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:
retro-orbital eye pain,
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.
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.
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:
the Febrile Phase;
the Critical (Plasma Leak) Phase; and
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:
Was there Dengue bribery in Philippines? Questions hover over Asia’s first dengue vaccination program in Philippines.
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 buy viagra online canada 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…
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.”
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.
Can artemisia for dengue be as effective as it is for malaria? There’s a chance – admittedly slim – that artemisia might be effective in treating dengue fever. Last year, researcher Pierre Lutgen wrote : In the 1970s, there were only about nine countries where dengue fever existed but now the number is closer to 60. As of 2010 dengue fever is believed to infect 50 to 100 million people worldwide per year with 1/2 million life-threatening infections There is no cure and no real treatment.
A major dengue fever outbreak took place in Vanuatu in 2014, with several hundred cases. A female person living in Vanuata was infected by this virus. The infection was classified as dengue by clinical analysis in the hospital where she spent a week. She claims to have recovered after drinking Artemisia annua infusion (origin of the herb : Luxembourg). Subsequently several of her relatives suffered from the same symptoms and were all cured in a few days after tea A annua consumption. The Health Authorities confirm that these people were infected by the dengue virus. This is the first in vivo report on the efficiency of Artemisia annua against dengue. It needs of course to be confirmed by clinical trials in accordance with the WHO protocol.
So some clever scientists decided to try artemisia for dengue in the lab. Here’s what they found:
Malaria and dengue are the two most important vector-borne human diseases caused by mosquito vectors Anopheles stephensi and Aedes aegypti, respectively. Of the various strategies adopted for eliminating these diseases, controlling of vectors through herbs has been reckoned as one of the important measures for preventing their resurgence. Artemisia annua leaf chloroform extract when tried against larvae of A. stephensi and A. aegypti has shown a strong larvicidal activity against both of these vectors, their respective LC50 and LC90 values being 0.84 and 4.91 ppm for A. stephensi and 0.67 and 5.84 ppm for A. aegypti. The crude extract when separated through column chromatography using petroleum ether-ethyl acetate gradient (0–100 %) yielded 76 fractions which were pooled into three different active fractions A, B and C on the basis of same or nearly similar R f values. The aforesaid pooled fractions when assayed against the larvae of A. stephensi too reported a strong larvicidal activity. The respective marker compound purified from the individual fractions A, B and C, were Artemisinin, Arteannuin B and Artemisinic acid, as confirmed and characterized through FT-IR and NMR. This is our first report of strong mortality of A. annua leaf chloroform extract against vectors of two deadly diseases. This technology can be scaled up for commercial exploitation.
Author(s): Gaurav Sharma , Himanshi Kapoor , Madhu Chopra , Kaushal Kumar & Veena Agrawa
Reference: Parasitology Research, January 2014, Volume 113, Issue 1, pp 197-209
Access: Click here to go to the Journal
Contact email: email@example.com
So the news so far is good on artemisia and dengue!
For more on artemesia and its modern history, check out this article in Forbes. And watch this video to see where in the dengue virus lifecycle artemisia might be useful:
It’s a global geographic database of human dengue virus occurrence that researchers produced to generate a global risk map and associated burden estimates. Herein we present the database, which comprises occurrence data linked to point or polygon locations, derived from peer-reviewed literature and case reports as well as informal online sources. Entries date from 1960 to 2012. We describe all data collection processes in full, as well as geo-positioning, database management and quality-control procedures. This is the most comprehensive database of confirmed human dengue infection to-date, consisting of 8,309 geo-positioned occurrences in total.
The quality of reporting of dengue virus infection is inconsistent by country and by region and is often biased by difficulties in diagnosis, limited resources for diagnostic testing and the varying reporting capacities of national health systems. Furthermore, active surveillance of dengue infection, which can often be asymptomatic, is rare, so it is difficult to gauge the limits and intensity of transmission in a consistent manner across the world using standard reported case data. In order to address these biases, this database focuses on occurrence rather than incidence of dengue virus infection which allows it to inform global risk models more accurately. The final database described here consists of records of known occurrences of dengue virus infection globally, each identified by its unique geographical location and the year in which it occurred between 1960 and 2012. Sources of information include published literature, case reports and informal online sources, described in detail in our methods section.
