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The “Digital Earth” (DE) metaphor is very useful for both end users and hydrological modelers (i.e., the coders). In this opinion paper, we analyze different categories of models with the view of making them part of Digital eARth Twin Hydrology systems (DARTHs). We stress the idea that DARTHs are not models, rather they are an appropriate infrastructure that hosts (certain types of) models and provides some basic services for connecting to input data. We also argue that a modeling-by-component strategy is the right one for accomplishing the requirements of the DE. Five technological steps are envisioned to move from the current state of the art of modeling. In step 1, models are decomposed into interacting modules with, for instance, the agnostic parts dealing with inputs and outputs separated from the model-specific parts that contain the algorithms. In steps 2 to 4, the appropriate software layers are added to gain transparent model execution in the cloud, independently of the hardware and the operating system of computer, without human intervention. Finally, step 5 allows models to be selected as if they were interchangeable with others without giving deceptive answers. This step includes the use of hypothesis testing, the inclusion of error of estimates, the adoption of literate programming and guidelines to obtain informative clean code. The urgency for DARTHs to be open source is supported here in light of the open-science movement and its ideas. Therefore, it is argued that DARTHs must promote a new participatory way of performing hydrological science, in which researchers can contribute cooperatively to characterize and control model outcomes in various territories. Finally, three enabling technologies are also discussed in the context of DARTHs – Earth observations (EOs), high-performance computing (HPC) and machine learning (ML) – as well as how these technologies can be integrated in the overall system to both boost the research activity of scientists and generate knowledge.

The understating of the dynamics of tracers and water transit times at catchment scale has increasingly grown in the last decades, becoming a consolidated approach in the field of hydrological and ecohydrological research. Recently, a benchmark contribution has been given in the work by Benettin et al. (2022), which reviews the state of art on the topic, also addressing present and future challenge, pointing out some open questions in transit time research. This commentary tries to contextualize the above article, highlighting the most focal points and relating it to a broader context in the field. A brief overview on the main concepts of backward transit times, StorAge selection functions and forward transit time distributions is given in a logical-historical order, giving to the reader the primary instruments for a later comprehensive understating of the Transit Time Theory. Eventually, a numerical example helps to clarify the above concepts in a very simple and effective way.

This questionnaire was presented to support the opinion paper \textit{Rigon, R., Formetta, G., Bancheri, M., Tubini, N., D'Amato, C., David, O., & Massari, C. (2022). HESS Opinions: Participatory Digital Earth Twin Hydrology systems (DARTHs) for everyone: a blueprint for hydrologists. Hydrology and Earth System Sciences Discussions, 1-38.

This contribution illustrates the GEOframe Soil Plant Atmosphere Continuum Estimator (GEOSPACE). It is the ecohydrological model of the GEOframe system and it wants to simulate the soil-vegetation-atmosphere interactions to study and analyze the complex processes that occur in the Earth Critical Zone (CZ). The CZ is defined as the “heterogeneous, near surface environment in which complex interactions involving rock, soil, water, air, and living organism regulate the natural habitat and determine the availability of life-sustaining resources”.GEOSPACE is a coupled model in which the three major components are WHETGEO, GEO-ET and BrokerGEO. WHETGEO, Water Heat and Transport in GEOframe, (Tubini N. and Rigon R., 2021), solves the conservative form of Richardson-Richards equation using the Newton-Casulli-Zanolli algorithm (Casulli V. and Zanolli P., 2010) that guarantees the convergence at any time step, and the proper transition from unsaturated condition to saturated one. Besides it deals seamlessly the surface water ponding. WHETGEO also implements the numerical solution shown in Casulli and Zanolli (2005) to solve the advection-dispersion equation and describe the solute transport. GEO-ET, EvapoTranspiration in GEOframe, computes evapotranspiration according to three different formulations, the Priestley-Taylor model, Penman FAO model and GEOframe-Prospero model (Bottazzi, 2020), by considering Jarvis model (Macfarlane et al., 2004) and Ball-Berry-Leuning model (Lin et al., 2015) to compute environmental and water stress factors. BrokerGEO is the coupler component that allow the exchange of data between the other two components in memory and considers the root water uptake for the computation of the actual evapotranspiration. The GEOSPACE model was tested with the lysimeter of the “Spike II” experiment (Nehemy et al., 2019; Benettin et al., 2021) of the Ecole Polytechnic Federal de Lausanne. The analysis we carried out with GEOSPACE concern the flux partitioning of precipitation and irrigation water into evaporation and transpiration; the soil water and groundwater storage; the transport of water stable isotopes through the soil. In this research we present them and show how GEOSPACE can be used to test hypotheses on the links between the plant water status and its isotopic signatures.GEOSPACE is developed in Java using the Object-Oriented programming paradigm and it is completely open source, available on the GEOframe GitHub website. The code organization and its functionalities besides solving the hydrological issues are designed according to principle of open science to be inspectable and verified by third parties.

