A disease can be defined as an impairment of the normal state or functioning of the body as a whole or of any of its parts. Some diseases are acute, producing severe symptoms that terminate after a short time, e.g., pneumonia; others are chronic disorders, e.g., arthritis, that last a long time; and still others return periodically and are termed recurrent, e.g., malaria.
Diseases can be categorized in two types :
- Communicable diseases (Infectious diseases)
These diseases spread from one organism to another. They may be water borne or air borne diseases. They are caused by attack of microbes such as bacteria, fungi or protozoans and viruses.
- Non communicable diseases (Non-Infectious diseases)
The diseases which do not spread from infected person to healthy person are known as non-communicable diseases. e.g., diabetes, arthritis, heart disease, cancer etc.
- COMMUNICABLE DISEASES
Malaria in humans is caused by one of four protozoan species of the genus Plasmodium: P. falciparum, P. vivax, P. ovale, or P. malariae. All species are transmitted by the bite of an infected female Anopheles mosquito. Occasionally, transmission occurs by blood transfusion, organ transplantation, needle-sharing, or congenitally from mother to fetus. Although malaria can be a fatal disease, illness and death from malaria are largely preventable.
The name malaria was proposed by Macculoch (1827). C.L.A. Laveran (1880), a French physician, discovered the Malarial parasite – Plasmodium in the blood of malaria patient. He received Nobel Prize for this discovery in 1907. Sir Ronald Ross (1887), a British physician, confirmed that malaria is caused by malarial parasite and mosquito is the vector. He received Nobel Prize for this discovery in 1902.
|Malaria is a communicable disease. It spreads from infected person to healthy person (hosts) by the bite of female Anopheles mosquitoes (vectors). The only way to prevent malaria is to prevent mosquitoes from biting. We can protect us from the bite of mosquitoes by following methods :
l Wire-gauze should be used on doors and windows of our houses to prevent entry of mosquitoes.
l Insect-repellents (e.g., Odomas) should be used to prevent mosquito-bite.
l We should sleep under mosquito net.
l Mosquito larvae should be killed by sprinkling kerosene oil on large-sized water bodies. Some larvivorous fishes such as Gambusia, minnows or trouts or birds (e.g., ducks) can be introduced in water bodies. These animals feed on mosquito larvae and hence larvae get killed and population of mosquitoes is checked. This is called biological control of mosquito.
l Adult mosquitoes can be killed by spraying insecticides (e.g., BHC, malathion). Insecticides are chemical poisons (toxicants), hence, regulation of mosquito population by them is called chemical control. Now, the insecticide DDT is not used in chemical control of mosquitoes, since, it persists in environment for much longer time and cause toxicity by accumulation in the body of fishes, birds and humans through food chains.
l The breeding grounds should be destroyed. Thus, the ditches, puddles or swamps around human dwellings should be drained or filled. We should not allow the collection of water in any uncovered container such as water tank, pot, cooler, flower pot, etc.
A drug named quinine, which is extracted from the bark of Cinchona tree, is used to treat a person suffering from malaria. This drug kills most of the stages of malarial parasite. There are certain other drugs (medicines) which should be taken on the advice of doctor. Scientists are trying hard to develop an antimalarial vaccine.
l Influenza, commonly known as the flu or the grippe, is a contagious disease of the upper airways and the lungs, caused by an RNA virus of the orthomyxoviridae family. It rapidly spreads around the world in seasonal epidemics, killing millions of people in pandemic years and hundreds of thousands in nonpandemic years.
l Influenza was first described by Hippocrates as early as 412 B.C., and the tiny virus has spent the succeeding centuries shifting, drifting and wreaking havoc. Humanity has been seeking ways to eliminate the threat since the first pandemic was recorded in 1580.
Known flu pandemics
l Fatigue/Sore joints
l Dry cough
l Sore throat
l Irritated eyes
l Body aches
l Extreme coldness
Influenza’s effects are much more severe than those of the “cold“, and last longer. Recovery takes about one to two weeks. Influenza can be deadly, especially for the weak, old or chronically ill. Some flu pandemics have killed millions of people.
There is no effective control for influenza. However, vaccines are used for the control of infection and antiviral drugs are used for cure. Amantadine and Rimantidine are recommended for the treatment of influenza. Rest hastens the recovery.
JAUNDICE / HEPATITIS
Jaundice is not actually a disease itself. Rather, it is a manifestation of an underlying problem.
The word jaundice is derived from the French word for yellow: “jaune” and refers to a yellowish colour of the skin and eyes. It is caused by a build-up of bilirubin in the body tissues. Bilirubin is a pigment which is formed as a natural process when haemoglobin (the oxygen-carrying component of blood) is metabolised. Any disease affecting the liver, the bile ducts or the breakdown of red blood cells, can cause an accumulation of bilirubin and lead to jaundice.
Jaundice or hepatitis is the disease of liver. Since liver is a very important organ in body, so its inflammation due to jaundice affects digestion adversely. Jaundice is caused by viral infection. The types of hepatitis are ; Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D, Hepatitis E or Hepatitis G. Except for type B which is a DNA virus, all the other are RNA viruses. Hepatitis is spread mostly by food and water contaminated with hepatitis virus.
Some of the more common and more important causes of jaundice are described below:
Jaundice in newborn babies is very common and is mostly a normal event. It can occur for two reasons:
Newborn babies have too many red blood cells which contain haemoglobin. It is normal for the baby’s body to break down these excess red blood cells and thus form a large amount of bilirubin.
A newborn’s liver is underdeveloped or immature and therefore cannot process the bilirubin as quickly as an adult.
Hepatitis A is an acute infectious disease of liver which affects mainly children and young adults. Transmission of hepatitis A virus (HAV) takes place by faecal-oral route, i.e., infection of HAV takes place by ingestion of contaminated water, food or milk.
l High temperature, headache, fatigue, general weakness, and joint pains.
l Loss of appetite (called anorexia) with a feeling of nausea and vomiting.
l Appearance of irritating rashes on body.
l Dark yellow urine.
l Light coloured stool after 3 to 10 days of infection.
For avoiding infection of hepatitis A following preventive measures should be taken.
l Use chlorinated, boiled and ozonised water.
l Proper cleaning of hands after handling bed and vessels of the patient.
l Hepatitis-A vaccine should be taken to prevent the disease.
