[KAMPALA] Treating infectious diseases in developing countries might lead to an increase in allergies, according to scientists in Uganda, raising moral issues about the treatment.
A study in Uganda has found that when pregnant women were treated for Schistosoma mansoni worm infections, which can cause anaemia, their children were more likely to develop skin allergies. The findings, based on more than 2,500 women, were published in the Journal Pediatric Allergy and Immunology last month (23 January).
"It is thought that the decrease in infectious illnesses is somehow associated with the increase in allergy," said the study's lead author, Harriet Mpairwe, a senior medical officer with the Uganda Research Unit on AIDS.
This so-called 'hygiene hypothesis' — namely that infections in childhood protect children from allergies in later life — originated in the developed world to explain the increase of allergies with improved hygiene and healthcare standards.
The trade-off between curing diseases and increasing allergy risk now seems to have reached the developing world.
"A number of studies have shown that allergy is on the increase in both the developed and developing world, but the exact cause of this increase is still unknown in the developing world," Mpairwe said.
Zac Kakyama Serubidde, a family physician at the Louise Memorial Medical Center, Uganda, said the study raises a moral question about whether to treat the women's worm infection and risk the baby having a skin infection, or to not treat and risk the mother dying from anaemia.
"You cannot let a mother die of anaemia because you want to protect the child in the womb from skin infections like eczema, which has never killed anybody," he said. "I would not hesitate to de-worm an expectant mother and I feel that this is the message that should be passed on to all health workers."
"In Sub-Saharan Africa, the commonest causes of anaemia in the general population are parasitic or worm infestation," he added.
Mpairwe said: "It would be important to replicate these results in other settings and understand the underlying mechanisms before any policy change recommendations can be made."
When all the evidence is available, she said, it would be possible to advise medical workers whether to delay worm treatment of mothers until after the birth or to de-worm during pregnancy, which is the current practice.
Pediatric Allergy and Immunology 10.1111/j.1399-3038.2010.01122.x (2011)