The Digital Earth (DE) metaphor is very useful for both end users and for hydrological modellers. However, in literature it can promote the erroneous view of models as a commodity, that is a basic good used in commerce that is interchangeable with other goods of the same type, without any warning about the fact that some models work better than others, some models just work while others can be simply wrong. These distinctions are at the core of doing good science. This opinion contribution, on the one hand, tries to accept the challenge of adopting models as commodities but, on the other, it wants to show that this acceptance comes with some consequences as to how models must be structured. The first reuirement is that Digital eARth Twin Hydrology system (called DARTH) need to be Open Source and built with Open Science rules in mind. We analyse different categories of models, with the view of making them part of a . We also stress the idea that DARTHs are not models in and of themselves, rather they need to be built on an appropriate infrastructure that provides some basic services for connection to input data and allows for a modelling-by-components strategy, which, we argue, is the right one for accomplishing the requirements of the DE. The need to tie predictions to an estimated confidence interval is also supported. Finally, it is argued that DARTHs must promote a new participatory way of doing hydrological science, where researchers can contribute cooperatively to characterize and control model outcomes in various territories. Furthermore, this has consequences for the engineering of the systems.

Objectives From the authors’ experience, the consumption of a balanced prescription home-prepared diet that includes zucchini (courgette) benefits cats with recurrent urolithiasis, but there is no published evidence to support this. The aim was to study the effects on urinary parameters of (1) a balanced prescription home-prepared diet containing zucchini, and (2) the addition of zucchini to a dry food, compared with two commercial therapeutic diets. Methods Eight healthy cats were included in a Latin-square designed protocol. Five diets were evaluated: two commercial diets, designed for cats with urinary disorders, one high-moisture (U-WET) and one high-sodium dry (U-DRY); one home-prepared diet (HOME); one commercial dry food for adult maintenance (DRY); and DRY given together with 10 g of zucchini per kg body weight (DRY-Zuc). After a 7-day adaptation period, urine was collected and daily food and water intakes were assessed for 12 days. Urinary parameters, and relative supersaturation (RSS) for calcium oxalate (CaOx) and struvite, were determined. Data underwent repeated measures ANOVA analysis. Results The digestibility of energy, dry matter, protein and fat was highest with the HOME diet. CaOx RSS was lowest in cats eating the HOME diet, but not significantly different from the U-WET or U-DRY diets. CaOx RSS was lower in cats eating the DRY-Zuc diet than in cats eating the DRY diet. Struvite RSS did not differ significantly among groups. Conclusions and relevance This study shows that a balanced prescription home-prepared diet was safe and allowed a very low urinary CaOx RSS. It also showed that adding zucchini to dry food lowered the urine CaOx RSS.

The Italian initiative WATZON (WATer mixing in the critical ZONe) is a network of instrumented sites, bringing together six pre-existing long-term research observatories monitoring different compartments of the Critical Zone - the Earth's permeable near-surface layer from the tops of the trees to the bottom of the groundwater. These observatories cover different climatic and physiographic characteristics over the country, providing information over a climate and eco-hydrologic transect connecting the Mediterranean to the Alps. With specific initial scientific questions, monitoring strategies, databases, and modeling activities, the WATZON observatories and sites is well representative of the heterogeneity of the critical zone and of the scientific communities studying it. Despite this diversity, all WATZON sites share a common eco-hydrologic monitoring and modelling program with three main objectives:1) assessing the description of water mixing process across the critical zone by using integrated high-resolution isotopic, geophysical and hydrometeorological measurements from point to catchment scale, under different physiographic conditions and climate forcing;2) testing water exchange mechanisms between subsurface reservoirs and vegetation, and assessing ecohydrological dynamics in different environments by coupling the high-resolution data set from different critical zone study sites of the initiative with advanced ecohydrological models at multiple spatial scales;3) developing a process-based conceptual framework of ecohydrological processes in the critical zone to translate scientific knowledge into evidence to support policy and management decisions concerning water and land use in forested and agricultural ecosystems.This work provides an overview of the WATZON network, its objectives, scientific questions, and data management, with a specific focus on existing initiatives for linking data and models based on WATZON data.

