Global & Disaster Medicine

Archive for the ‘Dengue’ Category

Dengue fever – Burkina Faso

WHO

Dengue fever – Burkina Faso

Disease outbreak news
6 November 2017

Burkina Faso has been experiencing an epidemic of dengue fever since week 31 of 2017 (week ending on 6 August). WHO officially declared the outbreak on 28 September 2017. Unlike the previous occurrence in 2016, several serotypes of dengue have been detected and the number of cases quickly exceeded past seasonal outbreaks.

As of 27 October 2017, a total of 6 699 (suspected, probable or confirmed) cases and 13 deaths (CFR= 0.2%) were reported throughout the country. Of the total cases reported, 4 428 (66%) were probable, with a positive result for dengue by rapid diagnostic test (RDT), of 241 samples referred for PCR testing at the Viral Haemorrhagic fever (VHF) reference lab of the Centre Muraz, Bobo-Dioulasso, 141 (59%) were confirmed cases by positive result. Further characterization of 72 samples has identified three dengue virus serotypes: DENV-2 (N=58), DENV-3 (N=12) and DENV-1 (N=2). Cases are currently reported in 12 of the country’s 13 health regions, with 64% of cases reported in the central region, particularly in the city of Ouagadougou.

Public health response

  • The National Epidemic Management Committee has been activated to coordinate response activities.
  • Strengthening the epidemiological surveillance, and putting in place an Early Warning System that provides daily notification of cases in Ouagadougou and weekly in the other provinces.
  • Provision of free medical care and treatment for severe cases in all hospitals (Regional and District hospitals). 5 000 RDTs distributed to reference health centers.
  • Development and dissemination of a national dengue clinical management algorithm.
  • Delivery and dissemination of key awareness and prevention measures through radio and television programs.
  • Periodic shipment of samples to the VHF laboratory of the Centre Muraz, Bobo-Dioulasso.
  • Implementation of intensive vector control interventions targeting larva and adult mosquitoes through.
    • Elimination of mosquito breeding sites which was carried out by community volunteers in Ouagadougou;
    • Distribution of 1 500 Long Lasting Insecticidal Nets (LLINs) to hospitals;
    • Ongoing in-door spraying to control adult mosquitoes at the household level.

WHO risk assessment

This outbreak is occurring in the context of an improved but still limited dengue surveillance system in Burkina Faso. The weekly case incidence has been on the rise since the detection of the outbreak in week 31 and is likely underestimated. The epidemic has already spread to twelve of the country’s thirteen health zones and many public health facilities do not have access to dengue fever diagnostics (RDTs).

Burkina Faso experienced an outbreak of dengue in 2016 which was caused by DENV-2. In the current outbreak, three serotypes were identified: DENV-1, DENV-2, and DENV-3. This could lead to the occurrence of more severe cases, which may not be captured by the surveillance system due to under-reporting from private clinics and healthcare centers in peripheral districts.

The existence of multiple mosquito breeding sites after the rainy season may favor the continued presence of mosquito populations in the affected communities In particular, the peripheral districts of cities in Burkina Faso are characterized by poor sanitation and the accumulation of rubbish dump sites, tires and used containers which provide productive breeding sites for Aedes aegypti mosquitoes (the primary vector for dengue).

WHO advice

WHO recommends adequate and timely case management dengue cases. Surveillance should be strengthened within all affected health zones. Key public health communication messages should be provided. Integrated Vector Management (IVM) activities should be enhanced to remove potential breeding sites, reduce vector populations and minimize individual exposures. This should include both vector control strategies (i.e. environmental management, and chemical and biological control measures), as well as strategies to protect individuals and households. For further information, see:

WHO recommends that countries should consider the introduction of the dengue vaccine CYD-TDV only in geographic settings (national or subnational) where epidemiological data indicate a high burden of disease. Complete recommendations may be found in the WHO position paper on dengue vaccines:

WHO advises against any restriction on travel and trade to Burkina Faso or the affected district based on the available information.


CDC recommendations to healthcare providers treating patients in Puerto Rico and USVI, as well as those treating patients in the continental US who recently traveled in hurricane-affected areas during the period of September 2017 – March 2018.

CDC

Advice for Providers Treating Patients in or Recently Returned from Hurricane-Affected Areas, Including Puerto Rico and US Virgin Islands

Distributed via the CDC Health Alert Network
October 24, 2017, 1330 ET (1:30 PM ET)
CDCHAN-00408

Summary
The Centers for Disease Control and Prevention (CDC) is working with federal, state, territorial, and local agencies and global health partners in response to recent hurricanes. CDC is aware of media reports and anecdotal accounts of various infectious diseases in hurricane-affected areas, including Puerto Rico and the US Virgin Islands (USVI). Because of compromised drinking water and decreased access to safe water, food, and shelter, the conditions for outbreaks of infectious diseases exist.

