Wheat yellow rust ("Puccinia striiformis" f.sp. "tritici"), also known as stripe rust, is one of the three wheat rust diseases principally found in wheat grown in cooler environments. Such locations are generally associated with northern latitudes or cooler seasons.

As R.P. Singh, J. Huerta-Espino, and A.P. Roelfs say in their (undated) comprehensive review of literature on the wheat rusts for UN FAO:

"Although Gadd first described stripe rust of wheat in 1777, it was not until 1896 that Eriksson and Henning (1896) showed that stripe rust resulted from a separate pathogen, which they named P. glumarum. In 1953, Hylander et al. (1953) revived the name P. striiformis."

Leaf rust is a fungal disease of barley caused by "Puccinia hordei". It is also known as brown rust and it is the most important rust disease on barley.

Cyclaneusma (needle cast) is a fungal disease that is a part of the phylum, Ascomycota. It infects plants that are of pine classification. After infection by "Cyclaneusma", most pines do not display symptoms until 10 months after the initial infection. Symptoms include needles developing yellow spots, horizontal brown bands around the needles, swelling of needles, and off-white fruiting bodies formed on infected needles. Because "Cyclaneusma" is an ascomycete it produces two spore types, an asexual (conidiomata) and sexual (ascomycota) spore. Controlling "Cyclaneusma" has presented a challenge as the disease can survive on both living and dead needles during the winter months. Effective management methods include planting new pines in non-shaded, well drainable soil as well as spraying fungicide. "Cyclaneusma" Needle Cast is an important fungal disease because it directly impacts the commercial value of decorative pines as well as lumber.

Pustules of leaf rust are small and circular, producing a mass of orange-brown powdery spores. They appear on the leaf sheaths and predominantly on the upper leaf surfaces. Heavily infected leaves die prematurely.

The foamy bark canker is a disease affecting oak trees in California caused by the fungus "Geosmithia pallida" and spread by the Western oak bark beetle ("Pseudopityopthorus pubipennis"). This disease is only seen through the symbiosis of the bark beetles and the fungal pathogen. The bark beetles target oak trees and bore holes through the peridermal tissues, making tunnels within the phloem. The fungal spores are brought into these tunnels by the beetles and begin to colonize the damaged cells inside the tunnels. Symptoms of the developing fungus include wet discoloration seeping from the beetle entry holes as the fungus begins to consume phloem and likely other tissues. If bark is removed, necrosis of the phloem can be observed surrounding the entry hole(s). As the disease progresses, a reddish sap and foamy liquid oozes from entry holes, thus giving the disease the name Foamy bark canker. Eventually after the disease has progressed, the tree dies. This disease is important because of its detrimental effects on oak trees and its ability to spread to several new Californian counties in just a couple years.

Velvet disease (also called gold-dust, rust and coral disease) is a fish disease caused by dinoflagellate parasites of the genus "Piscinoodinium", specifically "Amyloodinium" in marine fish, and "Oodinium" in freshwater fish. The disease gives infected organisms a dusty, brownish-gold color. The disease occurs most commonly in tropical fish, and to a lesser extent, marine aquaria.

Hosts associated with "Geosmithia pallida" include a number of tree species, including oak and other hardwoods, pine and spruce trees, depending on the beetle vector. In this case, the western oak bark beetles target live oak trees of western United States. Beetles tend to attack stressed trees that are already weakened from drought or injury. Symptoms causing branch dieback and tree death also include a cinnamon-colored gum seeping from multiple beetle entry holes on the bole, followed by a prolific, cream-colored foamy liquid. These symptoms, as well as signs (entry holes, larvae, beetles) of bark beetles, are key factors in diagnosis. Necrosis of xylem and phloem tissues underneath bark can be observed.

Common Symptoms:

- Wet discoloration on bark

- Phloem necrosis

- Beetle entry holes

- Reddish sap oozing from entry holes

- Foamy liquid from entry holes

The single-celled parasite's life cycle can be divided into three major phases. First, as a tomont, the parasite rests at the water's floor and divides into as many as 256 tomites. Second, these juvenile, motile tomites swim about in search of a fish host, meanwhile using photosynthesis to grow, and to fuel their search. Finally, the adolescent tomite finds and enters the slime coat of a host fish, dissolving and consuming the host's cells, and needing only three days to reach full maturity before detaching to become a tomont once more.

Needle cast diseases in general are somewhat difficult to diagnose simply because their symptoms are similar to low pH, poor nutrition, fertilizer or chemical burn, and even root rots. Correct diagnosis requires microscopic examination of the size and shape of the fungal producing ascospores. Unfortunately these fungal spores are produced quite infrequently; after the disease infects needles, it will not produce symptoms or additional spores until the following year. In addition, "Cyclaneusma" may not be the only fungus present on the diseased needles. Saprophytic fungi live on dead tissue and may therefore continue to worsen the infection on needles after they have fallen. Saprophytes will also be present if the needles were killed by fertilizer burn or root rots. Due to these obstacles, it is important to examine the spores directly after infection (while spores are being produced) in order to ensure that "Cyclaneusma" is indeed the pine’s cause of death.

