Blood for blood transfusion is screened for many bloodborne diseases. Additionally, a technique that uses a combination of riboflavin and UV light to inhibit the replication of these pathogens by altering their nucleic acids can be used to treat blood components prior to their transfusion, and can reduce the risk of disease transmission.

A technology using the synthetic psoralen, amotosalen HCl, and UVA light (320–400 nm) has been implemented in European blood centers for the treatment of platelet and plasma components to prevent transmission of bloodborne diseases caused by bacteria, viruses and protozoa.

Blood poses the greatest threat to health in a laboratory or clinical setting due to needlestick injuries ("e.g.", lack of proper needle disposal techniques and/or safety syringes). These risks are greatest among healthcare workers, including: nurses, surgeons, laboratory assistants, doctors, phlebotomists, and laboratory technicians. These roles often require the use of syringes for blood draws or to administer medications.

The Occupational Safety and Health Administration (OSHA) prescribes 5 rules that are required for a healthcare facility to follow in order to reduce the risk of employee exposure to bloodborne pathogens. They are:

- Written exposure control plan

- Engineering controls (Sharps containers, detachable and retractable needles, syringe caps, etc.)

- Safe Work Practices and Safety Devices

- Hepatitis B vaccine available to employees

- Education and post-exposure follow up

These controls, while general, serve to greatly reduce the incidence of bloodborne disease transmission in occupational settings of healthcare workers.

There are 26 different viruses that have been shown to present in healthcare workers as a result of occupational exposure. The most common bloodborne diseases are hepatitis B (HBV), hepatitis C (HCV), and human immunodeficiency virus (HIV). Exposure is possible through blood of an infected patient splashing onto mucous membranes; however, the greatest exposure risk was shown to occur during percutaneous injections performed for vascular access. These include blood draws, as well as catheter placement, as both typically use hollow bore needles. Preventative measures for occupational exposure include standard precautions (hand washing, sharp disposal containers), as well as additional education and preventative measures. Advancements in the design of safety engineered devices have played a significant role in decreasing rates of occupational exposure to bloodborne disease. According to the Massachusetts Sharps Injury Surveillance System, needle devices without safety features accounted for 53% of the 2010 reported sharps injuries. Safer sharps devices now have engineering controls, such as a protective shield over the needle, and sharps containers that have helped to decrease this statistic. These safer alternatives are highly effective in substantially reducing injuries. For instance, almost 83% of injuries from hollow bore needles can be prevented with the use of safer sharps devices.

The U.S. Centers for Disease Control and Prevention (CDC) publishes a journal "Emerging Infectious Diseases" that identifies the following factors contributing to disease emergence:

- Microbial adaption; e.g. genetic drift and genetic shift in Influenza A

- Changing human susceptibility; e.g. mass immunocompromisation with HIV/AIDS

- Climate and weather; e.g. diseases with zoonotic vectors such as West Nile Disease (transmitted by mosquitoes) are moving further from the tropics as the climate warms

- Change in human demographics and trade; e.g. rapid travel enabled SARS to rapidly propagate around the globe

- Economic development; e.g. use of antibiotics to increase meat yield of farmed cows leads to antibiotic resistance

- Breakdown of public health; e.g. the current situation in Zimbabwe

- Poverty and social inequality; e.g. tuberculosis is primarily a problem in low-income areas

- War and famine

- Bioterrorism; e.g. 2001 Anthrax attacks

- Dam and irrigation system construction; e.g. malaria and other mosquito borne diseases

An emerging infectious disease (EID) is an infectious disease whose incidence has increased in the past 20 years and could increase in the near future. Emerging infections account for at least 12% of all human pathogens. EIDs are caused by newly identified species or strains (e.g. Severe acute respiratory syndrome, HIV/AIDS) that may have evolved from a known infection (e.g. influenza) or spread to a new population (e.g. West Nile fever) or to an area undergoing ecologic transformation (e.g. Lyme disease), or be "reemerging" infections, like drug resistant tuberculosis. Nosocomial (hospital-acquired) infections, such as methicillin-resistant Staphylococcus aureus are emerging in hospitals, and extremely problematic in that they are resistant to many antibiotics. Of growing concern are adverse synergistic interactions between emerging diseases and other infectious and non-infectious conditions leading to the development of novel syndemics. Many emerging diseases are zoonotic - an animal reservoir incubates the organism, with only occasional transmission into human populations.

