Correction to: Recommendations for the nomenclature of enteroviruses and rhinoviruses.

Unfortunately, one of the affiliations of author "A. E. Gorbalenya" was missed in original version. The affiliation is updated here.

Recommendations for the nomenclature of enteroviruses and rhinoviruses.

Enteroviruses (EVs) and rhinoviruses (RVs) are significant pathogens of humans and are the subject of intensive clinical and epidemiological research and public health measures, notably in the eradication of poliovirus and in the investigation and control of emerging pathogenic EV types worldwide. EVs and RVs are highly diverse in their antigenic properties, tissue tropism, disease associations and evolutionary relationships, but the latter often conflict with previously developed biologically defined terms, such as "coxsackieviruses", "polioviruses" and "echoviruses", which were used before their genetic interrelationships were understood. This has created widespread formatting problems and inconsistencies in the nomenclature for EV and RV types and species in the literature and public databases. As members of the International Committee for Taxonomy of Viruses (ICTV) Picornaviridae Study Group, we describe the correct use of taxon names for these viruses and have produced a series of recommendations for the nomenclature of EV and RV types and their abbreviations. We believe their adoption will promote greater clarity and consistency in the terminology used in the scientific and medical literature. The recommendations will additionally provide a useful reference guide for journals, other publications and public databases seeking to use standardised terms for the growing multitude of enteroviruses and rhinoviruses described worldwide.

The evolution and phylodynamics of serotype A and SAT2 foot-and-mouth disease viruses in endemic regions of Africa.

Foot-and-mouth disease (FMD) is a major livestock disease with direct clinical impacts as well as indirect trade implications. Control through vaccination and stamping-out has successfully reduced or eradicated the disease from Europe and large parts of South America. However, sub-Saharan Africa remains endemically affected with 5/7 serotypes currently known to be circulating across the continent. This has significant implications both locally for livestock production and poverty reduction but also globally as it represents a major reservoir of viruses, which could spark new epidemics in disease free countries or vaccination zones. This paper describes the phylodynamics of serotypes A and SAT2 in Africa including recent isolates from Cameroon in Central Africa. We estimated the most recent common ancestor for serotype A was an East African virus from the 1930s (median 1937; HPD 1922-1950) compared to SAT2 which has a much older common ancestor from the early 1700s (median 1709; HPD 1502-1814). Detailed analysis of the different clades shows clearly that different clades are evolving and diffusing across the landscape at different rates with both serotypes having a particularly recent clade that is evolving and spreading more rapidly than other clades within their serotype. However, the lack of detailed sequence data available for Africa seriously limits our understanding of FMD epidemiology across the continent. A comprehensive view of the evolutionary history and dynamics of FMD viruses is essential to understand many basic epidemiological aspects of FMD in Africa such as the scale of persistence and the role of wildlife and thus the opportunities and scale at which vaccination and other controls could be applied. Finally we ask endemic countries to join the OIE/FAO supported regional networks and take advantage of new cheap technologies being rolled out to collect isolates and submit them to the World Reference Laboratory.

Transboundary movements of foot-and-mouth disease from India to Sri Lanka: A common pattern is shared by serotypes O and C.

Foot-and-mouth disease (FMD) affects the livestock industry in a transboundary manner. It is essential to understand the FMD phylodynamics to assist in the disease-eradication. FMD critically affects the Sri Lankan cattle industry causing substantial economic losses. Even though many studies have covered the serotyping and genotyping of FMD virus (FMDV) in Sri Lanka, there is a significant knowledge gap exists in understanding the FMDV phylodynamics in the country. In the present study, the VP1 genomic region of FMD viral isolates belonging to serotype C from Sri Lanka and other South Asian countries were sequenced. All the published VPI sequences of serotype C and most of the published VP1 sequences for lineage ME-SA/Ind-2001d of serotype O from Sri Lanka, India, and other South Asian countries were retrieved. The datasets of serotype C and serotype O were separately analyzed using Bayesian, maximum likelihood, and phylogenetic networking methods to infer the transboundary movements and evolutionary aspects of the FMDV incursions in Sri Lanka. A model-based approach was used to detect any possible recombination events of FMDV incursions. Our results revealed that the invasions of the topotype ASIA of serotype C and the lineage ME-SA/Ind-2001d have a similar pattern of transboundary movement and evolution. The haplotype networks and phylogenies developed in the present study confirmed that FMDV incursions in Sri Lanka mainly originate from the Indian subcontinent, remain quiet after migration, and then cause outbreaks in a subsequent year. Since there are no recombination events detected among the different viral strains across serotypes and topotypes, we can assume that the incursions tend to show the independent evolution compared to the ancestral viral populations. Thus, we highlight the need for thorough surveillance of cattle/ruminants and associated product-movement into Sri Lanka from other regions to prevent the transboundary movement of FMDV.

