Dengue Shock Syndrome

What is Dengue Shock Syndrome?

Dengue Shock Syndrome is a collection of symptoms resulting from a dengue infection. Its symptoms – including hemorrhaging – resemble those you’d see after an accident, when someone is ‘in shock’. Typically, older children or adults suffer 2–7 days of high fever and show two or more of the following symptoms:

  • severe headache,
  • retro-orbital eye pain,
  • myalgias,
  • arthralgias,
  • a diffuse erythematous maculo-papular rash, and
  • mild hemorrhagic manifestation.
  • Subtle, minor epithelial hemorrhage, in the form of petechiae, are often found on the lower extremities (but may occur on buccal mucosa, hard and soft palates and or subconjunctivae as well), easy bruising on the skin, or the patient may have a positive tourniquet test.
  • Other forms of hemorrhage such as epistaxis, gingival bleeding, gastrointestinal bleeding, or urogenital bleeding can also occur, but are rare.
  • Leukopenia is frequently found and may be accompanied by varying degrees of thrombocytopenia.
  • Children may also present with nausea and vomiting.
  • Patients with DF do not develop substantial plasma leak (hallmark of DHF and DSS, see below) or extensive clinical hemorrhage.
Dengue virus image
Dengue virus: Dengue Shock Syndrome

Serological testing for anti-dengue IgM antibodies or molecular testing for dengue viral RNA or viral isolation can confirm the diagnosis, but these tests often provide only retrospective confirmation, as lab results are typically not available until well after the patient has recovered.

Clinical presentation of DF and the early phase of DHF are similar, and therefore it can be difficult to differentiate between the two forms early in the course of illness. With close monitoring of key indicators, the development of DHF can be detected at the time of defervescence so that early and appropriate therapy can be initiated.

The key to successfully managing patients with dengue infection and lowering the probability of medical complications or death due to DHF or DSS is early recognition and anticipatory treatment(For more detailed guidance on management for DF please see the recommended treatment courses for DHF in the links listed below.)

Dengue Hemorrhagic Fever (DHF) or Dengue Shock Syndrome (DSS): The third clinical presentation results in the development of DHF, which in some patients progresses to DSS. Vigilant is critical for identifying warning signs of progressing illness and early symptoms of DHF which are very similar to those of DF. Case Definitions Page

There are three phases of DHF:

  1. the Febrile Phase;
  2. the Critical (Plasma Leak) Phase; and
  3. the Convalescent (Reabsorption) Phase.

The Febrile Phase: Early in the course of illness, patients with DHF can present much like DF, but they may also have hepatomegaly without jaundice (later in the Febrile Phase). The hemorrhagic manifestations that occur in the early course of DHF most frequently consist of mild hemorrhagic manifestations as in DF. Less commonly, epistaxis, bleeding of the gums, or frank gastrointestinal bleeding occur while the patient is still febrile (gastrointestinal bleeding may commence at this point, but commonly does not become apparent until a melenic stool is passed much later in the course). Dengue viremia is typically highest in the first three to four days after onset of fever but then falls quickly to undetectable levels over the next few days. The level of viremia and fever usually follow each other closely, and anti-dengue IgM anti-bodies increase as fever abates.

The Critical (Plasma Leak) Phase: About the time when the fever abates, the patient enters a period of highest risk for developing the severe manifestations of plasma leak and hemorrhage. At this time, it is vital to watch for evidence of hemorrhage and plasma leak into the pleural and abdominal cavities and to implement appropriate therapies replacing intravascular losses and stabilizing effective volume. If left untreated, this can lead to intravascular volume depletion and cardiovascular compromise. Evidence of plasma leak includes sudden increase in hematocrit (≥20% increase from baseline), presence of ascites, a new pleural effusion on lateral decubitus chest x-ray, or low serum albumin or protein for age and sex. Patients with plasma leak should be monitored for early changes in hemodynamic parameters consistent with compensated shock such as increased heart rate (tachycardia) for age especially in the absence of fever, weak and thready pulse, cool extremities, narrowing pulse pressure (systolic blood pressure minus diastolic blood pressure <20 mmHg), delayed capillary refill (>2 seconds), and decrease in urination (i.e., oliguria). Patients exhibiting signs of increasing intravascular depletion, impending or frank shock, or severe hemorrhage should be admitted to an appropriate level intensive care unit for monitoring and intravascular volume replacement. Once a patient experiences frank shock he or she will be categorized as having DSS. Prolonged shock is the main factor associated with complications that can lead to death including massive gastrointestinal hemorrhage. Interestingly, many patients with DHF/DSS remain alert and lucid throughout the course of the illness, even at the tipping point of profound shock. CDC:

Doctors: See case definition for DHF and DSS. Adobe PDF fileExternal Web Site IconThere are no good videos about dengue shock syndrome, but this text video might help:

Dengue Bribery in Philippines?

Was there Dengue bribery in Philippines? Questions hover over Asia’s first dengue vaccination program in Philippines.

Dengue Mosquito
Dengue Mosquito: Asian Tiger

The Aedes aegypti mosquito carries the dengue virus, Zika virus, and other mosquito-borne illnesses as it travels from person to person.

Asia’s first dengue vaccine has been distributed in a mass school-based immunization program in the Philippines. So far, the program appears to be running without difficulties, but some health professionals are concerned that the vaccine was released before researchers could ensure its long-term safety.

From the beginning, the vaccine’s French manufacturer Sanofi Pasteur has been concerned about a potential problem with the vaccine — that while it could help prevent dengue initially, it could later increase the severity of the disease, according to Dr. Antonio Dans, a professor at the University of the Philippines College of Medicine.

“The real dengue we are afraid of is severe dengue, not the mild ones,” Dans said in a statement. “If a vaccine prevents mild disease but causes severe dengue, we shouldn’t be using it at all.”

This possibility is being monitored by the vaccine’s developer, Dans said in a news release; and since the phenomenon may happen a full three years after immunization occurs, it will take some time to study the vaccine’s long term effects.

However, as the virus infects as many as 400 million people annually, the vaccine for dengue has been awaited with increasing impatience. In an effort to stem the spread of the virus in regions heavily burdened by the disease, the WHO recommended that the drug be introduced in dengue-endemic sites while awaiting prequalification.

According to the organization, the WHO is now waiting on an application from the vaccine’s manufacturer.

The vaccine, Dengvaxia, has also been registered in Mexico, Brazil and El Salvador. Now, the Philippines — which in 2015 saw an almost 60 percent increase in dengue cases from the year prior — has become the first to make the vaccine commercially available.

“This initiative sends a strong message to the rest of the … world that dengue vaccination is a critical addition to integrated disease prevention efforts,” according to a statement from the vaccine’s developer Sanofi Pasteur.

The official launch of the school-based immunization program on April 4 sidestepped a prequalification procedure by the WHO, as is standard for new vaccines to ensure safety and effectiveness. This raised additional concern from some medical professionals, according to Philippine media network GMA, who say the immunization program should not have skipped the prequalification process, especially considering such limited knowledge of the vaccine’s long-term side effects.

Still, the company said the Dengvaxia vaccine, which took 20 years and $1.8 billion to develop, should prevent 80 percent of dengue-related hospitalizations and up to 93 percent of cases of severe hemorrhagic dengue fever. The vaccine is designed for people ages 9 to 45, and is administered in three separate doses over a six-month period.

Since the start of the immunization program last month, Dengvaxia has been administered to more than 200,000 grade-school students in the capital city of Manila. Of 17,000 people who were injected with the vaccine in the Philippines in February as part of the clinical study, just 27 developed side effects, Health Undersecretary Vicente Belizario told reporters.

According to Health Minister Janette Garin, the $103 million program aims to administer the first dose of the vaccine to 1 million children by June.

The history of developing a vaccine for dengue has been wrought with challenges. An effective vaccine must protect against four closely related viruses that can cause the disease, and researchers have had limited understanding of how the virus affects the immune system. Among other barriers making vaccine development more difficult, there are no easily measurable sign (such as antibodies) that a person is immune to the disease.

The WHO estimates that dengue fever, the world’s most common mosquito-borne virus, infects an estimated 390 million people around the world each year. So far this year, more than 33,000 dengue cases have been recorded in the Philippines alone. Read more…

 

Dengue Pandemic

Are we looking at a Dengue Pandemic soon?

