Friday, July 20, 2018

Russia: Rosselkhoznador Statement On Prevention & Control Of Avian Influenza

June 30th Rosselkhoznador Update
















#13,416


Although the Russian language media continues to report on fresh HPAI H5 outbreaks in Western Russia, we've seen surprisingly little mention of Russia's avian flu epizootic by their (local or central) Rosselkhoznador Federal Service for Veterinary and Phytosanitary Surveillance.
The most recent update on the central Rosselkhoznador avian flu site is now 3 weeks old.
Six weekly reports have been submitted to the OIE (see below), summarizing more than 50 outbreaks since early June, across at least 9 oblasts.

Related reports Immediate notification (13/06/2018) 
Follow-up report No. 1 (20/06/2018)
Follow-up report No. 2 (27/06/2018)
Follow-up report No. 3 (04/07/2018)
Follow-up report No. 4 (11/07/2018)
Follow-up report No. 5 (18/07/2018)
   Yesterday's OIE Update (No.5) lists 13 new outbreaks across 4 oblasts, with 7 of those reported from the Chuvash Republic.
While HPAI H5N8 is strongly suspected, except for a DEFRA report citing H5N8 last week, we've only seen Russia's outbreak described as HPAI H5.
Below you'll find the local statement from the Chuvash Republic.

       (Translated)
On activities for prevention and control of avian influenza in the Chuvash Republic

July 19, 2018


© Central body

Office of Rosselkhoznadzor for Chuvashia and Ulyanovsk Region reported that as of July 18th 2018 on the territory of the Chuvash Republic registered 9 epizootic outbreaks identified disadvantaged 8 points on the highly pathogenic type A subtype H5 bird. Avian influenza is registered in the territory of Batyrevsky, Komsomolsk, Yalchikskogo, Tsivilsky, Ibresinskogo and Krasnochetaysky areas.

Decree of the Head of the Chuvash Republic in all the areas mentioned restrictive measures (quarantine) introduced.

Specialists Gosvetsluzhby Chuvashia, in accordance with the decree of the Cabinet of Ministers of the Chuvash Republic in disadvantaged locations Batyrevsky and Komsomolsk districts organized work for the disposal of poultry of all types and removal of poultry products.

Fixed by Rosselkhoznadzor Office of the Chuvash Republic and the Ulyanovsk region in the endangered zones and surveillance zones are monitored for compliance with the owners of birds animal health rules aimed at protecting places of birds from bringing them into the infectious agent. In cooperation with the specialists of veterinary services districts and heads of rural settlements conducted door-bypass to conduct clinical examination ptitsepogolovya, exercises control over the observance of the birds owners with veterinary and sanitary requirements for the contents of birds and implementation of measures to prevent and control avian influenza.
During the inspection of organized screening of blood samples from the birds for monitoring studies for the presence of avian influenza virus. The samples are sent to study in the laboratory subordinated to the Rosselkhoznadzor (Federal State Budgetary Institution "Tatar MVL" FGBU "ARRIAH") as part of the federal state of epizootic monitoring. Implemented as a detour reservoirs rural settlements endangered zone and the surveillance zone Batyrevsky and Komsomolsk districts, where the presence of waterfowl has been established.

Management professionals conducted explanatory work with the population of the notice of veterinary experts on all cases of sudden mortality or the simultaneous mass disease of birds, their unusual behavior.

During the inspection of violations of veterinary and sanitary requirements for poultry in personal farmsteads of citizens, as well as the free sale of birds and poultry products has been established. The owners provided the poultry content in conditions excluding contact between other species of birds, including wild waterfowl. In total, inspectors visited 34 court in 9 localities Batyrevsky and Komsomolsk districts, conducted clinical examination of 827 heads of birds, in order to monitor the selected 54 samples, which is 7%.

While avian flu outbreaks in Western Europe are currently at their summer nadir, migratory birds following the Black Sea/Mediterranean Flyway will be crossing Western Russia on their southbound trek to Europe, the Middle East and Africa this fall.