Correction: The phylogenetic analysis of VP1 genomic region in foot-and-mouth disease virus serotype O isolates in Sri Lanka reveals the existence of 'Srl-97', a newly named endemic lineage.

[This corrects the article DOI: 10.1371/journal.pone.0194077.].

The phylogenetic analysis of VP1 genomic region in foot-and-mouth disease virus serotype O isolates in Sri Lanka reveals the existence of 'Srl-97', a newly named endemic lineage.

Foot and mouth disease (FMD) has devastated the cattle industry in Sri Lanka many times in the past. Despite its seriousness, limited attempts have been made to understand the disease to ameliorate its effects-current recommendation for vaccines being based solely on immunological assessments rather than on molecular identification. The general belief is that the cattle population in Sri Lanka acquired the FMD virus (FMDV) strains via introductions from India. However, there could be endemic FMDV lineages circulating in Sri Lanka. To infer the phylogenetic relationships of the FMDV strains in the island, we sequenced the VP1 genomic region of the virus isolates collected during the 2014 outbreak together with a few reported cases in 2012 and 1997 and compared them to VP1 sequences from South Asia. The FMDV strains collected in the 2014 outbreak belonged to the lineage, Ind-2001d, of the topotype, ME-SA. The strains collected in 2012 and 1997 belonged to another lineage called 'unnamed' by the World Reference Laboratory for Foot and Mouth Disease (WRLFMD). Based on the present analysis, we designate the lineage 'unnamed' as Srl-97 which we found endemic to Sri Lanka. The evolutionary rates of Srl-97 and Ind-2001d in Sri Lanka were estimated to be 0.0004 and 0.0046 substitutions/site/year, respectively, suggesting that Srl-97 evolves slowly.

Outbreak investigations and molecular characterization of foot-and-mouth disease viruses circulating in south-west Niger.

In Niger, the epidemiological situation regarding foot-and-mouth disease is unclear as many outbreaks are unreported. This study aimed (i) to identify Foot-and-mouth disease virus (FMDV) strains currently circulating in cattle herds, and (ii) to identify risk factors associated with Foot-and-mouth disease (FMD)-seropositive animals in clinical outbreaks. Epithelial tissues (n = 25) and sera (n = 227) were collected from cattle in eight districts of the south-western part of Niger. Testing of clinical material revealed the presence of FMDV serotype O that was characterized within the O/WEST AFRICA topotype. The antigenic relationship between one of the FMDV isolates from Niger (O/NGR/4/2015) and three reference vaccine strains was determined by the two-dimensional virus neutralization test (2dmVNT), revealing a close antigenic match between the field isolate from Niger and three FMDV serotype O vaccine strains. Serological analyses using a non-structural protein (NSP) test provided evidence for previous FMDV infection in 70% (158/227) of the sera tested. Multivariate logistic regression analysis revealed that only the herd composition (presence of both cattle and small ruminants) was significantly associated with FMDV seropositivity as defined by NSP-positive results (p-value = .006). Of these positive sera, subsequent testing by liquid-phase blocking ELISA (LPBE) showed that 86% (136/158) were positive for one (or more) of four FMDV serotypes (A, O, Southern African Territories (SAT) 1 and SAT 2). This study provides epidemiological information about FMD in the south-western part of Niger and highlights the complex transboundary nature of FMD in Africa. These findings may help to develop effective control and preventive strategies for FMD in Niger as well, as other countries in West Africa.

Emergence of an exotic strain of serotype O foot-and-mouth disease virus O/ME-SA/Ind-2001d in South-East Asia in 2015.