A list of the more common and well-known diseases associated with infectious pathogens is provided and is not intended to be a complete listing.

Other causes or associations of disease are: a compromised immune system, environmental toxins, radiation exposure, diet and lifestyle choices, stress, and genetics. Diseases may also be multifactorial, requiring multiple factors to induce disease. For example: in a murine model, Crohn's disease can be precipitated by a norovirus, but only when both a specific gene variant is present and a certain toxin has damaged the gut.

Mosquito-borne diseases, such as dengue fever and malaria, typically affect third world countries and areas with tropical climates. Mosquito vectors are sensitive to climate changes and tend to follow seasonal patterns. Between years there are often dramatic shifts in incidence rates. The occurrence of this phenomenon in endemic areas makes mosquito-borne viruses difficult to treat.

Dengue fever is caused by infection through viruses of the family Flaviviridae. The illness is most commonly transmitted by Aedes aegypti mosquitoes in tropical and subtropical regions. Dengue virus has four different serotypes, each of which are antigenically related but have limited cross-immunity to reinfection.

Although dengue fever has a global incidence of 50-100 million cases, only several hundreds of thousands of these cases are life-threatening. The geographic prevalence of the disease can be examined by the spread of the Aedes aegypti. Over the last twenty years, there has been a geographic spread of the disease. Dengue incidence rates have risen sharply within urban areas which have recently become endemic hot spots for the disease. The recent spread of Dengue can also be attributed to rapid population growth, increased coagulation in urban areas, and global travel. Without sufficient vector control, the dengue virus has evolved rapidly over time, posing challenges to both government and public health officials.

Malaria is caused by a protozoan called Plasmodium falciparum. P. falciparum parasites are transmitted mainly by the Anopheles gambiae complex in rural Africa. In just this area, P. falciparum infections comprise an estimated 200 million clinical cases and 1 million annual deaths. 75% of individuals afflicted in this region are children. As with dengue, changing environmental conditions have led to novel disease characteristics. Due to increased illness severity, treatment complications, and mortality rates, many public health officials concede that malaria patterns are rapidly transforming in Africa. Scarcity of health services, rising instances of drug resistance, and changing vector migration patterns are factors that public health officials believe contribute to malaria’s dissemination.

Climate heavily affects mosquito vectors of malaria and dengue. Climate patterns influence the lifespan of mosquitos as well as the rate and frequency of reproduction. Climate change impacts have been of great interest to those studying these diseases and their vectors. Additionally, climate impacts mosquito blood feeding patterns as well as extrinsic incubation periods. Climate consistency gives researchers an ability to accurately predict annual cycling of the disease but recent climate unpredictability has eroded researchers’ ability to track the disease with such precision.

The arboviruses have expanded their geographic range and infected populations that had no recent community knowledge of the diseases carried by the "Aedes aegypti" mosquito. Education and community awareness campaigns are necessary for prevention to be effective. Communities are educated on how the disease is spread, how they can protect themselves from infection and the symptoms of infection. Community health education programs can identify and address the social/economic and cultural issues that can hinder preventative measures. Community outreach and education programs can identify which preventative measures a community is most likely to employ. Leading to a targeted prevention method that has a higher chance of success in that particular community. Community outreach and education includes engaging community health workers and local healthcare providers, local schools and community organizations to educate the public on mosquito vector control and disease prevention.

Babies can also become infected by their mothers during birth. Some infectious agents may be transmitted to the embryo or fetus in the uterus, while passing through the birth canal, or even shortly after birth. The distinction is important because when transmission is primarily during or after birth, medical intervention can help prevent infections in the infant.