(1) Application of interferon injection on the advice of the doctor will control the disease. (2) For an early cure, it is essential that patient of jaundice should take adequate rest. (3) Patient of jaundice should take high calorie diet such as juice of sugarcane, radish with gur (jaggery). (4) Consumption of protein and fat should be limited.
Hepatitis B is also known as serum hepatitis or transfusion hepatitis. This is most dangerous and widespread type of viral hepatitis. It occurs due to infection of hepatitis B virus (HBV). HBV is a blood borne DNA virus. The infection of HBV is transmitted by infected blood, inoculation (Inoculation means the introduction of a vaccine into a living being to confer immunity), from mothers to their babies and by sexual route (through the semen, saliva, etc.). Main symptoms of hepatitis B include progressive liver disease, chronic active hepatitis and hepatocellular carcinoma (i.e., malignant cancer of liver cells). Infection of HBV can be prevented by avoiding risky particles such as free or promiscuous sex (Promiscuous means sexual contact which is not restricted to one sexual partner), injectable drug abuse and direct or indirect contact with blood, semen and other body fluids of patients of hepatitis B. Hepatitis B vaccine should be taken to prevent disease.
Treatment of jaundice
Treatment, if possible, would be of the underlying cause. As mentioned above, not all of the causes of jaundice are treatable.
In cases where there is a very high level of bilirubin, usually from a bile outflow obstruction, a patient may experience severe generalised itching.
Contracted through being bitten or scratched by an animal infected with rabies virus; once in human body, virus may be neutralized or may attack central nervous system, causing Fever, irrational behaviour, and violent spasms of the throat made worse by sight of water; without intensive care in hospital (which may involve tracheotomy, artificial ventilation, and sedation), dehydration can cause death within a few days. Only 1 in 10 people bitten by a rabid animal actually develop rabies, but complacency on this score is dangerous since incubation can take anything from 2 weeks to 2 years.
The bite of a rabid dog (mad dog) and some other rabid mammals such as monkeys, cats or rabbits may cause rabies, which is fatal. Rabies is a viral disease caused by a rabies virus which is bite of the rabid animal. Disease is not expressed after infection even up to 1 to 3 months.
Rabies is characterized by severe headache, high fever, painful contraction of restless, does excessive salivation, has a chocking feeling and finds difficulty in taking in even liquid food. Since patient develops fear of water, the disease is also called hydrophobia.
(1) Cleaning the wound with carbolic soap and clear water immediately after the dog bite is an important preventive measure. (2) Any antiseptic medicine (e.g., Savalon, Dettol) should be applied to the wound caused by dog bite. (3) A doctor should be immediately consulted for application of anti-rabies vaccine to the patient. (4) Compoulsory immunization of stray doges and cats should be done. Pet dogs should be vaccinated with anti-rabies vaccine. (5) A rabid animal shows excessive salivation and tries to seek isolation after bite. Such mad animals should be killed.
Rabies can be treated with Pasteur’s treatment (discovered by Louis Pasteur), in which a course of 14 vaccines was given. Currently 5 anti-rabies vaccines are prescribed at an interval of 0–3–7–14–30 day of dog bite.
Acquired immunodeficiency syndrome or acquired immune deficiency syndrome (AIDS or Aids) is a collection of symptoms and infections resulting from the specific damage to the immune system caused by infection with the human immunodeficiency virus (HIV), the late stage of which leaves individuals prone to opportunistic infections and tumours. Although treatments for AIDS and HIV exist to slow the virus’ progression, there is no known cure.
HIV is transmitted through direct contact of a mucous membrane or the bloodstream with a bodily fluid containing HIV, such as blood, semen, vaginal fluid, preseminal fluid or breast milk. This transmission can come in the form of: penetrative (anal or vaginal) sex; blood transfusion; contaminated needles; exchange between mother and infant during pregnancy, childbirth, or breastfeeding; or other exposure to one of the above bodily fluids.
Figure 5. 1 Structure of AIDS virus.
AIDS disease spreads among human beings by the following ways :
l The AIDS disease usually spreads through unprotected (i.e., without the use of condoms) sexual contact with the infected person carrying AIDS virus. Thus, AIDS is a sexually transmitted viral disease.
l The AIDS disease also spreads through the transfusion of blood contaminated with AIDS virus.
l The AIDS disease also spreads through the use of infected needles for injections (i.e., sharing of infected injection needles which have not been sterilized).
l An AIDS infected mother can transmit the virus to her child during pregnancy or during birth (i.e., by mother’s blood).
AIDS was first detected in USA in 1981 and in India, first confirmed evidence of AIDS infection came in April 1986 from Tamil Nadu. The AIDS disease has spread in epidemic form in Africa and western countries. This is because of the undesirable sexual partners, polygamy and polyandry. Recently, a alarmed increase in the cases of AIDS have been reported from different parts of India.
Some important symptoms of AIDS are the following : swollen lymph nodes; regular fever; sweating at night and weight loss. AIDS virus causes severe damage to brain and may lead to loss of memory, ability to speak and of clear thinking.
Prevention and control
So far no medicine or vaccine has been developed to cure AIDS, so, once a person gets AIDS, he is sure to die in a short span of time. The following steps may help in controlling infection of this dreaded disease :
l People should be educated about AIDS transmission.
l Disposable syringes and needles should be used for injection.
l Sexual contact with unknown people should be avoided.
l High risk groups should refrain from donating blood.
l Before receiving blood for transfusion, one should ensure that it has been screened for HIV.
l The common razor at the barber’s shop should not be used (both for hair cuts and shaving).
Sexually transmitted infections (STI) increase the risk of HIV transmission and infection because they cause the disruption of the normal epithelial barrier by genital ulceration and/or microulceration; and by accumulation of pools of HIV-susceptible or HIV-infected cells (lymphocytes and macrophages) in semen and vaginal secretions. Epidemiological studies from sub-Saharan Africa, Europe and North America have suggested that there is approximately a four times greater risk of becoming HIV-infected in the presence of a genital ulcer such as caused by syphilis and/or chancroid; and a significant though lesser increased risk in the presence of STDs such as gonorrhoea, chlamydial infection and trichomoniasis which cause local accumulations of lymphocytes and macrophages.
Transmission of HIV depends on the infectiousness of the index case and the susceptibility of the uninfected partner. Infectivity seems to vary during the course of illness and is not constant between individuals. Women are more susceptible to HIV-1 infection due to hormonal changes, vaginal microbial ecology and physiology, and a higher prevalence of sexually transmitted diseases. People who are infected with HIV can still be infected by other, more virulent strains.
