Could tourist boots act as vectors for disease transmission in Antarctica?

Effectiveness Evaluation of a UV-C-Photoinactivator against Selected ESKAPE-E Pathogens

Healthcare-associated infections (HAI) worldwide includes infections by ESKAPE-E pathogens. Environmental surfaces and fomites are important components in HAI transmission dynamics, and shoe soles are vectors of HAI. Ultraviolet (UV) disinfection is an effective method to inactivate pathogenic microorganisms. In this study, we investigated whether the SANITECH UV-C shoe sole decontaminator equipment that provides germicidal UV-C radiation could effectively reduce this risk of different pathogens. Six standard strains and four clinical MDR strains in liquid and solid medium were exposed to a UV-C System at specific concentrations at other times. Bacterial inactivation (growth and cultivability) was investigated using colony counts and resazurin as metabolic indicators. SEM was performed to assess the membrane damage. Statistically significant reduction in cell viability for all ATCCs strains occurred after 10 s of exposure to the UV-C system, except for S. enterica, which only occurred at 20 s. The cell viability of P. aeruginosa (90.9%), E. faecalis and A. baumannii (85.3%), S. enterica (82.9%), E. coli (79.2%) and S. aureus (71.9%) was reduced considerably at 20 s. In colony count, after 12 s of UV-C exposure, all ATCC strains showed a 100% reduction in CFU counts, except for A. baumannii, which reduced by 97.7%. A substantial reduction of colonies above 3 log₁₀ was observed at 12 and 20 s in all bacterial strains tested, except for A. baumannii ATCC 19606 (12 s). The exposure of ATCCs bacterial strains to the UV-C system for only 2 s was able to reduce 100% in the colony forming units (CFU) count in all ATCCs strains, S. aureus, P. aeruginosa, E. coli, A. baumannii, E. faecalis, except the S. enterica strain which had a statistically significant reduction of 99.7%. In ATCC strains, there was a substantial decrease in colonies after 4 s (sec) of exposure to the UV-C system, with a reduction ranging from 3.78-4.15 log₁₀ CFU/mL. This reduction was observed in MDR/ESKAPE-E strains within 10 s, showing that UV-C could eliminate above 3.84 log₁₀ CFU/mL. SEM showed a reduction of pili-like appendages after UV-C treatment in all strains except for E. coli (ATCC 25922). The Sanitech UV-C shoe sole decontaminator equipment from Astech Serv. and Fabrication Ltd. (Petrópolis, Brazil), effectively killed in vitro a series of ATCCs and MDR/ESKAPE-E bacteria of sanitary interest, commonly found in the hospital environment.

What are the real environmental impacts of Antarctic tourism? Unveiling their importance through a comprehensive meta-analysis

Human activities in Antarctica were increasing before the COVID-19 pandemic, and tourism was not an exception. The growth and diversification of Antarctic tourism over the last few decades have been extensively studied. However, environmental impacts associated with this activity have received less attention despite an increasing body of scholarship examining environmental issues related to Antarctic tourism. Aside from raising important research questions, the potential negative effects of tourist visits in Antarctica are also an issue discussed by Antarctic Treaty Consultative Parties. This study presents the results of a meta-analysis of scholarly publications that synthesizes and updates our current knowledge of environmental impacts resulting from Antarctic tourism. A first publication database containing 233 records that focussed on this topic was compiled and subjected to a general bibliometric and content analysis. Further, an in-depth content analysis was performed on a subset of 75 records, which were focussed on showing specific research on Antarctic tourism impacts. The main topic, methods, management proposals, and research gaps highlighted by the respective authors of these 75 publications were assessed. The range of research topics addressed, the methods used - including the application of established research designs from the field of environmental impact assessment -, and the conclusions reached by the study authors are discussed. Interestingly, almost one third of the studies did not detect a direct relationship between tourism and significant negative effects on the environment. Cumulative impacts of tourism have received little attention, and long-term and comprehensive monitoring programs have been discussed only rarely, leading us to assume that such long-term programs are scarce. More importantly, connections between research and policy or management do not always exist. This analysis highlights the need for a comprehensive strategy to investigate and monitor the environmental impacts of tourism in Antarctica. A first specific research and monitoring programme to stimulate a debate among members of the Antarctic scientific and policy communities is proposed, with the ultimate goal of advancing the regulation and management of Antarctic tourism collaboratively.

