Evolution is one of the Biology Topics that has been debated and studied for centuries, exploring the process by which species change over time.
Bacterial Infection: Causes, Symptoms, Treatment
Tuberculosis – Symptoms and Causes
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 that 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 the 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.
Symptoms of Tuberculosis:
The patient with tuberculosis feels sick and weak. There is a loss of appetite and weight. Typical fever patterns 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 areas of tuberculosis infection.
1. Lung or Pulmonary T.B.: The person suffers from pulmonary T.B. has a continuous fever, and persistent cough, and produces blood-stained sputum. There is a loss of weight and weakness. 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 an 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.
2. 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.
Prevention of Tuberculosis:
- Vigorous public health measures 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.
- Immunization with BCG or Bacillus-Calmette-Guerin vaccination prevents tuberculosis.
- BCG vaccine contains weakened Tuberculosis bacillus and it is injected into the skin of a person to give immunity for 3 to 5 years.
Control of Tuberculosis:
Tuberculosis can be cured by the following six essential drugs.
- Rifampicin (RMP)
Thus, T.B. can be controlled by the use of antitubercular therapy (ATT).
The diagnosis of tuberculosis is made on the basis of a 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 tuberculosis disease.
Cholera – Symptoms and Causes
Cholera is an acutely 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) and spread over a 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 that irritate the intestinal lining and produce large amounts of water and salts.
Symptoms of Cholera:
- Watery diarrhea (i.e., rice-water-like stools) which is generally painless.
- Effortless vomiting without nausea.
- Loss of several litres of fluid from the patient’s body takes place within hours. This results in dehydration, muscle cramps, and weight loss.
- Great loss of mineral salts and body fluid leads to kidney failure.
- The eyes of the patient become shrunken.
Prevention of Cholera:
- Persons should be immunized with a standard cholera vaccine. One dose of immunization lasts for about six months.
- In cholera-prone areas, boiled water and cooked food should be taken.
- Careful personal hygiene and good sanitation in the community are the only certain protection against cholera.
Control of Cholera:
- 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, and 40 g sucrose in one liter of water. Taking small sips of ORS solution at intervals prevents the dehydration of the patient.
- Immediate medical advice should be sought.
- Antibiotics such as tetracycline kill the bacteria of cholera.
Antibiotics and Interferon
Antibiotics are chemical substances produced by living organisms such as bacteria and fungi, etc., which can kill or stop the growth of some pathogenic (disease-producing) microorganisms such as bacteria and fungi.
Some of the important antibiotics which are used for the treatment of diseases caused by bacteria and fungi:
The treatment of viral infections is more difficult than that of bacterial infections. For each type of viral infection, the human body produces its own antiviral protein, called interferon (IFN). Interferon is released from the infected and dying host cells. On reaching the uninfected cells, IFN makes them resistant to the virus infection. Interferons have been proven to be effective in treating influenza and hepatitis.
Typhoid Fever – Symptoms and Causes
Typhoid is the most common communicable disease in India. Typhoid fever is common in humans of the 1 to 15 years age group. Every year about 2.5 million persons suffer from 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.
Symptoms of Typhoid:
Symptoms of typhoid are the following:
- Headache and typhoid fever which rises maximum in the afternoon. The temperature increases each day in the first week.
- High fever in the second week. Fever gradually declines during the 3rd and 4th days.
- In a nutshell, symptoms of typhoid include continuous fever often with delirium (a 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.
Prevention of Typhoid:
- Proper sanitation and disposal of faecal matter prevent infection.
- TAB vaccination provides immunity for 3 years. (TAB vaccine contains killed typhoid bacilli and paratyphoid organisms-Salmonella paratyphi A and B).
- Typhoral oral vaccine also prevents typhoid.
Control of Typhoid:
There are standard drugs (e.g., Chloromycetin) that cure typhoid.
Diarrhea: Causes, Treatment, and Symptoms
The diarrhoeal disease forms a group of intestinal infections, including food poisoning. The main symptom of all such infections is diarrhea. Diarrhea is an abnormally frequent discharge of semisolid or fluid feces. Other symptoms of diarrhoeal disease include decreased appetite, nausea, vomiting, borborygmus (i.e., gurgling noise produced by the movement of gas in the alimentary canal), and abdominal cramps.
There may be blood and mucus in the stools. Persistent vomiting and loose stools cause dehydration and shock. Blood pressure may fall, pulse rate increase, and temperature rise. Diarrhea is one of the major causes of infant mortality in India.
Diarrhea spreads through infection 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 dysenteries, 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.
Symptoms of Diarrhoea:
- Frequent loose motions and vomiting which lead to dehydration.