The lesions are most frequent on the lower limbs, but may occur anywhere on the body, including the hands, arms, torso and even the neck. They may vary in number and erupt in mass numbers.

They consist of irregular patches of orange or brown pigmentation with characteristic "cayenne pepper" spots appearing within and at the edge of old lesions.

There are usually no symptoms, although there may be some slight itching, but there is no pain.

The eruption may persist for many years. The pattern of the eruption changes, with slow extension and often some clearing of the original lesions.

Schamberg's disease, or progressive pigmented purpuric dermatitis, is a chronic discoloration of the skin which usually affects the legs and often spreads slowly. This disease is more common in males and may occur at any age from childhood onward. This condition is observed worldwide and has nothing to do with race or ethnic background.

Whilst witnessing procedures involving needles it is possible for the phobic present to suffer the symptoms of a needle phobic attack without actually being injected. Prompted by the sight of the injection the phobic may exhibit the normal symptoms of vasovagal syncope and fainting or collapse is common. While the cause of this is not known, it may be due to the phobic imagining the procedure being performed on themselves. Recent neuroscience research shows that feeling a pin prick sensation and watching someone else's hand get pricked by a pin activate the same part of the brain.

Hyperalgesic fear of needles is another form that does not have as much to do with fear of the actual needle. Patients with this form have an inherited hypersensitivity to pain, or hyperalgesia. To them, the pain of an injection is unbearably great and many cannot understand how anyone can tolerate such procedures.

This form of fear of needles affects around 10% of needle phobes. The symptoms include extreme explained anxiety, and elevated blood pressure and heart rate at the immediate point of needle penetration or seconds before. The recommended forms of treatment include some form of anesthesia, either topical or general.

Soot tattoos are a cutaneous condition that may be a sign of drug abuse, a condition produced by injections of residual carbon on the needle after flaming of the tip.

Soot tattoos are considered the oldest form of tattoos. The 5300 year old body of Tyrolean iceman Ötzi is decorated with simple tattoos, and researchers think they may have served a medicinal purpose, not a decorative one.

Soot tattoos are still used in some countries.

Schamberg's disease, (also known as "progressive pigmentary dermatosis of Schamberg", "purpura pigmentosa progressiva" (PPP), and "Schamberg's purpura") is a chronic discoloration of the skin found in people of all ages, usually affecting the legs. It slowly spreads throughout the body, and is most common in males. It is named after Jay Frank Schamberg, who described it in 1901. There is no known cure for this disease and it is not a life-threatening condition. The skin lesions may cause itching, which can be treated by applying cortisone cream. The cortisone cream will only help with the itching and the discoloration of the skin will remain, which may cause a cosmetic concern in the future. Schamberg's disease is usually asymptomatic meaning that it shows no signs of this condition, except for the discoloration of the skin. This condition is caused by leaky blood vessels, where red blood cells escape near the surface of skin and release its iron into the surrounding tissue. The cause of the leaky capillaries is unknown.

Aichmophobia () is a kind of specific phobia, the morbid fear of sharp things, such as pencils, needles, knives, a pointing finger, or even the sharp end of an umbrella and different sorts of protruding corners or sharp edges in furnitures and building constructions/materials. It is derived from the Greek "aichmē" (point) and "phobos" (fear). This fear may also be referred to as belonephobia or enetophobia.

Sometimes this general term is used to refer to what is more specifically called fear of needles, or needle phobia. Fear of needles is the extreme and irrational fear of medical procedures involving injections or hypodermic needles.

Not to be confused with similar condition (Avoidance behavior) the Visual looming syndrome, where the patient does not fear sharp items, but feels pain or discomfort at gazing upon sharp objects nearby.

A contagious disease is a subset category of transmissible diseases, which are transmitted to other persons, either by physical contact with the person suffering the disease, or by casual contact with their secretions or objects touched by them or airborne route among other routes.

Non-contagious infections, by contrast, usually require a special mode of transmission between persons or hosts. These include need for intermediate vector species (mosquitoes that carry malaria) or by non-casual transfer of bodily fluid (such as transfusions, needle sharing or sexual contact).

The boundary between contagious and non-contagious infectious diseases is not perfectly drawn, as illustrated classically by tuberculosis, which is clearly transmissible from person to person, but was not classically considered a contagious disease. In the present day, most sexually transmitted diseases are considered contagious, but only some of them are subject to medical isolation.

The photic sneeze reflex (also known as photoptarmosis, Autosomal Dominant Compelling Helio-Ophthalmic Outburst Syndrome (ACHOO) and colloquially sun sneezing) is a condition that causes sneezing in response to numerous stimuli, such as looking at bright lights or periocular (surrounding the eyeball) injection. The condition affects 18-35% of the population in the United States, but its exact mechanism of action is not well understood.