The O/Middle East-South Asia (ME-SA)/Ind-2001 lineage of foot-and-mouth disease virus (FMDV) is endemic in the Indian subcontinent and has been reported in the Middle East and North Africa, but it had not been detected in South-East Asia (SEA) before 2015. This study reports the recent incursions of this viral lineage into SEA, which caused outbreaks in Vientiane Capital of Lao People's Democratic Republic (PDR) in April 2015, in Dak Nong, Dak Lak and Ninh Thuan Provinces of Vietnam from May to October 2015, and in Rakhine State of Myanmar in October 2015. Disease investigations were conducted during the outbreaks and followed up after laboratory results confirmed the involvement of FMDV O/ME-SA/Ind-2001 sublineage d (O/ME-SA/Ind-2001d). Affected host species included cattle, buffalo and pig, and all the outbreaks resolved within 2 months. Animals with clinical signs were separated, and affected premises were disinfected. However, strict movement restrictions were not enforced, and emergency vaccinations were only implemented in Vientiane Capital of Lao PDR and Dak Nong and Ninh Thuan Provinces of Vietnam. Clinical samples were collected from each outbreak and examined by nucleotide sequencing of the FMDV viral protein 1 coding region. Sequence analysis revealed that the O/ME-SA/Ind-2001d isolates from Lao PDR and Vietnam were closely related to each other and similar to viruses previously circulating in India in 2013. Viruses collected from Myanmar were divergent from viruses of the same sublineage recovered from Lao PDR and Vietnam but were closely related to viruses present in Bangladesh in 2015. These findings imply that at least two independent introductions of O/ME-SA/Ind-2001d into SEA have occurred. Our study highlights the transboundary nature of foot-and-mouth disease (FMD) and reinforces the importance of improved FMD surveillance and promotion of safer cross-border trade in SEA to control the risk of introduction and spread of exotic FMDV strains.

ICTV Virus Taxonomy Profile: Picornaviridae.

The family Picornaviridae comprises small non-enveloped viruses with RNA genomes of 6.7 to 10.1 kb, and contains >30 genera and >75 species. Most of the known picornaviruses infect mammals and birds, but some have also been detected in reptiles, amphibians and fish. Many picornaviruses are important human and veterinary pathogens and may cause diseases of the central nervous system, heart, liver, skin, gastrointestinal tract or upper respiratory tract. Most picornaviruses are transmitted by the faecal-oral or respiratory routes. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Picornaviridae, which is available at www.ictv.global/report/picornaviridae.

Characterization of Foot-and-Mouth Disease Viruses Collected in Nigeria Between 2007 and 2014: Evidence for Epidemiological Links Between West and East Africa.

This study describes the molecular characterization of 47 foot-and-mouth disease (FMD) viruses recovered from field outbreaks in Nigeria between 2007 and 2014. Antigen ELISA of viral isolates was used to identify FMD virus serotypes O, A and SAT 2. Phylogenetic analyses of VP1 nucleotide sequences provide evidence for the presence of multiple sublineages of serotype SAT 2, and O/EAST AFRICA 3 (EA-3) and O/WEST AFRICA topotypes in the country. In contrast, for serotype A, a single monophyletic cluster of viruses has persisted within Nigeria (2009-2013). These results demonstrate the close genetic relatedness of viruses in Nigeria to those from other African countries, including the first formal characterization of serotype O/EA-3 viruses in Nigeria. The introductions and persistence of certain viral lineages in Nigeria may reflect transmission patterns via nomadic pastoralism and animal trade. Continuous monitoring of field outbreaks is necessary to dissect the complexity of FMD epidemiology in sub-Saharan Africa.

Genomics and outbreaks: foot and mouth disease.

Foot and mouth disease virus (FMDV) is an animal pathogen of global economic significance. Identifying the sources of outbreaks plays an important role in disease control; however, this can be confounded by the ease with which FMDV can spread via movement of infected livestock and animal products, aerosols or fomites, e.g. contaminated persons and objects. As sequencing technologies have advanced, this review highlights the uses of viral genomic data in helping to understand the global distribution and transboundary movements of FMDV, and the role that these approaches have played in control and surveillance programmes. The recent application of next-generation sequencing platforms to address important epidemiological and evolutionary challenges is discussed with particular reference to the advent of 'omics' technologies.

