Haemophilus ducreyi is an emerging cause of tropical ulcers

The bacterium Haemophilus ducreyi was the causative agent of chancroid, a genital ulcer disease that has practically disappeared over the last years. However, this pathogen has emerged as a frequent cause of chronic skin ulcers among children in developing countries. These are the conclusions of a study on the global epidemiology of H. ducreyi infections, led by Oriol Mitjà, researcher at ISGlobal and Camila González-Beiras, student of the ISGlobal Master of Global Health, and published in Emerging Infectious Diseases, one of the main journals in the field.

Children living in the developing world often suffer from skin infections due to the lack of hygiene measures. The so-called neglected skin diseases (for example yaws, leprosy, Buruli ulcer, scabies and filariasis) are among the leading causes of disease in tropical regions, with high levels of incapacity and mortality.

The current epidemiology of genital and skin ulcers caused by H. ducreyi is poorly documented, since the pathogen can only be identified by molecular or culture methods that are performed in a few specialized laboratories in developed countries. In order to better understand the epidemiology of H. ducreyi, the researchers performed a systematic review of published data on genital and skin ulcers caused by this bacterium.

Using data from 49 publications, the study draws two main conclusions: the first one is that there has been a global sustained reduction in the proportion of genital ulcers caused by infection with H. ducreyi. For example, in Botswana, Kenya or South Africa, the percentage of genital ulcers caused by H. ducreyi decreased from 25-70% to negligible levels (0-1%). This global trend is due to the combined use of antibiotics recommended by WHO and to changes in social behaviour such as the use of condoms.

The second conclusion of the study is the confirmation that H. ducreyi is a frequent cause of tropical skin ulcers among children from developing countries. Almost half of the patients with skin ulcers in West Africa and the Pacific Islands were infected by H. ducreyi.

The authors argue that new strategies are needed to control this epidemic. Recent studies have proven the efficacy of water and soap in reducing skin diseases. "It is highly likely that improving hygiene, together with a massive antibiotic treatment similar to what is done for yaws, will be the most effective way of tackling ulcers caused by H. ducreyi", concludes Dr. Mitjà.

Reference:

González-Beiras C, Marks M, Chen CY, Roberts S, Mitjà O. Epidemiology of Haemophilus ducreyi Infections. Emerg Infect Dis. 2016 Jan;22(1).

Image: CDC/Dr. W.A. Clark