Virus%20host%20interractions_%20phage%20host%20range%20and%20cultivation%20f%20viruses - HOST-PARASITE RELATIONSHIP IN VIROLOGY The competition for

Virus%20host%20interractions_%20phage%20host%20range%20and%20cultivation%20f%20viruses

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HOST-PARASITE RELATIONSHIP IN VIROLOGY The competition for supremacy that takes place between the host and the parasite is referred to as host-parasite relationship Accordingly, the host may have the upper hand and remains healthy or loses the competition, and a disease develops. Human parasites are either unicellular (protozoa) or multicellular (helminthes and arthropods). The parasites may live inside the host (endoparasites) or on the host surface (ectoparasites). Viruses are unicellular and live inside the host Endoparasites are classified into intestinal, atrial or they may inhabit body tissues causing serious health problems. Ectoparasites are arthropods that either cause diseases, or act as vectors transmitting other parasites. Human evolution and parasitic infections Viruses can invade the human body in different ways Through oral route Through skin Through sexual contact. Inhalation Bite by antropods Host defense mechanisms consist of innate immunity which mediates initial protection against infection and adaptive immunity which is more effective. Once parasites have evaded innate host defenses, adaptive cellular and humoral immune responses are promoted against a wide array of antigenic constituents. Diagnosis of virologic diseases depends on several laboratory methods, imaging techniques and endoscopy in addition to clinical picture and geographic location. Viral diseases may be presented by a wide variety of clinical manifestations according to the tissue invaded. Direct microscopy is based on detection of the virus by examination of different specimens (stool, urine, blood, CSF and tissue biopsies) Immunodiagnostic techniques include antigen and antibody-detection assays. Molecular-based diagnostic approaches offer great sensitivity and specificity. Recently,
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Nanotechnology can be applied as diagnostic procedures utilizing nanodevices. Control and prevention of viral diseases depend on the interactions among many factors such as the environment, the human behavior, and socio-cultural factors that determine their transmission and persistence Viruses are an obligatory parasite that is completely dependent on its host and can’t survive PHAGE HOST RANGE The host range of a bacteriophage is defined by what bacterial genera, species and strains it can lyse It is one of the defining biological characteristics of a particular bacterial virus. Because of host factors such as masking by O antigens that affects injection and the presence of restriction endonucleases, the relative efficiency of plating (EOP), that is, the titer of the phage on a given bacterial cell line compared to the maximum titer observed, may vary considerably.
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