The purpose of this HAN advisory is to remind clinicians assessing patients currently in or recently returned from hurricane-affected areas to be vigilant in looking for certain infectious diseases, including leptospirosis, dengue, hepatitis A, typhoid fever, vibriosis, and influenza. Additionally, this Advisory provides guidance to state and territorial health departments on enhanced disease reporting.

 

Background
Hurricanes Irma and Maria made landfall in Puerto Rico and USVI in September 2017, causing widespread flooding and devastation. Natural hazards associated with the storms continue to affect many areas. Infectious disease outbreaks of diarrheal and respiratory illnesses can occur when access to safe water and sewage systems are disrupted and personal hygiene is difficult to maintain. Additionally, vector borne diseases can occur due to increased mosquito breeding in standing water; both Puerto Rico and USVI are at risk for outbreaks of dengue, Zika, and chikungunya.

Health care providers and public health practitioners should be aware that post-hurricane environmental conditions may pose an increased risk for the spread of infectious diseases among patients in or recently returned from hurricane-affected areas; including leptospirosis, dengue, hepatitis A, typhoid fever, vibriosis, and influenza. The period of heightened risk may last through March 2018, based on current predictions of full restoration of power and safe water systems in Puerto Rico and USVI.

In addition, providers in health care facilities that have experienced water damage or contaminated water systems should be aware of the potential for increased risk of infections in those facilities due to invasive fungi, nontuberculous Mycobacterium species, Legionella species, and other Gram-negative bacteria associated with water (e.g., Pseudomonas), especially among critically ill or immunocompromised patients.

Cholera has not occurred in Puerto Rico or USVI in many decades and is not expected to occur post-hurricane.

 

Recommendations

These recommendations apply to healthcare providers treating patients in Puerto Rico and USVI, as well as those treating patients in the continental US who recently traveled in hurricane-affected areas (e.g., within the past 4 weeks), during the period of September 2017 – March 2018.

  • Health care providers and public health practitioners in hurricane-affected areas should look for community and healthcare-associated infectious diseases.
  • Health care providers in the continental US are encouraged to ask patients about recent travel (e.g., within the past 4 weeks) to hurricane-affected areas.
  • All healthcare providers should consider less common infectious disease etiologies in patients presenting with evidence of acute respiratory illness, gastroenteritis, renal or hepatic failure, wound infection, or other febrile illness. Some particularly important infectious diseases to consider include leptospirosis, dengue, hepatitis A, typhoid fever, vibriosis, and influenza.
  • In the context of limited laboratory resources in hurricane-affected areas, health care providers should contact their territorial or state health department if they need assistance with ordering specific diagnostic tests.
  • For certain conditions, such as leptospirosis, empiric therapy should be considered pending results of diagnostic tests— treatment for leptospirosis is most effective when initiated early in the disease process. Providers can contact their territorial or state health department or CDC for consultation.
  • Local health care providers are strongly encouraged to report patients for whom there is a high level of suspicion for leptospirosis, dengue, hepatitis A, typhoid, and vibriosis to their local health authorities, while awaiting laboratory confirmation.
  • Confirmed cases of leptospirosis, dengue, hepatitis A, typhoid fever, and vibriosis should be immediately reported to the territorial or state health department to facilitate public health investigation and, as appropriate, mitigate the risk of local transmission. While some of these conditions are not listed as reportable conditions in all states, they are conditions of public health importance and should be reported.

 

For More Information


Dengue: New Dengue Case Definitions (2009)

CDC

Dengue without Warning Signs expanded

Fever and two of the following:

Nausea, vomiting


Rash


Aches and pains


Leukopenia


Positive tourniquet test

 

Dengue with Warning Signs** collapsed

Dengue as defined above with any of the following:

Abdominal pain or tenderness


Persistent vomiting


Clinical fluid accumulation (ascites, pleural effusion)


Mucosal bleeding


Lethargy, restlessness


Liver enlargement >2 cm


Laboratory: increase in HCT concurrent with rapid decrease in platelet count

**requires strict observation and medical intervention

 

Severe Dengue collapsed

Dengue with at least one of the following criteria:
Severe Plasma Leakage leading to:

– Shock (DSS)
– Fluid accumulation with respiratory distress


Severe Bleeding as evaluated by clinician


Severe organ involvement

– Liver: AST or ALT ≥ 1000

– CNS: impaired consciousness

– Failure of heart and other organs

 

 

 


CDC: Dengue Management Guide (Clinical management tools for health care providers)

CDC-Dengue Management Guide

DengueDHF-Information-for-Health-Care-Practitioners_2009

Life cycle of mosquitos in a diagram

Life cycle of mosquitos in jars

 

 


Surge of Dengue cases in Myanmar (Burma): More than 4500 cases

Myanmar

Date: Thu 31 Aug 2017 10:31
Source: Eleven Media [in Myanmar, trans. Mod.YMA, edited]
<http://news-eleven.com/news/8267>

“The dengue cases reported in Yangon Region during 2017 are higher than
those of 2016. During the 1st 4 months, the incidence increased as
high as 4 times [than that of 2016].

