Variola Virus | Health Dictionary

Variola Virus | Health Dictionary

Keywords of this word: Variola Virus


ADENOVIRUSES

Medical Dictionary

Viruses (see VIRUS) containing double-stranded DNA; these cause around 5 per cent of clinically recognised respiratory illnesses. Of the 40 or so known types, only a few have been properly studied to establish how they produce disease. Adenoviruses cause fever and in?ammation of the respiratory tract and mucous membranes of the eyes – symptoms resembling those of the common cold. They also cause ENTERITIS, haemorrhagic CYSTITIS and life-threatening infections in newborn babies. Infections are generally benign and self-limiting, and treatment is symptomatic and supportive, although the elderly and people with chronic chest conditions may develop secondary infections which require antibiotic treatment.... Medical Dictionary

ARBOVIRUS

Dictionary of Tropical Medicine

A class of viruses transmitted by arthropods. Name contracted from “arthropod-borne viruses”.... Dictionary of Tropical Medicine

ARBOVIRUSES

Medical Dictionary

A heterogenous group of around 500 viruses, which are transmitted to humans by ARTHROPODS. Grouped in four families, they include the viruses of DENGUE and YELLOW FEVER which are transmitted by mosquitoes.... Medical Dictionary

ARENAVIRUSES

Medical Dictionary

A group of viruses, so-called because under the electron microscope they have a sand-sprinkled (Latin, arenosus) appearance. Among the diseases in humans for which they are responsible are LASSA FEVER in West Africa, Argentinian haemorrhagic fever (mortality rate 3–15 per cent), a similar disease in Bolivia (mortality rate 18 per cent), and lymphocytic choriomeningitis, in which deaths are uncommon.... Medical Dictionary

ASTROVIRUSES

Medical Dictionary

Small round viruses (see VIRUS) with no distinctive features, which have been isolated from the stools of infants with gastroenteritis (see DIARRHOEA). Most adults have antibodies against these viruses; this suggests that infection is common. There is no treatment.... Medical Dictionary

BARMAH FOREST VIRUS

Dictionary of Tropical Medicine

A mosquito-borne arbovirus causing symptoms similar to Ross River virus infection in Australia. (See also Ross River virus).... Dictionary of Tropical Medicine

CORONAVIRUS

Dictionary of Tropical Medicine

RNA viruses causing the common cold Coronatae The taxonomic order of grooved jellyfish.... Dictionary of Tropical Medicine

CORONAVIRUSES

Medical Dictionary

Coronaviruses – so-called because in electron micrographs the spikes projecting from the virus resemble a crown – are a group of viruses which have been isolated from people with common colds (see COLD, COMMON) and have also been shown to produce common colds under experimental conditions. Their precise signi?cance in the causation of the common cold is still undetermined.... Medical Dictionary

COXSACKIE VIRUSES

Medical Dictionary

A group of viruses so-called because they were ?rst isolated from two patients with a disease resembling paralytic POLIOMYELITIS, in the village of Coxsackie in New York State. Thirty distinct types have now been identi?ed. They constitute one of the three groups of viruses included in the family of ENTEROVIRUSES, and are divided into two groups: A and B. Despite the large number of types of group A virus (24) in existence, evidence of their role in causing human disease is limited. Some, however, cause aseptic MENINGITIS, non-specicifc upper respiratory infection and MYOCARDITIS, and others cause a condition known as HERPANGINA. HAND, FOOT AND MOUTH DISEASE is another disease caused by the A group. All six types of group B virus have been associated with outbreaks of aseptic meningitis, and they are also the cause of BORNHOLM DISEASE. Epidemics of type B2 infections tend to occur in alternate years. (See VIRUS.)... Medical Dictionary

CYTOMEGALOVIRUS (CMV)

