Tuesday, May 22, 2018

A Pre-Season Reminder To Prepare


The GFS and Euro Models have been hinting at something developing in the Western Caribbean for the past week or so, and yesterday the National Hurricane Center added it to their 5 day tropical weather outlook.
This morning, they put the chances of development at 40% over the next 5 days, and while it will probably top out as a rain-making  depression or weak tropical storm, it is a reminder that the start to the Atlantic Hurricane Season is just over a week away.
 This morning's 8am update reads:

745 AM EDT Tue May 22 2018

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. A broad surface low centered just east of Belize is producing a large area of cloudiness and showers extending from the northwestern Caribbean Sea across Cuba into the Florida peninsula.  While strong upper-level winds and dry air aloft are expected to limit organization during the next couple of days, some gradual subtropical or tropical development is possible late this week while the system moves slowly northward into the central or eastern Gulf of Mexico.
Regardless of development, locally heavy rainfall is possible across western Cuba, the Cayman Islands, and much of Florida during the next several days.  For more information on the heavy rain threat, please see products issued by your local weather office. The next Special Tropical Weather Outlook on this system will be issued by 800 PM EDT.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...40 percent.

Forecaster Blake

As we discussed two weeks ago in Hurricane Preparedness Week 2018 (May 6th - May 12th), NOW is the time to make your preparations for this year's hurricane season.  Before the first storm threatens.
Last September, 5 days before Irma's landfall in Florida, there wasn't a flashlight, battery, bottle of water, or NWS weather radio to be found on any store shelves where I live
As a result, tens of thousands of people went through the storm - and days without power - unprepared.  While for most it was more a matter of discomfort than of safety, Florida got very lucky with Irma.
It could have been much, much worse. And in parts of Texas, and most of Puerto Rico, it was.
Whether you live in `Hurricane Country' or not, if a disaster struck your community today, do you already have?

  • A battery operated NWS Emergency Radio to find out what was going on, and to get vital instructions from emergency officials
  • A decent first-aid kit, so that you can treat injuries
  • Enough non-perishable food and water on hand to feed and hydrate your family (including pets) for the duration
  • A way to provide light when the grid is down.
  • A way to cook safely without electricity
  • A way to purify or filter water
  • A way to stay cool (fans) or warm when the power is out.
  • A small supply of cash to use in case credit/debit machines are not working 
  • An emergency plan, including meeting places, emergency out-of-state contact numbers, a disaster buddy,  and in case you must evacuate, a bug-out bag and a predetermined place to go. 
  • Spare supply of essential prescription medicines that you or your family may need
  • A way to entertain yourself, or your kids, during a prolonged blackout
If your answer is `no’, you have some work to do.  A good place to get started is by visiting Ready.gov.

You may also wish to revisit some of my preparedness blogs:

When 72 Hours Isn’t Enough

In An Emergency, Who Has Your Back?

#NatlPrep: The Gift Of Preparedness 2017

ESA Epidemiological Update: HPAI Clade Viruses in Europe as of 3rd May 2018

HPAI H5N6  in Europe from 1st October 2017 to 3rd May 2018


While reports of HPAI this past winter in Europe have been subdued compared to the previous year's H5N8 record epizootic, a newly reassorted H5N6 virus did arrive last December, and a smattering of H5N8 cases have been reported.
As we've discussed previously, a major bird flu season is generally followed by one or more less severe years (see chart below), and so this recent lull is not unprecedented.

We get our most detailed updates on Europe's avian flu situation from the UK's DEFRA (see April's UK DEFRA: Update On H5N6 HPAI UK/Europe & H5N8 HPAI In Europe) and France's ESA Epidemiosurveillance Santé Animale (see ESA Epidemiological Update: Global Circulation Of Avian Flu).

Today (May 22nd) the ESA has published a new report, covering the spread of Clade viruses over this past winter (Oct 1st - May 3rd) in Europe.  I've included some translated excerpts, but you'll want to follow the link to read the full report.

