Public Health Vectors and Pests

Aedes Aegyptii

Common Name Yellow fever mosquito
Scientific Name Stegomyia aegypti; Aedes aegypti
Description Medium-sized blackish mosquito, three to four millimetres in length, easily recognized by a silvery-white 'lyre-shaped" pattern of scales on its scutum. Segments 1 to 4 of the hind tarsi possess broad basal white rings, segment 5 is white. The coloration of both sexes is similar. Females are larger than males, and can be distinguished by small palps tipped with silver or white scales
Habitat  
Lifecycle The eggs are deposited on damp surfaces within artificial containers such as cans, jars, urns or rain-water containers. Old car tires provide an excellent larval habitat and an adult resting site. In tropical climates, larvae are also encountered in natural water retaining cavities in tree holes and herbaceous plants. The eggs of Ae. aegypti can resist desiccation for up to 1 year. Eggs hatch when flooded by deoxygenated water.
 
Disease Transmitted Dengue fever, yellow fever
 
Symptoms Yellow fever
  • Yellow fever is a tropical disease that is spread to humans by infected mosquitoes.
  • Many yellow fever infections are mild, but the disease can cause severe, life-threatening illness.
  • Yellow fever is found only in Africa and South America.
  • Yellow fever is preventable by immunization. Travelers to countries with yellow fever should get the yellow fever vaccine.
  • Many yellow fever infections are mild, but the disease can cause severe, life-threatening illness.
  • Symptoms of severe infection are high fever, chills, headache, muscle aches, vomiting, and backache.
  • After a brief recovery period, the infection can lead to shock, bleeding, and kidney and liver failure. Liver failure causes jaundice (yellowing of the skin and the whites of the eyes), hence the name yellow fever.
Symptoms start 3 to 6 days after being bitten by an infected mosquito.

Dengue Fever

  • Dengue fever is a flu-like illness spread by the bite of an infected mosquito. Dengue hemorrhagic fever is a severe, mostly fatal, complication of dengue fever
  • Dengue fever usually starts suddenly with a high fever, rash, severe headache, pain behind the eyes, and muscle and joint pain.
  • The severity of the joint pain has given dengue the name "breakbone fever." Nausea, vomiting, and loss of appetite are common.
  • A rash usually appears 3 to 4 days after the start of the fever. The illness can last up to 10 days, but complete recovery can take as long as a month.
  • Most dengue infections result in relatively mild illness, but some can progress to dengue hemorrhagic fever.
  • In dengue haemorrhagic fever, the blood vessels start to leak and cause bleeding from the nose, mouth, and gums. Bruising can be a sign of bleeding inside the body. Without prompt treatment, the blood vessels can collapse, causing shock (dengue shock syndrome).
  • Dengue hemorrhagic fever is fatal in about 5 percent of cases, mostly among children and young adults.
  • The time between the bite of a mosquito carrying dengue virus and the start of symptoms averages 4 to 6 days, with a range of 3 to 14 days.
  • An infected person cannot spread the infection to other persons but can be a source of dengue virus for mosquitoes for about 6 days.
Prevention Empty flowerpots, properly maintaining swimming pools, and removing unused tires, can greatly reduce the number of places mosquitoes have to lay eggs. Aerate birdbaths and make sure gutters are free of blockages. Clean pet bowls everyday and always empty overflow dishes for potted plants.
 
Control Mosquito repellents
Use of Mosquito nets
Long sleeved clothing, especially after dusk
Mosquito sprays (insecticide).
 

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