Locally acquired strongyloidiasis in remote Australia: why are there still cases?

Abstract

In Australia, strongyloidiasis primarily affects returned travellers, Vietnam veterans and refugees or asylum seekers, and First Nations people. Non-overseas acquired cases are seen almost exclusively in Australian First Nations remote communities. Australian First Nations communities have one of the highest rates of strongyloidiasis in the world. Our work has shown that strongyloidiasis is a disease of poverty. Acknowledging this is important—we need to shift the lens to socioeconomic factors, particularly environmental health hardware such as working toilets and sewerage systems, showers and laundries, and effective wastewater and rubbish removal. The rates of strongyloidiasis in First Nations communities is a result of decades of inadequate, poorly constructed and/or poorly maintained housing, and poor environmental health hardware (hereafter hardware). The solution lies in adequate funding, resulting in well designed and maintained housing and appropriate hardware. Governments need to allow First Nations communities themselves to take the lead role in funding allocation, and design, construction and maintenance of their housing and hardware. This will ensure housing and hardware fulfils cultural and physical needs and desires, and protects health. Improving housing and hardware will also improve other health outcomes.

This article is part of the Theo Murphy meeting issue ‘Strongyloides: omics to worm-free populations’.

1. Introduction

(a) . Strongyloidiasis

Strongyloidiasis is a parasitic helminth infection caused by the nematode Strongyloides stercoralis. The infection is transmitted through contact with contaminated soil or faeces, and its symptoms range from mild or asymptomatic [1] through to disseminated strongyloidiasis, which is almost invariably fatal [2].

It is most commonly found in tropical and subtropical regions, but also occurs in more temperate climates, including temperate areas in Australia [3–5]. Although considered a tropical disease (and as such is included on the World Health Organization's Neglected Tropical Diseases list) we have argued elsewhere that it is better described as a disease of disadvantage [6].

In Australia, strongyloidiasis primarily affects returned travellers, Vietnam veterans and refugees or asylum seekers [7,8], and First Nations people [9,10]. First Nations remote communities have some of the highest rates of strongyloidiasis in the world. In a recent study of seven remote communities in central Australia, Strongyloides spp. seroprevalence was 27% (5–42%) [5]. This is comparable with a study (based on literature and exploratory clinical audit) in central Australia that found 16% (30/186) of paediatric inpatients that were tested for S. stercoralis were seropositive [11]. Shield et al. [12] reported positive cases across all states and territories in Australia, with the highest (17–40% of those tested) in regions across where many First Nations people live in remote communities.

We know that person to person transmission is low or non-existent, based on a study of wives of Vietnam veterans in Australia who did not contract the disease [13]. Transmission of S. stercoralis occurs when a person comes into contact with human (and possibly dog) faeces. This contact occurs when the sewerage systems are inadequate (overflowing onsite wastewater treatment systems or toilets, or access to the waste stabilization ponds or other wastewater treatment systems), when someone comes into contact with human waste from open defaecation and when rubbish collection is inadequate (contact with nappies or other human waste). Reducing the risk of transmission also requires access to potable water for drinking, bathing and laundry. Notably, the Northern Territory Government body, NT Health (Northern Territory Health) Fact Sheet states ‘Good hygiene and sanitation is the best way to prevent Strongyloidiasis. The provision of functioning sewerage systems and avoiding faecal contamination of the soil are the most important preventative measures.’ [14] .

The high rates of strongyloidiasis in First Nations communities in Australia are a result of longstanding, systemic inequalities. For decades, these communities have faced the challenges of housing overcrowding, inadequate housing maintenance including of water and wastewater hardware, and inadequate waste management, all of which contribute to the transmission of strongyloidiasis.

(b) . Housing

Many First Nations communities have too few houses, resulting in extremely high levels of overcrowding [15,16]. Overcrowding increased during the COVID-19 pandemic, and in turn, this increased communities' vulnerability to the effects of COVID [17]. A quick search of recent news articles reveals the current extent of the problem, with reports of 20 people/house (Yarrabah, ABC News 23/1/22), 10–15 people/house (Rockhole, ABC News 19/3/22) and 8 people/house (Perth, ABC News 14/12/22). This is supported by many calls in the literature over the years to address overcrowding [18–20]. The 2021 Census indicated that 19% of First Nations people were living in overcrowded housing [21]. Overcrowding limits the ability of individuals to maintain personal and environmental hygiene conditions [10].

Overcrowding is caused by too few houses, and also because housing is not constructed to accommodate cultural and practical requirements. This includes the movement of people into and out of communities for cultural reasons such as funerals, and other activities such as sports. This means that houses can be required to house many more people than their design allows. This impacts on the functioning of environmental health hardware, particularly toilets, as sewage and sewerage systems do not cope with the increased demand beyond that for which they were designed. Designing and building housing that meets the needs and aspirations of those that live in remote communities is imperative.

