INFECTIOUS AND NON-INFECTIOUS DISEASE

(Malaria, Sickle Cell Anemia, Cancer, Zika)

AS and A Level Biology Chapter 10

By: Nada

MALARIAINFECTIOUS DISEASE

Highlights• Malaria is a life-threatening disease that’s typically

transmitted through the bite of an infected Anopheles mosquito.

• Malaria is usually found in tropical and subtropical climates where the parasites that cause it live.

• Congenital malaria occurs when a mother with malaria passes on the disease to her baby at birth.

What causes Malaria?• Infected mosquitoes carry the Plasmodium parasite.

When this mosquito bites you, the parasite is released into your bloodstream.

• Malaria is transmitted by blood, so it can also be transmitted through:

1) An organ transplant2) A transfusion3) Use of shared needles or syringes

Symptoms of MalariaCommon symptoms of malaria include:• shaking chills that can range from moderate to severe• high fever• profuse sweating• headache• nausea• vomiting• diarrhea• anemia• muscle pain• convulsions• coma• bloody stools

Complications caused by Malaria

• swelling of the blood vessels of the brain, or cerebral malaria

• an accumulation of fluid in the lungs that causes breathing problems, or pulmonary edema

• organ failure of the kidneys, liver, or spleen• anemia due to the destruction of red blood cells• low blood sugar

Where Malaria strikes• The area with the most cases of malaria is the Sub-

Saharan Africa. It carries 88% of the world’s cases of malaria, and 90% of deaths caused by malaria.

SICKLE CELL ANEMIANON-INFECTIOUS DISEASE (INHERITED)

Highlight• Sickle cell anemia is a serious inherited blood disorder

where the red blood cells, which carry oxygen around the body, develop abnormally.

• Symptoms of anemia include lethargy (a lack of energy), tiredness and breathlessness, particularly after exercise.

Inheritance disease• Anemia is a disease which can be inherited from either

one or both parents down to their children. However, children inheriting the disease does not show any particular symptoms towards the sickness.

• This disease is more common amongst people of African and Mediterranean descendants.

• It is also the most common inherited disease for people in general.

What happens to the cells• Cells in tissues need a steady supply of oxygen to work well.

Normally, hemoglobin in red blood cells takes up oxygen in the lungs and carries it to all the tissues of the body.

• Red blood cells that contain normal hemoglobin are disc shaped. This shape allows the cells to be flexible so that they can move through large and small blood vessels to deliver oxygen.

• Sickle hemoglobin is not like normal hemoglobin. It can form stiff rods within the red cell, changing it into a crescent, sickle shape.

• Sickle-shaped cells are not flexible and can stick to vessel walls, causing a blockage that slows or stops the flow of blood. When this happens, oxygen can’t reach nearby tissues.

Chances on a childWith each pregnancy, two people with sickle cell traits have:

• A 25 percent chance of having an unaffected child with normal hemoglobin

• A 50 percent chance of having a child who also is a carrier• A 25 percent chance of having a child with sickle cell

anemia

Treatment of sickle cell anemia• People suffering from sickle cell anemia will most likely be

recommended to go to a hospital and get treatment. • Hydroxycarbamide (serious cases where the anemia

does not respond to other treatment)• Blood transfusions• Applications of oxygen, pain-killing drugs and IV fluid

treatment

CANCERNON-INFECTIOUS DISEASE

Highlight• Cancer is a group of diseases involving abnormal cell

division and growth with the potential to invade or spread to other parts of the body.

• Possible signs and symptoms include: a new lump, abnormal bleeding, a prolonged cough, unexplained weight loss, and a change in bowel movements among others

Cause• The great majority of cancers, some 90–95% of cases, are due

to environmental factors. The remaining 5–10% are due to inherited genetics.

• Environmental:  Tobacco (25–30%), diet and obesity (30–35%), infections (15–20%), radiations (up to 10%), stress, lack of physical activity, and environmental pollutions.

Inheritance?Usually cancer is not inherited. However, some people are born with an increased risk of cancer because they inherit an altered gene important for cell growth or for repair of damaged DNA.

CureThere are many ways in which cancer is treated. All according to which type of cancer the person if suffering and how severe it is. Some of the most acknowledge ways are:

• Surgery.• Radiation Therapy.• Chemotherapy.• Immunotherapy.• Targeted Therapy.• Hormone Therapy.• Stem Cell Transplant.• Precision Medicine

ZIKAINFECTIOUS DISEASE

Highlight• Zika virus disease is caused by a virus transmitted

by Aedes mosquitoes.• People with Zika virus disease usually have symptoms that can

include mild fever, skin rashes, conjunctivitis, muscle and joint pain, malaise or headache. These symptoms normally last for 2-7 days.

• There is no specific treatment or vaccine currently available.• The best form of prevention is protection against mosquito bites.• The virus is known to circulate in Africa, the Americas, Asia and the

Pacific.

Where it originatedZika virus is an emerging mosquito-borne virus that was first identified in Uganda in 1947 in rhesus monkeys through a monitoring network of sylvatic yellow fever. It was subsequently identified in humans in 1952 in Uganda and the United Republic of Tanzania.

SymptomsThe symptoms to Zika is similar to the symptoms of other mosquito-borne diseases which are: FeverSkin rashesConjunctivitisMuscle and joint painMalaiseHeadacheThese symptoms are usually mild and last for 2-7 days.

CureThere has no definite cure against Zika. However, people are encouraged to reduce contact with mosquito by:

-Using insect repellent regularly-Wearing clothes (preferably light-coloured) that cover as much of the body as possible.-Using physical barriers such as window screens, closed doors and windows; and if needed, additional personal protection, such as sleeping under mosquito nets during the day. -Empty, clean or cover containers regularly that can store water, such as buckets, drums, pots etc.