WHO Update: Guillain-Barré Syndrome (GBS) In Brazil and Martinique

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Yesterday, in Guillain-Barre syndrome: The Other Zika Concern, we looked at the suspected - but as yet unproven - link between the recent arrival of Zika to the Americas and French Polynesia and reports of a concurrent rise in cases of Guillain-Barré Syndrome.  

Along the way we also looked at previous outbreaks and individual cases of GBS that have been attributed to a variety of causes, including some linked to arboviral infections like Dengue and Chikungunya.

In early 2014 in Zika, Dengue & Unusual Rates Of Guillain Barre Syndrome In French Polynesia we got our first clue that something unexpected was going on with Zika, and over the past couple of months we've seen reports of increased GBS in Brazil, Colombia, El Salvador, Suriname, and Venezuela - all countries where Zika has recently arrived.


Complicating matters, Zika isn't the only arbovirus circulating in these countries. Dengue has been around for decades, but Chikungunya only began to spread widely in the Americas in early 2014.

Many of those who are now falling victim to Zika have previously had CHKV and/or  Dengue (I-4), raising questions over the potential impact of concurrent or sequential infection.

And trying to compare the rates of GBS from previous years - when surveillance and reporting may not have been particularly thorough - to today, when doctors are actively looking for cases, can produce misleading numbers.

Still - just as with microcephaly in Brazil - something seems to be driving the rates of GBS substantially higher these seven countries.  And right now Zika - or perhaps Zika combined another factor - is at the top of the suspect list.

The World Health Organization published two GBS updates overnight, with the first - from Martinique - of particular interest because it describes two recent Guillain-Barré cases, both of whom have tested positive for the Zika virus. 


The update from Brazil describes major increases in GBS in some states, but stable rates (or even declines) in others, leaving us with an incomplete, and muddled picture.  As with the apparent increases in microcephalic births, there are still more questions than answers.

Guillain-Barré syndrome – France - Martinique

Disease Outbreak News
8 February 2016

On 25 January 2016, the National IHR Focal Point of France notified PAHO/WHO of 2 cases of Guillain-Barré Syndrome (GBS) in Martinique.

Details of the cases

• The first case is a 19-year-old with onset of symptoms (paraesthesia of hands and feet) on 26 December. Urine samples, which were taken on 7 January, tested positive for Zika virus by reverse transcription polymerase chain reaction (RT-PCR) at the University Hospital of Martinique. Currently, the patient is being intubated and ventilated in an intensive care unit.
• The second case is a 55-year-old who was admitted to an intensive care unit on 21 January. On the same day, urine samples were collected from the patient. The samples tested positive for Zika virus by RT-PCR at the University Hospital of Martinique. Currently, the patient is being ventilated because of his respiratory failure.

WHO risk assessment

At present, available information is insufficient to interpret the observed differences in GBS incidence globally and among Brazilian states. The potential cause of the reported increase of GBS incidence in certain Brazilian states remains unknown. Case-control studies are ongoing to determine the cause of the increase. These studies may provide evidence that corroborates or disproves a causal relationship between Zika virus, GBS and other congenital malformations. WHO continues to monitor the epidemiological situation and conduct risk assessment based on the latest available information.

WHO recommends Member States affected or susceptible to Zika virus outbreaks to:

• monitor the incidence and trends of neurological disorders, especially GBS, to identify variations against their expected baseline values;
• develop and implement sufficient patient management protocols to manage the additional burden on health care facilities generated by a sudden increase in patients with Guillain-Barre Syndrome;
• raise awareness among health care workers and establish and/or strengthen links between public health services and clinicians in the public and private sectors.

WHO advice

The proximity of mosquito vector breeding sites to human habitation is a significant risk factor for Zika virus infection. Prevention and control relies on reducing the breeding of mosquitoes through source reduction (removal and modification of breeding sites) and reducing contact between mosquitoes and people. This can be achieved by reducing the number of natural and artificial water-filled habitats that support mosquito larvae, reducing the adult mosquito populations around at-risk communities and by using barriers such as insect screens, closed doors and windows, long clothing and repellents. Since the Aedes mosquitoes (the primary vector for transmission) are day-biting mosquitoes, it is recommended that those who sleep during the daytime, particularly young children, the sick or elderly, should rest under mosquito nets (bed nets), treated with or without insecticide to provide protection. 

During outbreaks, space spraying of insecticides may be carried out following the technical orientation provided by WHO to kill flying mosquitoes. Suitable insecticides (recommended by the WHO Pesticide Evaluation Scheme) may also be used as larvicides to treat relatively large water containers, when this is technically indicated.

Basic precautions for protection from mosquito bites should be taken by people traveling to high risk areas, especially pregnant women. These include use of repellents, wearing light colored, long sleeved shirts and pants and ensuring rooms are fitted with screens to prevent mosquitoes from entering. 

WHO does not recommend any travel or trade restriction to France and the overseas departments of France based on the current information available.

Guillain-Barré syndrome – Brazil

Disease Outbreak News
8 February 2016 

On 22 January 2016, the National IHR Focal Point of Brazil notified PAHO/WHO of an increase of Guillain-Barre Syndrome (GBS) recorded at the national level. 

Data from the hospital-based surveillance system reveal that, between January and November 2015, 1,708 cases of GBS were registered nationwide. While a number of states reported significant increases in reported cases – especially, Alagoas (516.7%), Bahia (196.1%), Rio Grande do Norte (108.7%), Piauí (108.3%), Espirito Santo (78.6%), and Rio de Janeiro (60.9%) – other states reported stable or even diminishing number of GBS cases as compared to 2014. Most of the states in Brazil are experiencing the circulation of Zika, chikungunya, and dengue virus.

WHO risk assessment

At present, available information is insufficient to interpret the observed differences in GBS incidence globally and among Brazilian states. The potential cause of the reported increase of GBS incidence in certain Brazilian states remains unknown. Case-control studies are ongoing to determine the cause of the increase. These studies may provide evidence that corroborates or disproves a causal relationship between Zika virus, GBS and other congenital malformations. WHO continues to monitor the epidemiological situation and conduct risk assessment based on the latest available information.

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RESEP TUMIS KANGKUNG CAH DAGING SAPI

Resep Tumis Kangkung - Sederhana memang, namun masakan cah kangkung atau tumisan kangkung dengan karakter cita rasanya yang khas dapat memberikan kesan spesial dalam melengkapi menu sayuran hijau segar sehari-hari.

Aneka tumisan kangkung juga biasa disediakan dalam pilihan menu resto dan kafe, walaupun dalam menu makan sehari-hari di rumah kita sering mengolahnya sendiri. Variasi cara membuatnya juga sangat beragam, seperti halnya pada resep tumis kangkung daging sapi kali ini.

Persiapan Bahan Bumbu Tumis Kangkung

• 2 ikat kangkung, siangi dan cuci bersih
• 100 gram daging sapi diiris tipis
• 3 butir bawang merah diiris tipis
• 2 siung bawang putih diiris tipis
• 3 cm jahe diiris tipis
• 2 sdm kecap manis
• 1 sdm saus tiram
• 1 sdt minyak wijen
• 1 sdt lada/merica bubuk
• 1/2 sdt garam
• 1/2 sdt gula pasir
• 1/4 sdt kaldu bubuk
• 150 ml air
• 1 sdm tepung maizena dilarutkan sedikit air
• minyak secukupnya untuk menumis

Cara Membuat Tumis Kangkung Cah Daging Sapi

1. Panaskan sedikit minyak dalam wajan, lalu tumis bawang merah , bawang putih dan jahe hingga harum. Masukkan irisan daging sapi serta masak hingga berubah warna, kemudian tuang air, kecap manis, saus tiram, minyak wijen, lada, garam, gula, dan kaldu bubuk.
2. Aduk rata dan masak hingga mendidih, masukkan larutan maizena serta aduk hingga kuah mengental. Terakhir masukkan daun kangkung, masak sebentar lalu angkat dan siap untuk disajikan.