The scope of this work is to present new insights of the GEOframe system. GEOframe is an open-source, semi-distributed, component-based hydrological modeling system. It is developed in Java and in Python and based on the environmental modeling framework Object Modeling System V3 (OMS3). Each part of the hydrological cycle is implemented in a self-contained building block, commonly called component. Components can be joined together to obtain multiple modeling solutions that can accomplish from simple to very complicated tasks. More than 50 components are available for the estimation of all the variables of the hydrological cycle. Starting from the geomorphic and DEM analyses, GEOframe allows the spatial interpolation of the meteorological forcing data, the simulation of the radiation budget, the estimation of the ET and of the snow processes. Runoff production is performed by using the Embedded Reservoir Model (ERM) or a combination of its reservoirs. Model parameters can be calibrated using two algorithms and several objective functions. The graph-based structure, called NET3, is employed for the management of process simulations. NET3 is designed using a river network/graph structure analogy, where each HRU is a node of the graph, and the channel links are the connections between the nodes. In any NET3 node, a different modeling solution can be implemented and nodes (HRUs or channels) can be connected or disconnected at run time through scripting. Thanks to its solid informatics infrastructure and physical base, GEOframe proved a great flexibility and a great robustness in several applications, from small to big scale catchments. GEOframe is open source, is chain of development is based on open source products, and its codes are engineered to be inspectionable. This because it helps the reproducibility and replicability of research. Developers and users can easily collaborate, share documentation, and archive examples and data within the GEOframe community. We believe that these are a priori condition to verify the reliability and the robustness of models. GEOframe modular structure allows for the fair comparison of model structure units and algorithms implementations because just the component performing that specific task has to be changed. In this contribution we list the components available and discuss some applications at different scales whit different modeling tools which return what we think realistic results. We show that there exist no perfect model of a process but that the modelling art and science can be made more evolutionary even when they are revolutionary.

Measuring and modelling of water and solute fluxes in the Critical Zone across soil-vegetation-atmosphere system is nowadays a very important challenge because of the complexity of both soil and plants. Considering the one-dimensional problem, we implement a virtual lysimeter model, LysimeterGEO, in which we coupled infiltration and evapotranspiration by using stress factor (Jarvis, 1976; Ball et al., 1987), with which we can compute effective evapotranspiration and remove it from Richards’ equation balance (Casulli and Zanolli, 2010).As regards the IT implementation, LysimeterGEO is a system of components built upon the Object Modelling System v3 (OMS3). The infiltration component of the virtual lysimeter is WHETGEO 1D - Water, Heat and Transport in GEOframe (Tubini N. 2021), which solves the mass and energy balance for the one-dimensional case. The mass balance is represented by the Richards equation and the non-linear system is solved using the nested Newton algorithm (Casulli and Zanolli, 2010). Evapotranspiration flows are instead estimated using the GEOframe-Prospero model (Bottazzi M. 2020) which estimates the effective transpiration through the equilibrium temperature of the canopy as a function of the stomatal conductance. Finally, the transpiration is calculated starting from the method of Schymanski and Or (2017) and modified by including the dependence on the transpiring surface, the model of conductance of the stomata, as well as the conservation of mass. In LysimeterGEO the interaction between infiltration and evapotranspiration is made possible by BrokerGEO component (D’Amato C. 2021), which computes the water stress factor for vegetation by using Jarvis or Ball-Berry model. BrokerGEO computes the water stress factor considering the water content information by WHETGEO in each control volumes of the soil column discretization. Moreover, it computes a representative water stress factor for the whole column of soil for the evapotranspiration component. Finally, the density root distribution is considered to remove water into the soil used for evapotranspiration flows.The modelling of water and solute fluxes across soil-vegetation-atmosphere is made possible by implementation of travel times of waters within vegetation, the growing of the roots and in general the growing of the plants. The idea of a joint infiltration-evapotranspiration model allows us to investigate also problems related to radical growth and the different effect of roots on vegetation. Furthermore, the implementation of travel times on a vegetation scale allows a careful analysis of the behaviour of the same as the soil moisture conditions vary.

