Improved diet will lower anaemia among NT Aborigines
High levels of anaemia and parasitic worms in Northern Territory Aboriginal communities could be reduced through improved diet and hygiene, according to a University of Queensland study.
Parasitology Department Associate Professor Paul Prociv and Dr Bart Currie, a senior infectious diseases physician at the Royal Darwin Hospital, have conducted the first known systematic study of anaemia and gut parasites in a Northern Territory Aboriginal community.
University Parasitology Department PhD student Kieran Aland undertook field work to collect and later analyse specimens for parasitic infections during different seasons.
Around 300 members of the Elcho Island community in Arnhem Land, about 500kms east of Darwin, were screened for anaemia and parasitic worms during the two-year study beginning in 1994.
The study was funded by a two-year, $112,000 grant from the National Health and Medical Research Council's Public Health Research and Development Committee. It found a third of the adolescents and adults and an even higher proportion of children were anaemic while 25 percent were infected with hookworm.
Dr Prociv said 88 percent of the community was also found to be infected with the whipworm, Trichuris trichiura, probably reflecting the relative resistance of this species to anti-worm medications used sporadically in the community for many years.
Other significant intestinal parasites detected were: Strongyloides stercoralis (10?20 percent prevalence), Hymenolepis nana (15 percent), Entamoeba species. (17 percent) and Giardia duodenalis (eight percent).
Dr Prociv said iron deficiency accounted for almost all cases of anaemia. In adults, it predominantly affected women as their iron reserves were depleted by menstruation and pregnancy.
The researchers found that the only hookworm species present in people was Ancylostoma duodenale. It was more difficult to eradicate than other species commonly found in humans, Necator americanus, because of its ability to resist certain medications and to lie dormant, as larvae, in human tissues, such as muscle, indefinitely.
Dr Prociv said it was previously thought the hookworm present in Northern Territory Aborigines was the less aggressive Necator americanus, as this species predominated in nearby Papua New Guinea and parts of South-East Asia and Oceania.
The study found that while hookworm infection could contribute to anaemia in the community, the major cause of anaemia was much more likely to be poor diet.
Dr Prociv said more effective education about the importance of hygiene and nutritious food was urgently needed in Northern Territory Aboriginal communities afflicted by anaemia and parasitic worms.
"While many Elcho Island Aborigines ate so-called Obush tucker' such as fish, crabs, crayfish and shellfish, this was done sporadically and the great bulk of their nutritional needs were derived from refined foods purchased in the trade store, including flour-based foods (bread and biscuits), rice, potato chips and sweets. Meat and vegetables were bought infrequently," Dr Prociv said.
He said studies in Asia and Africa showed that treatment of hookworm anaemia with a diet rich in proteins, such as fish, meat and eggs, improved the condition within weeks and also led to a reduced prevalence of worms. Merely treating the worm infection meant anaemia could take years to respond, he said.
"In other words, parasite suppression will be of only marginal benefit to community nutritional status. The major challenge will be to raise community awareness of these and related health issues. Community control and individual participation will be essential in such programs," he said.
Ancylostoma duodenale hookworms measure around one-centimetre long and live in the human small intestine where they suck blood and chew on the bowel lining. Each female hookworm can lay about 20,000 eggs a day in the bowel, and these eggs then pass out in faeces and contaminate the environment.
Hookworm larvae develop in damp soil and enter the body through bare feet or wet clothing after these make contact with contaminated ground or grass. Dr Prociv said it took the hookworm larvae only about 30 seconds from skin contact to penetrate the skin, usually through hair follicles, and infiltrate the body.
While invasive larvae could not be seen, the process often caused an itchy sensation and small bumps on the skin. To reach the intestine after penetrating the skin, larvae travel through the circulation, lungs and airways, from which they pass down the oesophagus.
Left untreated, heavy hookworm infections can kill humans, especially children, who in severe cases can present to health authorities with persistent bleeding from the bowel.
Improved hygiene was needed to reduce the prevalence of worms in Aboriginal communities, Dr Prociv said. "While sewered toilet facilities are provided, they are poorly maintained and are not used effectively by children even when they do work," he said.
For more information, contact Dr Prociv (telephone 3365 3306).
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