Trends in Strongyloides stercoralis Faecal Larvae Detections in the Northern Territory, Australia: 2002 to 2012

Abstract

Strongyloides stercoralis is a soil-transmitted helminth (STH) endemic to tropical and subtropical areas. We reviewed the temporal detection trends in patients with S. stercoralis larvae present in faecal samples, in Northern Territory (NT) Government Health facilities, between 2002 and 2012. This was a retrospective observational study of consecutive patients with microbiologically confirmed detection of S. stercoralis in faeces. The presence of anaemia, eosinophilia, polyparasitism, and geographic and demographic data, were included in the assessment. S. stercoralis larvae were present in 389 of 22,892 faecal samples (1.7%) collected across the NT over 11 years, examined by microscopy after formol ethyl acetate concentration. 97.7% of detections were in Indigenous patients. Detections, by number, occurred in a biphasic age distribution. Detections per number of faecal samples collected, were highest in the 0–5 year age group. Anaemia was present in 44.8%, and eosinophilia in 49.9% of patients. Eosinophilia was present in 65.5% of the ≤5 age group, compared to 40.8% of >5 year age (p < 0.0001). Polyparasitism was present in 31.4% of patients. There was an overall downward trend in larvae detections from 2.64% to 0.99% detections/number of faecal samples year between 2002 and 2012, consistent with the trends observed for other local STHs. S. stercoralis remains an important NT-wide pathogen.

Paediatric Strongyloidiasis in Central Australia

“…Children are over-represented in population estimates of strongyloidiasis. A Territory-wide study examining faecal larval detection between 2002 and 2012 found that children under five represented 42.2% of diagnoses, with rates of 3–6% of stool samples examined compared to 1.7% of samples overall [ 9 ]. A study of patients diagnosed with strongyloidiasis by faecal microscopy at Royal Darwin Hospital also identified that patients under five years of age were disproportionately represented, with 54% of cases falling in this age group [ 13 ].…”

“…The Strongyloides genus includes over fifty species capable of establishing parasitic infections in a range of animal hosts, and two species are known to infect humans [ 8 ]. Strongyloides fuelleborni is present in Papua New Guinea and Africa, while S. stercoralis is endemic throughout southern Europe, Africa, Asia, the Americas, and the northern two-thirds of Australia [ 2 , 9 ].…”

“…Some remote Australian Indigenous communities have S. stercoralis seroprevalences approaching 60%, putting them amongst the highest in the world [ 2 , 10 , 11 ]. Within these communities, Indigenous children have a higher documented prevalence of strongyloidiasis than any other age group [ 9 , 12 , 13 , 14 , 15 , 16 ].…”

Neglected and Emerging Tropical Diseases in South and Southeast Asia and Northern Australia

“…They each contribute to a much better understanding of Neglected and Emerging Tropical Diseases in South and Southeast Asia and Northern Australia. The contributions to these topics can be summarized as follows: four submissions on LFs [ 2 , 3 , 4 , 5 ], four submissions on STHs [ 6 , 7 , 8 , 9 ], two submissions on rickettsial diseases [ 10 , 11 ], and one submission on arboviral diseases [ 12 ]. A systematic review and meta-analysis leads the opening section on LF [ 2 ], which reviews prevalence and disease burden of LF in southeast Asia [ 2 ].…”

“…A review paper leads the other major section on STH, which focuses on the prevalence of STHs in different groups, including immigrants, travellers, military personnel and veterans in Australia and Asia [ 6 ]. This is followed by studies examining an extended period of surveillance data on Strongyloides stercoralis [ 7 ]; and a study examining the prevalence of STHs in remote Aboriginal communities, both in the Northern Territory, Australia [ 8 ]; and a study examining the links between dietary intake, nutritional status, and intestinal parasites, such as Schistosoma japonicum , Ascaris lumbricoides , Trichuris trichiura , and hookworm, in the Philippines [ 9 ]. The two rickettsial papers examine hospital admissions for Queensland tick typhus in north Brisbane, Australia [ 10 ], and the other study based in Thailand looks at the influence of land use on scrub typhus in rodents [ 11 ].…”