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Human-to-human Transmission
Human-to-human transmission (HHT) is an epidemiologic vector, especially in case the disease is borne by individuals known as superspreaders. In these cases, the basic reproduction number of the virus, which is the average number of additional people that a single case will infect without any preventative measures, can be as high as 203.9. Interhuman transmission is a synonym for HHT. The World Health Organization designation of a pandemic hinges on the demonstrable fact that there is sustained HHT in two regions of the world. Synopsis Relevant pathogens may be viruses, bacteria, or fungi, and they may be spread through breathing, talking, coughing, sneezing, spraying of liquids, toilet flushing or any activities which generate aerosol particles or droplets or generate fomites, such as raising of dust. A 2007 study showed that influenza virus was still active on stainless steel 24 hours after contamination. Though on hands it survives only for five minutes, the constant conta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidemiologic
Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and determinants In mathematics, the determinant is a scalar value that is a function of the entries of a square matrix. It characterizes some properties of the matrix and the linear map represented by the matrix. In particular, the determinant is nonzero if and ... of health and disease conditions in a defined population. It is a cornerstone of public health, and shapes policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare. Epidemiologists help with study design, collection, and statistical analysis of data, amend interpretation and dissemination of results (including peer review and occasional systematic review). Epidemiology has helped develop methodology used in clinical research, public health studies, and, to a lesser extent, basic research in the biological sciences. Major areas of epidemiological study includ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Measles
Measles is a highly contagious infectious disease caused by measles virus. Symptoms usually develop 10–12 days after exposure to an infected person and last 7–10 days. Initial symptoms typically include fever, often greater than , cough, runny nose, and inflamed eyes. Small white spots known as Koplik's spots may form inside the mouth two or three days after the start of symptoms. A red, flat rash which usually starts on the face and then spreads to the rest of the body typically begins three to five days after the start of symptoms. Common complications include diarrhea (in 8% of cases), middle ear infection (7%), and pneumonia (6%). These occur in part due to measles-induced immunosuppression. Less commonly seizures, blindness, or inflammation of the brain may occur. Other names include ''morbilli'', ''rubeola'', ''red measles'', and ''English measles''. Both rubella, also known as ''German measles'', and roseola are different diseases caused by unrelated viruses. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avian Flu
Avian influenza, known informally as avian flu or bird flu, is a variety of influenza caused by viruses adapted to birds.Chapter Two : Avian Influenza by Timm C. Harder and Ortrud Werner in ''Influenza Report 2006'' CDC has a showing the relationship between dozens of highly pathogenic varieties of the Z genotype of avian flu virus H5N1 and ancestral strains. The type with the greatest risk is highly pathogenic av ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MERS
Middle East respiratory syndrome (MERS) is a viral respiratory infection caused by ''Middle East respiratory syndrome–related coronavirus'' (MERS-CoV). Symptoms may range from none, to mild, to severe. Typical symptoms include fever, cough, diarrhea, and shortness of breath. The disease is typically more severe in those with other health problems. The first case was identified in June 2012 by Egyptian physician Ali Mohamed Zaki at the Dr. Soliman Fakeeh Hospital in Jeddah, Saudi Arabia, and most cases have occurred in the Arabian Peninsula. Over 2,500 cases have been reported as of January 2021, including 45 cases in the year 2020. About 35% of those who are diagnosed with the disease die from it. Larger outbreaks have occurred in South Korea in 2015 and in Saudi Arabia in 2018. MERS-CoV is a coronavirus believed to be originally from bats. However, humans are typically infected from camels, either during direct contact or indirectly. Spread between humans typical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SARS-CoV-1
Severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1; or Severe acute respiratory syndrome coronavirus, SARS-CoV) is a strain of coronavirus that causes severe acute respiratory syndrome (SARS), the respiratory illness responsible for the 2002–2004 SARS outbreak. It is an enveloped, positive-sense, single-stranded RNA virus that infects the epithelial cells within the lungs. The virus enters the host cell by binding to angiotensin-converting enzyme 2. It infects humans, bats, and palm civets. On April 16, 2003, following the outbreak of SARS in Asia and secondary cases elsewhere in the world, the World Health Organization (WHO) issued a press release stating that the coronavirus identified by a number of laboratories was the official cause of SARS. The Centers for Disease Control and Prevention (CDC) in the United States and the National Microbiology Laboratory (NML) in Canada identified the SARS-CoV-1 genome in April 2003. Scientists at Erasmus University in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monkeypox
Monkeypox (also called mpox by the WHO) is an infectious viral disease that can occur in humans and some other animals. Symptoms include fever, swollen lymph nodes, and a rash that forms blisters and then crusts over. The time from exposure to onset of symptoms ranges from five to twenty-one days. The duration of symptoms is typically two to four weeks. There may be mild symptoms, and it may occur without any symptoms being apparent. The classic presentation of fever and muscle pains, followed by swollen glands, with lesions all at the same stage, has not been found to be common to all outbreaks. Cases may be severe, especially in children, pregnant women or people with suppressed immune systems. The disease is caused by the monkeypox virus, a zoonotic virus in the genus ''Orthopoxvirus''. The variola virus, the causative agent of smallpox, is also in this genus. Of the two types in humans, cladeII (formerly West African clade) causes a less severe disease than the Central ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norovirus
