Today we continued our presentations on diseases.
Ying presented about shingles. Shingles is caused by the Varicella zoster virus. Early signs of the infection include itching or pain in an area of the body. After a few days blisters appear in a band which often corresponds to a dermatome in the body. When herpes zoster localizes on a particular place on the body it can be referred to in a way to indicate this condition. Herpes zoster opthalmicus occurs when reactivated VZV travels down the ophthalmic branch of the trigeminal nerve and affects the eye. This form of infection can result in vision loss among other things. Herpes zoster oticus affects the inner, middle and outer ear and hearing and balance can be affected. Shingles infections usually clear in a few weeks and symptoms abate but sometimes Postherpetic Neuralgia (PHN) can occur at the sites of infection and people experience pain or itching after the blisters have healed. Almost 100% of the population has been exposed to VZV by the age of 60. These infections are usually not fatal. Vaccines are available for children (against chicken pox) and people older than 60 (for shingles). About a year ago I went to a dinner/presentation that a pharmaceutical representative hosted and the speaker was a specialist doctor who spoke about shingles (more specifically Zostavax, the shingles vaccine) and he had a pain chart ranking how painful certain conditions are. Shingles was ranked more painful than childbirth on this scale! Apparently shingles is an incredibly painful condition in its more severe forms and in addition to treating the shingles physicians must often treat the pain that the infection causes their patient.
Lannie did a presentation on herpes simplex viruses 1 and 2. Herpes is Greek for “to creep or crawl.” HSV1 is the form of this disease that causes oral herpes and HSV2 is the form that causes genital herpes. They are characterized by blisters in the affected are and an eruption can be brought on by and injury to the face, lips, eyes or mouth, trauma, surgery, menstruation, exposure to wind or sunlight. Genital herpes is often mistaken for bug bites at the 1st symptoms after exposure. The 1st outbreak of a herpes infection is often the most severe as the body is totally unprepared to fight off this new type of infection but subsequent outbreaks are usually not as bad. The herpes virus can remain active on an inanimate surface for 2-4 hours! I did not know that and also that you can get herpes on your buttocks because of this! Different strains of HSV are less virulent outside of their preferred areas of infection and infection of HSV can give limited protection against other strains of HSV. Something interesting about this is that there is a connection between the APOE-epsilon4 allele and Alzheimer disease, meaning that people with a certain genetic makeup who are exposed to HSV may be more likely to develop Alzheimer disease later in life.
Andrea chose Tasmanian Devil Facial Tumor Disease as her disease topic. This condition affects Tasmanian devils only and is an infective cancer. This disease is characterized by facial cancer or tumors found initially around the devils mouth which then spread to neck. This disease is spread from adult males to females during mating. This disease was first described in 1996 and has since wiped out up to 95% of the population of Tasmanian devils in some areas with up to 83% of trapped animals displaying signs of infection. This disease is killing the devils so fast and there has been only one reported individual who is immune to the disease that it will lead to the extinction of the species. Increased conservation strategies have been implemented to try to keep the devils from going extinct. I think that it was interesting that someone chose a disease that only affects a specific animal for their topic because most of the diseases chosen (including mine) have been ones that affect humans. Someone asked if the disease can be passed from mother to babies so I attempted to answer this question. I found that the gestation period for Tasmanians devils is 21 days and we knew that the infected devil dies within 3-8 months of exposure. I would guess that the mother dies before ever giving birth or that she is too sick to even mate during mating season. I did not find any examples of a mother giving birth to infected babies. I also read that the Tasmanian devil has always been considered a pest due to its killing of chickens and other livestock and that they were trapped or poisoned regularly amongst other methods to try to keep their numbers down. Even though they are on the endangered species list some farmers still practice poisoning the Tasmanian devils.
http://www.dpiw.tas.gov.au/inter.nsf/WebPages/BHAN-5358KH
Holly presented her blog on Grapevine Leafroll Disease. This disease is a virus affecting grape plants used to make wine. This disease is mainly transmitted differently depending on which strain of the virus it is. The grape mealybug, other scale insects and grafting all lead to incidence of the disease. The plants do not die they just have a lower yield and the leaves are deformed. The mealybugs also do not die and are asymptomatic carriers of the disease. Methods of prevention include; testing for the disease seasonally and removal of the infected vine. I was wondering why growers of these grapes don’t just use insecticides to kill the mealybugs and found some interesting information about these insects. Apparently these insects have a cotton-wool covering over their bodies which repels insecticides. A wetting agent must be added to the insecticide so the poison can penetrate the bugs covering. Also the bugs have built resistance to the poisons so different types must be used and usually prolonged times of treatment are required and this can be harmful to the plants. I also tried to find if there had been any genetic engineering of these plants for resistance but did not find any really good information.
http://www.cactus-art.biz/note-book/Dictionary/Dictionary_M/dictionary_mealy_bugs.htm
I apologize for my run-on sentences but this has always been a problem I have when writing and I have never been able to find a way to stop a sentence that is too long. AAA! I’m pretty sure that was one!