As we've seen in the past, they can sometimes pick up avian flu viruses along the way, and deposit them further down the line.




Two years ago, migratory birds delivered a freshly reassorted HPAI H5N8 virus to Germany, which quickly sparked Europe's largest avian epizootic on record, and spread quickly to the Middle East and Africa.  

Which is why we're eager to get more details on the virus currently plaguing Western Russia's poultry industry. 
 

California: 24 New Outbreaks of VND In Poultry Over Last 10 Days

CDFA Quarantine Order





















#13,415


Eleven days ago (July 9th) California's Department of Food & Agriculture issued an emergency quarantine order (see California: 11 New Outbreaks of VND In Poultry - Quarantine Ordered In 2 Counties) after 39 outbreaks of Virulent Newcastle Disease in backyard exhibition poultry had been reported in Southern California over the previous 7 weeks.
In the 10 days since that last report, 24 additional outbreaks (ttl=63) have been reported from 3 counties (San Bernardino, Riverside & Los Angeles) - an increase of 60% in less than two weeks. 
While the first outbreak (May 17th) was reported from Los Angeles County, since then all other cases had been reported from either San Bernardino or Riverside County.

Yesterday, that streak ended when the CDFA reported two new outbreaks in Los Angeles County.
July 19, 2018: Additional Cases of Virulent Newcastle Disease in Backyard Birds in Multiple Counties

Bird owners in Southern California are responding to outreach provided over the past several days related to virulent Newcastle disease (VND), and have reported sick birds. Samples from the flocks, which experienced increased mortality, were tested at the California Animal Health & Food Safety Laboratory System (CAHFS). The United States Department of Agriculture (USDA) Animal and Plant Health Inspection Services (APHIS) National Veterinary Services Laboratories (NVSL) in Ames, Iowa, confirms all findings.
Five additional cases of virulent Newcastle disease in backyard chickens in California have been confirmed- two in Los Angeles County, one in Riverside County, and two in San Bernardino County. For a list of cases visit the USDA website at: https://www.aphis.usda.gov/animalhealth/vnd
The USDA's summary follows.

Virulent Newcastle Disease

Last Modified: Jul 19, 2018
Virulent Newcastle Disease (vND), formerly known as Exotic 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.

vND is not a food safety concern. 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 with mild symptoms.
vND has not been found in commercial poultry in the U.S. since 2003.
Since May 18, USDA has confirmed 62 cases of vND in backyard birds in California, 54 in San Bernardino County, 5 in Riverside County and 3 in Los Angeles County:
        (Continue . . . .)



As mentioned above, there is a slight risk of human infection, but illness is generally mild and usually presents as conjunctivitis. The real threat is to the poultry industry, should the virus find its way again into commercial flocks. 

According to the California Dept. of Food & Agriculture, the last outbreak in commercial poultry back in 2003 led to the depopulation of 3.16 million birds at a cost of $161 million.  Prior to that, in 1971, an outbreak in Southern California led the culling of 12 million birds.
From the recently updated USDA Fact sheet on VND:

Know the Signs of Virulent Newcastle Disease
If you see any of the following signs in your birds, they could be sick and should be checked out:
  • Sudden death and increased death loss in flock;
  • Sneezing, gasping for air, nasal discharge, coughing;
  • Greenish, watery diarrhea;
  • Decreased activity, tremors, drooping wings, twisting of head and neck, circling,complete stiffness; and
  • Swelling around the eyes and neck.
Report Sick Birds ASAP
If your birds are sick or dying, report it right away! Early detection and testing of possible cases of virulent Newcastle disease is critical to preventing a large-scale outbreak.
Contact your agricultural extension office/agent, local veterinarian, local animal health diagnostic laboratory, or the State veterinarian. Or, call USDA toll free at 1-866-536-7593, and we’ll put you in touch with a local contact. There’s no charge for a disease investigation.
How Virulent Newcastle Disease Spreads
Virulent Newcastle disease spreads when healthy birds come in direct contact with bodily fluids from sick birds. The disease affects almost all birds and poultry, even vaccinated poultry. The virus can travel on manure, egg flats, crates, other farming materials or equipment, and people who have picked up the virus on their clothing, shoes, or hands.



