CDC FluView Week 21: 1 Novel (H1N1v) Flu Infection - Michigan

Swine Variant Human Cases : 2010-2018  - Credit CDC

 
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Although last winter's seasonal flu has all but disappeared in the U.S., each summer we keep an eye out for sporadic cases of swine-variant influenza, which are often associated with exposure to pigs at county fairs.

Over the past 15 years we've seen more than 460 confirmed human infections (see chart above), although this likely significantly under-represents the true number of cases.

While most of these reported infections have been mild-to-moderate in severity, some people have required hospitalization, and deaths - while rare - have occurred (see J. Virology: Analysis Of A Swine Variant H1N1 Virus Associated With A Fatal Outcome).

The CDC describes Swine Variant viruses in their Key Facts FAQ.

What is a variant influenza virus?

When an influenza virus that normally circulates in swine (but not people) is detected in a person, it is called a “variant influenza virus.” For example, if a swine origin influenza A H3N2 virus is detected in a person, that virus will be called an “H3N2 variant” virus or “H3N2v” virus.

The CDC's general risk assessment of these swine variant (H1N1v, H1N2v, H3N2v) viruses reads:

CDC Assessment

Sporadic infections and even localized outbreaks among people with variant influenza viruses may occur. All influenza viruses have the capacity to change and it’s possible that variant viruses may change such that they infect people easily and spread easily from person-to-person. The Centers for Disease Control and Prevention (CDC) continues to monitor closely for variant influenza virus infections and will report cases of H3N2v and other variant influenza viruses weekly in FluView and on the case count tables on this website

The CDC issued updated clinical Guidance for Human Infections with Swine Flu Viruses earlier this month, and in April we looked at how the CDC investigates cases (see The CDC & Novel Flu Investigations).

Today's abbreviated (summer) FluView report contains details of 2019's first reported swine variant flu infection, which occurred in elderly resident in Michigan; one without an obvious exposure to swine.

Novel Influenza A Virus:

One human infection with a novel influenza A virus was reported by Michigan. This person was infected with an influenza A(H1N1) variant (A(H1N1)v) virus.

The patient is an adult > 65 years of age, was hospitalized, and completely recovered from their illness. While no exposure to swine has been reported, an investigation is ongoing into the source of the patient’s infection. This is the first A(H1N1)v virus infection detected in the United States in 2019.

Influenza viruses that circulate in swine are called swine influenza viruses when isolated from swine, but are called variant viruses when isolated from humans. Seasonal influenza viruses that circulate worldwide in the human population have important antigenic and genetic differences from influenza viruses that circulate in swine.

Early identification and investigation of human infections with novel influenza A viruses are critical so that the risk of infection can be more fully understood and appropriate public health measures can be taken. Additional information on influenza in swine, variant influenza infection in humans, and strategies to interact safely with swine can be found at http://www.cdc.gov/flu/swineflu/index.htm.

Additional information regarding human infections with novel influenza A viruses can be found at http://gis.cdc.gov/grasp/fluview/Novel_Influenza.html.

Last summer the CDC - in conjunction with the USDA and 4H - released an ambitious 60-page graphic novel on swine variant flu and how disease detectives investigate outbreaks.

The Junior Disease Detectives: Operation Outbreak Graphic Novel

While avian flu appears - at least temporarily - to be on the decline globally, swine variant influenza remains an ongoing threat, both in the United States and around the world.

A few recent blogs on swine variant flu include:

Trop. Med & Inf. Dis.: Mammalian Pathogenicity and Transmissibility of H1 Swine Variant Influenza

BMC Vet.: Novel Reassortant H1N2 & H3N2 Swine Influenza A Viruses - Chile

J. Virology: Pathogenesis & Transmission of H3N2v Viruses Isolated in the United States, 2011-2016

JVI: Divergent Human Origin influenza Viruses Detected In Australian Swine Populations

The `Other' Novel Flu Threat We'll Be Watching This Summer

Emerg. Infect. & Microbes: Novel Triple-Reassortant influenza Viruses In Pigs, Guangxi, China

China MOA Reports Two More (Small) African Swine Fever Outbreaks

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Relaying the official reports from China's MOA on their African Swine Fever crisis feels - admittedly - like I'm compounding a felony, as these reports almost certainly only tell us a small fraction of the story.

Whether this is by design - as has been charged by some - or due to local reluctance to report `bad news' up the chain of command to Beijing, is impossible to say.  But I'd wager it is a bit of both.

