Encephalitozoon cuniculi

Encephalitozoon cuniculi ( formerly known as Nosema cuniculi ) is an obligate intracellular living in the kidney, brain and other organs of parasitic protozoa. It is attributed to the microsporidia, the exact systematic position of this parasite has not yet, however, finally resolved. He is the agent of Encephalitozoonose, one occurring mainly in rabbits Altweltmäusen and canids disease that can be transmitted to people with an immune deficiency.

Classification

Encephalitozoon cuniculi is now divided into three serologically distinct strains. Morphologically, these three variants are indistinguishable. They shall be designated as Type I to III or according to their main host. For rabbits, all three strains are pathogenic.

Encephalitozoon cuniculi type I (rabbit strain) arrives in Europe especially in domestic rabbits frequently. He is also pathogenic for humans, while dogs against this strain probably are resistant.

Encephalitozoon cuniculi type II ( mouse strain ) is pathogenic for Altweltmäuse. In Scandinavia fatal infections in farm foxes were observed. In cats, it is particularly important to eye infections ( phakoklastische uveitis, focal lens opacification, anterior uveitis ).

Encephalitozoon cuniculi type III (dog strain) is widespread in North America and South Africa and mainly affects dogs. In European zoos infections in prosimians were observed.

Morphology

Encephalitozoon cuniculi was raised in histological preparations than about 2-2.5 × 0.8-1.2 microns wide, slightly curved rods with rounded ends dar. The pathogen are some cell organelles, such as mitochondria. The genome is extremely small at 2.9 Mbp and about 2000 code sequences.

Outside the host cells of the pathogen is as infectious stage duration in the form of a spore. The approximately 2 microns large spores consist of an outer ( Exospore ) and a thicker, chitin-rich inner layer ( endospore ). In the cytoplasm of the spore ( sporoplasm ) is a spirally rolled pile thread.

Development cycle

The host infection via spores. Encephalitozoon cuniculi has a mode of infection occurring only in microsporidia: The pile thread is everted, penetrates the cell membrane and injects the sporoplasm into the host cell. Approximately 10 times more likely, however, the spore passes through ordinary phagocytosis in a macrophage ( macrophage ). Then everted as a sign of germination of the spore only within the macrophage of the pile thread, which prevents the development of phagosomes in lysosomes and thus their degradation.

In the cytoplasm of the host cell, there is a multiple asexual reproduction ( merogony ) and finally to the formation of spores. You can use up to 100 sporoblasts occur per cell. The nature of the pathogen spread in the host is not yet precisely known. The pathogen mainly affects the kidneys and the brain. The excretion of the infectious spores via the urine.

The spores are very environmentally resistant. At 25 ° C they are three weeks at 10 ° C three months infectious. At 100 ° C they are inactivated after 5 minutes. For disinfection is boiling water, 2% Lysol, 1 % formaldehyde or 70 % are alcohol strength.