Grant CP-g-22-04.01 – Objective
The Grant CP-g-22-04.01 aims at providing: “support to Member States’ authorities to contribute to the setting and scaling up of this animal and environmental surveillance system, including the systematic ongoing collection of data by EFSA”. In particular, the main objective is “strengthening of a surveillance system for emerging and re-emerging pathogens in animals and the environment in Member States, taking into consideration neighbouring third countries of concern (e.g. Balkans, Mediterranean, Eastern Partnership) and possibly other third countries”.
Proposal Goal
Coherently with the general objective of the Grant, the goal of this proposal is the development of a surveillance system based on an ecological approach, able to take into account the whole spectrum of animal species in a given ecosystem (zoocenosis) having a possible role in the maintenance, persistence and/or transmission to humans of (re)emergent pathogens, already present or at risk of introduction into the national territory.
Integration with Existing Systems
The new surveillance system to set will be integrated with the already existing ones, in order to collect and complement the information recorded into the information systems currently used by the veterinary, environmental and public health sectors in Italy.
The Consortium, composed by the most relevant national and international reference centres, will put in place and manage “the coordination with the actions carried out on human health surveillance” in the country. Furthermore, it will establish a coordination mechanism “to ensure the regular exchange of knowledge, threats reporting, and joint undertaking of risk assessment between animal and human health surveillance experts at Union and Member State level”.
Surveillance Actions and Indicators
The proposed surveillance actions are conceived to produce the relevant and necessary information for the identification of proper early warning indicators and data for the risk assessment of the introduction or (re)emergence of selected zoonotic agents.
These indicators, coupled with environmental and climatic data, and animal/human demographic information, will support predicting models on the possible emergence, spread and persistence of those pathogens.
Pathogens Selection
Being Italy located in the middle of the Mediterranean Basin, and bordering some Central and Eastern European countries, a selection of pathogens – among those prioritised by EFSA – have been taken into consideration for the setting of the new surveillance system.
They are: Rift Valley Fever (RVF), Crimean-Congo haemorrhagic fever (CCHF), Q fever and other tick-borne diseases, like Lyme disease (LD) and Tick Borne Encephalitis (TBE), West Nile fever (WNF), Highly Pathogenic Avian Influenza (HPAI) E. granulosus s.l., infections by Hepatitis E virus (HEV) and Swine Influenza virus (SIV).
Furthermore, a specific survey schema is proposed to address the so-called Disease Y (a previously unseen and unknown disease of any animal species that can potentially spread among animals, potentially representing a threat for humans).
Rift Valley Fever (RVF)
Rift Valley fever (RVF) is a mosquito-borne disease, caused by an RNA virus belonging to the order Bunyavirales, family Phenuiviridae, genus Phlebovirus, affecting ruminants and humans. It represents a serious threat to human and animal health, as well as to the economy of several countries in Sub-Saharan Africa, where it can be considered endemic.
In the last decades, RVF has repeatedly demonstrated its ability to exit from its historically endemic areas. All available pieces of evidence, therefore, are clearly confirming this disease as one of the most threatening emerging zoonoses for countries in the Mediterranean Basin and the European Union (EU).
Among the possible pathways of RVF introduction into the EU, the dissemination of infected vectors from neighbouring countries may be considered relevant for a country like Italy. In this regard, EFSA, in a Scientific Opinion published in 2020 (1), recommends that: “Considering the possible future source of risk represented by the spread of infection into new areas closer to the EU borders, it is of paramount importance for the EU to establish and maintain a close collaboration with North African and Middle Eastern countries in the surveillance of possible introduction of RVF from currently infected areas, as well as to carefully monitor the evolution of the epidemics in African countries”.
The same approach has been followed in this project for RVF surveillance, targeting specific actions in Libya and in Mauritania, through the collaboration of the FAO sub-regional office of Tunis, which will be subcontracted for specific sampling activities.
CCHF and WNF Surveillance
Similarly, although it has been already defined the role of migratory birds in spreading CCHF and WNF viruses (2), a structured surveillance for early detecting the introduction of these pathogens into the national territory is still missing.
This is of paramount importance for CCHF, for which its capacity of colonizing new areas in Europa is well known (3), but also for the introduction of new variants and lineages of WNF.
Avian Influenza (HPAI)
Concerning other threats potentially posed by avian diseases, Highly Pathogenic Avian Influenza (HPAI) is on the top of list, given its capacity to rapidly mutate, also assuming genotypic characteristics able to be more efficiently transmitted across mammals.
Although, surveillance programmes for HPAI are already in place in the EU Member States (MS), targeting domestic and wild birds, the early detection of new HPAI incursions in waterfowl populations should be strengthened following innovative approaches, taking into consideration the habitats where these animals live.
In fact, it is essential to monitor wintering areas, especially those frequented by numerous waterfowl species that rely on shallow water habitats for feeding and resting. When a group of infected birds gathers in these water bodies, they can contaminate the surface water through their excrement, turning these water sources into highly effective means of spreading the infection.