During a sexual act, only condoms, be they male or female, can reduce the chances of infection with HIV and other STIs and the chances of becoming pregnant. The best evidence to date indicates that condom use reduces the risk of heterosexual HIV transmission by approximately 80 per cent. The effective use of condoms and screening of blood transfusion in North America, Western and Central Europe is credited with the low rates of AIDS in these regions.
Exposure to infected body fluids
This transmission route is particularly important for intravenous drug users, haemophiliacs and recipients of blood transfusions and blood products. Sharing and reusing syringes contaminated with HIV-infected blood represents a major risk for infection with not only HIV but also hepatitis B and hepatitis C. Needle sharing is the cause of one third of all new HIV-infections and 50% of hepatitis C infections in Northern America, China and Eastern Europe.
The risk of transmitting HIV to blood transfusion recipients is extremely low in developed countries where improved donor selection and HIV screening is performed. However, according to the WHO, the overwhelming majority of the world’s population does not have access to safe blood and “between 5% and 10% of HIV infections worldwide are transmitted through the transfusion of infected blood and blood products”.
Mother to Child Transmission (MTCT)
The transmission of the virus from the mother to the child can occur in utero during the last weeks of pregnancy and at childbirth. In the absence of treatment, the transmission rate between the mother to the child during pregnancy, labour and delivery is 25%. However, when the mother has access to antiretroviral therapy and gives birth by caesarean section, the rate of transmission is just 1%. A number of factors influence the risk of infection, particularly the of the mother at birth. Breastfeeding increases the risk of transmission by 10–15%. This risk depends on clinical factors and may vary according to the pattern and duration of breast-feeding.
Various forms of alternative medicine have been used to try to treat symptoms or to try to affect the course of the disease itself, although none are a substitute for conventional treatment. In the first decade of the epidemic when no useful conventional treatment was available, a large number of people with AIDS experimented with alternative therapies. The definition of “alternative therapies” in AIDS has changed since that time. Then, the phrase often referred to community-driven treatments, not being tested by government or pharmaceutical company research, that some hoped would directly suppress the virus or stimulate immunity against it. These kinds of approaches have become less common over time as the benefits of AIDS drugs have become more apparent.
Examples of alternative medicine that people hoped would improve their symptoms or their quality of life—include massage, herbal and flower remedies and acupuncture; when used with conventional treatment, many now refer to these as “complementary” approaches. None of these treatments has been proven in controlled trials to have any effect in treating HIV or AIDS directly. However, some may improve feelings of well-being in people who believe in their value. Additionally, people with AIDS, like people with other illnesses such as cancer, sometimes use marijuana to treat pain, combat nausea and stimulate appetite.
- TUBERCULOSIS (T.B.)
Tuberculosis (TB) is a disease caused by bacteria called Mycobacterium tuberculosis. The bacteria usually attack the lungs. But, TB bacteria can attack any part of the body such as the kidney, spine, and brain. If not treated properly, TB disease can be fatal. TB disease was once the leading cause of death in the United States.
TB is spread through the air from one person to another. The bacteria are put into the air when a person with active TB disease of the lungs or throat coughs or sneezes. People nearby may breathe in these bacteria and become infected.
However, not everyone infected with TB bacteria becomes sick. People who are not sick have what is called latent TB infection. People who have latent TB infection do not feel sick, do not have any symptoms, and cannot spread TB to others. But, some people with latent TB infection go on to get TB disease.
People with active TB disease can be treated and cured if they seek medical help. Even better, people with latent TB infection can take medicine so that they will not develop active TB disease.
Tuberculosis was first discovered by German scientist Robert Koch in 1882. He was awarded Nobel Prize for this discovery in 1905. T.B. is an infectious disease which is communicated from one person to another directly or indirectly. Tuberculosis is also contracted from animals (e.g., cattle). Tuberculosis is caused by a bacterium called Mycobacterium tuberculosis. The bacterium releases a toxin called tuberculin. T.B. can affect all parts of body such as lungs, lymph glands, bones, intestine, etc. In human beings, the infection of T.B. spreads by inhaling infected droplets released through coughing, sneezing, talking and spitting by the patient. The incubation period of T.B. includes a few weeks to a few years.
The patient of tuberculosis feels sick and weak. There is a loss of appetite and weight. Typical fever pattern and night sweats are also common. The symptoms of T.B. vary depending on the site of the infection (disease) in the body. There are following two specific sites of tuberculosis infection.
Lung or pulmonary T.B.
The person suffered with pulmonary T.B. has continuous fever, persistant cough and produces blood stained sputum. There is loss of weight and weakness. The chest-pain and breathlessness are common features of patients of lung T.B. When the tuberculosis bacteria get into the lungs, they set up a local inflammation and produce and abscess. This usually heals up and leaves a small patch of scar tissue which shows up in X-rays photographs. In advanced stages of tuberculosis large areas of the lungs are destroyed.
Lymph gland T.B.
Symptoms of T.B. of lymph gland include swelling and tenderness of lymph glands, often in the leg which may discharge secretion through the skin.
Vigorous public health measure are the best method of prevention. Other preventive measures include isolation and proper rehabilitation of the patient. Avoidance of over-crowding, provision of good ventilation and better nutrition help to reduce the incidence of the disease.
Immunisation with BCG or Bacillus-Calmette-Guerin vaccination prevents tuberculosis. BCG vaccine contains weakened tuberculosis bacterium and it is injected into the skin of a person to give immunity for 3 to 5 years.
Symptoms of TB
Depend on where in the body the TB bacteria are growing. TB bacteria usually grow in the lungs. TB in the lungs may cause symptoms such as
l a bad cough that lasts 3 weeks or longer
l pain in the chest
l coughing up blood or sputum (phlegm from deep inside the lungs)
Other symptoms of active TB disease are
l weakness or fatigue
l weight loss
l no appetite
l sweating at night
The tuberculosis can be cured by the following six essential drugs.
l Rifampicin (RMP);
The diagnosis of tuberculosis is made on the basis of positive tuberculin test, chest X-rays, positive sputum, gastric analysis, etc. Tuberculosis is not a hereditary disease. The modern treatment of tuberculosis is based on the six main factors : namely rest, diet, drugs, surgery, rehabilitation and health education. BCG vaccine is injected into the skin for providing considerable protection against the tuberculosis disease. BCG-Bacillus Calmette-Guerin.