- Dehydration (loss of water from body tissues) 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 through stools and vomiting.
- In cases of dehydration, the patient becomes irritable, eyes appear sunken, the nose is pinched and the tongue and the inner side of the cheeks appear dry. There is sudden weight loss, weak pulse, deep breathing, and fever or fits.
Food poisoning by the bacteria Salmonella is called salmonellosis. Bacteria Salmonella is present in sick farm animals. So the infection of bacteria Salmonella which causes food poisoning is contracted from the sick farm animals through their contaminated food products such as milk, eggs, and meat. When bacteria Salmonella grow and multiply rapidly in our intestines, then food poisoning takes place. Common symptoms include chills, fever, nausea, vomiting, diarrhea, and pain in the abdomen.
Toxins released by Escherichia coli cause mild 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 foods contain the toxin, botulin, released by the bacterium. Botulin is a potent neurotoxin and causes paralysis.
Prevention of Diarrhoea:
- Eatables should be covered to prevent contamination.
- Fruits and vegetables should be properly washed before use.
- Proper personal hygiene is important. Hands should be washed with soap and water before eating any food.
- Stale food should not be consumed.
- Community hygiene is also important.
Control of Diarrhoea:
- Complete bed rest should be ensured till the illness is fully controlled.
- For treating diarrhea anti-microbial drugs and anti-diarrhea agents should be used.
- If there is frequent vomiting, a liberal amount of fluids loaded with electrolytes, should be provided orally.
- A pulp of boiled unripe banana along with the required amount of salt, turmeric powder, and lime is helpful in controlling diarrhea.
- The husk of isabgol seed (Plantago ovata) with water or curd provides relief.
- Saline drip may be given intravenously to maintain fluid and electrolytes in the body. Alternatively, oral rehydration solution (ORS) may be given to the patient periodically.
- Dilute soups and dais, rice water and buttermilk can also be given to the child to compensate for the loss of water.
- Meanwhile, a doctor should be called in who can give some antibiotic treatment.
- In children, diarrhea can be prevented by keeping clean surroundings, cleaning milk, and feeding bottles, and by following proper feeding habits.
- There is no vaccine for preventing diarrhea.
Anthrax – Symptoms and Causes
Anthrax is an acute infectious disease caused by a rod-shaped non-motile bacterium called Bacillus anthracis. This disease commonly occurs in wild and domesticated animals such as cattle, sheep, goats, horses, and pigs. However, it can affect humans if they are exposed to infected animals.
Anthrax can spread by eating the under-cooked meat of infected animals. Human beings can also contract the infection from animal products such as bones, wool, hide, and bristles. B. anthracis produces an extra-cellular toxin. Fowls are resistant to anthrax.
Symptoms of Anthrax:
Infection of anthrax can occur in the following three forms:
- Cutaneous (skin)
(i) Cutaneous Anthrax: About 20 percent of untreated cases of cutaneous anthrax will result in death. Cutaneous cases are rare.
(ii) Intestinal Anthrax: Its symptoms are nausea, loss of appetite, vomiting, pain, and vomiting blood. It results in death in 25 percent to 60 percent of cases.
(iii) Infection by Inhalation: Its initial symptoms may resemble a common cold leading to severe breathing problems. It ultimately results in the death of the patient.
Prevention of Anthrax:
The vaccine for anthrax is found to provide 93 percent protection against anthrax. The course of four subcutaneous injections of the anthrax vaccine is recommended. Mild adverse reaction to the vaccine of anthrax is reported.
Control of Anthrax:
Doctors can prescribe effective antibiotics. Treatment should be started early to get good results.
In food infection, food merely transfers bacteria into the body. In food poisoning, bacteria grow in food and release toxins. When such food is taken, toxins are absorbed into the blood from the digestive tract. They affect the body quickly, causing gastrointestinal trouble and other effects.
Stomach (Peptic) Ulcers: Symptoms, Causes, and Treatment
Peptic ulcers are painful bleeding areas within the stomach and the duodenum. They were once considered to be caused by increased gastric acidity due to stress and lifestyle of the afflicted persons. However, Robin Warren (born 1937) a Perth-based Australian pathologist observed in 1984 that areas of peptic ulcers contained many small curved gram-negative bacterium, named Helicobacter pylori.
Barry Marshall (born 1951), a young clinical fellow of Warren succeeded in culturing the bacteria (1985). Marshall and Warren (1985) found that amoxicillin, an antibiotic effective in killing the bacteria could also cure peptic ulcers. The finding helped in changing a once painful chronic and disabling condition into a short-duration treatable disease. For this breakthrough, Marshall and Warren were awarded Nobel Prize for Physiology and Medicine in 2005.