(c) . Housing hardware

Adequate environmental health hardware includes functioning toilets, laundries and other bathroom facilities; provision of potable, tasteless and odourless drinking water; places to safely store and prepare food; and regular rubbish removal [22,23]. Environmental health hardware in First Nations communities has for decades been inadequate. Norris [24], 25 years ago, reported an ‘appalling state of Indigenous health and housing’. This remains unchanged, with Standen et al. [25] reporting that ‘health-related hardware in Aboriginal community housing across NSW pre-intervention has not significantly changed during the program's 20 years’. This is supported by a study in 2019 [26] indicating that the authors found ‘some evidence of a reduction in crowding but little observable improvement in the provision of maintenance and repairs'. Notably, Ali et al. [27] showed in their analysis of infectious diseases and housing maintenance that ‘the burden of infectious disease among Indigenous Australians can be reduced through improved housing conditions, adequate and timely housing repair and maintenance’.

A landmark study of First Nations communities' environmental health hardware found that its poor maintenance contributed significantly to the lack of functioning of these basic facilities [28]. Notably, the study found that only 10% of poor functioning was the result of vandalism or misuse, which is commonly held to be one of the main reasons for poor functioning of environmental health hardware. While this study was published some years ago, as noted above it is clear that this situation remains unchanged in many communities. Further, a study based on the same approach found that there was a 40% reduction in hospital separations of people from homes that had had their environmental health hardware repaired [25]. This shows clearly the link between functioning environmental health hardware and significantly better health outcomes. In addition, this study provides a concrete argument for the economics of well-funded, ongoing maintenance and repairs to these basic facilities.

Remote First Nations people are more likely to live in social housing than Indigenous Australians in non-remote areas (71% compared with 25%) [21]. This suggests that a significant proportion of the housing problems in remote communities—both the number of houses and housing maintenance—needs to be addressed by government landlords. These government landlords should be held to the same level of accountability as other landlords. For urgent repairs (such as a blocked toilet), most states require property managers to respond immediately and to attend to the problem within 24 h [29]. In the Northern Territory, the landlord has 5 business days after being notified to either make the repairs or advise arrangements for the repairs, which ‘must be finalized within 14 days of the tenant's notice being received’ [30]. For all other repairs, the ‘tenant must give notice and the landlord is obliged to repair’ [30]. If these repairs are not being undertaken—and it seems evident from the literature (and anecdotal evidence) that they are not—then this is in breach of the government landlord's legal responsibilities.

It is imperative that both State and Federal government and other organizations, including many of the Non Government Organizations (NGOs) that work in remote communities, work seriously to address these issues of housing and environmental health hardware problems in First Nations communities.

2. What can be done?

(a) . Allow first nations communities to take the lead

Decisions that affect First Nations people should be made by First Nations people themselves. Engagement and consultation with First Nations communities are imperative if any activity that affects them is being considered. However engagement should go beyond consultation. Communities must be able to take the lead in decision-making. This is especially important with respect to housing design, building and maintenance. Experience overseas emphasizes the importance of investing in Indigenous governance capacity and related resources [31]. In Australia, this can be achieved through investing in First Nations community-controlled organizations, giving the communities control over deciding how best to provide appropriate housing and environmental health hardware. This includes control of funding allocation, governance and training opportunities, as well as control of housing design, construction and maintenance. The success of Aboriginal Community Controlled Health Organizations (ACCHOs) [32–34] demonstrates the success of allowing communities to take ownership of decisions that affect them. Governments and NGOs must learn to trust First Nations communities to take the lead role in addressing housing and infrastructure.

Allocate sufficient funding to address housing and environmental health infrastructure

The ‘costs of remoteness’ are a challenge and it has been argued that these costs become higher when cultural design factors are considered [35]. However this is a cost that needs to be borne. Australia is a party to the International Covenant on Economic, Social and Cultural Rights, which states that ‘Every person has the right to an adequate standard of living, which includes the right to adequate housing (ICESCR, article 11)’ [36]. Additionally, the United Nations Sustainable Development Goals includes ‘Goal number 6: Ensure availability and sustainable management of water and sanitation for all’ (see https://sdgs.un.org/goals). All UN Member States adopted the SDGs in 2015, including Australia. ‘Closing the Gap’, an Australia Federal government initiative, has as one of its targets ‘Aboriginal and Torres Strait Island people secure appropriate, affordable housing that is aligned with their priorities and need’, with the specific target that ‘By 2031, increase the proportion of Aboriginal and Torres Strait Islander people living in appropriately sized (not overcrowded) housing to 88 percent’.

Australia is a very wealthy country. According to the World Bank, it ranks 13th in the world by GDP [37], and according to the Credit Suisse's 2022 Global Wealth Report Australia it has the highest median wealth per adult in the world [38]. This estimate is considered a more accurate measure of overall wealth. The fact that Australia has cases of locally acquired strongyloidiasis is an indictment of policies and investment in First Nations communities by successive State and Federal governments on both political sides. Appropriate investment should be made because it can be afforded.