Le virus de la fièvre aphteuse est un agent pathogène affectant les animaux d'élevage, avec des conséquences économiques considérables à l'échelle mondiale. La détection des sources des foyers est un aspect important de la lutte contre cette maladie ; l'efficacité de cette stratégie est toutefois compromise par la facilité avec laquelle le virus de la fièvre aphteuse se propage à la faveur des mouvements d'animaux ou de produits d'origine animale infectés, d'aérosols ou de personnes ou matières contaminées. Les auteurs décrivent, au fur et à mesure des avancées des technologies du séquençage, les données de la génomique virale qui ont permis de mieux comprendre la distribution mondiale et la propagation transfrontalière du virus de la fièvre aphteuse et le rôle que ces approches ont commencé à jouer dans les programmes de contrôle et de surveillance. Les auteurs examinent également les applications récentes des plates-formes de séquençage de nouvelle génération pour résoudre des problèmes épidémiologiques et évolutifs importants, en se référant particulièrement à l'avènement des technologies dites «­omiques ¼.

El virus de la fiebre aftosa es un patógeno animal que reviste importancia planetaria. A la hora de combatir la enfermedad es útil poder determinar el origen de los brotes, tarea que sin embargo puede verse frustrada por la facilidad con que el virus es capaz de diseminarse siguiendo los desplazamientos de animales o derivados animales infectados o por aerosoles o fómites (por ejemplo personas u objetos contaminados). Los autores hacen hincapié en la utilización de datos de genómica vírica para ayudar a aprehender la distribución mundial y los movimientos transfronterizos del virus de la fiebre aftosa, lo cual es posible gracias a los avances que han conocido las técnicas de secuenciación, así como en la función que pueden cumplir estos métodos dentro de los programas de control y vigilancia. También examinan la reciente aplicación de dispositivos de secuenciación de próxima generación para abordar importantes problemas epidemiológicos y evolutivos, refiriéndose especialmente al advenimiento de las técnicas «ómicas¼.

Genome Sequence of Foot-and-Mouth Disease Virus Serotype O Isolated from Morocco in 2015.

The genome of a virus isolated from an outbreak of foot-and-mouth disease (FMD) in Morocco in 2015 is described here. This virus is classified as lineage Ind-2001d within serotype O, topotype ME-SA (Middle East-South Asia). This lineage is endemic on the Indian subcontinent but has caused outbreaks in the Middle East and North Africa since 2013.

Complete Genome Sequence of a Serotype A Foot-and-Mouth Disease Virus from an Outbreak in Saudi Arabia during 2015.

The complete genome of a foot-and-mouth disease (FMD) type A virus isolated from cattle in Saudi Arabia in 2015 is described here. This virus belongs to an FMD virus lineage named genotype VII, which is normally endemic on the Indian subcontinent.

Outbreaks of Foot-and-Mouth Disease in Libya and Saudi Arabia During 2013 Due to an Exotic O/ME-SA/Ind-2001 Lineage Virus.

Foot-and-mouth disease viruses are often restricted to specific geographical regions and spread to new areas may lead to significant epidemics. Phylogenetic analysis of sequences of the VP1 genome region of recent outbreak viruses from Libya and Saudi Arabia has revealed a lineage, O-Ind-2001, normally found in the Indian subcontinent. This paper describes the characterization of field viruses collected from these cases and provides information about a new real-time RT-PCR assay that can be used to detect viruses from this lineage and discriminate them from other endemic FMD viruses that are co-circulating in North Africa and western Eurasia.

Adverse Reactions to Field Vaccination Against Lumpy Skin Disease in Jordan.

Lumpy skin disease (LSD) is an emerging disease in the Middle East region and has been recently reported in Jordan. The aim of this study was to investigate the adverse reactions that were reported after vaccine administration. Geographical areas enrolled in the study were free of the disease and away from the outbreak governorate. Sixty-three dairy cattle farms, with a total of 19,539 animals, were included in the study. Of those, 56 farms reported adverse clinical signs after vaccine administration. The duration between vaccine administration and appearance of adverse clinical signs ranged from 1 to 20 days (Mean = 10.3, SD ± 3.9). Clinical signs were similar to those observed with natural cases of lumpy skin disease. These were mainly fever, decreased feed intake, decreased milk production and variable sized cutaneous nodules (a few millimetres to around 2 cm in diameter) that could be seen anywhere on the body (head, neck, trunk, perineum), udder, and/or teats. Nodules were raised and firm initially and then formed dry scabs that could be peeled off the skin. The characteristic deep 'sit fast' appearance was rarely seen and most lesions were superficial. Some cattle had swollen lymph nodes, while a few pregnant animals aborted. The percentage of affected cattle ranged from 0.3 to 25% (Mean = 8, SD ± 5.1). Fever, decreased feed intake, and decreased milk production were seen in 83.9, 85.7, and 94.6% in cattle on the affected farms, respectively. All affected cattle displayed skin nodules over their entire bodies, while 33.9 and 7.1% of the affected farms reported nodular lesions present on the udders and teats, respectively. No mortalities were reported due to vaccine adverse reactions. Duration (course) of clinical signs ranged from 3 to 20 days (Mean = 13.7, SD ± 4.1). Two types of LSD vaccines were used by the farmers in this study. The first one was a sheep pox virus (SPPV) vaccine derived from the RM65 isolate [Jovivac, manufactured by Jordan Bioindustries Centre (JOVAC)] and the other an unlabelled one, which was later identified using PCR as a strain of lumpy skin disease virus (LSDV). Blood and skin samples collected from cattle vaccinated with the LSDV vaccine were positive for LSDV using both general and species-specific PCR primers, whereas those from cattle vaccinated with the Jovivac vaccine were negative. Adverse reactions observed in cattle after administration of the LSDV vaccine were reported to be more severe than those seen after Jovivac vaccine administration and were comparable with clinical signs observed in natural infections.