Medical Dictionary

A commonly occurring virus of the herpes virus group – the name derived from the swollen appearance of infected cells (‘cytomegalo’ = large cell). The infection is usually asymptomatic (or like mild in?uenza), but it can cause an illness similar to infectious MONONUCLEOSIS. Most people (80 per cent) will have had CMV infection by the time they are adults, but the virus can remain latent in the body and cause recurrent infections. During an acute infection the virus is excreted in saliva, breast milk and urine as well as from the vagina, and this may continue for years. CMV is transmitted naturally by saliva or during sexual contact, but blood transfusions and organ transplantations are also infection routes. Although CMV rarely causes its host any problems, when it is passed from an infected mother to her fetus in utero or to an infant during birth (from vaginal secretions) or via breast milk postnatally, the virus causes a generalised severe infection in the infant. This can involve the central nervous system and liver, causing death of the fetus or neonate. If the infant survives it may be mentally retarded, with motor disabilities, deafness and chronic liver disease. In England and Wales about 400 babies a year are born with CMV-induced disabilities. If an adult is immunode?cient (see IMMUNODEFICIENCY) because of HIV infection/AIDS or as a result of immunosuppressive treatment after an organ transplant, he or she may become seriously ill.... Medical Dictionary

EBOLA VIRUS DISEASE

Medical Dictionary

Ebola virus disease is another name for VIRAL HAEMORRHAGIC FEVER. The ebola virus is one of the most virulent micro-organisms known. Like the marburg virus (see MARBURG DISEASE), it belongs to the ?lovirus group which originates in Africa. Increased population mobility and wars have meant that the infection occasionally occurs elsewhere, with air travellers developing symptoms on returning home.

Treatment As the disease can be neither prevented nor cured, treatment is supportive, with strict anti-infection procedures essential as human-to-human transmission can occur via skin and mucous-membrane contacts. Incubation period is 5–10 days. Fever with MYALGIA and headache occur initially, often accompanied by abdominal and chest symptoms. Haemorrhagic symptoms soon develop and the victim either starts to improve in the second week or develops multi-organ failure and lapses into a coma. Mortality ranges from 25 to 90 per cent.... Medical Dictionary

ECHOVIRUSES

Medical Dictionary

Echoviruses, of which there are more than 30 known types, occur in all parts of the world. Their full name is Enteric Cytopathogenic Human Orphan (ECHO – hence the acronym). They are more common in children than in adults, and have been responsible for outbreaks of MENINGITIS, common-cold-like illnesses, gastrointestinal infections, and infections of the respiratory tract. They are particularly dangerous when they infect premature infants, and there have been several outbreaks of such infection in neonatal units, in which premature infants and other seriously ill small babies are nursed. The virus is introduced to such units by mothers, sta? and visitors who are unaware that they are carriers of the virus.... Medical Dictionary

ENTEROVIRUSES

Medical Dictionary

A family of VIRUSES which include the POLIOMYELITIS, COXSACKIE and ECHO (see ECHOVIRUSES) groups of viruses. Their importance lies in their tendency to invade the central nervous system. They receive their name from the fact that their mode of entry into the body is through the gut.... Medical Dictionary

EPSTEIN BARR VIRUS

Medical Dictionary

The virus that causes glandular fever or infectious MONONUCLEOSIS. It is similar to the viruses that cause herpes and is associated with BURKITT’S LYMPHOMA. It has been suggested as precipitating some attacks of MYALGIC ENCEPHALOMYELITIS (ME), also known as CHRONIC FATIGUE SYNDROME (CFS).... Medical Dictionary

EPSTEIN-BARR VIRUS

Herbal Medical

A large, ubiquitous, and normally benign, herpes-like virus with both DNA and capsid. It is sometimes implicated in mononucleosis and at least two types of lymphomas. Recently it has been become connected with the symptom picture called chronic fatigue syndrome (as has been CMV) and can produce many ill-defined (but subjectively distressful) symptoms, including fatigue, fevers of an unknown origin (FUO...love those acronyms!), and emotional lability. Immunosuppression, from whatever cause, allows the syndrome to occur. Many people in and out of medicine have come to regard it as both another form of Multiple Chemical Sensitivities (MCS, naturally) and a sequel to excessive medical use of immunosupressant anti­inflammatories.... Herbal Medical

HANTAVIRUS

Dictionary of Tropical Medicine

Also known as Four Corners virus. A rodent virus from the white-footed deer mouse of the USA. Causes severe respiratory disease of humans.... Dictionary of Tropical Medicine

HANTAVIRUS

Medical Dictionary

A group of viruses that infect mice, rats and voles and can also infect humans who come into contact with the excreta or secretions of these animals. Widely distributed in Asia, the USA and Europe, in Britain hantavirus usually a?ects rural and sewage workers, as well as people engaged in watersports. Many victims have a mild feverish illness; severe cases are characterised by headache, high temperature, nausea, vomiting and even shock, accompanied by skin PETECHIAE. The kidneys and sometimes the lungs are a?ected, and in severely a?ected patients mortality is high.... Medical Dictionary

