Viral respiratory diseases

Role of neuromedin B and its receptor in the innate immune responses against influenza A virus infection in vitro and in vivo

The peptide neuromedin B (NMB) and its receptor (NMBR) represent a system (NMB/NMBR) of neuromodulation. Here, it was demonstrated that the expression of NMBR in cells or murine lung tissues was clearly upregulated in response to H1N1/PR8 influenza A virus infection. Furthermore, the in vitro and in vivo activities of NMB/NMBR during PR8 infection were investigated. It was observed that A549 cells lacking endogenous NMBR were more susceptible to virus infection than control cells, as evidenced by the increased virus production in the cells. Interestingly, a significant decrease in IFN-α and increased IL-6 expression were observed in these cells. The role of this system in innate immunity against PR8 infection was probed by treating mice with NMB. The NMB-treated mice were less susceptible to virus challenge, as evidenced by increased survival, increased body weight, and decreased viral NP expression compared with the control animals. Additionally, the results showed that exogenous NMB not only enhanced IFN-α expression but also appeared to inhibit the expression of NP and IL-6 in PR8-infected cells and animals. As expected, opposing effects were observed in the NMBR antagonist-treated cells and mice, which further confirmed the effects of NMB. Together, these data suggest that NMB/NMBR may be an important component of the host defence against influenza A virus infection. Thus, these proteins may serve as promising candidates for the development of novel antiviral drugs.

In vitro anti-influenza virus effect of total flavonoid from Trollius ledebouri Reichb

Objective

To investigate the in vitro antivirus effect of total flavonoid from Trollius ledebouri Reichb (TFTLR).

Methods

Madin-Darby canine kidney (MDCK) and Human epithelial type 2 (HEp-2) cell lines were used to test the antivirus effect of TFTLR on nine virus subtypes: four H1N1, one H3N2, and four other subtypes prevalent in North China. Tamiflu, Ribavirin and Lianhua Qingwen were used as active comparators. Comprehensive molecular pathway analyses of TFTLR-H1N1 and TFTLR-H3N2 relationships were also conducted.

Results

TFTLR inhibited MDCK cell lesions induced by H1N1 subtypes (A/FM1/1/47, A/Puerto Rico/8/1934 H1N1, A1/Tianjin Jinnan/15/2009, and A/Brisbane/59/2007) and by the H3N2 Brisbane/10/2009 strain. TFTLR inhibitory concentration (IC)₅₀ values against these viruses were 0.13, 0.07, 0.06, 0.14, and 0.07 mg/ml, respectively; and therapeutic index (TI) values were 8.62, 16.0, 18.67, 8.0, and 16.0, respectively. TFTLR showed no effect on parainfluenza virus type 1, herpes simplex virus type 1, respiratory syncytial virus, and coxsackie group B virus type 4. Pathway analysis revealed possible functional therapeutic mechanisms for TFTLR against H1N1 and H3N2 infections.

Conclusion

TFTLR may represent a potential therapeutic agent against influenza A subtypes H1N1 and H3N2 that are prevalent in North China, and should be investigated further.

Feline infectious pneumonia: a short literature review and a retrospective immunohistological study on the involvement of Chlamydia spp. and distemper virus

A short literature review of feline infectious pneumonia, feline Chlamydia and Paramyxoviridae is presented. In a retrospective study (from 1987 to 1996) 245 cases of feline pneumonia or conjunctivitis/rhinitis were investigated: histological diagnoses and aetiologies were compared; all lungs were examined immunohistologically for the occurrence of chlamydia and of canine distemper virus (CDV), but neither pathogen could be demonstrated. The results confirm previous reports indicating that feline chlamydia is not a primarily pulmonary pathogen and that CDV is not a causative agent of pneumonia in cats as it is in large felids. The review provides a summary of the known causes and pathology of infectious pneumonia in cats (in order of frequency), although some remain aetiologically uncertain. It focuses on chlamydia and distemper virus - a recognized and as yet unknown cause of feline pneumonia. The role and especially the frequency of chlamydia as a cause of feline pneumonia are controversial but distemper virus, known to cause pneumonia in dogs and large felids, has not as yet been demonstrated in cats. The aims of the retrospective study were to determine the occurrence of chlamydia in 245 cases of feline pneumonia or conjunctivitis/rhinitis, and to investigate the presence of CDV in these lungs.

Pathogenesis and treatment of feline rhinitis

Diagnosis and treatment of feline rhinitis, like canine rhinitis, can be a frustrating experience for the veterinary practitioner. Having sound knowledge of the possible etiologies involved and using a systematic diagnostic approach makes the workup of these challenging cases much easier. Selection of appropriate therapy based on a definitive diagnosis makes treatment rewarding. This article discusses the pathogenesis and treatment of a variety of causes of feline rhinitis.

Pathogenesis and treatment of canine rhinitis

Unless a systematic approach is used, evaluation of a patient with rhinitis can be frustrating to the veterinary practitioner. A complete differential list for canine rhinitis should include infectious, inflammatory, neoplastic, and traumatic causes. Other causes of rhinitis include dental disease, parasitic infestation, and ciliary dyskinesia. Diagnostic techniques that should be considered when evaluating a patient with rhinitis include obtaining a complete history, performing a thorough physical and oral examination, evaluating the patient's coagulation abilities, cytology and culture of exudate, nasal radiographs, and rhinoscopy. This article describes the pathogenesis and treatment of the various causes of canine rhinitis.