Understanding how best to engage recreationists in biosecurity to reduce the impacts of tree diseases: a review

Pests and diseases introduced from other countries are known to pose a threat to trees, woods and forests in many locations throughout the world. Once introduced they can be spread inadvertently by countryside visitors hiking, biking or riding along paths and trails through wooded areas. Engaging and communicating with these groups of countryside users to encourage and facilitate positive biosecurity behaviours is crucial for the future resilience of trees, woods and forests. This review draws on literature outlining principles for stakeholder engagement in forestry as well as evaluations of biosecurity campaigns from around the world. Key points are briefly presented for communicators aiming to encourage better biosecurity in the countryside. These include, the need to design campaigns based on the values and motivations of recreationists, using trusted information sources and understanding the importance of combining information with facilities so as to reduce the cost (in terms of effort and inconvenience) to hikers and other countryside users.

Adaptive Management of Sustainable Tourism in Antarctica: A Rhetoric or Working Progress?

Growth and diversification of tourism activities in Antarctica have not been matched by proactive strategies for planning or management. Recognizing that the adaptive management approach has been effectively implemented in managing tourism in protected areas, we examine to what extent this approach has been incorporated into the Antarctic tourism research and management, and what constraints exist for its implementation. To better understand the extent of literature contributions, we conducted an appraisal of 72 peer-reviewed journal articles published from 1992 to 2020 and Antarctic management documents. From a scientific perspective, researchers have been advocating for adaptive management approaches to Antarctic tourism and have applied different elements, particularly ecological assessments, design of management measures, monitoring, and regulatory mechanisms. However, these contributions have not been necessarily translated into management policy and regulations. We acknowledge that full implementation of an adaptive management approach is not easily achievable due to the unique Antarctic regime. However, we argue that comprehensive site-specific and regional adaptive management models could be applied as the first step for a more systematic implementation. This incremental approach could contribute to enhanced stakeholder participation and improved decision-making processes, ultimately leading to a more proactive and effective management of Antarctic tourism, essential for the conservation of the continent.

Do humans spread zoonotic enteric bacteria in Antarctica?

Reports of enteric bacteria in Antarctic wildlife have suggested its spread from people to seabirds and seals, but evidence is scarce and fragmentary. We investigated the occurrence of zoonotic enteric bacteria in seabirds across the Antarctic and subantarctic region; for comparison purposes, in addition to seabirds, poultry in a subantarctic island was also sampled. Three findings suggest reverse zoonosis from humans to seabirds: the detection of a zoonotic Salmonella serovar (ser. Enteritidis) and Campylobacter species (e.g. C. jejuni), typical of human infections; the resistance of C. lari isolates to ciprofloxacin and enrofloxacin, antibiotics commonly used in human and veterinary medicine; and most importantly, the presence of C. jejuni genotypes mostly found in humans and domestic animals but rarely or never found in wild birds so far. We also show further spread of zoonotic agents among Antarctic wildlife is facilitated by substantial connectivity among populations of opportunistic seabirds, notably skuas (Stercorarius). Our results highlight the need for even stricter biosecurity measures to limit human impacts in Antarctica.

Human-mediated dispersal of terrestrial species between Antarctic biogeographic regions: A preliminary risk assessment

The distribution of terrestrial biodiversity within Antarctica is complex, with 16 distinct biogeographic regions (Antarctic Conservation Biogeographic Regions) currently recognised within the Antarctic continent, Peninsula and Scotia Arc archipelagos of the Antarctic Treaty area. Much of this diversity is endemic not only to Antarctica as a whole, but to specific regions within it. Further complexity is added by inclusion of the biodiversity found on the islands located in the Southern Ocean north of the Treaty area. Within Antarctica, scientific, logistic and tourism activities may inadvertently move organisms over potentially long distances, far beyond natural dispersal ranges. Such translocation can disrupt natural species distribution patterns and biogeography through: (1) movement of spatially restricted indigenous species to other areas of Antarctica; (2) movement of distinct populations of more generally distributed species from one area of Antarctica to another, leading to genetic homogenisation and loss of assumed local patterns of adaptation; and (3) further dispersal of introduced non-native species from one area of Antarctica to another. Species can be moved between regions in association with people and cargo, by ship, aircraft and overland travel. Movement of cargo and personnel by ship between stations located in different biogeographic regions is likely to present one of the greatest risks, particularly as coastal stations may experience similar climatic conditions, making establishment more likely. Recognising that reducing the risk of inter-regional transfer of species is a priority issue for the Antarctic Treaty Consultative Meeting, we make practical recommendations aimed at reducing this risk, including the implementation of appropriate biosecurity procedures.