Will Climate Change Bring a Dengue Pandemic?

Dengue Pandemic Vector
Dengue Pandemic Vector

Dr Shahera Banu, and colleagues from QUT’s Faculty of Health, investigated the impact of climate change on transmission of the mosquito-borne disease and found there would be “devastating” consequences. Dr Banu analysed high-risk areas for dengue fever transmission in the Asia-Pacific region, with particular focus on Dhaka, the capital of Bangladesh and a megacity of 11.8 million people.

Using modelling from the Intergovernmental Panel on Climate Change (IPCC) which predicts an annual average temperature rise for the South Asia region of 3.3 degrees by 2100, the research found there would be a swell of dengue cases. The research has been published in the journals PLOS One and Environment International.

“Without any changes in the socio-economic situation, by the end of this century there will be a projected annual increase of 16,030 cases in Dhaka,” Dr Banu said.”The consequence of this will be devastating.”

The warmer temperatures and humidity would provide optimal conditions for mosquitos to thrive, Dr Banu said. The research collected the monthly number of dengue cases in Dhaka from January 2000 to December 2010 and estimated 377 cases attributable to temperature variation in 2010.

“Assuming a 1 degree temperature increase in 2100, we project an increase of 583 cases, for 2 degrees it would be 2,782 but it is at 3.3 degrees, a rise the IPCC has projected, that will have an overwhelming impact,” Dr Banu said.”Our results show that the monthly temperature and humidity were significantly associated with the monthly dengue incidence in Dhaka.

“These results are consistent with findings of other studies and may assist to forecast dengue outbreaks in different regions.”

Dengue Epidemic Viral Diagnosis
Dengue Epidemic Viral Diagnosis

Dr Banu said places with similar weather conditions to Dhaka would also likely be at risk from a climate change-driven increase in dengue cases.”We’re hopeful this research will be helpful for improving surveillance of dengue fever and control through effective management and community education programs in Bangladesh and other countries in a similar situation,” she said.

Here’s a report about Singapore’s recent, unexpected dengue outbreak: Epidemic resurgence of dengue fever in Singapore in 2013-2014: A virological and entomological perspective. Long story short: The culmination of the latest epidemic is likely to be due to a number of demographic, social, virological, entomological, immunological, climatic and ecological factors that contribute to DENV transmission. A multi-pronged approach backed by the epidemiological, virological and entomological understanding paved way to moderate the case burden through an integrated vector management approach.

New Rapid Test for Dengue

There’s a new rapid test for Dengue!

Singapore’s respected Agency for Science, Technology and Research, A*STAR, announced (Jan 29) a new rapid test kit that will allow dengue diagnosis in 20 minutes.

The paper-based disposable device was developed by A*STAR’s Institute of Bioengineering and Nanotechnology (IBN)  and detects dengue antibodies in saliva – delivering a positive or negative reading in less than half an hour – rather than the 24 hours required for current lab tests. And…unlike blood samples, saliva can be easily and painlessly collected.

The kit also detects dengue antibodies from early-stage secondary infections of dengue. This is a big deal because patients who have previously contracted different strains of the dengue virus stand a higher risk of developing dengue hemorrhagic fever or severe dengue – and suffering dengue shock syndrome.

IBN Executive Director Professor Jackie Y. Ying said, “The ability to differentiate between primary and secondary dengue infections makes it a valuable early diagnosis tool that would help to ensure timely treatment and proper care of patients”.

Early diagnosis is crucial as the incubation period before dengue symptoms generally develop 4–10 days days after infection, so timely intervention can prevent further complications. Dengue is fast-acting so dengue sufferers will benefit hugely from a fast, cheap test and early intervention.

A*STAR plans to make the test as easy to use as over-the-counter pregnancy or fertility test kits. They’re also adapting it to detect other infectious diseases.

The institute is currently collaborating with ARKRAY Inc., a Japanese disease detection firm, to commercialise the new rapid test kit for dengue. Stay tuned!

