Wendy Page

Impact of an Ivermectin Mass Drug Administration on Scabies Prevalence in a Remote Australian Aboriginal Community

Background Scabies is endemic in many Aboriginal and Torres Strait Islander communities, with 69% of infants infected in the first year of life. We report the outcomes against scabies of two oral ivermectin mass drug administrations (MDAs) delivered 12 months apart in a remote Australian Aboriginal community. Methods Utilizing a before and after study design, we measured scabies prevalence through population census with sequential MDAs at baseline and month 12. Surveys at months 6 and 18 determined disease acquisition and treatment failures. Scabies infestations were diagnosed clinically with additional laboratory investigations for crusted scabies. Non-pregnant participants weighing ≥15 kg were administered a single 200 μg/kg ivermectin dose, repeated after 2–3 weeks if scabies was diagnosed, others followed a standard alternative algorithm. Principal Findings We saw >1000 participants at each population census. Scabies prevalence fell from 4% at baseline to 1% at month 6. Prevalence rose to 9% at month 12 amongst the baseline cohort in association with an identified exposure to a presumptive crusted scabies case with a higher prevalence of 14% amongst new entries to the cohort. At month 18, scabies prevalence fell to 2%. Scabies acquisitions six months after each MDA were 1% and 2% whilst treatment failures were 6% and 5% respectively. Conclusion Scabies prevalence reduced in the six months after each MDA with a low risk of acquisition (1–2%). However, in a setting where living conditions are conducive to high scabies transmissibility, exposure to presumptive crusted scabies and population mobility, a sustained reduction in prevalence was not achieved. Clinical Trial Registration Australian New Zealand Clinical Trial Register (ACTRN—12609000654257).

Strongyloides seroprevalence before and after an ivermectin mass drug administration in a remote Australian Aboriginal community

Background Strongyloides seroprevalence is hyper-endemic in many Australian Aboriginal and Torres Strait Islander communities, ranging from 35–60%. We report the impact on Strongyloides seroprevalence after two oral ivermectin mass drug administrations (MDAs) delivered 12 months apart in a remote Australian Aboriginal community. Methods Utilizing a before and after study design, we measured Strongyloides seroprevalence through population census with sequential MDAs at baseline and month 12. Surveys at months 6 and 18 determined changes in serostatus. Serodiagnosis was undertaken by ELISA that used sonicated Strongyloides ratti antigen to detect anti-Strongyloides IgG. Non-pregnant participants weighing ≥15 kg were administered a single 200 μg/kg ivermectin dose, repeated after 10–42 days if Strongyloides and/or scabies was diagnosed; others followed a standard alternative algorithm. A questionnaire on clinical symptoms was administered to identify adverse events from treatment and self-reported symptoms associated with serostatus. Findings We surveyed 1013 participants at the baseline population census and 1060 (n = 700 from baseline cohort and 360 new entrants) at month 12. Strongyloides seroprevalence fell from 21% (175/818) at baseline to 5% at month 6. For participants from the baseline cohort this reduction was sustained at month 12 (34/618, 6%), falling to 2% at month 18 after the second MDA. For new entrants to the cohort at month 12, seroprevalence reduced from 25% (75/297) to 7% at month 18. Strongyloides positive seroconversions for the baseline cohort six months after each MDA were 2.5% (4/157) at month 6 and 1% at month 18, whilst failure to serorevert remained unchanged at 18%. At 12 months, eosinophilia was identified in 59% of baseline seropositive participants and 89% of seropositive new entrants, compared with 47%baseline seronegative participants and 51% seronegative new entrants. Seropositivity was not correlated with haemoglobin or any self-reported clinical symptoms. Clinical symptoms ascertained on the day of treatment and 24–72 hrs after, did not identify any adverse events. Significance Two community ivermectin MDAs delivered 12 months apart by trained Aboriginal researchers in collaboration with non-Indigenous researchers resulted in a sustained and significant reduction in Strongyloides seroprevalence over 18 months. Similar reductions were seen in the baseline cohort and new entrants.

Strongyloidiasis: a case for notification in Australia?

TO THE EDITOR: Hillman and colleagues give an excellent overview of rapid response systems (RRSs).1 There is no doubt that this system of care that matches “the right people — with the right skills and knowledge — with the right patients at the right time” is a vast improvement on the usual traditional hierarchical referral model of care, particularly for patients in acute care hospitals whose condition is deteriorating.