An analysis of environmental incidents for a national Antarctic program

Research stations in Antarctica are concentrated on scarce ice-free habitats. Operating these stations in the harsh Antarctic climate provides many challenges, including the need to handle bulk fuel and cargo increasing the risk of environmental incidents. We examined 195 reports of environmental incidents from the Australian Antarctic Program, spanning six years, to investigate the impacts and pathways of contemporary environmental incidents. Fuel and chemical spills were most common, followed by biosecurity incursions. The majority of reports were assessed as having insignificant actual impacts. Either the incidents were small, or active, rapid response and mitigation procedures minimised impact. During the period only one spill report (4000 l) was assessed as a 'high' impact. This is despite over 13 million litres of diesel utilised. The majority of incidents occurred within the existing station footprints. The pathways leading to the incidents varied, with technical causes predominately leading to spills, and procedural failures leading to biosecurity incursions. The large number of reports with inconsequential impacts suggest an effective environmental management system with a good culture of reporting environmental incidents. Our findings suggest that the key to continual improvement in an ongoing environmental management system is to learn from incidences and take action to prevent them occurring again, with an end-goal of minimising the residual risk as much as possible.

Prevention of microbial species introductions to the Arctic: The efficacy of footwear disinfection measures on cruise ships

Biosecurity measures are commonly used to prevent the introduction of non-native species to natural environments globally, yet the efficacy of practices is rarely tested under operational conditions. A voluntary biosecurity measure was trialled in the Norwegian high Arctic following concern that non-native species might be transferred to the region on the footwear of travellers. Passengers aboard an expedition cruise ship disinfected their footwear with the broad spectrum disinfectant Virkon S prior to and in-between landing at sites around the remote Svalbard archipelago. The authors evaluated the efficacy of simply stepping through a disinfectant foot bath, which is the most common practice of footwear disinfection aboard expedition cruise ships in the Arctic. This was compared to a more time consuming and little-used method involving drying disinfected footwear, as proposed by other studies. The two practices were evaluated by measuring microbial growth on paired footwear samples before and after disinfection under both conditions. Step-through disinfection did not substantially reduce microbial growth on the footwear. Allowing disinfected footwear to dry, however, reduced the microbial burden significantly to lower levels. Thus, the currently adopted procedures used aboard ships are ineffective at removing microbial burden and are only effective when footwear is given more time to dry than currently granted under operational conditions. These findings underscore results from empirical research performed elsewhere and suggest the need to better relay this information to practitioners. It is suggested that footwear should minimally be wiped dry after step-through disinfection as a reasonable compromise between biosecurity and practicability.

Mechanisms for floor surfaces or environmental ground contamination to cause human infection: a systematic review

Shoe soles have been shown to transfer infectious microorganisms to floor and ground surfaces. However, the possible modes of transmission of infectious agents from floors or ground surfaces to human contact for infection have not been systematically reviewed. A systematic review was performed on articles indexed in medical databases (Medline, EMBASE, PubMed) using a pre-defined search strategy and MeSH terms (date of last search: 15 March 2016). Only primary research studies in English that investigated the transmission dynamics of infectious microorganisms from floor or ground surfaces to human infection were included. Extraction of articles was performed two independent reviewers using pre-defined data fields in an Excel sheet. Disagreements were resolved by consensus. Thirty studies met the inclusion criteria. Almost all hospital-associated microorganisms including methicillin-resistant Staphylococcus aureus, Clostridium difficile, and multidrug-resistant Gram-negative species were identified on floor or ground surfaces. Several modes of transmission dynamics, most commonly direct contact or aerosolization, were identified. In conclusion, interventions such as efficient cleaning of floor surfaces and vectors that transfer infectious organisms to floors such as shoe soles could be an effective infection control strategy to prevent human disease.

