the specimen tends to take 3 to 6 days to form a pinpoint sized colony. B. pertussis appears to only affect the human species, therefore identifying humans as its only host and reservoir. It has multiple virulence factors that allow it to be an aggressive pathogen. B. pertussis has several virulence factors, mainly involving proteins that have been separated into 2 main classifications: adhesions and toxins. The adhesions category consists of the following: filamentous hemagglutinin (FHA), fimbriae
Parasites and their Virulence Why do some parasites kill the host they depend upon while others coexist with their host? Two prime factors determine parasitic virulence: the manner in which the parasite is transmitted, and the evolutionary history of the parasite and its host. Parasites which have colonized a new host species tend to be more virulent than parasites which have coevolved with their hosts. Parasites which are transmitted horizontally tend to be more virulent than those transmitted
Optimal virulence is a long-term evolutionary strategies adopted by pathogen to maximize its persistence within a host population. Optimal virulence suggested the relationship between host and parasites in ecosystem. The parasite's fitness is measure by how effective it is in transmitting offspring to hosts. Virulence is considered by most biologists to be an unavoidable consequence of host resource exploitation (Dybdahl and Storfer, 2003). In order to live longer in a host body a pathogen should
host or the studied parasite is sexually transmitted it would not benefit the parasite to decrease mating success of the host by limiting expression of certain traits or increasing virulence (Luong and Kaya 2005). There may be many other aspects of the host- parasite relationship that could be important in parasite virulence and degree of expression of secondary sexual characteristics. For the purpose of this study parasite life cycle and mode of transmission will be further examined using previous empirical
3. Imagine that a new medical treatment completely removes any negative effects of being a heterozygote for the mutant allele that cause Huntington’s disease; however, homozygotes for the defective alleles still develop the disease with its normal consequences. Assume everyone who needs it is able to get this treatment. How would you expect the frequencies of the Huntington’s allele and the disease itself to change over a long period following the introduction of this treatment. Huntington’s disease
Aquaculture is the fastest growing food producing sector and plays an important role in the global economic growth. Aquaculture is not only a source of food but it is also one of the main sources of income of millions of people around the world. The percentage of people engaged in the aquaculture sector in 2006 was 3.2% of the 1.37 billion people who are economically active in agriculture. Therefore, the sustainable development of aquaculture is of utmost importance for the food security and equally
SpeB expression is once again downregulated as the bacterium invades the bloodstream. GAS selects for mutations in the CovRS regulatory system, which result in reduced expression of SpeB and a simultaneous enhancement of the production of another virulence factor, Sda1. Sda1 helps avoid host neutrophil extracellular traps, allowing the bacterium to survive in the bloodstream and produce the bacteremia and sepsis characteristic of invasive GAS infections (26).
as bacteria or viruses that live inside of our cells have had a major influence upon our evolution (Parks, Panelli & Weinstein, 2003). Pathogens have affected our evolution in two major ways, which I will focus on: antibiotic resistance and virulence. Virulence has also changed in regards to ways of reproduction and establishing a higher rate of fitness. Other than pathogens, the human body has evolved to develop processes in which the cells are better protected (Parks, Panelli & Weinstein, 2003)
a radical approach that considers why evolution has not “freed” humans from disease. Traditional medicine, for example, would examine who contracted a cold, why, and how to treat the symptoms. Evolutionary medicine examines the interplay between virulence, transmission, natural selection, and evolution in an attempt to understand why anyone would catch a cold. This presents a potent example. With a pathogen like a cold, generation time is short, mutation rates are high, and genetic information can
and spontaneous bacterial peritonitis (WHO Pneumonia factsheet, 2013). The main aim of this paper is to familiarize the reader with Streptococcus pneumoniae and one particular disease that it causes - pneumonia. Taxonomy, morphology, physiology, virulence factors of Streptococcus pneumoniae Streptococcus pneumoniae is a bacterium, which has the following lineage: Firmicutes; Bacilli; Lactobacillales; Streptococcaceae; Streptococcus; Streptococcus pneumoniae (NCBI database taxonomy, 2001). Streptococcus