 

Here’s an America version of a rapid dengue detection test that sounds like very good news, indeed:

Paper Test Quickly Detects Ebola, Dengue, And Yellow Fever

Silver nanoparticles on paper reveal three diseases with the speed and simplicity of a home pregnancy test

silver nanoparticles
The sensor exploits the size-dependent optical properties of silver nanoparticles to detect yellow fever, Ebola and dengue – Credit: RSC
Researchers in the US have developed a silver nanoparticle-based paper test to simultaneously detect dengue, yellow fever and Ebola. This could provide a cheap and reliable diagnosis for all three diseases, that’s as quick as a home pregnancy test.The Ebola epidemic in West Africa underscores an urgent need for rapid diagnostics; quick identification and patient isolation can benefit the sick and the healthy. However, dengue, yellow fever and Ebola all initially manifest as a fever and headache, so are easily mixed up.
Now, this huge problem has a tiny solution – an 8×3cm lateral flow test. Lee Gehrke and his team at the Massachusetts Institute of Technology and Harvard Medical School adapted the traditional single marker lateral flow test to diagnose several diseases at once. It costs $2, takes 10 minutes, and there is no need for a power supply, trained specialist or.. read more in Scientific American…

Tainan to use antigen test for early diagnosis of dengue

Southern Taiwan’s Tainan city said Thursday it will introduce 5,000 paper-based dengue NS1 antigen test kits for early diagnosis of dengue fever, which has raged the southern Taiwan city with 2,381 confirmed cases so far this year.

The tests, which use a color change to indicate the positive presence of the dengue NS1 antigen, will be able to identify patients at an early stage and thus prevent the disease from spreading, said Lin Sheng-che, head of Tainan’s Department of Health.

The weather is “on the side of the mosquito,” Lin said, explaining that constant rain and humidity is favorable for vector breeding.

According to the department’s latest data Thursday, 30 out of the city’s 37 districts have reported dengue fever cases.

Dengue fever has claimed the lives of four people so far this year–all in Tainan. Most of whom were elderly and suffered from other chronic illnesses. Read more…

Watch this video of an existing dengue test kit for early detection:

More reading on Tests for Dengue:

  • Dengue Fever – no dang fun | The Guide Hog – This is the (insert string of expletives here) type of mosquito that infected me with Dengue Fever and made the last two weeks so miserable. Check out the World Health Organization fact sheet on dengue for lots of fascinating facts, like these: The Aedes aegypti mosquito lives in urban habitats and breeds mostly in man-made containers. aegypti is a daytime feeder; its peak biting periods are early in the morning and in the evening before dusk.
  • Thane Municipal Corporation calls for 2,500 more dengue … – THANE : The Thane Municipal Corporation (TMC) has issued for an additional 2,500 primary dengue test kits last week to deal with the rising dengue cases in the city. In addition to the 2,000 on-spot testing kits they supplied …
  • Dengue Diaries… | Woes of the burping butterfly – Tests still showed negative for Dengue and Malaria but his platelet count was dropping and dropping fast. The doctor wanted us to admit him immediately. So that’s what we did. He spent 4 days in the hospital. His dengue test …
  • trinituner.com • Really Feeling The LOSS AND PAIN Of our … – -It is a fact that in early stage the dengue test may come back negative and therefore blood test to determine … Powered by phpBB® Forum Software © phpBB Group
  • Case 20 (Dengue Fever – Case IV) | Association for … – 2nd Nov 2014- Fever 990F, feels better, parents were insisting on dengue test which was advised. Dengue- reactive, platelets- 1.36 lacs, WBC- 4700. Tuberculin 1M 1dose was given along with Eupatorium 1M tds. 4th Nov …
  • Neem-papaya juice passes dengue test – The Times of India – Siddha doctors said they were happy the government was now thinking of integrated medicine. via Neem-papaya juice passes dengue test – The Times of India. CHENNAI: After more than 37000 dengue cases, including 227 …
  • How it feels to get Dengue | YSPH 2015 Summer Internships – When I arrived at the hospital for work, I told my coworkers about my symptoms. I was promptly taken to the lab where I was given a free blood draw, complete blood count, and Dengue test – the perks of working in a hospital.

Dengue or Malaria?

Dengue or Malaria? Diagnosing  When You’re Not Sure

Discriminating Malaria from Dengue Fever in Endemic Areas: Clinical and Biological Criteria, Prognostic Score and Utility of the C-Reactive Protein: A Retrospective Matched-Pair Study in French Guiana

Is it dengue – or malaria?

