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| HEALTH TRIBUNE | Wednesday, August 16, 2000, Chandigarh, India |
Journeys of living and dying When prevention is risky |
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Sleeping sickness in Nandankanan
Trypanosomiasis is a fatal disease caused by a blood protozoa called trypanosome. The disease can be compared symptomatically to malaria to a certain extent. Besides its clinical importance in animals, it has a zoonotic importance as it is communicable from animals to
man. Trypanosomiasis in man is called "sleeping sickness" in Africa and "Chagas disease" in S. America. This is transmitted from infected animals to animals, from animal to man and from man to man by blood-sucking flies, mainly the Tsetse Fly. However other insect vectors like biting flies and bugs, of blood-sucking nature, can also transmit the disease while having a blood meal on the skin of the host. Of late, Trypanosomiasis is in the news and has drawn sufficient public attention, thanks to the media for highlighting a national problem ignored so far! Trypanosomiasis has been blamed for killing 13 precious tigers by the zoo authorities at Nandankanan in Orissa. Another lobby is doubtful of trypanosomiasis and blames Berenil, the drug used as a prevention, for the fatal results. While this debate goes on and the government-style inquiries take their course, it should be interesting to know about this disease. The disease is centuries old and was first reported in 1894 by Sir David Bruce who demonstrated that this organism caused the ailment in cattle called Nagana. Eight years later, in 1902, it was shown that the same trypanosome caused human "sleeping sickness". There are some non-pathogenic species of trypanosomes in both animals and men. However, certain species show definite host specifications in animals as well as in humans according to their geographical locations. Trypanosomiasis is usually seen in tropical areas. In man its prevalence over the centuries is confined to the African countries and south America. Fortunately, the reported incidence in Asia is almost nil because of the absence of the tsetse fly and a small number of other blood sucking flies. Amongst animals, the prevalence of trypanosomiasis is not uncommon in India. Trypanosomiasis is a group of diseases caused by a protozoa of the genus Trypanosoma" with many species. Different species of trypanosome infect animals and man. So far only three species — T. evansi, T.theleri, and equiperdum have been reported from animals in India. The animals, mainly infected by trypanosome species in India in order of importance, are: cattle (buffaloes more than cows), sheep, goats, pigs, horses, camels and rarely dogs and cats. Trypanosomiasis has been reported in wild animals too. The tigers among the wild animals belong to the cat family, do suffer from this disease, though rarely, and can act as reservoirs. Wild and domestic, animals along with rats, mice, rodents, antelopes and primates, are the reservoirs for different species of trypanosomes. The involvement of an insect vector is a must in the transmission of this disease. In man, the main species of trypanosomes involved are that of commonly seen in cattle in Africa. Fortunately, the species of trypanosomes reported so far in cattle in India are not found in man. Luckily none of the three species found in Africa and S. America occur in Asian countries. The disease is also known by different names in man —Tsetse transmitted trypanosomiasis or sleeping sickness in Africa, Chagas Disease in S. America and in animals as surra in camels, dourine in horses. The transmission of trypanosomiasis is cyclical, and begins when blood from a trypanosome infected animal is ingested by blood-biting insect vectors like bugs, horse fly, kissing bugs etc. While biting the host, trypanosomes are sucked in the mid gut with the blood meal. Tryanosomes then penetrate the gut wall to reach the salivary glands where they develop into the infective form. When a new host is bitten, the infective forms of trypanosome are passed on to start a new infection. The development of these infective forms within the fly takes two to five weeks. From there, they enter the lymphnodes and then the blood stream where they divide and multiply rapidly. Some of the pathogenic species of trypanosomes can cause extensive tissue damage to several vital organs like the spleen, the liver, the heart and the nervous system. The immune response of the host probably plays an important role in the pathogenesis of this disease. Host antibodies can kill the trypanosomes but often fail because of the multiple variation in their antigenicity. This antigenic variation has prevented the development of a vaccine and often permits the reinfections when animals are exposed to a new antigenic type of trypanosomes. The severity of the disease varies with the species and the age of the host (animal or man) gets infected and the species of trypanosome is involved. The incubation period is usually one to four weeks. The primary clinical signs in animals are: intermittent fever, anaemia, and weight loss. Heart failure, jaundice and convulsions are the advanced symptoms prior to death. A presumptive diagnosis is based on finding anaemia in animals in poor condition in an endemic area. Confirmation depends on demonstrating trypanosomes in stained blood smears. Other infections that cause anaemia and weight loss, such as babesiosis, anaplasmosis, and theilerosis, should be eliminated by examining a blood smear. To reach a final diagnosis it very important to know the specie involved. Several drugs can be used. Most of these drugs have a narrow therapeutic index, which makes the administration of the correct dose essential. Drug-resistance occurs and should be considered in refractory cases. Berenil, used at the Nandankanan zoo, is one of the most widely used drugs. It should be administered preferably by deep intramuscular injection. Berenil enjoys a very low therapeutic safety index — especially in dogs and cats. And the tigers belong to the cat family. Berenil is used even in the treatment of sleeping sickness in humans. Public memory is always short. The media will forget the disease as soon as the hype is over. Tigers belong to the cat family for all reasons of treatment. In the light of the media-reported facts and the basic knowledge on trypanosomiasis as discussed above, there are many ifs, buts and whys which