Microbial surveillance of Hajj tents: Bioaerosol sampling coupled with real-time multiplex PCR


      • Hajj tent environment may contribute to the spread of airborne infections during Hajj.
      • Important in determining the risks and contribution of the Hajj tent environment to pilgrim health.
      • Cross transmission that could progress to infection.
      • Performing microbial surveillance during Hajj.
      • Prevent outbreaks and provide cautionary information related to possible future epidemics.


      Respiratory tract infections are common among pilgrims attending annual Hajj in Mecca, Saudi Arabia. Pilgrims typically spend most of the Hajj period inside ventilated tents, where microorganisms may be transmitted through bioaerosols and droplets.


      To perform microorganism surveillance inside Hajj tents and assess the similarities between microorganisms isolated from tent bioaerosol samples and nasopharyngeal swabs (NP) of tent occupants.


      Respiratory microorganisms in bioaerosols collected from Hajj tents over a 4-day period were compared with NP of tent occupants using real-time multiplex polymerase chain reaction analysis.


      A total of 152 samples were collected: 120 tent bioaerosol samples collected on days 9, 10, 11, and 12 of Dhu al-Hijjah, and 32 NP collected on day 12 of Dhu al-Hijjah (corresponding to 23/08/2018). Eighty-three (69.2%) bioaerosol samples tested positive for at least 1 microorganism, with the number of pathogens increasing over the 4 days of sampling. Twenty-seven (84.38%) NP swabs from tent occupants also tested positive. Microorganisms identified in pilgrim nasal carriage and tent bioaerosol samples were similar, and included K. pneumonia, S. aureus, S. pneumonia, human adenovirus, Moraxella, influenza A, and H. influenza.


      The data suggest that the Hajj tent environment may contribute to the spread of airborne infections during Hajj. This can have important ramifications for novel pathogens with pandemic potential.

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