Fathead minnow nidovirus infects spotfin shiner Cyprinella spiloptera and golden shiner Notemigonus crysoleucas.

Since the initial isolation of the fathead minnow nidovirus (FHMNV), concerns have been raised regarding the risks it may pose to other fish species. In this study, 7 fish species resident to the Laurentian Great Lakes were challenged intraperitoneally with 2 doses of FHMNV: 102.8 and 104.8 median tissue culture infective dose (TCID(50)) ml(-1). Infected spotfin shiner Cyprinella spiloptera and golden shiner Notemigonus crysoleucas suffered morbidity and mortality during the 40 d observation period, while other species, including creek chub Semotilus atromaculatus, rainbow trout Oncorhynchus mykiss, largemouth bass Micropterus salmoides and walleye Sander vitreus, showed no clinical signs or mortality. FHMNV was re-isolated on the epithelioma papulosum cyprini cell line from the tissues of infected spotfin shiner and golden shiner, which harbored high numbers of viral RNA copies as measured by quantitative loop-mediated isothermal amplification. Infected spotfin shiner and golden shiner exhibited external petechiae, exophthalmia, oedematous kidneys, and liver pallor. Histopathological analysis revealed multifocal areas of necrosis in the kidney, spleen and liver of infected fish. Spotfin shiner and golden shiner were then infected with 2 doses of FHMNV (10(3.5) and 10(3.9) TCID(50) ml(-1)) by immersion to mimic more natural modes of infection. Spotfin shiner experienced 60% mortality at both doses, while golden shiner did not experience mortality nor develop any clinical signs following a 40 d observation period. Overall, piscivorous fish tested in this study do not seem to be at risk for infection, while cyprinids appear to vary in their susceptibility to the strain of FHMNV used in this study.

Novel divergent nidovirus in a python with pneumonia.

The order Nidovirales contains large, enveloped viruses with a non-segmented positive-stranded RNA genome. Nidoviruses have been detected in man and various animal species, but, to date, there have been no reports of nidovirus in reptiles. In the present study, we describe the detection, characterization, phylogenetic analyses and disease association of a novel divergent nidovirus in the lung of an Indian python (Python molurus) with necrotizing pneumonia. Characterization of the partial genome (>33 000 nt) of this virus revealed several genetic features that are distinct from other nidoviruses, including a very large polyprotein 1a, a putative ribosomal frameshift signal that was identical to the frameshift signal of astroviruses and retroviruses and an accessory ORF that showed some similarity with the haemagglutinin-neuraminidase of paramyxoviruses. Analysis of genome organization and phylogenetic analysis of polyprotein 1ab suggests that this virus belongs to the subfamily Torovirinae. Results of this study provide novel insights into the genetic diversity within the order Nidovirales.

Vomiting and wasting disease associated with hemagglutinating encephalomyelitis viruses infection in piglets in Jilin, China.

One coronavirus strain was isolated from brain tissues of ten piglets with evident clinical manifestations of vomiting, diarrhea and dyskinesia in Jilin province in China. Antigenic and genomic characterizations of the virus (isolate PHEV-JLsp09) were based on multiplex PCR and negative staining electron microscopy and sequence analysis of the Hemagglutinin-esterase (HE) gene. These piglets were diagnosed with Porcine hemagglutinating encephalomyelitis virus (PHEV).Necropsy was performed on the piglets. Major pathological changes included meningeal hyperemia, meningeal hemorrhage and cortical hemorrhage. Minor changes were also observed in other organs. Histopathological changes included satellitosis and neuronophagia in the cerebral cortex.Mice were infected with the isolated virus. Their histopathological changes were similar to those symptoms observed in the piglets, exhibiting typical changes for non-suppurative encephalitis. Thus, Porcine hemagglutinating encephalomyelitis virus mainly causes damage to the nervous system but also impacts other organs. This viral strain (isolate PHEV-JLsp09) found in the Siping area of Jilin Province in China is evolutionally closest to the HEV-67N stain (North American strain), indicating that this viral strain evolved from the PHEV from North America.

Respiratory disease in ball pythons (Python regius) experimentally infected with ball python nidovirus.

Circumstantial evidence has linked a new group of nidoviruses with respiratory disease in pythons, lizards, and cattle. We conducted experimental infections in ball pythons (Python regius) to test the hypothesis that ball python nidovirus (BPNV) infection results in respiratory disease. Three ball pythons were inoculated orally and intratracheally with cell culture isolated BPNV and two were sham inoculated. Antemortem choanal, oroesophageal, and cloacal swabs and postmortem tissues of infected snakes were positive for viral RNA, protein, and infectious virus by qRT-PCR, immunohistochemistry, western blot and virus isolation. Clinical signs included oral mucosal reddening, abundant mucus secretions, open-mouthed breathing, and anorexia. Histologic lesions included chronic-active mucinous rhinitis, stomatitis, tracheitis, esophagitis and proliferative interstitial pneumonia. Control snakes remained negative and free of clinical signs throughout the experiment. Our findings establish a causal relationship between nidovirus infection and respiratory disease in ball pythons and shed light on disease progression and transmission.

The aetiology of wobbly possum disease: Reproduction of the disease with purified nidovirus.

The objective of this study was to investigate a role of a recently discovered marsupial nidovirus in the development of a neurological disease, termed wobbly possum disease (WPD), in the Australian brushtail possum (Trichosurus vulpecula). Four possums received 1 mL of a standard inoculum that had been prepared from tissues of WPD-affected possums, 4 possums received 1.8 mL (1 × 10(6) TCID50) of a cell lysate from inoculated cultures, and 4 possums received 1 mL (× 10(7) TCID50) of a purified WPD isolate. All but one possum that received infectious inocula developed neurological disease and histopathological lesions characteristic for WPD. High levels of viral RNA were detected in livers from all possums that received infectious inocula, but not from control possums. Altogether, our data provide strong experimental evidence for the causative involvement of WPD virus in development of a neurological disease in infected animals.