Nov
15
Posted by Admin
West Nile Virus
In 1937, a woman in Uganda running a high fever was the first person diagnosed with West Nile virus. Since it was first identified in the United States in 1999, it has killed more than 650 people, and caused illness in more than 16,000.
West Nile, one of the flavivirus group, is carried in the blood of infected birds, notably crows, ravens, magpies, and jays. Mosquitoes that bite infected birds transmit the virus to humans through subsequent skin bites.
The disease is common in African, Middle Eastern, and Eurasian populations, but most who have the virus in their bloodstream experience only mild, flu-like symptoms such as skin rash, headache, and tiredness. Symptoms appear two to 14 days after the bite from an infected mosquito; the effects may last from a few days to several months. An estimated 80 percent of people infected, however, experience few or no ill effects at all.
In its severest form, though, the virus passes the blood-brain barrier and causes high fever, stiff neck, muscle tremors, paralysis, and brain swelling. This version, which mimics encephalitis (or "sleeping sickness"), arises in only 1 percent of those infected and can cause death within days. In recent years, there have been several outbreaks of West Nile virus in its lethal encephalitic form: in Algeria in 1994; in Romania in 1996; in the Czech Republic in 1997; in the Democratic Republic of the Congo in 1998; in Russia in 1999; and in Israel in 2000. There is no cure.
The disease was unknown in North America until 1999, when the bodies of dead crows dropped from the New York City sky. While this avian mystery was being investigated, human patients began to arrive in local hospitals complaining of fever, nausea, vomiting, and difficulty breathing. At first doctors suspected the mosquito-borne St. Louis encephalitis, but that disease doesn't kill birds so it wouldn't explain the crows' deaths. Blood tests and autopsies discovered that one pathogen had infected both birds and humans: West Nile virus.
Since its arrival, the virus has established a permanent foothold in the United States. In 2004, 2,535 cases were reported, covering all but nine states. In North America, the disease is most prevalent in late summer and early fall. In milder southern countries, West Nile virus occurs year round.
Household pets contract the disease in the same way as humans. There is no evidence that cats or dogs can transmit the virus to humans, nor is it passed through typical person-to-person contact, such as kissing or touching.
A promising new vaccine has been developed by the Cambridge, Massachusetts-based biotechnology company Acambis, which says it produced enough antibodies to fight off West Nile disease in all but one of the 60 people vaccinated in preliminary trials. A vaccine will not be ready for market for at least three years.
Because there is currently neither an approved vaccine available to prevent the disease nor treatment for it, public health officials focus on controlling the vector, or carrier. Local health departments may choose to spray insecticides in mosquito-breeding areas. Homeowners can eliminate standing water in basins, flowerpots, and other receptacles — breeding grounds for mosquitoes — as well as repair screens. Outside activity should be minimized in early mornings and evenings, when mosquitoes are most active. Repellents containing DEET deter mosquitoes when sprayed on clothes or skin. The recommended concentration of DEET is 10 percent for children and 30 percent for adults. Protective clothing covering the arms and legs is also recommended for those spending time in areas where mosquitoes are prevalent.
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Nov
15
Posted by Admin
Mesothelium
Mesothelioma is a form of cancer that is almost always caused by previous exposure to asbestos. In this disease, malignant cells develop in the mesothelium, a protective lining that covers most of the body's internal organs. Its most common site is the pleura (outer lining of the lungs and chest cavity), but it may also occur in the peritoneum (the lining of the abdominal cavity) or the pericardium (a sac that surrounds the heart).
Most people who develop mesothelioma have worked on jobs where they inhaled asbestos particles, or have been exposed to asbestos dust and fibre in other ways, such as by washing the clothes of a family member who worked with asbestos, or by home renovation using asbestos cement products. Unlike lung cancer, there is no association between mesothelioma and smoking.
* Mesothelioma: (cancer of the mesothelium) is a disease in which cells of the mesothelium become abnormal and divide without control or order. They can invade and damage nearby tissues and organs. Cancer cells can also metastasize (spread) from their original site to other parts of the body. Most cases of mesothelioma begin in the pleura or peritoneum. More than 90% of mesothelioma cases are linked to asbestos exposure.
* Intra-abdominal adhesions: Normally, the mesothelium secrets plasminogen, which removes fibrin deposits. During surgical procedures, the mesothelium may be damaged. Its fibrinlytic capacity becomes insufficient and fibrin accumulates, causing fibrous adhesions between opposing surfaces. These adhesions cause intestinal obstruction and female infertility if it occurs in the abdomen, and may impair cardiac and lung function in the thorax.