It is known that measuring and modeling of water and solute fluxes across soil-plant-atmosphere is nowadays a very important challenge because of the complexity of both soil and plants. In particular evapotranspiration (Schymanski and Or, 2017) is related with radiation, temperature, relative humidity, wind but it depends also by the water content in soil. Specifically, the water content varies with precipitation and with the water properties of soil, soil water retention curves and soil hydraulic conductivity. To consider the effects of water content on the rate of evapotranspiration it is necessary to study infiltration and evapotranspiration processes and find a physical, but also, a modelling point of view to coupled these processes. Considering the 1D problem we implement a virtual lysimeter model in which we coupled infiltration and evapotranspiration by using stress factor (Collatz at all, 1991), with which we can compute effective evapotranspiration and remove it from Richards’ equation balance (Casulli and Zanolli, 2010). In addition, the modeling of water and solute fluxes across soil-plant-atmosphere is made possible by implementation of travel times of waters within vegetation, the growing of the roots and in general the growing of the plants. Casulli e Zanolli, 2010. A Nested Newton-type algorithm for finite volume methods solving Richards’ equation in mixed form. SIAM J. SCI. COMPUT. Vol. 32, No. 4, pp. 2255–2273.G. James Collatz, J. Timothy Ball, Cyril Grivet and Joseph A. Berry, 1991. Physiological and environmental regulation of stomatal conductance, photosynthesis and transpiration: a model that includes a laminar boundary layer. Agricultural and Forest Meteorology, Vol. 54, pp. 107-136.P.M. Cox, C. Huntingford, R.J. Harding, 1998. A canopy conductance and photosynthesis model for use in a GCM land surface scheme. Journal of Hydrology 212–213, 79–94.Jarvis, P.G., 1976. The interpretation of the variances in leaf water potential and stomatal conductance found in canopies in the field. Phil. Trans. Roy. Soc. Lond. B273, 593–610.Stanislaus J. Schymanski and Dani Or, 2017. Leaf-scale experiments reveal an important omission in the Penman–Monteith equation. Hydrol. Earth Syst. Sci., 21, 685–706.

Within the initiatives for poliomyelitis eradication by WHO, Italy activated an environmental surveillance (ES) in 2005. ES complements clinical Acute Flaccid Paralysis (AFP) surveillance for possible polio cases, detects poliovirus circulation in environmental sewage, and is used to monitor transmission in communities. In addition to polioviruses, the analyses comprised: (i) the monitoring of the presence of non-polio enteroviruses in sewage samples and (ii) the temporal and geographical distribution of the detected viruses. From 2009 to 2015, 2880 sewage samples were collected from eight cities participating in the surveillance. Overall, 1479 samples resulted positive for enteroviruses. No wild-type polioviruses were found, although four Sabin-like polioviruses were detected. The low degree of mutation found in the genomes of these four isolates suggests that these viruses have had a limited circulation in the population. All non-polio enteroviruses belonged to species B and the most frequent serotype was CV-B5, followed by CV-B4, E-11, E-6, E-7, CV-B3, and CV-B2. Variations in the frequency of different serotypes were also observed in different seasons and/or Italian areas. Environmental surveillance in Italy, as part of the 'WHO global polio eradication program', is a powerful tool to augment the polio surveillance and to investigate the silent circulation or the re-emergence of enteroviruses in the population.

Background Enterovirus infections can cause a variety of illnesses, ranging from asymptomatic infections to severe illness and death. Aim To support polio eradication activities, in February 2019, the WHO Regional Reference Laboratory for polio in Italy, at the National Institute of Public Health (Istituto Superiore di Sanita), promoted an investigation on non-polio enterovirus laboratory capacity, with the support of the Italian Ministry of Health. The aim was to collect data on the assays used routinely for diagnostic purposes and to characterize enterovirus outbreaks strains by sequence analysis of the Viral Protein 1 region. Methods A questionnaire was administered to public health laboratories through all Italian Regions for 2018 and subsequently, an electronic form for lab-confirmed enterovirus infection reported from February 2019 to January 2020, including patients clinical characteristics, and laboratory data was distributed through 25 laboratories participating the survey. Results Overall, a homogenous laboratory capacity for enterovirus infection diagnosis was found and 21,000 diagnostic tests were retrospectively reported in 2018. Then, in 2019, two outbreaks of Echovirus 30 were identified and confirmed by molecular analyses. Conclusion These results underline the need monitor the circulation of non-polio enterovirus to ascertain the real burden of the disease in the country.