Notably, investment in housing and environmental health hardware construction and maintenance will reduce the long-term costs associated with poor health. The economic cost associated with clinical care required to treat diseases is vast, with AUD$134 billion spent on specific diseases in 2018–2019 [39]. While the economic cost associated with strongyloidiasis has not been established, there are reports on the extremely high costs associated with other environmental health hardware-related illnesses prevalent in First Nations remote communities, such as Group A Streptococcus-related diseases, including rheumatic heart disease, for which Cannon et al. [40] estimate the annual economic healthcare cost to be AU$185.1 million.

In the study referred to above, hospital separations were significantly reduced by the maintenance of basic environmental health hardware [25]. Notably, hospital separations are a gross measure of overall health—this reduction in hospital admissions would be accompanied by a concomitant reduction in other illnesses not caught during hospital admissions. The global reduction in diarrheal diseases through improvements in environmental health hardware is well-described [41,42] and a significant meta-analysis published by Freeman et al. [43] concluded that ‘… evidence suggests that sanitation is protective against diarrhea, active trachoma, some STH infections [and] schistosomiasis' [43, p. 928].

Therefore there are both social justice and economic arguments for investing in both First Nations housing and environmental health infrastructure that should not be ignored.

(b) . Use environmental health-related disease—including strongyloidiasis—as a prompt for action

When a case of locally acquired strongyloidiasis (or other environmental health-related diseases such as group A streptococcal infections, including sequalae such as rheumatic heart fever and disease, other helminth infections, and scabies) is diagnosed, particularly in a child (as this indicates a recently acquired infection), immediate assessment of the housing and environmental health hardware in the patient's home and environment should be undertaken to find and address the causes of transmission. This would provide a prompt for action that is easily identified and therefore easily monitored. Environmental Health Officers and Environmental Health Workers are well versed in the environmental determinants of health and are ideally positioned to undertake this type of assessment [44,45].

Strongyloidiasis is an overlooked disease [46,47] that many clinicians are not familiar with [48]. This means that clinicians working with First Nations communities need to be made aware of the disease. This is a role for medical associations and universities, although significant effort has been made by the working group Strongyloides Australia (formerly the National Strongyloides Working Group), which is comprised of clinicians and researchers [49]. Ideally clinicians can then not only take responsibility for treatment of the individual, but also play a role in notifying the relevant parties that there are environmental health issues that need to be addressed.

The role of dogs in the transmission of strongyloidiasis is not clear [50,51]. Notwithstanding, in the absence of evidence to the contrary, dogs should be assumed to play a role in transmission. This requires well funded, ongoing support for veterinarian services in remote First Nations communities, which has the additional benefit of addressing other zoonoses. A One Health approach that focuses on healthy companion animals and a healthy environment is considered to be the gold standard for health [52,53].

(c) . Make strongyloidiasis notifiable

Strongyloides Australia mapped strongyloidiasis in Australia against the criteria established by the Communicable Disease Network Australia (CDNA) in 2018 [54], showing that the disease fulfilled 12 criteria required for a disease to be included in the Australian National Notifiable Disease List (NNDL) under the National Health Security Act 2007 (Commonwealth).

Notably, we found that

‘there are six main arguments that provide compelling justification for strongyloidiasis to be made nationally notifiable and added to the Australian NNDL. These are: The disease is important to Indigenous health, and closing the health inequity gap between Indigenous and non-Indigenous Australians is a priority; a public health response is required to detect cases of strongyloidiasis and to establish the true incidence and prevalence of the disease; there is no alternative national surveillance system to gather data on the disease; there are preventive measures with high efficacy and low side effects; data collection is feasible as cases are definable by microscopy, PCR, or serological diagnostics; and achievement of the Sustainable Development Goal (SDG) # 6 on clean water and sanitation’ [54].

Inclusion in the NNDL will allow a better understanding of the rates of strongyloidiasis, highlight strongyloidiasis to clinicians working in remote First Nations communities and importantly, prompt an investigation into the environmental health hardware failings that are resulting in strongyloidiasis transmission.

3. Conclusion

Strongyloidiasis is a disease that should not be present in Australian First Nations communities. The disease is transmitted by contact with faeces as a result of poor sewerage provision—including failing onsite wastewater systems—and contact with waste stabilization ponds or other treatment systems, or faeces resulting from al fresco defecation, or contact with rubbish, particularly nappies. Overcrowded housing diminishes the capacity for environmental health hardware to cope with the demand, and its poor maintenance results in lack of functionality of these systems. The functionality of environmental health hardware is imperative in maintaining good health. Providing adequate funding, together with giving First Nations communities control over housing design, construction and maintenance, and control over funding allocation, governance and training opportunities, are essential steps to addressing the housing and environmental health hardware problems that cause strongyloidiasis transmission. Additionally, making strongyloidiasis a notifiable disease, together with using cases as a prompt for action, will help to eliminate this disease.

Data accessibility

This article has no additional data.

Authors' contributions

K.R.: conceptualization, writing—original draft, writing—review and editing.

Conflict of interest declaration

I declare I have no competing interests.

Funding

I received no funding for this study.