Category: Medicine Hat News

Dear Dr. B: What is a fungus? What are the common fungi which cause illnesses in humans?

Answer: The American Heritage Science Dictionary defines fungi as any of a wide variety of organisms that reproduce by spores, including the mushrooms, moulds, yeasts, and mildews. Spores can remain dormant for years. Some of the characteristics of fungi are:
-fungi absorb food by excreting enzymes that break down complex substances into molecules that can be absorbed into the hyphae
-the spores of most fungi grow a network of slender tubes called hyphae that spread into and feed off of dead organic matter or living organisms
-fungi can live in a wide variety of environments, fungal spores can survive extreme temperatures and fungi exist in over 100,000 species, nearly all of which live on land
-they can be extremely destructive, feeding on almost any kind of material and causing food spoilage and many plant diseases
-although fungi were once grouped with plants, they are now considered a separate kingdom.

Fungi are all around us. The fungus grows best in moist, damp, dark places with poor ventilation and on skin that is irritated, weakened, or continuously moist. Most of the fungi are very helpful in the natural environment and only a few cause diseases in humans, plants and animals.

Candida is yeast like fungus which may cause athlete’s foot, vaginitis, thrush, or other infections. It can thrive in moist skin fold areas under the breasts, overhanging abdominal adipose tissues, groins, between fingers and toes, in the armpits and in the anus. Some of the fungi are dermatophytes which cause parasitic infections of the skin, hair, nails and adjacent mucous membranes.

Systemic fungal infections occur when spores are touched or inhaled, or there is an overgrowth of fungi in or on the body. Such infections are most often in people taking antibiotics which kill off the bacteria that normally keep fungi at bay. This is also the case in people with endocrine disorders, immune diseases, and other conditions such as obesity, AIDS, tuberculosis, major burns, leukemia, and diabetes mellitus. Patients with systemic infection may have no symptoms or may have flu-like symptoms – coughing, fever, chest pain, chills, weight loss, and difficulty with breathing.

Certain fungi, such as mushrooms, can produce poisonous toxins that may prove fatal if ingested. Certain moulds can be highly toxic to humans. A condition called egotism is caused by eating bread prepared from rye infected with the fungus.

Moulds are often found spreading over bread, cheese, books, and other things in the home and may be a menace to our health. Painted walls, particularly in humid places such as showers, can become overgrown by certain fungi. Certain types of wallpapers also serve as a source of nutrition for some moulds and may prove to be harmful. Virtually all buildings contain moulds depending on the amount of moisture present in the building. Moulds can cause headache, nausea or respiratory symptoms amongst the occupants of the building.

Skin infection with fungus can be treated with antifungal skin ointment. Systemic fungal infection requires oral antifungal pills. Fungal infection can be prevented by keeping our body and the environment clean and healthy.

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Dear Dr. B: What is a bacterium? What are the common bacteria which cause illnesses in humans?

Answer: A bacterium (bacteria is the plural of bacterium) is a very small, single-celled microorganism that can reproduce rapidly. A bacterium has no nucleus. Bacteria come in many shapes including spheres, rods and spirals. They are the most abundant living organisms on earth, and are found in all living things and in all of the earth’s environments.

Bacteria usually live off other organisms. A bacterium is a completely self-contained and self-reproducing unit. A virus, on the other hand, cannot reproduce without a living host.

Most bacteria are considered harmless. Many are beneficial to humans. A small percentage of bacteria, which are harmful, feed on the tissues of the human body and excrete toxins and acids afterwards which causes bacterial infection. Most viruses, on the other hand, serve no beneficial purpose. Their mission in life is to create more viruses in order to assure survival of the strain

Here are some examples of common illnesses caused by bacteria.

The most important human pathogens among the Gram-positive cocci are Staphylococcus aureus which causes skin and soft tissue infections and toxic shock syndrome. Pharyngitis is caused by Streptococcus pyogenes, neonatal meningitis is caused by Streptococcus agalactiae, pneumonia is caused by Streptococci pneumoniae and Enterococcus faecalis causes urinary tract infection.