During birth, babies are exposed to maternal blood, body fluids, and to the maternal genital tract without the placental barrier intervening. Because of this, blood-borne microorganisms (hepatitis B, HIV), organisms associated with sexually transmitted disease (e.g., "Neisseria gonorrhoeae" and "Chlamydia trachomatis"), and normal fauna of the genitourinary tract (e.g., "Candida albicans") are among those commonly seen in infection of newborns.

"Hepatitis B" is caused by hepatitis B virus, a hepadnavirus that can cause both acute and chronic hepatitis. Chronic hepatitis develops in the 15% of adults who are unable to eliminate the virus after an initial infection. Identified methods of transmission include blood (blood transfusion, now rare), unsanitary tattoos, sexually (through sexual intercourse or through contact with blood or bodily fluids), or via mother to child by breast feeding (minimal evidence of transplacental crossing). However, in about half of cases the source of infection cannot be determined. Blood contact can occur by sharing syringes in intravenous drug use, shaving accessories such as razor blades, or touching wounds on infected persons. Needle-exchange programmes have been created in many countries as a form of prevention.

Patients with chronic hepatitis B have antibodies against hepatitis B, but these antibodies are not enough to clear the infection of the affected liver cells. The continued production of virus combined with antibodies is a likely cause of the immune complex disease seen in these patients. A vaccine is available that will prevent infection from hepatitis B for life. Hepatitis B infections result in 500,000 to 1,200,000 deaths per year worldwide due to the complications of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Hepatitis B is endemic in a number of (mainly South-East Asian) countries, making cirrhosis and hepatocellular carcinoma big killers. There are six treatment options approved by the U.S. Food and Drug Administration (FDA) available for persons with a chronic hepatitis B infection: alpha-interferon, pegylated interferon, adefovir, entecavir, telbivudine, and lamivudine. About 65% of persons on treatment achieve a sustained response.

The most common cause of hepatitis is viral. Although they are classified under the disease hepatitis, these viruses are not all related.

In 2012, the World Health Organization estimated that vaccination prevents 2.5 million deaths each year. If there is 100% immunization, and 100% efficacy of the vaccines, one out of seven deaths among young children could be prevented, mostly in developing countries, making this an important global health issue. Four diseases were responsible for 98% of vaccine-preventable deaths: measles, "Haemophilus influenzae" serotype b, pertussis, and neonatal tetanus.

The Immunization Surveillance, Assessment and Monitoring program of the WHO monitors and assesses the safety and effectiveness of programs and vaccines at reducing illness and deaths from diseases that could be prevented by vaccines.

Vaccine-preventable deaths are usually caused by a failure to obtain the vaccine in a timely manner. This may be due to financial constraints or to lack of access to the vaccine. A vaccine that is generally recommended may be medically inappropriate for a small number of people due to severe allergies or a damaged immune system. In addition, a vaccine against a given disease may not be recommended for general use in a given country, or may be recommended only to certain populations, such as young children or older adults. Every country makes its own vaccination recommendations, based on the diseases that are common in its area and its healthcare priorities. If a vaccine-preventable disease is uncommon in a country, then residents of that country are unlikely to receive a vaccine against it. For example, residents of Canada and the United States do not routinely receive vaccines against yellow fever, which leaves them vulnerable to infection if travelling to areas where risk of yellow fever is highest (endemic or transitional regions).

The list below shows the main diseases that can be passed via the fecal–oral route. They are grouped by the type of pathogen involved in disease transmission.

Each type of vertically transmitted infection has a different prognosis. The stage of the pregnancy at the time of infection also can change the effect on the newborn.

Waterborne diseases are diseases caused by pathogenic microorganisms that most commonly are transmitted in contaminated fresh water. This is one particular type of fecal-oral transmission.

Neglected tropical diseases also contains many diseases transmitted via the fecal-oral route.

Waterborne diseases can have a significant impact on the economy, locally as well as internationally. People who are infected by a waterborne disease are usually confronted with related costs and not seldom with a huge financial burden. This is especially the case in less developed countries. The financial losses are mostly caused by e.g. costs for medical treatment and medication, costs for transport, special food, and by the loss of manpower. Many families must even sell their land to pay for treatment in a proper hospital. On average, a family spends about 10% of the monthly households income per person infected.

