...tqc tli0tri0tidctlpartfaautotadjustrighttrin0tlin0tita
p0 tfs20tlang1033tlangfe2052tlochtaf0thichtaf0tdbchta
f17tcgridtlangnp1033tlangfenp2052 Itbtfs21tlang1048tlangfe2052tlangnp1048 thichtaf0tdbchtaf17tlochtf0 VIRUSItpar SItfs21tlang1048tlangfe2052tlangnp1048 tpar tpar Stpard tql tli0tri0tidctlpartfaautotadjustrighttrin0tlin0tita
p0 Itfs21tlang1048tlangfe2052tlangnp1048 tpar tpar Stpard tql tli200tri250tidctlpartfaautotadjustrighttrin250tli
n200titap0 Itbtaf1tfs21tlang1048tlangfe2052tlangnp1048 thichtaf1tdbchtaf17tlochtf1 T4 BacteriophageSItaf1tfs21tlang1048tlangfe2052tlangn
p1048 tpar thichtaf1tdbchtaf17tlochtf1 This transmission electron micrograph shos a T4 bacteriophage, a virus that infects only bacteria and in this case only SItitaf1tfs21tlang1048tlangfe2052tlangnp1048 thichtaf1tdbchtaf17tlochtf1 Escherichia coliSItaf1tfs21tlang1048tlangfe2052tlangnp1048 thichtaf1tdbchtaf17tlochtf1 . Phages lack any reproductive machinery and rely on the apparatus of bacteria in order to replicate. They do so by athichtaf1tdbchtaf17tlochtf1 ttaching to the cell all of the bacterium ith the spidery tail fibres visible here. The tail is a sheath that contracts to inject the contents of the head, the genetic material DNA, into its host. ithin 25 minutes of infection, the bacterial apparatuthichtaf1tdbchtaf17tlochtf1 sthichtaf1tdbchtaf17tlochtf1 successfully commandeered, viral progeny fill the cell. The overcroded bacterium bursts, releasing approximately 100 ne copies of the bacteriophage. tpar tpar Stpard tqc tli200tri250tidctlpartfaautotadjustrighttrin250tli
n200titap0 Itaf1tfs21tlang1048tlangfe2052tlangnp1048 thichtaf1tdbchtaf17tlochtf1 M. urtzUniv. of BaselScience SourcePhoto Researchers, Inc.tpar Stpard tql tli200tri250tidctlpartfaautotadjustrighttrin250tli
n200titap0 Itbtaf1tfs21tlang1048tlangfe2052tlangnp1048 tpar tpar thichtaf1tdbchtaf17tlochtf1 Hepathichtaf1tdbchtaf17tlochtf1 titis B VirusSItaf1tfs21tlang1048tlangfe2052tlangnp1048 tpar thichtaf1tdbchtaf17tlochtf1 thichtf1 The hepatitis B virus HBV causes inflammation of the liver. The virus is recognizable under magnification by the round, infectious t93tlochtf1 thichtf1 Dane particlest94tlochtf1 accompanied by tube-shaped, empty viral envelopes. Manifestations of this condition include thichtaf1tdbchtaf17tlochtf1 jaundice and a flu-like illness, hile chronic infection can lead to serious pathologies such as cirrhosis and cancer of the liver. tpar Stpard tql tli0tri0tidctlpartfaautotadjustrighttrin0tlin0tita
p0 Itfs21tlang1048tlangfe2052tlangnp1048 tpar tpar Stpard tql tli200tri250tidctlpartfaautotadjustrighttrin250tli
n200titap0 Itbtaf1tfs21tlang1048tlangfe2052tlangnp1048 thichtaf1tdbchtaf17tlochtf1 AIDS VirusSItaf1tfs21tlang1048tlangfe2052tlangnp1048 tpar thichtaf1tdbchtaf17tlochtf1 The Human Immunodeficiency Virus HIV, hich can cause acquired immune dethichtaf1tdbchtaf17tlochtf1 ficiency syndrome AIDS, principally attacks T-4 lymphocytes, a vital part of the human immune system. As a result, the bodythichtf1 trquote tlochtf1 s ability to resist opportunistic viral, bacterial, fungal, protozoal, and other infection is greatly eakened. SItitaf1tfs21tlang1048tlangfe2052tlangnp1048 thichtaf1tdbchtaf17tlochtf1 Pneumocystis carinthichtaf1tdbchtaf17tlochtf1 iiSItaf1tfs21tlang1048tlangfe2052tlangnp1048 thichtaf1tdbchtaf17tlochtf1 pneumonia is the leading cause of death among people ith HIV infection, but the incidence of certain types of cancers such as B-cell lymphomas and Kaposithichtf1 trquote tlochtf1 s sarcoma is also increased. Neurological complications and dramatic eight loss, or asting, are thichtaf1tdbchtaf17tlochtf1 characteristic of AIDS, hich is endstage HIV disease. HIV can be transmitted sexually through contact ith contaminated blood, tissue, or needles and from mother to child during birth or breast-feeding. Full-blon symptoms of AIDS may not develop for mthichtaf1tdbchtaf17tlochtf1 othichtaf1tdbchtaf17tlochtf1 re than 10 years after infection. tpar tpar Stpard tqc tli200tri250tidctlpartfaautotadjustrighttrin250tli
