Abstract
Swine influenza virus causes respiratory disease with a major economic impact on the swine industry. The virus is also of considerable public heath concern, given the potential contribution of pigs to the development of human influenza pandemics. Isolation and identification of influenza virus in cell culture is laborious and time-consuming. Investigators in Wisconsin have developed a rapid and sensitive real-time reverse transcriptase PCR (RT-PCR) assay to facilitate screening large numbers of nasal swabs for the presence of swine influenza virus. Primers and probe were selected from a region of the virus matrix gene that is highly conserved in swine, avian, and human influenza viruses. Ninety pools of 10 nasal swab specimens each were tested using this assay. Influenza virus was detected in 8 pools, each containing 1–2 virus-positive samples; there was only 1 false-negative pool. Based on these findings, the RT-PCR assay was judged to be 100% specific and 88–100% sensitive.
Landolt GA, Karasin AI, Hofer C, Mahaney J, Svaren J, Olsen CW, Use of real-time reverse transcriptase polymerase chain reaction assay and cell culture methods for detection of swine influenza A viruses. Am J Vet Res 66:119–124, 2005
Feline mammary carcinoma (FMC) shows similarities to human breast cancer in age incidence, histopathology, and pattern of metastasis. Most FMCs are hormone receptor-negative, suggesting that they may be a suitable model for poor prognosis human breast cancer. To investigate molecular similarities between feline and human mammary tumors, international investigators analyzed the feline orthologue of the human HER2 gene, which encodes a receptor tyrosine kinase oncogene. HER2 gene expression is an important prognostic marker in human breast cancer and the HER2 protein is a target of effective monoclonal antibody therapy in some of these tumors. The kinase domain of the feline HER2 is 92% similar to the human HER2 kinase. Feline HER2 mRNA expression was increased 3–18-fold in 3 of 3 FMC cell lines, in 1 of 4 mammary adenomas, and in 6 of 11 FMC samples. An anti-human HER2 antibody recognized a protein of the appropriate size in FMC extracts and strongly stained 13 of 36 FMC samples. Thus, FMC is likely to be a suitable model for testing innovative therapies for poor prognosis human breast tumors that overexpress HER2.
De Maria R, Olivero M, Iussich S, Nakaichi M, Murata T, Biolatti B, Di Renzo MF, Spontaneous feline mammary carcinoma is a model of HER2 overexpressing poor prognosis human breast cancer. Cancer Res 65:907–912, 2005
Approximately 1% of humans and 5% of dogs have epilepsy. Lafora disease is the most severe form of teenage-onset human epilepsy. By genetic analysis of dachshunds with an autosomal recessive progressive myoclonic epilepsy similar to Lafora disease, investigators have identified a canine epilepsy disease locus (Epm2b; Nhlrc1). The Epm2b gene of normal canids has a dodecamer repeat sequence not identified in other carnivores. This sequence is unstable; when it expands, a fatal, heritable epilepsy results. A genetic test has been developed that will allow carrier and presymptomatic diagnosis and disease eradication.
Lohi H, Young EJ, Fitzmaurice SN, Rusbridge C, Chan EM, Vervoort M, Turnbull J, Zhao XC, Ianzano L, Paterson AD, Sutter NB, Ostrander EA, Andre C, Shelton GD, Ackerley CA, Scherer SW, Minassian BA, Expanded repeat in canine epilepsy. Science 307:81, 2005
Following the first severe outbreak of severe acute respiratory syndrome (SARS) due to coronavirus in humans in 2002–2003, a second much smaller outbreak occurred in 2003–2004. Genomic comparison of coronaviruses isolated from humans and from palm civets, the presumed source of human infection, was recently carried out by an international team of investigators. They concluded that the second outbreak was not caused by a coronavirus derived from that causing the initial outbreak, although both viruses appear to have arisen from a common ancestor. In both the civet and man, the virus is evolving rapidly, suggesting that it has not yet adapted to either host. Thus, there may be a common source of infection for man and the civet in the environment. Major genetic variations in some critical genes like the Spike gene, which encodes the S protein that binds to mammalian receptors, are essential for the change from an animal-to-human to a human-to-human transmission pattern.
Song HD, Tu CC, Zhang GW, Wang SY, Zheng K, Lei LC, Chen QX, Gao YW, Zhou HQ, Xiang H, Zheng HJ, Chern SW, Cheng F, Pan CM, Xuan H, Chen SJ, Luo HM, Zhou DH, Liu YF, He JF, Qin PZ, Li LH, Ren YQ, Liang WJ, Yu YD, Anderson L, Wang M, Xu RH, Wu XW, Zheng HY, Chen JD, Liang G, Gao Y, Liao M, Fang L, Jiang LY, Li H, Chen F, Di B, He LJ, Lin JY, Tong S, Kong X, Du L, Hao P, Tang H, Bernini A, Yu XJ, Spiga O, Guo ZM, Pan HY, He WZ, Manuguerra JC, Fontanet A, Danchin A, Niccolai N, Li YX, Wu CI, Zhao GP, Cross-host evolution of severe acute respiratory syndrome coronavirus in palm civet and human. Proc Natl Acad Sci USA 102:2430–2435, 2005
Feline infectious peritonitis (FIP) is caused by spontaneously arising virulence mutants of nonpathogenic enteric coronavirus. FIV is characterized by episodes of fever and weight loss, accompanied by dramatic decreases in CD4+ and CD8+ T cells. In a careful longitudinal study, Dutch scientists monitored body weight, rectal temperature, leukocyte counts, anti-viral titers, and viral RNA levels in plasma and leukocytes. Clinical signs of fever, weight loss, and lymphopenia were similar in all animals during the first week of infection; however the subsequent disease course was highly variable. Most animals had waves of enhanced viral replication associated with fever, weight loss, and depletion of CD4+ and CD8+ T cells. Humoral immunity did not appear to be protective. These findings suggest that virus-induced T-cell depletion and the antiviral T-cell response are opposing forces and that the outcome of the infection is determined by the balance of the two. When the cell-mediated immune system is no longer able to control viral replication, death occurs.
de Groot-Mijnes JD, van Dun JM, van der Most RG, de Groot RJ, Natural history of a recurrent feline coronavirus infection and the role of cellular immunity in survival and disease. J Virol 79:1036–1044, 2005
The nasal-associated lymphoid tissue (NALT) consists of a pair of lymphoid organs located above the soft palate of rodents that is analogous to human tonsils and adenoids. Investigators at Yale examined postnatal development of the NALT in mice and the factors that controlled this process. Although present at birth, the NALT contained very few cells. The number of lymphocytes increased over the first few weeks of life, with distinct T and B-cell zones appearing by 21 days. By this time, high endothelial venules were concentrated in the T-cell zone of the NALT and multiple lymphoid cytokines were being expressed. Lymphotoxin knockout mice (LT-β−/− or LT-α−/−) had NALTs with fewer cells than wild-type mice, reduced or absent lymphoid chemokines, reduced or absent expression of adhesion molecules on blood vessels, and no T- and B-cell compartmentalization. These data indicate that lymphotoxins contribute to NALT development and function through regulation of lymphoid chemokines and adhesion molecules.
Ying X, Chan K, Shenoy P, Hill M, Ruddle NH, Lymphotoxin plays a crucial role in the development and function of nasal-associated lymphoid tissue through regulation of chemokines and peripheral node addressin. Am J Pathol 166:135–146, 2005