Origin and Spread
Cholera was originally endemic to the Indian subcontinent, with the Ganges River likely serving as a contamination reservoir. It spread by trade routes (land and sea) to Russia, then to Western Europe, and from Europe to North America. It is now no longer considered an issue in Europe and North America, due to filtering and chlorination of the water supply.
l 1829-1851 – Second pandemic reached Europe, London and Paris in 1832 (in London, it claimed at least 3000 victims according to a 1832 article; in Paris, 20 000 on a population of 650 000, and 100 000 in all of France ), Russia (Cholera Riots), Quebec, Ontario and New York in the same year, and the Pacific coast of North America by 1834.
l 1852-1860 – Third pandemic mainly affected Russia, with over a million deaths.
l 1863-1875 – Fourth pandemic spread mostly in Europe and Africa.
Cholera is an acute infectious, fatal disease and is more common during overcrowded fairs, festivals and after floods. Sometimes cholera occurs in epidemic form (epidemic means wide and destructive in occurrence) spread over large population. Cholera is caused by the bacterium Vibrio cholerae. It is transmitted by flies, contaminated water and food. When sanitation is poor, it spreads rapidly. The incubation period of cholera is generally from a few hours to two or three days. When the bacteria of cholera are ingested, they multiply in the small intestine and invade its epithelial cells. When the bacteria die, they release toxins which irritate the intestinal lining and lead to the secretion of large amounts of water and salts.
Cholera is transmitted through ingestion of feces contaminated with the bacterium. The contamination usually occurs when untreated sewage is released into waterways, affecting the water supply, any foods washed in the water, and shellfish living in the affected waterway—it is rarely spread directly from person to person.
The resulting diarrhea allows the bacterium to spread to other people under unsanitary conditions.
l Watery diarrhoea (i.e., rice-water like stools) which is generally painless.
l Effortless vomiting without nausea.
l Loss of several litres of fluid from patient’s body takes place within hours. The results in dehydration, muscle cramps and weight loss.
l Great loss of mineral salts and body fluid leads to kidney failure.
l Eyes of patient become shrunken.
l Symptoms include those of general GI tract upset: profuse diarrhea (eg 1L/hour), abdominal cramping, fever, nausea and vomiting. Also those of the resulting dehydration: thirst, muscle cramps, weakness, loss of tissue turgor, sunken eyes and wrinkled skin, severe metabolic acidosis with potassium depletion, anuria, circulatory collapse and cyanosis. Death is through circulatory volume shock (massive loss of fluid and electrolytes), and can occur within hours.
l The root causes of these symptoms are the enterotoxins that V. cholerae produces. The main enterotoxin, known as cholera toxin, interacts with G proteins and cyclic AMP in the intestinal lining to open ion channels. As ions flow into the intestinal lumen, water follows through osmosis.
l Persons should be immunized by standard cholera vaccine. One does of immunization lasts for about six months.
l In cholera-prone areas, boiled water and cooked food should be taken.
l Careful personal hygiene and good sanitation in the community are the only certain protection against cholera.
l For preventing dehydration therapy with Oral Rehydration Solution (ORS) should be done immediately. ORS solution contains 3.5 g sodium chloride, 2.5 g sodium bicarbonate, 1.5 g potassium chloride, 20 g glucose, 40 g sucrose in one litre water. Taking small sips of ORS solution contains 3.5 g sodium chloride, 2.5 g sodium bicarbonate, 1.5 g potassium chloride, 20 g glucose, 40 g sucrose in one litre water. Taking small sips of ORS solution at intervals prevents dehydration of the patient.
l Immediate medical advice should be taken.
Salmonella Typhi lives only in humans. Persons with typhoid fever carry the bacteria in their bloodstream and intestinal tract. In addition, a small number of persons, called carriers , recover from typhoid fever but continue to carry the bacteria. Both ill persons and carriers shed S. Typhi in their feces (stool).
You can get typhoid fever if you eat food or drink beverages that have been handled by a person who is shedding S. typhi or if sewage contaminated with S. typhi bacteria gets into the water you use for drinking or washing food. Therefore, typhoid fever is more common in areas of the world where handwashing is less frequent and water is likely to be contaminated with sewage.
Once S. typhi bacteria are eaten or drunk, they multiply and spread into the bloodstream. The body reacts with fever and other signs and symptoms.
Typhoid is most common infectious or communicable disease of India. Typhoid fever is common in humans of the 1 to 15 years age group. Every year about 2.5 million persons suffer from the typhoid. Typhoid is caused by a rod-shaped and motile bacterium, called Salmonella typhi which is commonly found in the intestine of human beings. Human infection is direct.
Infection takes place by the oral route through ingestion of food, milk or water contaminated by contact with faecal matter of the typhoid patient. The bacteria spread through faecal matter by house flies. The symptoms of typhoid often appear 10 to 14 days after the infection.
l Headache and typhoid fever which rises maximum in the afternoon. The temperature increases each day in the first week.
l High fever in the second week. Fever gradually decline during 3rd and 4th day.
l In nutshell symptoms of typhoid include continuous fever often with delirium (disorder of the mind), slow pulse, tender and distended abdomen, diarrhea with water-green stools and eruption of rosy spots (rash) on the body of the patient.
l Proper sanitation and disposal of faecal matter prevents infection.
l TAB-vaccination profices immunity for 3 years. (TAB vaccine contains killed typhoid bacilli and paratyphoid organisms-Salmonella paratyphi A and B).
l Typhoral oral vaccine also prevents typhoid.
l There are standard drugs (e.g., Chloromycetin) which cure typhoid.
Diarrhoeal disease form a group of intestinal infections, including food poisoning. The main symptom of all such infection is diarrhea. Diarrhoea is an abnormally frequent discharge of semisolid or fluid faeces. Other symptoms of diarrhoeal disease include decreased appetite, nausea, vomiting, borborygmus (i.e., gurgling noise produced by movement of gas in the alimentary canal) and abdominal cramps. There may be blood and mucus in the tools. Persistent vomiting and loose stools cause dehydration and shock. Blood pressure may fall, pulse rate increases and temperature rise. Diarrhoea is one of the major causes of infant mortality in India.