n200titap0 Itaf1tfs21tlang1048tlangfe2052tlangnp1048 tpar Stpard tql tli0tri0tidctlpartfaautotadjustrighttrin0tlin0tita
p0 Itfs21tlang1048tlangfe2052tlangnp1048 tpar tpar Stpard tql tli200tri250tidctlpartfaautotadjustrighttrin250tli
n200titap0 Itbtaf1tfs21tlang1048tlangfe2052tlangnp1048 tpar thichtaf1tdbchtaf17tlochtf1 Rabies VirusSItaf1tfs21tlang1048tlangfe2052tlangnp1048 tpar thichtaf1tdbchtaf17tlochtf1 The rabies virus is usually transmitted to humans by a bite from an infected dog, but the bite of any animal ild or domestic is suspect in an area here rabies is presthichtaf1tdbchtaf17tlochtf1 ent. Symptoms of the disease appear after an incubation period of ten days to one year and include fever, breathing difficulties, muscle spasms, and, in later stages, an irrational fear of ater. Death almost invariably occurs ithin three days to three thichtaf1tdbchtaf17tlochtf1 ethichtaf1tdbchtaf17tlochtf1 eks of the onset of symptoms. For this reason, the emphasis of treatment is on prevention. Dogs may not be brought into the United Kingdom until a lengthy period of quarantine has elapsed, hile in the United States, domestic dogs are vaccinated yearly anthichtaf1tdbchtaf17tlochtf1 dthichtaf1tdbchtaf17tlochtf1 stray dogs are killed. tpar tpar tpar tpar SItbtaf1tfs21tlang1048tlangfe2052tlangnp1048 thichtaf1tdbchtaf17tlochtf1 Chicken Pox VirusSItaf1tfs21tlang1048tlangfe2052tlangnp1048 tpar thichtaf1tdbchtaf17tlochtf1 The spherical varicella-zoster virus VZV infects most children orldide by the age of 10. Transmitted in airborne droplets exhaled from an infected person, the virus causes a lo fever and a rash of fluid-filled blisters that begin as red spots coverithichtaf1tdbchtaf17tlochtf1 nthichtaf1tdbchtaf17tlochtf1 g most of the body and the inside of the mouth. The disease is dangerous to neborn babies, to people first infected in adulthood, and to those in hom the virus remains dormant in nerve cells, erupting as the more painful and sometimes chronic zoster shthichtaf1tdbchtaf17tlochtf1 ithichtaf1tdbchtaf17tlochtf1 ngles, later in life. VZV is a member of the herpes virus family, hich also includes the causative agents of infectious mononucleosis, roseola, and oral and genital herpes. tpar tpar tpar tpar SItbtaf1tfs21tlang1048tlangfe2052tlangnp1048 thichtaf1tdbchtaf17tlochtf1 Viral StructureSItaf1tfs21tlang1048tlangfe2052tlangnp104
8 tpar thichtaf1tdbchtaf17tlochtf1 Some bacteriophages virusesthichtaf1tdbchtaf17tlochtf1 that parasitize bacteria, SItitaf1tfs21tlang1048tlangfe2052tlangnp1048 thichtaf1tdbchtaf17tlochtf1 left,SItaf1tfs21tlang1048tlangfe2052tlangnp1048 thichtaf1tdbchtaf17tlochtf1 are quite large and elaborately structured. The T4 phage pictured here consists of five proteins and as many parts head, tail, collared neck, baseplate, and leg-like tail fibres. In contrast, an influenza virus, SItitaf1tfs21tlang1048tlangfe2052tlangnp1048 thichtaf1tdbchtaf17tlochtf1 right,SItaf1tfs21tlang1048tlangfe...
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