Norovirus, sometimes referred to as the winter vomiting disease, is the most common cause of gastroenteritis. Infection is characterized by non-bloody diarrhea, vomiting, and stomach pain. Fever or headaches may also occur. Symptoms usually develop 12 to 48 hours after being exposed, and recovery typically occurs within one to three days. Complications are uncommon, but may include dehydration, especially in the young, the old, and those with other health problems. The virus is usually spread by the fecal–oral route. This may be through contaminated food or water or person-to-person contact. It may also spread via contaminated surfaces or through air from the vomit of an infected person. Risk factors include unsanitary food preparation and sharing close quarters. Diagnosis is generally based on symptoms. Confirmatory testing is not usually available but may be performed by public health agencies during outbreaks. Prevention involves proper hand washing and disinfection of co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuberculosis
Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in which case it is known as latent tuberculosis. Around 10% of latent infections progress to active disease which, if left untreated, kill about half of those affected. Typical symptoms of active TB are chronic cough with blood-containing mucus, fever, night sweats, and weight loss. It was historically referred to as consumption due to the weight loss associated with the disease. Infection of other organs can cause a wide range of symptoms. Tuberculosis is spread from one person to the next through the air when people who have active TB in their lungs cough, spit, speak, or sneeze. People with Latent TB do not spread the disease. Active infection occurs more often in people with HIV/AIDS and in those who smoke. Diagnosis of active ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pneumonic Plague
Pneumonic plague is a severe lung infection caused by the bacterium ''Yersinia pestis''. Symptoms include fever, headache, shortness of breath, chest pain, and coughing. They typically start about three to seven days after exposure. It is one of three forms of plague, the other two being septicemic plague and bubonic plague. The pneumonic form may occur following an initial bubonic or septicemic plague infection. It may also result from breathing in airborne droplets from another person or animal infected with pneumonic plague. The difference between the forms of plague is the location of infection; in pneumonic plague the infection is in the lungs, in bubonic plague the lymph nodes, and in septicemic plague within the blood. Diagnosis is by testing the blood, sputum, or fluid from a lymph node. While vaccines are being developed, in most countries they are not yet commercially available. Prevention is by avoiding contact with infected rodents, people, or cats. It is recomm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pneumonic Plague
Pneumonic plague is a severe lung infection caused by the bacterium ''Yersinia pestis''. Symptoms include fever, headache, shortness of breath, chest pain, and coughing. They typically start about three to seven days after exposure. It is one of three forms of plague, the other two being septicemic plague and bubonic plague. The pneumonic form may occur following an initial bubonic or septicemic plague infection. It may also result from breathing in airborne droplets from another person or animal infected with pneumonic plague. The difference between the forms of plague is the location of infection; in pneumonic plague the infection is in the lungs, in bubonic plague the lymph nodes, and in septicemic plague within the blood. Diagnosis is by testing the blood, sputum, or fluid from a lymph node. While vaccines are being developed, in most countries they are not yet commercially available. Prevention is by avoiding contact with infected rodents, people, or cats. It is recomm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bubonic Plague
Bubonic plague is one of three types of plague caused by the plague bacterium ('' Yersinia pestis''). One to seven days after exposure to the bacteria, flu-like symptoms develop. These symptoms include fever, headaches, and vomiting, as well as swollen and painful lymph nodes occurring in the area closest to where the bacteria entered the skin. Acral necrosis, the dark discoloration of skin, is another symptom. Occasionally, swollen lymph nodes, known as " buboes," may break open. The three types of plague are the result of the route of infection: bubonic plague, septicemic plague, and pneumonic plague. Bubonic plague is mainly spread by infected fleas from small animals. It may also result from exposure to the body fluids from a dead plague-infected animal. Mammals such as rabbits, hares, and some cat species are susceptible to bubonic plague, and typically die upon contraction. In the bubonic form of plague, the bacteria enter through the skin through a flea bite a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Small Pox
Smallpox was an infectious disease caused by variola virus (often called smallpox virus) which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) certified the global eradication of the disease in 1980, making it the only human disease to be eradicated. The initial symptoms of the disease included fever and vomiting. This was followed by formation of ulcers in the mouth and a skin rash. Over a number of days, the skin rash turned into the characteristic fluid-filled blisters with a dent in the center. The bumps then scabbed over and fell off, leaving scars. The disease was spread between people or via contaminated objects. Prevention was achieved mainly through the smallpox vaccine. Once the disease had developed, certain antiviral medication may have helped. The risk of death was about 30%, with higher rates among babies. Often, those who survived had extensive scarring of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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