Dengue Fever Signs, symptoms & treatments

Dr. Muhammad Torequl Islam :
According to a published report on 07 November 2019, Directorate General of Health Services (DGHS) death review committee confirmed 112 deaths so far after reviewing 179 suspected cases, while it received 251 suspected dengue death cases in Bangladesh. Although, we are facing now another pandemic of Covid-19 but, we should be aware of dengue also.
Dengue, a mosquito-borne viral infection, one of the major public health problems in tropical and sub-tropical areas worldwide. Dengue virus (DENV) is transmitted by the female mosquito, Aedes spp. (mainly- Aedes aegypti and Aedes albopictus), that produce saliva containing over 100 unique proteins, including the protein family D7. In a study, it has been found that the 38?kDa D7 protein is upregulated in mosquitoes infected with DENV2 (a serotype of DENV). Therefore, in mosquito, D7 can prevent viral infection, as D7 proteins act against DENV. However, D7 proteins provoke immune responses, which raise anti-D7 antibody levels. These antibodies inhibit the function of D7 proteins, which enhance the transmission of Dengue virus in human. Research evidences suggest that DENV can transmit through blood transfusion through an infected person to an uninfected individual. Pet animals like- dog may be a secondary vector of DENV.
After DENV incubation for 3 to 15 (usually 5 to 8), an infected mosquito is capable of transmitting the virus for the rest of its life (lifespan for adult aedes mosquitos approximately 14 to 30 days depending on environmental conditions). Ae. aegypti is a daytime feeder; its peak biting periods are early in the morning and in the evening before dusk. Female Ae. aegypti bites multiple people during each feeding period. Aedes eggs can remain dry for over a year in their breeding habitat and hatch when in contact with water. Therefore, rainy season is suitable for their breeding. Ae albopictus, on the other hand, is a secondary dengue vector in Asia, North America, and more than 25 countries in the European Region. This Aedes sp. is highly adaptive and, can survive even in cooler temperate regions.
Transmission of DENV in our body causes dengue fever. Symptoms of dengue fever include severe joint and muscle pain, swollen lymph nodes (lymphadenopathy), headache, fever, exhaustion, and rash (itchy). Other signs of dengue fever include bleeding gums, severe pain behind the eyes (retro-orbital), and red palms and soles. Dengue hemorrhagic fever is a more severe form of the viral illness. The symptoms include headache, fever, rash, and evidence of bleeding (hemorrhage) in the body. Petechiae (small red spots or purple splotches or blisters under the skin), bleeding in the nose or gums, black stools, or easy bruising are all possible signs of hemorrhage. This form of dengue fever can be life threatening and can progress to the most severe form of the illness, dengue shock syndrome. Dengue fever also starts with non-specific flu-like symptoms of chills, appetite loss, feeling unwell (malaise), and low backache. Painful aching in the legs and joints occurs during the first hours of illness. The temperature rises quickly as high as 104 ?F (40 ?C), with the relatively low heart rate (bradycardia) and low blood pressure (hypotension). High fever and other signs of dengue last for 2 to 4 days, followed by a rapid drop in body temperature (defervescence) with profuse sweating.
Dengue fever can be difficult to diagnose because its symptoms overlap with those of many other viral illnesses and tropical diseases, such as West Nile virus and Chikungunya fever. Therefore, medical professionals usually make a diagnosis of dengue fever infection on the basis of clinical signs and symptoms associated.
The acute phase of dengue with fever and muscle pain (myalgia) lasts about one to two weeks. A feeling of weakness (asthenia) and fatigue accompany convalescence, and full recovery often takes several weeks. The worst symptoms of the illness typically last 1 to 2 weeks, and most patients will fully recover within several additional weeks. Typical dengue infection is fatal in less than 1% of cases; however, the more severe dengue hemorrhagic fever is fatal in 2.5% of cases. If dengue hemorrhagic fever is not treated, mortality (death) rates can be as high as 20%-50%.
As dengue fever is caused by DENV, therefore no antibiotics can treat it. Antiviral medications are also not indicated for dengue fever. The treatment is concerned with the relief of the signs and symptoms. Home remedies, such as rest and fluid intake (oral rehydration) are important. Only take pain relievers such as aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) under a doctor’s supervision because of the possibility of worsening bleeding complications. Acetaminophen and codeine may be given for severe headache and for joint and muscle pain (myalgia). The U.S. FDA approved Dengvaxia, a vaccine for dengue fever, in May 2019 for use in dengue-endemic areas in persons ranging from 9-45 years of age.
Vitamin B12 and vitamin D deficiency is evident to cause pyrexia of unknown origin, hemolytic anemia, and thrombocytopenia in humans. A supplement of the 4000IU/day of vitamin D may represent an adequate dose to control DENV progression and replication. Scientific reports suggest that the activity of vitamin D is associated with microRNAs, which are fine tuners of immune activation pathways and provide novel mechanisms to avoid the damage that arises from excessive inflammatory responses. Vitamin D has been evident to control of inflammatory cytokine responses during DENV infection of human macrophages. In a clinical study, five patients receiving oral calcium carbonate plus vitamin D3, was evident to improve overall clinical conditions and reduced the duration of signs and symptoms of dengue fever. A recent study suggests that four serotypes of DENV (DENV 1-4) can be treated with riboflavin and ultra violet (UV) light exposure. The papaya leaf extract also treats dengue fever. Alternatively, we can use mosquito repellant (e.g., Odomos) to avoid mosquito biting during daytime.
This year DENV is detected as a monster in Bangladesh. Therefore, more precautions should be taken before coming the rainy season to destroy DENV’s vectors. Historically, pharmaceutical companies did not give much concern on mosquito-borne viral infections. More research should be carried out to discover and develop anti-DENV drugs from various sources. And adequate steps should be taken into account to maintain a healthy environment throughout Bangladesh.

(Dr. Muhammad Torequl Islam is Assistant Professor, Department of Pharmacy, Bangabandhu Sheikh Mujibur Rahman Science and Technology University. E-mail: [email protected])