Gastroenteritis caused by enterotoxigenic E. coli and shigella resistant to a number of drugs was a major problem that frequently interfered with the duties of U.S. troops during Operation Desert Shield.

Fifteen Aeromonas isolates from various human infections and nine isolates from polluted water were identified as either Aeromonas hydrophila or Aeromonas sobria and examined for cytotoxigenicity, enterotoxigenicity, adherence to epithelial cells, and other virulence-associated factors, including proteases, lipases, elastases, and hemolysins. Two groups cf organisms (I and II) were distinguishable based on differences in median lethal doses in mice and cytotoxicity for Y-1 adrenal cells. Group I clinical and environmental strains had median lethal doses of <107 colony-forming units, were cytotoxic, frequently possessed several virulence-associated factors, and had lysine decarboxylase-positive or Voges-Proskauer-positive phenotypes or both. Piliation of Aeromonas was associated strongly with ability to adhere to human buccal cells, and these characteristics were associated with group I strains. Group Il clinical and environmental strains had median lethal doses of '107 colony-forming units, were not cytotoxic, and usually were lysine decarboxylase negative or Voges-Proskauer negative or both. Clinical strains in group II exhibited enterotoxigenicity, which was not detected in group Il environmental strains. A. sobria was more frequently associated with human infections; 13 of the 15 clinical strains were A. sobria, and 2 were A. hydrophila. On the other hand, the majority of the environmental strains (seven of nine) were A. hydrophila.Aeromonas species are ubiquitous, waterborne microorganisms that have been implicated repeatedly as the causative agents of clinical illnesses, often serious, ranging from gastrointestinal and wound infections to septicemia (4,8,9,12,18,25,26). In compromised patients these illnesses may be fatal. Whereas a small proportion of humans, approximately 1%, are carriers of Aeromonas (26), infections frequently are acquired as a direct result of exposure to water harboring this microorganism (8,9,12,27).

Aeromonas species were recovered from over 27% of 183 chlorinated drinking water samples collected during an 18-month period. Sixteen of 20 isolates tested elicited a cytotoxic response by Y-1 mouse adrenal cells. None of the strains was either enterotoxigenic by the rabbit ligated ileal loop assay, exhibited piliation, or showed significant mannose resistant adherence to human buccal cells. TheAeromonas isolates were further identified to beA. sobria and were resistant to ampicillin and susceptible to chloramphenicol, kanamycin, streptomycin, and tetracycline. Total coliform levels did not correlate withAeromonas densities in distribution water. With 85% of the samplings,Aeromonas occurred in distribution water when no coliforms were detectable by either the membrane filter or most-probable-number techniques. A significant correlation (P<.001) existed between standard plate count levels andAeromonas.

OBJECTIVES. The purpose of this study was to determine whether respiratory disease due to crowded living conditions and high levels of suspended and blowing sand had a major adverse impact on US military personnel during Operation Desert Shield. METHODS. A questionnaire survey was administered to 2598 combat troops stationed in Northeast Saudi Arabia for a mean of 102 days. Samples of surface sand from seven different locations were analyzed by scanning electron microscopy and x-ray diffraction. RESULTS. Among surveyed troops, 34.4% reported a sore throat, 43.1% complained of a cough, 15.4% complained of chronic rhinorrhea, and 1.8% were unable to perform their routine duties because of upper respiratory symptoms. Evaluation of sleeping accommodations indicated that complaints of a sore throat and cough were most closely associated with sleeping in air-conditioned buildings; in contrast, complaints of rhinorrhea were associated with exposure to the outdoor environment while living in tents. Sand samples consisted mostly of quartz, with just 0.21% by weight of respirable size (< 10 microns in diameter). CONCLUSIONS. These findings indicate that upper respiratory complaints were frequent among Operation Desert Shield troops and were related both to the troops' housing and to their exposure to the outside environment.

The incidence and etiology of travelers' diarrhea was studied in a crew of 1,914 sailors and marines aboard a U.S. Navy ship during a western Pacific deployment. Questionnaires completed by 301 troops indicated that 52% had at least one episode of diarrhea during the deployment; however, only 5% of the ship's company sought treatment. Enterotoxigenic Escherichia coli was the most commonly identified pathogen (23%), followed by Giardia lamblia (6%), Salmonella (3%), rotavirus (2%), and Shigella, Campylobacter jejuni, and Entamoeba histolytica (1% each). In 66% of the episodes no etiologic agent was found. None of the risk factors thought to be associated with travelers' diarrhea could be statistically associated with the diarrhea group in comparison to questionnaire respondents who denied having had the illness.