This study aimed to establish a diagnostic algorithm for communities where dengue fever and malaria occur at some frequency in adults.

Background

Dengue and malaria are two major public health concerns in tropical settings. Although the pathogeneses of these two arthropod-borne diseases differ, their clinical and biological presentations are unspecific. During dengue epidemics, several hundred patients with fever and diffuse pain are weekly admitted at the emergency room. It is difficult to discriminate them from patients presenting malaria attacks. Furthermore, it may be impossible to provide a parasitological microscopic examination for all patients. This study aimed to establish a diagnostic algorithm for communities where dengue fever and malaria occur at some frequency in adults.

Methodology/Principal Findings

A sub-study using the control groups of a case-control study in French Guiana – originally designed to compare dengue and malaria co-infected cases to single infected cases – was performed between 2004 and 2010. In brief, 208 patients with malaria matched to 208 patients with dengue fever were compared in the present study. A predictive score of malaria versus dengue was established using .632 bootstrap procedures. Multivariate analysis showed that male gender, age, tachycardia, anemia, thrombocytopenia, and CRP>5 mg/l were independently associated with malaria. The predictive score using those variables had an AUC of 0.86 (95%CI: 0.82–0.89), and the CRP was the preponderant predictive factor. The sensitivity and specificity of CRP>5 mg/L to discriminate malaria from dengue were of 0.995 (95%CI: 0.991–1) and 0.35 (95%CI 0.32–0.39), respectively.

Conclusions/Significance

The clinical and biological score performed relatively well for discriminating cases of dengue versus malaria. Moreover, using only the CRP level turned to be a useful biomarker to discriminate feverish patients at low risk of malaria in an area where both infections exist. It would avoid more than 33% of unnecessary parasitological examinations with a very low risk of missing a malaria attack.

How to tell if you have dengue or malaria:

Genetically Modified Dengue Mosquitos

Genetically Modified Dengue Mosquitos are becoming big business. Nonprofits and corporations in Latin America are competing with different mosquito-altering technologies. It’s a competition between profits and public health. Eliminate Dengue, an Australian nonprofit  received $18 million from the U.S. government for citywide releases of mosquitoes infected with a bacteria that makes the species Aedes aegypti unable to transmit the two viruses in Rio de Janeiro and in a suburb of Medellin, Colombia.

This puts it ahead of for-profit efforts British corporation  Oxitec, which has field-tested GM mosquitoes in Brazil, the Cayman Islands, and Florida

Eliminate Dengue says that its females, infected with the bacterium Wolbachia, will eventually infect all mosquitoes in an area, replacing local mosquitoes with ones that cannot spread dengue and projects the cost of eliminating dengue virus as low as $1 a person, after releasing a million mosquitoes a year in an area of several square kilometers.

Oxitec aims to interrupt the spread of Zika and dengue in smaller areas using large-scale, weekly releases of millions of sterile male mosquitoes (in numbers 100 times greater than the normal males present in an area) that can’t reproduce and can’t spread their traits, a technology it describes as “self-limiting.” Brazilian officials testing Oxitec expect a cost of $7.50 a year, per person, to protect them.

Scott O’Neill, the entomologist who heads Eliminate Dengue, which has been funded heavily by the Bill and Melinda Gates Foundation, says, “The sterile male requires ongoing releases; that is why it’s associated with commercial groups, because there’s a revenue stream, like applying insecticides.”

 

Fil Randazzo, an official with the Gates Foundation, says, “I don’t believe that there is really a business model in a self-sustaining technology for public health,” Randazzo said. “I can’t see how there would be profit in releasing a few times and then you are done.”

Genetically Modified Dengue Mosquitos are a weapon of choice for some biologists fighting dengue fever. here’s why:

The level of fear mongering over the announcement of proposals to release genetically modified mosquitoes rather baffles me. For those who may not follow infectious disease news, there is an explosion of nasty mosquito borne viral infections in Puerto Rico and throughout Latin America—specifically Chikungunya, which I wrote about last week, and dengue.

These are not “rare” viruses, as some media would have you believe; they are on a rampage. And folks in Florida (and elsewhere in the southern US, especially) are naive to think that the mosquitoes will respect borders.

