Italian network on NTDs (IN-NTD)

The list of 20 diseases and disease groups classified as Neglected Tropical Diseases (NTDs) by the World Health Organization (WHO) includes parasites (helminths, protozoa as well as ectoparasites), bacteria, viruses, fungi and toxins (https://www.who.int/teams/control-of-neglected-tropical-diseases/overview). While their impact is particularly heavy in Africa, Latin America and Asia, NTDs are nowadays seen with increasing frequency outside endemic regions, due to climate change, migrations and international travelling (Casulli, Reference Casulli2021). A symposium on NTDs was organized with the dual purpose of reviewing epidemiology of NTDs in Italy, with a focus on the parasitic infections currently or formerly endemic in Italy, and was also the occasion to present to a wider audience the ‘Italian network on NTDs’ (IN-NTD), a newly established coalition of institutions dedicated to fighting NTDs.

The manuscript by Casulli et al. (Reference Casulli, Antinori, Bartoloni, D'Amelio, Gabrielli, Gazzoli, Rinaldi and Bruschi2023) provides a global prospective on WHO and NTDs and an up-to-date overview of the most relevant parasitic endemic or imported NTDs in Italy (including soil-transmitted helminths, schistosomiasis, strongyloidiasis, cysticercosis, cystic echinococcosis, Chagas disease and leishmaniasis).

Current public health interventions to combat NTDs face major challenges that can only be overcome through networking at the national and international levels. As an example, WHO encourages its collaborating centres to work more closely together to ensure the translation of research-based evidence into policy, practice and public health advancements. Based on these assumptions, the IN-NTD was established as an alliance of scientific societies (including SoIPa), institutes, foundations, universities and non-profit organizations united to fight NTDs at the national and international levels. The aim of the network is to coordinate the work of many in order to achieve the necessary synergy and authority to propose and organize useful actions to combat NTDs in Italy, as well as in the countries where NTDs are endemic through various tasks such as advocacy, training, research, international public health cooperation and sustainable development goals (Casulli et al., Reference Casulli, Antinori, Bartoloni, D'Amelio, Gabrielli, Gazzoli, Rinaldi and Bruschi2023).

Wildlife parasites and citizen science

The importance of parasites in changing ecosystems was discussed during the symposium dedicated to wildlife and health management from a European perspective. Particular emphasis was given to the zoonotic parasites of wildlife, the interface between wildlife and livestock and the need for innovative approaches to harmonize wildlife population monitoring and disease health surveillance that engage the public. To this end, the citizen science approach, i.e. the collaboration of citizens in science, has allowed large-scale and cost-effective research in the field of zoonotic parasites of wildlife in recent years (Doherty et al., Reference Doherty, Filion, Bennett, Raj Bhattarai, Chai, de Angeli Dutra, Donlon, Jorge, Milotic, Park, Sabadel, Thomas and Poulin2021). Incorporating citizen science into wildlife health surveillance can be beneficial, especially when resources are limited and cost-effectiveness is paramount (Lawson et al., Reference Lawson, Petrovan and Cunningham2015). The importance and advantages of citizen science is underlined in the paper of this SI dealing with wildlife and their role in the circulation of arthropods and vector-borne agents of zoonotic relevance (Sgroi et al., Reference Sgroi, D'Alessio, Vada, Ferroglio, Vicente and Veneziano2023).

Innovative approaches to the study of parasites in exotic wildlife are also the main theme of another article in this SI, dealing with gastrointestinal parasites in captive olive baboons at Knowsley Safari Park in Merseyside, northwest England (Juhasz et al., Reference Juhasz, Spiers, Tinsley, Chapman, Shaw, Head, Cunningham, Archer, Jones, Haines, Walsh, Johnson, Quayle, Jones, LaCourse, Cracknell and Stothard2023). Fecal samples of baboons were collected from vehicles and sleeping areas, and video analysis of baboon–vehicle interactions was conducted during the study. The results showed the presence of the soil transmitted helminth parasites Trichuris trichura (48.0%) and Strongyloides fuelleborni (13.7%). The implications of these parasitological findings are discussed in terms of animal, keeper and public health, pointing to the need for a One Health approach in the control of neglected parasitic diseases.

Comparing approaches to parasitological issues

Two symposia are represented in this section. The comparison of different approaches to parasite control in different species and close relatives is emerging as a narrative thread in research lines in Italy and abroad. One symposium focused on comparing epidemiological aspects and strategies of parasite control in phylogenetically close species, such as horse and donkey, cattle and buffalo, cats and wild cats, humans and non-human primates. The comparative approach, if systematically applied on the basis of sound and evidence-based knowledge, helps in the identification of inappropriate approaches to 1 species (usually the less common or economically relevant) because of incautious knowledge transfer from the other species. The importance of these types of studies and topics is underlined in this SI through the example of horse and donkey parasitology (Buono et al., Reference Buono, Veneziano, Veronesi and Molento2023). Although these 2 host species can be infected by a similar range of parasites, they have important differences in the physiological response (i.e. donkeys typically show fewer clinical signs than horses, when heavily infected) and in drug pharmacokinetics (i.e. donkeys may require higher concentrations or shorter dosing intervals than horses). As a consequence, different thresholds (e.g. in terms of egg output for strongyles) and different drug dosages should be applied in the 2 animal species, calling for specific studies and knowledge for each of the 2 hosts.