HENDRA VIRUS

Dictionary of Tropical Medicine

Virus of Flying Foxes (Fruit Bats) in Australia. Can infect horses and humans. Also known as the Equine morbillivirus.... Dictionary of Tropical Medicine

HEPATITIS VIRUSES

Dictionary of Tropical Medicine

The most common causes of viral hepatitis are those caused by the Hepatitis A, B, C, D, E and G viruses. Hepatitis F virus has been described but is a doubtful entity. Other viruses which can cause hepatitis include the Epstein-Barr Virus, cytomegalovirus, and the Yellow Fever virus.... Dictionary of Tropical Medicine

HERPES SIMPLEX VIRUS

Dictionary of Tropical Medicine

Causative virus of genital herpes and herpes labalis or cold sores.... Dictionary of Tropical Medicine

HERPES VIRUSES

Medical Dictionary

One member of a group of viruses containing DNA which cause latent infections in animals and humans. Viruses from this group cause HERPES SIMPLEX, HERPES ZOSTER (shingles) and CHICKENPOX, and include CYTOMEGALOVIRUS (CCMV) and EPSTEIN-BARR VIRUS.... Medical Dictionary

HERPES ZOSTER VIRUS

Dictionary of Tropical Medicine

Causative virus of chicken pox and shingles.... Dictionary of Tropical Medicine

HIV (HUMAN IMMUNODEFICIENCY VIRUS)

Dictionary of Tropical Medicine

The name of the causative agent of AIDS.... Dictionary of Tropical Medicine

LYSSA VIRUS

Dictionary of Tropical Medicine

A group of rhabdoviruses closely related to the rabies virus. The Australian Bat Lyssa virus is found in flying foxes (fruit bats) and can cause a rabies-like disease in humans. The disease should be handled as for rabies and can be prevented by using rabies vaccine.... Dictionary of Tropical Medicine

MONKEY B VIRUS

Dictionary of Tropical Medicine

A herpes virus of monkeys that can infect humans, usually through handling monkey tissues at autopsy or in the laboratory.... Dictionary of Tropical Medicine

MYXOVIRUSES

Medical Dictionary

These include the INFLUENZA viruses A, B and C; and the PARAINFLUENZA VIRUSES, types 1 to

3. Myxoviruses, which are one of a group of RNA-containing viruses, have an a?nity for protein receptors in red blood cells.... Medical Dictionary

NIPAH VIRUS

Dictionary of Tropical Medicine

Virus first identified from the village of Nipah in Malaysia. Carried by flying foxes (fruit bats). Can infect pigs and humans.... Dictionary of Tropical Medicine

PAPOVA VIRUSES

Medical Dictionary

These include the human papilloma viruses (HPV), of which nearly a hundred strains have been identi?ed. HPV cause verrucae (see WARTS) on skin and, less often, on the mucous membranes of mouth, larynx, genitalia and the cervix. Some strains may predispose to eventual cancer.... Medical Dictionary

PARAINFLUENZA VIRUSES

Medical Dictionary

These are included in the paramyxoviruses (see MYXOVIRUSES) and divided into four types, all of which cause infection of the respiratory system (see RESPIRATION). Infection with type 3 begins in May, reaches a maximum in July or August and returns to base-line level in October. Types 1 and 2 are predominantly winter viruses. Children are commonly a?ected and the manifestations include CROUP, fever, and a rash.... Medical Dictionary

PARVOVIRUSES

Medical Dictionary

(from parvus, Latin for small) is a group of viruses responsible for outbreaks of WINTER VOMITING DISEASE. One strain is the cause of ERYTHEMA infectiosum (slapped-cheek syndrome).... Medical Dictionary

PICORNA VIRUSES

Medical Dictionary

These infectious agents derive their name from pico (small) and from RNA (because they contain ribonuleic acid). They are a group of viruses which includes the ENTEROVIRUSES and the RHINOVIRUSES.... Medical Dictionary

RESPIRATORY SYNCYTIAL VIRUS (RSV)

Medical Dictionary

Usually known as RSV, this is one of the MYXOVIRUSES. It is among the major causes of BRONCHIOLITIS and PNEUMONIA among infants aged under 6 months; its incidence has been increasing, possibly due to atmospheric pollution.... Medical Dictionary

RETROVIRUS

Medical Dictionary

A VIRUS containing ribonucleic acid (RNA) which is able to change its genetic material into deoxyribonucleic acid (DNA) using an ENZYME called reverse transcriptase. This conversion enables the retrovirus to become integrated into the host cell’s DNA. Retroviruses are believed to be involved in the development of some cancers; they are also associated with disorders linked with an impaired immune system (see IMMUNITY). HIV is a retrovirus.