With this database, it is possible to model the probability of occurrence of dengue transmission with a high degree of spatial resolution, for example as in Bhatt et al.1, the first project to make use of it in its final form. Bhatt et al. derived the global probability of occurrence of dengue over long-term average conditions at a 5 km×5 km resolution using the database described here as well as a suite of environmental covariates described in the supplementary information to that paper. This final map was also used to support a project examining risk for dengue during the 2014 World Cup in Brazil2and the database was also updated to contain type-specific information and re-summarised by province in a paper by Messina et al.3 which examines the spread of each of the four dengue virus types. Because the locations of dengue occurrence are recorded at the finest level of detail possible (i.e., points when the exact location was known or else polygons for administrative units when this was the best information available), the database may be used for dengue mapping and modelling at any spatial resolution required, with the only limiting factor being the resolution of the modelling covariates or the specific aims of the user.
It should be noted that we did not discriminate studies or reports based upon the clinical outcome of the dengue infections they reported; this information was not consistently reported across all of the varied sources and we aimed to be comprehensive in our inclusion of all known locations of dengue infection. Thus, while we included asymptomatic infections reported in the few existing prospective population-based seroepidemiological studies (i.e., cohort studies, which are the only type of study capable of detecting and measuring this type of infection), they were not distinguished from occurrences of the disease derived from symptomatic hospital-reported cases.
All data collection processes are described in full here, as well as the geo-positioning, quality-control and database-management procedures. The database’s construction from many different sources of information makes it the best currently available standardised data available on global dengue transmission. The result is the most comprehensive database of confirmed human dengue infection to-date, consisting of 8,309 geo-positioned occurrences in total worldwide. The database is not necessarily confined to use for global analyses, as it contains enough detailed information for many parts of the world to carry out modelling at a regional or even sub-national scale, with regions and countries specified in addition to the specific location of every record in order to facilitate sub-setting of the database for the user’s needs. Read more here about the Global Guide to Dengue Occurrence.
Dengue in Brazil has been endemic for centuries. Here’s an update on this season’s Dengue in Brazil:
BRASILIA, May 4 (Xinhua) — Brazil saw 746,000 cases of Dengue fever between Jan. 1 and April 18 this year, an increase of 234 percent from the same period last year, said the Brazilian Health Ministry on Monday.
However, compared to the same time span in 2013, when 1.4 million cases were reported, the figure is 48 percent lower.
In the first 15 weeks of 2015, 229 Dengue fever patients were confirmed dead. This is a 45 percent rise from the same period last year and a 39.6 percent drop from the same period in 2013.
The states which saw the biggest number of deaths were Sao Paulo, with 169 deaths, Goias, with 15 and Parana and Minas Gerais with eight deaths each.
Dengue fever, a viral infection found throughout 110 countries, is spread by mosquitos in tropical climate, causing flu-like symptoms such as headache, fever and joint pain. English.news.cn 2015-05-05 11:37:26
SÃO PAULO, Brazil — In March, I spent 10 days in bed, mostly moaning and eating large quantities of pears — the only food I found remotely appetizing. I was one of the roughly 500,000 Brazilians infected with dengue fever in the first three months of 2015, over half of them in the state of São Paulo, according to the Ministry of Health. Here, a mosquito called Aedes aegypti spreads the tropical disease, which, in extreme cases, can lead to internal bleeding, organ failure and death. In those three months, 132 Brazilians died of dengue fever — more than one a day.
I had probably been infected at home, despite my maximum-security domestic measures.
I cover my legs with insect repellent. All of my windows and doors are equipped with mosquito nets, but I still keep two electric mosquito swatters inside the house. The swatters are shaped like tennis rackets and deliver an electric shock strong enough to kill bugs. One stays in the bedroom, where I work, and the other in the living room, where I watch movies while violently hitting insects as if for sport.
Despite the precautions, the bugs keep biting me without mercy. That first week of March was no different from the others, spent entirely working and roasting mosquitoes at home.
Then, on Sunday, I woke up tired and feverish, with a temperature of 102 degrees. I was exhausted and had an annoying headache. But no sore throat, no cough and no viscous substances running through my nose. So I reached Dr. Google and learned that a sudden fever not accompanied by typical flu symptoms is evidence of dengue (or chikungunya, another disease brought on by the same striped mosquito).
I promptly recalled all the public awareness ads on TV and in magazines urging people to seek immediate medical attention if they suspect they have dengue, and I felt almost a civic duty to report to a hospital. There is no cure for dengue, but timely treatment lowers the death rate below 1 percent. Also, I was taking a prescription anti-inflammatory drug called meloxicam to relieve neck pain and I needed to know, for sure, if I should keep taking it. (Every Brazilian knows that dengue patients shouldn’t take aspirin because it can aggravate bleeding.)
