Adenoviridae family is made up of two viral genera which are Mastadenoviridae (which contain viruses that infect humans and other mammals)and Aviadenovirus (which contain viruses that infect birds). Adenoviruses are one of the major viruses in this family; and they have a worldwide distribution. Adenoviruses have an icosahedral shape, and they have no envelope. They […]
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Virology
Hepadnaviridae family consists of two viral genera which are Orthohepadnavirus (which contain viruses that infect humans and other mammals)and Avihepadnavirus (which contain viruses that infect birds); and these viruses are generally called hepadnaviruses. The viruses in this family include human hepatitis B virus, animal hepatitis viruses and duck hepatitis virus. Hepadnaviruses are spherical in shape,
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Virology
Polyomaviridae family contains DNA tumourviruses like the Papillomaviridae family. Polyomavirus is the only viral genera or genus in the Polyomaviridae family. They are so named because the polyomaviruses causes tumour in various organs of the body including the kidneys, ureters, bladder, brain and bones. However, there are various genotypes of viruses in this family that
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Virology
Theviral family Papillomaviridae comprises of papillomaviruses (abbreviated as PVs); and they were previously classified together with polyomavirus in the Papovaviridae family which is no longer in use in viral taxonomy for DNA containing viruses. Papillomavirus is the only viral genome in the Papillomaviridae family; and the papillomaviruses are oncogenic i.e. they are cancer-causing viruses. Human
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Virology
Poxviridae familyis a distinct family of viral genera that contain viruses that replicate in the cytoplasm of their host cells (inclusive of vertebrate and invertebrate cells). Cowpox, smallpox or variola virus, vaccinia virus and monkey pox viruses are typical examples of viruses in this family. The Poxviridae family contains viruses that infect humans, other vertebrates,
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Virology
Parvoviridae family has six (6) genera of virus which include Parvovirus, Contravirus, Erythrovirus, Dependovirus, Densovirus and Iteravirus. Parvovirus or the human parvovirus B19 is the major viral agent in this family of virus because it causes infections in humans. The family Parvoviridae also contains viruses that cause viral infection in animals. The human parvovirus B19
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Virology
DNA viruses have only the deoxyribonucleic acid (DNA) molecules as their nucleic acid; and the DNA can either be double-stranded or single-stranded as the case may be. The replication site of all DNA viruses is the nucleus of their host cell. Nevertheless, Poxviruses (which are also DNA viruses) replicate outside the nucleus of their host
Replication is defined as the process in which a cell divides to make copies of its genome or itself. Cell division or replication in viruses is different from what is obtainable in other microbes such as bacteria that mainly replicates by binary fission. Replication in viruses only occurs inside a suitable host, and in such
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Virology
As shown in Figure 1 above, a virion is composed mainly of three parts viz: the nucleic acid genome (DNA or RNA); the capsid or nucleocapsid; and the envelopes which surround the capsid or protein coat. The nucleic acid genome of a virus or virion can assume any of the following genetic composition: Viruses assume
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Virology
Viruses are infectious agents that have a simple acellular structure that is mainly made up of a protein coat or capsid and a nucleic acid genome which can either be DNA or RNA. Some viruses also have envelopes (which are lipid-containing outer membranous layer that surround the nucleocapsid in some viruses) while others lack them,
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Virology