Mosquito’s salivary glands get infected 8 – 10 days after initial infection
infection with one virus type usually gives lifelong immunity to that type, but only short-term immunity to the others. Subsequent infection with a different type increases the risk of severe complications.
Fever caused by the immune response of the bodyA tourniquet test - A blood pressure cuff is applied and inflated to a point between the systolic and diastolic blood pressures for five minutes. The test is positive if there are 10 or more petechiae per square inch.
In as little as 6 generations (two months under ideal conditions) mosquitoes can build up immunity to a pesticide. If you rely on pesticide sprays and foggers, you will need more and more of them to do the job, and you will have to use them more and more often. The best way to make pesticides effective is to minimize their use. Make them your last choice, not your first choice.
Dengue Fever <br />Ahmed Siyah<br />Maldivian Red Crescent<br />
The Agent<br /><ul><li> Breed well in tropical climates
Locate bloodhosts by scent, sight and heat. They can smell your scent, especially the carbon dioxide you exhale 100 feet away (30 meters) and see you at 30 feet (10 meters).</li></li></ul><li>Aedesaegypti<br /><ul><li> Small in size with white dots
Bites during day time, especially at dawn and dusk
Prefers to lay its eggs in artificial water containers, and does not fly far from breeding sites
One female mosquito may lay 100 to 300 eggs at a time and may average 1,000 to 3,000 offspring during her life span.
The dengue virus has no detrimental effect on the mosquito, which remains infected for life, thereby spreading the virus.</li></li></ul><li>The Disease – Dengue Fever<br />Dengue is endemic in more than 110 countries<br />Dengue fever is caused by a virus transmitted from person to person by mosquito during blood meal<br />The incubation period (time between exposure and onset of symptoms) ranges from 3–14 days, but most often it is 4–7 days.<br />The virus has four different types<br />
Dengue Fever contd...<br />Can be transmitted via infected blood products and through organ donation. Vertical transmission (from mother to child) during pregnancy or at birth has been reported.<br />80% people infected with dengue virus are asymptomatic or only have mild symptoms such as an uncomplicated fever<br />Severe disease is more common in babies and young children, and it is more common in children that are relatively well nourished<br />
Symptoms of Dengue Fever<br />Sudden-onset high grade fever (over 40 °C)<br />Headache (typically located behind the eyes)<br />Muscle and joint pains (break bone fever)<br />Nausea and vomiting<br />Rash<br />Mild bleeding from mouth (gums) and nose<br />Low white blood cell count<br />
Dengue Hemorrhagic Fever<br />Complication of Dengue Fever occur in less than 5% of all cases of dengue.<br />Stomach pains, lethargy, bleeding from mouth and gums <br />Organ damage due to fluid accumulation in chest and abdominal cavity<br />Dysfunction of the bone marrow leads to reduced numbers of platelets<br />
Diagnosis<br />Symptoms are similar to viral fevers<br />Serological tests are expensive and time consuming<br />Diagnosis is mainly by history and clinical examination<br />DHF diagnosed by dropping platelet counts<br />
Treatment<br />No specific treatment. No vaccine.<br />Fever usually runs it’s natural course and subsides<br />Oral rehydration therapy at home with close follow-up<br />Intravenous fluids at hospital <br />Paracetamol for fever and discomfort<br />Blood transfusion to replenish platelets<br />Aspirin SHOULD NOT be given<br />
Prevention – integrated approach<br />WHO recommends an Integrated Vector Control program consisting of five elements: <br />(1) Advocacy, social mobilization and legislation to ensure that public health bodies and communities are strengthened, <br />(2) collaboration between the health and other sectors (public and private), <br />(3) an integrated approach to disease control to maximize use of resources, <br />(4) evidence-based decision making to ensure any interventions are targeted appropriately and <br />(5) capacity-building to ensure an adequate response to the local situation.<br />
Prevention – Fog Sprays<br />Expensive<br />Effective for only 2 to 4 hours<br />Indiscriminate - they kill every insect, even butterflies<br />Mosquitoes that survive come back stronger than ever<br />Does not involve the community in taking responsibility for prevention<br />
Actions<br />Prevent mosquito bites<br />Wear long sleeved clothes<br />Use mosquito repellants<br />Close house doors and windows at dawn and dusk<br />Take extra care to protect people already having dengue fever from mosquitoes<br />Do not send children with viral fever to schools or other classes as it might infect other children<br />Eliminate mosquito breeding places<br />Change water in plant pots every 2 – 3 days<br />Put fish into wells and other water containers<br />Upend any container that can collect water<br />Dispose of rubbish that can collect water<br />Cover water containers<br />