PandemicA pandemic (paen'dEmIk ) is an epidemic of an infectious disease that has spread across a large region, for instance multiple continents or worldwide, affecting a substantial number of individuals. Widespread endemic diseases with a stable number of infected individuals such as recurrences of seasonal influenza are generally excluded as they occur simultaneously in large regions of the globe rather than being spread worldwide. Throughout human history, there have been a number of pandemics of diseases such as smallpox.
AsymptomaticAsymptomatic (or clinically silent) is an adjective categorising the medical conditions (i.e. injuries or diseases) that patients carry but without experiencing their symptoms, despite an explicit diagnosis (e.g. a positive medical test). Pre-symptomatic is the adjective categorising the time periods during which the medical conditions are asymptomatic. Subclinical and paucisymptomatic are other adjectives categorising either the asymptomatic infections (i.e.
Disease vectorIn epidemiology, a disease vector is any living agent that carries and transmits an infectious pathogen to another living organism; agents regarded as vectors are organisms, such as parasites or microbes. The first major discovery of a disease vector came from Ronald Ross in 1897, who discovered the malaria pathogen when he dissected a mosquito. Arthropods form a major group of pathogen vectors with mosquitoes, flies, sand flies, lice, fleas, ticks, and mites transmitting a huge number of pathogens.
BacteriaBacteria (bækˈtɪəriə; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria play a vital role in many stages of the nutrient cycle by recycling nutrients and the fixation of nitrogen from the atmosphere.
MumpsMumps is a viral disease caused by the mumps virus that is preventable with vaccination. Initial symptoms of mumps are non-specific and include fever, headache, malaise, muscle pain, and loss of appetite. These symptoms are usually followed by painful swelling of the parotid glands, called parotitis, which is the most common symptom of a mumps infection. Symptoms typically occur 16 to 18 days after exposure to the virus and resolve within two weeks. About one third of infections are asymptomatic.
ZoonosisA zoonosis (zoʊˈɒnəsɪs,_ˌzoʊəˈnoʊsɪs; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a bacterium, virus, parasite or prion) that can jump from a non-human (usually a vertebrate) to a human and vice versa. Major modern diseases such as Ebola virus disease and salmonellosis are zoonoses. HIV was a zoonotic disease transmitted to humans in the early part of the 20th century, though it has now evolved into a separate human-only disease.
PneumoniaPneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity of the condition is variable. Pneumonia is usually caused by infection with viruses or bacteria, and less commonly by other microorganisms. Identifying the responsible pathogen can be difficult. Diagnosis is often based on symptoms and physical examination.
RubellaRubella, also known as German measles or three-day measles, is an infection caused by the rubella virus. This disease is often mild, with half of people not realizing that they are infected. A rash may start around two weeks after exposure and last for three days. It usually starts on the face and spreads to the rest of the body. The rash is sometimes itchy and is not as bright as that of measles. Swollen lymph nodes are common and may last a few weeks. A fever, sore throat, and fatigue may also occur.
Eradication of infectious diseasesThe eradication of infectious diseases is the reduction of an infectious disease's prevalence in the global host population to zero. Two infectious diseases have successfully been eradicated: smallpox in humans, and rinderpest in ruminants. There are four ongoing programs, targeting the human diseases poliomyelitis (polio), yaws, dracunculiasis (Guinea worm), and malaria. Five more infectious diseases have been identified as potentially eradicable with current technology by the Carter Center International Task Force for Disease Eradication—measles, mumps, rubella, lymphatic filariasis (elephantiasis) and cysticercosis (pork tapeworm).
Whooping coughWhooping cough, also known as pertussis or the 100-day cough, is a highly contagious, vaccine-preventable bacterial disease. Initial symptoms are usually similar to those of the common cold with a runny nose, fever, and mild cough, but these are followed by two or three months of severe coughing fits. Following a fit of coughing, a high-pitched whoop sound or gasp may occur as the person breathes in. The violent coughing may last for 10 or more weeks, hence the phrase "100-day cough".