Hereby, the partial Viral Protein 1 sequences of Coxsackievirus B5 (CV-B5) from sewage samples, collected in Italy from 2016 to 2017, were compared with those available in GenBank from clinical samples. Phylogenetic analysis highlighted: (I) the predominant circulation of CV-B5 genogroup B in Italy, and (II) the presence of two new sub-genogroups.

Human enteroviruses (HEVs) occur in high concentrations in wastewater and can contaminate receiving environmental waters, constituting a major cause of acute waterborne disease worldwide. In this study, we investigated the relative abundance, occurrence, and seasonal distribution of polio and other enteroviruses at three wastewater treatment plants (WWTPs) in Naples, Southern Italy, from January 2010 to December 2014. Influent and effluent samples from the three WWTPs were collected monthly. One hundred and sixty-one of the 731 wastewater samples collected (22.0%) before and after water treatment were CPE positive on RD cells; while no samples were positive on L20B cells from any WWTPs. Among the 140 non-polio enterovirus isolated from inlet sewage, 69.3% were Coxsackieviruses type B and 30.7% were Echoviruses. Among these, CVB3 and CVB5 were most prevalent, followed by CVB4 and Echo6. The twenty-one samples tested after treatment contained 6 CVB4, 5 CVB3, 3 Echo11, and 2 Echo6; while other serotypes were isolated less frequently. Data on viral detection in treated effluents of WWTPs confirmed the potential environmental contamination by HEVs and could be useful to establish standards for policies on wastewater management.

The WHO Regional Commission for the Certification of Poliomyelitis Eradication has recently indicated Bosnia and Herzegovina (B&H) as a high risk country for transmission, following importation, of wild poliovirus (WPV) or circulating vaccine-derived poliovirus (cVDPV). We analyzed data on Acute Flaccid Paralysis (AFP) surveillance between 2007 to 2016, and the trend of polio immunization coverage in B&H. The majority of AFP cases was recorded in 2016 suggesting an enhancement of the AFP surveillance activities. However, the decline in the immunization coverage, around 74%, and the isolation of two Sabin-like poliovirus type 2 strains, one of them close to a VDPV, require a particular attention in the area. Although B&H has successfully maintained its polio-free status since 2002 several challenges need to be addressed. This article is protected by copyright. All rights reserved

This study evaluated the presence and seasonal distribution of polio and other enteroviruses in four wastewater treatment plants in three cities in Italy, using different treatment systems. Detection of enteroviruses was carried out by virus isolation in cell cultures after concentration of water samples collected at both inlet and outlet of the treatment plants, following the methods described in the WHO guidelines. Viral serotypes isolated before and after water treatment were compared. Forty-eight non-polio enteroviruses were isolated from 312 samples collected at the inlet of the four wastewater treatment plants, 35 of which were Coxsackievirus type B (72.9 %) and 13 Echovirus (27.1 %). After treatment, 2 CVB3, 1 CVB5, and 1 Echo 6 were isolated. CVB3 and Echo 6 serotypes were also detected in samples collected at the inlet of the TP, in the same month and year. The high rate of detection of infectious enteroviruses in inlet sewage samples (30.1 %) indicates wide diffusion of these viruses in the populations linked to the collectors. The incomplete removal of infectious viruses following sewage treatment highlights possible risks for public health relate to treated waters discharge into the environment.

Maintenance energy expenditure (EE) and requirements of the cat refer mainly to body weight, sexual status and activity. A recent study did not show any effect of age or season on EE when expressed...

