Tag Archives: infections

Infectious Conjunctivitis

The inner surface of the eyelid consists of a thin membrane called the conjunctiva. It is one of the places tears are produced, though not to the same extent as in the tear ducts; these tears serve as a lubricant to reduce friction between the eye and eyelid. This layer also helps protect the eye from dust and microorganisms. Despite its usefulness, the conjunctiva is almost never noticed by people until an infection or an allergic reaction causes the inflammation that results in the redness, itching, burning, and sensitivity to light characteristic of conjunctivitis, or pinkeye.

Conjunctivitis can be caused by a viral or bacterial infection, chemical exposure, irritants such as sand or stray eyelashes, or an allergic reaction. Rubbing the eyes makes any form of pinkeye worse, but especially when a chemical or other irritant, or an allergy, is the cause. Bacterial conjunctivitis is possibly the most recognizable form, causing a greenish-yellow discharge that is responsible for a "stuck shut" feeling. Sometimes, pinkeye due to bacterial infection can be associated with a sexually transmitted disease, although this accounts for a very small percentage of eye infections. Bacterial conjunctivitis, left untreated, can cause long-term damage to eye health.

Both the bacterial and viral forms of pinkeye are highly contagious. Someone who has pinkeye should be aware of that and try to take precautions to avoid infecting others, if only out of courtesy. For everyone else, prevention an play a big role in avoiding the disease. Rubbing the eyes can cause or worsen any eye irritation already present, whatever the cause, as well as bringing any microbes on the hands into contact with the eye. Regular hand-washing, such as after cooking using the restroom, or coming in from outside—particularly after using public transit—can also make a significant difference.

Once someone has pinkeye, it is likely to go away on its own faster than most treatments are likely to be effective, particularly it there is no bacterial infection. However, people who have or who have recently had a bout of pinkeye should not wear contact lenses until it is completely cleared up. Eye drops can provide some relief and mitigate irritation.

Athlete’s Foot

The fungus Trychophyton lives on wet surfaces. But it thrives on human skin, particularly the feet, where it is responsible for the painful itching known as athlete’s foot that affects about 15 percent of the population. The name comes from the fact that a common place for transmission is locker rooms—the infected person showers, walks on the locker room floor, and deposits the fungus there, and then another person walks barefoot on the surface and picks it up, becoming infected. Once a person has acquired the fungus, it may be anywhere on the body that is warm and moist.

A type of ringworm, athlete’s foot produces itching between the toes and in other infected areas, as well as a scaly red rash and often ulcers and sores. It can easily spread to the hand if the sufferer scratches or picks at the itchy scales. One common variety of the condition causes dryness and scaling, resembling eczema, that starts on the soles of the feet and goes up the sides towards the ankles; this is known as "moccasin foot" or "plantar athlete’s foot." In addition, some people have an allergic reaction to the fungus that is separate from the effects of the infection.

In addition to walking barefoot in places like locker rooms and saunas, risk factors include tight shoes and damp socks, as well as sharing socks with someone who has been infected. Athlete’s foot fungus can even spread on carpets. It can easy to avoid, experts say, by such preventative measures as wearing sandals or shower shoes in places with damp surfaces; washing the feet regularly, drying them thoroughly, and keeping them dry; and rotating footwear and changing it regularly.

As is often the case with fungal infections such as ringworm, athlete’s foot can be difficult to treat, and is likely to require professional medical care. Keeping the feet clean and dry is a key factor, but an infected person’s towels should not be used more than once without being thoroughly washed until after the infection has cleared. Topical as well as oral anti-fungal medications are often prescribed to eliminate the Trychophyton fungus.

Chagas Disease Often Goes Unrecognized

Parasitic infections are rare in the United States, but one, called Chagas disease, is believed to be active in several southern states and as far north as the Washington, D.C., area. Also known as American trypanosomiasis, Chagas disease—named for the Brazilian doctor who first identified it more than a century ago—affects as many as 8 million people worldwide, mostly in Latin America, but increasingly in the United States and even Canada. The parasite, Trypanosoma cruzi, that causes the disease is spread through insect bites, as well as from pregnant women to their children, and though blood transfusions and organ transplants if they aren’t sufficiently screened.

Screening, sadly, is rare in the U.S., as doctors in this country are not all aware of the disease’s expanded range. Although Chagas disease can be fatal if let unchecked, it is quite easily cured if caught early. It is usually asymptomatic in its early stages, however, so screening for anyone who is at risk is important. Crudely constructed buildings in warm climates—mud or thatch structures, for example—often house the bugs that carry the parasite, so anyone who has spent significant amounts of time in such a building may be at risk. People who do show symptoms, such as eyelid swelling, enlargement of the liver or spleen, fever, fatigue, or rash should also be tested, especially if they’ve been in Central America.

