Since its first description in the 1960s, only seven people worldwide have been reported to have survived PAM as of 2015, with three in the United States and one in Mexico; one of the US survivors had brain damage that is probably permanent. Less than 1% of people with naegleriasis survive.

The disease is rare and highly lethal: there have only been 300 cases as of 2008. Drug treatment research at Aga Khan University in Pakistan has shown that "in-vitro" drug susceptibility tests with some FDA approved drugs used for non-infectious diseases have proved to kill "Naegleria" "fowleri" with an amoebicidal rate greater than 95%. The same source has also proposed a device for drug delivery via the transcranial route to the brain.

The number of cases of infection could increase due to climate change, and was posited as the reason for 3 cases in Minnesota in 2010, 2012, and 2015. In 2016, an infection was contracted in Maryland, four miles south of the Pennsylvania border;

As of 2013, numbers of reported cases were expected to increase, simply because of better informed diagnoses being made both in ongoing cases and in autopsy findings.

There are many different forms on prevention of syphilis and other sexually transmitted diseases in general. Prevention of syphilis includes avoiding contact of bodily fluids with an infected person. This can be particularly difficult because syphilis is usually transmitted by people who are unaware that they have the disease because they do not have any visible sores or rashes that may denote having an infection in general. Being abstinent or having mutually monogamous sex with a person who is uninfected with any type of sexually transmitted disease is the greatest guarantee of not becoming infected with syphilis or any form of a sexually transmitted disease. Using latex condoms can however reduce the risk of obtaining syphilis. In order to prevent further contamination to other individuals, benzathine penicillin is given to any contacts. Washing, douching, or urinating cannot prevent the transmission of a sexually transmitted disease in general.

Individuals obtain syphilis through a variety of circumstances. In general, syphilis can be transmitted from individual to individual through direct contact with sores that are present on the external genitals, vagina, rectum, anus, lips, or mouth. Transmission can occur through any form of sexual contact, including vaginal, anal, and oral sex. In addition, women who are pregnant and infected with syphilis can transmit the disease onto their child as well. If transmission has occurred, it is important to check up immediately with a physician to avoid further damage.

Most household disinfectants will inactivate FHV-1. The virus can survive up to 18 hours in a damp environment, but less in a dry environment and only shortly as an aerosol.

There is a vaccine for FHV-1 available (ATCvet code: , plus various combination vaccines), but although it limits or weakens the severity of the disease and may reduce viral shedding, it does not prevent infection with FVR. Studies have shown a duration of immunity of this vaccine to be at least three years. The use of serology to demonstrate circulating antibodies to FHV-1 has been shown to have a positive predictive value for indicating protection from this disease.

The Jarisch-Herxheimer reaction, which is the response to the body after endotoxins are released by the death of harmful organisms in the human body, starts usually during the first day of antibiotic treatment. The reaction increases the person's body temperature, decreases the overall blood pressure (both systolic and diastolic levels), and results in leukopenia and rigors in the body. This reaction can occur during any treatment of spirochete diseases.

It is important to realize that syphilis can recur. An individual who has had the disease once, even if it has been treated, does not prevent the person from experiencing recurrence of syphilis. Individuals can be re-infected, and because syphilis sores can be hidden, it may not be obvious that the individual is infected with syphilis. In these cases, it is vital to become tested and treated immediately to reduce spread of the infection.

Diagnosis is made with isolation of "Pasteurella multocida" in a normally sterile site (blood, pus, or cerebrospinal fluid).

As the infection is usually transmitted into humans through animal bites, antibiotics usually treat the infection, but medical attention should be sought if the wound is severely swelling. Pasteurellosis is usually treated with high-dose penicillin if severe. Either tetracycline or chloramphenicol provides an alternative in beta-lactam-intolerant patients. However, it is most important to treat the wound.