Infection of diarrhea spread through contaminated food, water drinks, hands, clothes, bed sheets and utensils. The causative agents of diarrhea are mainly bacteria such as Escherichia coli, Clostridium botulinum, Shigella dysentririae, Campylobacter jejuri and Salmonella. The protozoans (Entamoeba histolytica, Giardia intestinalis and Balantidium coli), some viruses (Rotavirus, Enterovirus, Adenovirus and Norwalk) and nematodes (Ascaris) also act as causative agents of diarrhea.
Toxins released by Escherichia coli cause milk diarrhea to severe dehydration. Shigellosis, caused by Shigella, is characterized by frequent passage of stools with blood and mucus and abdominal cramps. Clostridium botulinum causes food poisoning or botulism from taking preserved foods (dibba-bund food) which have not been properly sterilized before preservation. Such canned food contains the toxin, botulin, released by the bacterium. Botulin is a potent neurotoxin and causes paralysis.
l Frequent loose motions and vomiting lead to dehydration.
l Dehydration (loss of water from body tissues) which makes the patient dangerously ill in a very short time. Most of the infant deaths due to diarrhea can be prevented by making sure that dehydration does not take place due to excessive loss of body fluids through stools and vomiting.
l In cases of dehydration, the patient becomes irritable, eyes appear sunken, nose is pinched and the tongue and the inner side of cheeks appear dry. There is sudden weight loss, weak pulse, deep breathing and fever or fits.
l Eatables should be covered to prevent their contamination.
l Fruits and vegetables should be properly washed before use.
l Proper personal hygiene is important. Hands should be washed with soap and water before eating any food.
l Stale food should not be consumed.
l Community hygiene is also important.
l Complete bed rest should be ensured till the illness is fully controlled.
l For treating diarrhea anti-microbial drugs and anti-diarrhoel agents should be used.
l If there is frequent vomiting, liberal amount of fluids with electrolytes should be provided orally.
l Pulp of boiled unripe banana along with required amount of salt, turmeric powder and lime is helpful in controlling the diarrhea.
l Husk of isabgol seed (Plantago ovata) with water or curd provides relief.
How to prevent dehydration in diarrhea
Dehydration of patient can be countered with oral rehydration therapy, i.e., intake of adequate fluid and electrolytes. Indeed a large number of children can be saved from death by oral rehydration in diarrhea by giving them a mixture of salt, sugar and water through mouth, five to six times a day. An ideal solution, called ORS (Oral Rehydration Solution) to prevent dehydration in child can be prepared as follows : take a glass of water and add to it (i) three teaspoonfuls of sugar; (ii) a quarter teaspoonful of common salt, (iii) a pinch of sodium bicarbonate, and (iv) a few drops of lemon juice. Mix it well and give this solution to the patient (child) having diarrhea at least five to six times a day to prevent dehydration. It should be kept in mind that this solution is made for preventing dehydration and it contains sugar which is a good nutrient for the growth of microorganisms. So, if this solution is kept for a long time then microorganisms will grow in it and it will get spoiled. In this way this ORS will become unfit for the patient (child). So a small quantity of the solution should be prepared fresh each time just before giving it to the patient (child) to prevent further infection. Dilute soaps and dals, rice-water and butter-milk can also be given to the child to compensate the loss of water. Meanwhile, a doctor should be called in who will give some antibiotic treatment. In children, diarrhea can be prevented by keeping clean surroundings, clean milk and feeding bottles and by following proper feeding habits. There is no vaccine for preventing diarrhea.
What is chronic diarrhea
Diarrhea that lasts for more than 2 weeks is considered persistent or chronic. In an otherwise healthy person, chronic diarrhea may be a nuisance problem, or, for someone who has a weak immune system, a life-threatening illness.
Diarrhea caused by an infection may result from:
- Parasites, such as: Cryptosporidium parvum, Cyclospora cayetanensis, Entamoeba histolytica, Giardia lamblia, microsporidia
- Bacteria, such as: Campylobacter, Clostridium difficile, Escherichia coli, Listeria monocytogenes, Salmonella enteritidis, Shigella
Infection of anthrax can occur in following three forms :
l Cutaneous (skin)
l Cutaneous anthrax. About 20% of untreated cases of cutaneous anthrax will result in death. Cutaneous cases are rare.
l Intestinal anthrax. Its symptoms are nausea, loss of appetite, vomiting, pain and vomiting blood. It results in death of 25% to 60% cases.
l Infection by inhalation. Its initial symptoms may resemble a common cold leading to severe breathing problems. It ultimately results in death of patient.
Vaccine of anthrax is found to provide 93% protection against anthrax. Course of four subcutaneous injections of anthrax vaccine is recommended. Mild adverse reaction to the vaccine of anthrax is reported.
At this stage food infection should be distinguished from food poisoning. In food infection, food merely transfers bacteria into the body. In food poisoning, bacteria grow in food and release toxins. When such a food is taken, toxins are absorbed into the blood from the digestive tract. They affect the body quickly, causing gastrointestinal trouble and other effects.
The deficiency diseases are of following three types :
l Protein-Energy deficiency disease or Protein-Energy Malnutrition (PEM);
l Vitamin deficiency;
l Mineral deficiency
Protein-Energy Malnutrition (PEM)
Deficiency of proteins, carbohydrates and fats result’s in protein-calorie malnutrition (PCM) or protein-energy malnutrition (PEM). PEM occurs more frequently among infants and young children between 1 to 5 years of age. It is an important cause of childhood sickliness and mortality. PEM is manifested as failure of body growth both in height and weight. Two common forms of PEM are kwashiorkor and marasmus.
Protein malnutrition, protein-calorie malnutrition; malignant malnutrition;
A form of malnutrition; kwashiorkor is a condition resulting from inadequate protein intake.
Causes, incidence, and risk factors
Kwashiorkor occurs most commonly in areas of famine, limited food supply, and low levels of education leading to inadequate knowledge of diet and feeding techniques.
Early symptoms of any type of malnutrition are very general and include fatigue, irritability, and lethargy. As protein deprivation continues, one sees growth failure, loss of muscle mass, generalized swelling (edema), and decreased immunity. A large, protuberant belly is common. Skin conditions such as dermatitis, changes in pigmentation and thinning of hair are seen frequently. Shock and coma precede death.
