A disease is a particular abnormal condition that adversely affects the structure or function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical conditions that are associated with specific signs and symptoms. A disease may be caused by external factors such as pathogens or by internal dysfunctions. For example, internal dysfunctions of the immune system can produce a variety of different diseases, including various forms of immunodeficiency, hypersensitivity, allergies, and autoimmune disorders.
A quarantine is a restriction on the movement of people, animals, and goods which is intended to prevent the spread of disease or pests. It is often used in connection to disease and illness, preventing the movement of those who may have been exposed to a communicable disease, yet do not have a confirmed medical diagnosis. It is distinct from medical isolation, in which those confirmed to be infected with a communicable disease are isolated from the healthy population.
Infectious mononucleosis, also known as glandular fever, is an infection usually caused by the Epstein–Barr virus (EBV). Most people are infected by the virus as children, when the disease produces few or no symptoms. In young adults, the disease often results in fever, sore throat, enlarged lymph nodes in the neck, and fatigue. Most people recover in two to four weeks; however, feeling tired may last for months. The liver or spleen may also become swollen, and in less than one percent of cases splenic rupture may occur.
Pharyngitis is inflammation of the back of the throat, known as the pharynx. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, difficulty swallowing, swollen lymph nodes, and a hoarse voice. Symptoms usually last 3–5 days, but can be longer depending on cause. Complications can include sinusitis and acute otitis media. Pharyngitis is a type of upper respiratory tract infection.
In epidemiology, an outbreak is a sudden increase in occurrences of a disease when cases are in excess of normal expectancy for the location or season. It may affect a small and localized group or impact upon thousands of people across an entire continent. The number of cases varies according to the disease-causing agent, and the size and type of previous and existing exposure to the agent. Outbreaks include many epidemics, which term is normally only for infectious diseases, as well as diseases with an environmental origin, such as a water or foodborne disease. They may affect a region in a country or a group of countries. Pandemics are near-global disease outbreaks when multiple and various countries around the Earth are soon infected.
Roseola, also known as sixth disease, is an infectious disease caused by certain types of human herpes viruses. Most infections occur before the age of three. Symptoms vary from absent to the classic presentation of a fever of rapid onset followed by a rash. The fever generally lasts for three to five days, while the rash is generally pink and lasts for less than three days. Complications may include febrile seizures, with serious complications being rare.
An upper respiratory tract infection (URTI) is an illness caused by an acute infection, which involves the upper respiratory tract, including the nose, sinuses, pharynx, larynx or trachea. This commonly includes nasal obstruction, sore throat, tonsillitis, pharyngitis, laryngitis, sinusitis, otitis media, and the common cold. Most infections are viral in nature, and in other instances, the cause is bacterial. URTIs can also be fungal or helminthic in origin, but these are less common.
The Control of Communicable Diseases Manual (CCDM) is one of the most widely recognized reference volumes on the topic of infectious diseases. It is useful for physicians, epidemiologists, global travelers, emergency volunteers and all who have dealt with or might have to deal with public health issues.
Gastroenteritis, also known as infectious diarrhea, is an inflammation of the gastrointestinal tract including the stomach and intestine. Symptoms may include diarrhea, vomiting, and abdominal pain. Fever, lack of energy, and dehydration may also occur. This typically lasts less than two weeks. Although it is not related to influenza, in the U.S. and U.K., it is sometimes called the "stomach flu".
The UK statutory notification system for infectious diseases is a system whereby doctors are required to notify a "proper officer" of the local authority if they are presented with a case of a serious infectious disease such as diphtheria or measles. The proper officer then sends a report to the Centre for Infections of the Health Protection Agency (HPA) in Colindale, north London.
In epidemiology, an infection is said to be endemic in a specific population or populated place when that infection is constantly present, or maintained at a baseline level, without extra infections being brought into the group as a result of travel or similar means. The term describes the distribution of an infectious disease among a group of people or within a populated area. An endemic disease always has a steady, predictable number of people getting sick, but that number can be high (hyperendemic) or low (hypoendemic), and the disease can be severe or mild. Also, a disease that is usually endemic can become epidemic.
In epidemiology, case fatality rate (CFR) – or sometimes more accurately case-fatality risk – is the proportion of people who have been diagnosed with a certain disease and end up dying of it. Unlike a disease's mortality rate, the CFR does not take into account the time period between disease onset and death. A CFR is generally expressed as a percentage. It is a measure of disease lethality, and thus may change with different treatments. CFRs are most often used for with discrete, limited-time courses, such as acute infections.
Paratyphoid fever, also known simply as paratyphoid, is a bacterial infection caused by one of three types of Salmonella enterica. Symptoms usually begin 6–30 days after exposure and are the same as those of typhoid fever. Often, a gradual onset of a high fever occurs over several days. Weakness, loss of appetite, and headaches also commonly occur. Some people develop a skin rash with rose-colored spots. Without treatment, symptoms may last weeks or months. Other people may carry the bacteria without being affected; however, they are still able to spread the disease to others. Typhoid and paratyphoid are of similar severity. Paratyphoid and typhoid fever are types of enteric fever.
An emerging infectious disease (EID) is an infectious disease whose incidence has increased recently, and could increase in the near future. The minority that are capable of developing efficient transmission between humans can become major public and global concerns as potential causes of epidemics or pandemics. Their many impacts can be economic and societal, as well as clinical. EIDs have been increasing steadily since at least 1940.
A notifiable disease is any disease that is required by law to be reported to government authorities. The collation of information allows the authorities to monitor the disease, and provides early warning of possible outbreaks. In the case of livestock diseases, there may also be the legal requirement to kill the infected livestock upon notification. Many governments have enacted regulations for reporting of both human and animal diseases.
The International Health Regulations (IHR), first adopted by the World Health Assembly in 1969 and last revised in 2005, are legally binding rules that only apply to the WHO that is an instrument that aims for international collaboration "to prevent, protect against, control, and provide a public health response to the international spread of disease in ways that are commensurate with and restricted to public health risks and that avoid unnecessary interference with international traffic and trade". The IHR is the only international legal treaty with the responsibility of empowering the World Health Organization (WHO) to act as the main global surveillance system.
A notifiable disease is one which the law requires to be reported to government authorities.
The Public Health Act 1984 is a piece of legislation for England and Wales which requires physicians to notify the 'proper officer' of the local authority of any person deemed to be suffering from a notifiable disease. It also provides powers to isolate infected individuals to prevent the spread of such a disease. The act forms the basis of various legislation connected to the COVID-19 pandemic in the United Kingdom.
The Division of Global Migration Health (DGMH), formerly the Division of Global Migration and Quarantine is the part of the U.S. government responsible for U.S. Quarantine Stations and issuing quarantine orders. It is part of the National Center for Emerging and Zoonotic Infectious Diseases within the Centers for Disease Control and Prevention (CDC).
The Weekly Epidemiological Record (WER) is a publication of the World Health Organization (WHO) that as of 2020 is in its 95th volume. It is published in English and French with the alternative title of the Relevé épidémiologique hebdomadaire. It aims to rapidly disseminate epidemiological information about outbreaks of diseases under the International Health Regulations and about communicable diseases of public health importance. This includes emerging or re-emerging diseases.
