Search results
Results from the WOW.Com Content Network
An obligate parasite or holoparasite is a parasitic organism that cannot complete its life-cycle without exploiting a suitable host. If an obligate parasite cannot obtain a host it will fail to reproduce. This is opposed to a facultative parasite, which can act as a parasite but does not rely on its host to continue its life-cycle.
Examples of obligate intracellular bacteria include Rickettsia prowazekii and Rickettsia rickettsii, (Rocky Mountain spotted fever). [citation needed] Chlamydia are intracellular parasites. These pathogens can cause pneumonia or urinary tract infection and may be involved in coronary heart disease. [12]
Study of obligate pathogens is difficult because they cannot usually be reproduced outside the host. However, in 2009 scientists reported a technique allowing the Q-fever pathogen Coxiella burnetii to grow in an axenic culture and suggested the technique may be useful for study of other pathogens. [19]
Unlike facultative intracellular bacteria that can grow within or outside of a host's body, obligate bacteria cannot survive without host cells. These bacteria cannot reproduce outside of the host cell because they lack the metabolic processes and enzymes needed to reproduce, which the host cell gives them. [ 3 ]
One example of a potent fungal animal pathogen are Microsporidia - obligate intracellular parasitic fungi that largely affect insects, but may also affect vertebrates including humans, causing the intestinal infection microsporidiosis. [77] Borrelia burgdorferi, the bacterium that causes Lyme disease, is transmitted by Ixodes ticks.
An obligate human pathogen, it primarily colonizes the mucosal lining of the urogenital tract; however, it is also capable of adhering to the mucosa of the nose, [4] pharynx, rectum, and conjunctiva. [5]
Without this process in place, the pathogen may not survive long enough in the vector to properly replicate and infect other hosts. [20] R. rickettsii is an obligate intracellular alpha proteobacterium that belongs to the Rickettsiacaea family. Within the Rickettsia species, these bacteria are divided into four clades.
Coxiella burnetii is an obligate intracellular bacterial pathogen, and is the causative agent of Q fever. [1] The genus Coxiella is morphologically similar to Rickettsia, but with a variety of genetic and physiological differences.