Blood feeding Aedes aegypti (close up view) - Oxitec

Here’s why mosquito controls are needed

It’s a shame the AP⁠ quoted a Key Haven resident rather than infectious diseases experts in their otherwise reasonable story: “If I knew that this was a real risk and lives could be saved, that would make sense. But there are no problems. Why are we trying to fix it? Why are we being used as the experiment, the guinea pigs, just to see what happens?” Were they trying to appeal to Sarah Palin fans?

People need to understand that mosquito borne illnesses are already present and increasing in the US. The Centers for Disease Control (CDC) has reported 11 locally transmitted cases of Chikungunya from Florida⁠ as of January 13, 2015, and 4,416 in Puerto Rico and the US Virgin Islands. Those are just the locally acquired cases, not those brought home from travel.

Dengue fever has been common in Puerto Rico, with more than 10,000 cases identified in a 2007 epidemic there.⁠

Similarly, there was a small outbreak in 2005 in Texas⁠ in which 16 of 25 cases had dengue hemorrhagic fever, which can be life threateningAntibodies to dengue, indicating previous infection, were found in 38% of the Brownsville⁠, TX residents tested. Dengue fever was identified originating in Florida in 2009 in Key West⁠, with 5% of residents tested showing evidence of recent dengue infection⁠. There has been a case in my small town, from a visit to the Keys, and one locally acquired in Long Island in 2013. Read more .

Here’s another well-written article on GM mosquitoes:

Humans are genetically modifying mosquitoes to fight a disease we helped create.

Dengue App

There’s an app for dengue: the dengue app that maps dengue

The Gates Foundation has been helping fund some dengue research. One of the side benefits of the research on dengue is a new app created by one of the researchers that lets everyone with a smart phone send in dengue reports that automatically use the phone’s GPS to target breeding areas, new cases of dengue, and so on. Very cool! Will people use it? It will still mean a lot of public education to make it part of people’s consciousness. Here’s the story:

Leah Katzelnick was all set for a career as an anthropologist until she contracted dengue fever. She was in hospital for a week with severe symptoms. It changed her life. She is now the only scientist focusing solely on dengue fever at the University of Cambridge, working in partnership with the National Institutes of Health to map the interaction between different strains of the virus, all enabled by a Gates Cambridge Scholarship.

Dengue outbreaks are common in many developing countries. Four billion people live in areas with the disease, although mortality is relatively low. There are 400m infections a year. Only 500,000 people develop severe infection symptoms and approximately 25,000 of these die. However, it places a huge burden on the health services of countries where there are major outbreaks. “Epidemics can swamp public health and intensive care services,” says Leah [2012]. “It creates fear even if there is a low likelihood of death and in many countries virtually everyone knows someone who has died from it, most of whom are children.”

For her PhD she has been working with both human and non-human primate sera.  Isolates from some of the main strains of the dengue virus are injected and Leah studies the immune sera to chart the complex inter-relationship between the four main strains of the virus. Dengue only causes mild infection in the non-human primates she works with.

Early years
Leah, from Madison, Wisconsin, was not sure what she wanted to study at university initially. She was interested in maths, music and history and was a keen participant in musical theatre at school. She was also interested in social justice issues and organised a teach-in about Darfur after getting to know the Sudanese husband of a local pastor.

At Williams College, where she did her undergraduate studies, she joined up with a friend who was interested in Uganda and the two organised several initiatives for eastern Africa, including book drives. She also joined Students for Social Justice and was involved in a hunger banquet and an alternative gift fair.

Leah had thought she would study pre-med and major in maths, but she found anthropology and English captured her imagination more. However, although she graduated with a major in anthropology she did pre-med throughout and became more and more interested in science, particularly virology.

In her second year she travelled to Nicaragua to hear people’s stories and try to understand the kind of issues they were facing. She had been studying a course on dilemmas around humanitarian interventions and how well-meaning interventions had failed due to a lack of understanding of the lives of those in receipt of aid.

In her third year she did a study abroad summer fellowship programme on international health to learn about different health systems and beliefs about health. It involved talking to people in NGOs about their aims and talking to people on the ground about how the NGOS were perceived. She travelled to Nicaragua again and lived with a family there who had good contacts with people working in international organisations. She started contacting different organisations and talking to people in the community.

