Legionella infection; an environmental and clinical study during hajj season

ABSTRACT

Respiratory system is most commonly affected during Hajj season. [1] to determine the prevalence of Legionella in drinking water, cooling sprinklers and other sources of water consumed in pilgrimage area of the holy city, Makkah; [2] to study the prevalence of pneumonia caused by Legionella species from clinically suspected cases; and [3] to determine whether there is any relationship disease incidence and water supply system. The clinical samples were received from in-patients of the following five Ministry of Health [MOH] Hospitals; Hera General Hospital, Al-Noor Specialist Hospital, King Faisal Hospital, King Abdul-Aziz Hospital, and Ajyad Hospital during Hajj 2003. The patients included in the study were those who fulfilled the following criteria; clinically diagnosed as pneumonia, negative on routine cultures and found negative for acid fast bacilli [AFB] from sputum/bronchial aspirate [BAL]. Serological tests was done by Enzyme linked Immunosorbent assay [ELISA] for Legionella antibodies total lgG and IgM. Out of total 133 patients suspected for Legionella, 83 [62.4%] were male and 50 [37.6%] female. The male versus female ratio was 10.6. The major age group affected was between 50-70 years [63.2%]. There were 4 [3.0%] cases of Legionella species isolated from microbiological cultures. The overall seropositive rate among clinically suspected cases was 4.51%. A total of 560 water samples were collected from Arafat, Muzdalifa, Mena, and areas around the Holy Mosque and found negative for Legionella species. Pneumonia was one of the most common illnesses among pilgrims. The water supplied to all areas of the pilgrimage was free from the Legionella and no link has been established among the patients with water supply systems. Both clinicians' awareness and availability of specialized laboratory tests for atypical pneumonia such as Legionella is necessary. Although, all water samples found negative for Legionella but it is recommended to screen all water reservoirs for Legionella annually before Hajj season