The term waterborne disease is reserved largely for infections that predominantly are transmitted through contact with or consumption of infected water. Trivially, many infections may be transmitted by microbes or parasites that accidentally, possibly as a result of exceptional circumstances, have entered the water, but the fact that there might be an occasional freak infection need not mean that it is useful to categorise the resulting disease as "waterborne". Nor is it common practice to refer to diseases such as malaria as "waterborne" just because mosquitoes have aquatic phases in their life cycles, or because treating the water they inhabit happens to be an effective strategy in control of the mosquitoes that are the vectors.

Microorganisms causing diseases that characteristically are waterborne prominently include protozoa and bacteria, many of which are intestinal parasites, or invade the tissues or circulatory system through walls of the digestive tract. Various other waterborne diseases are caused by viruses. (In spite of philosophical difficulties associated with defining viruses as "organisms", it is practical and convenient to regard them as microorganisms in this connection.)

Yet other important classes of water-borne diseases are caused by metazoan parasites. Typical examples include certain Nematoda, that is to say "roundworms". As an example of water-borne Nematode infections, one important waterborne nematodal disease is Dracunculiasis. It is acquired by swallowing water in which certain copepoda occur that act as vectors for the Nematoda. Anyone swallowing a copepod that happens to be infected with Nematode larvae in the genus Dracunculus, becomes liable to infection. The larvae cause guinea worm disease.

Another class of waterborne metazoan pathogens are certain members of the Schistosomatidae, a family of blood flukes. They usually infect victims that make skin contact with the water. Blood flukes are pathogens that cause Schistosomiasis of various forms, more or less seriously affecting hundreds of millions of people worldwide.

Long before modern studies had established the germ theory of disease, or any advanced understanding of the nature of water as a vehicle for transmitting disease, traditional beliefs had cautioned against the consumption of water, rather favouring processed beverages such as beer, wine and tea. For example, in the camel caravans that crossed Central Asia along the Silk Road, the explorer Owen Lattimore noted, "The reason we drank so much tea was because of the bad water. Water alone, unboiled, is never drunk. There is a superstition that it causes blisters on the feet."

The study of RRF has been recently facilitated by the development of a mouse model. Mice infected with RRV develop hind-limb arthritis/arthralgia which is similar to human disease. The disease in mice is characterized by an inflammatory infiltrate including macrophages which are immunopathogenic and exacerbate disease. Furthermore, mice deficient in the C3 protein do not suffer from severe disease following infection. This indicates that an aberrant innate immune response is responsible for severe disease following RRV infection.

Those dwelling in urban areas (which typically experience rodent problems) have a higher risk of contracting Rickettsialpox.

A "vaccine-preventable disease" is an infectious disease for which an effective preventive vaccine exists. If a person acquires a vaccine-preventable disease and dies from it, the death is considered a vaccine-preventable death.

The most common and serious vaccine-preventable diseases tracked by the World Health Organization (WHO) are: diphtheria, "Haemophilus influenzae" serotype b infection, hepatitis B, measles, meningitis, mumps, pertussis, poliomyelitis, rubella, tetanus, tuberculosis, and yellow fever. The WHO reports licensed vaccines being available to prevent, or contribute to the prevention and control of, 25 vaccine-preventable infections.

"A. phagocytophilum" is transmitted to humans by "Ixodes" ticks. These ticks are found in the US, Europe, and Asia. In the US, "I. scapularis" is the tick vector in the East and Midwest states, and "I. pacificus" in the Pacific Northwest. In Europe, the "I. ricinus" is the main tick vector, and "I. persulcatus" is the currently known tick vector in Asia.

The major mammalian reservoir for "A. phagocytophilum" in the eastern United States is the white-footed mouse, "Peromyscus leucopus". Although white-tailed deer and other small mammals harbor "A. phagocytophilum", evidence suggests that they are not a reservoir for the strains that cause HGA. A tick that has a blood meal from an infected reservoir becomes infected themselves. If an infected tick then latches onto a human the disease is then transmitted to the human host and "A." "phagocytophilum" symptoms can arise.