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CDC Statement On Level 1 Activation Of Their EOC For Zika

Credit WHO/PAHO week 5 Zika Spread

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The CDC posted a link this afternoon to the following statement - which is dated Feb 3rd on their website - announcing their Emergency Operations Center (EOC) is moving to a Level 1 activation status for Zika.

CDC Emergency Operations Center moves to highest level of activation for Zika response

Media Statement

For Immediate Release: Wednesday, February 3, 2016Contact: Media Relations, (404) 639-3286

To further enhance its response to the Zika virus outbreak, CDC’s Emergency Operations Center is moving to a Level 1 activation—reflecting the agency’s assessment of the need for an accelerated preparedness to bring together experts to focus intently and work efficiently in anticipation of local Zika virus transmission by mosquitoes in the Continental U.S.
  
Activated for the Zika response since January 22, 2016,  the EOC is the command center for monitoring and coordinating the emergency response to Zika, bringing together CDC scientists with expertise in arboviruses, reproductive health, and birth and developmental defects. Their work includes:

• Developing laboratory tests to diagnose Zika
• Conducting studies to learn more about the possible linkages with microcephaly and Guillain Barré syndrome
• Surveillance for the virus in the United States, including US territories
• On-the-ground support in Puerto Rico, Brazil and Colombia

The EOC is currently home to more than 300 CDC staff working in collaboration with local, national, and international response partners to analyze, validate, and efficiently exchange information about the outbreak. The EOC has resources to rapidly transport diagnostic kits, samples and specimens, and personnel. The EOC is serving as CDC's command center for monitoring and coordinating the emergency response to Zika, including the deployment of CDC staff and the procurement and management of all equipment and supplies that CDC responders may need during deployment.

B-roll of Zika response in CDC Emergency Operations Center: http://www.cdc.gov/media/b_roll.html.

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CDC: New Lyme-Disease-Causing Bacteria Species Discovered

Credit CDC

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Having contracted Lyme Disease back in the mid-1990s, I have a particular interest in tick borne diseases (and a deep seated hatred for ticks), and have written about them fairly frequently over the years.


Some of my blogs on recently discovered viruses carried by ticks include:

CDC & EID Journal On The Recently Discovered Bourbon Virus

EID Journal: Novel Bunyavirus In Livestock – Minnesota

MMWR: Heartland Virus Disease — United States, 2012–2013

Far more common is Lyme disease, which the CDC estimates may affect 300,000 Americans every year.  The CDC maintains a long  (and growing) list of of tick borne pathogens available in North America, including:

Anaplasmosis, Babesiosis, Borrelia miyamotoi, Colorado tick fever, Ehrlichiosis, Heartland virus, Lyme disease, Powassan disease, Rickettsia parkeri rickettsiosis ,Rocky Mountain spotted fever (RMSF), STARI (Southern tick-associated rash illness)Tickborne relapsing fever (TBRF), Tularemia,364D rickettsiosis 

To this growing rogues gallery we can now add Borrelia mayonii, which has recently been discovered to be causing a Lyme-like illness in Minnesota and Wisconsin. Details of this discovery are contained in the following CDC statement.

New Lyme-disease-causing bacteria species discovered

Borrelia mayonii closely related to B. burgdorferi

Press Release

For Immediate Release: Monday, February 8, 2016Contact: Media Relations (404) 639-3286

The Centers for Disease Control and Prevention, in collaboration with Mayo Clinic and health officials from Minnesota, Wisconsin, and North Dakota, report the discovery of a new species of bacteria (Borrelia mayonii) that causes Lyme disease in people. Until now, Borrelia burgdorferi was the only species believed to cause Lyme disease in North America.

