Encephalitozoon cuniculi (Encephalitozoonosis) - Molecular diagnosis (PCR)
Encephalitozoon cuniculi is an obligate intracellular microorganism belonging to the phylum Microsporida, Encephalitozoon gender, family Unikaryonidae, with a worldwide distribution. Currently for phylogenetic studies it is considered a hong with an ancestor in Zygomycotina. This parasite affects animals such as mice and rabbits, monkeys, dogs, rats, birds, guinea pigs and other mammals, including people. Encephalitozoon cuniculi infection causes a disease called encephalitozoonosis, which mainly affects rabbits, but not exclusively.
The life cycle of this organism involves a host where it matures and multiplies. The infectious form of Encephalitozoon cuniculi is resistant spore can survive for a long time in the environment. Spores are uninucleate, with a size of 2 to 4 .mu.m .mu.m x 1 to 1.5 with a polar tubule with 5 to 7 arranged in a row around. Once in the host organism, spore infectious sporoplasm injected into the eukaryotic host cell through the polar tubule. Inside the cell, the sporoplasm multiplied either by binary fission or multiple fission. Microsporidia develop by Sporogony to mature spores in the cytoplasm or inside the parasitophorous vacuole. During sporogony, a thick wall around the spore, which provides resistance to adverse environmental conditions is formed. Once spores increase in number and completely colonize the cytoplasm of the host cells, the cell membrane ruptures and releases spores around them. These free mature spores can infect new cells, continuing the cycle.
Encephalitozoon cuniculi transmission occurs through ingestion or inhalation of spores present in secretions or body exudates and transplacental.
In animals, Encephalitozoon cuniculi infection can lead to different clinical pictures depending on the affected organ, although in most cases affects jointly or isolated to the kidneys, eyes and brain. In the kidney, infection usually is asymptomatic, but can cause granuloma development that may lead to a chronic mild renal impairment with problems such as increased thirst and weight loss. In the eye, infection causes lesions in the lens, causing phacoclastic uvetitis, wherein the parasite injures the outer membrane of the lens, releasing the contents thereof, which damages the surrounding structures and can cause loss of vision. When the microorganism infects the nervous system manifestations associated include seizures, tremors, torticollis, ataxia, urinary incontinence, loss of balance and paralysis.
In humans, infection Encephalitozoon cuniculi usually causes minimal damage. In immunocompromised individuals as people with HIV coursing mainly with involvement of the nervous system, while it may cause diarrhea, sinusitis, keratoconjunctivitis, nephritis and hepatitis. In immunosuppressed individuals may present with disseminated infection and disease can be fatal. In immunosuppressed patients (HIV infected or transplanted) plus Encephalitozoon cuniculi, found other species like Encephalitozoon intestinalis, and Encephalitozoon Hellen. In these patients can cause severe diarrhea, in which case they can be found in feces.
Recommended tests for diagnosis:
The diagnosis is based on microscopic identification, antibody detection, or molecular diagnostic methods (PCR). Molecular methods (PCR), offer the advantage of providing a quick and specific diagnosis.
The diagnosis has been based on a combination of signs of neurological deficits detection of spores in affected tissues, or stool stained with fluorescent dyes, with high antibody titers. Histopathology has been the standard diagnostic method using immunohistochemical methods for diagnosis of granulomatous encephalitis with interstitial nephritis.
It is important difetrenciar Encephalitozoon of Enterocytozoon because the treatments are different (Encephalitozoon can be treated with albendazole and Enterocytozoon with fumagillin).
For these reasons, molecular methods (PCR) are currently recommended.
Tests in IVAMI:
- Molecular diagnosis (PCR), to detect DNA Encephalitozoon cuniculi.
- Urine sample (10 mL).
- Current transition stool (10 g).
- Sample of affected tissue.
Preservation and shipment of sample:
- Refrigerated (preferred) for less than 2 days.
- Frozen: over 2 days (for molecular diagnostic tests only).
- Molecular diagnosis (PCR): 24 to 48 hours.
Cost of the test: