Systemic Infections (Dengue & Leptospirosis)

• Systemic Infections


  • Dengue Fever
  • Rickettsial Infections
  • Leptospirosis
• Dengue Fever


  Viral infection transmitted by Aedes mosquito

  
• Dengue Virus Types


  • Dengue 1
  • Dengue 2
  • Dengue 3
  • Dengue 4
• Aedes Mosquito


  • Fine white spots at the base of wings
  • White bands on legs
  • Day-biting
  • Active 6am to 6pm
  • Limited, low flying movement
  • Habitat - stagnant water

  
• Mode of Transmission


  Bite of Aedes mosquito
• Dengue Fever Classification


  • Grade 1: Fever, non-specific symptoms, malaise, hemorrhagic manifestation, positive tourniquet test
  • Grade 2: Grade 1 signs, spontaneous bleeding from gums, nose and GIT
  • Grade 3: Grade 2 plus circulatory failure, weak pulse, narrow pulse pressure, hypotension, cold clammy skin, restlessness
  • Grade 4: Grade 3 plus profound shock, undetectable BP and pulse
• Classical Dengue Fever


  • Fever with abrupt onset, subsides and reappears after 2-3 days (camel-back or saddle-back pattern)
  • Generalized muscle and bone pain
  • Rash - maculopapular (petechiae) on 3rd-5th day, morbiliform or scarlatiniform over trunk, face and extremities
  • Generalized lymphadenopathy
  • Leucopenia
• Dengue Hemorrhagic Fever


  • Fever for 2-5 days
  • Prostration
  • Restlessness
  • Facial flushing
  • Abdominal pain
  • Dehydration
  • Bleeding - petechiae, epistaxis, hematemesis or melena, purpura or ecchymosis
  • Hepatomegaly, development of hepatitis
• Dengue Shock Syndrome (DSS)

  • Bleeding or third space continues
  • Rapid and weak pulse
  • Narrow pulse pressure (</= 20 mmHg)
  • Cold extremities and tachycardia
  • Decreased or absent urine
  • Restlessness
• DOH Definition of Dengue

  • Fever
  • Hemorrhage
  • Thrombocytopenia (platelet count < 100,000/mm3)
  • Hemoconcentration (increase in hematocrit)
• Dengue Diagnostic Procedures


  • Dengue Rapid test
  • Tourniquet Test or Rumple-Leede Test
  • Platelet count
  • Clinical manifestations
  • Serology
  • Immuno-PCR (detects viral nucleic acid and antigen)
• Dengue Prevention


  • Vaccine
  • Mass education
  • Active surveillance
  • Mosquito control - larval source reduction
  • Prevent mosquito bite - mosquito nets, screen window, anti mosquito lotions
  • Fogging (not effective)

  
• Leptospirosis


  Bacterial infection caused by Leptospira interrogans (spirochete)
• Leptospirosis Reservoir


  • Rats
  • Rodents
  • Household pets
  • Livestock
• Source of Leptospirosis Infection

  • Urine of animals
  • Contaminated soil and water
• Leptospirosis Mode of Transmission


  • Break in skin / mucous membrane by wading or swimming in contaminated water
  • Ingestion of contaminated water or food
• Leptospirosis At-Risk Groups


  • Sewage workers
  • Farmers
  • Miners
• Leptospirosis Clinical Manifestations


  • Biphasic infection
  • Initial: fever, severe headache, chills then recede for a short period
  • Followed by immune period
  • Weil's disease or Infective jaundice in severe cases
  • Meningitis associated with impaired renal function and liver damage
• Leptospirosis Laboratory Diagnosis


  Confirmed by increase in serum level of agglutinating antibodies
• Leptospirosis Treatment


  • Drug of choice: Doxycycline
  • Prophylaxis (post-exposure): Doxycycline
• Leptospirosis Prevention


  • Avoid wading in contaminated water
  • Avoid contact with contaminated soil