Meningitis and gonorrhea is caused by the Gram-negative cocci called Neisseria. Gram-positive bacilli cause meningitis, pneumonia, soft tissue infections, brain abscess and diphtheria. There are many other groups of bacteria including the Gram-negative bacilli, the Enterobacteriaceae and others which cause variety of illnesses in humans.

The dawn of bacteriology started with Louis Pasteur (1822-1895). He was interested in the process of fermentation. He proved that fermentation was caused by bacteria or fungi. According to Illustrated History of Surgery, Pasteur studied fermentation of wine and beer and invented the process of pasteurization, which became very important in the dairy industry. He also found a vaccine against anthrax (an illness caused by bacteria).

Pasteur was not a doctor. He was a chemist and became professor of chemistry at the Sorborne in Paris. He also discovered bacteria called staphylococci and streptococci and explained their toxic effects. Pasteur also produced a vaccine against rabies (a viral disease), at that time thought to be incurable disease.

Robert Koch (1843-1910) along with Pasteur is credited with launching the first “golden age” of bacteriology. Koch was one of the first professors of hygiene and bacteriology in Berlin. Koch had developed an apparatus for keeping bacteria alive under the microscope. He discovered the bacteria which causes tuberculosis and cholera. Koch won the Nobel Prize in 1905.

Diseases caused by bacteria are many. We continue to fight the battle against the continuous onslaught from bacteria by developing different varieties of vaccines, medications and antibiotics. But bacteria have ability to change in order to survive treatment. This is called antibiotic resistance and this phenomenon is a growing concern among the health care providers. Overuse and inappropriate use of antibiotics result in bacteria developing resistance.

Our battle against bacteria will never be over. Just like viruses, they keep one step ahead of the game. We should continue to be vigilant in washing our hands and keeping our bodies and environment clean and healthy.

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Dear Dr. B: What is a virus? What are the common viruses which cause illnesses in humans?

Answer: A virus is a minute organism that consists of a core of nucleic acid surrounded by protein. Viruses can grow and reproduce only inside living cells such as bacteria, plants and animals. They are composed of RNA or DNA. Viruses are very small. A special kind of microscope is required to see them.

There are many, perhaps hundreds of different viruses causing all kinds of diseases in animals and plants. Some examples of common human diseases caused by viruses are: AIDS, measles, mumps, smallpox, yellow fever, rabies, poliomyelitis, influenza, the common cold, hepatitis and certain types of cancers. Viruses also cause gastroenteritis.

In the last few months many institutions have fallen victim to viral gastroenteritis, also known as “stomach flu,” although influenza virus has nothing to do with gastroenteritis. Getting a flu shot will not prevent viral gastroenteritis. Many different viruses can cause gastroenteritis, including rotaviruses, adenoviruses, caliciviruses, astroviruses, Norwalk virus and a group of Norwalk-like viruses, now known as noroviruses.

The main symptoms of viral gastroenteritis are watery diarrhea and vomiting. The affected person may also have headache, fever and abdominal cramps (stomachache). In general, the symptoms begin one to two days following infection with a virus that causes gastroenteritis and may last for one to 10 days, depending on which virus causes the illness.

Normally the prognosis is good. Most people recover completely without any long-term effects. But in children and old patients the disease can be fatal if fluid and electrolyte balance of the body is not maintained.

Viral gastroenteritis is contagious. The virus spreads through close contact with infected persons by sharing food and water. Food may be contaminated by people who cook or handle food who have viral gastroenteritis, especially if they do not wash their hands regularly after using the bathroom or changing diapers.

Viral gastroenteritis can affect people in all parts of the world. Some viruses have seasonal activity and occur during cooler months of October to April. Quite often the outbreaks occur in institutional settings such as schools, hospitals and nursing homes and group settings such as cruise ships. Transmission of Norwalk virus is through the fecal-oral route.

Studies have shown water is the most common source of outbreaks. Shellfish and salad ingredients are the foods most often implicated in Norwalk outbreaks. Ingestion of raw or insufficiently steamed clams and oysters poses a high risk for infection with Norwalk virus. Rotavirus and the Norwalk family of viruses are the leading causes of viral gastroenteritis.

Wash your hands, clean and cook your food well and maintain good hygiene. That’s the best way to prevent gastroenteritis. If you like to eat out then pick your restaurants carefully.

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