Thursday, July 19, 2018

Emerg. Microbes & Infect.: Low Zoonotic Potential Of Clade 2.3.4.4B H5N8 Virus

Asian H5 Evolution Through 2011



















#13,414

While we tend to talk about specific subtypes of influenza (H5N1, H5N8, H7N9, H3N2, etc.) as if they were a single entity, in truth each subtype can contain multiple clades, and within each of these clades there can be numerous subclades, running several layers deep (see H5N1 chart above).
Over time, the complexity and diversity of any successful virus increases, although many of these variants fade away, unable to compete with more biologically fit versions.
Drilling down even deeper, these subclades can be further divided into groups (A, B, C, etc.), - and if that isn't enough complexity for you - there can be significant genetic variation within each of these individual subclades/groups.

Not surprisingly, there can be big differences in the behavior - including the zoonotic potential - of different variants of the same subtype (see 2012's Differences In Virulence Between Closely Related H5N1 Strains).
This likely explains why some countries - like Egypt, Indonesia, and Vietnam - have reported a large number of human H5N1 infections - while other countries where the virus has also circulated have reported few or none.
The evolutionary chart above only deals with H5N1, but since 2011, several new HPAI H5 subtypes - descendants of H5N1 - have emerged, including H5N6 and H5N8.
And like H5N1 before it, these subtypes are building an impressive inventory of genetic variants. 
In 2014 a clade 2.3.4.4A  H5N8 virus - which initially emerged in Chinese poultry - spread like wildfire through South Korea's poultry industry.  Ten months later, it winged its way to North America - where it sparked the biggest avian epizootic in American history.  The virus also made a brief appearance in Europe.
Luckily, we saw no reports of human infection with this new subtype, although South Korea reported a number of exposed dogs developed antibodies  (see MAFRA: H5N8 Antibodies Detected In South Korean Dogs (Again)).
At roughly the same time, a new clade 2.3.4.4.C H5N6 virus appeared in China, Vietnam, and Laos, but unlike its H5N8 cousin, this virus has managed to jump to at least 16 people in China, killing 12 of them.

By the summer of 2015, the H5N8 virus had mysteriously vanished in North America, and it did not return for the winter of 2015-16 (see PNAS: The Enigma Of Disappearing HPAI H5 In North American Migratory Waterfowl). It was also a no show in Europe.

But the following fall (2017), a new - reassorted - 2.3.4.4 group B virus turned up in Germany, and rapidly spread across Europe, and into the Middle East and Africa (see EID Journal: Reassorted HPAI H5N8 Clade 2.3.4.4. - Germany 2016).
This group B version of clade 2.3.4.4. H5N8 virus was much more virulent in birds, spread faster and farther than any HPAI H5 virus we'd seen before, spawned new (H5N5 & H5N6 subtypes) and sparked the biggest epizootic in European history.
While we've seen no reports of human infection with either group A or group B clade 2.3.4.4. H5N8 viruses, we've seen cautionary reports suggesting the potential for zoonotic transmission remains.
J Vet Sci: Evolution, Global Spread, And Pathogenicity Of HPAI H5Nx Clade 2.3.4.4 
Study: Virulence Of HPAI H5N8 Enhanced By 2 Amino Acid Substitutions

Sci Rpts: H5N8 - Rapid Acquisition of Virulence Markers After Serial Passage In Mice
J. Virulence : Altered Virulence Of (HPAI) H5N8 Reassortant Viruses In Mammalian Models

Today we've a new study, published in Emerging Microbes and Infections, which pretty much confirms what we've observed over the past couple of years, finding a low zoonotic potential for clade 2.3.4.4.B H5N8 viruses.

It's a long, and detailed open-access paper, and so I've only included the abstract and a snippet from the discussion section. Follow the link to read it in its entirety, after which I'll return with a postscript.

