other rod-shaped Gram negative bacteria. The disease associated 

 with Legionella is a severe pneumonia, with symptoms including 

 high fever, abscess formation, diarrhea, neurologic symptoms and 

 possible kidney and liver damage, (Weiss, 1981). In the 

 environment, Legionella are present in soil and in water. L. 

 bozemanii was isolated from a Navy diver who died of acute 

 bronchopneumonia, following a diving exercise ( Bozeman et al., 

 1968; Brenner et al., 1980). A similar isolate was recovered 

 from a fatal case of pneumonia in a patient who had been thrown 

 from a boat into murky swamp water, where he swam for 15-20 

 minutes before being rescued. The victim was on antileukemic and 

 immunosuppressive therapy ( Thomason et al., 1979). Thus, 

 Legionella spp. may pose a potential threat to divers and a 

 serious threat to the immunocompromised individual. 



Viable But Non-Culturable Bacteria 



It has been reported by Grimes et al . (1986) that 

 allochthonous enteric pathogens can survive for long periods of 

 time in seawater despite the high salt concentration, low 

 temperature and reduced nutrient concentration of seawater. 

 Under such conditions, bacteria can enter into a dormant phase 

 during which they remain viable and potentially virulent. The 

 direct viable count ( DVC ) , a technique developed by Kogure et 

 al. (1979) is useful in detecting allochthonous bacteria in the 

 marine environment that do not die when introduced into seawater. 

 Although the bacterial cells become non-culturable, they retain 

 virulence, as shown by positive response in rabbit ligated ileal 

 loops (Colwell et al., 1985). Similarly, an environmental 

 isolate of Salmonella enteritidis was shown by Roszak et al. 

 (1984) to become non-culturable within 48 hours after being 

 inoculated into a sterile Potomac River water microcosm. Xu et 

 al. (1982) documented the persistence of viable E. coli and V. 

 cholerae , even when the organisms were no longer detectable by 

 conventional culture methods. Rollins and Colwell (1986) 

 reported that Campylobacter jejuni also converts to a non- 

 culturable state under adverse conditions. The implication 

 regarding diving hazards is that while viable but non-culturable 

 cells cannot be detected by conventional techniques, they still 

 pose a potential hazard to divers, evidenced by their return to a 

 virulent state upon passage through an animal system. 



PRECAUTIONS 



It is clear that military and commercial divers who must 

 enter polluted waters may be exposed to a wide variety of 

 pathogens including protozoans and both culturable and non- 

 culturable bacteria. Preventative measures should be taken to 

 reduce the risk of contracting waterborne infections. 



A commonly used measure against ear infection is acetic 

 acid application. Brook et al. (1982) carried out a study in 



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