The National Strongyloides Working Group in Australia 10 workshops on: commendations and recommendations

[Extract] Strongyloidiasis, caused by the intestinal helminth Strongyloides stercoralis, is commonly found in developing nations in tropical and subtropical regions. Strongyloidiasis was omitted by the World Health Organization (WHO) as one of the Soil Transmitted Helminths in their Neglected Tropical Diseases Roadmap and can therefore be considered one of the most neglected tropical diseases. Despite its reputation as a disease of developing countries, strongyloidiasis remains an important disease in Australia, particularly for Aboriginal and Torres Strait Islanders, and those living in remote communities.

The Unique Life Cycle of Strongyloides stercoralis and Implications for Public Health Action

Strongyloides stercoralis has one of the most complex life cycles of the human-infecting nematodes. A common misconception in medical and public health professions is that S. stercoralis in its biology is akin to other intestinal nematodes, such as the hookworms. Despite original evidence provided by medical and veterinary research about this unique helminth, many assumptions have entered the scientific literature. This helminth is set apart from others that commonly affect humans by (a) the internal autoinfective cycle with autoinfective larvae randomly migrating through tissue, parthenogenesis, and the potential for lifelong infection in the host, the profound pathology occurring in hyperinfection and systemic manifestations of strongyloidiasis, and (b) a limited external cycle with a single generation of free-living adults. This paper aims to review and discuss original research on the unique life cycle of S. stercoralis that distinguishes it from other helminths and highlight areas where increased understanding of the parasite’s biology might lead to improved public health prevention and control strategies.

Strongyloidiasis in Oceania

Strongyloidiasis is a potentially fatal disease caused by species of Strongyloides (Nematoda). In Oceania, two species infect humans: S. stercoralis and S. kellyi. S. stercoralis is widespread throughout Oceania and causes serious disease in any age group. S. kellyi is localised to Papua New Guinea and causes serious disease in infants. Infective larvae enter the body through the skin and migrate through the tissues. Adult females live in the mucosa of the proximal small intestine. The life cycle of S. stercoralis includes autoinfection, unusual in parasitic worms, whereby some of the offspring of the parasitic adults become infective in the lower intestine and complete the life cycle in the same person. This ensures that the infection persists, and the population of the worms can increase out of control, usually when the person is immunodeficient or immunosuppressed. The worms can be eliminated by oral ivermectin, and the person is probably cured if their serology is negative 6 months after treatment. This chapter contains details of the life cycles, transmission, clinical manifestations, diagnostic tests and how to interpret them, most effective treatment options, how to ensure that treatment has been effective and what to consider when developing effective prevention and control strategies.

Ivermectin mass drug administration program to treat endemic scabies and strongyloidiasis in a remote aboriginal community in northern Australia

Introduction: The climate of reform and change is evident in the current Australian health care system where significant challenges are faced due to a growing burden of chronic disease, an aging population, workforce issues, and unacceptable inequities in access to services and health outcomes. Improved management of chronic conditions and a focus on health promotion and prevention are key priority action areas. It is vital that the health workforce has the appropriate knowledge and skills to work in a holistic approach that allows them to contribute to the downstream, midstream, upstream actions that will be required to address the future challenges. This presentation describes workforce health promotion capacity building initiatives developed in Northern Australia. Methods and Materials: A range of courses have been developed to build workforce capacity including a 5-day Core Health Promotion Short Course and tertiary level courses including a postgraduate certificate, postgraduate diploma and Master of Public Health (Health Promotion). Results: Between 2007 and 2011, fourteen 5 day short courses in health promotion were conducted for 254 participants. Follow up impact evaluation shows that the courses succeed in providing knowledge, skills, confidence and enthusiasm to undertake health promotion work but that a lack of understanding of health promotion from co-workers and managers, lack of organisational support and commitment, lack of resources, competing clinical priorities, and lack of time were barriers for undertaking health postgraduate courses commenced in 2010. Conclusions: There is strong support for workforce development in health promotion in north Queensland. Short courses and tertiary level training are one way to achieve this. However shifting health service delivery to a more upstream approach to address chronic disease requires broader capacity building within health services and systems including leadership, partnerships, resource allocation and organisational development.

Argument for Inclusion of Strongyloidiasis in the Australian National Notifiable Disease List

Strongyloidiasis is an infection caused by the helminth, Strongyloides stercoralis. Up to 370 million people are infected with the parasite globally, and it has remained endemic in the Indigenous Australian population for many decades. Strongyloidiasis has been also reported in other Australian populations. Ignorance of this disease has caused unnecessary costs to the government health system, and been detrimental to the Australian people’s health. This manuscript addresses the 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). 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.