Infectious diseases

2021 World Neglected Tropical Diseases Day

The second World Neglected Tropical Diseases (NTDs) Day will be held on 30 January 2021. To mark the occasion, on January 28, the World Health Organization (WHO) will launch its roadmap for NTDs for the period 2021-2030, which is aimed at increasing prevention and control of these too-long neglected diseases.

What are NTDs?

Based on the WHO definition, they are a heterogeneous group of (currently) twenty diseases, many of them infectious, caused by viruses, bacteria, parasites, fungi and toxins:

• Buruli ulcer
• Chagas disease (American trypanosomiasis)
• Dengue
• Dracunculiasis (Guinea-worm disease)
• Cystic and alveolar echinococcosis
• Foodborne trematode infections
• Human African trypanosomiasis (sleeping sickness)
• Leishmaniasis
• Leprosy (Hansen’s disease)
• Lymphatic filariasis
• Mycetoma, chromoblastomycosis and other deep mycoses
• Onchocerciasis (river blindness)
• Rabies
• Scabies and other ectoparasitoses
• Schistosomiasis (Bilharzia)
• Soil-transmitted helminthiases
• Taeniasis and cysticercosis
• Trachoma
• Yaws (endemic treponematoses)
• Snakebite envenoming

Who is affected?

NTDs affect more than one billion people worldwide, causing over half a million deaths each year. They are particularly common in poor and marginalized populations, especially in rural areas where healthcare resources are limited.

These diseases are usually chronic and disabling and are frequently associated with social stigma and exclusion. Indeed, they are responsible for synergistic epidemics that exacerbate the social and health conditions of affected populations, thus perpetuating cycles of infection and poverty and limiting the prospects of development for entire communities.

Despite being highly prevalent in tropical and subtropical regions, NTDs occur throughout the world. Human migration, international travel, movements of animals, international marketing of food products and climate change are all contributing factors to the spread and increased competence of insects as vectors, and mammals and birds as hosts, for the relevant pathogens.

The situation in Italy

A survey carried out in our country identified 4132 cases of NTDs in nine sentinel centres, between 2011 and 2017. Schistosomiasis, strongyloidiasis (soil-transmitted helminthiasis) and Chagas disease accounted for most of the cases, which included also cysticercosis, scabies, filariasis, leishmaniasis and cystic echinococcosis. Another survey revealed the presence of other NTDs in Italy, such as trachoma, onchocerciasis, leprosy and, more recently, opisthorchiasis (foodborne trematode infection), chikungunya and dengue.

Some of these NTDs are traditionally endemic in Italy, due to the presence of competent vectors (blood-feeding Diptera, phlebotomus sandfly) for leishmaniasis and intermediate and definitive mammal hosts (sheep and herding dogs) for cystic echinococcosis. In particular, cystic echinococcosis (a zoonotic parasitic disease) is the most significant NTD in Italy, with an average incidence rate of about 15 cases/1,000,000 population in the period 2009-2013. It also accounted for about 21,000 hospital discharges between 2001 and 2014.

WHO roadmap and ISS commitment

The WHO 2021-2030 roadmap has four main objectives:

• Reducing the number of people requiring interventions against NTDs by 90%
• Reducing disability-adjusted life years (DALYs) by 75%
• Eliminating at least one NTD in 100 countries
• Eradicating at least two NTDs worldwide (dracunculiasis and yaws).

Through the “Centro di Collaborazione OMS ITA-107” (WHO Collaborating Centre for the Epidemiology, Detection and Control of Cystic and Alveolar Echinococcosis) and the Unit of Foodborne and Neglected Parasitic Diseases of its Department of Infectious Diseases, the ISS has long been at the forefront of international public health efforts to fight cystic and alveolar echinococcosis. Between 2014 and 2015, the ISS conducted the world’s largest population-based ultrasound study of cystic echinococcosis, recruiting (with informed consent) 25,000 people from rural areas of Romania, Bulgaria and Turkey. The prevalence levels recorded in this cross-sectional study made it possible to estimate cases of infection with cystic echinococcosis in the rural areas of these 3 countries at over 151,000, about one third of them with cysts in the active phase. The ISS also launched an international surveillance system for the establishment of a clinical register, ERCE, which currently includes over 2,000 patients recruited by 44 centres in 15 countries (Albania, Austria, Bangladesh, Bulgaria, France, Georgia, Hungary, Iran, Italia, Kazakhstan, Poland, Romania, Russia, Spain and Turkey). As no randomized clinical trials have yet been published in the international scientific literature, ERCE aims to prospectively answer specific clinical questions about patient management.

The ISS holds an international patent for drugs against helminthic NTDs (Salts of compounds having a benzimidazolic structure), and is engaged in the research and identification of biomarkers for cystic echinococcosis. In addition, it is currently involved in the coordination of several international projects aimed at developing multicentre studies on the clinical and molecular epidemiology of cystic and alveolar echinococcosis, including MEmE (One Health EJP, Horizon 2020) and PERITAS (EULAC-Health).