Figure 5. 2 A Child suffering from Kwashiorkor
Improving calorie and protein intake will correct kwashiorkor provided that treatment is not started too late. However, full height and growth potential will never be achieved. Severe kwashiorkor, may leave a child with permanent mental and physical disabilities. There is good statistical evidence that malnutrition early in life permanently decreases IQ. Risk factors include living in impoverished countries, countries in political unrest and countries affected by frequent natural disasters such as drought. These conditions are directly or indirectly responsible for scarcity of food, which leads to malnutrition.
Symptoms of kwashiorkor include a swollen abdomen, reddish discoloration of the hair and depigmented skin. The child has a miserable appearance with a “bull-dog” face. Generally, the disease can be treated by adding food energy and protein to the diet; however, mortality can be as high as 60% and it can have a long-term impact on a child’s physical growth and, in severe cases, affect mental development.
l unavailability of adequate food and quality protein
l failure to gain weight and failure of linear growth
l lethargy or apathy
l decreased muscle mass
l large protuberant belly
l changes in skin pigment; may lose pigment where the skin has peeled away(desquamated) and the skin may darken where it has been irritated or traumatized
l hair changes; hair color may change often lightening or becoming reddish. The hair thins and becomes brittle.
l increased numbers of infections and increased severity of normally mild infection as a result of damaged immune system
l shock (late stage)
l coma (late stage)
| It is a severe form of malnutrition caused by inadequate intake of protein and calories, and it usually occurs in the first year of life, resulting in wasting and growth retardation. Marasmus accounts for a large burden on global health. The World Health Organization (WHO) estimates that deaths attributable to marasmus approach 50 percent of the more than ten million deaths of children under age five with PEM.
The major factors that cause a deficit of caloric and protein intake include the following: the transition from breastfeeding to nutrition-poor foods in infancy, acute infections of the gastrointestinal tract, and chronic infections such as HIV or tuberculosis. The imbalance between decreased energy intake and increased energy demands result in a negative energy balance.
|Figure 5. 3 Child suffering from Marasmus|
The physiologic response to a negative energy balance is to reduce energy consumption. Children who suffer from marasmus display decreased activity, lethargy, behavioral changes, slowed growth, and weight loss. The subsequent effects on the body are wasting and a loss of subcutaneous fat and muscle, resulting in growth retardation. The majority of children who suffer from marasmus never return to age-appropriate growth standards.
Marasmus is the predominant form of protein-energy malnutrition in most developing countries. It is associated with the early abandonment or failure of breastfeeding and with consequent infections, most notably those causing infantile gastroenteritis. These infections result from improper hygiene and inadequate knowledge of infant rearing that are prevalent in the rapidly growing slums of developing countries.
Marasmic infants have hunger, gross weight loss, growth retardation, and wasting of subcutaneous fat and muscle. Kwashiorkor is characterized by generalized edema, “flaky paint” dermatosis; thinning, discoloration, and reddening of the hair; enlarged fatty liver; and petulant apathy in addition to retarded growth. Alternating episodes of undernutrition and adequate nutrition may cause the hair to have a dramatic “striped flag” appearance. Almost invariably, infection occurs in all forms of protein-energy malnutrition, with a variety of bacteria producing pneumonia, diarrhea, otitis media, genitourinary disease, and sepsis due to decreased immune response that resembles, in part, acquired immunodeficiency syndrome (AIDS) due to human immunodeficiency virus (HIV) infection.
Deficiency or lack of various minerals in the human diet gives rise to different diseases. Some of the mineral deficiency diseases are : Anaemia, Goitre, Rickets and Osteomalacia.
Anaemia is a disease in which blood is deficient in red blood cells, in haemoglobin or in total volume. It is of following three main types :
(a) Microcytic anaemia
Microcytic anaemia is caused due to deficiency of iron in human diet. It is characterized by reduced number and size of red blood cells (RBCs) and reduced haemoglobin content in RBCs in the body of a person. Since iron element is utilized in the making of haemoglobin, so any deficiency of iron mineral in the diet results in the deficiency of haemoglobin content in red blood cells of our body. The function of haemoglobin is to carry oxygen from lungs to all the body cells and this activity is performed by the help of blood of circulatory system. Since there is not sufficient haemoglobin in the blood of a person suffering from microcytic anaemia, so enough oxygen is not provided to the various body cells of the body to meet their metabolic requirements such as oxidation of food nutrients and production of energy. This blockage of normal metabolic activities of the body cells leads to anaemia. The symptoms of a person suffering from anaemia are as follows :
l looks pale;
l tires easily;
l loses appetite (i.e., anaemic patneit does not feel like eating anything)
l loses weight.
(b) Pernicious anaemia
Pernicious (i.e., highly injurious) anaemia is caused by deficiency of vitamin B12 or cyanocobalamin. It results either due to deficiency of vitamin B12 in the diet or from failure of its absorption from the intestine due to lack of the “intrinsic factor”. Vitamin B12 is essential for the formation and maturation of red blood cells in the bone marrow. So, a deficiency of vitamin B12 in the diet of a person results in the formation of malformed red blood cells i.e., the newly formed RBCs of a patient of pernicious anaemia become large, immature, nucleated and without haemoglobin. Symptoms of perinicious anaemia are pallor (chalkiness) of the skin and mucous membranes, shortness of breath after slight exertion, weakness, loss of weight, fever, etc. It may prove fatal leading to death of the anaemic preson.
(c) Megaloblastic anaemia
Megaloblastic anaemia is caused due to deficiency of folic acid and vitamin B12. It is characterized by the presence of large, immature, nucleated RBCs in large numbers and fewer normal red blood cells.
All types of anaemia can be cured or prevented by eating food-stuffs which are rich in iron, vitamin B12 and folic acid. Meat, liver, green leafy vegetables and germinated pulses are good source of folic acid.
Goitre is an endemic disease which is caused due to deficiency of a mineral, called iodine in human diet. Iodine is an important constituent of a hormone called thyroxine which is secreted by an endocrine gland called thyroid gland. Thyroid gland is situated in the neck region of our body. Thyroxine hormone is a very important hormone. It controls the rate at which food is oxidized in the body (i.e., metabolism)
which in turn regulates the process of growth, development and functions of nervous tissues. If there is less quantity of iodine in the food and water then less amount of thyroxine hormone is produced. So, due to deficiency of iodine, thyroid gland fails to secrete enough thyroxine hormone which disturbs the normal metabolism of the human body. Deficiency of iodine in human diet leads to following abnormalities : (i) retarded growth; (ii) mental disability, and (iii) abnormal enlargement of the thyroid gland (called goitre). In children, deficiency of iodine results in a disease called cretinism or infantile myxedema whose symptoms are abnormal physical growth (physical stunting) and retarded mental growth. Deficiency of dietery iodine in adults leads to a disease is called goitre. The human body requires 150 micrograms of iodine daily otherwise goitre like iodine deficiency disorders (IDD) occur. About 200 million Indians are at the risk of IDD.