Epidemiological situation of HPAI viruses from clade in Europe as of 3rd May 2018

Submitted by Alizé MERCIER on 22. May 2018 - 11:40.
For the Epidemic Intelligence team (VSI) (in alphabetical order): Anne Bronner (DGAL), Didier Calavas (Anses), Julien Cauchard (Anses), Sylvain Falala (Inra), Alizé Mercier (Cirad)

For the National Hunting and Wildlife Agency (ONCFS): Anne Van De Wiele
Corresponding author: alize.mercier@cirad.fr

Sources: Data updated on 3rd May 2018 (included) ADNS/FAO/OIE, DGAL (General Directorate of Food – French Ministry of Agriculture), ProMED

Since the last situation report on 26th March 2018, the highly pathogenic avian influenza (HPAI) virus of subtype H5N6 has been reported for the first time in Slovakia on 28th March in wild birds (the virus was detected in a black-headed gull (Chroicocephalus ridibundus) among five birds found dead), and in Finland with two cases reported on 3rd and 24th April in white-tailed eagles (Haliaeetus albicilla).

The H5N6 virus was also identified in wild birds in other countries:

  • Denmark: 22 new reports involving five white-tailed eagles (four reports on 23/04 and one report on 30/04), ten common buzzards (Buteo buteo) (nine reports on 24/04 and one report on 12/04), two mute swans (Cygnus olor) (reports on 23/04 and 24/04), a great cormorant (Phalacrocorax carbo) (report on 23/04), a herring gull (Larus argentus) (report on 23/04), a black-headed gull (report on 23/04), and two hooded-crows (Larus argentus) (reports on 12/04),
  • Germany: a case in a white-tailed eagle (report on 30/04),
  • Sweden: cases in two white-tailed eagles (reports on 09/04 and 26/04), in a common buzzard (report on 26/04), and in a Northern goshawk (Accipiter gentilis) (report on 26/04),
  • United-Kingdom: a case in two common buzzards (report on 20/04), and
  • The Netherlands: a case in a common buzzard (report on 28/03).
The H5N6 virus has also been notified in captive wild birds with a case reported in Sweden on 9th April in a non-commercial holding of 105 birds (species not mentioned).

The H5N8 virus continues to circulate in poultry farms:

  • Italy: an outbreak reported in a fattening turkey farm (report on 28/03), and
  • Bulgaria: four outbreaks reported in three duck farms (reports on 05/04 and 24/04) and in a State hunting reserve (report on 18/04).
Bulgaria has also reported four outbreaks of H5Nx in duck farms on 5th and 25th April.

From 1st October 2017 to 3rd May 2018 (included), a total of 145 outbreaks of HPAI H5 (including 60 outbreaks of H5N8) were notified in twelve European countries: Bulgaria, Cyprus, Denmark, Germany, Ireland, Italy, the Netherlands, Sweden, Switzerland, the United-Kingdom, Finland and Slovakia (Table 1, Figures 1&2). Two serotypes were identified: H5N6 (Figure 1) and H5N8 (Figure 2).

An H5N2 virus detected in Russia
On 29th December 2017, Russia reported an outbreak of HPAI H5N2 in a poultry farm of more than 660 000 birds, in the region of Kostroma in the Northeast of Moscow (OIE report 29/12/2017). This outbreak was initially notified as H5N8 three days prior.

This is the first report of HPAI H5N2 virus in Russia and the last outbreak of HPAI H5N2 reported in Europe dates back to January 2017 with three outbreaks reported in poultry farms in France.

Regarding the origin of this virus, two hypotheses can be formulated:
  • the mutation of a LP H5N2 virus in domestic birds, into a HP virus (as was the case in 2015 with H7N7 in the United Kingdom and Germany, or with H5N1 and H5N2 in France),
  • a reassortment between HP H5N8 which circulated in Europe in 2016-2017 with a LP Eurasian strain, as for the H5N6 virus currently circulating in Europe. Indeed, viruses from clade have a strong mutation potential, as illustrated by the emergence of H5N6 and H5N5 viruses following the circulation of H5N8 in Europe in 2016-2017.
Whatever the case may be, further analyses are needed to identify the origin, the link and the genetic composition of these new viruses, and the evolution of the epidemiological situation in Europe should be closely monitored.
 (Continue . . . )

Monday, May 21, 2018

Indian Government Responds To Reported Nipah Outbreak In Kerala



The Nipah virus - normally carried by fruit bats common to S.E. Asia - was only first identified 20 years ago after an outbreak in Malaysia, which spread from bat to pigs - and then from pigs to humans - eventually infecting at least 265 people, killing 105 (see Lessons from the Nipah virus outbreak in Malaysia).

