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The Viruses
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Viruses are classified into a variety of families based on morphologic, structural, and genetic characteristics, including the size, structure, and type of their nucleic acid (Table 16.1). The names of virus families end in the suffix viridae, for example paramyxoviridae. Viruses are classified further by the organization and function of their genetic coding and regulatory sequences, and also by the functions of specifically encoded enzymes and protein antigens. These subdivisions are called genera and end in the suffix virus such as the morbillivirus genus of the paramyxoviridae. Viruses in genera are often further divided into viral species based on differences in their genomic sequences. For example, canine distemper virus is a member of the morbillivirus genus in the family paramyxoviridae. Some human and animal viruses classified by family are listed in Table 16.1.
Measles and its neurological complications
Published in Avindra Nath, Joseph R. Berger, Clinical Neurovirology, 2020
Benedikt Weissbrich, Jürgen Schneider-Schaulies
Measles virus (MV) is a member of the Mononegavirales group, which comprises the Rhabdo-, Filo-, and Paramyxoviridae [2]. As a paramyxovirus, MV possesses structural and biochemical features associated with this group, however it lacks a detectable virion-associated neuraminidase activity. Therefore, it has been grouped into a separate genus, the morbilliviruses. Other members of this group include rinderpest virus, which infects cattle; peste des petits ruminants, which infects sheep and goats; canine distemper virus, which infects various carnivores; phocine distemper virus; dolphin morbillivirus; and porpoise morbillivirus. All these viruses exhibit antigenic similarities, and produce similar diseases in their host species, but their neuroinvasiveness differs considerably. Whereas canine distemper virus causes neurological disease in approximately 50% of infected dogs, MV causes encephalomyelitis in about 0.1% of cases.
Autoimmunity and Immune Pathological Aspects of Virus Disease
Published in Irun R. Cohen, Perspectives on Autoimmunity, 2020
H. Wege, R. Dörries, P. Massa, R. Watanabe
Canine distemper virus (CDV) infections can develop into a chronic demyelinating disease which affects dogs and other canine species.43,54 Similar to measles, acute canine distemper is associated with signs of respiratory and gastrointestinal disease. Experimental infection of dogs with certain virus strains (Cornell A75-17 or Ohio R252) leads to diseases associated with predominant white matter lesions and variable neurological signs. Within 8 to 10 days, virus can enter the brain via infected lymphocytes, and demyelinative foci develop 14 to 16 days later. A severe involvement of lymph organs leads to lymphopenia, and, therefore, no pronounced inflammatory lesions are found in the brain in this stage of disease. A severe transient depression of the immune response is indicated by a reduced response of lymphocytes to lectins. The development of antiviral immunity influences the further course of disease.54-58 Inflammatory demyelinating CNS lesions are a typical finding in CDV infections which develop a chronic course.
Role of environmental factors in multiple sclerosis
Published in Expert Review of Neurotherapeutics, 2021
Amin Zarghami, Ying Li, Suzi B. Claflin, Ingrid van der Mei, Bruce V. Taylor
There is limited evidence for the effect of other viral agents on the risk of MS onset. However, there is some evidence that three additional viruses may affect MS onset risk: canine distemper virus (CDV), hepatitis C, and human immunodeficiency virus (HIV). Elevated seroprevalence of CDV among PwMS compared with controls was first reported in the late 1970s [169]. A 2020 cross-sectional study (n = 73 PwMS) provided evidence for an age-related association between CDV and MS onset, with each decade increase from 20 to 50 years of age associated with elevated anti-CDV IgG among MS cases compared with controls [170].
In vivo nose-to-brain delivery of the hydrophilic antiviral ribavirin by microparticle agglomerates
Published in Drug Delivery, 2018
Alessandro Giuliani, Anna Giulia Balducci, Elisa Zironi, Gaia Colombo, Fabrizio Bortolotti, Luca Lorenzini, Viola Galligioni, Giampiero Pagliuca, Alessandra Scagliarini, Laura Calzà, Fabio Sonvico
The nasal route has been extensively studied for the administration of drugs directly to the CNS (Landis et al., 2012). In fact, this route exploits the olfactory region and the trigeminal nerve pathway to enable drugs’ entry into the CNS bypassing the BBB (Hanson & Frey, 2008). This delivery approach was explored for the administration of ribavirin (RBV), in view of an innovative treatment of the encephalitis associated with canine distemper virus, a major veterinary infection that could serve as a proof of concept of the approach. This virus belongs to the Morbillivirus genus as the measles virus and primarily infects dogs (Elia et al., 2008; Dal Pozzo et al., 2010). RBV is a synthetic guanosine antiviral analog. It has a broad-spectrum antiviral activity, being clinically effective against several viruses and successfully tested in vitro against several RNA and DNA virus infections (Beaucourt & Vignuzzi, 2014). The drug is currently marketed in oral dosage forms; however, it has been clinically administered as pulmonary aerosol in the treatment of respiratory syncytial virus (Li et al., 2012) and for the therapy of measles pneumonia (Safdar et al., 2009) as well as intravenously and intraventricularly for subacute sclerosing panencephalitis (Tomoda et al., 2003; Garg, 2008). However, the latter two approaches are plagued by adverse effects and exploit a highly invasive, risky, and infection-prone administration route, remarkably fostering the development of an alternative delivery route such as nasal administration. Our group showed that measurable brain concentrations of RBV can be obtained in rats after intranasal administration of a RBV aqueous solution. In particular, it was evidenced that 20 min after nasal administration, RBV was highly concentrated in the olfactory bulb and in other brain structures after nasal administration (Colombo et al., 2011).