Pa Tho Physiology of DENGUE Bite of a Virus Carrying Aedes Mosquito

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Transcript of Pa Tho Physiology of DENGUE Bite of a Virus Carrying Aedes Mosquito

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    Thalassemia

    Thalassemiaalso called Mediterranean anemiais an inherited blood disorder

    characterized by less hemoglobin and fewer red blood cells in your body than normal.

    Defects in the genes that make hemoglobin cause thalassemia. Hemoglobin is the

    substance in red blood cells that allows the cells to carry oxygen from your lungs tothe other parts of your body. Because of low hemoglobin and a low amount of red

    blood cells, thalassemia results in anemia.

    If you have a mild form of thalassemia, you may not require any treatment. But, ifyou

    have a more severe form, you may need blood transfusions on a regular basis.Although in some

    cases severe thalassemia can be life-threatening, milder forms ofthalassemia usually can be

    effectively treated.

    Although thalassemia causes anemia, don't confuse thalassemia with iron deficiency

    anemia. People with thalassemia often have more iron in their bodies than they need.For this reason, if you have thalassemia, don't take iron supplements unless your

    doctor recommends it.

    Symptoms

    Signs and symptoms of thalassemia include:

    Fatigue

    Weakness

    Shortness of breath

    Yellow discoloration of the skin (jaundice)

    Bone deformities in the face

    Slow growth

    Protruding abdomen

    The signs and symptoms you experience depend on your type and severity of

    thalassemia. Some babies show signs and symptoms of thalassemia at birth, whileothers may not develop signs or symptoms until they're about 6 to 12 months old.

    Some people who have only one hemoglobin gene affected don't experience any

    thalassemia symptoms.

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    Causes;

    Blood consists of liquid, called plasma, and three types of cells that float within the

    plasma:

    White blood cells. These blood cells fight infection.

    Platelets. These blood cells help your blood clot after a cut.

    Red blood cells (erythrocytes). These blood cells carry oxygen from your

    lungs, through you

    r bloodstream, to your brain and your body's other organs

    and tissues. Your body needs a supply of oxygenated blood to function.

    Oxygenated blood helps give your body its energy and your skin a healthy

    glow.

    Red blood cells contain hemoglobina red, iron-rich protein that gives blood its red

    color. Hemoglobin enables red blood cells to carry oxygen from your lungs to allparts of your body and to carry carbon dioxide from other parts of your body to your

    lungs so that it can be exhaled. Most blood cells, including red blood cells, are

    produced regularly in your bone marrowa red, spongy material found within the

    cavities of many of your large bones.

    Thalassemia disrupts the normal production of hemoglobin and leads to a low level of

    hemoglobin and a high rate of red blood cell destruction, causing anemia. When

    you're anemic, your blood doesn't have enough red blood cells to carry oxygen to your

    tissuesleaving you fatigued.

    Thalassemia is caused by defects in the genes that make hemoglobin. The only way to

    get thalassemia is to inherit one or more defective hemoglobin genes from your

    parents.

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    There are two types of thalassemia: alpha and beta, named for the two protein chains

    that make up normal hemoglobin. The type of thalassemia you have depends on the

    type of defective gene you inherit.

    Alpha-thalassemia

    Four genes are involved in making the alpha hemoglobin chain. You get two from

    each of your parents. If one or more of the alpha hemoglobin genes are defective, you

    develop alpha-thalassemia.

    The more defective genes you have, the more severe your alpha-thalassemia:

    One gene. If only one of your alpha hemoglobin genes is defective, you'll

    have no signs or symptoms of thalassemia. But, you're a carrier of the disease

    and can pass it on to your children.

    Two genes. If you have two defective alpha hemoglobin genes, thalassemia

    signs and symptoms are mild. This condition is called alpha-thalassemia

    minor.

    Three genes. If three of your alpha hemoglobin genes are defective, your

    signs and symptoms will be moderate to severe. This condition is also called

    hemoglobin H disease.

    Four genes. When all four alpha hemoglobin genes are defective, the

    condition is called alpha-thalassemia major or hydrops fetalis. It usually

    causes a fetus to die before delivery or shortly after birth.