A novel European H5N8 influenza A virus has increased virulence in ducks but low zoonotic potential

Christian Grund, Donata Hoffmann, Reiner Ulrich, Mahmoud Naguib, Jan Schinköthe, Bernd Hoffmann, Timm Harder, Sandra Saenger, Katja Zscheppang, Mario Tönnies, Stefan Hippenstiel, Andreas Hocke, Thorsten Wolff & Martin Beer
Emerging Microbes & Infections volume 7, Article number: 132 (2018)

Abstract


We investigated in a unique setup of animal models and a human lung explant culture biological properties, including zoonotic potential, of a representative 2016 highly pathogenic avian influenza virus (HPAIV) H5N8, clade 2.3.4.4 group B (H5N8B), that spread rapidly in a huge and ongoing outbreak series in Europe and caused high mortality in waterfowl and domestic birds.

HPAIV H5N8B showed increased virulence with rapid onset of severe disease and mortality in Pekin ducks due to pronounced neuro- and hepatotropism. Cross-species infection was evaluated in mice, ferrets, and in a human lung explant culture model. While the H5N8B isolate was highly virulent for Balb/c mice, virulence and transmissibility were grossly reduced in ferrets, which was mirrored by marginal replication in human lung cultures infected ex vivo.
Our data indicate that the 2016 HPAIV H5N8B is avian-adapted with augmented virulence for waterfowl, but has low zoonotic potential. The here tested combination of animal studies with the inoculation of human explants provides a promising future workflow to evaluate zoonotic potential, mammalian replication competence and avian virulence of HPAIV.

(SNIP)
Overall, high virulence and transmissibility in waterfowl are biological key features of the examined recent HPAIV H5N8 strain of clade 2.3.4.4 B, and judging on the massive mortality in wild birds in Europe, also of further reassortants of this clade. Interestingly, the augmented virulence for Pekin ducks seems to be connected with a higher virulence in Balb/C mice. Thus, the data from the Balb/C mouse model may be predictive for the virulence of HPAIV H5-viruses in ducks.
The results obtained by the ferret infection model were fully consistent with findings in a human lung explant infection model. The summarizing conclusion of a low zoonotic potential of these viruses is further supported by the observation that up to now no human cases have been reported for the H5N8B strain, despite the very broad distribution in the wild bird and poultry populations in many different countries and the re-emergence of the same strain in the last months in several European countries.
        (Continue . . . . )


Given the lack of reported human cases over the past two years, the above findings are hardly unexpected, but this paper does offer a potential framework for making future risk assessments of HPAIV strains.

If the past 20 years are any indication - there's unlikely to be a lack of new, emerging HPAIV strains to evaluate - and we've no guarantees that the next virus to emerge will have the same low zoonotic potential as the H5N8 viruses we've seen to date.

Because influenza, like time, marches on.

Wednesday, July 18, 2018

Sci Rpts: Genetic Characterization & Pathogenic Potential Of Avian H10 Viruses




















#13,413


Among avian flu viruses, subtypes H5 and H7 - due to their 20 year history of producing high human mortality -  tend to garner the bulk of our attention. That said, there are a number of other `second tier' avian viruses that pose a zoonotic threat.
Best known, and discussed often in this blog due to its ability to easily reassort with other viruses, is LPAI H9N2 (see recent overview).
Although the true number of human infections is unknown, at least 3 dozen have been identified over the past 20 years (see FluTrackers Global Cumulative H9N2 Partial Case List 1998-2017).
H9N2 is regarded as having at least some pandemic potential (see CDC IRAT SCORE), and several candidate vaccines have been developed over the years.
But also, in 2013 we saw a woman was hospitalized with mild pneumonia from H6N1 in Taiwan. The following year, in the EID Journal: Seropositivity For H6 Influenza Viruses In China, researchers reported a low - but significant - level of H6 antibodies,  particularly among live bird handlers.

