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Holoendemic
A disease is holoendemic when essentially every individual in a population is infected. Although the infection is ubiquitous, symptoms of disease do not appear equally across age groups. The young are more likely to express pathogenic responses, whilst the older hosts will carry the disease asymptomatically, or with reduced damage, due to adaptive immunity. Therefore, holoendemic diseases differ from hyperendemic diseases, of which symptoms are expressed equally by members across all age groups of a population. Holoendemicity is frequently seen with malaria, specifically the strain caused by ''Plasmodium falciparum'', in several regions of sub-Saharan Africa (one study found that 98.6% of the population had traces of the pathogen within a 4 month period). While individuals of all ages risk exposure to malaria, those under the age of five are particularly susceptible to the disease. Children account for the majority of both local and global malaria cases because they lack the adaptiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infection
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable disease, is an illness resulting from an infection. Infections can be caused by a wide range of pathogens, most prominently bacteria and viruses. Hosts can fight infections using their immune system. Mammalian hosts react to infections with an innate response, often involving inflammation, followed by an adaptive response. Specific medications used to treat infections include antibiotics, antivirals, antifungals, antiprotozoals, and antihelminthics. Infectious diseases resulted in 9.2 million deaths in 2013 (about 17% of all deaths). The branch of medicine that focuses on infections is referred to as infectious disease. Types Infections are caused by infectious agents (pathogens) including: * Bacteria (e.g. ''Mycobacterium tuberculosis'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathogenic
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term ''pathogen'' came into use in the 1880s. Typically, the term ''pathogen'' is used to describe an ''infectious'' microorganism or agent, such as a virus, bacterium, protozoan, prion, viroid, or fungus. Small animals, such as helminths and insects, can also cause or transmit disease. However, these animals are usually referred to as parasites rather than pathogens. The scientific study of microscopic organisms, including microscopic pathogenic organisms, is called microbiology, while parasitology refers to the scientific study of parasites and the organisms that host them. There are several pathways through which pathogens can invade a host. The principal pathways have different episodic time frames, but soil has the longest or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymptomatic
In medicine, any disease is classified asymptomatic if a patient tests as carrier for a disease or infection but experiences no symptoms. Whenever a medical condition fails to show noticeable symptoms after a diagnosis it might be considered asymptomatic. Infections of this kind are usually called subclinical infections. Diseases such as mental illnesses or psychosomatic conditions are considered subclinical if they present some individual symptoms but not all those normally required for a clinical diagnosis. The term clinically silent is also found. Producing only a few, mild symptoms, disease is paucisymptomatic. Symptoms appearing later, after an asymptomatic incubation period, mean a pre-symptomatic period has existed. Importance Knowing that a condition is asymptomatic is important because: * It may develop symptoms later and only then require treatment. * It may resolve itself or become benign. * It may be contagious, and the contribution of asymptomatic and pre-symptomat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptive Immunity
The adaptive immune system, also known as the acquired immune system, is a subsystem of the immune system that is composed of specialized, systemic cells and processes that eliminate pathogens or prevent their growth. The acquired immune system is one of the two main immunity strategies found in vertebrates (the other being the innate immune system). Like the innate system, the adaptive immune system includes both humoral immunity components and cell-mediated immunity components and destroys invading pathogens. Unlike the innate immune system, which is pre-programmed to react to common broad categories of pathogen, the adaptive immune system is highly specific to each particular pathogen the body has encountered. Adaptive immunity creates immunological memory after an initial response to a specific pathogen, and leads to an enhanced response to future encounters with that pathogen. Antibodies are a critical part of the adaptive immune system. Adaptive immunity can provide long ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperendemic
In epidemiology, the term hyperendemic disease is used to refer to a disease which is constantly and persistently present in a population at a high rate of incidence and/or prevalence (occurrence) and which equally affects (i.e. which is equally endemic in) all age groups of that population. It is one of the various degrees of endemicity (i.e. degrees of transmission of an infectious disease). Definitions According to a more precise definition given by the Robert Koch Institute in Germany, hyperendemicity is not necessarily associated with a high incidence rate. A hyperendemic disease is one which is ubiquitously present with ongoing circulation in an endemic region with a high prevalence rate. As a result, a hyperendemic region shows a relatively low incidence rate but at the same time it poses a high risk of infection to people coming into the region. According to another definition discussing malaria, a hyperendemic region is defined to be one with a seasonally high degree of en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malaria
Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. Symptoms usually begin ten to fifteen days after being bitten by an infected mosquito. If not properly treated, people may have recurrences of the disease months later. In those who have recently survived an infection, reinfection usually causes milder symptoms. This partial resistance disappears over months to years if the person has no continuing exposure to malaria. Malaria is caused by single-celled microorganisms of the ''Plasmodium'' group. It is spread exclusively through bites of infected ''Anopheles'' mosquitoes. The mosquito bite introduces the parasites from the mosquito's saliva into a person's blood. The parasites travel to the liver where they mature and reproduce. Five species of ''Plasmodium'' can infect and be spread by h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasmodium Falciparum
''Plasmodium falciparum'' is a Unicellular organism, unicellular protozoan parasite of humans, and the deadliest species of ''Plasmodium'' that causes malaria in humans. The parasite is transmitted through the bite of a female ''Anopheles'' mosquito and causes the disease's most dangerous form, falciparum malaria. It is responsible for around 50% of all malaria cases. ''P. falciparum'' is therefore regarded as the deadliest parasite in humans. It is also associated with the development of blood cancer (Burkitt's lymphoma) and is classified as a List of IARC Group 2A carcinogens, Group 2A (probable) carcinogen. The species originated from the malarial parasite ''Laverania'' found in gorillas, around 10,000 years ago. Alphonse Laveran was the first to identify the parasite in 1880, and named it ''Oscillaria malariae''. Ronald Ross discovered its transmission by mosquito in 1897. Giovanni Battista Grassi elucidated the complete transmission from a female Anopheles, anopheline mosquit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sub-Saharan Africa
Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sovereign states and dependent territories in Africa, African countries and territories that are situated fully in that specified region, the term may also include polities that only have part of their territory located in that region, per the definition of the United Nations (UN). This is considered a non-standardized geographical region with the number of countries included varying from 46 to 48 depending on the organization describing the region (e.g. UN, WHO, World Bank, etc.). The Regions of the African Union, African Union uses a different regional breakdown, recognizing all 55 member states on the continent - grouping them into 5 distinct and standard regions. The term serves as a grouping counterpart to North Africa, which is instead ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathogen
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term ''pathogen'' came into use in the 1880s. Typically, the term ''pathogen'' is used to describe an ''infectious'' microorganism or agent, such as a virus, bacterium, protozoan, prion, viroid, or fungus. Small animals, such as helminths and insects, can also cause or transmit disease. However, these animals are usually referred to as parasites rather than pathogens. The scientific study of microscopic organisms, including microscopic pathogenic organisms, is called microbiology, while parasitology refers to the scientific study of parasites and the organisms that host them. There are several pathways through which pathogens can invade a host. The principal pathways have different episodic time frames, but soil has the longest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trachoma
Trachoma is an infectious disease caused by bacterium ''Chlamydia trachomatis''. The infection causes a roughening of the inner surface of the eyelids. This roughening can lead to pain in the eyes, breakdown of the outer surface or cornea of the eyes, and eventual blindness. Untreated, repeated trachoma infections can result in a form of permanent blindness when the eyelids turn inward. The bacteria that cause the disease can be spread by both direct and indirect contact with an affected person's eyes or nose. Indirect contact includes through clothing or flies that have come into contact with an affected person's eyes or nose. Children spread the disease more often than adults. Poor sanitation, crowded living conditions, and not enough clean water and toilets also increase spread. Efforts to prevent the disease include improving access to clean water and treatment with antibiotics to decrease the number of people infected with the bacterium. This may include treating, all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatitis B
Hepatitis B is an infectious disease caused by the ''Hepatitis B virus'' (HBV) that affects the liver; it is a type of viral hepatitis. It can cause both acute and chronic infection. Many people have no symptoms during an initial infection. For others, symptoms may appear 30 to 180 days after becoming infected and can include a rapid onset of sickness with nausea, vomiting, yellowish skin, fatigue, dark urine, and abdominal pain. Symptoms during acute infection typically last for a few weeks, though some people may feel sick for up to six months. Deaths resulting from acute stage HBV infections are rare. An HBV infection lasting longer than six months is usually considered chronic. The likelihood of developing chronic hepatitis B is higher for those who are infected with HBV at a younger age. About 90% of those infected during or shortly after birth develop chronic hepatitis B, while less than 10% of those infected after the age of five develop chronic cases. Most of those wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marquesas Islands
The Marquesas Islands (; french: Îles Marquises or ' or '; Marquesan: ' ( North Marquesan) and ' ( South Marquesan), both meaning "the land of men") are a group of volcanic islands in French Polynesia, an overseas collectivity of France in the southern Pacific Ocean. Their highest point is the peak of Mount Oave (french: Mont Oave, links=no) on Ua Pou island, at 1,230 m (4,035 ft) above sea level. Archaeological research suggests the islands were colonized in the 10th century AD by voyagers from West Polynesia. Over the centuries that followed, the islands have maintained a "remarkably uniform culture, biology and language". The Marquesas were named after the 16th century Spanish Viceroy of Peru, the Marquis of Cañete ( es, Marqués de Cañete, italic=unset) by navigator , who visited them in 1595. The Marquesas Islands constitute one of the five administrative divisions (') of French Polynesia. The capital of the Marquesas Islands' administrative subdivision is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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