Scientists at the Mayo Clinic in Rochester, Minnesota, first suspected the possibility of new bacteria after lab tests from six people with suspected Lyme disease produced unusual results, according to the findings published today in Lancet Infectious Diseases. Additional genetic testing at the Mayo Clinic and CDC found that the bacteria, provisionally named Borrelia mayonii, is closely related to B. burgdorferi.

“This discovery adds another important piece of information to the complex picture of tickborne diseases in the United States,” said Dr. Jeannine Petersen, microbiologist at the Centers for Disease Control and Prevention.

So far, new Lyme species found only in upper Midwest

Limited information from the first six patients suggests that illness caused by B. mayonii is similar to that caused by B. burgdorferi, but with a few possible differences. Like B. burgdorferi, B. mayonii causes fever, headache, rash, and neck pain in the early stages of infection (days after exposure) and arthritis in later stages of infection (weeks after exposure). Unlike B. burgdorferi, however, B. mayonii is associated with nausea and vomiting, diffuse rashes (rather than a single so-called “bull’s-eye” rash), and a higher concentration of bacteria in the blood.

The researchers believe that, like B. burgdorferi, B. mayonii is transmitted to humans by the bite of an infected blacklegged (or “deer”) tick. B. mayonii has been identified in blacklegged ticks collected in at least two counties in northwestern Wisconsin. The likely exposure sites for the patients described in Lancet Infectious Diseases are in north central Minnesota and western Wisconsin. It is highly likely, however, that infected ticks are found throughout both states.

The newly recognized species was discovered when six of approximately 9,000 samples drawn from residents of Minnesota, Wisconsin, and North Dakota with suspected Lyme disease between 2012 and 2014 were found to contain bacteria that were genetically distinct from B. burgdorferi. Scientists analyzed the DNA sequences of these bacteria and found that they belonged to a previously unrecognized Borrelia species. Blood from two of the patients was also tested by culture at CDC, whereby the organism is grown in the laboratory.

To date, the evidence suggests that the distribution of B. mayonii is limited to the upper midwestern United States. The new species was not identified in any of the approximately 25,000 blood samples from residents of 43 other states with suspected tickborne disease taken during the same period, including states in the Northeast and Mid-Atlantic region where Lyme disease is common.

Current tests, treatments should work for new Lyme strain

Results from the cases described in this report suggest that patients infected with B. mayonii will test positive for Lyme disease with currently available Food and Drug Administration-cleared Lyme disease tests. Specific identification of the organism can be made by using polymerase chain reaction assays (PCR.), which detects the DNA of the Lyme disease bacteria. In some instances, B. mayonii bacteria may also be seen on a blood smear.

The patients described in this report were treated successfully with antibiotics commonly used to treat Lyme disease caused by B. burgdorferi. CDC recommends that health care providers who treat people infected with B. mayonii follow the antibiotic regimen described by the Infectious Diseases Society of America.

CDC is working closely with state health departments in Minnesota, North Dakota, and Wisconsin to better understand B. mayonii and to plan future investigations, including better descriptions about the clinical aspects of the illness and the geographic extent of the infected ticks.

To further support advances in the detection and discovery of tickborne diseases, CDC in 2015 funded a partnership with the Minnesota Department of Health, Mayo Clinic, Tennessee Department of Health, and Vanderbilt University to collect over a 3-year period up to 30,000 clinical specimens from patients with suspected tickborne illness. CDC will use advanced molecular detection methods, including metagenomics screening and whole genome sequencing, to test the specimens for other bacteria that cause tickborne illness.

"CDC is investing in advanced technology to bring study of tickborne infections into a new era," said Ben Beard, Ph.D., chief of CDC’s Bacterial Diseases Branch. "Coupling technology with teamwork between federal, state, and private entities will help improve early and accurate diagnosis of tickborne diseases.”