While in 2004 the first known human H10 infections (see Avian Influenza Virus A (H10N7) Circulating among Humans in Egypt) were reported, followed in 2012 by a limited outbreak among workers at a chicken farm in Australia (see in EID Journal: Human Infection With H10N7 Avian Influenza).
Most of these avian flu infections were mild or asymptomatic, and self limiting. Often only producing conjunctivitis or mild flu-like symptoms.
But in late 2013 a new H10N8 virus emerged in Mainland China (see Lancet: Clinical & Epidemiological Characteristics Of A Fatal H10N8 Case) infecting three people, killing at least two.

With both H10N8 and H10N7 now shown capable of infecting humans - albeit with widely varying degrees of severity - H10 is now viewed as deserving of more research and respect.
Yesterday, Scientific Reports published the following characterization report on a number of H10 reassortants (H10N1, H10N6, H10N7 & H10N9) found to be circulating in live poultry markets in Bangladesh.
It's a long, detailed, report and you'll want to read it in its entirety.  First the abstract, then I'll return with a couple of snippets from the body of the study.

Genetic characterization and pathogenic potential of H10 avian influenza viruses isolated from live poultry markets in Bangladesh
Rabeh El-Shesheny,John Franks, Bindumadhav M. Marathe, M. Kamrul Hasan, Mohammed M. Feeroz, Scott Krauss, Peter Vogel, Pamela McKenzie, Richard J. Webby & Robert G. Webster

Scientific Reportsvolume 8, Article number: 10693 (2018) | Download Citation

Abstract

Fatal human cases of avian-origin H10N8 influenza virus infections have raised concern about their potential for human-to-human transmission. H10 subtype avian influenza viruses (AIVs) have been isolated from wild and domestic aquatic birds across Eurasia and North America.

We isolated eight H10 AIVs (four H10N7, two H10N9, one H10N1, and one H10N6) from live poultry markets in Bangladesh. Genetic analyses demonstrated that all eight isolates belong to the Eurasian lineage.

HA phylogenetic and antigenic analyses indicated that two antigenically distinct groups of H10 AIVs are circulating in Bangladeshi live poultry markets.
We evaluated the virulence of four representative H10 AIV strains in DBA/2J mice and found that they replicated efficiently in mice without prior adaptation. Moreover, H10N6 and H10N1 AIVs caused high mortality with systemic dissemination.

These results indicate that H10 AIVs pose a potential threat to human health and the mechanisms of their transmissibility should be elucidated.
        
        (Continue  . . . . )


In the discussion section of the study, the authors (which include both Webby & Webster from St. Jude Children’s Research Hospital) point out the risks of the co-circulation of H9N2 viruses in Bangladesh.

As we've discussed previously (see The Lancet: H9N2’s Role In Evolution Of Novel Avian Influenzas), these ubiquitous (in Asia and increasingly in the Middle East) LPAI viruses have lent their internal genes to some of the most dangerous avian viruses in the wild.
The H9N2 AIV is endemic in Bangladesh21,44,45,46 and has acquired mammalian host–specific mutations in its internal genes, which have been shown to facilitate transmission from avian species to humans44. H9N2 AIVs are significant donors of genetic material to emerging zoonotic viruses such as H5Nx, H7N9, and H10N8 AIVs posing an enormous threat to both human health and poultry industry. The wide circulation of H9N2 AIVs in Bangladeshi LPMs affords H9N2 with more opportunities for reassortment with other AIV subtypes, such as H10 AIVs. 
While the number of reported H10 infected humans has been small, due to a lack of surveillance and testing, it is likely that those numbers under represent reality. 
In 2014's BMC: H10N8 Antibodies In Animal Workers – Guangdong Province, China, we saw evidence suggesting that people may have been infected with the H10N8 virus in China before the first  case was recognized. 
As the following snippet indicates, a similar serological study published in 2010 showed evidence of H10 infection among American turkey farmers.

Transmission of H10 AIVs to humans has resulted in some fatal cases, and serologic evidence indicates that H10 AIVs were previously transmitted among turkey farmers in the United States47.
This should raise concern about the potential for human-to-human transmission of H10 AIVs. Evaluation of the biologic properties of H10 and other subtypes of AIVs circulating in LPMs is essential for understanding the emergence and evolution of these viruses and to reduce their potential pandemic threat to public health.

