escherichia coli is found in huge numbers in the healthy human bowel, and could therefore be defined as non-pathogenic.

E. coli is also an important cause of diarrheal disease and potent enterotoxin and other pathogenicity determinants have been described on some strains.

E. coli can therefore behave as a pathogen or as a colonizer, depending on various circumstances.

Changes in medical practice mean that increasing numbers of patients are immunocompromised as the result of either disease or treatments.

In such patients organisms which are usually non-pathogenic, such as saprophytic fungi, may act as pathogens.

Intensive therapy medicine, with insertion of intravascular cannulae allows Staphylococcus epidermis, a normal part of the skin flora, to enter the cannula and cause blood borne infection: behaving as a pathogen.
The definition of Pathogen

Immunity factor in diarrheal diseases

2010-03-21T17:46:00.000-07:00

Immunity factor in diarrheal diseases
Immunity plays an important role in susceptibility to enteropathogens. Maternal antibody is provided to the infant through breast milk and this protects against a variety of enteric infections.

Transplacental antibody may also play a role in some. Immunity is actively acquired by the individual who has a diarrheal disease or in some cases even an asymptomatic infection.

There is also evidence that competence of the immune system can be compromised, such as by macronutrient deficiencies, reducing the resistance to enteric infection.

Immunocompetence in a child can be compromised by previous viral infection, such as measles or influenza, or by other infections, such as tuberculosis or typhoid fever.

These infections , along with micronutrient deficiencies, could place individual at a greater risk of diarrhea or of more severe illness through alteration in immune function or by other mechanisms.

Cholera was the first diarrheal disease for which a vaccine was available . A prenatal cholera provides approximately 50% protection lasting for less than 6 months. New killed or live V. cholera vaccines may offer greater efficiency and duration of protection.
Immunity factor in diarrheal diseases

HIV/AIDS

2010-03-02T21:33:00.001-08:00

HIV/AIDS
AIDS stands for “acquired immunodeficiency syndrome” (a syndrome being a cluster of medical conditions).

AIDS is caused y the human immunodeficiency virus, which weakens and then destroy the body’s immune systems.

HIV/AIDS has spread in the last two decades, causing massive human death and suffering, particularly in the developing world.

There is a growing recognition that HIV/AIDS is not just a serious heath issue in developing countries, but a major development catastrophe that threatens to dismantle the social and economics achievement of the past half century.

HIV/AIDS is a fatal, sexually transmitted disease or infection (STD). Once a person is infected with HIV, he or she is infected for life.

In all but a very small proportion of cases HIV/AIDS destroys a person’s immune system.

The time between becoming HIV positive and the onset of AIDS varies.

In industrialize countries, the average time between infection with HIV and the appearance of symptoms is about 10 years, but in the poorest countries of the world, without access to proper care, the time is sometimes as short as five years.

One an HIV infected person’s immune system is severely damaged, he or she becomes vulnerable in life threatening “opportunistic infections” and is diagnosed as having AIDS.

Not everybody is equally likely to become infected with HIV and to transmitted to others.

Like other STDs, HIV is difficult to spread except by sex or other direct contact with the bodily fluids of an infected person.

About three quarters of HIV transmission worldwide occurs through sexual intercourse involve sexual relations between men.

The other modes of HIV transmission are transfusion of contaminated blood products, reuse of contaminated syringes by injecting drug users, infection via birth or nursing from an HIV-positive other to her child during pregnancy, childbirth, or breast feeding, and reuse of needle in medical settings.

HIV cannot be transmitted y a sneeze, a handshake or other causal catch.
HIV/AIDS

Lower respiratory tract infection

2010-02-16T21:11:00.000-08:00

Lower respiratory tract infection
The principal function of the respiratory tract is gas exchange. It is therefore expose to the gaseous environment continuing particulate organic material such as bacteria, viruses and spores.

The entire respiratory tract is constantly exposed to air but the majority of particles are filtered out in the nasal hairs and by inertial impaction with mucus-covered surfaces in the posterior nasopharynx.

The epiglottis, its closure reflex and the cough reflex all reduce the risk of microorganisms reaching the lower respiratory tract.

Particles small enough to reach the trachea and bronchi stick to the respiratory mucus lining their walls and are propelled towards the oropharynx by the action of cilia (the mucociliary escalator).

Antimicrobial factors present to respiratory secretions further disable inhaled microorganisms.

They include lysozyme, lactoferrine and secretory IgA.

Particles in the size range 5-10 um may penetrate further into the lungs and even reach the alveolar air spaces.

Alveolar macrophages are available there to phagocytes potential pathogens. If these are overwhelmed, neutrophils can be recruited via the inflammatory response.

The defenses of the respiratory tract are a reflection of its vulnerability to microbial attack.

Acquisition of microbial pathogens is primarily by inhalation, but aspiration and mucosal and haematogenous spread also occur.

Individuals with healthy lungs rarely have any bacteria beyond the carina.

Respiratory pathogens have developed a range of strategies to overcome host defences. Influenza virus for example has specific surface antigens that adhere to mucosal epithelial cells.