Goitre is an abnormal enlargement of the thyroid gland that is commonly visible as a swelling of the anterior part of the neck. In severe iodine deficiency, the body weight increases due to accumulation of fat and retention of water in the body. Occurrence of spontaneous abortion and disorders of nervous system (e.g., 10 per cent drop in IQ of children) also take place in IDD. Goitre is an endemic disease which is more common in hilly areas. For example, in our country many people living in the sub- Himalayan regions from Kashmir to Arunachal Pradesh are suffering from goitre, so, this area is also called goitre belt. In contrast, people living along the sea coast do not suffer from the goitre. What is the reason of such a difference ? The soil of hilly areas is poor in iodine. Due to this the drinking water as well as the food crops grown in hilly areas are deficient in iodine. This deficiency of iodine in the hilly areas, leads to increased goitre cases among hill people. On the other hand, people living along the sea-coast take a large amount of sea-foods such as marine fish, crabs, etc., which contain sufficient iodine. Due to this reason, among coastal people there exists no iodine deficiency, hence, almost no case of goitre.
VITAMIN DEFICIENCY DISEASES
Vitamins are organic compounds, which are always taken alongwith food in small amounts. They are important for certain metabolic activities. Absence of these in diet for prolonged periods may cause deficiency diseases or avitaminosis.
Some of the important diseases caused by the deficiency of vitamins are : Scurvy, Rickets, Beri-beri, Pellagra and Xerophthalmia (dry eye).
Diseases caused by Deficiency of Fat-soluble Vitamins A and D
Xerophthalmia is caused by the deficiency of a fat-soluble vitamin, called vitamin A or retinol. Retinol is a fat-soluble vitamin and is required to maintain general health and vigour of epithelial cells of our eyes, skin and hair and thus, contributes to general growth of our body. Deficiency of vitamin A leads to retarded growth; atrophy; keratinization (keratin deposition) in the epithelial cells; defective tooth formation; increased incidence of infections of ear, respiratory, urinary and digestive organs; dry and
scaly skin (dermatosis); and certain well known eye diseases, such as night blindness, xerophthalmia, and keratomalacia. Thus, the deficiency of vitamin A in the diet causes the skin to become rough and scaly, together with peculiar eruptions on the arms and legs often known as “toad skin” or “shark skin”. Xerophthalmia is a Greek word which means ‘dry eye’. Xerophthalmia is an eye ailment due to the lack of secretion of lacrimal or tear glands. There is an excessive dryness of conjunctiva and cornea, which lose their luster. This may result in bacterial growth, thickening, keratinization and ulceration of cornea and even blindness. Xerophthalmia is the main cause of blindness among children in India. Nearly 35,000 Indian children go blind annually owing to lack of vitamin A. Since vitamin A forms a part of rhodopsin (a deep-red photosensitive pigment of rod cells of eye-retina). So its deficiency results in impairment of dark adaptation of eye or loss of ability of eye cells to adjust to changing intensity of light. Thus, shortage of vitamin A disables a person from seeing in dim light or in dark, a condition called Nyctalopia or night blindness.
Good sources of vitamin A are fish liver oils, liver, egg yolk, milk, cheese and butter. Vitamin A is also produced by our body cells. (i.e., epithelial cells of small intestine and liver cells) from the provitamins such as carotene, a chemical present in green and yellow vegetables and fruits. Such as spinach, methi, cabbage, carrot, tomato, guava, pumpkin, mango and papaya. A provitamin is a vitamin precursor that assumes vitamin activity upon activation or chemical change.
|Deficiency of vitamin D or calciferol in the diet causes increased loss of Ca2+ in urine therefore, no calcium ion (Ca2+) gets deposited in the bone. This causes a disease of bones called rickets in children and osteomalacia in adults. Rickets means twisted and bent bones. Vitamin D prevents rickets by helping the body to absorb calcium. Bones of children suffering from rickets become thin, soft and weak due to poor deposition of calcium and phosphorus in them. In the rickets since the bones of a child remain soft, so, they get deformed or bend easily. The signs of rickets in children are bow legs (bent legs) due to deformation in long bones (leg bones); pigeon type test due to the malformation of chest bones; bending of spine (vertebral column); loss of teeth enamel, teeth enamel becomes thin and show pits; delayed dentition and pain in bones. Since bones of a child suffering from rickets are soft, so they are more susceptible to fracture. Retardation in growth, general muscular weakness and irritability are some other symptoms of rickets.
Rickets is rare where sunshine is plentiful, provided the child’s body is exposed to sunshine. This is because human skin has the power of synthesis of vitamins D under the influence of UV rays of sunlight. In fact, human skin contains a large amount of a compound called 7-dehydrocholesterol. When ultraviolet rays of sunlight falls on our skin, then this compound is converted into vitamins D. In our country the new born babies are exposed to sunlight every day. This is done to produce vitamin D which will prevent rickets. In hospitals, to get UV-rays by artificial means quartz mercury vapour lamps are used to expose new born babies. Since vitamin D can be formed by the action of sunlight on our body, so vitamin D is also called sunshine vitamin. The children are also given codliver oil (which is richest source of vitamin D) to save them from rickets. Diet supplemented with fish, milk and yolk which are rich in vitamin D will either prevent and/or control the disease.
Diseases caused by Deficiency of Water-Soluble Vitamins B and C
Beri-beri is a deficiency disease which is caused due to lack of vitamin B1 or thiamine in the diet.
Thiamine acts as a coenzyme in carbohydrate metabolism and is essential for the synthesis of acetylcholine (a substance involved in transmission of nerve impulses).
Since thiamine promotes the carbohydrate metabolism, it helps in the growth of body. Beri beri is a Sinhalese word which means extreme weakness. The symptoms of vitamin B1 deficiency or beri-beri disease in human beings are the following :
l In beri-beri patients, oedema (swelling) of legs occur due to water-logging of tissues accompanied by pain in legs.
l The patient suffering from beri-beri feels extreme weakness, headache, dizziness, loss of appetite and palpitation. His heart becomes weak and enlarged, which can even lead to heart failure. Paralysis of arms, legs and respiratory muscles also occur in beri-beri patients.
l Decrease in weight, retarded growth, degeneration of nerves and shortness of breath are some other symptoms of beri-beri. Vitamin B1 ultimately leads to mental disturbances or nervous disorders.