While we often hear (for good reason) that the H7N9 virus is the top pandemic contender in the wild, the same was being said about H5N1 until an upstart swine-origin H1N1 virus came out of left field and sparked the 2009 pandemic.

Which is why we need to constantly look beyond the obvious pandemic threats, if we hope to have a head's up over what comes down the pike next.


Denmark: HPAI H5N6 Reported In Dead Eider



















#13,412


Although news about HPAI H5N6 in Europe has been pretty much absent for the past couple of months (see latest DEFRA report), and the warmth of summer usually helps to suppress bird flu, we've a new report of the discovery of HPAI H5N6 in a wild bird in Denmark, north of Lolland.
This is the first HPAI detection in Denmark since mid-April - although LPAI H5 was reported in early May - and the 30th positive finding in wild birds of 2018.
This from Denmark's Veterinary and Food Administration, after which, I return with a bit more.

Avian influenza - current situation

There are 16 July detected highly pathogenic bird flu in a dead wild bird found Smålandshavet north of Lolland.

wild birds

Discovery of bird flu in wild birds

National Veterinary Institute have 16 July 2018 identified highly pathogenic avian influenza type H5N6 in a dead eider. Eider was found with several other dead birds Smålandshavet north of Lolland.
It is the first time since mid-April that gathered a dead wild bird in nature, which turns out to be infected with highly pathogenic avian influenza. The total number of cases this year has now reached 30. 
Previously, it has been especially sea eagles and buzzards, which are found to be infected, but the infection is also found in other species of birds such as crows, gulls, swans and one cormorant. The findings are gradually made many places in Denmark, including in North Jutland, Zealand, Lolland, Falster, Funen, Bornholm and Als.

The first findings of highly pathogenic avian influenza H5N6 was done in early March in an eagle found near Slagelse. For details about findings see map of Denmark here .

Sporadic finds of bird flu is not surprising, but usually it is rare to find highly pathogenic bird flu in mid summer. There have been no reports of human infection with the avian influenza virus type.
 
While H5N6  hasn't sparked the kind of large scale avian epizootic we saw over the winter of 2016-17 with H5N8 - both viruses have shown unusual persistence, and an expanded host range - in wild birds.
And that is a fairly recent change.
A 2015 study (see PNAS: The Enigma Of Disappearing HPAI H5 In North American Migratory Waterfowl) - conducted after the 2014-15 North American HPAI H5 epizootic - concluded that while migratory waterfowl can briefly carry HPAI H5, they were not a good long-term reservoir for highly pathogenic avian flu viruses.
HPAI viruses appeared to burn out fairly quickly in aquatic waterfowl populations - likely due to their long standing immunity to LPAI viruses - and would therefore have to be reintroduced periodically.
That changed in the fall of 2016 when H5N8 returned to Europe and brought with it a number of genetic and behavioral changes attributed to a reassortment event that likely took place sometime in the spring of 2016 (see EID Journal: Reassorted HPAI H5N8 Clade 2.3.4.4. - Germany 2016).
Last summer we saw scattered reports of H5N8 across much of Europe, with the UK's DEFRA Warning Of A `Constant Risk' From Avian Flu in early  September.
While far less pronounced this summer, we've been watching widespread and persistent HPAI H5N8 outbreaks in Russia and Bulgaria the past few months.

Although the finding of HPAI H5N6 in a dead Eider (even in July) is far from earth shattering, it is a reminder that - despite the inhospitable summer season - some remnants of the HPAI H5N6 virus continue to circulate in European wild birds as well.

