Feline Immunodeficiency virus
By: Emily Nutt
Introduction
Approximately 1.5 to 3 percent of all healthy cats in the United States are infected with Feline Immunodeficiency Virus or FIV. Sick cats are even more likely to contract FIV since they have a 15 percent chance of contracting the virus [2]. FIV is a type of lentivirus, a retrovirus that propagates at a slow pace. This slow propogation causes a huge gap of months to years from when the cat becomes infected with the virus and when it begins to show symptoms. A more widely known lentivirus is that of Human Immunodeficiency Virus or HIV. Unlike HIV, FIV infects cats through biting that occurs during fighting. HIV and FIV infect their host T-cells in a similar manor because they are both retroviruses.
All retroviruses use reverse transcriptase to covert their RNA genome into double-stranded DNA, which is then transcribed and translated to create new virions. These types of viruses carry the protein reverse transcriptase in side the viron instead of an early gene being translated to form the protein. In fact the reverse transcriptase is already bound to the viral RNA with a primer attached before the virus infects the host cell [7]. Like all viruses, retroviruses bind a receptor protein on the host cell and fuse with the host membrane. Once the capsid has been uncoated the RNA is converted to double-stranded DNA through the reverse transcriptase. The new DNA copy then enters the nucleus and integrates into the host genome. At first the viral genome is able to replicate slowly only creating a few virions and thus not directly affecting the host. The host cell’s RNA polymerase and ribosomes create virions through transcription and translation of viral genes. The viruses are assembled and then bud out of the host cell to infect new host cells [7]. After sometime the host cell can then generate a large amount of virions, thus causing the host to show symptoms of immunodeficiency. However it is unknown how this process of rapid viral growth occurs and why viruses like FIV can infect the host for months to years without the host showing symptoms.
The structure and process of lentivirus infections characterizes the three stages of FIV infection. The first stage of FIV is during the first two to four months after infection when the infected cat shows signs of short term illness. The infected cat may show symptoms like increased body temperature, and enlarged lymph nodes [1]. This short term illness could be a result of early and sparse virion replication in the host. In the second stage of FIV, the cat appears completely healthy with no signs of illness. However in the third phase of the illness the cat expresses signs of a compromised immunsystem. Signs of immunodeficiency include; weight loss, inappetence, high body temperature, gingivitis, infected lymphnodes, and abnormal cell growth resulting in tumors [1]. The three stages of FIV are similar to that of the stages of HIV, both stages of infection are characterized by the retrovirus lifecycle. The genome of FIV reveals important viral proteins and thus potential vaccine targets, as well as showing how the virus evolved.. The evolution of the virus explains how both domestic cats and exotic or non-domestic cats were initially infected with FIV. The viral evolution also reveals how the virus has mutated to become specialized for each species of cat. Further analysis of the genome of FIV and how it relates to the evolution of the virus is described below.
The Genome of FIV
Include some current research in each topic, with at least one figure showing data.
Evolution of FIV
Include some current research in each topic, with at least one figure showing data.
Relationship of FIV to other Lentiviruses
Include some current research in each topic, with at least one figure showing data.
Conclusion
Overall paper length should be 3,000 words, with at least 3 figures.
References
Edited by student of Joan Slonczewski for BIOL 238 Microbiology, 2009, Kenyon College.
Include some current research in each topic, with at least one figure showing data.
[edit] Conclusion
Overall paper length should be 3,000 words, with at least 3 figures.
[edit] References
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