remain unanswered as yet: was the disease really trypanosomiasis? Which specie it belonged to? Were all the tigers monitored for trypanosomes before injecting a drug known for its bad results in cats? Was Berenil administered in the right manner? Why did the tigers not given Berenil did not die? Was the veterinary section of the zoo well equipped to handle the situation? Is Nandankanan area endemic to trypanosomiasis? Were the tigers healthy enough nutritionally, physically and immunologically? Why only tigers, why not other animals at the zoo, were considered for trypanosomes? Was Berenil given as a preventive medication to "save" other animals? If yes, what were the results? (A deer was seen dead in few pictures lying along with tigers). What was the disease surveillance status at Nandankanan since 1996? Last time a tiger was said to have died of Trypanosomiasis All said and done, the fact remains that we have lost 13 lives of a precious specie because of some error somewhere. Today it is trypanosomiasis, tomorrow it could be some other disease. Today it is Nandankanan, tomorrow it could by any other zoo. Wild animals bred and brought up in a zoo are comparable with pets reared in jungle-like conditions. In any zoo it is the disease prevention programme rather than the treatment regimen works well. For communicable disease like trypanosomiasis, for the proper control, first the correct diagnosis to the specie level and then proper surveillance in and around the zoo area is the answer. For communicable diseases, whether in man or in animals, clinical, laboratory and epidemiological findings have to get to arrive at a correct diagnosis. Failure to do so results in a colossal waste of national resources. The information given by the print media on the living conditions, government policy and figures showing death rates in zoos, is alarming. The big question remains what lessons have we learnt from this tragedy. What steps do we take to ensure this does not happen again? Will the government take the veterinary medical services at zoos more seriously? Shall we wake up? The author is a practising vet based at Chandigarh. He has worked extensively on dogs, cats and poultry. He has an additional qualification with regard to Zoonoses — the branch of veterinary medical science which deals with diseases communicable from animals to men. No more Nandankanans, please!
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Journeys of living and dying Doctors join their patients on journeys of living and dying. Medicine's central reward is to behold the lives of patients well enough to apprehend their meanings. Optimal patient-care requires more than biomedical knowledge and technical expertise. The best clinicians also bring to the bedside a thoughtful appreciation of the patient's hopes and fears, of the social and historical context of the illness, and the meaning of that illness to the patient. An appreciation for medicine's non-technical aspects develops through years of practice. I have a patient with widely spread cancer of an unknown primary cause. He has ascites, respiratory distress, pain and extreme weakness but he is arousable (not unusual). Believing that he will die in a matter of days, I am tender with him, talk softly, touch him gently and try to divert his attention from disease. I feel humbled and awed in the presence of his imminent death. Knowing the horrible diagnosis, I feel that I can be a witness to his extreme suffering. I sense the sacredness of these last days of his life. I silently join him for some time everyday, wondering at his journey. Coping with this situation is more than just a medical event. It is a process that demands partnership between bereaved persons, family members and doctors rather than simply a medical course of treatment. Close relations demand that "everything" be done. Of the fundamental needs of persons as they die, only the need to control physical symptoms is uniquely medical. They require help with personal hygiene, need nourishment, and as death comes closer, sips of fluids to moisten their mouth and throat. They need others to recognise their continued existence; they also need companionship even though they think that they are dying. The members of the family can help with words and with action: "we will keep you warm, and clean, offer you food and fluid. We will be with you and will bear witness to your pain and your sorrows, your disappointments and triumphs". The suffering of the bereaved person is often protracted and complicated. The family needs forewarning and guidance to make the most of the this time. Doctors do their best to imagine what their patients go through, using empathy to understand the patient's situation accurately. They listen to the stories the patients tell. These are made up of words, gestures, silences and findings. Doctors register the unsaid as well as the said. Medicine's reward is to behold the lives of patients well enough to apprehend their meanings. Hippocrates understood his medical effectiveness to rest on his ability to tell in quiet words and stories what his patients seemed tot have been going through. The fear and rage and need of patients close to death can change a doctor's way of caring for the sick patients. Empathy is what binds humanity together. Without this enabling factor, there can be no human society and certainly no medicine. Medicine is a profoundly social enterprise. Rudolf Virchow wrote in 1849: "Medicine is a social science in its very bone and marrow ...." Doctors need timely methods of systematically reminding themselves of the fundamental human needs of the sick people. Practising medicine requires careful attention to the psychological, cultural, and spiritual dimensions of the patients, in addition to alleviating their suffering during the last days of their lives. There is an urgent need to treat the fading patients with dignity, respect and compassion even though the end result is a dying process characterised by suffering and a feeling of helplessness on the part of the family. After witnessing a death, there comes an encounter with yet another terminal challenge. It is not given to a doctor to unburden his mind in public. His calling passes throughrelentless Fate — his own Fate too! The show must go on.... Amen. Dr Wig, FRCS, looks at his vocation as recurring trysts with ordained faith — and odds of anguish and moments of joy. He is a renowned academician and surgeon based at the PGI.