The virus also undergoes periodic genetic reassortment , resulting in expression of novel adhesions to which the general population has no effective immunity.

Streptococcus pneumonia and Haemophilus influence both produce an enzymes (IgA protease) capable of disabling mucosal IgA.

Both of these species , other capsulated bacteria and mycobacteria are all resistant to phagocytosis. Penetration of local tissue is usually required before damage occurs. Although viruses using the common cold appear to be an exception.
Lower respiratory tract infection

Infectious Mononucleosis

2010-01-31T07:01:00.001-08:00

Infectious Mononucleosis
Infectious mononucleosis is an acute disease due to infection by the Epstein-Barr virus (EBV) and characterized by the tetrad of fever pharyngitis, lymphocytosis and fatigue.

Primary EBV infection may occur during childhood, adolescence or adulthood.

Approximately 50% of all children, the infection is subclinical.

When this infection occurs in adolescents and adults, it may be either subclinical or it may be recognized as infectious mononucleosis.

Once infected with virus, persons remain asymptomatically infected for life, and the virus is shed intermittently from the oropharynx.

The route of transmission for this infection is, therefore by oropharyngeal contact (usually kissing) between an uninfected and a healthy EBV-seropositive individual who is asymptomatically shedding the virus.

The virus, after having been acquired first binds to and infects the nasopharyngeal cells and then the B-lymphocytes.

Circulating B-lymphocytes carry the virus throughout the body, producing a generalized infection of lymphoid tissues.

The activated B-cells stimulate the proliferation of specific killer T-cells, giving rise to an atypical lymphocytosis associated with primary EBV infection.

These killer T-lymphocytes destroy virally infected B-cells.

Another type of T-cells released are the suppressor T-cells which inhibit the B-cell production to immunoglobulins.

The onset of this disease is marked by malaise lasting from a few days to a week followed by fever, pharyngitis (which may be severe) and adenopathy.

In other cases, enlargement of a solitary lymph node or a group of nodes may be the sole clinical manifestation.

Splenomegaly due to hyperplasia of the red pulp is observed in about 50% of cases. Because of the risk of splenic rupture, heavy lifting and contact sports should be avoided for two months after presentation, even if there is no lasting splenomegaly.
Infectious Mononucleosis

What is Tamiflu?

2010-01-14T20:05:00.000-08:00

What is Tamiflu?
This medicine contains as active ingredient oxeltamivir phosphate used in the treatment of symptoms of influenza (flu).

Tamiflu is one of the classes of antiviral drugs called neuraminidase inhibitors.

This medicine speeds recovery from the flu. When started during the first 2 days of the illness, it hastens improvement by at least a day.

It also can prevent the flu of treatment is started within 2 days after exposure to a flu victim.

As the flu virus takes hold in the body, it forms new copies of itself and spreads form cell to cell.

Neuraminidase inhibitors fight the virus by preventing the release of new copies from infected cells

Tamiflu is taken in liquid or capsule form.

Tamiflu can prevent the flu as long as continue taking this medication but getting a yearly flu shot is still the best way of avoiding the disease entirely.

For older adult, those in high risk situations such as health-care work, and people with an immune deficiency or respiratory disease, vaccination remains a must.

To provide any benefit, Tamiflu must be started within two days of the onset of symptoms or exposure to the flu.

If have the flu, continue taking it twice daily for 5 days, even of started to feel better.

To prevent the flu take it once a day for at least 7 days. Protection lasts as the medicine taken.

Unless otherwise directed by doctor or pharmacist, take this medication as directed. Do not take more of them and do not take them more often then recommended on the label.
What is Tamiflu?

Immune System

2009-12-15T22:47:00.001-08:00

Immune System
Your body’s immune system is a very complicated network of organs and cells that work together to fight deadly intruders called antigens, which are any organism that could make you sick, like bacteria, microbes, parasites and viruses.

An antigen, such as a virus, is a virus, is a parasite.

A parasite cannot survive by itself – if needs to feed off of an animal, human, or plant (also called the host) to survive.

Once inside the cells of a host, a virus tries to become active and multiply. If it successful it can eventually create so many copies of itself that it causes the cell to burst releasing the virus into the body.

Then the virus finds more cells on your body in which to live. This process can continue on and on, until the virus has attacked enough cells to make you ill.

However, a healthy and strong immune system can usually kill any viruses before they multiply to such a damaging degree.
Immune System

A Historical Perspective of Dengue

2009-11-14T21:20:00.000-08:00

A historical Perspective of Dengue
The story of dengue in many ways starts in the Americas.

Dr. Benjamin Rush made the first good clinical description of dengue.

He was in charge of hospitals under General George Washington in the Oriental Army and described for dengue outbreak in Philadelphia in 1780:

“This fever generally came on with rigor, but seldom with a regularly chilly fit. The pains which accompanied this fever were exquisitely severe in the head, back and limbs.

The pains in the head were sometimes in the back parts of it, and at other times they occupied only the eyeballs.