Similar to Australia's Hendra virus - Nipah - because of its high mortality and (limited) human-to-human transmissibility - has garnered a reputation among researchers as having at least some pandemic or bio-terrorism potential.
  • In Steven Soderbergh's 2011 pandemic thriller `Contagion’, technical advisor Ian Lipkin - director of Columbia University’s Center for Infection and Immunity in New York - painstakingly created a fictional MEV-1 pandemic virus based on a mutated Nipah virus. 
  •  In 2015's Blue Ribbon Study Panel Report on Biodefense a bi-partisan panel described a fictional biological attack on Washington D.C.  using a genetically engineered Nipah virus as part of their presentation. 
  • Just last week, in the Johns Hopkins Clade X exercise, a genetically altered Nipah virus (spliced onto a parainfluenza backbone) was the cause of their fictional pandemic.  
  • And earlier this year, in WHO List Of Blueprint Priority Diseases, we saw Nipah and Henipaviral diseases listed among the 8 viral threats in need of urgent accelerated research and development.    
Overnight, India media (and now Western media) have been reporting on an outbreak of Nipah in Kozhikode, in India's southern Kerala state (see Crof's blog Kozhikode: 11 die of suspected Nipah virus infection; medical officials say no need to panic).

While the Indian media is known for its hyperbole, and the exact number of cases and/or deaths vary between accounts - other reports - such as the BBC's  Deadly Nipah virus claims victims in India at least confirm the main points of the story.

The only official statement I've found (the MOH website remains typically silent) has been the following brief press release from the Press Information bureau.
Ministry of Health and Family Welfare           21-May, 2018 13:51 IST
Shri J P Nadda assures all support to Kerala Government to manage Nipah Virus; Sends a multi-disciplinary Central team to investigate the outbreak

In view of the rising number of cases and reported deaths due to Nipah Virus in Kozhikode, Kerala, Shri J P Nadda, Union Minister of Health and Family Welfare has assured all support to the Kerala Government and has directed a multi-disciplinary Central team from National Centre for Disease Control to immediately visit the district, and assist the State and closely monitor the situation. The team will reach Kerala today.

“We are closely monitoring the situation. I have spoken to Shri Alphons and Smt K Shailaja, Health Minister, Kerala and assured them all support of the Central government. I have also dispatched a Central team to assist the State government and initiate required steps,” the Union Health Minister said in a statement from Geneva.

On the directions of the Health Minister, Smt. Preeti Sudan, Secretary (HFW) has also spoken to the Principal Health Secretary of Kerala and reviewed the situation.

The Central team includes Dr Sujeet K Singh, Director, National Centre for Disease Control, Dr S K Jain, Head Epidemiology, NCDC, Dr P Ravindran, Director, Emergency Medical Relief (EMR), Dr Naveen Gupta, Head Zoonosis, NCDC along with two clinicians and one expert from Ministry of Animal Husbandry.
Over the past decade nearly all of the reported Nipah outbreaks have come out of Bangladesh, often linked to date palm sap collection (see Bangladesh: Nipah Update).
Fruit bats of the Pteropodidae family have a preference for roosting in the tops of trees rather than caves, which allows them to contaminate date juice collection jars with their virus laden urine and feces
Once infected via a zoonotic exposure, humans can transmit the virus on to others, albeit not terribly efficiently (see EID Journal Person-to-Person Transmission of Nipah Virus in a Bangladeshi Community).