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When prevention is risky How can you prevent cancer ? This is a million-dollar question and a direct comprehensive answer to this is not possible although billions of dollars have been spent and are being spent all over the world in search of an
answer. A disease can be prevented only if you know what actually causes it. For cancer, we still do not have the answer although it is known that constant irritation to the tissue for a very long period can give rise to cancer. This irritant may be a physical or chemical agent or a microbial organism. Take for example the sun rays. Because of the ultra violet rays, they can give rise to cancer of the skin as commonly seen in Australia and New Zealand. Chemical agents like coaltar, mercury and insecticides can give rise cancer in the workers handling these to agents. But the biggest culprit is the smoking of tobacco which gives rise to lung cancer, the chewing of it leads to the cancer of the mouth and the food pipe. Because of the prevalence of tobacco chewing in India, particularly in Madhya Pradesh, Bihar, Uttar Pradesh and Andhra Pradesh, the cancer of the mouth is the commonest type seen in our country. Microbes have been also thought to be giving rise to cancer, for example Burkitt's tumour as seen in African countries. As mentioned earlier, it is not only the presence of the irritant; it should be there for a prolonged period and, therefore, time ( i.e. aging) is a major factor in the development of cancer. Although there are certain exceptions ( for example, some childhood cancers like leukaemia, brain and kidney tumours and, lymphoblastoma, can occur even in new-born children), the vast majority of the common cancers occur in the fifth and the sixth decades of life and the incidence increases further with the passage of time. It is known that we cannot stop the aging process but we can surely identify some factors in our life-style that may have a contributory role in the development of the disease and we can try to nullify their effects. Certain risk factors are known to increase the chances of developing cancer above the level of the risk in the general population. Some of the important factors are mentioned below: Genetic factors:
Breast cancer is one such example, where 5 per cent of the patients may be found to have a familial tendency. Research is going on to detect women with genetic abnormalities, who would be developing breast cancer in later part of their lives. The detection of such ladies will prompt the institution of intense screening programmes in them so as to detect cancer at the earliest stage when the treatment is expected to achieve 100 per cent cure. Recently it has been reported that the human genome had been mapped and it was hoped that in the near future in would be possible to pinpoint the chromosomal abnormality that gave rise to a particular disease. It is also hoped that genetic manipulation may be able to repair such damaged DNA so as to prevent the development of breast cancer in the genetically predisposed ladies. The same holds true for other types of cancer. In the USA, cases have been reported when ladies with strong family histories have undergone the removal of both breasts ( bilateral subcutaneous mastectomy) and reconstruction so as to prevent the development of breast cancers in them. This is not an accepted modality of management and I do not think this is recommended at present. Regular screening for breast cancer should be practised by every lady above the age of 40 to detect the disease at an early stage. Now it is not possible to prevent the disease. In addition, ovarian cancer, kidney cancer in children and retinoblastoma ( an eye tumour occurring in the retina) are the other tumours, which have a strong hereditary predisposition and children of parents who have any of these tumours should undergo very regular screening so as to detect the disease at a very early stage. It has been said: " You cannot choose your parents and hence cannot prevent these hereditary conditions but you can surely choose the right screening programme to detect the cancerous disease at the earliest and then get the best of the treatment at an early stage". Physical agents:
Similarly, in Kashmir, people during winter months keep a basket with burning coal (kangri) close to their abdominal skin for keeping themselves warm and the direct heat because of the constant irritation gives rise to the cancer of skin in the abdominal region. The preventive measure is easily understood and can be easily implemented. Professor Bose is the writer of the little "anti-cancer Bible". He is a renowned teacher and clinician. He is based at the PGI, Chandigarh. (To be continued)
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