Dengue Fever

Tourniquet test is used in diagnosis of dengue haemorrhagic syndrome (DHS).

The test is performed using a blood pressure cuff which is inflated to a point midway between the systolic and the diastolic blood pressure for 5 minutes.

In DHS, test usually gives a positive result, i.e more than 20 petechiae per 2.5 square cm.

Ref: Park 21st edition, page: 227.

Group A arbovirus include:

Dengue hemorrhagic fever, a rare complication of dengue fever, characterized by high fever, damage to lymph and blood vessels, bleeding from the nose and gums, enlargement of the liver, and failure of the circulatory system.

The symptoms may progress to massive bleeding, shock, and death.

This is called dengue shock syndrome (DSS).

Here plasma volume replacement is most urgent, IV crystalloids are used for that purpose.

Epistaxis and scattered petechiae are often noted in uncomplicated dengue.

Ref: Harrisons Principles of Internal Medicine, 18th Edition, Page 1621

Ans. is ‘a’ i.e., Dengue virus 

• Dengue virus (a member of flavivirodae) is an enveloped virus.
• Adenovirus, norwalk virus (calciviridae) and hepatitis A virus (Picornaviridae) are non-enveloped viruses.

Ans. is ‘a’ i.e., Dengue fever

Ans. is ‘b’ i.e., 2

“Dengue type-2 strain is being considered to be more virulent strain”.

Ans. is ‘c’ i.e., Neutralization test

DIAGNOSIS OF DENGUE FEVER

.The diagnosis of dengue fever can be made by ‑

A)   Clinical diagnosis

B) Laboratory diagnosis

Ans. is ‘b’ i.e., Typhus; ‘c’ i.e., Dengue

Ans. is ‘c’ i.e., KFD 

o KFD is transmitted by hard tick where as all else are transmitted by mosquitoes.

Ans. is `b’ i.e., Eggs cannot survive more than 1 week without water 

o In case of aedes agegyti, moisture is a limiting factor for egg survival with surival at higher humidities and eggs

may hatch even after 16 weeks at higher humidities

About other options

o The female aedes arc fearless biters, and they bite chiefly during the day.

o They bite repeatedly to have 1-3 blood meals.

o Aedes transmits dengue fever.

o Aedes prefer artificial collection of water (stagnant water)

Ans. D i.e. Dengue fever

Ans. B i.e. Dengue

Ans. C: Dengue

Aedes mosquito spread the following disease:

1. Chikungunya fever
2. Yellow fever (Not in India)
3. Dengue fever
4. Dengue hemorrhagic fever
5. Filaria (Not in India)
6. Rift valley fever

Japanese encephalitis is caused by culex mosquito.

Ans. C: Falling hematocrit value

Dengue infection can affect many organs and thus may present unusually as liver dysfunction, renal impairment, meningo­encephalitis or gastroenteritis.

• Fever, headaches, eye pain, severe dizziness and loss of appetite.
• Hemorrhagic tendency (positive tourniquet test, spontaneous bruising, bleeding from mucosa, gingiva, injection sites, etc.; vomiting blood, or bloody diarrhoea)
• Thrombocytopenia (<100,000 platelets per mm³ or estimated as less than 3 platelets per high power field)
• Evidence of plasma leakage (Hematocrit more than 20% higher than expected, or drop in hematocrit of 20% or more from baseline following IV fluid, pleural effusion, ascites, hypoproteinemia)
• Encephalitic occurrences

Ans: B i.e. Thrombosis

Dengue hemorrhagic fever

In mild forms of dengue hemorrhagic fever, there is thrombocytopenia and haemoconcentration

Minor (petechiae, ecchymoses, epistaxis) or major (gastrointestinal or cerebrovascular) haemorrhagic signs may occur in dengue hemorrhagic fever

• Acute onset presents with fever, backache, arthralgias, generalized pains (break bone fever), relative bradycardia, lymphadenopathy etc.

Ans. D: Hepato-splenomegaly

Dengue starts with chills, headache, pain upon moving the eyes, and low backache. Painful aching in the legs and joints occurs during the first hours of illness (breakbone fever).

The temperature rises quickly as high as 104° F (40° C), with relative low heart rate and low blood pressure.

The eyes become reddened. A flushing or pale pink rash comes over the face and then disappears.

Fever and other signs of dengue last for two to four days, followed by rapid drop in temperature (defervescence) with profuse sweating. This precedes a period with normal temperature and a sense of well-being that lasts about a day. A second rapid rise in temperature follows. A characteristic rash appears along with the fever and spreads from the extremities to cover the entire body except the face.

Dengue hemorrhagic fever (DHF) is identified by the detection of bleeding tendencies. Hepatomegaly may be present in more severe frank cases of DHF

Ans. is ‘b’ i.e., NS-1 antigen detection

Ans. is `d’ i.e., Infection with more than one dengue virus

DENGUE FEVER

• Dengue fever is caused by arboviruses (at least 4 serotypes have been recognized)
• It is transmitted by Aedes (Aedes aegypti is the main vector).
• The reservoir of infection is both man and mosquito.
• The transmission cycle is Man-mosquito-man
• Dengue fever occurs both epidemically and endemically. Epidemics starts in rainy season and are usually explosive.
• Aedes mosquito becomes infective by feeding on a patient from the day before onset to the 5^th day of illness.

Ans:B.)Eggs cannot survive more than 1 week without water.

The vector shown in the photograph above represents aedes mosquito.

In case of aedes agegyti, moisture is a limiting factor for egg survival with surival at higher humidities and eggs may hatch even after 16 weeks at higher humidities.

About other options

o The female aedes arc fearless biters, and they bite chiefly during the day.

o They bite repeatedly to have 1-3 blood meals.

o Aedes transmits dengue fever.

o Aedes prefer artificial collection of water (stagnant water).

Ans:C.)Dengue.

The vector shown in the photograph above represents aedes mosquitoe.

Aedes mosquito

• Aedes mosquitoes are visually distinctive because they have noticeable black and white markings on their body and legs.
• Unlike most other mosquitoes, they are active and bite only during the daytime.
• They breed in clear,stagnant water.
• In case of aedes agegyti, moisture is a limiting factor for egg survival with surival at higher humidities and eggs may hatch even after 16 weeks at higher humidities.
• Aedes mosquito spread the following disease:
  • Chikungunya fever
  • Yellow fever (Not in India)
  • Dengue fever
  • Dengue hemorrhagic fever
  • Filaria (Not in India)
  • Rift valley fever

Ans. a. Lamivudine is the drug of choice

Ans. is ‘b’ i.e., Dengue fever

• White disease         AIDS
• Poverty disease → Cholera
• Hundred day cough: Pertussis (Whooping cough)
• 5 day fever: Trench fever
• 8′ day disease: Tetanus
• Black sickness: Kala azar
• Black death: Plague
• Cerebrospinal fever: Meningococcal meningitis
• Breakbone fever: Dengue
• Koch’s phenomenon: Tuberculosis
• Hansen ‘s disease: Leprosy
• Break-bone fever: Dengue
• Slim disease: AIDS
• Monkey fever : KFD
• First disease/ Rubeolla: Measles
• Second disease: Scarlet fever
• Third disease/ German Measles: Rubella
• Fourth disease: Duke’s disease
• Fifth disease: Erythema infectiosum (Parvovirus)
• Sixth disease/ Baby Measles/ 3-day fever: Exanthem subitum/ Roseola infantum
• Barometer of Social Welfare (India): Tuberculosis
• Father of Public Health: Cholera
• River Blindness: Onchocerciasis