Life Starting from scratch, doctors beat the tropical curse of scabies

Starting from scratch, doctors beat the tropical curse of scabies

A team of researchers have made a breakthrough in eradicating scabies and impetigo in the Solomon Islands. Photo: Getty
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If a strange silence has come over the Choiseul Province of the Solomon Islands, it’s because thousands of people have stopped scratching.

Australian, Solomon Islands and British researchers have wiped out 90 per cent of scabies and 74 per cent of impetigo (known as ‘school sores’ in children) from the province in a study that offered the entire population – more than 26,000 people – a single round of treatment for these closely linked, highly infectious diseases.

It was the largest study ever conducted on the control of scabies, which affects hundreds of millions of people, mainly in developing countries – and which, in 2017, the World Health Organisation recognised as a neglected tropical disease.

Scabies is especially rife in in rural and remote communities where access to treatment is lacking and domestic overcrowding is common – and that includes in many indigenous Australian communities.

A team of researchers from Telethon Kids Institute in 2017 found that up to 45 per cent of indigenous Australian children have school sores at any given time.

How the trial worked

As the researchers describe in their paper, scabies is caused by skin infestation with the arthropod mite, Sarcoptes scabiei.

It brings on an intense inflammation with itching that is frequently severe – and is often associated with bacterial skin infection caused by Staphylococcus aureus and Streptococcus pyogenes (impetigo).

This infection can in turn lead to severe complications including septicaemia, and increasing evidence supports a link to acute rheumatic fever and rheumatic heart disease.

Professor Andrew Steer is a paediatric infectious disease physician at the Royal Children’s Hospital in Melbourne, and Director of Infection and Immunity at Murdoch Children’s Research Institute.

Dr Speer told The New Daily the study was a carried out in tandem with the Solomon Island Ministry of Health.

“The ministry had made a commitment to work toward the eradication of trachoma (the leading infectious cause of blindness) by administering the antibiotic azithromycin. They had done this across all provinces except Choiseul,” he said.

The researchers worked with the ministry to also administer a drug called ivermectin, a broad anti-parasitic that has been safely used in billions of doses. (The scientists who discovered ivermectin won the Nobel Prize in 1915 because of its efficacy with river blindness as well as scabies.)

The study compared the prevalence of scabies and impetigo in residents of 10 randomly selected villages before and after the mass drug administration. The proportion of people with scabies and impetigo at the start of the study was 18.7 per cent and 24.8 per cent respectively.

One round of treatment of the antibiotic azithromycin (which has some affect on impetigo) and the anti-parasitic ivermectin was given to more than 95 per cent of the population.

According to a prepared statement: 1399 people had had their skin examined by the research team at the start of the MDA in 2015, with 261 having scabies and 347 having impetigo.

Twelve months after the mass dose, the researchers returned and 1261 people were examined: 29 people with scabies, a decrease of 88 per cent, and 81 with impetigo, a decrease of 74 per cent.

According to the Solomon Islands Ministry of Health, there were almost 6000 fewer people overall presenting to outpatient clinics – a decrease of 36.1 per cent, in the three months after the mass dose. Presentations for skin sores, boils and abscesses fell by 50.9 per cent.

Dr Steer said significant reductions were also seen in local clinic attendance for acute respiratory infections and diarrhoeal disease.

The drug ivermectin is emerging as the great hope. Dr Steer said when ivermectin is used alone – that is, without an antibiotic – about two thirds of impetigo goes away.

The research was a collaboration between the Murdoch Children’s Research Institute (MCRI), the Kirby Institute at UNSW Sydney, the Solomon Islands Ministry of Health and Medical Services, and the London School of Hygiene and Tropical Medicine.

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