Language
Country/Area
No result found
How does Acanthamoeba cross the blood-brain barrier? What is the mysterious mechanism?
Acanthamoeba is an amoeba commonly found in soil, freshwater and other habitats. It has two main life stages: a metabolically active trophozoite stage and a stress-tolerant dormant vesicle stage. While these amoebas are typically free-living fungivores, they can also act as opportunistic pathogens, causing serious and sometimes fatal infections, especially in people with weakened immune systems.
The disease does not occur by chance; Acanthamoeba's biological properties allow it to worsen in the human body.
Distribution of Acanthamoeba
Acanthamoeba spp. is one of the most common protozoa in the environment. Its distribution range includes soil, air, sewage, seawater, chlorinated swimming pools, household tap water, bottled water and other environments. In addition, these amoeba are also found on human skin, nose, throat and intestines, and can also infect plants and other mammals.
Impact on disease
Major diseases caused by Acanthamoeba include keratitis and granular amoebic encephalitis (GAE). The latter usually occurs in immunosuppressed patients. GAE is a serious infection caused by amoeba entering the body through a wound in the skin and spreading to the brain through the blood.
When the host's immune response combines with the protease secreted by the amoeba, it will cause severe swelling of the brain, which may cause the death rate of the infected person to be as high as 95%.
Granular amoebic encephalitis (GAE)
GAE affects the central nervous system, with symptoms including headaches, epilepsy, and changes in mental status. These symptoms become more severe over time and eventually lead to death in most patients. Infections are often associated with conditions such as immunodeficiency, diabetes, malignancy, malnutrition, systemic lupus erythematosus, and alcoholism.
The specific mechanism by which Acanthamoeba can cross the blood-brain barrier is currently unclear, but as it invades connective tissue and induces a pro-inflammatory response, it will cause neuronal damage and may be fatal.
Studies have shown that pure granular lesions in the brain are rare in patients with AIDS and other related immune deficiencies because they have insufficient numbers of CD+ T cells to respond appropriately to Acanthamoeba infection.
Diagnosis and treatment of infection
Due to the rarity and lack of knowledge about this parasite, there is currently no effective diagnosis or treatment. Existing treatment options, such as amphotericin B, rifampin, and combined sulfamethoxazole, have limited effectiveness. However, an article published in 2013 showed that some FDA-approved drugs had a bactericidal rate of more than 90% in in vitro tests, providing hope for possible future human trials.
Acanthamoebic keratitis
When Acanthamoeba is present in the eye, it will cause keratitis, which may lead to corneal ulcers or blindness. This condition is most common in people who do not disinfect contact lenses properly.
Multi-purpose contact lens solutions are not effective against Acanthamoeba, so it is recommended to use a hydrogen peroxide-based solution for disinfection.
Ecology of Acanthamoeba
Acanthamoeba can be found in a variety of soil ecosystems. Past research has shown that it has predatory behavior on bacteria, fungi and other protozoa, and may play an important role in the decomposition of organic matter.
With in-depth research on Acanthamoeba, scientists have discovered its potential application value in fields such as cell biology and environmental biology.
Stress-tolerant organisms, bacterial reservoirs in the environment, and host properties as pathogens make Acanthamoeba a model organism in scientific research. Faced with these mechanisms and effects, we can't help but wonder, can we further our understanding of this tiny organism in the future to prevent the health risks it brings?
