Isolation and genetic characterization of canine adenovirus type 2 from a domestic dog showing neurological symptoms.

Canine adenoviruses (CAVs) are of two types: canine adenovirus type 1 (CAV-1), which causes infectious canine hepatitis, and canine adenovirus type 2 (CAV-2), which is mainly associated with the respiratory type of disease in dogs. Due to the widespread use of modified live vaccines to control canine adenoviral infections and subsequently reduced disease incidence, CAVs are often neglected by clinicians. Although a number of studies are available about CAV-1 prevalence in India, only meagre information is available about CAV-2. This study reports the CAV-2 infection in a vaccinated dog with neurological and respiratory symptoms which was found negative for other canine pathogens like canine distemper virus and canine parvovirus. The virus was successfully isolated from rectal swab in MDCK cells and characterized by immunofluorescence assay and virus neutralization test. On phylogenetic analysis of partial E3 region, the Indian CAV-2 grouped in a separate clade different from established subgroups. An insertion of "G" nucleotide was reported at nucleotide (nt.) position 1077 in the E3 gene of Indian CAV-2 isolates which led to a frameshift in the coding region of E3 gene thereby imparting additional eleven amino acids to its C-terminal end in comparison to isolates from other parts of the world. This may have an implication on the functional role of E3 protein inside the cell. This study reinforces the unique signature insertion in the E3 gene of Indian CAV-2 and is the second study in the world to report the association of CAV-2 with neurological disease in dogs.

Theory of creeping gravity currents of a non-Newtonian liquid.

Recently several experiments on creeping gravity currents have been performed, using highly viscous silicone oils and putties. The interpretation of the experiments relies on the available theoretical results that were obtained by means of the lubrication approximation with the assumption of a Newtonian rheology. Since very viscous fluids are usually non-Newtonian, an extension of the theory to include non-Newtonian effects is needed. We derive the governing equations for unidirectional and axisymmetric creeping gravity currents of a non-Newtonian liquid with a power-law rheology, generalizing the usual lubrication approximation. The equations differ from those for Newtonian liquids, being nonlinear in the spatial derivative of the thickness of the current. Similarity solutions for currents whose volume varies as a power of time are obtained. For the spread of a constant volume of liquid, analytic solutions are found that are in good agreement with experiment. We also derive solutions of the waiting-time type, as well as those describing steady flows from a constant source to a sink. General traveling-wave solutions are given, and analytic formulas for a simple case are derived. A phase plane formalism that allows the systematic derivation of self-similar solutions is introduced. The application of the Boltzmann transform is briefly discussed. All the self-similar solutions obtained here have their counterparts in Newtonian flows, as should be expected because the power-law rheology involves a single-dimensional parameter as the Newtonian constitutive relation. Thus one finds similarity solutions whenever the analogous Newtonian problem is self-similar, but now the spreading relations are rheology-dependent. In most cases this dependence is weak but leads to significant differences easily detected in experiments. The present results may also be of interest for geophysics since the lithosphere deforms according to an average power-law rheology.