While outbreaks of Nipah have tended to be limited in size, we'll be following the events in Kozhikode (pop. 550,000) closely, as our knowledge of the virus is limited as well.

Stay tuned. 

Sunday, May 20, 2018

J.I.D.: Population Serologic Immunity To H2N2 For Pandemic Risk Assessment


While we watch H7N9 and an assortment of avian H5 viruses for signs of developing pandemic capabilities, the known history of influenza pandemics going back more than 125 years is of a repeating pattern of H1, H2, and H3 viruses;  H2, H3, H1, H2, H3, H1 . . . .
Meaning - if that pattern were to persist - we should be looking for an H2 virus as our next pandemic contender.
Patterns - particularly short term patterns (and 130 years of influenza history qualifies as `short term') - tend to deceive, and there are also a number of non-influenza pandemic contenders (MERS, SARS, etc.) in the wings.  
So I wouldn't bet the farm on any one pathogen winning the pandemic sweepstakes.
But H2 influenza does remain in the back of a lot of researcher's heads as a likely candidate.  H2 appears to have produced a pandemic in the early to mid  1890s, and returned again in 1957 - roughly 60 years later.

Similarly, H3 viruses unleashed two pandemics (1900 and 1968) roughly 68 years apart, while H1N1 causing the great 1918 pandemic only to return in the pseudo-pandemic of 1977, 59 years later.

We are now 60 years since H2N2 last emerged as a pandemic strain.  It disappeared from the human population 11 years later (1968), and so anyone born after that has never been exposed to it.

But, as 2009's H1N1 pandemic showed us, previous exposure to an H1N1 virus didn't guarantee immunity, and so those of us over 50 could easily be affected as well.
Add in enough antigenic drift, and any acquired immunity can be overrun.
H2N2 (and other H2 subtypes) have continued to be reported in the wild - in both swine and wild birds - making its return, if not assured, at least possible.

In 2011, after the furor over the 2009 H1N1 pandemic had finally died down, some researchers suggested it might make sense to add an H2N2 component to the seasonal vaccine to head off the `next' pandemic (see Nature: A Preemptive H2N2 Vaccine Strike?).
While it sparked some academic discussions, this controversial proposal never went anywhere, the consensus being it was impossible to pick the `next' pandemic subtype with any confidence. 
In 2012, in H2N2: What Went Around, Could Come Around Again, we looked at a study conducted by scientists working at St. Jude Children's Research Hospital - published in the Journal of Virology - that concluded that H2N2 could well pose a threat to humanity once again.
A press release on this research warned:
1950s pandemic influenza virus remains a health threat, particularly to those under 50
St. Jude Children's Research Hospital scientists report that avian H2N2 influenza A viruses related to 1957-1958 pandemic infect human cells and spread among ferrets; may aid identification of emerging threats.
In 2015, we saw (so far, failed) predictions from Russian virologist Vladimir Blinov (see When H2N2 Predictions Go Viral) that H2N2 would return in 2017 as a pandemic strain.

Also in 2015, we saw a study published in The Journal Of Veterinary Medical Science, which detailed the finding of H2N2 in Siberian Muskrats (see H2N2: Everything Old Is Flu Again), perhaps sparking concerns over its return in Russia's virological circles. 
Should H2N2 re-emerge, it would find a largely susceptible global population, with some countries - particularly in the developing world, where populations run much younger - at even greater risk.
Providing us with a snapshot of the likely immunity (or lack, thereof) to H2N2 in the United States and Hong Kong, we have a new study published in the Journal of Infectious Diseases which finds the remaining vestiges of community immunity insufficient to block the pandemic spread of the virus.

First the link and abstract, after which I'll return with a postscript.

Population Serologic Immunity to human and avian H2N2 viruses in the United States and Hong Kong for Pandemic Risk Assessment
T M Babu R Perera J T Wu T Fitzgerald C Nolan B J Cowling S Krauss J T Treanor M Peiris

The Journal of Infectious Diseases, jiy291, https://doi.org/10.1093/infdis/jiy291

Published: 12 May 2018

Influenza A pandemics cause significant mortality and morbidity. H2N2 viruses have caused prior pandemic, and are circulating in avian reservoirs. The age-related frequency of current population immunity to H2 viruses was evaluated.


