Dengue has become a global problem since the Second World War and is common in more than 110 countries, mainly in Asia and South America. Each year between 50 and 528 million people are infected and approximately 10,000 to 20,000 die. The earliest descriptions of an outbreak date from 1779. Its viral cause and spread were understood by the early 20th century. Apart from eliminating the mosquitos, work is ongoing for medication targeted directly at the virus. It is classified as a neglected tropical disease.

1. Review on “Dengue”
Reviewed by:
Zubayar Rahman
Department of Pharmacy
University of Asia Pacific

2. Introduction:
Dengue is a mosquito-borne viral disease that has rapidly spread in all regions of
WHO in recent years. Dengue virus is transmitted by female mosquitoes mainly of
the species Aedes aegypti and, to a lesser extent, Ae. albopictus. This mosquito
also transmits chikungunya, yellow fever and Zika infection. Dengue is widespread
throughout the tropics, with local variations in risk influenced by rainfall,
temperature and unplanned rapid urbanization.
Severe dengue was first recognized in the 1950s during dengue epidemics in the
Philippines and Thailand. Today, severe dengue affects most Asian and Latin
American countries and has become a leading cause of hospitalization and death
among children and adults in these regions.
Dengue is caused by a virus of the Flaviviridae family and there are 4 distinct, but
closely related, serotypes of the virus that cause dengue (DEN-1, DEN-2, DEN-3
and DEN-4). Recovery from infection by one provides lifelong immunity against
that particular serotype. However, cross-immunity to the other serotypes after
recovery is only partial and temporary. Subsequent infections (secondary infection)
by other serotypes increase the risk of developing severe dengue.
Sign and symptoms of dengue:
Symptoms, which usually begin four to six days after infection and last for up to 10
days, may include
• Sudden, high fever
• Severe headaches
• Pain behind the eyes

3. • Severe joint and muscle pain
• Fatigue
• Nausea
• Vomiting
• Skin rash, which appears two to five days after the onset of fever
• Mild bleeding (such a nose bleed, bleeding gums, or easy bruising)
Sometimes, symptoms are mild and can be mistaken for those of the flu or another
viral infection.
Diagnosis of dengue:
The diagnosis of dengue is usually made clinically. The classic picture is high fever
with no localizing source of infection, a petechial rash with thrombocytopenia and
relative leukopenia (low platelet and white blood cell count). Care has to be taken as
diagnosis of Dengue Hemorrhagic Fever (DHF) can mask end stage liver disease
and vice versa. If one has persistent fever for more than 2 days then one should go
for a complete blood checkup (CBC). If the platelet count and WBC count are below
than their usual range one should go for Dengue Antigen test:
❖ Total White Blood Cells Count: In case of dengue, this test will reveal
leukopenia. The presence of leukocytosis and neutrophilia excludes the
possibility of dengue and bacterial infections (leptospirosis,
meningoencephalitis, septicemic, pyelonephritis etc.) must be considered.
❖ Thrombocytopenia (less than 100.000 per mm3): Total platelets count must
be obtained in every patient with symptoms suggestive of dengue for three or
more days of presentation. Leptospirosis, measles, rubella, meningococcemia
and septicemy may also course with thrombocytopenia.

4. ❖ Hematocrit (micro-hematocrit): According to the definition of DHF, it’s
necessary the presence of hemoconcentration (hematocrit elevated by more
than 20%); when it’s not possible to know the previous value of hematocrit,
we must regard as significantly elevated the results more than 45%.
Treatment of dengue:
Dengue is a virus, so there is no specific treatment or cure. However, intervention
can help, depending on how severe the disease is.
For milder forms, treatment includes:
Preventing dehydration: A high fever and vomiting can dehydrate the body. The
person should drink clean water, ideally bottled rather than tap water. Rehydration
salts can also help replace fluids and minerals.
Painkillers, such as Tylenol or paracetamol: These can help lower fever and ease
pain.
NSAIDs should avoid: Non-steroidal anti-inflammatory drugs (NSAIDs), such as
aspirin or ibuprofen, are not advised, as they can increase the risk of internal
bleeding.
More severe forms of dengue fever may need:
• intravenous (IV) fluid supplementation, or drip, if the person cannot take
fluids by mouth
• blood transfusion, for patients with severe dehydration

5. Management: No vaccine can protect against dengue fever. Only avoiding
mosquito bites can prevent it. Anyone who lives in or travels to an at-risk area can
use a number of ways to avoid being bitten.
Clothing: Reduce the amount of skin exposed by wearing long pants, long-sleeved
shirts, and socks, tucking pant legs into shoes or socks, and wearing a hat.
Mosquito repellents: Use a repellent with at least 10 percent concentration of
diethyltoluamide (DEET), or a higher concentration for longer lengths of exposure.
Avoid using DEET on young children.
Mosquito traps and nets: Nets treated with insecticide are more effective,
otherwise the mosquito can bite through the net if the person is standing next to it.
The insecticide will kill mosquitoes and other insects, and it will repel insects from
entering the room.
Door and window screens: Structural barriers, such as screens or netting, can keep
mosquitos out.
Avoid scents: Heavily scented soaps and perfumes may attract mosquitos.
Camping gear: Treat clothes, shoes, and camping gear with permethrin, or purchase
clothes that have been pretreated.
Timing: Try to avoid being outside at dawn, dusk, and early evening.
Stagnant water: The Aedes mosquito breeds in clean, stagnant water. Checking for
and removing stagnant water can help reduce the risk.
To reduce the risk of mosquitoes breeding in stagnant water:

6. • turn buckets and watering cans over and store them under shelter so that water
cannot accumulate
• remove excess water from plant pot plates
• scrub containers to remove mosquito eggs
• loosen soil from potted plants, to prevent puddles forming on the surface
• make sure scupper drains are not blocked and do not place potted plants and
other objects over them
• use non-perforated gully traps, install anti-mosquito valves, and cover any
traps that are rarely used
• do not place receptacles under an air-conditioning unit
• change the water in flower vases every second day and scrub and rinse the
inside of the vase
• prevent leaves from blocking anything that may result in the accumulation of
puddles or stagnant water
When camping or picnicking, choose an area that is away from still water.
Dengue has become a global problem since the Second World War and is common
in more than 110 countries, mainly in Asia and South America. Each year between
50 and 528 million people are infected and approximately 10,000 to 20,000 die. The
earliest descriptions of an outbreak date from 1779. Its viral cause and spread were
understood by the early 20th century. Apart from eliminating the mosquitos, work
is ongoing for medication targeted directly at the virus. It is classified as a neglected
tropical disease.