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A representation by Robert Seymour of the cholera epidemic depicts the spread of the disease in the form of poisonous air.. The miasma theory was the predominant theory of disease transmission before the germ theory took hold towards the end of the 19th century; it is no longer accepted as a correct explanation for disease by the scientific community.
Bacteria genera found in both air samples and the Antarctic include Staphylococcus, Bacillus, Corynebacterium, Micrococcus, Streptococcus, Neisseria, and Pseudomonas. [7] Bacteria were also found living in the cold and dark in a lake buried a half-mile deep (0.80 km) under the ice in Antarctica. [10] [11] [12]
Koch found that he could transmit anthrax from one animal to another by taking a small sample of blood from the infected animal and injecting it into a healthy one, and this caused the healthy animal to become sick. He also found that he could grow the bacteria in a nutrient broth, then inject it into a healthy animal, and cause illness.
Bacteria grow to a fixed size and then reproduce through binary fission, a form of asexual reproduction. [114] Under optimal conditions, bacteria can grow and divide extremely rapidly, and some bacterial populations can double as quickly as every 17 minutes. [115] In cell division, two identical clone daughter cells are produced. Some bacteria ...
The following outline is provided as an overview of and topical guide to concepts related to infectious diseases in humans.. Infection – transmission, entry/invasion after evading/overcoming defense, establishment, and replication of disease-causing microscopic organisms (pathogens) inside a host organism, and the reaction of host tissues to them and to the toxins they produce.
Humans can be infected with many types of pathogens, including prions, viruses, bacteria, and fungi, causing symptoms like sneezing, coughing, fever, vomiting, and potentially lethal organ failure. While some symptoms are caused by the pathogenic infection, others are caused by the immune system's efforts to kill the pathogen, such as ...
Phaeocystis is an important algal genus found as part of the marine phytoplankton around the world. It has a polymorphic life cycle, ranging from free-living cells to large colonies. [ 196 ] It has the ability to form floating colonies, where hundreds of cells are embedded in a gel matrix, which can increase massively in size during blooms ...
Access to the previously invisible world opened the eyes and the minds of the researchers of the seventeenth century. Antonie van Leeuwenhoek investigated diverse bacteria of various shapes, fungi, and protozoa, which he called animalcules, mainly from water, mud, and dental plaque samples, and discovered biofilms as a first indication of microorganisms interacting within complex communities.