Smelling a rat
The dreaded Rat fever has triggered off a panic wave in the State. But a few simple precautions will go a long way in its prevention.
RAT FEVER has raised its ignominious head yet again. Between January and September this year, the disease has resulted in 58 deaths all over the State. While 168 people were infected in Thiruvananthapuram district alone, 14 deaths have been reported.
Reports indicate that since 1998, the number of Rat fever cases reported in medical colleges all over the State have touched an average figure of 2,000 every year. Of these, seven per cent succumb to the disease.
But the big question remains -- are rats only to blame for the situation? What about us who create conditions conducive to their proliferation? The recent garbage crisis in the city is an instance.
The emphasis of preventive strategies would be on waste disposal, rodenticidal measures and public education, says the District Medical Officer, K. Shailaja.
The disease is caused by a genre of bacteria found in certain kinds of rats. Known as leptospiro (Leptospira ictero-haemorrhagiae), the bacterium belongs to the family of spirocate. Named after the scientist Dr. Weil, who discovered the disease, Leptospirosis is also known as Rat fever or Canicols fever.
The disease is transmitted from animal to animal and human being, but not from human being to human being through physical contact. The incubation period is seven to 13 days, after which the symptoms begin to surface. Early symptoms include fever, cold, headache, muscle ache and pain, loss of appetite and vomiting with prostration. The later phase may include bruising of the skin, sore eyes, photophobia, nose bleeding, reduced urine output and jaundice. The fever lasts for about five days, and may be followed by significant deterioration in health. Body temperature may shoot up to 38.90 degree Celsius in advanced stages.
Very often, the patients misjudge these symptoms for viral fever or flu and start treatment for those diseases, until the situation spins out of hand. Any delay in the right kind of treatment can cause renal failure or myocardial infarction. Within two to seven days of entering the body, the bacteria strike at the body's immune system. Untreated, they go on to affect the pancreas, liver, heart, small intestine and kidney. Bloodstains may be seen in the vomit and excreta of the victim and he may contract viral fever too.
The mortality rate among patients with these symptoms is 10 per cent. In latter stages, inflammation of the heart, lungs, and kidney may occur and the mortality rate may climb up to 40 per cent. Weil's Disease also affects the brain indirectly, resulting in a condition similar to meningitis. In pregnant women, the disease can even lead to abortion. Initially, penicillin and then other antibiotics are administered to treat rat fever and complications that entail.
The bacteria gain entry into the body through breaks in the skin such as cuts, wounds, blisters and abrasions, or through the lining of the nose, throat or alimentary tract, when they come into contact with water contaminated by the organism. Taking food polluted by the urine of the infected rat is another way in which it can be transmitted. Though the bodies of some kinds of rats such as big rats and rats found in swampy areas form the natural habitat of the disease-causing bacteria, dogs, foxes, pigs and bovines can also act as carriers of the pathogens.
Laboratory test shows that in a millilitre of urine, 10 crore bacteria can be detected. Normally, a big rat passes out seven to 10 ml of urine every day.
The infected person takes 10 to 20 days to get over the affliction. Laboratory testing of blood (serological test) does confirm the diagnosis, but the result may take time in an ordinary hospital lab. Prevention is better than cure goes the adage. To avoid contracting the disease, one should keep the premises free from rodents. Food - both cooked and raw - should be kept covered at all times to avoid rodent infestation and contamination by rat's urine. Water stagnation and piling up of garbage should not be allowed. Safe waste disposal should be ensured, and well water should be disinfected using bleaching powder or chlorine tablets. Only chlorinated water should be consumed. In case of suspicion of water contamination, it is safer to take boiled water. Avoid minor cuts and lacerations on the feet, through which the parasite may be contracted. Avoid having a dip in canals and ponds, for they may be contaminated with rat's urine. Dairy workers, veterinarians, farmers, sewer workers, abattoir workers, cane sugar and pineapple field workers should use protective wear and shoes. Pets should also be vaccinated. Also wear footwear regularly.
The leptospira bacterium is passed out from a rat's body through its urine.
It can survive only in watery medium and therefore does not live long in dry conditions.
It thrives in alkaline medium and in a temperature of 30 degree centigrade for up to 120 days. Salt water kills the organism but there is a significant risk for those living in tidal areas and near water sources such as rivers, canals, ponds or areas of slowly draining water. Weil's Disease is seemingly seasonal, since its outbreak is mostly reported during the rainy season, that is from June to November.
hough the disease is not gender biased, 77 per cent of those infected are understood to be men. About 91 per cent of the infected are between the ages of 20 and 50.
K. C. ASOK
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