VP1 sequencing protocol for foot and mouth disease virus molecular epidemiology.

Nucleotide sequences of field strains of foot and mouth disease virus (FMDV) contribute to our understanding of the distribution and evolution of viral lineages that circulate in different regions of the world. This paper outlines a practical reversetranscription polymerase chain reaction (RT-PCR) and sequencing strategy that can be used to generate RNA sequences encoding the VP1 (1D) region of FMDV. The protocol contains a panel of PCR and sequencing primers that can be selected to characterise genetically diverse isolates representing all seven FMDV serotypes. A list of sequences is also described, comprising prototype sequences for all proposed FMDV topotypes, in order to provide a framework for phylogenetic analysis. The technical details and prototype sequences provided in this paper can be employed by FMD Reference Laboratories and others in an approach to harmonise the molecular epidemiology of FMDV.

Les séquences de nucléotides des souches de terrain du virus de la fièvre aphteuse nous aident à comprendre la distribution et l'évolution des lignées virales présentes dans les différentes régions du monde. Les auteurs décrivent les grandes lignes d'un protocole pratique, basé sur l'amplification en chaîne par polymérase couplée à une transcription inverse (RT-PCR) et sur le séquençage, qui peut être utilisé pour générer des séquences d'ARN codant pour la région VP1 (1D) du virus de la fièvre aphteuse. Le protocole permet de procéder à une sélection parmi un panel de PCR et de marqueurs de séquençage dans le but de caractériser les gènes de divers isolats représentant les sept sérotypes du virus de la fièvre aphteuse. Les auteurs décrivent également une liste de séquences pouvant servir de cadre à l'analyse phylogénétique, dont des séquences prototypes pour tous les topotypes proposés du virus de la fièvre aphteuse. Les données techniques détaillées et les séquences prototypes fournies par les auteurs peuvent être utilisées par les Laboratoires de référence pour la fièvre aphteuse et d'autres institutions, en vue d'harmoniser l'épidémiologie moléculaire du virus de la fièvre aphteuse.

Las secuencias nucleotídicas de las cepas salvajes del virus de la fiebre aftosa nos ayudan a entender la distribución y evolución de los linajes víricos circulantes en distintas regiones del mundo. Los autores exponen sucintamente un práctico procedimiento de reacción en cadena de la polimerasa acoplada a transcripción inversa (RT-PCR) y de secuenciación que se puede utilizar para generar secuencias de ARN que codifican la región VP1 (1D) del virus de la fiebre aftosa. El protocolo ofrece la posibilidad de elegir entre todo un repertorio de cebadores de PCR y de secuenciación en el que están representados los siete serotipos víricos existentes con objeto de caracterizar genéticamente diversas cepas aisladas sobre el terreno. Los autores también presentan una lista de secuencias que comprende secuencias prototípicas de todos los topotipos propuestos del virus, a fin de proporcionar un marco de referencia para el análisis filogenético. Los laboratorios de referencia para la fiebre aftosa, así como otros establecimientos, pueden servirse de las detalladas técnicas y las secuencias prototípicas aquí presentadas para armonizar el estudio de la epidemiología molecular del virus de la fiebre aftosa.

Ratification vote on taxonomic proposals to the International Committee on Taxonomy of Viruses (2015).

Changes to virus taxonomy approved and ratified by the International Committee on Taxonomy of Viruses in February 2015 are listed.