To reduce the risk of tick bites and tickborne diseases, CDC recommends that people:

• Avoid wooded and brushy areas with high grass and leaf litter;
• Use insect repellent when outdoors;
• Use products that contain permethrin on clothing;
• Bathe or shower as soon as possible after coming indoors to wash off and more easily find ticks;
• Conduct a full-body tick check after spending time outdoors; and
• Examine gear and pets, as ticks can come into the home on these and later attach to people.

To view the article online: http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(15)00483-1/fulltext

For more information, please visit www.cdc.gov/ticks.

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ECDC Risk Assessment : Reports Of Severe A(H1N1)pdm09 In Europe

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Although influenza has been late in arriving this year in North America (and Western Europe) for the past couple of weeks we've been watching reports of unusually severe influenza in Russia and Eastern Europe, with Russian epidemiological reports indicating a new subgroup of A(H1N1) has recently emerged.

Updating Russia's Flu Outbreak

An Update On The Russian Influenza Epi Report

A Russian Influenza Epidemiology Report To Ponder

The most recent (week 5) Russian Epidemiology report states:

Genetic characterization. 55 investigated influenza A(H1N1)pdm09 virus strains were A/South Africa/3626/2013-like. All viruses bear clade 6B specific mutations in HA (S84N, S162+N and I216T) and formed new genetic group according to phylogenetic analysis. Two A(H1N1)pdm09 sequences obtained directly from autopsy sample showed the presence of additional mutation D222G in HA1.

We've discussed the significance of the D222G mutation a number of times (see here & here), but essentially it promotes lower lung infections, and is linked to increased virulence. The Russian epi report also mentions reduced titers against the current vaccine strain for some viruses sampled.

Despite the lack of North American flu cases so far, last Monday the CDC issued a HAN Advisory: Severe Influenza Illness Reported. 

Today, the ECDC cites - strong indications from some EU/EEA countries that the A(H1N1)pdm09 virus is responsible for the hospitalisation of a large number of severe cases - and published the following mid-season risk assessment.

A(H1N1)pdm09 dominant influenza strain in Europe: mid-season risk  assessment



08 Feb 2016

This year’s seasonal influenza risk assessment identifies type A viruses, in particular A(H1N1)pdm09, as dominant thus far in EU/EEA countries. There are strong indications from some EU/EEA countries that the A(H1N1)pdm09 virus is responsible for the hospitalisation of a large number of severe cases. This includes hospitalisations for severe outcomes for both risk groups and otherwise healthy young adults. A similar pattern of severity is likely to be observed in other countries as the season progresses.

The season started in EU/EEA countries in week 52/2015, with the Netherlands reporting regional spread, while Sweden reported widespread activity. The A(H1N1)pdm09 virus is the most prevalent so far this season overall but B viruses predominated in four countries, and three countries had an even distribution of both A and B viruses. B viruses could emerge later and become dominant by the end of the season. In previous seasons, B viruses have tended to be more prevalent in the second half of the season.

The A(H1N1)pdm09 virus is responsible for the vast majority of patients in intensive care units due to influenza; 61% of those were in the 15–64 years old age group. This contrasts with the 2014–15 season where the predominant A(H3N2) virus affected the elderly more.

Seasonal influenza vaccine effectiveness

The composition of influenza vaccines in the southern hemisphere in 2015 and in the northern hemisphere in 2015–16 were identical and thus provide an indication of how effective vaccination could be in Europe. Estimates of vaccine effectiveness in New Zealand are encouraging, with an overall effectiveness against hospitalisations of 50%.

For Europe, the vaccine effectiveness is expected to be lower than in the 2015 season in New Zealand. Europe is seeing a higher prevalence of B/Victoria virus circulating, which is not included in the widely used trivalent vaccine, and it is unclear if the emergence of a new genetic subgroup of A(H1N1) virus might compromise vaccine effectiveness.

Susceptibility to antiviral drugs

Almost all viruses tested for neuraminidase inhibitor (antiviral) susceptibility, showed no reduction in effectiveness.

