Scabies, impetigo often neglected in resource-poor settings

By C. Vidya Shankar MD

NEW YORK (Reuters Health) - Despite a worldwide prevalence of 100 million cases in 2010, scabies is "neglected" both in terms of coordinated control programs and research, researchers say.

The prevalence of scabies is highest in the Pacific Islands, Panama, and indigenous communities of Australia, they found in a systematic review published online June 26 in the Lancet Infectious Diseases.

"The high prevalence in these countries might be due to low socioeconomic status, with resulting domestic crowding, but it might also be because scabies is inherently more suited to a tropical environment," Dr. Lucia Romani, from the University of New South Wales, Sydney, Australia, and colleagues explained.

Scabies is a contagious skin infection caused by Sarcoptes scabiei mites burrowing into the skin. It presents with intense nocturnal pruritus and is complicated by secondary bacterial infected skin, the researchers wrote.

The reviewers searched common databases from 1985 to 2014 for scabies and impetigo and included all population-based prevalence studies, while excluding review articles and institutional surveys. After screening 2409 reports they identified 48 articles to include in their analysis.

Overall, the studies were of poor quality, the researchers said. Diagnostic criteria were rarely used and most studies were restricted to high-prevalence countries. Only four reports scored satisfactorily in all of their five quality standards.

The researchers encountered large variations in sample size - from 18,000 people surveyed in Vanuatu to only 56 from Papua New Guinea.

Overall, the highest prevalences of scabies were in Papua New Guinea (71%), Panama (32%), Fiji (32%), and Aboriginal populations of Australia (30%). Impetigo was most prevalent among Australian Aboriginal population (49%), Solomon Islands (43%), Brazil (20%), and Fiji (20%), they noted.

The disease burden was higher among children, the researchers noted. The prevalence of childhood scabies was highest in Panama (78%), Fiji (44%) and among Australian Aborigines (35%), while impetigo was most common among Australian Aborigines (69%), in Solomon Islands (52%), and Fiji (36%).

Underdiagnosis of scabies and overestimation of impetigo prevalence may explain the weak correlation between the prevalence of scabies and impetigo in their study, the researchers postulated.

Scabies is often "under-recognized", they warn. They recommended larger age-stratified prevalence studies, standardized diagnostic and treatment protocols, and further research on mass drug administration for control of scabies.

The authors were not available for comment.

SOURCE: http://bit.ly/1KmUA8T

Lancet Infect Dis 2015.

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