Monitoring the water-filtering molluscs prevalence and distribution of the virus in wintering areas, especially in surface water, sediments, and fresh avian faeces can provide valuable information for predicting and preventing future outbreaks (4), as well as the survey on the avian-mammals interface, especially for those carnivores potentially predating the birds (e.g. foxes, wolves, mustelids, etc.) may allow early detection of potentially zoonotic strains.
Environmental Surveillance and WBE
Environmental surveillance is an important tool for monitoring the presence and spread of diseases in populations. The surveillance of diseases in the environment can provide early warning of outbreaks and help identify sources of contamination, as well as inform public health policy and intervention strategies.
Since the early beginnings of wastewater-based epidemiology (WBE) applied to poliovirus, environmental surveillance has been applied to several viral pathogens, specifically, to a range of waterborne enteric viruses such as non-polio enterovirus (i.e., coxsackieviruses, echoviruses), norovirus, adenovirus, rotaviruses, enterically transmitted hepatitis A and E viruses, and others. In recent years, WBE has also been successfully applied to non-enteric viruses, such as papillomavirus and polyomavirus.
In 2020, with the COVID-19 pandemic, WBE has further broadened its objectives to study respiratory viruses (5).
Environmental surveillance is also useful in the veterinary sector, particularly on farms where animals are kept in close proximity. Moreover, environmental surveillance can provide information regarding the occurrence and genetic diversity of pathogens in order to obtain a more in-depth insight into the phylogenetic relationships of strains circulating among animals and humans.
Domestic pigs are the primary reservoir for zoonotic HEV genotype 3, but more information is required on the origins and pathways of transmission within pig herds to establish measures to prevent further spread.
Blood or individual faecal samples are typically used to detect HEV on pig farms, but testing slurry is a practical, non-invasive, and cost-effective screening tool that can also provide samples suitable for sequencing.
Several studies have highlighted the presence of HEV in pig farming slurry, in different countries, including Italy (6).
Ecological Surveillance for Endemic Diseases
The same approaches, targeting the pathogens in the context of their ecological niches, may be more efficiently followed also for some diseases already present in part of the Italian territory, like some tickborne diseases (Q fever, LD, and TBE), and E. granulosus s.l. infestations in wild canids.
In fact, the application of proper surveillance and control activities in domestic animals cannot ignore the presence and interactions of these pathogen in wild populations and vectors, in their specific biological contexts.
Disease X and Disease Y
Disease X as defined by WHO is a serious international epidemic caused by Pathogen X, a pathogen currently unknown. Similarly, Disease Y is an emergent epizootic caused by Pathogen Y and can potentially spread among animals causing severe disease.
Increasing evidence shows a positive trend in the emergence of wildlife-associated RNA viruses in humans, as a consequence of direct transmission or after the initial infection of intermediate domestic animals.
The evolutionary potential of RNA viruses, linked to their high mutation rate, makes them prone to cross-species transmission and adapt to new hosts, thus probably presenting the greatest pandemic threats.
Among wildlife, we want to focus on rodents, bats and hedgehogs based on previous knowledge on the ecology of these mammals coupled with the evidence of circulation of viral pathogens of interest for animal and human health.
Rodents, Bats and Hedgehogs
Rodents are carriers of pathogens for livestock production (i.e. Swine dysentery, Aujeszky’s Disease, PCV2 and Encephalomyocarditis, Influenza A) and they also play a role in the epidemiology of leptospirosis and salmonellosis or in spreading antibiotic resistant bacterial strains such as livestock associated MRSA.
In addition, rodents have been recently demonstrated to play a significant role in the evolution of CoVs, in particular of those belonging to subgenus Embecovirus of genus Betacoronavirus. Recently, a novel species designated as Lucheng Rn rat coronavirus (LRNV) within the subgenus Luchacovirus (genus Alphacoronavirus) has been also described (7).
In recent years, many novel RNA viruses have been found in bats that are related to the emergence of Diseases X and Y both directly and as ancestors. In addition, surveillance efforts in this vast animal group, including more than 1400 species, revealed a wide variety of viruses whose zoonotic potential still needs to be elucidated.
Triggers of pathogens’ emergence from bats is worsen by the increasing ecological disturbances that affect bat populations, including loss of habitats, lack of food resources, chemical exposure to different toxic substances, that impose ecological pressures potentially increasing the likelihood of bats getting infected and shedding viruses.
Although recognized hotspots of emerging pathogens have been identified outside Europe, there is increasing evidence that viruses with zoonotic potential are circulating or emerging within European bats, including among others lyssaviruses, filoviruses, coronaviruses, astroviruses and mammalian orthoreoviruses.
Hedgehogs (Erinaceus europaeus) has been described as the host of a novel group (clade C) of Beta-CoVs (EriCoV). The Erinaceus coronavirus (EriCoV) species have been also described in other European countries in Erinaceus europaeus and also reported in China in Erinaceus amurensis.
Hedgehogs are widely spread in Europe and due to increasing urbanisation, are becoming more synanthropic living in areas closer to human and increasing the animal-human contact frequency exposing them to potential zoonotic pathogens as CoVs.
In addition, bats and hedgehogs, both hibernators and insectivores, share nocturnal habits posing a risk of cross-species transmission among animals.