Hemagglutinin inhibition (HAI) assays against historical human and recent avian influenza A (H2N2) viruses were performed across age groups in Rochester, NY and Hong Kong, China. The impact of existing cross-reactive HAI immunity on the effective reproductive number(R) was modeled.


150 individual sera from Rochester and 295 from Hong Kong were included. 85% born in Rochester and Hong Kong before 1968 had HAI titers >1:40 against A/Singapore/1/57, and over 50% had titers >1:40 against A/Berkeley/1/68.
The frequency of titers ≥1:40 to avian H2N2 A/Mallard/England/727/06 and A/Mallard/Netherlands/14/07 in subjects born before 1957 was 62% and 24%.

There were no H2 HAI titers >1:40 in individuals born after 1968. These levels of seroprevalence reduce the initial R of A/Singapore/1/1957 or A/Berkeley/1/68 by 15%-20%. A basic reproductive number (R0) of the emerging transmissible virus less than 1.2 predicts a preventable pandemic.

Population immunity to H2 viruses is insufficient to block epidemic spread of H2 virus. An H2N2 pandemic would have lower impact in those born before 1968.

In 1977, a year after the feared H1N1 `swine flu' pandemic failed to materialize (see my account Deja Flu, All Over Again),  H1N1 did return after a 20 year absence, in what was dubbed the `Russian Flu' (suspected to have escaped from a Russian or Chinese lab). 
Those under 20 we're hardest hit. I was luckily 23 at the time.
As a young paramedic, it was my first `epidemic experience', and while far from a pandemic, it did slam local hospitals hard, force some ER closures, hospitals ran out of bed, and we dealt with constant ambulance diversions.
While the impact was limited and most patients recovered, in some people’s books 1977 qualifies as a `pseudo-pandemic’ year . . . at least for kids. 
H2N2 has lain dormant for far longer, and those born after 1968 appear to have little or no immunity to the influenza viruses that circulated in the mid and early 1960s.

Credit CIA World Fact Book

With the median global age just over 30, and nearly 80% of the world's population under the age of 50, should H2N2 return, it would likely find few immunological impediments to its spread.

While H7N9 or H5N6 might produce a much higher mortality rate, H2N2 has a long track record of successfully sparking pandemics, making it a virus we definitely want to watch.

Saturday, May 19, 2018

APHIS: USDA Confirms Virulent Newcastle Disease In Backyard Flock - California

Credit Iowa State Center For Food Security & Public Health


Although it poses only a minor threat to human health, Virulent Newcastle Disease can be up to 100% fatal in poultry, and is a serious threat to poultry interests world wide. In humans, the virus generally causes mild flu-like illness and/or conjunctivitis.

Yesterday the California Dept. of Food & Agriculture announced.

May 18, 2018: Virulent Newcastle Disease Confirmed in a Backyard Chicken Flock in Los Angeles County

The California Department of Food and Agriculture (CDFA) has detected virulent Newcastle disease in a small flock of backyard exhibition chickens in Los Angeles County. The detection has been confirmed by the United States Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS). This is the first case of virulent Newcastle disease, previously referred to as exotic Newcastle disease, in the U.S. since 2003.

CDFA is working with federal and local partners as well as poultry owners to respond to the finding. State officials have quarantined potentially exposed birds and are testing for the disease.

It is essential that all poultry owners follow good biosecurity practices to help protect their birds from infectious diseases. These include simple steps like washing hands and scrubbing boots before and after entering a poultry area; cleaning and disinfecting tires and equipment before moving them off the property; and isolating any birds returning from shows for 30 days before placing them with the rest of the flock. In addition to practicing good biosecurity, all bird owners should report sick birds or unusual bird deaths
through California's Sick Bird Hotline at 866-922-BIRD (2473).