A needlestick injury, percutaneous injury, or percutaneous exposure incident is the penetration of skin by a needle or other sharp object, which was in contact with blood, tissue, or other body fluid before the exposure. Occupational needlestick injuries primarily affect healthcare workers, who make up 80% of needlestick injuries in the United States. Various other occupations are also at increased risk of needlestick injury, including law enforcement, laborers, tattoo artists, food preparers, and agricultural workers. Though the acute physiological effects of a needlestick injury are generally negligible, these devices can transmit blood-borne diseases, placing those exposed at increased risk of contracting infectious diseases, such as hepatitis B (HBV), hepatitis C (HCV), and the human immunodeficiency virus (HIV). Among healthcare workers and laboratory personnel worldwide, more than 25 blood-borne viruses have been reported to be caused by needlestick injuries.

It is estimated that half of all occupational needlestick injuries are not reported. Additionally, an unknown number of occupational needlestick injuries are reported by the affected employee, yet due to organizational failure, institutional record of the injury does not exist. Increasing recognition of the unique occupational hazard posed by needlestick injuries, as well as the development of efficacious interventions to minimize the largely preventable occupational risk, encouraged legislative regulation in the US, causing a decline in needlestick injuries among healthcare workers.

A bloodborne disease is a disease that can be spread through contamination by blood and other body fluids. Bloodborne pathogens are microorganisms such as viruses or bacteria. The most common examples are HIV, hepatitis B and viral hemorrhagic fevers.

Diseases that are not usually transmitted directly by blood contact, but rather by insect or other vector, are more usefully classified as "vector-borne disease", even though the causative agent can be found in blood. Vector-borne diseases include West Nile virus and malaria.

Many bloodborne diseases can also be contracted by other means, including high-risk sexual behavior or intravenous drug use. These diseases have also been identified in sports medicine.

Since it is difficult to determine what pathogens any given sample of blood contains, and some bloodborne diseases are lethal, standard medical practice regards all blood (and any body fluid) as potentially infectious. "Blood and Body Fluid precautions" are a type of infection control practice that seeks to minimize this sort of disease transmission.

When triggered, most people with a specific phobia experience an increase in blood pressure and an extreme amount of anxiety; however, an individual who has BII phobia experiences something different: first, the person’s blood pressure increases and then swiftly decreases the next moment. During this rapid change in blood pressure, a period of a vasovagal response occurs, which causes less blood and oxygen to be sent to the brain, resulting in loss of consciousness momentarily. The heart rate then slows down, due to the activation of the parasympathetic nervous system. The parasympathetic activation is believed to be associated with the disgust response, which is a characteristic of BII phobia, making it stand out from other phobias. Other symptoms can include extreme discomfort in the chest and tunnel vision.

Moreover, FMRI studies have confirmed that the activation level of the prefrontal cortex, which is responsible for controlling and regulating emotions, is lower in people with this type of phobia when exposed to a fear-inducing stimuli. This shows that people with BII phobia have less control over their emotions because of the lessened activity in their prefrontal cortex. This lessened emotional control could contribute to the high disgust reaction as well as less control over phobic symptoms, such as fainting.

Abscesses may occur in any kind of solid tissue but most frequently on skin surface (where they may be superficial pustules (boils) or deep skin abscesses), in the lungs, brain, teeth, kidneys, and tonsils. Major complications are spreading of the abscess material to adjacent or remote tissues, and extensive regional tissue death (gangrene).

The main symptoms and signs of a skin abscess are redness, heat, swelling, pain, and loss of function. There may also be high temperature (fever) and chills.

An internal abscess is more difficult to identify, but signs include pain in the affected area, a high temperature, and generally feeling unwell.

Internal abscesses rarely heal themselves, so prompt medical attention is indicated if such an abscess is suspected.

An abscess could potentially be fatal (although this is rare) if it compresses vital structures such as the trachea in the context of a deep neck abscess.

If superficial, abscesses may be fluctuant when palpated. This is a wave-like motion that is caused by movement of the pus inside the abscess.

Tetanus often begins with mild spasms in the jaw muscles—also known as lockjaw or trismus. The spasms can also affect the facial muscles resulting in an appearance called risus sardonicus. Chest, neck, back, abdominal muscles, and buttocks may be affected. Back muscle spasms often cause arching, called opisthotonos. Sometimes the spasms affect muscles that help with breathing, which can lead to breathing problems.

Prolonged muscular action causes sudden, powerful, and painful contractions of muscle groups, which is called "tetany". These episodes can cause fractures and muscle tears. Other symptoms include drooling, excessive sweating, fever, hand or foot spasms, irritability, difficulty swallowing, suffocation, heart attack, breathing problems, irregular heartbeat, and uncontrolled urination or defecation.

Even with treatment, about 10% of people who contract tetanus die. The mortality rate is higher in unvaccinated people and people over 60 years of age.

BII phobia tends to have an affect on people's health, since the individuals with this phobia, usually avoid needles, vaccinations, and blood tests, making them susceptible to diseases and other health-related issues. Women, in particular, suffering from BII phobia, reported to have avoided pregnancy in fear of injections, vaccinations, and the pain associated with labor. BII phobia patients suffering from diabetes or multiple sclerosis are often unable to get injections and are thus more likely to discontinue their treatment.