"Anaplasma phagocytophilum" shares its tick vector with other human pathogens, and about 10% of patients with HGA show serologic evidence of coinfection with Lyme disease, babesiosis, or tick-borne meningoencephalitis.

While needlestick injuries have the potential to transmit bacteria, protozoa, viruses and prions, the risk of contracting hepatitis B, hepatitis C, and HIV is the highest. The World Health Organization estimated that in 2000, 66,000 hepatitis B, 16,000 hepatitis C, and 1,000 HIV infections were caused by needlestick injuries. In places with higher rates of blood-borne diseases in the general population, healthcare workers are more susceptible to contracting these diseases from a needlestick injury.

Hepatitis B carries the greatest risk of transmission, with 10% of exposed workers eventually showing seroconversion and 10% having symptoms. Higher rates of hepatitis B vaccination among the general public and healthcare workers have reduced the risk of transmission; non-healthcare workers still have a lower HBV vaccine rate and therefore a higher risk. The hepatitis C transmission rate has been reported at 1.8%, but newer, larger surveys have shown only a 0.5% transmission rate. The overall risk of HIV infection after percutaneous exposure to HIV-infected material in the health care setting is 0.3%. Individualized risk of blood-borne infection from a used biomedical sharp is further dependent upon additional factors. Injuries with a hollow-bore needle, deep penetration, visible blood on the needle, a needle located in a deep artery or vein, or a biomedical device contaminated with blood from a terminally ill patient increase the risk for contracting a blood-borne infection.

After a needlestick injury, certain procedures must be followed to minimize the risk of infection. Lab tests of the recipient should be obtained for baseline studies, including HIV, acute hepatitis panel (HAV IgM, HBsAg, HB core IgM, HCV) and for immunized individuals, HB surface antibody. Unless already known, the infectious status of the source needs to be determined. Unless the source is known to be negative for HBV, HCV, and HIV, post-exposure prophylaxis (PEP) should be initiated, ideally within one hour of the injury.

Severe disease is more common in babies and young children, and in contrast to many other infections, it is more common in children who are relatively well nourished. Other risk factors for severe disease include female sex, high body mass index, and viral load. While each serotype can cause the full spectrum of disease, virus strain is a risk factor. Infection with one serotype is thought to produce lifelong immunity to that type, but only short-term protection against the other three. The risk of severe disease from secondary infection increases if someone previously exposed to serotype DENV-1 contracts serotype DENV-2 or DENV-3, or if someone previously exposed to DENV-3 acquires DENV-2. Dengue can be life-threatening in people with chronic diseases such as diabetes and asthma.

Polymorphisms (normal variations) in particular genes have been linked with an increased risk of severe dengue complications. Examples include the genes coding for the proteins known as TNFα, mannan-binding lectin, CTLA4, TGFβ, DC-SIGN, PLCE1, and particular forms of human leukocyte antigen from gene variations of HLA-B. A common genetic abnormality, especially in Africans, known as glucose-6-phosphate dehydrogenase deficiency, appears to increase the risk. Polymorphisms in the genes for the vitamin D receptor and FcγR seem to offer protection against severe disease in secondary dengue infection.

The bacteria are originally found in mice and cause mites feeding on the mice (usually the house mouse) to become infected. Humans will get rickettsialpox when receiving a bite from an infected mite, not from the mice themselves.

The mite is "Liponyssoides sanguineus", which was previously known as "Allodermanyssus sanguineus".

There is currently no vaccine available. The primary method of disease prevention is minimizing mosquito bites, as the disease is only transmitted by mosquitoes. Typical advice includes use of mosquito repellent and mosquito screens, wearing light coloured clothing, and minimising standing water around homes (e.g. removing Bromeliads, plant pots, garden ponds). Staying indoors during dusk/dawn hours when mosquitos are most active may also be effective. Bush camping is a common precipitant of infection so particular care is required.