STAPHYLOCOCCI IN NOSES AND STREPTOCOCCI IN THROATS OF ISOLATED AND SEMI-ISOLATED ANTARCTIC COMMUNITIES

A microbial culture system for use in remote field environments

Field studies of human flora carried out in remote environments are often compromised by problems associated with media, equipment or cargo limitations. For the International Biomedical Expedition to Antarctica an anaerobic culture system was developed based on sealed vials, pre-reduced anaerobically sterilized media, antibiotic selective media and compact processing equipment. The system proved simple to use in a harsh environment and gave results comparable with standard plate and roll-tube techniques. No problems with dehydration, contamination or oxidation were encountered. Furthermore, the system preserved viability of primary isolates for up to 6 months of storage.

Staphylococcal epidemiology in Antarctica

An investigation of staphylococcal epidemiology was undertaken at an Australian National Antarctic Research Expedition station during 1965-1966. It concerned the carriage of staphylococci by the men and their dogs, and the occurrence of staphylococci in the station environment. The year-long study indicated that coagulase-negative strains survived better in the Antarctic environment than coagulase-positive strains. It was demonstrated that naturally acquired coagulase-positive strains could not maintain colonization on forearm skin under the usual cold exposure experienced at Mawson station, though coagulase-negative skin strains appeared to thrive during the winter. Staphylococcus albus and S. aureus were able to persist in the anterior nares, despite the sometimes lower temperatures recorded in this micro-climate, probably because of the greater humidity and denser populations found there. The majority of the nasal carriers of S. aureus were persistent carriers, only two men in 27 being found to be occasional carriers of nasal strains, which was consistent with the observation that transfer of this pathogen from man to man is not common under Antarctic conditions. Half of the 27 sledge dogs at the station were found to carry coagulase-positive staphylococci but this did not appear to be of pathological significance to their human handlers. The local inanimate environment, including mess hut, sleeping huts and sleeping bags used on expeditions, was searched for contamination by S. aureus but none was detected.

The epidemiology of respiratory infection in an isolated Antarctic community

The results of a combined clinical and laboratory study of respiratory infections among members of an Australian Antarctic expedition are presented. Virus isolation and serological methods were employed, but the aetiological agent or agents responsible for respiratory infections in this group were not revealed.

The clinical findings were correlated with published and unpublished studies on comparable communities, and the following broad pattern of the epidemiology of respiratory tract infections in such groups has emerged. The assembly on board ship of a party from widely separated areas often leads to infections after embarkation. On long voyages these infections may burn out, but frequently new cases are still appearing when the party arrives in Antarctica. Symptoms in sufferers at this time become more severe, suggesting that the sudden environmental change from the warmth of an air-conditioned ship to the harsher Antarctic conditions may influence the course of the respiratory infections. With isolation established in Antarctica, further cases rarely appear. On exposure to the relief party, however, infections can be expected, and it is noted that morbidity is usually low and symptoms are mild, indicating an apparent heightened resistance to infection in the acclimatized party while still on the ice.

This study has further shown that most of these men, on returning to urban societies, contracted moderately severe upper respiratory tract infections in contrast to their apparent resistance when under Antarctic conditions.

The suitability of these groups for experimental study, including the inoculation of volunteers, was discussed and suggestions were made for future work.