    Beta-thalassemia

    Two genes are involved in making the beta hemoglobin chain. You get one from each

    of your parents. If one or both of the beta hemoglobin genes are defective, you

    develop beta-thalassemia.

    One gene. If one of your beta hemoglobin genes is defective, you have mild

    signs and symptoms. This condition is called beta-thalassemia minor.

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    Two genes. If both of your beta hemoglobin genes are defective, your signs

    and symptoms will be moderate to severe. This condition is called beta-

    thalassemia major or Cooley's anemia. Babies born with two defective beta

    hemoglobin genes usually are healthy at birth, but develop signs and

    symptoms within the first year of life.

    Risk factors

    Factors that increase your risk of thalassemia include:

    Family history. Thalassemia is an inherited disorder, passed from parents to

    children through defective hemoglobin genes.

    Ancestry. Thalassemia occurs most often in people of Italian, Greek, Middle

    Eastern, southern Asian and African ancestry. Alpha-thalassemia affects

    mainly people of Southeast Asian, Chinese and Filipino descent.

    When to seek medical advice

    Make an appointment with your child's health care provider for an evaluation if he or

    she has any of the following signs or symptoms of thalassemia:

    Fatigue

    Weakness

    Shortness of breath

    Yellow discoloration of the skin (jaundice)

    Bone deformities in the face

    Slow growth

    Protruding abdomen

    Dark urine

    Tests and diagnosis

    Most children who have moderate to severe cases of thalassemia show signs and

    symptoms within their first two years of life. If your doctor suspects your child has

    thalassemia, he or she may confirm a diagnosis using blood tests. If your child has

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    thalassemia, blood tests may reveal a low level of red blood cells. The red blood cells

    may be smaller than normal, pale (a sign of low hemoglobin), varied in size and

    shape, and have uneven hemoglobin distributiongiving the cells a bull's-eye

    appearance under the microscope.

    Blood tests may also be used to measure the amount of iron in your child's blood andto evaluatehis or her hemoglobin. In some cases, a blood test may be used for DNAanalysis to diagnose

    thalassemia or to determine if a person is carrying defective

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    Dengue hemorrhagic fever

    Dengue, the most common arboviral illness transmitted worldwide, is caused by infection

    with 1 of the 4 serotypes of dengue virus, family Flaviviridae, genus Flavivirus (single-stranded

    no segmented RNA viruses). Dengue is transmitted by mosquitoes of the genusAedes, which are

    widely distributed in subtropical and tropical areas of the world, and is classified as a major

    global health threat by the World Health Organization (WHO)

    Dengue is a mosquito-borne infection that in recent decades

    has become a major international public health concern. Dengue is found in tropical and sub-

    tropical regions around the world, predominantly in urban and semi-urban areas. Dengue

    hemorrhagic fever (DHF), a potentially lethal complication, was first recognized in the 1950s

    during dengue epidemics in the Philippines and Thailand. Today DHF affects most Asian

    countries and has become a leading cause of hospitalization and death among children in the

    region. There are four distinct, but closely related, viruses that cause dengue. Recovery from

    infection by one provides lifelong immunity against that virus but confers only partial and

    transient protection against subsequent infection by the other three viruses. There is good

    evidence that sequential infection increases the risk of developing DHF.

    Global burden of dengue

    The incidence of dengue has grown dramatically around the world in recent decades.

    Some 2.5 billion peopletwo fifths of the world's populationare now at risk from dengue.

    WHO currently estimates there may be 50 million dengue infections worldwide every year. In2007 alone, there were more than 890 000 reported cases of dengue in the Americas, of which 26

    000 cases were DHF. The disease is now endemic in more than 100 countries in Africa, the

    Americas, the Eastern Mediterranean, South-east Asia and the Western Pacific. South-east Asia

    and the. Western Pacific is the most seriously affected. Before 1970 only nine countries had

    experienced DHF epidemics, a number that had increased more than four-fold by 1995.Not only

    is the number of cases increa