Dengue
Then she contracted dengue fever and became very sick. “I was wandering Managua by myself talking to people asking them what the problems were with international organisations which seemed quite strange since I was a white North American. People were understandably quite suspicious of me and I came to a sad realisation that I might not be able to overcome that, read more…

Finally, an App that Allows you to report Dengue Breeding Sites

Each year 22,000 people die from dengue fever, many of them children. More than 100 million people contract it each year, almost entirely from carrier mosquitoes. About 2.5 billion people live in areas where dengue infection is a risk.

“The real problem with dengue is it occurs in an epidemic fashion, so it can paralyse healthcare systems when it comes through a big city, causing thousands of hospitalisations,” says Gavin Screaton, at Imperial College, London. The only prevention is mosquito repellent or spraying mosquito spawning areas.

Now a team of developers in Costa Rica have created a free app to allow the public to easily report the standing water that acts as mosquito hatcheries, and allow the government to quickly spray these areas with pesticides.

Costa Rica experienced more than 50,000 cases of dengue fever in 2013, twice as many as 2012, costing the country more than $800,000 in disability payments, and causing one death. This was despite the government investing $6m in spraying initiatives.

The health ministry worked with Geotecnologias, a local web-mapping company, to create an app to enable them to crowdsource mosquito hatcheries. The app, Reporte Criaderos Dengue, was built on the ArcGIS online mapping software that works in the cloud, donated by the creators ESRI.

Luis Araya, business manager at Geotecnologias, explains: “We have a tool that everyone can use to publish and show places where the mosquito can grow. The best part of the solution is that it is in real time, and that everyone can access the reports and info of the raised ticket.”

Users can log on at a suspected mosquito location and upload pictures, and any breeding classification information, as well as leave their contact details for more information. The app also includes a module explaining preventative measures, as well as the contact details of the health ministry and Geotecnologias. More

Dengue and Climate Change

The Connection Between Dengue and Climate Change

As these stories make clear, we’re paying another cost for climate change: the spread of tropical diseases. Here are some updates on dengue and climate change:

Dengue fever, the “world’s fastest growing vector-borne disease,” threatens some 2.5 billion people throughout the world, killing 20,000 each year. And climate change, according to a new report from U.N. University’s Institute for Water, Environment and Health, is going to put billions more at risk.

In simplest terms, as temperature increases, so, too, does a region’s risk, because warmer temperatures allow the dengue-carrying Aedes mosquito to thrive. Here, from the report, are maps showing how vulnerability changes along with temperature fluctuations throughout the year: more from Salon Magazine…

Risk of dengue increases due to climate change, city growth: research

LONDON (Thomson Reuters Foundation) – Large parts of Europe, West and Central Africa, and South America face the threat of outbreaks of the deadly dengue virus due to climate change and urbanization, according to the first-ever maps of dengue vulnerability published on Tuesday. Research by the United Nations University found dengue fever, more…

Dengue in Europe

Dengue Fever Alert in Southern Europe

New research fromOxford University has warned that southern European holiday destinations are ripe for colonisation by mosquitoes carrying dengue virus.
Tiger mosquitoes capable of carrying dengue and chikungunya viruses are spreading across the south of France, the Italian coastline and Spanish resorts like Barcelona, Benidorm and Malaga. Read more...

Dengue and dengue vectors in the WHO European region: past, present, and scenarios for the future

by Francis Schaffner, PhD, Dr Alexander Mathis,

After 55 years of absence, dengue has re-emerged in the WHO European region both as locally transmitted sporadic cases and as an outbreak in Madeira, driven by the introduction of people infected with the virus and the invasion of the vector mosquito species Aedes aegypti and Aedes albopictus. Models predict a further spread of A albopictus, particularly under climate change conditions. Dengue transmission models suggest a low risk in Europe, but these models too rarely include transmission by A albopictus (the main established vector). Further information gaps exist with regard to the Caucasus and central Asian countries of the WHO European region. Many European countries have implemented surveillance and control measures for invasive mosquitoes, but only a few include surveillance for dengue. As long as no dengue-specific prophylaxis or therapeutics are available, integrated vector management is the most sustainable control option. The rapid elimination of newly introduced A aegypti populations should be targeted in the European region, particularly in southern Europe and the Caucasus, where the species was present for decades until the 1950s. Read more…