The cause of immunodeficiency varies depending on the nature of the disorder. The cause can be either genetic or acquired by malnutrition and poor sanitary conditions. Only for some genetic causes, the exact genes are known. Although there is no true discrimination to who this disease affects, the genes are passed from mother to child, and on occasion from father to child. Women tend not to show symptoms due to their second X chromosome not having the mutation while man are symptomatic, due to having one X chromosome.

Gram-negative toe web infection is a relatively common infection. It is commonly found on people who are engaged in athletic activities while wearing closed-toe or tight fitting shoes. It grows in a moist environment. Gram-negative is mixed bacterial infection with the following organisms:

- Moraxella

- Alcaligenes

- Acinetobacter

- Pseudomonas

- Proteus

- Erwinia

This mixing of infection and organisms may also cause a mild secondary infection of tinea pedis.

Viremia (UK: viraemia) is a medical condition where viruses enter the bloodstream and hence have access to the rest of the body. It is similar to "bacteremia", a condition where bacteria enter the bloodstream. The name comes from combining the word virus with the Greek word for blood ("haima"). It usually lasts for 4 to 5 days in the primary condition.

The duration of the visible blistering caused by varicella zoster virus varies in children usually from 4 to 7 days, and the appearance of new blisters begins to subside after the fifth day. Chickenpox infection is milder in young children, and symptomatic treatment, with sodium bicarbonate baths or antihistamine medication may ease itching. It is recommended to keep new infants from birth up to age 6 months away from an infected person for 10 to 21 days because their immune systems are not developed enough to handle the stress it can bring on. Paracetamol (acetaminophen) is widely used to reduce fever. Aspirin, or products containing aspirin, should not be given to children with chickenpox, as it can cause Reye's Syndrome.

In adults, the disease is more severe, though the incidence is much less common. Infection in adults is associated with greater morbidity and mortality due to pneumonia (either direct viral pneumonia or secondary bacterial pneumonia), bronchitis (either viral bronchitis or secondary bacterial bronchitis), hepatitis, and encephalitis. In particular, up to 10% of pregnant women with chickenpox develop pneumonia, the severity of which increases with onset later in gestation. In England and Wales, 75% of deaths due to chickenpox are in adults. Inflammation of the brain, or encephalitis, can occur in immunocompromised individuals, although the risk is higher with herpes zoster. Necrotizing fasciitis is also a rare complication.

Varicella can be lethal to adults with impaired immunity. The number of people in this high-risk group has increased, due to the HIV epidemic and the increased use of immunosuppressive therapies. Varicella is a particular problem in hospitals, when there are patients with immune systems weakened by drugs (e.g., high-dose steroids) or HIV.

Secondary bacterial infection of skin lesions, manifesting as impetigo, cellulitis, and erysipelas, is the most common complication in healthy children. Disseminated primary varicella infection usually seen in the immunocompromised may have high morbidity. Ninety percent of cases of varicella pneumonia occur in the adult population. Rarer complications of disseminated chickenpox include myocarditis, hepatitis, and glomerulonephritis.

Hemorrhagic complications are more common in the immunocompromised or immunosuppressed populations, although healthy children and adults have been affected. Five major clinical syndromes have been described: febrile purpura, malignant chickenpox with purpura, postinfectious purpura, purpura fulminans, and anaphylactoid purpura. These syndromes have variable courses, with febrile purpura being the most benign of the syndromes and having an uncomplicated outcome. In contrast, malignant chickenpox with purpura is a grave clinical condition that has a mortality rate of greater than 70%. The cause of these hemorrhagic chickenpox syndromes is not known.

No preventive measure is known aside from avoiding the traumatic inoculation of fungi. At least one study found a correlation between walking barefoot in endemic areas and occurrence of chromoblastomycosis on the foot.

Prognosis depends greatly on the nature and severity of the condition. Some deficiencies cause early mortality (before age one), others with or even without treatment are lifelong conditions that cause little mortality or morbidity. Newer stem cell transplant technologies may lead to gene based treatments of

debilitating and fatal genetic immune deficiencies. Prognosis of acquired immune deficiencies depends on avoiding or treating the causative agent or

condition (like AIDS).

