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Iridoviridae are known to cause disease in sturgeons in North America. Here, histological and molecular methods were used to screen for this family of virus in sturgeons from various European farms with low-to-high morbidity. Some histological samples revealed basophilic cells in the gill and labial epithelia, strongly suggesting the accumulation of iridovirus particles. Newly developed generic PCR tests targeting the major capsid protein (MCP) gene of sturgeon iridoviruses identified in North America, namely the white sturgeon iridovirus and the Namao virus (NV), produced positive signals in most samples from four sturgeon species: Russian (Acipenser gueldenstaedtii), Siberian (A. baerii), Adriatic (A. naccarii) and beluga (Huso huso). The sequences of the PCR products were generally highly similar one another, with nucleotide identities greater than 98%. They were also related to (74-88%), although distinct from, American sturgeon iridoviruses. These European viruses were thus considered variants of a single new virus, provisionally named Acipenser iridovirus-European (AcIV-E). Moreover, three samples infected with AcIV-E showed genetic heterogeneity, with the co-existence of two sequences differing by five nucleotides. One of our European samples carried a virus distinct from AcIV-E, but closely related to NV identified in Canada (95%). This study demonstrates the presence of two distinct sturgeon iridoviruses in Europe: a new genotype AcIV-E and an NV-related virus.

A survey of anelloviruses in swine herds from Britanny, France, is reported. By using PCR targeted to the conserved untranslated region, prevalences of 93 and 73 % were found among 15 herds and 33 animals, respectively. The lung was the organ found to be positive most frequently among the five organs tested from 32 animals. The highest identity levels of our nucleotide sequences were found with pig isolates from Japan and with an isolate from Tupaia belangeri. Interestingly, when aligning all available swine isolates from France and Japan, at least two phylogenetic groups were identified, each one containing clones from France and Japan. Some animals carried clones from both groups, demonstrating intra-individual variability. Despite the putative harmlessness of anelloviruses, the potential inoculum carried by pigs must be further evaluated as a sanitary threat.Anellovirus is a recently created, floating genus of small, non-enveloped viruses that infect a wide range of mammalian species (Biagini et al., 2004). Their genome is composed of circular, negative-sense, single-stranded DNA that carries an untranslated region (UTR) and at least two majors ORFs. The type species, Torque teno virus (TTV), was discovered in a human patient affected by hepatitis of unknown origin (Nishizawa et al., 1997). In a short time, the suspected relationship between TTV and hepatitis, or any other pathology, was rejected after multiple reports of very high viral prevalences in diverse human populations, ranging around 80 % (reviewed by Bendinelli et al., 2001). Moreover, TTV infects not only the liver, but also many other organs, of a single individual without apparent pathology. Between isolates, the virus exhibited high genomic diversity: at the time of writing, human TTV variants are classified into five major phylogenetic groups (Peng et al., 2002). Noticeably, human individuals may carry several distinct genotypes (Ball et al., 1999; Biagini et al., 1999;Jelcic et al., 2004;Kakkola et al., 2004;Verschoor et al., 1999).Other anelloviruses have been partially or fully characterized in several animal species, including domestic animals, such as dogs, cats, pigs, bovines, chickens and ovines, as well as wild animals, such as tupaias (tree shrews) and non-human primates (Cong et al., 2000;Leary et al., 1999;Okamoto et al., 2001bOkamoto et al., , 2002Verschoor et al., 1999). Interestingly, the genome of anelloviruses tends to be smaller when the order of the infected animal is lower, varying from 3?8 kb for human viruses to 2?2 kb for tupaia viruses and reaching 2?9 kb for the only available fulllength viral genome from a pig (Sus domesticus) in Japan (tentatively named TTV-Sd31) . Although less exhaustive than for humans, studies suggest high natural prevalences of anelloviruses in some animals, as well as some intra-and inter-individual genetic variability (Okamoto et al., 2001b;Thom et al., 2003;Verschoor et al., 1999). Recently, viral prevalences ranging between 33 and 100 % have been reported in the sera of pigs from Canada, Chi...

A betanodavirus associated with a massive mortality was isolated from larvae of tilapia, Oreochromis niloticus, maintained in fresh water at 30 degrees C. Histopathology revealed vacuolation of the nervous system, suggesting an infection by a betanodavirus. The virus was identified by indirect fluorescent antibody test in the SSN1 cell line and further characterized by sequencing of a PCR product. Sequencing of the T4 region of the coat protein gene indicated a phylogenetic clustering of this isolate within the red-spotted grouper nervous necrosis virus type. However, the tilapia isolate formed a unique branch distinct from other betanodavirus isolates. The disease was experimentally reproduced by bath infection of young tilapia at 30 degrees C. The reservoir of virus at the origin of the outbreak remains unidentified. To our knowledge, this is the first report of natural nodavirus infection in tilapia reared in fresh water.