Left untreated, Chagas disease can lead to colon inflammation or heart failure. This can happen years after the initial infection if it isn’t properly treated. Treatment involves anti-parasitic medication, and is highly likely to be effective if done in the immediate aftermath on the initial infection, during he first few weeks. However it is sometimes successful after the initial phase has passed but before the parasite has settled in. Once the disease has become chronic, the only real medical option is management of the symptoms, such as heart medication for patients whose hearts are effected. There is no vaccine currently available for the disease, and prevention generally involves using nets and insecticides to try to eliminate the insects that carry the disease.


The 19th-century French chemist and microbiologist Louis Pasteur was prolific in his discoveries, but today, 119 years after he died at age 72, he is remembered primarily for a handful. Pasteur invented the food preservation process that bears his name. He is responsible for discoveries, such as the nature of bacteria, that established the field of microbiology; he was among the first scientists to apply that understanding to the question of how diseases are transmitted. And it was Louis Pasteur who developed the first vaccine for rabies, a usually fatal viral disease that causes inflammation in the brain.

Rabies is transmitted from animals to humans—and from animals to other animals—through saliva, which is mostly passed through bites. When an animal with rabies bites another animal, the virus is transmitted. One of the effects of rabies is a tendency to violence, including biting. Although dogs are both the prototypical vector and the most common worldwide, in the Americas, bat bites are actually more often the culprit. However, any small mammal could be carrying rabies. There are about 7,000 cases a year in the United States.

Prevention is best effective at the source, but often the animals that transmit the disease are feral if not actually wild, which presents an obstacle to finding and vaccinating all animals that could potentially spread rabies. That is why people are advised to avoid wild or feral animals when possible, and admire them from a distance. Even strays can be dangerous if they’ve been stray for a significant amount of time.

The reason there is such a focus on prevention is because there is no cure; if the disease is allowed to develop, it is almost certainly fatal. Fortunately, there is a certain amount of lag time between the bite and the disease taking hold during which measures can be taken that may save the patient’s life. Post-exposure prophylaxis can be used to try to ensure the disease never comes to pass. This involves cleaning the wound and administering rabies vaccine as soon as possible.

If symptoms do appear, there is still a slim possibility of saving the patient. A procedure called the Milwaukee Protocol, after the city where it was created, has been used with limited success, though the six patients who recovered since the procedure was created in 2004 is more than had recovered from rabies in all of human history until then. It involves anti-viral drugs administered to a patient in an induced coma.


Lockjaw isn’t how rich people talk; it’s actually a name for tetanus, a disease resulting from a neurotoxin called tetanospasmin produced by bacteria that live primarily in soil and dust. The neurotoxin causes muscle contractions in the neck and jaw, which eventually makes breathing impossible. The bacterial spores are contracted through puncture wounds in environments with dirt or dust, particularly if other bacteria are present and the injury was caused by a foreign object, such as a splinter, that gets lodged in the body.

It is possible for tetanus to develop from a gunshot wound, particularly if the bullet doesn’t go all the way through. Tattoos and body piercing with unclean equipment are also linked with tetanus, which is one reason illegal tattoos can be dangerous. The bacteria thrives best in really deep cuts, but any wound should be cleaned thoroughly as soon as possible to reduce the chance of infection.

In addition to cleaning the wound, someone with a particularly high-risk injury—one that occurs outdoors, involves soil or manure, or occurs in a dirty or dusty environment, as well as animal or human bites—should get vaccinated against tetanus if they haven’t been within the preceding five years. Children are routinely vaccinated for tetanus—generally combined with the diphtheria and pertussis vaccines—but the protection conferred by the shot fades, and boosters are needed about every ten years. Even if someone has been vaccinated, post-exposure prophylaxis, a shot after an injury that could result in tetanus, should be given when necessary. The fight against tetanus is particularly skewed towards prevention as opposed to treatment; prevention is both easier and more effective than addressing the infection once it has already occurred.

Vaccination is generally effective: fewer than 50 cases of tetanus occur annually in the United States. This success is all the more remarkable considering that post-exposure shots can take up to two weeks to reach full effectiveness. In some cases, doctors are advised to give the patient immune cells to jumpstart the response to the infection. People who do get infected will get stiffening of the facial muscles, and then the stiffness extends downward. As many as three-fourths of patients with tetanus died in years past, but with vaccination available the rate has fallen below 15 percent.

