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Updated: Jan 6, 2026

Composition and Distribution Analysis of Bioaerosols Under Different Environmental Conditions
Published on: January 7, 2019
Environmental investigation of respiratory pathogens during the Hajj 2016 and 2018
Van-Thuan Hoang1, Doudou Sow2, Khadidja Belhouchat3
1Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France; IHU-Méditerranée Infection, Marseille, France; Thai Binh University of Medicine and Pharmacy, Thai Binh, Viet Nam.
Background:
Respiratory tract infections are common in the context of the Hajj pilgrimage and respiratory pathogens can be transmitted via contact with contaminated surfaces. We sampled surfaces during the Hajj to detect the presence of respiratory bacteria and viruses.
Methods:
Frequently touched surfaces at Mecca, Mina, Arafat and Medina were sampled. The common respiratory pathogens were tested by qPCR.
Results:
70/142 (49.3%) environmental samples collected were positive for at least one respiratory pathogen. Among the positive samples, Klebsiella pneumoniae was the bacterium most frequently tested positive (57.1%), followed by Streptococcus pneumoniae (12.9%), Staphylococcus aureus (10.0%) and Haemophilus influenzae (7.1%). 32.9% positive samples tested positive for rhinovirus and 1.4% for coronavirus. Surfaces with the highest rates of positive samples were kitchen tables (100%), water fountain faucet (73.3%) and edge of water coolers lid (84.6%). Samples collected in Mina were the most frequently contaminated with 68.8% being positive for at least one pathogen and 18.8% positive for a combination of multiple pathogens.
Conclusion:
These preliminary results indicate that respiratory pathogens are common in environmental surfaces from areas frequented by Hajj pilgrims. Further larger-scale studies are needed to better assess the possible role of environmental respiratory pathogens in respiratory infections in Hajj pilgrims.
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