Occurrence and quantitative microbial risk assessment of Cryptosporidium and Giardia in soil and air samples

Type Journal Article - International Journal of Infectious Diseases
Title Occurrence and quantitative microbial risk assessment of Cryptosporidium and Giardia in soil and air samples
Author(s)
Volume 26
Publication (Day/Month/Year) 2014
Page numbers 123-127
URL http://europepmc.org/abstract/med/25043458
Abstract
Background

Cryptosporidium oocysts and Giardia cysts can be transmitted by the fecal–oral route and may cause gastrointestinal parasitic zoonoses. These zoonoses are common in rural zones due to the parasites being harbored in fecally contaminated soil. This study assessed the risk of illness (giardiasis and cryptosporidiosis) from inhaling and/or ingesting soil and/or airborne dust in Potam, Mexico.

Methods

To assess the risk of infection, Quantitative Microbial Risk Assessment (QMRA) was employed, with the following steps: (1) hazard identification, (2) hazard exposure, (3) dose–response, and (4) risk characterization.

Results

Cryptosporidium oocysts and Giardia cysts were observed in 52% and 57%, respectively, of total soil samples (n = 21), and in 60% and 80%, respectively, of air samples (n = 12). The calculated annual risks were higher than 9.9 × 10-1 for both parasites in both types of sample.

Conclusions

Soil and air inhalation and/or ingestion are important vehicles for these parasites. To our knowledge, the results obtained in the present study represent the first QMRAs for cryptosporidiosis and giardiasis due to soil and air inhalation/ingestion in Mexico. In addition, this is the first evidence of the microbial air quality around these parasites in rural zones.

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