Dogs will typically recover from kennel cough within a few weeks. However, secondary infections could lead to complications that could do more harm than the disease itself. Several opportunistic invaders have been recovered from the respiratory tracts of dogs with kennel cough, including Streptococcus, Pasteurella, Pseudomonas, and various coliforms. These bacteria have the potential to cause pneumonia or sepsis, which drastically increase the severity of the disease. These complications are evident in thoracic radiographic examinations. Findings will be mild in animals affected only by kennel cough, while those with complications may have evidence of segmental atelectasis and other severe side effects.

Active viremia is caused by the replication of viruses which results in viruses being introduced into the bloodstream. Examples include the measles, in which primary viremia occurs in the epithelial lining of the respiratory tract before replicating and budding out of the cell basal layer (viral shedding), resulting in viruses budding into capillaries and blood vessels.

Passive viremia is the introduction of viruses in the bloodstream without the need of active viral replication. Examples include direct inoculation from mosquitoes, through physical breaches or via blood transfusions.

The prognosis for chromoblastomycosis is very good for small lesions. Severe cases are difficult to cure, although the prognosis is still quite good. The primary complications are ulceration, lymphedema, and secondary bacterial infection. A few cases of malignant transformation to squamous cell carcinoma have been reported. Chromoblastomycosis is very rarely fatal.

Gram-negative toe web infection is a cutaneous condition that often begins with dermatophytosis.

About three quarters of people affected are children under 15 years of age, with the greatest incidence in children 6–10 years old. Therefore, children are the main reservoir of infection. Because "T. pallidum pertenue" is temperature- and humidity-dependent, yaws is found in humid tropical regions in South America, Africa, Asia and Oceania.

Mass treatment campaigns in the 1950s reduced the worldwide prevalence from 50–150 million to fewer than 2.5 million; however during the 1970s there were outbreaks in South-East Asia and there have been continued sporadic cases in South America. It is unclear how many people worldwide are infected at present.

The global prevalence of this disease and the other endemic treponematoses, bejel and pinta, was reduced by the Global Control of Treponematoses (TCP) programme between 1952 and 1964 from about 50 to 150 million cases to about 2.5 million (a 95 percent reduction). Following the cessation of this program yaws surveillance and treatment became a part of primary health systems of the affected countries. However incomplete eradication led to a resurgence of yaws in the 1970s with the largest number of case found in the Western Africa region.

Following the development of orally administered azithromycin as a treatment, the WHO has targeted yaws for eradication by 2020.

Although no specific treatment for acute infection with SuHV1 is available, vaccination can alleviate clinical signs in pigs of certain ages. Typically, mass vaccination of all pigs on the farm with a modified live virus vaccine is recommended. Intranasal vaccination of sows and neonatal piglets one to seven days old, followed by intramuscular (IM) vaccination of all other swine on the premises, helps reduce viral shedding and improve survival. The modified live virus replicates at the site of injection and in regional lymph nodes. Vaccine virus is shed in such low levels, mucous transmission to other animals is minimal. In gene-deleted vaccines, the thymidine kinase gene has also been deleted; thus, the virus cannot infect and replicate in neurons. Breeding herds are recommended to be vaccinated quarterly, and finisher pigs should be vaccinated after levels of maternal antibody decrease. Regular vaccination results in excellent control of the disease. Concurrent antibiotic therapy via feed and IM injection is recommended for controlling secondary bacterial pathogens.

Derzsy's disease is caused by a virus from the Parvoviridae family. It affects geese and Muscovy ducks.

The virus is shed in the faeces and thus transmission is horizontal, via the direct faecal-oral route and also indirectly via fomites. Vertical transmission is also possible.

Clinical disease only occurs in young geese and ducks between birth and 4–5 weeks of age.