ECDC advises:

Simple measures such as self-isolation, good hand hygiene and cough etiquette can reduce transmission and protect others.

Early treatment and post-exposure prophylaxis with neuraminidase inhibitors (antivirals) can assist in protecting the elderly and people in risk groups against serious influenza illness.

EU Member States are encouraged to report ICU-admitted, laboratory-confirmed influenza cases to the European Surveillance System (TESSy) in a timely fashion in order to facilitate the assessment of the severity of the season.

 
Although influenza season normally peaks by February, every flu season is different, and we may still be on pace to see a late onset flu season.  It isn't too late to get a flu shot, and as always, it is important to practice good flu hygiene.

As for the ultimate impact and significance of the changes being reported in the H1N1 virus, we'll just have to wait and see.  

Last week we looked at similar changes reported in India in 2015, in Eurosurveillance: Emergence of A(H1N1)pdm09 Genogroup 6B In India, 2015. There you will also find further discussion of the H275Y mutation which confers resistance to Oseltamivir.

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WHO Update - Zika Virus Infection In the Americas

Credit WHO/PAHO



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The World Health Organization has published the following update and risk assessment on the spread of the Zika Virus in the Americas.

Zika virus infection – Region of the Americas

Disease Outbreak News
8 February 2016 

Between 27 and 30 January 2016, PAHO/WHO was notified of cases of Zika virus infection in Costa Rica, Curaçao, Jamaica and Nicaragua.

Costa Rica

On 27 January, the National IHR Focal Point of the United States reported of a case of Zika virus infection in a patient returning from Costa Rica.

The patient from Northeastern United States was evaluated on 7 January for a febrile illness with rash, conjunctivitis and arthralgia. From 19 to 26 December, the patient stayed with 2 family members in Nosara, Costa Rica. While in the country, the patient reported several mosquito bites.

The patient developed symptoms on 30 December and presented to clinical care between 2 and 3 January. Tests performed at that time were negative for malaria (smears), and dengue and chikungunya IgM and IgG antibodies. The patient was seen again on 7 January. Dengue and chikungunya serologic testing performed through a commercial laboratory was positive for dengue IgM, negative for dengue IgG, and negative for chikungunya IgM and IgG. Samples of the patient were sent to the U.S. Centers for Disease Control and Prevention where they tested positive for Zika virus and dengue IgM. Plaque reduction neutralization testing yielded positive titers for Zika virus at >5120 and negative titers for dengue virus titers <10 .="" br="">

The patient has fully recovered while the 2 family members that also travelled to Costa Rica have remained well.

Curaçao

On 28 January, the National IHR Focal Point of the Netherlands reported the first autochthonous case of Zika virus infection in Curaçao. Curaçao is an independent state and part of the Kingdom of the Netherlands and is situated in the southern part of the Caribbean region just north of the Venezuelan coast.

The case is a woman of 41-year-old woman with onset of symptoms (conjunctivitis, arthralgia, myalgia, rash and diarrhoea) on 17 January. A serum sample was collected on 21 January and tested at the Analytic Diagnostic Centre in Willemstad, Curaçao, where the diagnosis was confirmed by polymerase-chain reaction (PCR) on 25 January.

In the continental part of the Netherlands, to date, 13 imported cases of Zika virus infection have been confirmed. All diagnoses were made by PCR. All these patients have a history of recent travel to Suriname.

One additional imported case was confirmed in Curaçao earlier on in the year. This patient, too, has a history of recent travel to Suriname.

Jamaica

On 30 January, the National IHR Focal Point of Jamaica reported a case of Zika virus infection.

The patient is a 4-year-old female with onset of fever on 17 January. On 19 January, she developed a generalized rash, abdominal pain, retro-orbital pain, headache, vomiting and red eyes. On 20 January, the patient developed joint pains. Symptoms subsided by 24 January.

The patient travelled to Dallas, United States of America on 20 December and returned to Jamaica on 4 January via Miami, USA.

