FUNGAL DISEASES

BY: SAI MANOGNA (MSIWM014)

Introduction:

Fungi: Fungi are eukaryotic microorganisms that do not photosynthesize and have a cellular wall. They parasitize or live as spores of organisms. Fungi invade keratinized tissue such as the horny cell layer, hair, and nails in superficial mycosis. 

1. A broad range of fungi that are commonly present in the environment cause fungal diseases. 

2. These invasive fungal infections occur rarely in healthy people, but in individuals with compromised immune systems, fungi may cause severe infections. 

3. In the soil and on plants and trees, as well as indoor surfaces and human skin, fungi live outdoors. 

4. Millions of different fungi species exist, but it is known that only a fraction of them make people sick. 

5. Anyone may get a fungal infection, such as a toenail infection or an athlete’s foot infection, but individuals with weakened immune systems are more likely to get severe fungal infections. 

6. An increasing danger to human health is fungal diseases. People living with HIV / AIDS, organ or stem cell transplants, cancer patients, and hospitalized patients are vulnerable to infection, while healthy people seldom suffer from severe fungal infections. 

7. Only four antifungal drugs exist, and fungal strains are emerging that are resistant to these drugs. At present, there are no licensed vaccines to prevent fungal infections.

Types of Fungal infections:

Many common fungal infections may infect the skin. Besides the skin, mucous membranes are another common place for fungal infections. Some examples of these are infections of vaginal yeast and oral thrush.

A. Candidiasis:

1. Candida is a yeast that can be found in the digestive tract, on the skin, on mucous membranes. 

2. Overgrowth of these yeasts can cause the development of symptoms that occur in the mouth or throat; for example, it is called “thrush” or candidiasis of the oropharynx. 

3. Usually, candidiasis in the vagina is referred to as a “yeast infection.” Overgrowth of these fungi can cause invasive candidiasis for individuals with certain risk factors, a severe infection that can damage the body’s blood, heart, brain, skin, bones, and other sections. 

4. The most common type of invasive candidiasis is candidemia, a bloodstream infection with Candida, and it often affects hospitalized patients. 

5. More than 20 Candida yeast species can cause human infection, but most infections are caused by Candida albicans, C. glabrata, C. parapsilosis. 

6. Tropicalis, Candida auris is a newly emerging fungi species that are difficult to detect and frequently avoids multiple antifungal drugs.

B. Aspergillosis:

1. A common mold found indoors and outdoors is Aspergillus. 

2. Without being sick, people breathe in various Aspergillus spores every day. 

3. People with compromised immune systems or lung disorders are, however, at risk of developing Aspergillus-induced health problems. 

4. Several kinds of aspergillosis range from mild to extreme illnesses. For instance, without causing infection, Aspergillus may cause inflammation of the lungs (allergic bronchopulmonary aspergillosis) or sinuses (allergic Aspergillus sinusitis). Invasive aspergillosis is a rare, severe lung or other body system infection and is a significant cause of mortality in immunocompromised people.

C. Cryptococcosis:

1. Cryptococcus fungi are present worldwide in the soil and are mostly related to bird droppings. 

2. Two key disease-causing species exist: Cryptococcus neoformans and C. gattii. 

3. These fungi cause infections in healthy individuals, but for people with weakened immune systems, such as those with HIV / AIDS, they can be severe. 

4. The infection happens typically when others inhale the fungus. The lungs and the nervous system are the most common sites of infection. The most prevalent cause of meningitis in adults is cryptococcal meningitis, a leading cause of death in people with HIV / AIDS.

D. Coccidioidomycosis (Valley Fever):

 1. It is an infection caused by the Coccidioides immitis and C posadasii fungi, also referred to as Valley Fever. These are soil-dwelling fungi found in arid, desert-like conditions. 

2. The fungi were discovered recently in south-central Washington. Infection usually happens by breathing Coccidioides spores into the lungs, and healthy individuals are at risk of Coccidioides infection, unlike most severe fungal diseases. 

3. In California and Arizona, the highest rate of infection has taken place. These states registered more than 11,000 Valley Fever cases in 2016 to estimate 15 to 30 percent of community-acquired pneumonia. 

4. Valley Fever can, however, be under-reported due to low testing rates. A self-limiting, moderate, flu-like disease can range from Valley Fever to severe disseminated infection that may require life-long therapy.