Pasteurella multocida was first isolated in 1880 by Louis Pasteur, and was described as the causative agent of fowl cholera.(1,2) During this time in history, microorganism isolated from livestock suffering from conditions such as haemorrhagic septicemia and atrophic rhinitis who demonstrated similar biochemical and morphological characteristics to that of Pasteurs’ microorganism where named Pasteurella septica.(1,3) It was not until the 1930s, when scientist recognised that the bacterium was associated
History Francisella tularensis is a bacteria that is commonly referred to as Rabbit Fever. This microorganism is often known as this because the bacteria resides in mammals such as rabbits, squirrels and mice (UPMC Center for Health Security, 2013). There are many different components to this bacteria that make it unique. The microorganism F. tularensis is one that has very unique characteristics that make it responsible for being the kind of bacteria that it is. It is a gram-negative bacteria
Hepatitis B virus (HBV) is a severe and common virus that has infected ‘more than two billion people alive today at some point in their life.’1 It is a hepadanavirus that interferes with the liver functions as it replicates in the hepatocytes (liver cells) and induces a immune response that is responsible for the inflammation of liver.2 Viruses are not motile, which means that HBV is also sessile and does not form spores. The spherical virion, is called a Dane Particle3 that is 42nm in diameter binds
the bacterial communication system mvfR, which is essential to the full virulence of P. aeruginosa. MvfR binds to and activates the pqs operon, which encodes for the synthesis of PQS, HHQ and 2-AA. Both PQS and HHQ bind to and activate mvfR, which leads to the production of mvfR virulence factors that promote acute and persistent infections. By identifying quorum sensing inhibitors, they were able to inhibit the mvfR virulence regulon, which disrupted cell-to-cell communication and limited P. aeruginosa
Escherichia coli strains are capable of causing three common clinical diseases that include sepsis/meningitis, urinary tract infection and enteric diarrhea disease. The pathogenic E. coli is known to be highly diverse, adaptable and contain various virulence factors that affect a wide range of cellular processes. Therefore, pathogenic Escherichia coli is studied extensively in food, mammals, and the environment. Outbreaks of diseases associated with E. coli are common in developed and developing countries
epithelium and the human hosts simply remain carriers, whereas in others, it can cause invasive meningococcal disease [5]. Different virulence factors are responsible for the pathogenesis of meningococcal disease. The bacterium expresses various cell surface and secreted virulence factors which allows it to colonize and infect the host cells. A number of such virulence factors include the autotransporters [3, 6]. Autotransporters which are secreted via type ⋁ secretion system, currently represent the
they are the least harmful in a few cases, but still can cause some troubles along the way. Enhanced Pathogens are used to provide vital insights while treating the viruses. Although, when they are used to increase mammalian transmissibility and virulence, the altered viruses pose serious Biosafety risks. Even though it can insure preparedness for the public in case of an outbreak of any such pandemic diseases, like in case of Ebola, MERS, SARS., Enhanced Pathogens is a huge Biosafety risk to society
antibodies for a specific disease so that next time when a real infection comes along your body is prepared for the infection which in turn aids in antibody resistance. Biotechnology has provided tools for understanding virulence which is the capacity of a microorganism to cause disease (virulence meaning: Collins English Dictionary 2014) and how microbial immunogens function and secondly it offers new ways for creating vaccines (Fields and Chanock, 1989). Vaccines were first invented by Edward Jenner in
According to the World Health Organization (WHO), approximately five million people will become ill by one or more of these four sexually transmitted infections (STI) each year; chlamydia, gonorrhea, syphilis, and trichomoniasis.1 Out of these four, gonorrhea has become increasingly drug resistant which causes a major threat to attempts to decrease STI’s. 1 This disease is also known to have a high prevalence and low mortality within our society.1 Individuals living with gonorrhea will also have
cells require 45 minutes to 4 hours to mount an inflammatory response (8). A diagram outlining S. flexneri's type three secretion system can be viewed at: http://www.grad.ucl.ac.uk/comp/2003/jointposter/gallery/index.pht?entryID=29 Virulence: A 214-kb virulence plasmid encodes for S. flexneri's entry into human epithelial cells and intra-intercellular movement (6). Once in contact with the target cell, Ipa proteins (IpaB, IpaC and Ipa D) encode for a specific type III secretion system, thus