At present, there are more than 4500 cases and 32 deaths of dengue
infection. Larvae control activities are being carried out in the
areas with high incidence. The highest number of cases are found in
Hlaingtharya, 4 areas in Dagon Myothit, Dala, Thaketa, Mayangone, and
Hlaing Townships as usual, according to the Regional Public Health
Department in Yangon Region.”

[Byline: Ei Thinzar Kyaw]

Global Map of Dengue Fever Source:  CDC

 


An adult Aedes aegypti mosquito, the species responsible for the majority of human Zika virus cases, has been found in Canada for the first time.

Canada


A dengue outbreak has killed at least 21 people in India’s southern state of Kerala in the past three weeks.

Reuters

 


A new antibody-based assay distinguishes Zika from similar viral infections

Eureka

“A new test is the best-to-date in differentiating Zika virus infections from infections caused by similar viruses. The antibody-based assay, developed by researchers at UC Berkeley and Humabs BioMed, a private biotechnology company, is a simple, cost-effective way to determine if a person’s infection is from the Zika virus or another virus of the same family, such as dengue and West Nile viruses….”

PNAS

“…..This study demonstrates that the antibody-based assay we developed and implemented in five countries has high specificity and sensitivity in the detection of recent and past ZIKV infections. The ZIKV nonstructural protein 1 (NS1) blockade-of-binding ELISA assay is a simple, robust, and low-cost solution for Zika surveillance programs, seroprevalence studies, and intervention trials in flavivirus-endemic areas….”


WHO: New vector control response seen as game-changer

WHO

The call came from the WHO Director-General in May 2016 for a renewed attack on the global spread of vector-borne diseases.

“What we are seeing now looks more and more like a dramatic resurgence of the threat from emerging and re-emerging infectious diseases,” Dr Margaret Chan told Member States at the Sixty-ninth World Health Assembly. “The world is not prepared to cope.”

Dr Chan noted that the spread of Zika virus disease, the resurgence of dengue, and the emerging threat from chikungunya were the result of weak mosquito control policies from the 1970s. It was during that decade that funding and efforts for vector control were greatly reduced.

‘Vector control has not been a priority’

Dr Ana Carolina Silva Santelli has witnessed this first-hand. As former head of the programme for malaria, dengue, Zika and chikungunya with Brazil’s Ministry of Health, she saw vector-control efforts wane over her 13 years there. Equipment such as spraying machines, supplies such as insecticides and personnel such as entomologists were not replaced as needed. “Vector control has not been a priority,” she said.

Today more than 80% of the world’s population is at risk of vector-borne disease, with half at risk of two or more diseases. Mosquitoes can transmit, among other diseases, malaria, lymphatic filariasis, Japanese encephalitis and West Nile; flies can transmit onchocerciasis, leishmaniasis and human African trypanosomiasis (sleeping sickness); and bugs or ticks can transmit Chagas disease, Lyme disease and encephalitis.

Together, the major vector-borne diseases kill more than 700 000 people each year, with populations in poverty-stricken tropical and subtropical areas at highest risk. Other vector-borne diseases, such as tick-borne encephalitis, are of increasing concern in temperate regions.

Rapid unplanned urbanization, massive increases in international travel and trade, altered agricultural practices and other environmental changes are fuelling the spread of vectors worldwide, putting more and more people at risk. Malnourished people and those with weakened immunity are especially susceptible.

A new approach

Over the past year, WHO has spearheaded a new strategic approach to reprioritize vector control. The Global Malaria Programme and the Department of Control of Neglected Tropical Diseases – along with the Special Programme for Research and Training in Tropical Diseases, have led a broad consultation tapping into the experience of ministries of health and technical experts. The process was steered by a group of eminent scientists and public health experts led by Dr Santelli and Professor Thomas Scott from the Department of Entomology and Nematology at the University of California, Davis and resulted in the Global Vector Control Response (GVCR) 2017–2030.

At its Seventieth session, the World Health Assembly unanimously welcomed the proposed response.

The GVCR outlines key areas of activity that will radically change the control of vector-borne diseases:

  • Aligning action across sectors, since vector control is more than just spraying insecticides or delivering nets. That might mean ministries of health working with city planners to eradicate breeding sites used by mosquitoes;
  • Engaging and mobilizing communities to protect themselves and build resilience against future disease outbreaks;
  • Enhancing surveillance to trigger early responses to increases in disease or vector populations, and to identify when and why interventions are not working as expected; and
  • Scaling-up vector-control tools and using them in combination to maximize impact on disease while minimizing impact on the environment.

