Journalof Infection (1998) 36, 303-306 Tuberculosis is the Commonest Cause of Pneumonia Requiring Hospitalization During Hajj (Pilgrimage to Makkah) A. Alzeer .1, A. Mashlah 2, N. Fakim 3, N. AI-Sugair a, M. AI-Hedaithy 1, S. AI-Majed 1 and G. Jamjoom ~ 1Department of Medicine, 4Department of Microbiology, King Saud University, Riyadh, 2King Abdulaziz Hospital, Makkah, 3A1-Noor Specialist Hospital, Makkah, SChest Hospital, Taif, Saudi Arabia The diagnosis and treatment of pneumonia in mass gathering situations is a medical challenge, requiring prompt decision making and knowledge of the aetiology. We studied cases of pneumonia admitted to two hospitals during the 1994 pilgrimage (Hail) season to Makkah. Sixty-four patients were enrolled in the study, of which 47 (75%) were men with a mean age of 63 years (range 21-91). Nearly all were from developing countries. Diagnosis was established in 46 patients (72%) with Mgcobacterium tuberculosis being the commonest causative organism (20%), followed by Gram-negative bacilli (18.8%). Streptococcus pneumoniae accounted for only 10%, with Legionella pneumophilia, Mycoplasma pneu- moniae, and viruses accounting each for 6%. The main finding of this study is that M. tuberculosis is a common cause of pneumonia under these unusual "extreme circumstances". Its presentation was acute and indistinguishable from pyogenic pneumonia. Thirty-one per cent of tuberculous cases had upper lobe involvement, 54% lower lobe, and 15% multi-lobar. This was similar to the radiographic features in non-tuberculous pneumonia cases. All but one patient with tuberculosis recovered following the administration of first-line anti-tuberculous drugs. The total mortality was 17%. The preponderance of M. tuberculosis and Gram-negative bacteria over S. pneumoniae may reflect the prior use of amoxyciflin and the effect of exhaustion, malnutrition, and old age. Introduction The causative organisms and clinical picture of com- munity-acquired pneumonia under normal social cir- cumstances are well defined. A few case reports and studies have suggested that pneumonia has a different picture and aetiology under what was called "extreme circumstances ''1 in "disaster regions ''2 and camps in de- veloping countries. 2' 3 The combination of overcrowding, exhaustion, and poverty has resulted in a high incidence of pneumonia generally, and in particular, outbreaks of Mycoplasma pneumonia< and a "caseous" form of pul- monary tuberculosis characterized by severe systemic effects and high mycobacterial load. 1 Pilgrimage to Mald¢ah in Arabia is a unique phe- nomenon with important medical and epidemiological implications which could serve as a model for a setting of "extreme circumstances". Millions of pilgrims, mostly elderly subjects from poor countries with a high pre- valence of infectious diseases like tuberculosis, 4 follow air * Address all correspondence to: A. Alzeer, Consultant Pulmonologist & Intensivist, Department of Medicine (38), College of Medicine, King Saud University, P.O. Box 18321, Riyadh 11415, Saudi Arabia. Accepted for publication 25 September 1997. travel by gathering under crowded conditions (mostly tents) to perform physically-exhausting religious rites. The pilgrimage usually lasts for a few weeks. Although heat stroke in association with adult respiratory distress syndrome and disseminated intravascular coagulopathy are the best described complications of pilgrimage, s a few reports and anecdotal evidence point to a high incidence of meningitis 6 and respiratory tract infection complicated by high mortality. We decided, therefore, to conduct a study to determine the aetiology, clinical features and outcome of severe pneumonia requiring hospital ad- mission among pilgrims to Makkah. Materials and Methods This cross-sectional study was carried out in two main referral hospitals in the Makkah area (A1-Noor Specialist Hospital and King Abdulaziz Hospital) during the whole of the pilgrimage season, extending between 3 and 28 May 1994. All pilgrims admitted to hospital with pneu- monia were included. Nearly all were referred from hajj camps. For the purpose of the study, pneumonia was defined as an acute episode associated with respiratory symptoms 0163-4453/98/030303 + 04 $12.00/0 © 1998 The British Infection Society