Individuals with dengue generally have a history of either living in or travelling recently to areas that have been denoted as endemic [5]. The incubation period for the condition is 3-14 days.

Symptoms that occur two weeks after departure of the individual from an endemic area may not be due to the dengue virus.

Most patients experience erythematous mottling of the skin, chills and facial flushing. Facial flushing can be regarded as one of the most specific indicators of dengue fever. The chills may last for 2-3 days. Maculopapular rash and nonspecific febrile syndrome is often seen in children that are younger than 15 years of age.

Standard cases of dengue begin with onset of fever, chills, aching of the back, head, extremities and other symptoms [6]. The fever generally lasts for 2-7 days and so fever longer than 10 days may not be due to dengue.

Other findings may include injected conjunctivae, inflamed pharynx, Lymphadenopathy, nausea and vomiting, dry or non-productive cough, tachychardia and brachychardia.

• Splenomegaly

  Tender hepatomegaly is observed in all patients and splenomegaly in some. Shock, plasma leakage and marked thrombocytopenia are more common in children, whereas internal haemorrhage is more frequent as age increases ( Hammond et al., 2005 ). [ncbi.nlm.nih.gov]

  Tender hepatomegaly is observed in almost all patients and splenomegaly may be seen in some. [doi.org]

• Generalized Lymphadenopathy

  Dengue fever usually results in abrupt onset of high fever, headache, myalgias, arthralgias, and generalized lymphadenopathy, followed by a rash that appears with a 2nd temperature rise after an afebrile period. [msdmanuals.com]

• Fever

  Dengue fever is a virus-caused disease that is spread by mosquitoes. Dengue fever is caused by 1 of 4 different but related viruses. [nlm.nih.gov]

  This paper reviews the changing epidemiology of dengue and dengue hemorrhagic fever by geographic region, the natural history and transmission cycles, clinical diagnosis of both dengue fever and dengue hemorrhagic fever, serologic and virologic laboratory [ncbi.nlm.nih.gov]

  That shows that dengue fever should be considered for people returning from a tropical location with fever in the absence of malaria. In 2012 a large outbreak of the dengue fever occurred in Madeira. [flexikon.doccheck.com]

• High Fever

  This is characteristic of Dengue fever. The acute phase of the illness causes extreme muscle pains and high fevers. These may last up to two weeks. [indianexpress.com]

  Dengue fever begins with a sudden high fever, often as high as 105°F (40.5°C), 4 to 7 days after the infection. A flat, red rash may appear over most of the body 2 to 5 days after the fever starts. [nlm.nih.gov]

  He just came back home from a travel to Southeast Asia 1 week ago and had presented with chill, high fever (temperature, 39.6°C), arthralgia, myalgia, and skin rash a few days before. [ncbi.nlm.nih.gov]

  It begins with a sudden onset of high fever that usually lasts between 3-5 days, and is accompanied by the following symptoms: High fever, possibly as high as 106 °F (41 °C) Severe headache Possible bleeding from the mouth and nose Retro-orbital pain [pacificmedicalacls.com]

• Fatigue

  Other symptoms include: Fatigue Headache (especially behind the eyes) Joint aches (often severe) Muscle aches (often severe) Nausea and vomiting Swollen lymph nodes Cough Sore throat Nasal stuffiness Tests that may be done to diagnose this condition include [nlm.nih.gov]

  "Post-infectious fatigue syndrome in dengue infection." Journal of Clinical Virology 38 (2007): 1-6. postinfection_fatigue_syndrome.pdf>. Shepherd, Suzanne Moore. "Dengue." Medscape.com. Oct. 5, 2015.. Switzerland. World Health Organization. [medicinenet.com]

  When accounting for disability from moderate and severe acute dengue, and post-dengue chronic fatigue, 566 000 (186 000-1 415 000) years lived with disability were attributable to dengue in 2013. [ncbi.nlm.nih.gov]

  Recovery phase Fatigue and depression may last for weeks, particularly in adults. [patient.info]

• Chills

  He just came back home from a travel to Southeast Asia 1 week ago and had presented with chill, high fever (temperature, 39.6°C), arthralgia, myalgia, and skin rash a few days before. [ncbi.nlm.nih.gov]

  Most patients experience erythematous mottling of the skin, chills and facial flushing. Facial flushing can be regarded as one of the most specific indicators of dengue fever. The chills may last for 2-3 days. [symptoma.com]

  The disease is typified by the sudden onset of a severe fever, chills, headache, pain behind the eyes (retro-orbital pain), photophobia, and joint and muscle pain. [web.archive.org]

  The patient has chills or chilly sensations, a fever, exhaustion, diarrhea, and/or vomiting. Pain behind the eyeballs (postorbital) occurs on moving the head. The head, lower back, legs and joints ache. The patient feels very weak. [rarediseases.org]

  For 2 to 3 days, you'll feel weak and tired and have: High fever and chills Severe headache Pain when you move your eyes Severe aching pain in your back, legs, and joints—these are so painful that dengue was nicknamed “breakbone fever” Rash on your face [msdmanuals.com]

• Lymphadenopathy

  Dandy fever: An acute mosquito- borne viral illness of sudden onset that usually follows a benign course with headache, fever, prostration, severe joint and muscle pain, swollen glands (lymphadenopathy) and rash. [medterms.com]

  Dengue, a major public health problem throughout subtropical and tropical regions, is an acute infectious disease characterized by biphasic fever, headache, pain in various parts of the body, prostration, rash, lymphadenopathy, and leukopenia. [ncbi.nlm.nih.gov]

  SUMMARY Dengue, a major public health problem throughout subtropical and tropical regions, is an acute infectious disease characterized by biphasic fever, headache, pain in various parts of the body, prostration, rash, lymphadenopathy, and leukopenia. [doi.org]

• Respiratory Insufficiency

  This situation remained for 15 minutes, progressing to respiratory insufficiency, with consequent absence of peripheral pulses. Death was confirmed approximately 40 minutes after the first symptoms. [ncbi.nlm.nih.gov]

• Vomiting

  Gastrointestinal bleeding may lead to vomiting of blood (hematemesis) and passing of dark stools stained with blood pigment (melena). [rarediseases.org]

  Abdominal pain and vomiting were more common in patients developing DHF. Mean platelet count was lower in adult, but not pediatric patients developing DHF. [ncbi.nlm.nih.gov]

  difficulty breathing, or blood in your nose, gums, vomit or stools. [mayoclinic.org]

• Nausea

  Fever was the most common clinical feature followed by headache, myalgia, backache, nausea and abdominal pain. Petechia was most common haemorrhagic manifestation. [ncbi.nlm.nih.gov]

  These forms of the disorder are characterized by sudden fever, headache, nausea, vomiting, and abdominal pain. Coughing, throat infection and difficulty in breathing also occur. [rarediseases.org]

  There may also be gastritis with some combination of associated abdominal pain, nausea, vomiting, or diarrhea. [denguevirusnet.com]

  Patients with dengue usually present with fever, headache, rash, nausea, vomiting, aches and pains. [dermnetnz.org]

• Abdominal Pain

  Rectus sheath hematoma is an uncommon and often clinically misdiagnosed cause of abdominal pain. [ncbi.nlm.nih.gov]

• Constipation

  Constipation is occasionally reported; diarrhea and respiratory symptoms are infrequently reported and may be due to concurrent infections. The initial temperature may rise to 102 to 105°F, and fever may last for 2 to 7 days. [cmr.asm.org]

• Hypotension

  On admission physical examination revealed fever, dry mucosa, moderate hypotension and tachycardia. In the laboratory test results, leukopoenia, thrombocytopoenia and elevated transaminases were observed. [ncbi.nlm.nih.gov]

  Hypotension is a more frequent complication of DHF than severe hemorrhage. Bibliography CDC. Imported dengue —United States, 1999 and 2000. MMWR Morbid Mortal Wkly Rep 2002; 5:281-3. Ellerin T, Hurtado R, Lockman S, Baden L. [web.archive.org]

  The temperature rises quickly as high as 40° C, with relative low heart rate (bradycardia) and low blood pressure (hypotension). [denguevirusnet.com]

  However, once hypotension develops, systolic blood pressure rapidly declines, and irreversible shock and death may ensue despite resuscitation. [wwwnc.cdc.gov]

• Tachycardia

  On admission physical examination revealed fever, dry mucosa, moderate hypotension and tachycardia. In the laboratory test results, leukopoenia, thrombocytopoenia and elevated transaminases were observed. [ncbi.nlm.nih.gov]

  […] epigastralgia (pain in the upper abdomen) Bleeding of the nose, mouth or gums Bleeding or bruising under the skin Hematemesis (vomiting blood) and vomiting without blood Dry skin and mucous membranes Excessive thirst Dehydration Insomnia and restlessness Tachycardia [pacificmedicalacls.com]

  Outcomes associated with amiodarone and lidocaine in the treatment of in-hospital pediatric cardiac arrest with pulseless ventricular tachycardia or ventricular fibrillation. [doi.org]

• Cyanosis

  A few minutes after these non-specific symptoms, the patient started tonic-clonic convulsions and had cyanosis, a substantial increase in body temperature to the touch, cold sudoresis, sphincter relaxation, and unconsciousness. [ncbi.nlm.nih.gov]

  Shock may occur 2 to 6 days after the beginning of the fever, with sudden collapse, cool clammy extremities (the trunk is often warm), a weak pulse, and bluish discoloration of the skin around the mouth (cyanosis). [rarediseases.org]

  Children with profound shock are often somnolent, exhibit petechiae on the face, and have perioral cyanosis. [cmr.asm.org]

• Retroorbital Pain

  The commonest form has an incubation period of 5-8 days followed by the onset of a fever, violent headache, chills, retroorbital pain, with a rash developing after 3-4 days. [web.archive.org]

  Other signs and symptoms may include severe headache; retroorbital pain; muscle, joint, and bone pain; macular or maculopapular rash; and minor hemorrhagic manifestations, including petechiae, ecchymosis, purpura, epistaxis, bleeding gums, hematuria, [wwwnc.cdc.gov]

• Conjunctival Injection

  Bulbar and palpebral conjunctival injection and a transient flushing or pale pink macular rash (particularly of the face) may occur. Cervical, epitrochlear, and inguinal lymph nodes are often enlarged. [msdmanuals.com]

• Petechiae

  An 8-year-old girl was admitted with fever, myalgia and petechiae. Dengue virus IgM antibodies were positive. She recovered completely, but her thrombocytopenia persisted. Six weeks later she became pancytopenic. [ncbi.nlm.nih.gov]

  The test is considered positive when ≥20 petechiae per 2.5 cm 2 are seen. Even in profound shock it can be negative or just mildly positive. [patient.info]

  The number of petechiae that form within a 2.5-cm diameter circle are counted; > 20 petechiae suggests capillary fragility. Complete blood count, coagulation tests, urinalysis, liver tests, and dengue serologic tests should be done. [msdmanuals.com]

• Flushing

  Dengue is an arboviral infection that classically presents with fever, joint pain, headaches, skin flush and morbilliform rashes. [ncbi.nlm.nih.gov]

  Most patients experience erythematous mottling of the skin, chills and facial flushing. Facial flushing can be regarded as one of the most specific indicators of dengue fever. The chills may last for 2-3 days. [symptoma.com]

  […] infection is endemic in more than 100 countries, particularly the South East Asia region, western Pacific region, and the Americas The incubation period is 3-14 days (average 7 days) Clinical features include fever, headache, myalgia/arthralgia, and skin flushing [doi.org]

  The illness often begins with a sudden rise in temperature accompanied by facial flush and other flu-like symptoms. The fever usually continues for two to seven days and can be as high as 41°C, possibly with convulsions and other complications. [denguevirusnet.com]

  The victim may appear flushed at the onset of the fever and a rash may appear on the torso after 3-4 days and spread to the rest of the body. Lymph nodes are often inflamed. [web.archive.org]

• Skin Rash

  He just came back home from a travel to Southeast Asia 1 week ago and had presented with chill, high fever (temperature, 39.6°C), arthralgia, myalgia, and skin rash a few days before. [ncbi.nlm.nih.gov]

  Skin rash 8. Low blood pressure Diagnosis and treatment Doctors can diagnose dengue infection with a blood test. [food.ndtv.com]

• Pruritus

  Intense pruritus followed by desquamation on the palms of the hands and soles of the feet may occur. Hemorrhagic manifestations in dengue fever patients are not uncommon and range from mild to severe. [cmr.asm.org]

• Myalgia

  An 8-year-old girl was admitted with fever, myalgia and petechiae. Dengue virus IgM antibodies were positive. She recovered completely, but her thrombocytopenia persisted. Six weeks later she became pancytopenic. [ncbi.nlm.nih.gov]

• Arthralgia

  A 60-year-old Sri Lankan man presented with a history of fever, arthralgia, and generalized malaise of 2 days duration. [ncbi.nlm.nih.gov]

• Bone Pain

  Symptoms include high fever, severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding in the gums or nose. [abcnews.go.com]

  The infection is characterized by flu-like symptoms which include a sudden high fever coming in separate waves, pain behind the eyes, muscle, joint, and bone pain, severe headache, and a skin rash with red spots. [iamat.org]

  Dengue—which causes searing eye, head and bone pain, and has no cure—spreads when a mosquito sucks the blood of someone who’s already carrying the virus, and then bites another person who hasn’t yet been infected. [qz.com]

  Symptoms of dengue include high fever, severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash and mild bleeding involving the nose or gums, and easy bruising. [cdc.gov]

• Back Pain

  Symptoms Typical symptoms of dengue fever include: Fever with temperatures reaching as high as 41ºC (105.8ºF) Headache Eye pain Pain in the bones, muscles and joints. The back pain is characteristic of the infection. [news-medical.net]

  Headache, back pain and muscle aching may be so severe as to require narcotics. [web.archive.org]

  Pain behind or in back of the eyes is also a common symptom. Some individuals may develop a sore throat, vomiting, nausea, abdominal and/or back pain, and loss of appetite. [emedicinehealth.com]

  Symptoms of the disease appear suddenly and include high fever, chills, headache, eye pain, red eyes, enlarged lymph nodes, a red flush to the face, lower back pain, extreme weakness, and severe aches in the legs and joints. [encyclopedia.com]

• Vaginal Bleeding

  The most common symptom is bleeding from the nose, mouth, and gums, but accumulation of fluids in the abdomen or lungs, bleeding in the intestinal tract, vaginal bleeding, or bleeding under the skin are also possible. [en.wikivoyage.org]

  The commonest site of haemorrhage is the gastrointestinal tract, which manifests as haematemesis or melaena, followed by epistaxis. 47, 50, 55 Vaginal bleeding is commonly reported in females. 56 Convalescence in DHF is usually short and uneventful. 2 [doi.org]

• Headache

  Dengue is an arboviral infection that classically presents with fever, joint pain, headaches, skin flush and morbilliform rashes. [ncbi.nlm.nih.gov]

  Dandy fever: An acute mosquito- borne viral illness of sudden onset that usually follows a benign course with headache, fever, prostration, severe joint and muscle pain, swollen glands (lymphadenopathy) and rash. [medterms.com]

  Dengue fever symptoms include sudden onset of a fever that may last from 2 to 7 days with intense headache, joint and muscle pain, and a rash. Mild bleeding of the nose or gums may occur. [health.ny.gov]

The signs and symptoms of dengue fever are nonspecific [7]. Therefore attempting a laboratory confirmation of the dengue infection is vital. Criteria to be met in the laboratory for diagnosis to be confirmed include:

• Detection of viral genomic sequences in autopsy tissue, serum, or cerebral spinal fluid (CSF) samples through polymerase chain reaction (PCR)
• Demonstration of dengue virus antigen in autopsy tissue via immunohistochemistry or immunofluorescence or in serum samples via enzyme immunoassay (EIA)
• Demonstration of a fourfold or greater change in reciprocal immunoglobulin G (IgG) or immunoglobulin M (IgM) antibody titers to one or more dengue virus antigens in paired serum samples
• Isolation of the dengue virus from serum, plasma, leukocytes, or autopsy samples

The following laboratory tests equally have to be performed:

• Metabolic panel

• Complete blood count (CBC)
• Serum protein and albumin levels
• Liver panel and disseminated intravascular coagulation (DIC) panel

Dengue fever characteristically shows thrombocytopenia with platelet count < 100 x 109/L. Leukopenia and mild or moderate increases in level of alanine aminotransferase values can also be found [8].

• Leukopenia

  He initially exhibited symptoms of leukopenia, thrombocytopenia and concomitant rhabdomyolysis and after admission simultaneously developed a biphasic fever and systemic erythema. [ncbi.nlm.nih.gov]

• Neutropenia

  Transient neutropenia has been described in a few cases of arboviruses. However, prolonged and severe neutropenia (<500/mm3) has rarely been reported in dengue fever, especially in the returned traveler in Europe. [ncbi.nlm.nih.gov]

  Clinical laboratory findings associated with dengue fever include a neutropenia followed by a lymphocytosis, often marked by atypical lymphocytes. [cmr.asm.org]

Dengue fever is usually a self-limited illness. As there is presently no antiviral drug available, treatment is supportive, with analgesics, fluid replacement, and bed rest.