Specifically, the new integrated approach calls for national programmes to be realigned so that public health workers can focus on the complete spectrum of relevant vectors and thereby control all of the diseases they cause.

Recognizing that efforts must be adapted to local needs and sustained, the success of the response will depend on the ability of countries to strengthen their vector-control programmes with financial resources and staff.

A call to pursue novel interventions aggressively

The GVCR also calls for the aggressive pursuit of promising novel interventions such as devising new insecticides; creating spatial repellents and odour-baited traps; improving house screening; pursuing development of a common bacterium that stops viruses from replicating inside mosquitoes; and modifying the genes of male mosquitoes so that their offspring die early.

Economic development also brings solutions. “If people lived in houses that had solid floors and windows with screens or air conditioning, they wouldn’t need a bednet,” said Professor Scott. “So, by improving people’s standard of living, we would significantly reduce these diseases.”

An entomologist inserts live mosquitoes in wall of a mud house in Kisumu, Kenya

An entomologist inserts live mosquitoes into a standard ‘cone bioassay’. After 30 minutes he will see how many have been killed – this will measure if the insecticide was sprayed properly on the walls, and constitutes intervention monitoring.
WHO/S. Torfinn

The call for a more coherent and holistic approach to vector control does not diminish the considerable advances made against individual vector-borne diseases.

Malaria is a prime example. Over the past 15 years, its incidence in sub-Saharan Africa has been cut by 45% – primarily due to the massive use of insecticide-treated bed nets and spraying of residual insecticides inside houses.

But that success has had a down side.

“We’ve been so successful, in some ways, with our control that we reduced the number of public health entomologists – the people who can do this stuff well,” said Professor Steve Lindsay, a public health entomologist at Durham University in Britain. “We’re a disappearing breed.”

The GVCR calls for countries to invest in a vector-control workforce trained in public health entomology and empowered in health care responses.

“We now need more nuanced control – not one-size-fits-all, but to tailor control to local conditions,” Professor Lindsay said. This is needed to tackle new and emerging diseases, but also to push towards elimination of others such as malaria, he said.

Dr Lindsay noted that, under the new strategic approach, individual diseases such as Zika, dengue and chikungunya will no longer be considered as separate threats. “What this represents is not three different diseases, but one mosquito – Aedes aegypti,” said Professor Lindsay.

GVCR dovetails with Sustainable Development Goals

The GVCR will also help countries achieve at least 6 of the 17 Sustainable Development Goals. Of direct relevance are goal 3 on good health and well-being, goal 6 on clean water and sanitation, and goal 11 on sustainable cities and communities.

The GVCR goals are ambitious – to reduce mortality from vector-borne diseases by at least 75% and incidence by at least 60% by 2030 – and to prevent epidemics in all countries.

The annual price tag is US$ 330 million globally, or about 5 cents per person – for workforce, coordination and surveillance costs. This is a modest additional investment in relation to insecticide-treated nets, indoor sprays and community-based activities, which usually exceed US$ 1 per person protected per year.

It also represents less than 10% of what is currently spent each year on strategies to control vectors that spread malaria, dengue and Chagas disease alone. Ultimately, the shift in focus to integrated and locally adapted vector control will save money.

‘A call for action’

Dr Santelli expressed optimism that the GVCR will help ministries of health around the world gain support from their governments for a renewed focus on vector control.

“Most of all, this document is a call for action,” said Dr Santelli, who now serves as deputy director for epidemiology in the Brasilia office of the U.S. Centers for Disease Control and Prevention.

It will not be easy, she predicts. The work to integrate vector-control efforts across different diseases will require more equipment, more people and more money as well as a change in mentality. “The risk of inaction is greater,” said Dr Santelli, “given the growing number of emerging disease threats.” The potential impact of the GVCR is immense: to put in place new strategies that will reduce overall burden and, in some places, even eliminate these diseases once and for all.


edes aegypti mosquitoes that carry Zika can also transmit dengue and chikungunya in the same bite.

Nature

Rückert, C. et al. Impact of simultaneous exposure to arboviruses on infection and transmission by Aedes aegypti mosquitoes. Nat. Commun. 8, 15412 doi: 10.1038/ncomms15412 (2017).

“…..Thus, we here expose Ae. aegypti mosquitoes to chikungunya, dengue-2 or Zika viruses, both individually and as double and triple infections. Our results show that these mosquitoes can be infected with and can transmit all combinations of these viruses simultaneously. Importantly, infection, dissemination and transmission rates in mosquitoes are only mildly affected by coinfection…..”


Categories

Recent Posts

Archives

Admin