A serum sample was collected from the patient on 21 January and sent to the Caribbean Public Health Agency (CARPHA) for laboratory testing. The diagnosis of Zika virus infection was confirmed by PCR.

Nicaragua

On 27 January, the National IHR Focal Point of Nicaragua reported the country’s first 2 laboratory-confirmed cases of locally-acquired Zika virus infection.
The cases are females from the Managua department. They presented fever, rash and conjunctivitis. Currently, both patients are in stable condition. The cases were confirmed by PCR at the Centro Nacional de Diagnóstico y Referencia of the Nicaraguan Ministry of Health.

WHO risk assessment

The detection of autochthonous cases of Zika virus infection indicates that the virus is spreading geographically to previously unaffected areas (Costa Rica, Curaçao, Jamaica and Nicaragua). The notification of autochthonous transmission in a new country does not change the overall risk assessment. The risk of a global spread of Zika virus to areas where the competent vectors, the Aedes mosquitoes, are present is significant given the wide geographical distribution of these mosquitoes in various regions of the world. WHO continues to monitor the epidemiological situation and conduct risk assessment based on the latest available information.

Despite reports of a potential association between Zika virus, microcephaly and other neurological disorders, a causal relationship between these events has not yet been confirmed. Until more is understood, Members States are advised to standardize and enhance surveillance for microcephaly and other neurological disorders, particularly in areas of known Zika virus transmission and areas at risk of such transmission.

WHO advice

The proximity of mosquito vector breeding sites to human habitation is a significant risk factor for Zika virus infection. Prevention and control relies on reducing the breeding of mosquitoes through source reduction (removal and modification of breeding sites) and reducing contact between mosquitoes and people. This can be achieved by reducing the number of natural and artificial water-filled habitats that support mosquito larvae, reducing the adult mosquito populations around at-risk communities and by using barriers such as insect screens, closed doors and windows, long clothing and repellents. Since the Aedes mosquitoes (the primary vector for transmission) are day-biting mosquitoes, it is recommended that those who sleep during the daytime, particularly young children, the sick or elderly, should rest under mosquito nets (bed nets), treated with or without insecticide to provide protection.

During outbreaks, space spraying of insecticides may be carried out following the technical orientation provided by WHO to kill flying mosquitoes. Suitable insecticides (recommended by the WHO Pesticide Evaluation Scheme) may also be used as larvicides to treat relatively large water containers, when this is technically indicated.

Basic precautions for protection from mosquito bites should be taken by people traveling to high risk areas, especially pregnant women. These include use of repellents, wearing light colored, long sleeved shirts and pants and ensuring rooms are fitted with screens to prevent mosquitoes from entering.

WHO does not recommend any travel or trade restriction to Costa Rica, Curaçao, Jamaica and Nicaragua based on the current information available.

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Guillain-Barre syndrome: The Other Zika Concern

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Although the primary concern right now with the Zika virus is its tentative link to microcephalic birth defects, a secondary concern has been the concurrent rise in the number of Guillain-Barre syndrome cases in French Polynesia and South and Central America following Zika's arrival.

Today, a brief overview of this rare neurological condition.

Not quite 40 years ago Guillain-Barre syndrome (GBS) made global headlines following the roll-out of the 1976 emergency swine flu vaccine, which after 40 million doses were administered, was linked to roughly 500 cases of (mostly temporary) paralysis and 25 deaths.

I was a young paramedic at the time, and chronicled my little part in that bit of influenza history several years ago in Deja Flu, All Over Again. 

In the nearly 4 decades since that fiasco, there has been little or no evidence of flu shots causing Guillain-Barre Syndrome - and since influenza infection has been linked to causing GBS - the flu shot is believed to have reduced the number of GBS cases over the years (see  Lancet: The Influenza - Guillain Barré Syndrome Connection).

While the exact cause of GBS isn't well understood, we do know that most cases occur after a bacterial or viral infection. Camplyobacter Jejuni, in particularly, has been linked to GBS, but other bacterial and viral infections (including influenza and Dengue) have as well.

