Human Health and Disease

A disease is a particular abnormal condition, a disorder of a structure or function, that affects part or all of an organism. The study of disease is called pathology which includes the causal study of etiology. Disease is often construed as a medical condition associated with specific symptoms and signs.[1] It may be caused by external factors such as pathogens, or it may be caused by internal dysfunctions particularly of the immune system such as an immunodeficiency, or a hypersensitivity including allergies and autoimmunity.

1. INTRODUCTION Health - It can be defined as a state of complete physical, mental and social well-being. When people are healthy, they are more efficient at work. Health is affected by:– Genetic disorders – heritable defects of parents to offspring. Infections Life style including food and water we take, rest and exercise we give to our bodies, habits that we have or lack etc. Diseases can be broadly grouped into infectious and non-infectious. Diseases which are easily transmitted from one person to another are called infectious diseases. Among non-infectious diseases, cancer is the major cause of death. Drugs and alcohol abuse also affect our health adversely.

2. Common Infectious Diseases in Humans Pathogen - Pathogens are the parasites that enter the human body through various means, then multiply, and interfere with normal vital activities. Bacterial Diseases Bacteria are prokaryotic, unicellular microorganism that are found everywhere. Bacteria are found in the soil, water and air. Bacteria are also found on human skin and in the digestive tract- Bacteria can enter other body systems and cause infections or disease. Bacteria can enter the body through a cut in the skin, the respiratory tract or the digestive tract. Typhoid:- Pathogen − Salmonella typhi Spreads through − Contaminated food and water Site of infection − Small intestine Symptoms − High fever, stomach pain, headache, loss of appetite, constipation, and intestinal perforations in severe cases .

3. 2) Pneumonia:- Pathogens − Streptococcus pneumoniae and Haemophilus influenzae Spreads through − Droplets/aerosols released from infected person, sharing of glasses or utensils. Site of infection − Alveoli (gets filled with fluid, difficulty in breathing). Symptoms − Fever, chills, cough, headache, lips and nails become grey in severe cases.

4. Viral Diseases A Virus is a small particle that contains proteins and heredity material (DNA or RNA), but is not alive. The virus is surrounded by a protein coat, or capsid. A virus particle can not eat, metabolize food and can only reproduce inside a cell. Outside the cell, the virus particle does nothing and remains inactive. Common cold:- Pathogen − Rhino viruses Site of infection − Nose and respiratory passage. Spreads through − Droplets released from coughing or sneezing, or contaminated objects. Symptoms − Nasal congestion and discharge, sore throat, cough, headache, tiredness.

5. SOME COMMON UPCOMING VIRUS DISEAES Ebola Virus Ebola virus  is a very dangerous virus. It causes a  hemorrhagic fever  called  Ebola virus disease . "Hemorrhagic" means that the victim will bleed a lot, inside and outside their body. Humans may spread the virus to other humans through contact with bodily fluids such as blood. Initial symptoms include fever, headache, muscle pain and chills. Later, a person may experience internal bleeding resulting in vomiting or coughing blood. zika Virus Zika virus disease is caused by a virus transmitted primarily by  Aedes mosquitoes . People with Zika virus disease can have symptoms including mild fever, skin rash, conjunctivitis, muscle and joint pain, malaise or headache. These symptoms normally last for 2-7 days. There's no vaccine or specific treatment for the disease.

6. 1) Ringworms:- Pathogens − Genera Microsporum , Trichophyton , and Epidermophyton Spreads through − Towels, clothes, comb (Fungus is acquired from soil) Symptoms − Appearance of dry, scaly lesions on various body parts with intense itching. Fungal Diseases

7. Protozoan Diseases Protozoan's are unicellular or colonial organisms. Many animal-like and fungus-like protests can cause human diseases including African sleeping sickness, malaria and yellow fever. Some protists require an animal intermediate, such as a mosquito, to enter the body. Sometimes protists enter the body through the digestive tract from contaminated food or water. 1) Malaria:- Pathogen −Protozoan Plasmodium vivax . Vector − Female Anopheles mosquito Symptoms −Head aches, muscle pain, high fever. During fever the patient feels chill and shivering. Mode of spread-This disease spreads by the bite of infected Anopheles mosquito. Only the female Anopheles is capable of spreading the disease because it sucks the blood of man.

8. Life Cycle of Plasmodium Plasmodium requires two hosts to complete its life cycle. When female Anopheles mosquito bites a healthy human being, it releases Plasmodium , which lives in its body as sporozoite (infectious form). The parasites multiply (asexual reproduction) in the liver cells and finally burst the liver cells. Sporozoites are released in blood. Parasites enter RBCs and further multiply (asexual reproduction) here and finally burst RBCs also. Bursting of RBCs is accompanied by release of a toxic substance called haemozoin (associated with fever and chills). In the RBCs, only sporozoites change into gametocytes (sexual stage). Gametocytes multiply. When the diseased person is bitten by a female Anopheles mosquito, gametocytes are introduced into the mosquito.

9. Gametocytes fertilize and develop inside the intestine of mosquito to form sporozoites. Sporozoites are stored in the salivary glands of mosquito and are released into the healthy person who is bitten by this mosquito.

10. 2) Amoebiasis:- Pathogen − Entamoeba histolytica Vector − Housefly Site of infection − Large intestine Symptoms − Constipation, abdominal pain, cramps, stools with mucous, and blood clots.

11. Diseases Caused by Worms Ascariasis:- Pathogen − Round worm, Ascaris. Spreads through − Water, vegetables, fruits contaminated by faeces of infected person. Symptoms − Internal bleeding, muscular pain, fever, anemia, blockage of intestinal passage.

12. 2) Elephantiasis (filariasis):- Pathogen- Wuchereria ( W.malayi and W.bancrofti ) Spreads through − Bite of female mosquito vector Symptom − Chronic inflammation of the organs, usually the lymphatic vessels of lower limb. This enlargement of legs gives the disease its name as Elephantiasis.

13. Immunity What is immunity? The ability of body to fight the disease-causing organisms is called immunity. Types of immunity Immunity is of two types − 1) Innate immunity 2) Acquired immunity

14. AIDS   AIDS (Acquired Immuno Deficiency Syndrome) , Caused by HIV (Human Immunodeficiency Virus) [HIV is a retrovirus (RNA virus)]. Transmission of HIV occurs through:- Sexual contact with infected person. Sharing infected needles (as in case of intravenous drug abusers). Transfusion of contaminated blood Infected mother to child through placenta. Time lag between infection and appearance of symptoms − Few months to many years (5-10 years ).

15. How does AIDS infection spread? When HIV virus enters the host cell, the virus enters into macrophages, where RNA replicates and forms viral DNA by the help of enzyme reverse transcriptase. The viral DNA gets incorporated into the host cell’s DNA and directs the infected cells to produce daughter viruses. The macrophages continue to produce virus that enters the helper T-lymphocytes. Thus the number of helper T-lymphocytes progressively decreases in the body and weaken the immune system. Even infections which could be overcome easily start aggravating. Diagnosis of AIDS : − By ELISA (Enzyme Linked Immuno Sorbent Assay). Treatment : − No permanent cure; antiretroviral therapies can prolong the life of patient.

16. Symptoms of AIDS

17. Prevention of AIDS:- Ensuring use of disposable syringes. Screening blood from blood banks. Advocating safe sex. NACO (National AIDS Control Organization) and many NGOs are doing a lot to create awareness among people.

18. Cancer The process of development of cancer is called oncogenic transformation. Cancer cells divide continuously to give rise to mass of cells (tumor). Tumor caused by abnormal and uncontrolled cell division. Tumor are of 2 types − 1.Benign Tumor 2.Malignant Tumor

19. 1) Benign tumor :− Remain confined to their original location and do not spread. 2) Malignant tumor :− Cells divides and invades new locations by getting transported through blood to distant sites. Metastasis :- Property of malignant tumor to invade the distant body parts, thereby initiating formation of new tumors.

20. Causes of cancer:- Carcinogens − Physical, chemical, and biological agents that cause cancer Example - ionizing radiations (X-rays and gamma rays), non-ionizing radiations (UV) Oncogenic (cancer-causing) viruses − They have viral oncogenes (cancer-causing genes). Sometimes normal genes in our body called proto-oncogenes get converted into cellular oncogenes that cause cancer. Diagnosing cancer:- Biopsy − Suspected tissue is cut into thin sections and examined microscopically Radiography- CT scan (computed tomography), and MRI (Magnetic resonance imaging) are techniques of diagnosing cancers. C T Scan − 3-D imaging of internals of an organ is generated by X-rays. MRI Scan − Pathological and physiological changes in a living tissue are detected by using magnetic fields and non-ionizing radiations. Immunological and molecular biological diagnostic techniques can all be used to detect cancers. Identifying certain genes, which make an individual susceptible to cancers, can help to prevent cancers .

21. Treatment of Cancer:- Radiotherapy − Tumor cells are irradiated to death. Also, proper care is taken for protecting surrounding normal tissues. Chemotherapy − Drugs specific for particular tumors are used to kill cancer cells. They have side effects such as hair loss, anemia, etc. Immunotherapy − Biological response modifiers such as α- interferons are used. They activate the immune system of patient and helps in destroying the tumor. Surgical – Cancerous tissues are surgically removed.

22. Symptoms of Cancer:- Weight loss Fever Fatigue Pain Skin color changes Loss of Appetite Nausea

23. Prevention of Cancer:- Don't use tobacco. Eat a healthy diet. Maintain a healthy weight and be physically active. Get regular medical care.

24. Drugs Commonly Abused Drugs:- 1) Opioids (Heroin) 2) Cannabinoids 3) Cocaine 4) Nicotine 5) Drugs Normally Used as Medicines:- Drugs like barbiturates, amphetamines, benzodiazepines, LSD (Lysergic acid diethyl amides) are used as medicines to help patients with mental illness and insomnia. Morphine: It is a pain killer which is used for patients who have undergone surgery, but it is also abused. Alcohol / Drug Abuse:- Alcohol / drug abuse normally starts in Adolescence. Adolescence is the period during which the child becomes matured. It is between 12–18 years of age.

25. Investigation Typhoid:- Prevention -Preventing typhoid is all about avoiding contaminated food and water. Peel all fruit and vegetable skins before eating. Cook all food thoroughly and eat it while it's hot. Treatment -With appropriate antibiotic therapy, there is usually improvement within one to two days and recovery within 7 to 10 days. Vaccination. Age group more prone to Typhoid -It is common in humans of the 1 to 15 years age group. 2) Pneumonia:- Prevention - Proper vaccination. Good hygiene Don't smoke Treatment -With appropriate antibiotic therapy. Age group more prone to Pneumonia -Infants who are 2 years old or younger and people who are 65 years old or older.

26. 3) Common cold:- Prevention - Wash your hands often. Cover your mouth and nose when sneezing or coughing. Treatment - Pain relievers Decongestant nasal sprays Cough syrups Age group more prone to Common cold- It is common in children of the 6 to 10 year old. 4) Ring Worm:- Prevention -   Keep skin and feet clean and dry. Avoid touching pets with bald spots. Items such as clothing, hats, brushes and towels of an infected person should not be shared with others Treatment-   Antifungal creams or ointments Antifungal tablets Age group more prone to Ring Worm- Equally common in all age groups.

27. 5) Malaria:- Prevention -Eradication of vector Keeping the surrounding clean Treatment -With appropriate antibiotic therapy. Vaccination Age group more prone to Malaria- Children under 5 years of age. 6) Amoebiasis:- Prevention -Proper disposal of faecal matter of the patient. Vegetables and fruits when used raw, should be thoroughly washed. Water should be boiled before drinking. Treatment - With appropriate antibiotic therapy. Age group more prone to Amoebiasis- Most commonly affects young adults(ages 18–35 years).

28. 7) Ascariasis:- Prevention - The disposal of human faeces by underground sewer canals is an efficient measure to prevent the spread. Washing of vegetables and fruits before eating help to keep away the eggs of the worm. Treatment - Medications Surgical intervention Age group more prone to Ascariasis -It is most common in children of 10 years old or younger. 8) Elephantiasis (filariasis):- Prevention -Eradication of vector. Treatment - Surgery Diet and activity. Age group more prone to Elephantiasis- It is observed in all age groups from 10 years and above.

29. BIBLIOGRAPHY This project is made by using the analytical data provided by the following reference books and websites:   Wikipedia (Encyclopedia) Google Google Images NCERT Textbook of XII