We've seen persistent rumors (Google search `死猪') and media reports (see Reuters report Piles of pigs: Swine fever outbreaks go unreported in rural China) - along with repeated discoveries of ASF-Positive Pig Carcasses floating off the Chinese Mainland coast - that suggest the situation there is much worse than reported.

Although the videos turning up on YouTube are often impossible to verify, many of them are difficult to dispute.  Dead pigs floating in lakes, rivers, and streams. Dumped by roadsides, etc.

A particularly horrific one was highlighted yesterday by an ABC (Australian Broadcasting Company) report, which appears to show thousands of pigs being buried alive (see China struggles to contain African swine fever, resorts to mass live-pig burials, millions of culls).

The latest FAO ASF Report - dated May 30th - has China reporting:

Since the China Ministry of Agriculture and Rural Affairs (MARA) confirmed its first African swine fever (ASF) outbreak in Liaoning Province on 3 August 2018, 136 ASF outbreaks detected in 32 Provinces/Autonomous Regions/Municipalities/Special Administrative Region. 1,129,000 pigs have been culled in an effort to halt further spread.

But other industry estimates put China's losses more than 100 times greater.  A Rabobank Research report released in April estimated that between 150-200 million Chinese pigs had already been lost to ASF, and that China's pig production would drop 30% in 2019.

Other estimates (see ASF China: Global agribusiness suffers; estimates vary) propose even greater losses, perhaps exceeding 50%.

All of which makes these once or twice weekly MOA reports of a few dozen pigs lost to the virus a bit hard to take seriously.   

African swine fever epidemic in Menghai County, Yunnan Province

Date: 2019-05-29 18:54 Author: Source: Ministry of Agriculture and Rural Press Office 

The Information Office of the Ministry of Agriculture and Rural Affairs was released on May 29, and an African swine fever epidemic occurred in Menghai County, Xishuangbanna, Yunnan Province.

On May 29, the Ministry of Agriculture and Rural Affairs received a report from the China Animal Disease Prevention and Control Center, which was diagnosed by the Yunnan Provincial Center for Animal Disease Control and Prevention. The pigs raised in the villages of Gelang and the townships in Menghai County, Xishuangbanna, suffered from African swine fever. Up to now, the relevant farmers have stored 80 pigs, 37 diseases and 12 deaths.

Immediately after the outbreak, the Ministry of Agriculture and Rural Affairs dispatched a steering group to guide local disposal work. The local government has started the emergency response mechanism as required, and adopted measures such as blockade, culling, harmless treatment, disinfection, etc., to treat all dead pigs and culled pigs harmlessly. At the same time, all pigs and their products are prohibited from being transferred out of the blockade, and pigs are prohibited from being transported into the blockade. At present, the above measures have been implemented.

Duyun City, Guizhou Province, illegally transported into pigs in the provinces of the province to detect African swine fever
 
Date: 2019-05-31 17:56 Author: Source: Ministry of Agriculture and Rural Press Office 

The Information Office of the Ministry of Agriculture and Rural Affairs was released on May 31, and the city of Duyun, Qiannan Prefecture, Guizhou Province, illegally transported into the pigs in the province to detect the African swine fever.

On May 31, the Ministry of Agriculture and Rural Affairs received a report from the China Animal Disease Prevention and Control Center. In the southern part of the country, the South China Sea intercepted an illegal traffic-clearing vehicle 10 kilometers away from the Duyun South exit. 

There were 32 pigs on the car. 1 head, 1 death. It was diagnosed by the Guizhou Provincial Animal Disease Prevention and Control Center and the African swine fever was detected from the pigs contained in the vehicle. According to preliminary investigations, the batch of pigs were purchased by the shippers from other provinces and illegally transported into Guizhou.

After the outbreak, the Ministry of Agriculture and Rural Affairs immediately directed local investigations on epidemic situation supervision and epidemiological investigation. The local government has started the emergency response mechanism according to the requirements, culling and harmless treatment of the pigs in the same vehicle, comprehensively cleaning and disinfecting the vehicles, and comprehensively inspecting and disinfecting the road sections involved. At present, the above measures have been implemented, and the local public security department has already controlled the personnel involved.

Meanwhile, the FAO is reporting the following summaries from China's neighbors.