I spent more than three hours in the waiting room of a private hospital covered by my health insurance before the doctor could take a look at my blood count. He then said it was fine. He proceeded to tell me that specific tests for dengue fever could be performed only six days after the first symptoms. “Yes, it could be dengue,” he told me. “But honestly it could be anything.” He said it was fine to keep taking the meloxicam, and sent me home with a prescription to reduce my fever.
I was relieved, until I resorted again to Dr. Google. Apparently it is possible to test for dengue after the first day of fever, before antibodies appear. The NS1 antigen test is cheap and reliable. I also learned that it was definitely not advisable to continue to take meloxicam because, like aspirin, it could also raise the risk of bleeding; my orthopedist called the next day to forbid me from doing it.
I assume the doctor I saw at the hospital didn’t report me as having dengue, so I guess I’m not included in the Ministry of Health statistics. It took three weeks for me to find out for sure it was dengue, after a test… read more at The New York Times.
Vanessa Barbara is a columnist for the Brazilian newspaper O Estado de São Paulo and the editor of the literary website A Hortaliça.
Dengue in China is Real and Health Workers are on the Case!
Kaohsiung residents will be able to turn pests into positivity, as the city plans to reward those who have caught the most mosquitoes by Saturday.
In a campaign that started Wednesday, city health authorities have asked the public to collect as many mosquitoes as possible and tally them on Saturday in a bid to remove the principal transmitter of the disease. Mosquitoes are carriers of dengue fever and have contributed to the outbreak in the southern Taiwan city. The pests being targeted are Aedes aegypti and Aedes albopictus, also known as the yellow fever mosquito and the tiger mosquito, respectively.
According to the city’s Department of Health, which is organizing the campaign, the winner will be the person who has caught the largest number of those two types of mosquitoes — regardless of their state of being (mature or in larval form), alive or dead. “Instead of fining people who fail to remove standing water and other breeding sites around their homes, we think this program could raise greater community participation,” said Ho Hui-ping, chief of the section in the Health Department responsible for the campaign. The No. 1 mosquito keeper will be rewarded NT$3,000 (US$100), while the top 10 contestants will each be given free bug spray and mosquito nets, according to Ho.
To be eligible for the prizes, participants must bring their catches to Alley 161, Lichi Street in Kaohsiung between 8am and 10:30am Saturday, she said. The results will be announced after city staffers tally the number of mosquitoes turned in. That will be followed by a community cleaning event, according to the department. The competition is among the city’s more unconventional approaches to clear it of the mosquitoes amid an outbreak of over 7,500 cases of dengue fever by the end of October, including five more severe hemorrhagic dengue fever cases. Another idea under consideration is to use sea water to flush out the city’s drainage system and thus destroy mosquito breeding grounds, the city government said. Dengue fever is an infectious tropical disease spread by mosquitoes. The symptoms include fever, headache, muscle and joint pain, and skin rash. In a small proportion of cases, the disease can develop into hemorrhagic dengue fever, which can be fatal.
Dengue in China is 900 years Old.
Now Chinese health officials are bringing to bear modern weapons of mass detection. An outbreak detection and response system, using time series moving percentile method based on historical data, in China has been used for identifying dengue fever outbreaks since 2008. For dengue fever outbreaks reported from 2009 to 2012, this system achieved a sensitivity of 100%, a specificity of 99.8% and a median time to detection of 3 days, which indicated that the system was a useful decision tool for dengue fever control and risk-management programs in China.
Detecting infectious disease outbreaks quickly is crucial for timely implementation of control measures, thereby minimizing morbidity and mortality. To automatically identify aberrations in disease incidence data at an early stage, some countries have established infectious disease surveillance and outbreak detection systems, such as the Early Aberration Reporting System (EARS) of the US Centre for Disease Control and Prevention , the Real-time Outbreak and Disease Surveillance (RODS) system of the University of Pittsburgh , the Electronic Surveillance System for the Early Notification of Community-Based Epidemics (ESSENCE) in the USA , and SurvNet@RKI in Germany .
Dengue fever (DF) is one of the world’s most important vector-borne diseases, with cases reported from more than 100 countries in Africa, America, Southeast Asia, the Western Pacific and Europe. The World Health Organization estimates that DF affects over 50 million people annually . In 1978, DF re-emerged in Guangdong province, China, after having disappeared from the country for more than 30 years . From 1978 to 2012 more than 650,000 cases of DF, and hundreds of deaths, were documented in China. DF epidemics had spread from Guangdong, Hainan and Guangxi provinces in the southern coastal regions to some relatively northern regions including Fujian and Zhejiang provinces . It has been suggested that establishing an early outbreak detection system is one of the prerequisites for adequate preparedness and responses to DF epidemics , which can enable better engagement of the community in prevention and control activities, thereby reducing DF transmission and improving clinical outcomes.\To facilitate early detection of infectious disease outbreaks, the Chinese Centre for Disease Control and Prevention (China CDC) has developed the China Infectious Disease Automated-alert and Response System (CIDARS), implemented since April 2008 . CIDARS automatically conduct the aberration detection from the reported data in the web-based Nationwide Notifiable Infectious Diseases Reporting Information System (NIDRIS). This was established in 2004 and is the largest direct infectious disease reporting system in the world, covering all general hospitals in the prefectures, and all hospitals in the counties and townships in China . CIDARS has been operating in China for more than four years. This study aims to provide a preliminarily prospective evaluation of the performance of CIDARS for DF outbreak detection during the initial phase of real-world implementation nationwide. Read more about Dengue in China at PLOS1
1,145 Dengue Fever Cases in Guangdong
A total of 1,145 dengue fever cases have been confirmed in South China’s Guangdong province, with 31 people in critical condition, according to a statement released by local health authorities.Of the cases, 90% are confirmed in Guangzhou. There have been no deaths reported, the statement said.Zhang Yonghui, director of the Guangdong Provincial Center for Disease Control and Prevention, appealed to all citizens to take self-protective measures against mosquitoes and to take steps to eradicate them so as to the disease.Dengue fever is a mosquito-borne, potentially fatal disease that affects between 50 and 100 million people in tropical and subtropical regions every year, causing fever, muscle and joint aches.According to figures from the center, the mosquito population is five times the normal level due to high temperatures and rainy weather in Guangdong.September to November will see a peak in cases and effort is needed from everyone in the province to help with prevention efforts, Zhang said. (Xinhua).
Dengue Fever Outbreaks Come to China
Though much of the world is focused on the Ebola virus, pockets of Asia are struggling with record outbreaks of a mosquito-borne infectious disease called dengue fever, which has no specific drug treatment. As the WSJ’s Shirley S. Wang reports:
Guangdong Province is facing its largest outbreak of the virus in more than 20 years. There have been more than 44,000 confirmed cases there, with more than 15,500 people hospitalized and six deaths as of Nov. 12, according to the Provincial Health and Family Planning Commission.
On Nov. 3, the U.S. Centers for Disease Control and Prevention warned travelers to the region about the outbreak, advising them to prevent mosquito bites.
The Taiwanese city of Kaohsiung, with more than 9,000 cases, is battling its largest-ever outbreak of laboratory-confirmed infections. In Hong Kong on Nov. 7, officials confirmed a third case of locally acquired dengue, after last month discovering its first in four years. Earlier this fall, Japan faced its first outbreak in 70 years. While the virus can’t be spread directly from person to person, a mosquito that has bitten an infected human can transmit the disease to others.
Within a few days of the first locally acquired case of dengue in Hong Kong, which is known for its meticulous public-health and mosquito-control practices, officials had questioned about 300 people in the vicinity of the place where the patient was believed to have contracted the illness and other sites he had frequented, and held two meetings to educate the public about the virus. Dengue fever cases world-wide have climbed dramatically since the 1960s, with some 50 million people infected annually. Some 500,000 are estimated to contract more-severe dengue that requires hospitalization, leading to about 22,000 deaths each year, according to the World Health Organization. Read the full story on WSJ.com.
Dengue fever: a new challenge for China?
Responsible Editor: Peter Byass, Umeå University, Sweden.
Dengue outbreaks in the Guangdong province reached epidemic proportions in the last quarter of 2014. According to the Guangdong provincial health and family planning commission (1), as of October 27, the total number of dengue fever cases with clinical and laboratory diagnoses reached 41,155. Geographically, more than 80% of dengue cases were reported in Guangzhou City (the capital of the Guangdong province) and its neighbouring prefectures—showing the susceptibility to dengue of areas with dense populations.
Although dengue, one of the most strongly emerging, neglected tropical diseases worldwide and presently without widely available drugs or vaccines, has a geographical distribution in South China (2), this outbreak of dengue fever was the first in South China for almost 20 years. For example, only 120 cases of dengue were reported in China during the year 2011 (2). Of note, the number of imported cases of dengue is on the rise. Moreover, a previous study using spatial scan cluster analyses suggested that counties around Guangzhou City and Chaoshan Region were at increased risk for dengue fever (3). The recent increase in cases could be due to imported dengue cases combined with climatic change (4). In 2009, dengue virus serotype 3 (DENV-3) was first detected in Guangzhou and another isolated strain belonging to genotype II was identified (5). A later investigation reported that three imported cases separately travelled back from Vietnam, India, and Tanzania. The Tanzanian case was confirmed to be the index for the dengue outbreak in Guangdong in 2010 (6). Global climate change has been recognised as a contributor to many infectious diseases (7). Weather factors have been associated with dengue, for example, a previous study used time series Poisson regression analysis on the monthly weather data from Guangzhou and pointed out that minimum temperature and minimum humidity, at a lag of 1 month, were positively associated with dengue incidence in the subtropical city of Guangzhou (8). Guangzhou is close to the tropics and is thus sensitive to the effects of climate change, so an outbreak was probably only a matter of time. China needs to tackle the increase in dengue. The lessons learnt…more…
China Tests Wolbachia-Infected Mosquitos.
Yang Zhicong, deputy director of Guangzhou’s centre for disease control and prevention, and his colleagues have released mosquitoes infected with wolbachia bacteria, which make the males sterile and limit the insects’ ability to carry dengue.
Last year’s outbreak has helped persuade residents to embrace the pilot scheme, as has Xi’s willingness to plunge his hand into mosquito pots to prove that the males they are releasing do not bite. And while the Chinese government has not approved the release of genetically modified creatures, it accepted this trial because wolbachia occurs naturally in many insects.
In the first phase, the team aims to reduce the mosquito population, as sterile males breed with wild females. In the second, wolbachia-infected females – “very few”, Xi promised – will be released to replace the wild, dengue-transmitting population, so mosquitoes from other areas face competition if they try to move in.
“The final outcome in the release site will be that, firstly, there will be few mosquitoes biting people, and secondly, these mosquitoes are resistant to dengue virus,” he predicted.
Dengue has been overlooked by governments and aid donors, said Dr Raman Velayudhan, of the World Health Organisation’s department of control for neglected tropical diseases.
“In terms of the number of people who fall sick, dengue and malaria are very similar. Dengue affects 128 countries; malaria 97. The neglect I think comes because dengue doesn’t kill as many people,” he said. Read more at The Guardian.
Dengue in China is Endemic
Dengue has been known in China long before it was identified anywhere else. Since the first known description of dengue (and its treatment) date from China in the 11th. century, the Chinese have been hard at work controlling and preventing it.
The Lancet Seminar1 by Maria Guzman and Eva Harris on dengue regarded the burden of dengue in China as unknown. However, dengue fever is a notifiable disease in China, and all cases of dengue fever were diagnosed according to the unified diagnostic criteria issued by the National Health and Family Planning Commission, which includes definitions of clinically diagnosed and laboratory-confirmed cases. From 1978 to 2008, a total of 655 324 cases were reported in mainland China, resulting in 610 deaths.2 According to China National Notifiable Disease Surveillance System, from 2009 to 2014, the range of incidence was 0·0091–3·4581 per 100 000 people, and a total of 52 749 cases of dengue fever and six deaths were notified (figure). Because dengue is an emerging disease in China, possible cases are traced by active field investigation when outbreaks occur in the community. Thus, dengue surveillance involves both passive and active case detection. Further study should focus on analysis of prevalence and assessment of relations between seroprevalence and incidence.
Incidence and cases notified of dengue fever (2009–14)
In 2014, a series of dengue fever outbreaks occurred in Guangdong, Yunnan, Fujian, and Guangxi. These outbreaks pose a substantial socioeconomic burden. Additionally, these outbreaks showed new epidemic trends for dengue fever in Guangdong. Hui and colleagues3 showed that DENV-2 strains circulating in Guangdong have been stable since their introduction in the 2000s—which challenged the view that dengue fever is an imported epidemic disease. We declare no competing interests. We thank the National Basic Research Programme of China and the National Natural Science Foundation of China for support.
Dengue fever can damage eyesight. That’s the conclusion of ophthalmologists in Brazil, where dengue is endemic. Clinicians at the Penido Burnier Institute, Leoncio Queiroz Neto. Brazil, warn that delay in seeking treatment can cause serious eye disorders that often go unnoticed. Red spots on the skin, fever, pain in the joints, eyes and muscles are the first warning signs of the disease.
The risk of eye damage is greater when you’re exposed to two different types of the (four strains) of the virus. This reinfection makes you more vulnerable to bleeding in the retina, the layer of nerve cells at the back of the eye that captures and transmits images to the brain. Even ‘ordinary’ Dengue, considered less dangerous, can affect the eye lining, choroid and retina. So consult an ophthalmologist within 7 days of your diagnosis. The main changes in the blood are:
Decrease in white blood cells and lymphocytes responsible for defending the body.
Fall in your platelet count (platelets are responsible for clotting).
This permits vascular occlusion (blocking), precipitated by antibody deposit on the inner walls of the arteries and vessels. There is increased risk of intraocular bleeding.
Scientists think that the collapse in the number of platelets increases the risk of subconjunctival or intraocular bleeding – even among those who have never been infected with Dengue before.
Only subconjunctival hemorrhage changes the appearance of your eye, leaving the sclera (white part) red and congested with blood – your eye looks as though something has hit it. This symptom is more common among children.
Despite its alarming appearance, this is not a serious problem and disappears in weeks without medication.
In case of eye pain or blurred vision, the recommendation is to consult an ophthalmologist immediately!
Vascular occlusion (thrombosis) following the deposit of antibodies in the artery walls can leave blurred vision. The diagnosis is made by a fundus examination. When vascular changes are detected the condition can be treated with laser applications to prevent bleeding. In case of bleeding, the ophthalmologist says vitrectomy is indicated: a surgical procedure done with micro incisions to eliminate the bleeding that causes irreversible blindness if it reaches the macula (the central part of the retina).
1 in 4 cases of dengue occur in children
smoking doubles the risk of intraocular hemorrhage because cigarette chemicals cause vascular obstruction.
Patients with diabetes and high cholesterol that cause atherosclerosis also increase the risk.
I spent an afternoon recently with Mr. Suthep, who oversees dengue control in Chiang Mai province. He’s responsible for protecting 1,600,000 people in Northern Thailand from dengue infections. Since dengue is endemic in Thailand, the Thai Government in Bangkok monitors his progress closely.
What kind of person runs a dengue control program? Well, Mr. Suthep is a medical entomologist – someone who studies insect disease vectors. He’s where public health policy meets the public. He’s the last link in the chain between Parliament and thousands of villages.
It was mid-winter when we talked: Thailand’s November–May dry season. That’s Mr. Suthep’s peak season because that’s when he trains village health volunteers and equips them for the coming rains and the inevitable mosquito explosion.
To show how hard it is to run a good dengue control program, here’s a WHO video of one country’s successful efforts to control the little pest:
Some research in nearby Cambodia had caught his eye:
When people came into the Cambodian hospital with symptoms of dengue fever during the summers of 2012 and 2013, the researchers followed them home and checked to see if anyone living within a 200 meter radius of them was harboring an asymptomatic dengue infection. If so, after obtaining written informed consent, the researchers allowed twenty-five starved female mosquitoes to gorge on their legs. The participants were mostly kids around ten years old; their guardian provided the consent.
The mosquitoes set loose upon them were reared in a lab and did not carry dengue, Japanese encephalitis, or chikungunya viruses. The kids got antihistamine cream on their bites to deal with the itching. Many of the mosquitos ended up carrying dengue.
Humans were infectious to mosquitoes from two days before symptoms appeared until six days after the onset of illness. Despite the fact that asymptomatic people have lower levels of virus, they were more infectious—their blood infected a higher proportion of mosquitoes, and those mosquitoes had a higher viral load than mosquitoes that fed on symptomatic dengue carriers. Perhaps the immune response mounted by the people made sick by dengue reduces their ability to infect mosquitoes with the virus.
People who are infected with dengue but are asymptomatic typically go about their daily business as normal and have many more opportunities to be bitten by and infect mosquitoes than those languishing with symptoms at home or in the hospital.
The fact that disease transmission can occur before disease symptoms manifest means that epidemics can rise rapidly. This finding thus has public health and policy implications in terms of how quickly future epidemics will be recognized and managed, and it suggests that infection, not disease, should be monitored in vaccine development and other preventative strategies.