The dengue fever condition is a self-limiting one and the mortality rate is less than 1%. When adequately treated, dengue hemorrhagic fever has a mortality rate of 2-5%. If left untreated, dengue hemorrhagic fever has a mortality rate which is as high as 50% [9].

Dengue fever is caused by the DENV (dengue virus). This virus is a single-stranded RNA virus of the family Flaviviridae and genus Flavivirus. The type specific virus is yellow fever [3]. The dengue virus has 4 stereotypes that are antigenically distinct. Each of the stereotypes have several different genotypes and disease severity is affected by the sequence of infection with different serotypes.

An important risk factor for infection is living in endemic areas of the tropics where the vector mosquito thrives. The explosive global population growth and poorly planned urbanization is what brings the human host and mosquito close to each other.

Increase in air travel also makes it easy for infectious diseases to be transported between different groups.

United States

In the U.S dengue occurs principally in travellers who have just returned from areas marked as endemic. According to the CDC, 244 confirmed cases of travel related dengue were reported in the U.S within 2006 to 2008.

Over the past 20 years, there has been an increase in the cases of Dengue amongst returning U.S travellers. The condition is also responsible for majority of febrile illnesses in individuals returning from South America, Asia and the Caribbean [2].

International

500,000 cases of dengue hemorrhagic fever and 50-100 million cases of dengue fever occur worldwide each year with an approximated 22,000 deaths recorded yearly too. 40% of the world’s population are at risk of dengue infection (an estimated 2.5-3 billion people spread across 112 tropical and subtropical countries around the world).

The only continents where dengue transmission is not experienced are Antarctica and Europe. The WHO rates dengue as the most important viral disease transmitted by mosquito in the world. Dengue has continued to pose a challenge to world health as it has increased 30 fold over the past 30 years.

As mentioned above, dengue fever is a mosquito-borne viral disease that is caused by one of four dengue virus types [4]. Homotypic immunity is conferred on an individual after infection by one type of this virus. There is also brief period of partial heterotypic immunity. It is possible for several serotypes to be in circulation in the event of an epidemic.

Dengue fever develops like majority of bacterial and viral illnesses. Fever sets in on the third day of illness and may last for 5-7 days. It abates with the end of viremia. In children, the fever is intermittent, abating for a day before recurring. This is a pattern that is known as saddleback fever. The saddleback fever is more commonly seen in dengue hemorrhagic fever cases.

Thrombocytopenia, lymphopenia and leukopenia are equally common with dengue fever. It is believed that this happens due to the direct destructive actions of the virus on bone marrow precursor cells.

There are not yet any vaccines to prevent infection and the most effective protective measures are those that avoid mosquito bites.

Dengue fever is a mosquito-borne tropical disease that is caused by the dengue virus. It is also referred to as breakbone fever. 

Dengue fever is transmitted by the A. aegypti mosquito. The dengue virus is of 5 types. When an individual is infected with one type, he or she gets lifelong immunity to that type. Infection also brings immunity to the other virus forms, albeit temporary [1]. Infection by another type of the virus after an earlier case leads to an increased risk of severe complications.

There are no commercially available vaccines. Therefore prevention is achieved by reducing or destroying the mosquito habitat and also limiting the exposure of individuals to bites.

Dengue vascualopathy or Dengue hemorrahgic fever brings about vascular leakage in patients and this often results in serous effusions and hemoconcentration which may lead to a collapse of the circulatory system. This happens in conjuction with severe hemorrhagic complications leading to dengue shock syndrome, a condition with greater risk of fatality.

Individuals who have suffered dengue fever in the past should avoid mosquito bites through the use of repellants and other domestic vector control techniques especially when travelling to areas that are endemic [10]. This is because such individuals are at risk of developing the dengue shock syndrome or dengue hemorrhagic fever if they get infected with a different dengue strain in the future.

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4. Kyle JL, Harris E. Global spread and persistence of dengue. Annu Rev Microbiol. 2008;62:71-92.
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10. Guzman MG, Halstead SB, Artsob H, et al. (December 2010). "Dengue: a continuing global threat". Nature Reviews Microbiology 8 (12 Suppl): S7–S16.