A few complained of their flesh being sore to the touch, in very part of the body. Its general name among all classes of people was the break-bone fever.”

Dengue today presents with the same fever, headache, eye pain, myalgia and arthralgia.

The US military’s dengue research efforts started just after the Spanish-America War, sparked by the very many dengue causalities in the Philippines.

A dengue commission was established in 1900, and Ashburn and Craig were sent to the Philippines to determine the etiology of dengue and to devise countermeasures.

Although a series of experiments they deduced that dengue was caused by “an ultra microscopic and non-filterable agent,” or a virus.

Ashburn and Craig confirmed that virus could be transmitted from person to person by both mosquito and by syringe; they made careful description of the disease to include leucopenia.

Important for vaccine development, they demonstrated that immunity following infection was absolute; they could only make healthy volunteers with dengue one time.

During World War II, Japan and the United States of America had large dengue research programs.

Dr. Hotta and Dr. Kimura in Japan isolated the dengue serotype 1 virus (DENV-1) shortly before Dr. Sabin and Dr. Schlesinger did so in Hawaii.

In the 1950s, the face of dengue changed dramatically with the widespread recognition of DHF. The army and the Air Force sent Dr. Bill Hammond to investigate the 1956 outbreak of hemorrhagic fever in the Philippines.

He worked with Philippines and Thai scientist to isolate DENV-3 and DENV-4.

The most important pathological process that distinguished DHF from dengue is plasma leakages that can lead to shock and death.

Untreated, DHF has a mortality rate of around 10%. With careful fluid management, however, mortality rates drop to below 1%.

DHF can occur in any age group, but it is most common among children living in dengue hyperendemic areas.
A historical Perspective of Dengue

Anthrax: The Disease and the History

2009-10-25T20:38:00.000-07:00

Anthrax: The Disease and the History
Anthrax is a peracute, acute or sub-acute disease primarily affecting herbivores but also encountered in other mammals, including humans, and occasionally birds.

The words ‘anthrax’ is derived from the Greek anthrakos, meaning coal, referring o the characteristics eschar in the human cutaneous form of the disease.

The familiar name ‘black bane’ and the French and Italian names for the disease charbon and carbonchio, similarly reflect this manifestation.

Names in other languages and older English names refer to other of its significant manifestations or to its sources of infection, viz Milzbrand (German) and miltvuur (Duth), meaning ‘spleen fire’, pustula maligna (Spanish), Bradford disease, woolsorter’s disease, ragpicker’s disease and so on.
Its numerous synonyms in many national languages and local dialects reflect the historical familiarity with the different syndromes before it was realized that they were manifestations of one etiological agent, Bacillus anthracis.

Fifth and sixth plaques of Egypt in the time of Moses are thought by some to have represented the earliest historical; reports of the anthrax due to respectively to systemic and cutaneous forms of the disease.

Anthrax appears to have featured in Asia Minor at the time of Siege of Troy (ca. 1200 BC) an description of the typical symptoms in the writing of Homer (ca. 1000 BC), Hippocrates (ca. 400 BC), Varro (116 – 27 BC), Virgil (70 – 19 BC and Galen (ca. 200 AD) indicate that the Greeks and Romans were well acquainted with it.

Scientifically reports began with the descriptions of malignant pustule and the disease in animals in 1700s.

The nineteenth century saw anthrax as the first disease of man and animals shown to be caused by a microorganism and as the disease on which much of the original work on bacteria and vaccines was done.
Anthrax: The Disease and the History

Measles

2009-10-04T19:41:00.001-07:00

Measles
Measles is a viral disease most commonly affecting school age children, although adults contact the ease as well.

There are two main varieties: German measles and common measles.

There is an immunization but if there are existing conditions, they may be complications.

German measles (rubella) is caused by a virus and has a rapid recovery period, but the disease must run its course and there is little that can be done medically for its treatment, German measles is a mild illness, alarming only to pregnant women.

If a woman contracts German measles during the early months of pregnancy the newborn can suffer from such malformations as heart defect, deafness, mental retardation, and blindness.

Symptoms of German measles may include fever headache and stiff joints (mainly in the neck), although most people seldom complain of any symptoms.

A rash that lasts for about three days appears on the arms, chest and forehead.

Lotion may be applied to the rash to relieve itching, and the patient should stay away from other people to avoid spreading the disease.

Common measles (rubeola) is a highly contagious disease spread by droplets from the nose throat and mouth.

The first symptoms of common measles are a fever that lasts for a couple of days followed by a cough, runny nose and inflammation of the eyes.

Stomach pains, diarrhea, and vomiting may also occur. Within twenty forty-eight hours, small red spots with white centers appear in the inside of the cheeks.

A rash which is first seen on the face and upper neck and then spreads down the back and trunk and then to the limbs, usually appears three to five days after the onset of the first symptoms.

As the rash spreads fever goes down. After about five days, the rash fades in the same order it appeared. Common measles may have been serious complications, such as ear infections, pneumonia, encephalitis and injury to the nervous system.
Measles