Grade 12 Zoology Note

Communicable and Non-communicable diseases

Communicable diseases


It is one of the communicable disease and commonly called Enteric fever or Salient fever.


At the beginning slow fever follow higher fever, headache, sweating, chill fever, nausea, gastro intestinal problems, slight abdominal pain, diarrhea, heart beat raises, number of WBCs reduces about 3000 per cubic mm, swelling of liver, spleen, loss of appetite, body weight loss and at the chronic stage blood may comes out in the stool shows ulceration in the intestine etc.

Causative agent:

The main causes of the Enteric fever is due to bacillus called salmonella of enterobacterioceae group. Salmonella constitute species;





Shape and size: cylindrical or thread like, 3-4 µm.

Salmonella in patient blood can be easily identify by culturing blood to 24-48hrs.

Typhoid is also commonly called water borne disease because bacteria transmit very fastly through water media or any other contaminated foods.

Control Measures:

1.Patient must be isolate from other family members.

2.Patient belongings should sterilized well the direct sunlight for 4-6hrs.

3.Patient belongings can be treat by 1% phenol solution or dettol solution.

4.Patient urination and solid waste should be disposed scientifically.

5.Live in most hygienic way is the best control method.


The conformed typhoid should be checked by physician and medicines are given according to the advised of physician.


b.antibiotics as ciprofloxacin



Commonly called as warm disease or pet disease of South asian countries specially India, Nepal, Bangladesh, etc.


In the children: very acute in children, expose gastro- intestinal disorders, severe abdominal pain, continous crying habit, eye balls looks like xeropthalmia, belly protrude out, nausea, vomiting, diarrhea, coughing, excessive growth of parasites may comes out from the mouth during vomiting, body weight loss, loss of appetite.

In adult: Disease is mild, expose slight pain in the abdomen, chances of pharyngitis, laryngitis, nausea, loss of appeitite,etc.

Causative agent:

Caused by endoparasites Ascaris lumbricoides commonly called roundworm.

 Shape: body is long, cylindrical, unsegmented, colourless, sexes are separated ,etc.

Male: short with posterior end cured have a pair of pineal seta as copulatory organs and female is long, both ends straight, complete life cycle in 2 or more hosts. Its Juvenile stage is the main which reaches the blood vessels of brain may cause brain cyst.

Site or location: Intestine, Ileum and colon

Control Measures:

1.Live in most hygienic way.

2.Scientific disposal of solid wastes.

3.Sterilization of foods before feeding.

4.Nails of the children must be cut.

5.Education about impact of the disease should be known to common people, etc.


For children: antiwar syrup of Albendazole or Hebendazole.

For adult: tabs of Albendazole, Mebendazole, Piperizine.


Tuberclosis (T.B) is one of the very common communicating diseases, especially in village areas. It is said that more people died of T.B then other diseases in Nepal. Before 1960s T.B is the most dangerous diseases because of unknown treatment. From 1960-1970 yrs. Are called golden year of diseases, because most of the treatment of the diseases were discovered.

Symptoms of the disease:

Based upon the symptoms T.B is categorized in to two types.

1.Pulmonary T.B:

Gradually low fever raises to 105-106o F, increases in the chest pain, continuous coughing, body weight drastically looses, patient body looks skinless, appearances of fine holes in the lungs and at the coma, heart beat increases, pulse rate increases, fresh blood releases continuously in the sputum finally dies.

2.Extra pulmonary T.B:

a.Skin T.B: Change the colouration of skin wrinkling skin, skin damages etc.

b.Muscular T.B: Frequent muscular cramps, muscles damages due to tuber cluing chemical secreted by the agent.

c.Blood T.B: Fever ups and downs, no. of RBCs Reduces, lead anaemia, etc.

d.Abdominal T.B: Undigestion, gastro intestinal problem, stomach pain etc 

e.Brain T.B: loss of memory, Thinking dullness, body lethargy.

f.Bone T.B: low production of RBCs and WBCs, slow fracture heal up, etc.

Causative agent:

The main cause of T.B is due to Bacillus tubercle commonly known as Mycobacterium tuberculosis of the enterobacteacea group. It is common in man but in other domestic animals infected by M.bovis.

Modes of infection:

T.B is highly infectious diseases which can easily transmitted through any infective media such as infected food materials, vegetables, water, milk, patients belonging infected sputum, etc.

Incubation period:

Depending upon the site of infection incubation period of the bacteria changes, the average time period is about 4-6 weeks.

Control measures:

1.Due to infectious diseases, patient should be keep in isolation.

2.The belongings of the patient should be sterilized well.

3.Disease can be conform by skin inflammatory test.

4.Patient should keep in rehabilitation or completely in rest.

5.Patient should take BCG vaccine.                                                     


T.B can be cured completely either in primary stage or in secondary stage. If the patient is in primary stage, medicines are given at least for 9 months and in secondary stages medicine should given 18 month regularly on the basis of age, weight of the body.

Major medicines:

Refampsin capsule, Isonex tab., Ethambutol tab, pyraginamide tab, streptomycin injection.etc

AIDS (Acquired Immune Deficiency Syndrome):

It means with the loss of body immunity after the birth whose exact fact and treatment unknown. It is believed that an AIDS disease was transmitted by certain green monkeys found in central Africa. The first AIDS patient was found in Haiti, later in 1981 AIDS patient was identified in loss Angle USA. From European countries and after 1985 reported from Asian countries. In Nepal First AIDS patient was declared in 1988 from Biratnagar quarantine office.

General symptoms shown by the AIDS patient by checking the test in the blood

1.Unexplained long term fever-low or high

2.Unexplained loss of body weight.

3.Change in voice nature.

4.Appearence of glands in the body.

5.Appearence of white or pink spots in around the mouth cavities or in the abdominal region.

6.Maximum dancing night sweating and thirst.

7.Unexplained long term nagging cough.

Symptoms shown by the confirmed AIDS patient called ARC diseases.

Patients enter into ARC when damages T lymphocytes of the blood.

1.Diarrhoea or dysentery.

2.fever low or high frequently.

3.Suceptive to any diseases due to loss of body immunity.

4.Partial body paralysis sometimes whole body paralysis, dull memory, body lethargy, etc.

5.loss of body weight.

Mode of infection:

1.Person having the habit of polysex.

2.Person having the habit of homosex.

3. Person having the habit of drug addiction.

4.Transfusion of infected blood.

5.Use of single needle or operating equipment for several times.

Causative agents: Main causes of AIDS is virus, named as human immune virus(HIV), Human T-lymphocyte virus HTLV, Human lymphodenopathy associated virus HTLAV etc.

Control measures:

1.Stop polysex and homosexual habit.

2.Check the blood before transfusion.

3.Use of sterilized equipments.

4.Give up drug addication.

5.Use condom during sex with unknown person.


Still there are no such drugs yet discovered which can completely cure AIDS. The drug available in the market are only to extend lifespan.

Available Drugs: Azidothymidine(AZT) or Zidovudine, Rebavarium.

 Didonosine(DDS) and Zalcitabine.

Non communicable diseases


Hippocrate was the first who gave the word karkinos or cancer diseases. Later karkinos word change in to carcinomes which means cancer in the epithelial tissue. Cancer is non communicable but most dangerous diseases after AIDS. Cancer is mainly two types;

1.Benign cancer:

It is not dangerous cancer in which cells grows within limited area by connective tissue. At the place of growth may or may not have pain. In this type cell never migrate from one organ to the next. It is not fetal.

2.Malignant cancer :

Malignant cancer is commonly called as true cancer which also called tumor. On the basis of the site, cancer can be classified in to following types;

A.Carcinomas cancer: Cancer in epithelial tissue.

B.Leucomias Cancer: Blood cancer.

C.Sarcomas cancer: Cancer in the bone muscles etc.

D.lymphomas cancer: cancer in the lymph nodes or vessels.


Early symptoms can hardly seen because primary stage of cancer do not exposes serious symptoms. Major symptoms are appears in secondary stages.

The symptoms shown by secondary stage of cancer

a.Blood cancer:

Body temperature raises, swelling of body, body looks pale coloured, Similarly anaemia disease, no of RBCs reduce, etc.

b.Abdominal cancer:

Appearances of malignant tumor, gastro intestinal problem,  nausea, vomiting, dysentery, diarrhea etc.

c.Lungs cancer:

Development of chest pain, coughing, Nagging or dry, development of fine pores in the lungs, lungs alveoli gradually filled with body lymph etc.

d.Brain cancer:

Mental retardness, slow body growth, abnormal size of the head, facial paralysis, check body movement or locomotion, etc.

Causative agent:

Till now, there is no such exact fact which causes cancer in the various organs of the body. There are many factors which causes are;


2.Chewing of tobacco.

3.Physical Irritations or Injuries.


5.Ultraviolet Rays.



Symptoms of cancer;

1.Any thickening or lump in the breast or elsewhere.

2.Any change in a mole or wart.

3.Any wound that does not heal.

4.Unusual bleeding or discharge.

5.Persistant cough or hoarseness.

6.Any change in normal bowel habits.


Cancer can be confirmed on the basis of certain pathological examinations. These include biopsy, microscopic examination of body fluids, Blood studies and x-ray.

Preventive measures:

1.To give up smoking and chewing tobacco as theses increase the changes of cancer.

2.To protect the body from excessive exposure of x-rays, ultra-violet rays, sunlight, etc.

3.To be aware of possible dangerous symptoms mentioned above.

4.To have regular medical checkup after age of forty.


The treatment of cancer varies according to the nature of cancer. The common weapons used to fight cancer are surgery, radiotherapy and chemotherapy.


It is very common disease of Nepal India, Burma, also reported from Srilanka,  Africa, china, S. America and Mediterranean  sea.


It shows visceral Leishmaniasis diseases exposes fever with hills, loss of appetite, anemia, Leucopenia, swelling of spleen.

Causative agents:

It is caused by protozoan endemic blood pathogenic parasite called Leishmania sps.

Control measure:

1.Destroy the habitats of sandfly.

2.Regular clean of pet domestic animals.

3.Sterilization of foods. about diseases.


Aminosidine and Ambisone tab., Malifosine.


There is no exact causes about hepatitis disease but believed to be either bacterial or viral infection or Damage in the liver cells or due to damage in the blood capillary of the liver.


At the early stage shows, Fluctuation in fever, muscles aches or pain, loss of appetite, nausea, vomiting, jaundice, ill feeling, etc.

Causative agent:

It is caused by viruses like Hepatitis A virus, B virus, C virus, etc.

Control measures:

a.Live in most hygienic way.

b.Stop to go regularly in crowded areas.

c.Take extra care during swimming, drinking and sanitation.


Antiviral medicines or infections are given according to physicians.

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