Dengue

Update

November 7, 2019:  Spain has reported two confirmed cases of dengue in men who have sex with men (MSM) residing in the municipality of Madrid in September.

The most recent detected case is a man who did not travel outside of Spain recently. He developed symptoms mid-September and he was laboratory-confirmed for dengue.

This case is classified as autochthonous.

After confirmation of this case, his partner, a male who presented similar symptoms starting the beginning of September, was tested and confirmed positive for dengue. This case had a recent travel history to Cuba and to the Dominican Republic at the end of August and beginning of September, this case is classified as imported.

Entomological investigations at the place of residence of the men and surroundings were negative; no adult forms of Aedes albopictus were detected. The genetic sequencing confirmed that the virus strain of both cases is identical.

Further investigations showed that the virus is also similar to dengue viruses circulating in Cuba.

The experts in Spain could not identify any case of sexual dengue transmission among MSM in literature and only found a reported case of sexual transmission from a woman to a man in South Korea.

Overview

In 2015, 2.35 million cases of dengue were reported in the Americas alone, of which 10,200 cases were diagnosed as severe dengue, causing 1,181 deaths, which is a fatality rate of 11 percent. 

Currently, there are 46 countries and territories reporting, weekly and systematically, the number of dengue cases to the PAHO.

However, dengue is common in more than 100 countries around the world.

Dengue viruses are spread to people through the bite of an infected Aedes species (Ae. aegypti or Ae. albopictus) mosquito. 

These mosquitoes also spread Zika, chikungunya, and other viruses.

Forty percent of the world’s population, about 3 billion people, live in areas with a risk of dengue. Dengue is often a leading cause of illness in areas with risk.

Dengue is caused by one of four related viruses: Dengue virus 1, 2, 3, and 4.  For this reason, a person can be infected with a dengue virus as many as four times in his or her lifetime.

Dengue outbreaks occasionally occur in the continental United States but is common in the US territories of Puerto Rico, the US Virgin Islands, and American Samoa.

Nearly all dengue cases reported in the 48 contiguous US states were in travelers infected elsewhere. 

In the United States, local dengue outbreaks most recently occurred in Hawaii (2015), Florida (2013), and Texas (2013). Previous dengue outbreaks in the United States have been relatively small and limited to small areas.

2019 cases in the USA.

Symptoms

The most common symptom of dengue is fever with any of the following

  • Nausea, vomiting
  • Rash
  • Aches and pains (eye pain, typically behind the eyes, muscle, joint, or bone pain)
  • Any warning sign
  • Symptoms of dengue typically last 2–7 days.
  • Most people will recover after about a week.

Testing for Dengue

>>Home Testing for Dengue Fever Ulta Labs<<

Dengue fever testing is used to determine whether a person with signs and symptoms and recent potential exposure have been infected with the dengue virus.  Additionally, the World Health Organization recommends that the vaccine only be given to persons with confirmed prior dengue virus infection.  

There are several different types of blood tests that can indicate a dengue infection:

  • Molecular tests for dengue virus (PCR)—detect the presence of the virus itself; these tests can diagnose dengue fever up to 7 days after the onset of symptoms and can be used to determine which of the 4 different serotypes of dengue virus is causing the infection.
  • Antibody tests, IgM and IgG—detect antibodies produced by the immune system when a person has been exposed to the virus; these tests are most effective when performed at least 4 days after exposure.
  • Complete blood count (CBC)—to look for low platelet count typical of the later stages of the illness and to detect the decrease in hemoglobin, hematocrit, and red blood cell (RBC) count (evidence of anemia) that would occur with blood loss associated with severe dengue fever
  • Basic metabolic panel (BMP) – to monitor kidney function and look for evidence of dehydration 

However, there is no FDA cleared test available to determine a previous dengue infection. Available non-FDA cleared tests may yield false-positive results (e.g., due to cross-reactivity with other flaviviruses).

Dengue Clinical Overview

Dengue remains a public health problem in the Americas despite the efforts of the Member States to stop and mitigate the impact of epidemics. The infection can be asymptomatic or show with a broad clinical spectrum that includes serious and non-serious ways of expression. 

After incubation, the disease begins abruptly and goes through three phases: The Febrile, Critical, and Recovery stages, says the PAHO.

1. Febrile Phase

This acute febrile phase lasts 2-7 days and is usually accompanied by skin flushing, erythema, generalized body pain, myalgia, arthralgia, headache, and retro-orbital pain. Minor hemorrhagic manifestations, such as petechiae and ecchymoses in the skin may occur. Patients, who improve after the initial fever, are considered dengue without warning signs.

Problems that may arise in the febrile phase: dehydration, high fever associated with neurological disorders, and seizures in young children.

2. Critical Phase

After the fever abates, the patient may experience within the first 3-7 days of illness and increase of capillary permeability parallel with increased hematocrit levels. This marks the beginning of the critical phase with the highest risk of developing plasma leakage with or without hemorrhage, known as severe dengue. Patients who clinically worsen after the fever subsides should be monitored for warning signs and hemorrhagic manifestations.

Problems that can occur in the critical phase: shock by plasma extravasation, severe bleeding, and serious organ impairment.

3. Recovery Phase

Most patients survive the acute phase (which does not exceed 48 to 72 hours), with timely initiation of judicious fluid management and careful monitoring of the patient during the critical phase, and enter the recovery or convalescent phase. There is a general improvement in the patient: appetite recovers, gastrointestinal symptoms improve, hemodynamic status stabilizes and diuresis increases.

Problems that can occur in the recovery phase are overload (if intravenous fluid therapy has been excessive or has been extended in this period).