Abstract
Background and Aims:
Sandstorms in arid regions pose health risks owing to the presence of microbial dust particles. While microbial dust has been studied, the free-living parasite Acanthamoeba, found in air, water, and dust causing infections like Acanthamoeba keratitis and rare encephalitis, has not been investigated. This study aims to isolate and identify Acanthamoeba species from indoor and outdoor dust samples collected during sandstorm events at Majmaah University.

Methods:
In this study, a novel passive air sampling method was used with sterile aluminium foil plate containers with electrostatic dust cloth devices for outdoor samples and swab techniques for indoor samples. Samples were collected from various locations, including classrooms and laboratories. Standard microbiological techniques were applied, with samples inoculated onto non-nutrient agar with E. coli culture and incubated at 30°C for 14 days. Acanthamoeba species were identified through microscopic observation.

Results:
Out of 108 analyzed samples, outdoor environments had a higher Acanthamoeba positivity rate (75.0%) compared to indoor samples (44.6%). The highest positivity rates in outdoor sites were found in car parking areas (81.8%), exterior college tables (75.0%), and residential area air samples (73.3%). Indoor locations showed varied results, with lab corridors (62.5%) and areas near lab windows (58.3%) having higher detection rates.

Conclusion:
This pioneering study is the first to investigate Acanthamoeba in sandstorm dust, revealing a 75.4% positivity rate in outdoor environments. The findings highlight the need for increased awareness and preventive measures, especially for vulnerable populations, and call for comprehensive research across desert regions.

Key words: Acanthamoeba species, Sandstorm, dust, Non nutrient agar, Trophozoites, Cysts