Analysis of Recent Serotype O Foot-and-Mouth Disease Viruses from Livestock in Kenya: Evidence of Four Independently Evolving Lineages.

Foot-and-mouth disease (FMD) is endemic in Kenya where four serotypes (O, A, SAT 1 and SAT 2) of the virus are currently in circulation. Within 2010 and 2011, the National Laboratory recorded an increase in the number of FMD outbreaks caused by serotype O virus. The characteristics of these viruses were determined to ascertain whether these were independent outbreaks or one single strain spreading throughout the country. The sequences of the complete VP1-coding region were analysed from viruses sampled within different areas of Kenya during 2010 and 2011. The results indicated that the 2010 to 2011 outbreaks in Kenya were caused by four independent strains. By comparison with earlier type O isolates from Eastern Africa, it was apparent that the outbreaks were caused by viruses from three different lineages of topotype EA-2 and a fourth virus strain belonging to topotype EA-4. The topotypes EA-1 and EA-3 were not detected from these outbreaks. Implications of these results for FMD control in Eastern Africa are discussed.

Molecular Characterization of Foot-and-Mouth Disease Viruses Collected in Tanzania Between 1967 and 2009.

This paper describes the molecular characterization of foot-and-mouth disease viruses (FMDV) recovered from outbreaks in Tanzania that occurred between 1967 and 2009. A total of 44 FMDV isolates, containing representatives of serotypes O, A, SAT 1 and SAT 2 from 13 regions of Tanzania, were selected from the FAO World Reference Laboratory for FMD (WRLFMD) virus collection. VP1 nucleotide sequences were determined for RT-PCR amplicons, and phylogenetic reconstructions were determined by maximum likelihood and neighbour-joining methods. These analyses showed that Tanzanian type O viruses fell into the EAST AFRICA 2 (EA-2) topotype, type A viruses fell into the AFRICA topotype (genotype I), type SAT 1 viruses into topotype I and type SAT 2 viruses into topotype IV. Taken together, these findings reveal that serotypes O, A, SAT 1 and SAT 2 that caused FMD outbreaks in Tanzania were genetically related to lineages and topotypes occurring in the East African region. The close genetic relationship of viruses in Tanzania to those from other countries suggests that animal movements can contribute to virus dispersal in sub-Saharan Africa. This is the first molecular description of viruses circulating in Tanzania and highlights the need for further sampling of representative viruses from the region so as to elucidate the complex epidemiology of FMD in Tanzania and sub-Saharan Africa.

Soft plastron, soft carapace with skeletal abnormality in juvenile tortoises. Histopathology and isolation of a novel picornavirus from Testudo graeca and Geochelone elegans.

OBJECTIVE: A disease is described in juvenile tortoises (Testudo graeca and Geochelone elegans) consisting mainly of a soft carapace, soft plastron and deformed skeleton. The aim of this study was to determine histopathological lesions and the biological properties of the isolated viruses. MATERIALS AND METHODS: Clinical signs and gross pathology were determined on diseased and healthy appearing tortoises. Paraffin sections were stained with HE, PAS and Prussian Blue and histologically examined. Terrapene heart (TH-1) cell cultures served for virus isolations from 64 tissues and 104 swabs. One isolate (isolate 1243/37 tongue) was used in neutralization tests on 19 sera. RESULTS: Retarded growth and increasingly soft plastron and carapace were the prominent signs in diseased tortoises. Pathological lesions consisted of dilated urinary sac, enlarged kidneys and livers. Histopathologically, hepatic hemosiderosis, hypoplastic anaemia, congestive glomerulonephrosis and osteodystrophy were seen. A novel vi- rus ("virus X") was isolated from 64 organs and 79 of 104 swabs. The isolated viruses were identified as a novel chelonid picornavirus based on cytopathic effect, resistance to chloroform and stability at low pH. Co-cultivation with 5-iodo-2'-deoxyuridine and actinomycin D did not reduce virus titres. Electron microscopically, round, non-enveloped particles (25-30 nm) were detected. Neutralizing antibodies to the isolate 1243/37tongue were present in 17 of 19 sera from seven species of tortoises. CONCLUSION AND CLINICAL RELEVANCE: Nephropathy, osteodystrophy and virus isolations suggest a viral aetiology. Metabolic bone disease is the major differential diagnosis. Further investigations in vivo are needed to evaluate the likely effects of the picornavirus on tortoises.