Tuesday, July 17, 2018

Nipah Transmission In Kerala Outbreak


Credit CDC



















#13,411

The Nipah virus, first identified in 1999 after hundreds of abattoir workers in Malaysia and Singapore were infected by pigs carrying the virus (see MMWR Update: Outbreak of Nipah Virus -- Malaysia and Singapore, 1999), has been on our watch list for nearly two decades.
Carried asymptomatically by fruit bats that range across South East Asia and the Indian Ocean region - Nipah, (and its Australian cousin Hendra) - can occasionally spill over into humans, horses, pigs, and presumably other mammals. 

While outbreaks of Nipah since 1999 have been relatively small, widely scattered, and mostly reported out of Bangladesh - last May the Indian Government announced their third NiV outbreak since 2001, with the last one in 2007.
Human-to-human transmission - primarily in households and in hospital settings - has been frequently reported with the Nipah virus, but is generally described as `limited'.
Last night CIDRAP News carried a brief report (see Nipah outbreak report details hospital transmission patterns) on the apparently robust human-to-human transmission of the virus in this 19-person outbreak. 
News Scan for Jul 16, 2018

Nipah outbreak report details hospital transmission patterns

A report summing up all the investigation findings in India's Nipah virus outbreak says 17 of 19 patients appear to have contracted the virus from the index patient, a 26-year-old man, Press Trust of India (PTI) reported yesterday, citing findings released by health officials from Kerala state.

The people exposed to the first patient included 3 family members, 4 people at the first hospital that treated him, and 10 at a medical college hospital where he was taken for a computed tomography scan. One patient was infected by another patient at the first hospital.

People infected at the first hospital included the man's sister, who helped care for him. Though the man was at the second hospital for only 1 day, he passed the virus to 10 people.
(Continue . . . )

The good news in all of this is that most of the H-2-H transmission appears to be from the index patient to others, while only one secondary transmission (patient to patient) was documented.
As we've discussed previously (see Two MERS-CoV Hospital Super Spreading Studies), some patients shed more virus than others, and are therefore more able to infect others. 
Additionally, the index patient in an outbreak isn't usually identified as being highly infectious right away, so initial infection control procedures may be lax.  Once additional cases show up, they tend to be isolated more quickly, limiting their ability to further spread the virus.

The concern is, that the Nipah virus already has two of the three qualities we look for in an emerging pandemic threat.  It can jump fairly easily to humans, and it has a very high (75%) mortality rate. 
All it lacks is the ability to transmit H-2-H efficiently, and in a sustained manner.  And like MERS-CoV, and Ebola, and (to a lesser extent) Avian flu, it is part way there.
In the 2013 paper The pandemic potential of Nipah virus by Stephen P. Luby, the author writes (bolding mine):
Characteristics of Nipah virus that increase its risk of becoming a global pandemic include: humans are already susceptible; many strains are capable of limited person-to-person transmission; as an RNA virus, it has an exceptionally high rate of mutation: and that if a human-adapted strain were to infect communities in South Asia, high population densities and global interconnectedness would rapidly spread the infection.
Two weeks ago, in IJID: Enhancing Preparation For Large Nipah Outbreaks Beyond Bangladesh, we looked at a new open-access article that appeared in the International Journal of Infectious Diseases, that discussed the potential of the Nipah virus producing a large urban epidemic, similar to what we saw in West Africa with Ebola in 2014.

And the Nipah virus is on the short list of select agents considered to have significant bio-terrorism applications (see National Academy Of Sciences: Biodefense in the Age of Synthetic Biology).

While novel influenza - because of its mutability, transmissibility, and impressive track record  - remains the pandemic threat that keeps most scientists up at night, it is far from the only threat.
The next pandemic could also come from a bat coronavirus, a mutation in the Monkeypox virus, an exotic hemorrhagic fever, or from something completely out of left field. 
All reasons why pandemic preparedness needs to become a year-round national priority, not just something we think about during severe flu seasons or during the centenary of a particularly bad global epidemic.

For more on the challenges posed by the next pandemic, you may wish to revisit:

The Challenge Of Promoting Pandemic Preparedness

Pandemic Unpreparedness Revisited
Smithsonian Livestream: “The Next Pandemic: Are We Prepared?"
World Bank: World Ill-Prepared For A Pandemic