Shoe soles as a potential vector for pathogen transmission: a systematic review

Shoe soles are possible vectors for infectious diseases. Although studies have been performed to assess the prevalence of infectious pathogens on shoe soles and decontamination techniques, no systematic review has ever occurred. The aim of this study was to perform a systematic review of the literature to determine the prevalence of infectious agents on shoe bottoms and possible decontamination strategies. Three electronic bibliographic databases were searched using a predefined search strategy evaluating prevalence of infectious pathogens on shoe bottoms and decontamination strategies. Quality assessment was performed independently by two reviews with disagreements resolved by consensus. Thirteen studies were identified that supported the hypothesis that shoe soles are a vector for infectious pathogens. Methicillin-resistant Staphylococcus aureus, Clostridium difficile and multidrug-resistant Gram-negative species among other pathogens were documented on shoe bottoms in the health care setting, in the community and among food workers. Fifteen studies were identified that investigated decontamination strategies for shoe soles. A number of decontamination strategies have been studied of which none have been shown to be consistently successful at disinfecting shoe soles. In conclusion, a high prevalence of microbiological pathogens was identified from shoe soles studied in the health care, community and animal worker setting. An effective decontamination strategy for shoe soles was not identified. Studies are needed to assess the potential for contaminated shoes to contribute to the transmission of infectious pathogens.

Health of Antarctic birds: a review of their parasites, pathogens and diseases

Antarctic birds are not beyond the effects of parasites or pathogens. However, potential ecological consequences of wide-spread infections for bird populations in Antarctica have received little attention. In this paper, we review the information published about disease and parasites, and their effects on Antarctic birds. The information on host species, parasites and pathogens, and geographic regions is incomplete and data on ecological effects on the populations, including how birds respond to pathogens and parasites, are almost inexistent. We conclude that more research is needed to establish general patterns of spatial and temporal variation in pathogens and parasites, and to determine how such patterns could influence hosts. This information is crucial to limit the spread of outbreaks and may aid in the decision-making process should they occur.

Salmonella infections in Antarctic fauna and island populations of wildlife exposed to human activities in coastal areas of Australia

Salmonella infections in Antarctic wildlife were first reported in 1970 and in a search for evidence linking isolations with exposure to human activities, a comparison was made of serovars reported from marine fauna in the Antarctic region from 1982-2004 with those from marine mammals in the Northern hemisphere. This revealed that 10 (83%) Salmonella enterica serovars isolated from Antarctic penguins and seals were classifiable in high-frequency (HF) quotients for serovars prevalent in humans and domesticated animals. In Australia, 16 (90%) HF serovars were isolated from marine birds and mammals compared with 12 (86%) HF serovars reported from marine mammals in the Northern hemisphere. In Western Australia, HF serovars from marine species were also recorded in humans, livestock, mussels, effluents and island populations of wildlife in urban coastal areas. Low-frequency S. enterica serovars were rarely detected in humans and not detected in seagulls or marine species. The isolation of S. Enteritidis phage type 4 (PT4), PT8 and PT23 strains from Adélie penguins and a diversity of HF serovars reported from marine fauna in the Antarctic region and coastal areas of Australia, signal the possibility of transient serovars and endemic Salmonella strains recycling back to humans from southern latitudes in marine foodstuffs and feed ingredients.

Evaluation of current and novel protocols for disinfection of airplane passenger footwear under simulated conditions

Aerobic bacterial culture was used to compare the effectiveness of the current USDA footwear disinfection protocol for airplane passengers contacting livestock to a novel protocol. The current protocol consists of brushing and dipping shoe soles in 1% Virkon S. The number of bacteria was not different between shoes treated with the current protocol and untreated shoes. No shoes met the standard for disinfection after the current disinfection protocol was completed. The novel protocol consisted of brushing shoe soles, wiping soles with a cotton towel soaked in 1% Virkon S, and drying soles with paper towels. The number of bacteria was less (P<0.0001) on treated shoes compared to control shoes. Eighteen of 20 shoes (90%) cleaned using the novel protocol met the standard for disinfection. Direct comparison of the current and novel protocols found that the number of bacteria cultured was less (P<0.0001) after implementing the novel protocol compared to implementing the current protocol. Again, no shoes treated using the current protocol met the standard for disinfection after the current protocol was completed. Sixteen and 17 of 20 shoes (80--85%), respectively, met the standard for disinfection after the novel protocol was completed. Under conditions of this study, current US airport footwear disinfection protocols were inadequate to disinfect footwear when using aerobic bacteria as a marker for disinfection. We recommend implementation of the novel footwear disinfectant protocol for select passengers from international flights.