2. DEFINITION
• Dengue fever is a painful, debilitating mosquito-borne disease
caused by any one of four closely related dengue viruses. These
viruses are related to the viruses that cause West Nile infection
and yellow fever.
3. INCIDENCE
• An estimated 390 million dengue infections occur worldwide each year, with
about 96 million resulting in illness.
↣Southeast Asia
↣Southern China
↣Taiwan
↣The Pacific Islands
↣The Caribbean (except Cuba and the Cayman Islands)
↣Mexico
↣Africa
↣Central and South America (except Chile, Paraguay, and Argentina)
4. TRANSMISSION
• Dengue fever is transmitted by the bite of an Aedes mosquito infected with a
dengue virus. The mosquito becomes infected when it bites a person with
dengue virus in their blood. It can’t be spread directly from one person to
another person.
• Period of communicability: it is first 4 to 5 days of illness.
• Incubation period: Varies from 5 to 10 days
Mode of transmission: it is by the bite of infective, female, aedes
mosquito.
5.
6. RISK FACTORS
• Living or traveling in tropical areas.
• Prior infection with a dengue fever virus. Previous infection with a
dengue fever virus increases risk of having severe symptoms if infected
again.
7. SYMPTOMS OF DENGUE FEVER
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
Severe joint and muscle pain
Fatigue
Nausea
• Vomiting
8. Skin rash, which appears two to five days after the onset of fever
Mild bleeding (such a nose bleed, bleeding gums, or easy bruising)
Severe abdominal pain
Persistent vomiting
Bleeding from gums or nose
Blood in urine, stools or vomit
Bleeding under the skin, which might look like bruising
Difficult or rapid breathing
Cold or clammy skin (shock)
Fatigue
Irritability or restlessness
9. INVESTIGATIONS
Platelet count is < 1,00,000 cells/mm3 [Normal=2 to 5 lakhs cells/mm3].
Hematocrit value is increased by 20 percent or more [due to hemoconcentration]
Hypoproteinemia, pleural effusion and ascites constitute the supporting evidence of plasma
leakage.
Real time polymerase chain reaction [RT-PCR]: This is done to detect viral genome in
serum. It is a primary tool to detect virus early in the course of illness. It is a definite proof
of current infection. But this test is not available.
NSI ELISA: Detection of nonstructural protein [NSI-Antigen] in the serum of dengue
fever patients is an useful tool for the diagnosis of acute dengue infections.
IgG ELISA: Samples with negative IgG in acute and a positive IgG in convalescent phase
of the infection are primary dengue infections.
11. Preventing Dengue Fever
There is no vaccine to prevent dengue fever. The best way to prevent the
disease is to prevent bites by infected mosquitoes, particularly if living in or
traveling to a tropical area. This involves protecting and making efforts to
keep the mosquito population down.
Stay away from heavily populated residential areas, if possible.
Use mosquito repellents, even indoors.
When outdoors, wear long-sleeved shirts and long pants tucked into socks.
When indoors, use air conditioning if available.
12. Make sure window and door screens are secure and free of holes. If sleeping
areas are not screened or air conditioned, use mosquito nets.
If have symptoms of dengue, speak to doctor.
To reduce the mosquito population, get rid of places where mosquitoes can
breed. These include old tires, cans, or flower pots that collect rain.
Regularly change the water in outdoor bird baths and pets' water dishes.
13.
14. PREVENTION
• Stay in air-conditioned or well-screened housing. The mosquitoes that carry
the dengue viruses are most active from dawn to dusk, but they can also bite at
night.
• Wear protective clothing. When go into mosquito-infested areas, wear a long-
sleeved shirt, long pants, socks and shoes.
• Use mosquito repellent. Permethrin can be applied to clothing, shoes, camping
gear and bed netting. also buy clothing made with permethrin already in it. For
skin, use a repellent containing at least a 10 percent concentration of DEET.
15. • Reduce mosquito habitat. typically live in and around houses, breeding in
standing water that can collect in such things as used automobile tires. help
lower mosquito populations by eliminating habitats where they lay their eggs.
At least once a week, empty and clean containers that hold standing water.
• 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.
16. • 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 pre-treated.
17. • 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.
18. Vaccine
• In 2016 a partially effective vaccine for dengue fever became commercially
available in the Philippines and Indonesia. It has also been approved for use by
Mexico, Brazil, El Salvador, Costa Rica, Singapore, and Paraguay.
• The vaccine is produced by Sanofi and goes by the brand name Dengvaxia. It is
based on a weakened combination of the yellow fever virus and each of the
four dengue serotypes. Two studies of a vaccine found it was 60% effective and
prevented more than 80 to 90% of severe cases.
• There are ongoing programs working on a dengue vaccine to cover all four
serotypes. Now that there is a fifth serotype this will need to be factored
in. One of the concerns is that a vaccine could increase the risk of severe
disease through antibody-dependent enhancement (ADE). The ideal vaccine is
safe, effective after one or two injections, covers all serotypes, does not
contribute to ADE, is easily transported and stored, and is both affordable and
cost-effective.
19.
20. Treatment for Dengue Fever
• There is no specific medicine to treat dengue infection. pain relievers
with acetaminophen and avoid medicines with aspirin, which could worsen
bleeding. rest, drink plenty of fluids. start to feel worse in the first 24 hours
after fever goes down, should get to a hospital immediately to be checked
for complications.
21. Management
• There are no specific antiviral drugs for dengue; however, maintaining proper
fluid balance is important.
• Treatment depends on the symptoms.
• Those who are able to drink, are passing urine, have no "warning signs" and are
otherwise healthy can be managed at home with daily follow-up and oral
rehydration therapy.
• Those who have other health problems, have "warning signs", or cannot
manage regular follow-up should be cared for in hospital. In those with severe
dengue care should be provided in an area where there is access to an intensive
care unit
22. • Intravenous hydration, if required, is typically only needed for one or two days. The
rate of fluid administration is then titrated to a urinary output of 0.5–1 mL/kg/h,
stable vital signs and normalization of haematocrit. The smallest amount of fluid
required to achieve this is recommended.
• Invasive medical procedures such as nasogastric intubation, intramuscular
injections and arterial punctures are avoided, in view of the bleeding risk.
• Paracetamol (acetaminophen) is used for fever and discomfort while NSAIDs such
as ibuprofen and aspirin are avoided as they might aggravate the risk of bleeding.
• Blood transfusion is initiated early in people presenting with unstable vital signs in the
face of a decreasing hematocrit, rather than waiting for the hemoglobin concentration
to decrease to some predetermined "transfusion trigger" level.
• Packed red blood cells or whole blood are recommended, while platelets and fresh
frozen plasma are usually not. There is not enough evidence to determine
if corticosteroids have a positive or negative effect in dengue fever.