Democratic People’s Republic of Korea
The Ministry of Agriculture, Anti-Epizootic Department confirmed its first ASF outbreak in Chagang-Do occurred on 23 May 2019. 77 of 99 pigs in the Buksang cooperative farm, Ri, Usi County, became sick and died from the disease [refrence].

Mongolia

Since its first report on 15 January 2019, 11 outbreaks in 6 provinces and in Ulaanbaatar have been reported, involving 105 farms/households. More than 3,115 pigs, more than 10 percent of the total pig population in Mongolia, have died/been destroyed due to the ASF outbreaks.

Viet Nam
Since the Ministry of Agriculture and Rural Development (MARD) confirmed its ASF outbreaks on 19 February 2019, a total of 45 provinces/cities reported outbreaks, more than 1,700,000 pigs have been culled.

Cambodia
Since the Ministry of Agriculture Forestry and Fisheries confirmed its first ASF outbreak in Som Kaninh village, Som Thom commune, O Ya Dav District, Ratanakiri Province on 2 April 2019, more than 2400 pigs have died or been culled.

WHO Novel Flu Summary & Risk Assessment - May 2019

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Before H7N9 emerged in China in 2013, avian H5N1 was the king of the novel flu contenders, going back to early in the last decade (see chart above).  In late 2014 and the first half of 2015 - after several years of slow decline - it staged a major comeback in Egypt (see EID Journal: H5N1 In Egypt)..

Since then, however, H5N1 has reportedly only infected a handful of humans.

I say reportedly because there remain many areas in the world where the virus circulates, but influenza testing and sub-typing is rarely - if ever - performed (see 2013's Nepal: Human H5N1 Testing (Or Lack Thereof).

After a year-long drought in cases, in early May we learned of a fatal H5N1 infection in Nepal (see WHO SEARO Statement On Nepal H5N1 Case), which occurred in March. 

The World Health Organization has published their latest Summary and Risk assessment on novel influenza, which provides details on the recently reported H5N1 case in Nepal and Oman's first reported human infection with H9N2.

Influenza at the human-animal interface

Summary and assessment, 10 April to 10 May 2019

New infections 1 : Since the previous update on 9 April 2019, new human infections with avian influenza A(H5N1) and A(H9N2) viruses were reported.

Risk assessment: The overall public health risk from currently known influenza viruses at the human-animal interface has not changed, and the likelihood of sustained human-to-human transmission of these viruses remains low. Further human infections with viruses of animal origin are expected.

IHR compliance: All human infections caused by a new influenza subtype are required to be reported under the International Health Regulations (IHR, 2005). 2 This includes any influenza A virus that has demonstrated the capacity to infect a human and its haemagglutinin gene (or protein) is not a mutated form of those, i.e. A(H1) or A(H3), circulating widely in the human population. Information from these notifications is critical to inform risk assessments for influenza at the human-animal interface.

Avian Influenza Viruses

Current situation:

Avian influenza A(H5) viruses

Since the last update on 9 April 2019, one new laboratory-confirmed human case of influenza A(H5N1) virus infection was reported to WHO from Nepal on 30 April 2019.

The patient was a 19 -year-old male resident of Kathmandu who had illness onset on 17 March 2019. He was hospitalized on 23 March. A throat swab sample was collected for laboratory testing. Antiviral treatment was initiated on 25 March. The patient passed away on 29 March.

The detection of influenza A(H5N1) in the sample from the case was confirmed at the WHO Collaborating Centre (CC) in Tokyo, Japan (National Institute of Infectious Diseases). Further characterization of the virus is underway.

Among other response actions, a detailed epidemiological investigation was completed. The investigation indicated that the most likely source of exposure of the case to the virus occurred at a live bird market. No symptomatic contacts of the case were detected. Multiple detections of influenza A(H5N1) in domestic birds in Nepal since February 2019 have been reported to the World Organisation for Animal Health (OIE). 

Since 2003, a total of 861 laboratory-confirmed cases of human infection with avian influenza A(H5N1) virus, including 455 deaths, have been reported to WHO from 17 countries (see Figure 1). This is the first human case of A(H5N1) virus infection reported from Nepal.

Risk Assessment: 
1. What is the likelihood that additional human cases of infection with avian influenza A(H5) viruses will occur?

The overall risk assessment is unchanged. Most human cases were exposed to A(H5) viruses through contact with infected poultry or contaminated environments, including live poultry markets. Since the viruses continue to be detected in animals and environments, further human cases can be expected.

