Dengue Fever: Introduction, Serotypes, Symptoms, Severity, Lab Diagnosis, Treatment, Prevention, and Keynotes

achaurasiya

3 years ago

Dengue Fever: Introduction, Serotypes, Symptoms, Severity, Lab Diagnosis, Treatment, Prevention, and Keynotes

Introduction of Dengue Fever

Dengue fever is a mosquito (Aedes aegypti)-borne viral disease. It is a major health threat in the tropical and sub-tropical territories of the world, particularly in urban and semi-urban areas. Approximately 50-100 million individuals have been infected with dengue annually (WHO data) and more than 100 countries are at risk of dengue transmission. The following activities are responsible for contributing to fertile breeding areas for the mosquito (Dengue vector)-fast unplanned urbanization and migration of population from rural to urban sectors, climatic changes, no vector control, and poor sanitation services.

Dengue Virus Serotypes

There are four serotypes. They are Dengue serotype-1 (DENV 1), Dengue serotype-2 (DENV 2),Dengue serotype-3 (DENV 3), and Dengue serotype-4 (DENV 4). DENV-2 and DENV-4 are comparatively highly severe than DENV-1 and DENV-3.

Symptoms of Dengue

High fever (up to 104°F or 40°C)- Common
With any of the other signs and symptoms-

Headache
Muscle, bone, or joint pain
Nausea
Vomiting
Swollen glands
Pain behind the eyes
Rash

Severity

Types according to severity are as follows-

Lab Diagnosis of Dengue

Viral Specific Assays-

NS1 Antigen Test: NS1 ( non-structural protein) antigenemia is detectable within 24 hours of infection and up to 9 days following symptom onset. The dengue virus NS1 antigen can be detected by requesting Dengue Virus NS1 Antigen. Blood is used as a separating serum for the testing.
Dengue IgM Test: It is used for the detection of immunoglobulin M (IgM) of present infection.
Dengue IgG Test: It is used for the detection of immunoglobulin G(IgG) of past infection that is not occurring now.
RT-PCR: The dengue serotype can be confirmed by ribonucleic acid (RNA) amplification by RT-PCR using either QunatStudio5 (applied biosystems by the Thermo Fisher Scientific) or BIO-RAD CFX96 Real-Time System (C1000 Touch Thermal Cycler) and other Kit preferred thermocyclers.
Vira Culture: It is a cumbersome and lengthy process. RT-PCR is preferred as a gold standard due to the rapid detection and confirmation.

Viral non-specific assays-In this panel, other than viral tests are performed.

CBC (Complete blood count): A count of the total number of red blood cells (RBCs), white blood cells(WBCs), and platelets present in the blood.
Urine R/E:
LFT: LFT stands for liver function test and it includes SGOT, SGPT, Alkaline phosphate (ALP), Total Protein, and Albumin: Its functions clear from the title, and thus it helps to screen for liver infections, disease prognosis, alcoholic hepatitis, liver cirrhosis, and monitor possible effects of medications.
RFT: It is a renal (kidney) function test. It contains-Sodium, Potassium, Urea, and Creatinine: Healthy kidneys help remove waste from the body and RFT function tests check how well kidneys are working.
Chest X-ray: It is used to detect infection or air collecting in the space around a lung and also cancer. It is also beneficial in chronic lung conditions. e.g. emphysema and cystic fibrosis.
ECG: Electrocardiography (ECG) is normally used alongside other assays to help diagnose and monitor conditions affecting the heart.

Treatment of Dengue Fever

Specific antiviral drugs are lacking to treat dengue infection. Acetaminophen or paracetamol is preferred to control muscle aches, pains, and fever. Non-steroidal anti-inflammatory drugs(NSAIDs) like ibuprofen and aspirin are avoided due to their anticoagulant properties. Supportive care and staying well hydrated are two main conditions for dengue patient management. A complete vaccine for all is still missing. The currently available vaccine is limited to people aged 9-45 years old and even also who have had at least one previous episode of dengue virus infection.  An untimely managed case may increase the risk of people developing severe dengue that will be later potentially fatal.

Prevention

Saving from mosquito bites and vaccines are the most common ways of dengue prevention but currently, the vaccine is not in full phase for everyone due to limitations. So, mosquito bites prevention is the only solution that can be practiced by following methods-

Living in well-screened housing or air-conditioned
Wearing protective clothing
Using mosquito repellent. and
Decreasing mosquito habitat

Keynotes

Three warning signs of severe dengue are severe plasma leakage, severe hemorrhage, and severe organ impairment.
Dengue is transmitted through mosquito bites.
Aedes albopictus is also responsible for to transfer of dengue to a lesser extent.
Dengue fever is also used to be called “breakbone fever due to the severe bone and muscle pain it sometimes can cause.
Risk factors of dengue are living or traveling in tropical areas and having dengue fever in the past.

Rapid NS1 antigen (positive), platelet count (reduction), and patient clinical features (high fever, muscle, bone, or joint pain are strong evidence of dengue.
The addition of clinical lab tests and doctors consultations may vary according to the severity of dengue fever.
The incubation period of dengue is 5-7 days.
The clinical course completes into 3 phases i.e. febrile (2-7 days), critical (1-2 days), and convalescent.
A. aegypti and A. albopictus are also vectors of chikungunya, yellow fever, and Zika viruses.