* Ultrafiltration failure: The peritoneal mesothelium is implicated in in the long-term development of ultrafiltration failure in peritoneal dialysis patients. The presence of supra-physiological glucose concentrations, acidity, and glucose degradation products in peritoneal dialysis fluids contribute to the fibrosis of the peritoneal mesothelium, either by epithelial-mesenchymal transition or increased proliferation of existing fibroblasts. A fibrosed peritoneum results in the increased passage of solutes across the peritoneum and ultrafiltration failure.
Cancer often has no specific symptoms, so it is important that you limit your risk factors and undergo appropriate cancer screening.
Nevertheless, you need to know which symptoms might point to cancer. You do not want to ignore a warning that might lead to early diCancer gives you no symptoms or signs that exclusively indicate the disease. Every complaint for cancer can explain a harmless condition as well. If you have symptoms, however, you should see a doctor for further evaluation. Some common symptoms are as follows:
* Persistent cough or blood-tinged saliva
o These symptoms usually represent simple infections such as bronchitis or sinusitis.
o They could be symptoms of cancer of your lung, head, and neck. Anyone with a cough that lasts more than a month or with blood in the mucus that is coughed up should see a doctor.
* A change in bowel habits
o Doctors sometimes see pencil-thin stools with colon cancer.
o Occasionally, cancer exhibits continuous diarrhea.
o Some people with cancer feel as if they need to have a bowel movement and still feel that way after they have had a bowel movement. If any of these abnormal bowel complaints last more than a few days, they require evaluation.
* Blood in your stool
o A doctor always should investigate blood in your stool.
o Hemorrhoids frequently cause rectal bleeding, but because hemorrhoids are so common, they may exist with cancer. Therefore, even when you have hemorrhoids, you should have a doctor examine your entire intestinal tract when you have blood in your bowel movements.
+ X-rays may be enough.
+ Sometimes, when the source of your bleeding is entirely clear, these studies may not be needed.
* Unexplained anemia
o Anemia is a condition in which you have fewer than the expected number of red blood cells in your blood. Anemia should be investigated.
o There are many kinds of anemia, but blood loss almost always causes iron deficiency anemia. Unless there is an obvious source of ongoing blood loss, as there is for menstruating women, this anemia needs to be explained.
o Many cancers can cause anemia, but bowel cancers most commonly cause iron deficiency anemia. Evaluation should include endoscopy or x-ray studies of your upper and lower intestinal tracts.
* Breast lump or breast discharge
o Most breast lumps are noncancerous tumors such as fibroadenomas or cysts. But all breast lumps need to be thoroughly investigated.
+ A negative mammogram result is not sufficient to evaluate a breast lump.
+ Generally, diagnosis requires a needle aspiration or biopsy (a small tissue sample).
+ Discharge from a breast is common. But some forms of discharge may be signs of cancer. If discharge is bloody or from only 1 nipple, further evaluation is recommended.
o Women are advised to conduct monthly breast self-examinations.
* Lumps in the testicles
o Most men (90%) with cancer of the testicle have a painless or uncomfortable lump on a testicle.
o Some men have an enlarged testicle.
o Other conditions, such as infections and swollen veins, can also cause changes in your testicles, but you should have any lump evaluated.
o Men are advised to conduct monthly testicular self-examinations.
* A change in urination
o Urinary symptoms can include frequent urination, small amounts of urine, and slow urine flow.
o These symptoms can be caused by urinary infections or, in men, by an enlarged prostate gland.
+ Most men will suffer from harmless prostate enlargement as they age, and will often have these urinary symptoms.
+ These symptoms may signal prostate cancer.
+ Men experiencing urinary symptoms need a bit of investigation, probably including a specific blood test called a PSA and a digital rectal exam.
o Cancer of the bladder and pelvic tumors can also cause irritation of the bladder and urinary frequency.
* Blood in the urine
o Hematuria or blood in the urine can be caused by urinary infection, kidney stones, or other causes.
o For some people, it is a symptom of cancer of the bladder or kidney.
o Any episode of blood in the urine should be investigated.
* Hoarseness
o Hoarseness not caused by a respiratory infection or that lasts longer than 3-4 weeks should be evaluated.
o Hoarseness can be caused by simple allergy or by vocal cord polyps, but it could also be the first sign of cancer of the throat.
* Persistent lumps or swollen glands
o Lumps most frequently represent harmless conditions. But your doctor should examine any new lump or a lump that won’t go away.
o Lumps may represent cancer or a swollen lymph gland related to cancer.
o Lymph nodes swell from infection and other causes and may take weeks to shrink again.
o A lump or gland that remains swollen for 3-4 weeks should be evaluated.
* Obvious change in a wart or a mole
o Multicolored moles that have irregular edges or bleed may be cancerous.
o Larger moles are more worrisome.
o Removing a mole is simple. You should remove any suspicious mole. The doctor will diagnosis and possibly to a cure.
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