Detecting Sepsis

Infections, indirectly if not directly, cause a substantial amount of strife. The pathogen can get into the bloodstream and cause high fever, flushed skin, fast heart rate, low blood pressure, delirium, and swelling of the whole body that can continue even once the infectious agent itself is entirely gone. This condition is known as sepsis, and if not properly treated, it can be fatal. In all, more people die each year from sepsis than from prostate cancer, breast cancer, and AIDS put together; according to a study released earlier this year, only one in ten hospital patients have sepsis, but it is responsible for half of all hospital deaths.

Sepsis is not always apparent until it is already occurring; there are few warning signs, though patients with certain conditions are more prone to developing it. That means it is especially important for doctors and other health care personnel to be alert, looking out for signs. One factor that makes a tremendous difference in survival rates, researchers have found, is how often the staff at a particular hospital is called on to treat patients with sepsis. Hospitals with high volume of sepsis patients treated it more effectively, overall, than hospitals in which it was a rarer occurrence, and at approximately the same cost per patient. The mortality rate for sepsis at busier hospitals was nearly 25 percent lower.

Testing for sepsis is an important part of providing treatment. Unfortunately, testing can take a long time, time health care professionals don't always have. Researchers have recently found a biomarker—a protein or other chemical characteristic of a condition, found in the blood of people who have it—that may make it possible to find sepsis with a simple blood test. That means more cases caught in the early, more tractable stages, and it means getting patients the treatment they need in hours, rather than days. The blood test, if it proves effective, would also be more precise, reducing guesswork and curtailing the role of intuition and fallible judgment.

In addition to better testing, more effective treatment may be available in the near future. A protein found in cells has properties that scientists believe could make it possible for the protein to fight sepsis. The treatment is still being investigated but laboratory tests have found it effective.

West Nile Virus

West Nile virus is making its return in the warm weather. Rockland County in New York is one of a number of areas over 35 states in which there have been reports of infection or signs that mosquitoes are carrying the disease. As of this week, New York has joined Arizona, California, Colorado, Georgia, Iowa, Louisiana, Mississippi, Missouri, Nebraska, New Mexico, Oklahoma, South Dakota, Tennessee, Texas, and Wisconsin in having reported West Nile virus infections in human beings to the Centers for Disease Control. In 2012, there were 107 cases of West Nile in New York State, and nine resultant deaths. Health officials say the appearance of the virus in Rockland was the first in the state this year.

West Nile virus doesn’t usually affect human beings; other than the mosquitoes that are carriers, birds are the most commonly infected animals. Infection with the virus may not have any symptoms. Only about one in every 150 people to become infected with the virus actually gets sick from it, mostly children and the elderly. When symptoms do appear, they are often mild—headache and skin rash, most commonly. It was strictly a tropical disease until the very end of the 20th century, only coming northward in the 1990s. There were more than 25 times as many cases in the United States in 2002 as in the three previous years combined, and nearly 16 times as many deaths. The good news is that the mortality rate is dropping; only four percent of people who got sick in 2012 died, compared to 15 percent in 2001.

There is no cure for West Nile disease. Preventing it means eliminating the mosquitoes responsible for spreading the disease. On an individual level, window screens and insect repellant are the tools people use, protecting themselves from the insects. Elimination of standing water—birdbaths, tire swings, persistent puddles—denies them a place to gather. In addition, health officials in many places conduct eradication campaigns, eliminating the mosquitoes for good.

Interestingly, while West Nile virus is related to the pathogen responsible for Dengue fever, the same prevention methods don't necessarily work on both. In fact, a mosquito bacteria that blocks transmission of Dengue fever to humans has the exact opposite effect on West Nile virus. In a study, mosquitoes protected against Dengue virus had higher than normal West Nile infection rates, the opposite of what the researchers had expected.

Infected Wounds

Most people are surrounded by germs most of the time. But this isn’t cause for concern—the body is very good at warding off illness. Most of the time, people don’t even notice. However, the first line of defense against infection is the skin, and when that is breached—when a wound or injury happens—the danger increases. When bacteria enters a wound, the immune system normally springs into action. When the immune system is compromised, or even just overwhelmed, however, the result is an infection that can, depending on what and where the infection is, can be anywhere from unpleasant to deadly.

That’s because wound infection can cause sepsis, inflammation over the entire body that results from the immune system kicking into high gear to fight a particularly strong bacterial barrage. However, the inflammation itself can cause organ and tissue damage throughout the body. That is why it is important to take steps to avoid infection. In hospitals—where a "e;wound,"e; often deliberately inflicted in the form of surgery, may be sizable, and the patient’s immune system is likely to be compromised due to illness or aspects of the surgery, steps are taken to avoid sepsis. Wounds in other settings are likely smaller, but in the absence of such precautions as incisions made with careful attention, and in clean rooms, more effort may be needed after the fact.

