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.
Whooping 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". The cough may be so hard that it causes vomiting, rib fractures, and fatigue. Children less than one year old may have little or no cough and instead have periods where they cannot breathe. The incubation period is usually seven to ten days. Disease may occur in those who have been vaccinated, but symptoms are typically milder.
An exotoxin is a toxin secreted by bacteria. An exotoxin can cause damage to the host by destroying cells or disrupting normal cellular metabolism. They are highly potent and can cause major damage to the host. Exotoxins may be secreted, or, similar to endotoxins, may be released during lysis of the cell. Gram negative pathogens may secrete outer membrane vesicles containing lipopolysaccharide endotoxin and some virulence proteins in the bounding membrane along with some other toxins as intra-vesicular contents, thus adding a previously unforeseen dimension to the well-known eukaryote process of membrane vesicle trafficking, which is quite active at the host–pathogen interface.
Bordetella bronchiseptica is a small, gram-negative, rod-shaped bacterium of the genus Bordetella. It can cause infectious bronchitis in dogs and other animals, but rarely infects humans. Closely related to B. pertussis—the obligate human pathogen that causes pertussis ; B. bronchiseptica can persist in the environment for extended periods.
Bordetella is a genus of small, Gram-negative, coccobacilli bacteria of the phylum Pseudomonadota. Bordetella species, with the exception of B. petrii, are obligate aerobes, as well as highly fastidious, or difficult to culture. All species can infect humans. The first three species to be described ; are sometimes referred to as the 'classical species'. Two of these are also motile.
Pertussis toxin (PT) is a protein-based AB5-type exotoxin produced by the bacterium Bordetella pertussis, which causes whooping cough. PT is involved in the colonization of the respiratory tract and the establishment of infection. Research suggests PT may have a therapeutic role in treating a number of common human ailments, including hypertension, viral infection, and autoimmunity.
Bartonellosis is an infectious disease produced by bacteria of the genus Bartonella. Bartonella species cause diseases such as Carrión's disease, trench fever, cat-scratch disease, bacillary angiomatosis, peliosis hepatis, chronic bacteremia, endocarditis, chronic lymphadenopathy, and neurological disorders.
Influenza C virus is the only species in the genus Gammainfluenzavirus, in the virus family Orthomyxoviridae, which like other influenza viruses, causes influenza.
Bordetella pertussis is a Gram-negative, aerobic, pathogenic, encapsulated coccobacillus bacterium of the genus Bordetella, and the causative agent of pertussis or whooping cough. Its virulence factors include pertussis toxin, adenylate cyclase toxin, filamentous hæmagglutinin, pertactin, fimbria, and tracheal cytotoxin.
Adenylate cyclase toxin is a virulence factor produced by some members of the genus Bordetella. Together with the pertussis toxin it is the most important virulence factor of the causative agent of whooping cough, Bordetella pertussis. Bordetella bronchiseptica and Bordetella parapertussis, also able to cause pertussis-like symptoms, also produce adenylate cyclase toxin. It is a toxin secreted by the bacteria to influence the host immune system.
A subclinical infection—sometimes called a preinfection or inapparent infection—is an infection by a pathogen that causes few or no signs or symptoms of infection in the host. Subclinical infections can occur in both humans and animals. Depending on the pathogen, which can be a virus or intestinal parasite, the host may be infectious and able to transmit the pathogen without ever developing symptoms; such a host is called an asymptomatic carrier. Many pathogens, including HIV, typhoid fever, and coronaviruses such as COVID-19 spread in their host populations through subclinical infection.
Sporothrix schenckii, a fungus that can be found worldwide in the environment, is named for medical student Benjamin Schenck, who in 1896 was the first to isolate it from a human specimen. The species is present in soil as well as in and on living and decomposing plant material such as peat moss. It can infect humans as well as animals and is the causative agent of sporotrichosis, commonly known as "rose handler's disease." The most common route of infection is the introduction of spores to the body through a cut or puncture wound in the skin. Infection commonly occurs in otherwise healthy individuals but is rarely life-threatening and can be treated with antifungals. In the environment it is found growing as filamentous hyphae. In host tissue it is found as a yeast. The transition between the hyphal and yeast forms is temperature dependent making S. schenckii a thermally dimorphic fungus.
The AB5 toxins are six-component protein complexes secreted by certain pathogenic bacteria known to cause human diseases such as cholera, dysentery, and hemolytic–uremic syndrome. One component is known as the A subunit, and the remaining five components are B subunits. All of these toxins share a similar structure and mechanism for entering targeted host cells. The B subunit is responsible for binding to receptors to open up a pathway for the A subunit to enter the cell. The A subunit is then able to use its catalytic machinery to take over the host cell's regular functions.
Visna-maedi virus from the genus Lentivirus and subfamily Orthoretrovirinae, is a retrovirus that causes encephalitis and chronic pneumonitis in sheep. It is known as visna when found in the brain, and maedi when infecting the lungs. Lifelong, persistent infections in sheep occur in the lungs, lymph nodes, spleen, joints, central nervous system, and mammary glands; The condition is sometimes known as ovine progressive pneumonia (OPP), particularly in the United States, or Montana sheep disease. White blood cells of the monocyte/macrophage lineage are the main target of the virus.
Pneumococcal infection is an infection caused by the bacterium Streptococcus pneumoniae.
Microbial toxins are toxins produced by micro-organisms, including bacteria, fungi, protozoa, dinoflagellates, and viruses. Many microbial toxins promote infection and disease by directly damaging host tissues and by disabling the immune system. Endotoxins most commonly refer to the lipopolysaccharide (LPS) or lipooligosaccharide (LOS) that are in the outer plasma membrane of Gram-negative bacteria. The botulinum toxin, which is primarily produced by Clostridium botulinum and less frequently by other Clostridium species, is the most toxic substance known in the world. However, microbial toxins also have important uses in medical science and research. Currently, new methods of detecting bacterial toxins are being developed to better isolate and understand these toxins. Potential applications of toxin research include combating microbial virulence, the development of novel anticancer drugs and other medicines, and the use of toxins as tools in neurobiology and cellular biology.
A neutralizing antibody (NAb) is an antibody that defends a cell from a pathogen or infectious particle by neutralizing any effect it has biologically. Neutralization renders the particle no longer infectious or pathogenic. Neutralizing antibodies are part of the humoral response of the adaptive immune system against viruses, intracellular bacteria and microbial toxin. By binding specifically to surface structures (antigen) on an infectious particle, neutralizing antibodies prevent the particle from interacting with its host cells it might infect and destroy.
Tracheal cytotoxin (TCT) is a 921 dalton glycopeptide released by Bordetella pertussis, Vibrio fischeri, and Neisseria gonorrhoeae. It is a soluble piece of peptidoglycan (PGN) found in the cell wall of all gram-negative bacteria, but only some bacteria species release TCT due to inability to recycle this piece of anhydromuropeptide.
Bordetella avium is a gram negative, nonfermentative, strictly aerobic, motile bacterium from the genus Bordetella which has been isolated from patients with respiratory disease. B. avium has a global distribution, that mainly affects young domesticated turkeys. The disease in birds is called bordetellosis, and is largely associated with confined spaces and multi-aged flocks where management practices are sub optimal. In most infections, mortality is typically low but morbidity is very high.
Vaccine resistance is the evolutionary adaptation of pathogens to infect and spread through vaccinated individuals, analogous to antimicrobial resistance. It concerns both human and animal vaccines. Although the emergence of a number of vaccine resistant pathogens has been well documented, this phenomenon is nevertheless much more rare and less of a concern than antimicrobial resistance.