A new rapid method for identification and determination of the titer of polioviruses and other enteroviruses in cell monolayers grown in microtiter plates is described. The method is based on immunoperoxidase staining of infected cells with commercial monoclonal antibodies (MAb) and biotin-labeled secondary antibody. The presence of poliovirus or other enteroviruses was established as the appearance of at least one focus of cells with stained cytoplasm 6 h post-infection. Viral titers determined by this method were expressed as focus forming unit (FFU) per ml which was found to correspond approximately to 10 TCID(50)/ml. The suitability of this technique to determine poliovirus antibody titers in human sera was also tested comparing the immunocytochemical neutralization assay with a conventional neutralization in microtiter plates. The test was standardized using reference human sera in order to produce antibody titers expressed in international units (IU). In addition to high reproducibility, the new neutralization test appears to be sensitive, specific and rapid, and might thus represent a useful tool for the diagnosis of polio and other enterovirus infections.

An Acute Flaccid Paralysis (AFP) surveillance system was set up in Lombardy (Northern Italy) in 1997 in the framework of the national AFP surveillance system, as part of the polio eradication initiative by the World Health Organization (WHO). This surveillance system can now be used to detect Poliovirus (PV) reintroductions from endemic countries. This study aimed at describing the results of the AFP surveillance in Lombardy, from 1997 to 2011. Overall, 131 AFP cases in Lombardy were reported with a mean annual incidence rate of 0.7/100 000 children

Sewage surveillance in seven Italian cities between 2005 and 2008, after the introduction of inactivated poliovirus vaccination (IPV) in 2002, showed rare polioviruses, none that were wild-type or circulating vaccine-derived poliovirus (cVDPV), and many other enteroviruses among 1,392 samples analyzed. Two of five polioviruses (PV) detected were Sabin-like PV2 and three PV3, based on enzyme-linked immunosorbent assay (ELISA) and PCR results. Neurovirulence-related mutations were found in the 5′ noncoding region (5′NCR) of all strains and, for a PV2, also in VP1 region 143 (Ile > Thr). Intertypic recombination in the 3D region was detected in a second PV2 (Sabin 2/Sabin 1) and a PV3 (Sabin 3/Sabin 2). The low mutation rate in VP1 for all PVs suggests limited interhuman virus passages, consistent with efficient polio immunization in Italy. Nonetheless, these findings highlight the risk of wild or Sabin poliovirus reintroduction from abroad. Non-polio enteroviruses (NPEVs) were detected, 448 of which were coxsackievirus B (CVB) and 294 of which were echoviruses (Echo). Fifty-six NPEVs failing serological typing were characterized by sequencing the VP1 region (nucleotides [nt] 2628 to 2976). A total of 448 CVB and 294 Echo strains were identified; among those strains, CVB2, CVB5, and Echo 11 predominated. Environmental CVB5 and CVB2 strains from this study showed high sequence identity with GenBank global strains. The high similarity between environmental NPEVs and clinical strains from the same areas of Italy and the same periods indicates that environmental strains reflect the viruses circulating in the population and highlights the potential risk of inefficient wastewater treatments. This study confirmed that sewage surveillance can be more sensitive than acute flaccid paralysis (AFP) surveillance in monitoring silent poliovirus circulation in the population as well as the suitability of molecular approaches to enterovirus typing.

The last case of poliomyelitis due to transmission of indigenous wild poliovirus occurred in Italy in 1982. To achieve the certification of the eradication of poliomyelitis in Italy, an active surveillance of acute flaccid paralysis (AFP) in the population aged less than 15 years was set up following the World Health Organization (WHO) guidelines. The survey started in 1996 with a pilot study involving 4 out of 21 regions, and was gradually extended to a national level in 1997. The two-year survey identified five patients with diagnosis of vaccine associated paralytic poliomyelitis (VAPP). Polioviruses type 2 and 3 Sabin-like were isolated and characterized in three of them. In the remaining two cases, samples were collected late after the onset of symptoms, and poliovirus could not be isolated. No wild polioviruses were detected during the survey. The rate of non-polio AFP found in Italy in 1997 was 0.61 cases per 100,000, which is lower than the level of 1.0 case per 100,000 considered as acceptable by the WHO. This was mainly due to the delay in organizing the hospital network and starting the active search of AFP cases in the largest and most densely populated regions. Therefore, the overall rate of AFP found in Italy underestimates the global effectiveness of the program, which however will be better evaluated in the next few years. This study is the first systematic attempt to determine the rate of AFP in Italy.