2. What is the likelihood of human-to-human transmission of avian influenza A(H5) viruses?

Even though small clusters of A(H5) virus infections have been reported previously including those involving healthcare workers, current epidemiological and virological evidence suggests that influenza A(H5) viruses have not acquired the ability of sustained transmission among humans, thus the likelihood is low.

3. What is the risk of international spread of avian influenza A(H5) viruses by travellers?

Should infected individuals from affected areas travel internationally, their infection may be detected in another country during travel or after arrival. If this were to occur, further community level spread is considered unlikely as evidence suggests these viruses have not acquired the ability to transmit easily among humans. 

       Avian influenza A(H9N2) viruses

Since the last update on 9 April 2019, one new laboratory-confirmed human case of influenza A(H9N2) virus infection was reported to WHO from Oman on 24 April 2019.

A 13-month-old female from living in Oman developed illness on 17 March 2019 and was hospitalized on 22 March. Following treatment, the case recovered and was discharged on 1 April.

The detection of influenza A(H9N2) virus in a nasopharyngeal sample from the case was confirmed at the WHO CC in the USA (Centers for Disease Control and Prevention). Further characterization of the virus is underway. The case may have had indirect exposure to chickens. No further human cases were reported among the close contacts. Avian influenza A(H9N2) viruses are enzootic in poultry in Asia.

This is the first confirmed human case of infection with an avian influenza virus reported from Oman.

        (Continue . . . .)

 
Despite relatively few documented human infections (see FluTrackers List) - and having a reputation for causing generally less severe human illness than its avian H5 & H7 cousins - LPAI H9N2 is still considered an important player in the avian flu world.

• H9N2 has become widespread - even ubiquitous - among poultry across Europe and the Middle East
• Serological studies suggest human infection is far more common than standard surveillance would have us believe (see J. Infect & Public Health: High Seroprevalence Of Avian Influenza H9 Among Poultry Professionals In Pakistan)
• H9N2 reassorts easily with other viruses, and its internal genes are often found inside many HPAI viruses (including H5N1, H5N6, and H7N9) -  (see The Lancet's Poultry carrying H9N2 act as incubators for novel human avian influenza viruses) 
• H9N2 viruses continue to accrue evolutionary changes, which include mammalian adaptations, and increased binding to human receptor cells (see PLoS Path: Genetics, Receptor Binding, and Transmissibility Of Avian H9N2).

So, while H9N2 may not be at the top of our pandemic threats list, it is regarded as having at least some pandemic potential (see CDC IRAT SCORE), and several candidate vaccines have been developed over the years.

OIE Notification: African Swine Fever In North Korea

Credit OIE

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For a couple of days there have been rumors of African Swine Fever being detected in North Korea (see Korean Times S. Korea prepares for possible outbreak of swine fever in North), but until this morning we had no official confirmation.

The OIE has published an immediate notification (h/t Pathfinder at FluTrackers) regarding the detection of ASF at a cooperative farm in Chagang-do, very near their border with Liaoning, China.

Given the secrecy that shrouds North Korea, it is a little surprising to see an official notification.  There have been rumors and speculation for some months, but this is the first official acknowledgement.

IJID: Making The Case For Designating Measles Resurgence A PHEIC

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Three weeks ago, in WHO Update & Risk Assessment: Measles In Europe, the World Health Organization reported a major increase in measles during the first quarter of 2019. Last February, in Philippines DOH Declares & Then Expands Measles Outbreak Declaration, after an almost 10-fold increase in cases during the first 19 days of 2019 over the previous year.

Ten days ago, the CDC held a COCA Call: Most Measles Cases In 25 Years, which asked the question `Is This the End of Measles Elimination in the United States?'

According to the WHO, `Even though a safe and cost-effective vaccine is available, in 2017, there were 110 000 measles deaths globally, mostly among children under the age of five.'

A number which seems destined to rise significantly in 2019.

The June edition of the International Journal of Infectious Diseases contains an editorial assessment (see below) making the case for declaring this global resurgence a `PHEIC', a Public Health Emergency of International Concern. 

This is a relatively lengthy and detailed report, and so I've only posted the opening salvos of their argument and their conclusions. Follow the link to read the open-access article in its entirety.

I'll have a postscript when you return.

Is the global measles resurgence a “public health emergency of international concern”?