Cuts and scrapes are common types of injuries—in fact, someone who has a scrape or even a cut may not even notice until it scabs over. Puncture wounds are less common, but not unknown. In either case, it is necessary for the bleeding to be stopped before the wound is cleaned. Bleeding itself is a part of the defense against infection, washing out the initial wave of bacteria. After cleaning the wound, antibiotic cream is applied to get rid of bacteria, and a dressing or bandage provides protection.

Even with precautions such as these taken, infection is still possible. Most infection is minor and passes within a few days, but in some cases people with infected wounds require medical attention. Infection can be spotted under the dressing. Infection is likely present when the wound is red, painful, or swollen, or smells foul. Bleeding after the wound should have scabbed, or pus coming out, may also be an indicator of infection. In addition, a person with an infected would may complain of dizziness, or have a fast heartbeat.

Rotavirus Protection

According to the Centers for Disease Control and Prevention, the biggest single cause of infant diarrhea and dehydration in the world is rotavirus. In fact, experts believe that by the age of five, nearly every child has experienced at least one rotavirus infection. Indeed, the resistance these repeated infections build up is a major part of the reasons adults are so rarely made ill by rotavirus. Unfortunately, not all infected children survive to adulthood; it is estimated that rotavirus gastroenteritis kills 450,000 children each year, typically by dehydration. Rotavirus destroys cells in the digestive system, leading to vomiting and then diarrhea that can last more than a week.

Adult immunity is somewhat a double-edged sword. While adults show no symptoms of the infection, the virus itself remains active, and can by transmitted from person to person as any other infection can. Statistics show sanitation having little effect on the incidence of rotavirus infection. What does help is vaccination. Rotavirus gastroenteritis is asymptomatic in infants younger than two months, and two months of age is when doctors recommend the first dosage of rotavirus vaccine to be given. Needed further doses—up to three all told—are given at two-month intervals subsequently. Pediatricians say rotavirus vaccination saves parents and health care facilities almost $1 billion since 2010.

That, perhaps, is one reason people are trying to make the vaccines easier to get. In New Zealand, a government-sponsored program aims to vaccinate every child born in the country. The goal of the program is to ensure that, by the end of 2014, at least 95 percent of toddlers under eight months in New Zealand have been vaccinated. Reports say that the program is on schedule and children are getting the protection they need.

The vaccine has additional benefit that researchers were not aware of. As well as causing gastroenteritis, rotavirus is associated with some forms of seizure disorder. Vaccinating children against infection, then has the further effect of reducing the risk of seizure-related hospitalization by 20 percent. That translates to preventing 5,000 emergency room visits due to seizure. That alone saves more than $7 million in health care costs. What’s more, researchers now say there are connections between rotavirus and type 1 diabetes. Though susceptibility to type 1 diabetes is hereditary, it requires a trigger to develop. Vaccination means rotavirus is not such a trigger.

Causes Of Ulcers

An ulcer is a sore that develops in the stomach lining or elsewhere in that area of the digestive system. They most often occur in the duodenum, the part of the small intestine near the stomach. Ulcers tend to appear as either craters formed through erosion of the tissue or as abnormal growths of the intestinal wall. Symptoms generally start out relatively mild, as slight discomfort in the stomach. The pain gradually worsens as the ulcer grows, getting both larger and more intense. It will often be worse at night or when the sufferer hasn’t eaten. The pain may go away for a few days or even weeks, only to come right back.

It used to be—and in some circles still is—common knowledge that ulcers were caused by stress. However, while stress can exacerbate flares, the cause is more biological. Ulcers are sometimes caused by certain medications. Aspirin and other painkillers with anti-inflammatory properties can irritate the stomach lining and cause sores to develop.

However, most stomach ulcers are caused by bacteria, most frequently Heliobacter pylori. H. pylori is an infectious bacterium that takes up residence in the stomach linings of those who contract it. It is ordinarily benign, but sometimes it gets out of control, colonizing the gut and leading to ulcers. It isn’t clear why this happens in some cases but not others, but researchers have found that gut microflora, bacteria and other microbes that line the digestive tract and play a role in metabolizing foods, are also responsible for resistance to H. pylori-caused ulcers. In particular, a class of bacteria known as Clostridia seem to create an immune response toH. pylori.

In another study, researchers also found a promising vaccine for H. pylori. This is important because in addition to ulcers, H. pylori has been linked with some kinds of cancer. The bacterium stands down a tumor defense in the gut, allowing stomach cancer to develop. The vaccine, administered orally, would prevent H. pylori from getting a foothold in the patient’s body, preventing ulcers and cancer. It can be given to people who have never been infected and to people who have been treated to prevent relapse.