The last poultry outbreak in the United States was reported in 2003 (described below), although sporadic detections in wild birds have continued around the country. This also from the California Dept. of Food & Agriculture.
The 2002-03 END outbreak, originally confirmed in backyard poultry in Southern California, spread to commercial poultry operations in California and backyard poultry in Arizona, Nevada and Texas.  The Governor of California declared a State of Emergency, the Secretary of the United States Department of Agriculture (USDA) declared an Extraordinary Emergency, and local emergencies were declared in San Diego, Riverside, Los Angeles, and San Bernardino Counties.  A USDA and the California Department of Food and Agriculture (CDFA) Task Force was formed that involved over 7,000 individuals rotating in and out over the course of the outbreak.  Trade restrictions resulting from the disease had negative impacts on California and U.S. poultry and egg producers.  The outbreak, from discovery to eradication, lasted eleven months.  The outbreak response led to the depopulation of 3.16 million birds at a cost of $161 million.
In 1971, an outbreak that began in Southern California led to the culling of 12 million birds and a loss of tens of millions of dollars.

Yesterday APHIS/USDA also released the following statement.

USDA Confirms Virulent Newcastle Disease in a Backyard Chicken Flock in California, Not a Food Safety Concern

Contacts: Joelle Hayden  
Lyndsay Cole

WASHINGTON, May 18, 2018 - The United States Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed the presence of virulent Newcastle disease in a small flock of backyard exhibition chickens in Los Angeles County, California. It is important to note that the presence of the disease is not a food safety concern. This is the first case of virulent Newcastle disease, previously referred to as exotic Newcastle disease, in the U.S. since 2003.

No human cases of Newcastle disease have ever occurred from eating poultry products. Properly cooked poultry products are safe to eat.  In very rare instances people working directly with sick birds can become infected. Symptoms are usually very mild, and limited to conjunctivitis and/or influenza-like symptoms. Infection is easily prevented by using standard personal protective equipment.  

APHIS is working closely with the California Department of Food and Agriculture to respond to the finding. Federal and State partners are also conducting additional surveillance and testing in the area.  

It is essential that all bird owners follow good biosecurity practices to help protect their birds from infectious diseases.  These include simple steps like washing hands and scrubbing boots before and after entering a poultry area; cleaning and disinfecting tires and equipment before moving them off the property; and isolating any birds returning from shows for 30 days before placing them with the rest of the flock.

In addition to practicing good biosecurity, all bird owners should report sick birds or unusual bird deaths to State/Federal officials, either through their state veterinarian or through USDA’s toll-free number at 1-866-536-7593.  Additional information on biosecurity for backyard flocks can be found at Biosecurity for Birds website. 

Additional background

Virulent Newcastle disease is a contagious and fatal viral disease affecting the respiratory, nervous and digestive systems of birds and poultry. The disease is so virulent that many birds and poultry die without showing any clinical signs. A death rate of almost 100 percent can occur in unvaccinated poultry flocks. Virulent Newcastle disease can infect and cause death even in vaccinated poultry.

Clinical signs of virulent Newcastle disease include: sudden death and increased death loss in the flock; sneezing; gasping for air; nasal discharge; coughing; greenish, watery diarrhea; decreased activity; tremors; drooping wings; twisting of the head and neck; circling; complete stiffness; and swelling around the eyes and neck.  Images of some of these signs are available here.
While this is hopefully just an isolated incident, this outbreak reinforces the importance of maintaining proper biosecurity in all agricultural operations, and reminds us that exotic animal diseases - even those absent from the U.S. for 15 years - can always come back.