Here’s a video about dengue in Europe:

 

 

Dengue Diagnosis Tools

Navy Medicine, Notre Dame Collaborate on New Tool to Diagnose Infectious Diseases, Dengue

We may soon see the emergence of dengue diagnosis tools that are rapid and accurate. They won’t replace the current lab tests but they will allow busy health workers to quickly tell the difference between a headache and a dengue infection. Here’s the story by Doris Ryan, Naval Medical Research Center Public Affairs

SILVER SPRING, Md. (NNS) — Researchers from the Naval Medical Research Center (NMRC) and the University of Notre Dame have agreed to collaborate on the engineering and application of a new field-deployable assay for the detection of infectious diseases, with the initial focus on the detection of dengue fever.

Currently, there are no U.S. Food and Drug Administration-approved rapid diagnostic tests to distinguish dengue virus infections from other febrile infectious diseases.

The University of Notre Dame initially approached NMRC in 2013 to explore collaborating on a portable detection assay. The effort was formalized in November with the signing of a Cooperative Research and Development Agreement and the team began working on designing a prototype. Once the prototype is completed and successfully tested, the team will use the technology to expand to other pathogens of military, national security and global health importance.

“This kind of assay could provide critical information and enable rapid response during an emerging outbreak of dengue,” said Dr. Shuenn-Jue Wu, principal investigator and senior scientist with the NMRC’s Viral and Rickettsial Diseases Department. “The recent Ebola outbreak in West Africa has shown there is a great need for additional tools that can help both military and civilian health workers track the spread of a disease over broad geographical areas. Current longterm military strategy is focused on USPACOM [U.S. Pacific Command] where dengue is endemic. The incidence and virulence of dengue is also increasing in USSOUTHCOM [U.S. Southern Command]. This assay could be a valuable tool because it will be relatively cheap, accurate, and used in areas without a lot of medical infrastructure.”

The initial clinical presentations of acute febrile illness from many infectious causes are the same: fever, chills, sweats, headaches, muscle pain, and fatigue. Clinical signs and symptoms are often not sufficient to make an accurate differential diagnosis of dengue. Rapidly identifying the pathogen causing an infection will also enable appropriate treatment and management of infected patients, as well as implementation of prevention and control efforts to protect the remainder of the force.

“Dengue-associated mortality can be reduced from 20 to 30 percent in severe cases, to less than 1 percent with appropriate fluid replacement and supportive care,” said Wu. “This is greatly facilitated by early diagnosis, because a positive laboratory test often alerts physicians to closely monitor patients for the warning symptoms associated with severe disease. Also, from a public health perspective, identification of dengue virus infections can geographically focus countermeasures such as targeted vector control.”

Once the prototype is available, the research team plans on working with NMRC’s subordinate commands in Peru and Cambodia to collect clinical samples and test the assay in a pilot clinical study. If successful they will reach out to an industry partner to transform the prototype into a final assay with supporting materials. Then the assay will be used in a future multicenter clinical study to meet Food and Drug Administration clearance requirements.

Wu went on to explain the goal is to develop a push-button technology that would allow the use of this assay in various geographical settings without the need for highly trained personnel. While the initial deployment of the device would target use by military personnel with extensive training in the laboratory, the researcher anticipates the longterm use of the assay by health care providers at clinics in resource limited settings.

“I feel it is imperative to continue exploring innovative technologies such as this collaboration with Notre Dame for use in low-resource settings to address the performance limitations of the traditional rapid diagnostic tests,” said Wu.

For more than 25 years, Wu has been involved in many aspects of dengue research and development including vaccines, pathogenesis and diagnostics at NMRC. Over the past 15 years she has focused on developing and evaluating field-deployable diagnostic assays for dengue fever and other military relevant infectious diseases. As a principal investigator she has coordinated with companies and overseas field sites and successfully completed international multicenter clinical trials of other dengue diagnostic devices aiming for FDA approval. For more news from Naval Medical Research Center, visit www.navy.mil/local/nmrc/.

Here’s a video on the current state of dengue diagnosis: