Vibrio species (Seidler et al., 1980b). Isolates also included 

 two genera of obligate anaerobes, Bacteroides and Clostridium , 

 several of which were shown to be cytotoxic for Y-l adrenal 

 cells. Fecal coliform counts from these waters numbered from 

 lxlO 2 to 5x10^/100 ml, indicating significant levels of 

 pollution. These investigators also examined the ears, noses, 

 throats and equipment of divers after the divers had been exposed 

 for 30 minutes to Anacostia River water. This survey was 

 conducted in August and October when the water temperature was 

 20°C and 13°C respectively. 



In August, when the water temperature was higher, 90% of the 

 divers' ears and masks were found to become colonized. With a 

 drop in water temperature, the colonization rates were lower, 

 except for the divers' ears which again were colonized in 90% of 

 the divers. The differences probably reflect changes in the 

 microbial populations during the different seasons. Also 

 reported was the observation that exposure to polluted water for 

 only 30 minutes resulted in significant change in the skin flora 

 of the divers, such that it reflected the flora of the diving 

 environment. This has obvious implications for divers who are 

 required to enter heavily polluted waters. 



Protozoans 



Some exposure to potentially pathogenic protozoans in 

 polluted water is likely (Daggett, 1981). There are two genera 

 of amphizoic amoebae of primary concern to divers: Naegleria and 

 Acanthamoeba . There is not a large number of human cases 

 involving Naegleria or Acanthamoeba , but most cases have been 

 associated with water, in particular, thermally polluted 

 freshwater. The only known pathogenic Naegleria species is N. 

 fowleri , which causes primary amoebic encephalitis. This amoeba 

 infects humans by entry through the nose, and, therefore, poses a 

 risk to divers, if the polluted water leaks through the facemask 

 during a dive. 



Reported cases of Acanthamoeba include eye infections, 

 respiratory infections, and granulomatous amoebic encephalitis 

 (Daggett, 1981; Martinez et al . , 1980; Powers et al., 1978). 

 Entry into the body may be via inhalation, nasal route, inges- 

 tion, or through a wound. Acanthamoeba isolated by Sawyer et al . 

 (1977) from sediment collected from the Baltimore Harbor were 

 found to be pathogenic when tested in the laboratory. Sawyer 

 (1980) has also found that Acanthamoeba can be isolated from 

 clean sediment as well as active ocean dump sites. It has been 

 reported that sites from which Acanthamoeba are readily isolated 

 often are sites of elevated coliform counts (Daggett, 1981). 



In addition to the amphizoic amoebae, two obligately 

 parasitic protozoans, which may be a hazard for divers, are 

 Entamoeba histolytica and Giardia lamblia . Both organisms cause 



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