Beri-beri disease occurs in those areas where polished rice (dehusked rice) is the major food items (i.e., beri-beri is a endemic disease of estern and southern Asia). This is because polished rice is deficient in vitamin B1. Polished rice is that rice grain from which its thiamine-rich brown outer coat has been removed. This, when rice is polished or dehusked in mills, then its brown coat gets removed and along with this brown coat of rice vitamin B1 content of rice also gets lost. Beri-beri disease was first of all observed among the Japanese sailors who mostly ate polished rice.
Whole wheat bread, ‘Dalia’ and groundnut are very good source of vitamin B1 or thiamine. Other rich sources of thiamine include unpolished rice, whole grain cereals, beans, soyabean, pulses, fruits, green vegetables, sea foods, egg, milk, liver and kidney.
The deficiency of vitamin B4 or niacin (= nicotinic acid) in the diet causes a disease called pellagra. Pellegra is an Italian word which means rough skin. Pellegra disease is characterized by four D’s (called 4D-Syndrome) i.e., four groups of symptoms, each beginning with letter D. These are : Dermatitis, Diarrhoea, Dementia and Death.
l Dermatitis means inflammation of the skin and it is characterized by skin eczema (reddening and drying of skin); soreness of mouth; swelling and redness of the gums and tongue.
l The skin or face, neck, hands, feet, elbow, wrists and knees becomes red and itchy and is peeled off causing pigmentation in patches.
l Diarrhoea means loose motion which is due to disturbances of digestive tract.
Dementia means psychological disturbances or mental degeneration and its symptoms include depression, irritability and delirium. The personality of pellagra patient too changes, sometimes leading to disorientation, hallucinations and delusions.
Pellegra disease is common amongst people living mainly on the diet of maize or sorghum (Jowar). It is so because rich leucine (an amino acid) contents of maize and jowar interfere with the absorption of niacin in the body. Maize itself contains niacin but in a bound unabsorbable form called niacitin. Important sources of niacin are milk, pulses, beans, lean meat, liver, groundnut, germinated pulses and whole cereals. Niacin is also formed in the body from a dietery amino acid called tryptophan which is richly found in milk. Niacin forms a component of coenzymes (NAD and NADP) which are involved in metabolism of carbohydrates, fats and proteins. It is essential for normal functioning of the skin, intestinal tract and the nervous system.
Deficiency of vitamins C (antiscorbiutic acid or ascorbic acid) in the diet causes a deficiency disease, called scurvy. Vitamin C deficient persons usually include the homeless, alcoholic, lonely house bound women and bottle fed babies. Vitamin C promotes collagen (= protein) synthesis and collagen is a main component of connective tissues which are present in the walls of blood vessels. So due to deficiency of vitamin C, the blood vessels of scurvy patient become fragile due to defective collagen fibres in their walls. This causes bleeding in mucous membrane, gums and joints and under the skin. Symptoms of scurvy or vitamin C deficiency are sore gums that become spongy, swollen and bleedy loose teeth, skin eruptions, frequent nose-bleeding (haemorrhage), anaemia, decline in weight (emaciation), great weakness, and pain in joints. Scarcity of vitamin C also causes loss of appetite, delay in healing of wounds and likelihood of infections. In fact, large dosage of vitamin C help in combating common cold and certain viral infections.
Amla (Indian gooseberries) and pineapple, grapes all the citrus fruits such as lime, lemon, and oranges are good sources of vitamin C or anti-scurvy vitamin. Amla is one of the richest natural source of vitamin C. Guava is another rich source of vitamin C. Uncooked green vegetables such as cabbage and cauliflower and tomatoes also contain great amount of vitamin C. Milk does not contain vitamin C. Vitamin C is a water soluble vitamin, so, when cut green vegetables are washed repeatedly, it is depleted from them. Further, vitamin C is comparatively unstable and it is destroyed by heat. So the practice is prolonged cooking in open vessels tends to destroy vitamin C.
Scurvy is treated with large doses of vitamin C tablets, but once the deficiency has been corrected continuing supply of vitamin C should be ensured.
A recent report from Italy shows that women between the ages of 17 and 25 have a very high rate of infections with sexually acquired viruses that are suspected of causing cancer.
The opening to the uterus in the back of the vagina is called the cervix. Doctors used a test called polymerase chain reaction to look for viruses in the cervix and they found a very high incidence of three: the human wart virus, the Epstein-Barr virus that causes mononucleosis and the cytomegalo virus that cause a more severe type of mononucleosis. Virtually all cases of cancer of the cervix are caused by the sexually transmitted human wart virus and the other two are associated with cancers in other parts of the body. In the study, 23% of women under 26 years of age were infected with the human wart virus, 21% with Cytomegalovirus and 19% had epstein-Barr virus. These women had a 16% incidence of two or more infections. On the other hand, women older than 25 had a much lower incidence of infection with the wart and cytomegalo viruses, but had a continuing high incidence of Epstein-Barr virus.
Doctors can prevent cervical cancer by doing yearly Pap smears on all women and removing the precancerous cells before they become cancerous. Almost 50% of women with several partners are infected with the human wart virus. Although more than 92% of all people in North American will develop mononucleosis caused by the Epstein-Barr virus, a much smaller percentage of women have this virus in their cervices.
Very Short Answer Questions
- What is the Pandemic?
- Who discovered the Malarial Parasite – Plasmodium.
- Write the expanded form CDRI.
- Name the virus which causes AIDS.
- From which state of India, the first case of AIDS was reported.
Short Answer Questions
- Write the symptoms of Jaundice.
- How is tuberculosis fatal?
- How is cholera transmitted?
- What are the symptoms of diarrhea?
- Write five symptoms of hepatitis.
Long Answer Questions
- Differentiate between kwashiorkor and marasmus.
- Explain the causes and symptoms of AIDS.
- Name the causative of organism, symptoms of typhoid and its control.
- Explain how cholera proves to be a fatal disease, if not taken care of.
- Describe the deficiency symptoms of Vitamin A, C, D, E and K.