Unravelling the unknown
The article 'Fevers Of Unknown Origin' (Down To Earth, Vol 10, No 12, November 15, 2001) has evoked responses from a wide cross-section of readers. A few of them are produced here
It was a pleasure to read your article. I am a microbiologist and my area of research focuses on disease transmission through vectors and their crossing over into human population. Many of these fevers are recurrent fevers and have persisted in a single foci, while others like Ebola have emerged suddenly in unrelated parts of Africa. My research has shown that evolution pressures exist -- one at the vector level and the other at the pathogen level. Often during this gradual change, there develops an incompatibility between the two. An example of this is Ukiriri disease, a rare mosquito-borne haemmorhagic fever in African antelopes caused by a Babesia-like micro-organism. In case of this disease, cattle that has been encroaching on savannahs have developed immunity to it. When these rangelands were restored with the original antelope population, both the vector and the pathogen had lost their infectivity barring one species, the eland. Earlier the pathogen could infect almost all species of ungulates.
As a general physician in Mumbai, I have been investigating the emergence of leptospirosis for the past five years. To many physicians, even this obvious but rarely occuring disease has become a major challenge. Broad specturm antibiotics are the only effective method we have used to curtail the spread of an epidemic. But you are right in pointing out that after curtailing the infection, we do very little to identify the causative agent. This can definitely lead to resistance in a pathogen even before we know about its nature and how best we can control it.
A K NIRMAL
My compliments to Down To Earth team for its diligent field work in covering unknown fevers in India. You are right in pointing that the medical institutions like Indian Council of Medical Research ( icmr ) and National Institute of Communicable Diseases ( nicd ) have done little to carry out any extensive field survey. I was part of the first team by the Virus Research Centre, Pune, which was responsible for setting up field offices in Arcot and Jodhpur. One interesting fever that we discovered was called the 'Jamshedpur fever' -- a violent encephalitis seen in 1955-56 among adolescents in the industrial township of Jamshedpur.
I am surprised that you did not make a mention of it. In your article you mentioned the rapid evolution of virus and crossing over as the main reason for their sudden emergence. My belief is that most these viruses have a chance encounter and they often develop new weapons or improve upon existing mechanisms to cause infections. Malaria is one such example.
S K BAGCHI
I would like to draw your attention to some factual mistakes in your story. Articles published in your magazine are often discussed in the science club of our school and we do not expect such errors. In the coloured box on page 32, the temperature should have been 68-77 degree f not degree c . In the table on page 33, malaria is shown as a viral disease whereas the fact is that is a protozoan disease. Also, Q fever is rickettsial disease that rarely spreads by ticks. It spreads mostly through pathogens in urine, faeces, milk and flesh of animal. It can also be contracted by inhaling dust.
You are right in pointing out that the temperature should be in degrees f and not degrees
your site has excellent photographs....
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