GBS isn't a single neurological illness, but rather a collection of syndromes all of which damage nerve cells, resulting in muscle weakness and sometimes paralysis. With modern medical treatment (including Intravenous immunoglobulin (IVIG), plasma exchange, and ventilatory assistance if needed), most victims survive.

But between 5%-10% of GBS cases are fatal, and a large percentage of survivors carry forward some form of neurological sequelae (cite), including motor deficits, persistent fatigue, and sensory loss.

There are a number of GBS variants (whose symptoms often overlap) with their incidence varying around the world.  A few of the major subtypes include:
 

• Acute inflammatory demyelinating polyneuropathy (or AIDP) is the most common form of GBS reported in the United States.
• Acute motor axonal neuropathy (AMAN) is more prevalent in pediatric age groups, with many cases reported in rural China. Once again, C jejuni infection is often linked to onset.
• Acute motor-sensory axonal neuropathy (AMSAN) typically affects adults. 
• Miller-Fisher syndrome is observed in about 5% of all cases of GBS, and presents as a triad of ataxia, areflexia, and ophthalmoplegia. Recovery generally occurs within 1-3 months.
• Acute panautonomic neuropathy is the rarest GBS variant, Cardiovascular involvement is common and recovery is often slow and incomplete.

 
Now that polio is no longer a factor, GBS (in all of its forms) is the primary cause of acute flaccid paralysis (AFP) in the the United States with an incidence of between 1.2 and 3.0 per 100,000 (3,000 to 9,000 cases annually).

In 2011 we looked at a rare cluster of GBS linked to C jejuni water contamination in  The Sonora/Arizona GBS Cluster, but most cases are one-offs, and are not epidemiologically linked.

Almost two years ago, in Zika, Dengue & Unusual Rates Of Guillain Barre Syndrome In French Polynesia, we saw an outbreak of Zika in the South Pacific that – quite unusually – seemed to be linked to an increase in Guillain Barré Syndrome cases. In March 2014 the journal Eurosurveillance carried a Rapid Communications describing the first case and reporting a 20-fold increase in GBS during the outbreak.


Since then we've seen apparent spikes in GBS in Brazil, El Salvador, and other regions where Zika has recently emerged.  While a causal link has not been established, the WHO cited the rise in GBS as one of the factors in declaring Zika a public health emergency a week ago, and on Friday CDC director Thomas Frieden indicated that the linkage between Zika and GBS grows stronger the more we learn.

Infection by other mosquito-borne viruses - such as Dengue, Chikunungya, EEE, and West Nile Virus  - are known to occasionally cause serious neurological symptoms, including AFP (acute flaccid paralysis), making a Zika-GBS link at least plausible. 

While the literature isn't exactly overflowing, some relevant links include:

Guillain-Barre syndrome following dengue fever and literature review.

Guillain-Barre syndrome occurring during dengue fever.

Guillain-Barré Syndrome after Chikungunya Infection

Neuromuscular Manifestations of West Nile Virus Infection

Dengue infection: An emerging cause of neuromuscular weakness

The good news in all of this is that neuroinvasive illness from arboviral infections (Dengue, CHKV, WNV, and Zika) are very rare, and many infections can be avoided by taking some simple mosquito precautions.

The 5 D's of Mosquito Protection

It should be noted that the Aedes mosquitoes, linked to Zika and Dengue transmission, are aggressive daytime biters - and so it is important to protect yourself throughout the day.

And lastly, a  2003 CDC EID study found that economics and lifestyle (window screens, A/C, etc.) may help to limit the spread of arboviruses in the United States (see Texas Lifestyle Limits Transmission of Dengue Virus) - at least compared to many tropical regions.


None of this is to suggest there won't be some places in the U.S. that could see limited outbreaks of Zika, only that the kind of pervasive spread we've seen in Central and South America seems unlikely in the United States at this time.

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