![Arthroconidia of Coccidioides immitis 39G0040 lores](https://upload.wikimedia.org/wikipedia/commons/c/c5/Arthroconidia_of_Coccidioides_immitis_39G0040_lores.jpg)
Arthroconidia are a type of
fungal
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from th ...
spore
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...
typically produced by segmentation of pre-existing fungal
hyphae
A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium.
Structure
A hypha consists of one or ...
.
Background
These spores are
asexual and are generally not as durable and environmentally persistent as, for instance,
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
l
endospore
An endospore is a dormant, tough, and non-reproductive structure produced by some bacteria in the phylum Bacillota. The name "endospore" is suggestive of a spore or seed-like form (''endo'' means 'within'), but it is not a true spore (i.e., no ...
s or
chlamydospore
A chlamydospore is the thick-walled large resting spore of several kinds of fungi, including Ascomycota such as '' Candida'', Basidiomycota such as ''Panus'', and various Mortierellales species. It is the life-stage which survives in unfavourable c ...
s. Some medically significant pathogens, such as ''
Coccidioides immitis
''Coccidioides immitis'' is a pathogenic fungus that resides in the soil in certain parts of the southwestern United States, northern Mexico, and a few other areas in the Western Hemisphere.
Epidemiology
''C. immitis'', along with its relati ...
'', and ''
Coccidioides posadasii
''Coccidioides posadasii'' is a pathogenic fungus that, along with ''Coccidioides immitis'', is the causative agent of coccidioidomycosis, or valley fever in humans. It resides in the soil in certain parts of the Southwestern United States, no ...
'', both causative agents of
coccidioidomycosis
Coccidioidomycosis (, ), commonly known as cocci, Valley fever, as well as California fever, desert rheumatism, or San Joaquin Valley fever, is a mammalian fungal disease caused by '' Coccidioides immitis'' or ''Coccidioides posadasii''. Coccid ...
(also known as San Joaquin Valley fever), are transmitted through airborne arthroconidia.
The small size of the arthroconidia, 3 to 5
µm, allow them to lodge themselves into the terminal
bronchiole
The bronchioles or bronchioli (pronounced ''bron-kee-oh-lee'') are the smaller branches of the bronchial airways in the lower respiratory tract. They include the terminal bronchioles, and finally the respiratory bronchioles that mark the start o ...
s of the lung. There, they develop into a thick-walled
spherule
A sphere () is a geometrical object that is a three-dimensional analogue to a two-dimensional circle. A sphere is the set of points that are all at the same distance from a given point in three-dimensional space.. That given point is the ...
filled with endospores that cause a pyogenic (pus-causing) inflammation.
See also
*
Conidium
A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to th ...
References
Fungal morphology and anatomy
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