David N. Durrheim, Natasha S. Crowcroftb, Lucille H. Blumbergc

Corresponding Editor: Eskild Petersen, Aarhus, Denmark

DOI: https://doi.org/10.1016/j.ijid.2019.04.016

Highlights

• Public Health Emergencies of International Concern require coordinated international responses.
• There has been a recent alarming global increase in measles deaths and unprecedented rapid international spread.
• Measles is re-established in the Americas, and in certain Western Pacific and European countries.
• Mobilisation of extraordinary resources by the international community is urgently required.

The 2005 revision of the International Health Regulations (IHR) came into force on 15 June 2007 and is legally binding on 196 countries, including all the Member States of World Health Organization (WHO). In the IHR, a public health emergency of international concern (PHEIC) is defined as: “an extraordinary event that may constitute a public health risk to other countries through international spread of disease and may require an international coordinated response.” (World Health Organization, 2005). The IHR requires that countries notify the WHO of any public health event that meets any two of the following four criteria: Is the public health impact of this event potentially serious?; Is this event unusual or unexpected?; Is there the potential for international spread?; or Is there the potential for travel and trade restrictions?

The purpose of declaring a PHEIC is to focus attention on those acute public health risks that have the potential to cross borders and threaten people worldwide, and “require coordinated mobilisation of extraordinary resources by the international community” for prevention and response. The decision to declare a PHEIC rests with the WHO Director-General.

To date four PHEICs have been declared; the: 2009 H1N1 influenza pandemic declaration; 2014 polio declaration; 2014 Ebola declaration with the outbreak in West Africa; and 2016 Zika virus declaration. The polio PHEIC declaration stands apart as poliovirus is certainly not a novel or emerging pathogen, but it sets an interesting and laudable precedent. The PHEIC issued on 5 May 2014 references the resurgence of polio after its near-eradication, deeming this an “extraordinary event and a public health risk to other States for which a coordinated international response is essential” (World Health Organization, 2014). This is the only PHEIC that remains in effect, five years after it was first declared.

        (BIG SNIP)

Should “extraordinary resources” be mobilised by the international community to respond to this public health risk that has the potential to cross borders and threaten people worldwide? If we follow the advice that Plato put in the mouth of Socrates, “we must go wherever the wind of the argument carries us.” (Plato, 1974) Thus the answer must be “yes” – measles is a de facto PHEIC – it should be declared!.

        (Continue . . . )


The bar for declaring a PHEIC is purposefully set pretty high, which was illustrated last October when the WHO IHR Committee Determined The DRC Ebola Outbreak Was Not A PHEIC. 

Despite offering some compelling arguments, I suspect selling the idea of designating Measles as a PHEIC to the IHR committee is likely to prove difficult, considering that the IHR committee reiterated their decision not to do so for the rapidly growing Ebola outbreak in the DRC last April.

Whether they would find it worthy or not, convening a meeting of the IHR Committee to discuss the situation would bring a lot of international attention to the severity of the global measles problem, and perhaps spur more action.

And that would be a small step in the right direction.

 

Denmark Reports Novel H1N2 Flu Infection

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Today, for the third time in just over a year we've a report of a novel H1N2 infection - a reassortment of A/H1N1 and A/H3N2 - from a patient residing in a northern European (see 2019 Swedish report and 2018 Netherlands case) country.

Influenza reassortment - also known as Antigenic Shift - can occur when a host (human, avian, porcine, etc.) is co-infected with two flu viruses, and they swap gene segments. Reassortment is the primary force behind the creation of novel or pandemic flu viruses (see NIAID Video: How Influenza Pandemics Occur).

Luckily, a reassortment of seasonal H1N1 and H3N2 is far less of a concern than a hybrid of seasonal flu and a novel flu virus. Last February the CDC issued the following risk assessment:

Risk Assessment:

This A(H1N2) reassortant virus is thought to pose a health risk similar to other seasonal influenza viruses. The virus has not been detected beyond this one person and current seasonal influenza vaccines would likely offer protection against this virus. Additionally, this virus does not have markers associated with resistance to the neuraminidase inhibitor class of antiviral drugs and, thus, should be susceptible to treatment with the currently recommended drugs oseltamivir, zanamivir and peramivir.

Several weeks later, in Eurosurveillance: Novel influenza A(H1N2) Seasonal Reassortant - Sweden, January 2019, we saw the following assessment.

In conclusion, our results support the observation that the currently co-circulating viruses of A(H1N1)pdm09 and seasonal A(H3N2) viruses have the potential to reassort and form new strains that can spread globally causing epidemics. Reassortment between seasonal and zoonotic influenza might lead to novel pandemic strains and therefore molecular surveillance of circulating influenza strains is of high importance.