E. Athlete’s Foot:

1. Athlete’s foot infection is also called tinea pedis, which occurs on foot.

2. In wet, moist places such as shoes, socks, swimming pools, locker rooms, and public showers, the fungi grow best. 

3. In summer and hot, humid climates, they are always found. 

4. People who wear tight shoes, who do not change their sweaty socks, and use public baths and pools are more likely to do so. 

Causes: The fungi behind the foot of the athlete reside on the dead tissue of hair, toenails, and layers of the outer skin. There are four kinds of fungus which cause the infection. Trichophyton rubrum is the most common. 

Symptoms: The symptoms of an athlete’s foot vary from individual to individual such as, peeling, cracking of feet, blisters, black, softened, or broken-down skin, itching, and burning sensation.

F. Ringworm:

1. This ringworm is not a worm. It is a skin infection caused by moldlike fungi that live on skin, hair, and nails’ dead tissues. 

2. It can also cause infection on the scalp. 

3. That is what people call an athlete’s foot when they have it between the toes and also known as jock itch if it extends to the groin. 

Symptoms: A red, scaly patch or bump that itches is the telltale sign. The bump transforms into a ring- or circle-shaped patch over time. Maybe it will transform into many circles. Usually, the interior of the patch is transparent or scaly. The outside could be elevated and bumpy slightly. Ringworm appears to start as a lump or slight sore on the scalp. It may be flaky and scaly, and the contact may feel tender and painful on the scalp. It may also be noted that patches of hair are starting to fall out. 

Causes: The ringworm is incredibly infectious. In any of the following forms, can capture it by: 

From a different person: often, ringworm spreads by skin-to-skin touch. 

From the dogs: By rubbing sparky or grooming her, when it is done, the face should be washed. It is prevalent for cows, too. 

By touching things: On surfaces, clothing, towels, and in combs and brushes, the fungus that causes ringworm can linger. 

From the dirt: If people work or stand barefoot in soil tainted with the ringworm-causing fungus, they might get it.

G. Jock Itch:

1. Jock itch is caused by a form of fungus called Tinea. Often known as tinea cruris, the infection is Tinea is fond of wet, damp areas such as the groin, inner thighs, and buttocks. 

2. More commonly, infections occur in the summer or humid, wet climates. 

3. Jock itch is a red, itchy, frequently ring-shaped rash. 

Causes: jock itch is a mildly infectious, which spreads from person to person by direct or indirect contact through objects with the fungus on them. 

Symptoms: Jock itch signs include; On the groin or thigh, scratching, chafing, or burning, a circular, red rash with raised edges, redness in the thigh or groin, skin that flakes, peels, or cracks.

FOOD SPOILAGE

BY:- RAHUL ANDHARIA (MSIWM001)

Food Spoilage:

It refers to change in Physical and Chemical property of food, making food unfit for Consumption. Invasion of microorganisms like bacteria and fungi usually causes spoilage of food.

Principle:

Food spoilage generally occurs due to Physical, Chemical or Biological agents that changes colour, flavour, appearance, odour and other properties of food. Shelf life of most of the natural foods is very less and is perishable, for example, meat, fish and bread can spoil easily. Decomposition of food generally involves 3 processes: Putrefaction (chemical breakdown of food or decay of organic matter), Fermentation (chemical breakdown of substances by action of microorganisms, yeast), Rancidity ( refers to oxidation of fats).

Natural Contamination:

It refers to contamination of food when microorganisms themselves attaches to food in its growing stages and this kind of contact is essential for certain kinds of food. For example, Yeasts contaminates fruit for carbohydrates fermentation.

Artificial Contamination:

This type of contamination occurs during handling of food when food is under various stages of production like, packaging, storage, etc. Improper handling of food during this stages results in contamination of food by microorganisms.

Intrinsic factors of food like pH, redox potential, H2o activity determines the type of microflora growing on the food. This final composition of microflora is responsible for food spoilage.

Types of Food Spoilage:

1.Microbial Spoilage:

Microorganisms associated with food are:

Bacteria, Filamentous Fungi, Viruses, Yeasts, and animal parasites.

Bacteria:

They are associated with both plant and animal foods. Bacteria are associated with food intoxication and spreading of food borne diseases.

Examples:

Acenatobacter:  Gram negative- present in raw and prepared foods like beef and poultry carcasses.