SuHV1 can be used to analyze neural circuits in the central nervous system (CNS). For this purpose the attenuated (less virulent) Bartha SuHV1 strain is commonly used and is employed as a retrograde and anterograde transneuronal tracer. In the retrograde direction, SuHV1-Bartha is transported to a neuronal cell body via its axon, where it is replicated and dispersed throughout the cytoplasm and the dendritic tree. SuHV1-Bartha released at the synapse is able to cross the synapse to infect the axon terminals of synaptically connected neurons, thereby propagating the virus; however, the extent to which non-synaptic transneuronal transport may also occur is uncertain. Using temporal studies and/or genetically engineered strains of SuHV1-Bartha, second, third, and higher order neurons may be identified in the neural network of interest.

Primary varicella occurs in all countries worldwide. In 2013 the disease resulted in 7,000 deaths – down from 8,900 in 1990.

In temperate countries, chickenpox is primarily a disease of children, with most cases occurring during the winter and spring, most likely due to school contact. It is one of the classic diseases of childhood, with the highest prevalence in the 4–10-year-old age group. Like rubella, it is uncommon in preschool children. Varicella is highly communicable, with an infection rate of 90% in close contacts. In temperate countries, most people become infected before adulthood, and 10% of young adults remain susceptible.

In the tropics, chickenpox often occurs in older people and may cause more serious disease. In adults, the pock marks are darker and the scars more prominent than in children.

In the United States, the Centers for Disease Control and Prevention (CDC) does not require state health departments to report infections of chickenpox, and only 31 states currently volunteer this information. However, in a 2013 study conducted by the social media disease surveillance tool called Sickweather, anecdotal reports of chickenpox infections on Facebook and Twitter were used to measure and rank states with the most infections per capita, with Maryland, Tennessee and Illinois in the top three.

It is currently thought that it may be possible to eradicate yaws although it is not certain that humans are the only reservoir of infection. A single injection of long-acting penicillin or other beta lactam antibiotic cures the disease and is widely available; and the disease is believed to be highly localised.

In April 2012, WHO initiated a new global campaign for the eradication of yaws, which has been on the WHO eradication list since 2011. According to the official roadmap, elimination should be achieved by 2020.

Prior to the most recent WHO campaign, India launched its own national yaws elimination campaign which appears to have been successful.

Certification for disease-free status requires an absence of the disease for at least five years. In India this happened on 19 September 2011. In 1996 there were 3,571 yaws cases in India; in 1997 after a serious elimination effort began the number of cases fell to 735. By 2003 the number of cases was 46. The last clinical case in India was reported in 2003 and the last latent case in 2006. India is a country where yaws is now considered to have been eliminated

In March 2013, WHO convened a new meeting of yaws experts in Geneva to further discuss the strategy of the new eradication campaign. The meeting was significant, and representatives of most countries where yaws is endemic attended and described the epidemiological situation at the national level. The disease is currently known to be present in Indonesia and Timor-Leste in South-East Asia; Papua New Guinea, the Solomon Islands and Vanuatu in the Pacific region; and Benin, Cameroon, Central African Republic, Congo, Côte d'Ivoire, Democratic Republic of Congo, Ghana and Togo in Africa. As reported at the meeting, in several such countries, mapping of the disease is still patchy and will need to be completed before any serious eradication effort could be enforced.

Condom use reduces the likelihood of transmission during sex, but does not completely eliminate the risk. The Centers for Disease Control and Prevention (CDC) states, "Correct and consistent use of latex condoms can reduce the risk of syphilis only when the infected area or site of potential exposure is protected. However, a syphilis sore outside of the area covered by a latex condom can still allow transmission, so caution should be exercised even when using a condom."

Abstinence from intimate physical contact with an infected person is effective at reducing the transmission of syphilis. The CDC states, "The surest way to avoid transmission of sexually transmitted diseases, including syphilis, is to abstain from sexual contact or to be in a long-term mutually monogamous relationship with a partner who has been tested and is known to be uninfected."