Mass vaccination has led poliomyelitis to become a rare disease in a large part of the world, including Western Europe. However, in the past 20 years wild polioviruses imported from countries where polio is endemic have been responsible for outbreaks in otherwise polio-free European countries. We report on the characterization of poliovirus isolates from a large outbreak of poliomyelitis that occurred in Albania in 1996 and that also spread to the neighboring countries of Yugoslavia and Greece. The epidemics involved 145 subjects, mostly young adults, and caused persisting paralysis in 87 individuals and 16 deaths. The agent responsible for the outbreak was isolated from 74 patients and was identified as wild type 1 poliovirus by both immunological and molecular methods. Sequence analysis of the genome demonstrated the involvement of a single virus strain throughout the epidemics, and genotyping analysis showed 95% homology of the strain with a wild type 1 poliovirus strain isolated in Pakistan in 1995. Neutralization assays with both human sera and monoclonal antibodies were performed to analyze the antigenic structure of the epidemic strain, suggesting its peculiar antigenic characteristics. The presented data underline the current risks of outbreaks due to imported wild poliovirus and emphasize the need to improve vaccination efforts and also the need to implement surveillance in countries free of indigenous wild poliovirus.

Twenty-two newly diagnosed insulin-dependent diabetics and 46 control subjects have been examined for Coxsackie B1-6 serum antibodies. Evidence for CoxB4 neutralizing antibodies at titers greater than or equal to 16 and two seroconversions for this single virus type were shown in the diabetic group (31.8% of patients with titers greater than or equal to 16 in comparison with 10% of controls, p = 0.08). Reduced titers against CoxB2 and CoxB5 in diabetics were also observed. In agreement with the majority of publications, these data suggest the hypothesis that CoxB4 infections are frequently associated with type 1 diabetes, and the positive relationship found only for this type of virus may be related to greater tropism for the pancreas. The specificity of this viral infection, as shown by our serologic results, could suggest a possible causative role in the development of type 1 diabetes only in a limited number of cases. The authors propose new studies with monoclonal and IgM specific antibodies, obtained from new isolates, to detect more accurately the qualiquantitative differences between type 1 diabetics and controls.

Fifteen cases of presumptive poliomyelitis occurring in Italy between 1981–85 were studied in order to differentiate between paralysis caused by poliovirus and that of different etiology. Out of seven confirmed cases three were ≪ temporally associated with vaccination ≫. Three aspects are discussed: i) the need for a careful differential diagnosis of paralytic cases; ii) the overconcern about the problem of vaccine-associated cases: iii) the risk connected with re-importation of wild poliovirus strains.

Background Vaccine-associated paralytic poliomyelitis (VAPP) and immunodeficient long-term polio excretors constitute a significant public health burden and are a major concern for the WHO global polio eradication endgame. Case presentation Poliovirus type 3 characterized as Sabin-like was isolated from a 5-month-old Albanian child with X-linked agammaglobulinemia and VAPP after oral polio vaccine administration. Diagnostic workup and treatment were performed in Italy. Poliovirus replicated in the gut for 7 months. The 5’ non coding region (NCR), VP1, VP3 capsid proteins and the 3D polymerase genomic regions of sequential isolates were sequenced. Increasing accumulation of nucleotide mutations in the VP1 region was detected over time, reaching 1.0 % of genome variation with respect to the Sabin reference strain, which is the threshold that defines a vaccine-derived poliovirus (VDPV). We identified mutations in the 5’NCR and VP3 regions that are associated with reversion to neurovirulence. Despite this, all isolates were characterized as Sabin-like. Several amino acid mutations were identified in the VP1 region, probably involved in growth adaptation and viral persistence in the human gut. Intertypic recombination with Sabin type 2 polio in the 3D polymerase region, possibly associated with increased virus transmissibility, was found in all isolates. Gamma-globulin replacement therapy led to viral clearance and neurological improvement, preventing the occurrence of persistent immunodeficiency-related VDPV. Conclusions This is the first case of VAPP in an immunodeficient child detected in Albania through the Acute Flaccid Paralysis surveillance system and the first investigated case of vaccine associated poliomyelitis in Italy since the introduction of an all-Salk schedule in 2002. We discuss over the biological and clinical implications in the context of the Global Polio Eradication Program and emphasize on the importance of the Acute Flaccid Paralysis surveillance.