Aero monas: gram negative, responsible for spoilage of fish.

Alkaligans: gram negative, responsible for spoilage of egg and dairy products.

Citrobacter: gram negative, it is responsible for spoilage of vegetables and fresh meat.

Corynebacterium: gram positive, involved in spoilage of vegetables and  meat.

Filamentous Fungi:

When food is left for one or more day covered, tangled mass of furry growth appears on food which is called fungi or mould. Fungi are responsible for spoilage of Grains, nuts, and fruits as they have low pH and H20 activity.

Examples:

Mucor: Zygomycotena-common contaminant of fruits, berries and nuts.

Rhizopus: Zygomycotena- known commonly as bread mould. It is more prevalent in fermented and stored foods.

Claviceps: Ascomycotena-  produces toxic alkaloids in cereals, when consumed can cause Hallucinations.

Yeasts:

Contamination by yeasts results in Souring of milk.

Examples:

Candida: most common contaminant of dairy products, fresh fruits, and alcoholic beverages.

Saccharomyces: spoilage of fruits and fruit products.

Torulopsis: responsible for spoilage of beef, creamed butter, condensed milk, etc.

Viruses:

viruses found in food are termed as enteric or intrinsic viruses.

Examples:

Enterovirus, Adenovirus, Reovirus, Hepatitis A virus.

Animal Parasites:

They belong to 3 distinct groups:

Protozoa: Giardia, Entamoeba Hystolytica

Flatworms: Taenia, Fasciola

Roundworms: Ascaris

2. Physical Spoilage:

Physical Spoilage refers to damaging of food during Harvesting, Processing or distribution of food. During such processes there are high chances of food spoilage if proper measures are not followed. The damage increases the chance of spoilage as the outer layer is completely broken or bruised. For example- Canned foods gets spoiler easily if the cans are not properly packed with lid or are contaminated during processing.

3. Chemical Spoilage:

Chemical reactions in food are responsible for change of colour, texture and taste of the food products. Generally foods are fresh especially vegetables and animal food, but after harvesting and slaughtering, chemical changes begin automatically in the food and the quality of food becomes deteriorated.

4. Enzymic Spoilage:

Enzymes acts as biological catalyst to carry out biological reactions in cell and play an important role in biochemical reactions. After death of cells or tissues, enzymes play a role in its decomposition by a process called Autolysis( self destruction )

Example: In tomatoes, some enzymes helps it for ripening, but at the same time there are certain enzymes which are responsible for its decay. Once enzymic Spoilage is underway, it damages the outer skin of tomato and exposes it to mould growth and decay.

Factors Affecting Food Spoilage:

  1. Water Content: Amount of water holding capacity in foods is referred to as it’s water activity.(WA). Water activity of most of the fresh fruits is approximately 0.99, which makes them more susceptible to microbial growth.
  2. Environmental Conditions: Environmental influence on food is the major concern. When food is exposed to intrinsic conditions like temperature, air, or even small amount of moisture, can result in growth of Micro-organisms. Changing environmental conditions can help to prevent spoilage. For example- storing food at lower temperature can prevent it from spoiling.
  • Packaging and storage: Packaging of foods is after processing is very vital as it protects food from harmful contaminants and also from various other factors like environment, temperature, etc. The type of packaging plays a key factor in ensuring the safety and preventing spoilage. Food packed in jars, cans ensures safety and prevents food from dust, moisture, air and harmful microbes.

Sources of Micro-organisms for Food Spoilage:

Micro-organisms are present everywhere. General source of Micro-organisms include air, water, sewage, soil and animal wastes. Foods grown in ground have higher risk of spoilage due to micro-organisms.  Foods like fish, meat are contaminated by presence of bacteria in their  internal organs like skin and feet. Meat has higher tendency of contamination as raw meat attracts lot of microbes, so it is advisable to store raw meet immediately after chopping.

Ways to Prevent Food Spoilage:

  • Ensure proper packaging is available to the food cans and jars after processing.
  •  Don’t leave the food in open air for more than 15min, to avoid contact with microbes.
  •  Ensure that your refrigerators are operating at correct temperatures.
  •  Food must be protected from light and must be stored in amber colour or transparent containers.
  • Low temperature is a key as it retards microbial growth.
  • Avoid placing food where there is more humidity, as high humidity attracts more growths of microbes and moulds. Placing food in dry places is most appropriate.