From another perspective, a systematic and transversal comparison of parasite control practices promoted by different research groups in different geographical contexts can support the identification of strengths and weaknesses of each approach, leading to the fine-tuning of best practices and common guidelines. Comparison of control strategies for the most prevalent and economically important parasites of ruminants (i.e. gastrointestinal helminths) was the objective of another symposium held during the congress. The usefulness of comparing and discussing control practices has already been demonstrated at the European level through different collaborative projects (Charlier et al., Reference Charlier, Bartley, Sotiraki, Martinez-Valladares, Claerebout, von Samson-Himmelstjerna, Thamsborg, Hoste, Morgan and Rinaldi2022), however this exercise is still lacking at the national level. The Italian perspective on the control of gastrointestinal helminth infections was deeply analysed during the symposium and subsequently reported in this SI (Maurizio et al., Reference Maurizio, Perrucci, Tamponi, Scala, Cassini, Rinaldi and Bosco2023). The work includes a nationwide epidemiological update on parasite prevalence and on the possible emergence of anthelmintic resistance. The outcomes of this review represent an interesting point of view for other Mediterranean countries, where similar management systems and overlapping climatic conditions are found.

In both papers, the in-depth analysis of current practices and common knowledge leads to the identification of misbeliefs and inappropriate practices, and contributes to build the right approach on an evidence-based knowledge. These 2 manuscripts are highly relevant for the real world of the veterinary profession and farm advisors, aiming to change the attitude of farmers and veterinary practitioners, towards a species-specific approach to helminth control, integrating the intelligent use of chemical drugs with the adoption of alternative practices.

Unusual perspectives on the role of parasites

Parasites constitute a substantial proportion of the biotic component in all ecosystems, in terms of both number of species and biomass. Notwithstanding their important ecological role, parasites are rarely considered in environmental conservation programs and their risk of extinction is often neglected (Lymbery and Smit, Reference Lymbery and Smit2023). Two symposia of this Congress shared this unusual perspective on parasites, investigating how extreme events or long-term changes in the ecosystem, both natural and anthropogenic in origin, can impact parasite population dynamics.

The first symposium focused on the marine ecosystem and more specifically on the Mediterranean Sea, which is significantly affected by anthropogenic stressors, such as fish resource overexploitation, maritime transport and land-based pollutants/contaminants (Mandić and Piraino, Reference Mandić and Piraino2023), as well as by the fast increase of water temperature and climate change. The Mediterranean Sea represents a hotspot of marine biodiversity, with complex networks and trophic chains in which different animal species, encompassing a multitude of taxa and phyla, found themselves interlaced and inter-dependant. Trophically transmitted helminths are associated to these trophic chains, having organisms in higher trophic-levels as definitive hosts. These parasites are indirectly impacted by ecosystem perturbations that may affect their intermediate, paratenic or definitive hosts, since they require stable food webs to complete successfully their life cycles. As a consequence, these helminths may serve as sentinels of the status of Mediterranean ecosystem, and the study of their host–parasite relationships can provide measurable indicators for monitoring the magnitude of anthropogenic impact on the environment. Specific examples are provided in the review by Palomba et al. (Reference Palomba, Marchiori, Tedesco, Fioravanti, Marcer, Gustinelli, Aco-Alburqueque, Belli, Canestrelli, Santoro, Cipriani and Mattiucci2023) of this SI, which developed the discussion held during the Symposium.

The second symposium dealing with this topic investigated how extreme weather events such as floodings, droughts and fires impact on parasite diffusion and transmission risks. These catastrophic events are increasing in frequency and intensity worldwide due to global warming, however the Mediterranean basin, including Italy, is considered a hot spot of climate change consequences (MedECC, 2020). The paper by Poglayen et al. (Reference Poglayen, Gelati, Scala, Naitana, Musella, Nocerino, Cringoli, Frangipane di Regalbono and Habluetzel2023) summarises the main findings of the impact of 6 catastrophic events that occurred in Italy between 1976 and 2021, concluding with a few suggestions based on the lessons learned from the management of the above-mentioned events. Floodings can obviously facilitate the wide diffusion of environmental stages of waterborne protozoa (e.g. cysts of Giardia intestinalis, oocysts of Cryptosporidium spp. and Toxoplasma gondii) and other water- and soil-borne helminthic parasites (e.g. Fasciola hepatica) leading to possible epidemics, as evidenced by outbreaks recorded in Sardinia. By contrast, fires and droughts normally lead to a reduction of propagation forms (e.g. oocysts, larvae) and intermediate hosts (oribatid mites, xerophilous gastropod mollusks) and vectors (ixodid tick environmental stages), suggesting a beneficial (or cost) effect for the hosts. However, fires cause soil hydrophobicity increasing the risk of subsequent floodings through heavy rainfalls, and both events may influence movements, distribution and management practices for animals kept extensively (due to emergency reasons), leading to unexpected changes in parasite burdens or to the re-emergence and spread of parasitic diseases. Regular monitoring of the parasitological status of these animals can prevent clinical outcomes. The authors are therefore promoting a broader discussion about the so-called ‘disaster parasitology’, enlarging to a global scale the need for experience sharing, in order to guide priorities in the prevention and control of the parasitological implications of these catastrophic events. Finally, the use of geospatial technologies (Rinaldi and Cringoli, Reference Rinaldi and Cringoli2014), associated with new electronic devices, such as drones and data loggers, is reported as a useful tool in the assessment of climate change and extreme event impacts on parasite transmission.