Retroviruses are also used in the development of gene therapy (see GENETIC ENGINEERING).... Medical Dictionary

RHABDOVIRUSES

Medical Dictionary

A group of viruses which includes the RABIES virus.... Medical Dictionary

RHINOVIRUSES

Medical Dictionary

A large group of viruses; to date around 80 distinct rhinoviruses have been identi?ed. Their practical importance is that some of them are responsible for around one-quarter of the cases of the COMMON COLD.... Medical Dictionary

ROSS RIVER VIRUS

Dictionary of Tropical Medicine

A mosquito-borne arbovirus causing epidemic polyarthritis in Australia and certain islands of the Western Pacific to which it has spread.... Dictionary of Tropical Medicine

ROTAVIRUSES

Medical Dictionary

A group of viruses (so-called because of their wheel-like structure: rota is Latin for wheel) which are a common cause of GASTROENTERITIS in infants (see also DIARRHOEA). They cause from 25 to 80 per cent of childhood diarrhoea in di?erent parts of the world, and in the United Kingdom they are responsible for 60– 65 per cent of cases. They infect only the cells lining the small intestine. In the UK, death from rotavirus is rare.... Medical Dictionary

SLOW VIRUS

Dictionary of Tropical Medicine

See prion.... Dictionary of Tropical Medicine

VARIOLA

Medical Dictionary

Another name for SMALLPOX.... Medical Dictionary

VIRUS

Medical Dictionary

An extremely small infective agent requiring living cells for replication. Are either RNA or DNA, never both.... Medical Dictionary

VIRUS

Dictionary of Tropical Medicine

The term applied to a group of infective agents which are so small that they are able to pass through the pores of collodion ?lters. They are responsible for some of the most devastating diseases a?ecting humans: for example, INFLUENZA, POLIOMYELITIS, SMALLPOX and YELLOW FEVER. The virus of in?uenza measures 80 nanometres, whereas the STAPHYLOCOCCUS measures 1,000 nanometres (1 nanometre = one thousand-millionth of a metre).

A single virus particle, known as a virion, comprises an inner core of NUCLEIC ACID which is surrounded by one or two protective coverings (capsid) made of protein. Sometimes the capsid is enclosed by another layer called the viral envelope (also a protein structure). The envelope often disintegrates when the virus invades a cell. Viruses enter cells and then indulge in a complex and variable process of replication using some of the cells’ own structure. Viruses may stay in a host’s nucleus, being reactivated months or years later. There are more than a score of large families of viruses, from papoviruses, which cause WARTS, through HERPES viruses (cold sores, CHICKENPOX, SHINGLES) and orthomyxoviruses (in?uenza), to corona viruses (common cold) and retroviruses (AIDS/HIV). Viral diseases are more dif?cult to treat than those caused by bacteria: ANTIBIOTICS are ine?ective but INTERFERON, a group of natural substances, shows promise. IMMUNISATION is the most e?ective way of combating viral infections; smallpox, poliomyelitis, MUMPS, MEASLES and RUBELLA are examples of viral diseases which have been successfully combated. Research is progressing to ?nd a vaccine against HIV.... Dictionary of Tropical Medicine

WEST NILE VIRUS

Medical Dictionary

A mosquito-borne viral infection that is normally harmless to healthy people who, if infected, develop a mild ?u-like illness. However, if the elderly and those in poor health, particularly immunocompromised patients, are infected, they may develop fatal in?ammation of the brain and spinal cord. In Israel in 2000, 12 people died and more than 155 survived an outbreak; and in New York in 1999, more than 60 people were infected, of whom six died. The disease was ?rst reported in Uganda in 1937 and became ENDEMIC in the Middle East and Africa, recently spreading to Europe, central Asia, Oceania and America. Mosquitoes bearing the ?aviviridae-family virus usually contract it by biting infected poultry, but the infection has been found in mammals, such as cats, dogs and horses.... Medical Dictionary