Friday, May 18, 2018

It's Naegleria Season



The Memorial Day Weekend traditionally signals the start of the long awaited summer swimming season - but with that comes risks - including the dangers of rip currents (see How Not To Be Swept Away This Summer), potentially serious salt water skin infections (see Vulnerable To Vibrio), and an extraordinarily rare, but often fatal, brain infection from an amoebic parasite called Naegleria fowleri.
Dubbed the `brain eating amoeba' by the press - this infection is called PAM (Primary amebic meningoencephalitis) - and occurs when the amoeba enters the brain through the nasal passages, usually due to the forceful aspiration of contaminated water into the nose.  
Although we generally only hear about 3 or 4 cases in the United States each summer, last December in EID Journal: Estimation of Undiagnosed Naegleria fowleri (PAM), United States, a research letter written by epidemiologists from the CDC estimated the yearly number PAM cases in the United States probably averages closer to 16 (8 males, 8 females).
Meaning that right now, 70%-80% likely go unrecognized.
Until a few years ago, nearly all of the Naegleria infections reported in the United States were linked to swimming in warm, stagnant freshwater ponds and lakes (see Naegleria: Rare, 99% Fatal & Preventable), making this pretty much a summer time threat.

In 2011, however,  we saw two cases reported in Neti pot users from Louisiana, prompting the Louisiana Health Department to recommend that people `use distilled, sterile or previously boiled water to make up the irrigation solution’ (see Neti Pots & Naegleria Fowleri).

While  rare in the United States, every year Pakistan reports a dozen or more infections from this `killer amoeba’, as chlorination of their water supplies is often inadequate, and for many, nasal ablutions are part of their daily ritual.

Two years ago we looked at an MMWR: Epidemiological Investigation Into A Case Of Primary Amebic Meningoencephalitis  in California which suggested a poorly chlorinated spring-fed swimming pool was the likely source of infection and death of a 21 year old woman. 
This was also an unusual finding, and furthers the recent pattern of seeing PAM cases arise from atypical settings (Northern states, via neti pots and municipal water supplies, etc.) in the United States.
Up until a recently, infection with Naegleria fowleri was universally fatal, but in 2013 an investigational drug called miltefosine was used successfully for the first time to treat the infection.  Early diagnosis, and administration of this drug, are crucial however.
Even with this new drug, prevention is the key to saving lives, and leading the charge in educating the public is http://amoeba-season.com/, a USF Philip T. Gompf Memorial Fund project, which was set up by a pair of Florida doctors who tragically lost their 10 year-old son to this parasite in 2009.
As a thermophilic (heat-loving), free-living amoeba, it is hardly surprising to see that Florida and Texas lead the nation in cases over the past three decades, although infections have occurred as far north as Minnesota. 

Credit Florida DOH
The State of Florida's Primary Amebic Meningoencephalitis (PAM) website recommends:
The only known way to prevent Naegleria fowleri infections is to refrain from water-related activities. However, some common-sense measures that might reduce risk by limiting the chance of contaminated water going up the nose include:
  • Avoiding water-related activities in bodies of warm freshwater, hot springs, and thermally-polluted water such as water around power plants.
  • Avoiding water-related activities in warm freshwater during periods of high water temperature and low water levels.
  • Holding the nose shut or using nose clips when taking part in water-related activities in bodies of warm freshwater such as lakes, rivers, or hot springs. 
  • Avoiding digging or stirring up sediment while taking part in water-related activities in shallow, warm freshwater areas. 
Recreational water users should assume that there is always a low-level of risk associated with entering all warm fresh water in southern tier states. Because the location and number of ameba in the water can vary a lot over time, posting signs is unlikely to be an effective way to prevent infections. In addition, posting signs on only some fresh water bodies might create a misconception that bodies of water that are not posted are Naegleria-free.
Information about the risks associated with Naegleria fowleri infection should be included in public health messages discussing general issues of recreational water safety and risk.
When preparing solutions of tap water for sinus irrigation, the user should use tap water previously boiled for 1 minute (at elevations above 6,500 feet, boil for 3 minutes) and left to cool, use water filtered with an absolute filter pore size of 1 micron or smaller, or use clearly marked distilled or sterile water in the irrigation device. Rinse the irrigation device after each use with water that has been previously boiled, filtered, distilled, or sterilized and leave the device open to air dry completely.
For some of my earlier blogs on Naegleria you may wish to revisit:

A Reminder About Naegleria
Reminder: COCA Call Today On Naegleria Fowleri & Cryptosporidium
MMWR: CDC Imports Investigational Drug For Amoebic Infections