While human H1N2 infection has only rarely been reported in recent years, we've seen sporadic outbreaks in the past.  These larger outbreaks were reassortments of the old H1N1 virus, not the 2009 H1N1 virus.

In 1988-1989 in China (see Human influenza A (H1N2) viruses isolated from China), and again between 2000 and 2003 in the Northern Hemisphere, we saw the brief appearance of a human H1N2 virus - a reassortment between the old (pre-2009) seasonal H1N1 and H3N2.

While a minor player in most regions, H1N2 was the predominant Influenza A(H1) virus reported during the UK's 2001–02 influenza season (cite).

These were human-origin H1N2 viruses, not to be confused with the swine-origin H1N2v (variant) viruses that have circulated in pigs for decades and that last year was responsible for 14 of the 17 swine variant infections reported to the CDC.

Today's translated report, which was published yesterday on mesvaccins.net,  comes from information provided by the EU's EWRS: Early Warning and Response System.

A case of influenza due to an unusual virus A (H1N2) in a patient in Denmark 

Published May 29 2019 at 12:01

Author: Claude Hengy

The Danish health authorities have notified May 26, 2019 via EWRS , a case of human influenza A (H1N2) reassortant.

The sample was collected April 11, 2019 in the Danish capital and sent to the Statens Serum Institut institution (SSI) as a sample without special notification of routine surveillance.

The sample was taken in a woman aged 74, not vaccinated against influenza, which had traveled by plane to Croatia before crossing the country, and Bosnia and Herzegovina and Montenegro, between 29 March and 5 April 2019. the patient developed symptoms of respiratory tract infection after returning April 7 and was hospitalized on 11 April. She left the hospital on 13 April.

It is not known if the patient was infected during her trip to Croatia, Bosnia and Herzegovina, Montenegro or during the trip back to Denmark. No other contact or subjects tourists present on the bus in Croatia has developed symptoms.

The levy nasopharyngeal helped highlight an influenza virus A. The whole genome sequencing showed a hemagglutinin gene from the A (H1N1) and a gene pdm09 neuraminidase from the A (H3N2), of the 2018/2019 seasonal influenza. No mixed infection A (H1N1) pdm09 and A (H3N2) has been demonstrated. The virus was named A / Denmark / 3176/2019 (see here more information about the influenza vaccine nomenclature ).

The Statens Serum Institute estimates that the subsequent risk of transmission of this virus is weak.

(Continue . . . )

Sources: European Center for Disease Prevention and Control; World Health Organization ; Flu News Europe website.

While the current paucity of case detections suggests these hybrid H1N2 viruses don't transmit very well, it is worth noting this patient doesn't appear to have been co-infected with H1N1 and H3N2 at the time the samples were taken.

These H1N2 cases are worth our notice, but a far greater concern would be seeing a humanized (seasonal H1N1 or H3N2) influenza virus reassort with a novel flu - like H7N9 or H5N1 - potentially producing a highly virulent and easily transmitted hybrid (see EID Journal: Human Co-Infection with Avian and Seasonal Influenza Viruses, China).

I would imagine we'll see more updates and analysis from the CDC and the ECDC on this latest case in the days to come.

WHO Global Influenza Update #342

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While flu circulates - albeit at low levels - year-round in the tropics, generally by early May the Northern Hemisphere's flu season has well ended and the Southern Hemisphere is still a month or two away from starting.

This year has been a bit different, with an unusually protracted flu season in the United States, and an equally surprisingly high level of Flu in Australia (see chart below) over their summer months.

Influenza In South Australia: Credit Govt South Australia

Yesterday the World Health Organization published their latest global influenza report - current through May 12th - which found an increasingly quiet Northern Hemisphere, but continues to report early flu activity in many of the temperate zones south of the equator.

H3N2 is the dominant flu subtype reported in Australia, New Zealand, and South Africa, while in South America H1N1 has been most frequently reported.

The subtype that dominates can determine the severity of the flu season.

• First, because the flu vaccine for the southern hemisphere - selected last September - is expected to be more effective against H1N1 than against H3N2.
• And secondly, because H3N2 often produces a more severe flu season, and is known to hit the elderly more harshly than H1N1.

Predicting what seasonal flu will do is pretty much a mug's game, so we'll simply have to watch to see how things unfold.  Excepts from the latest WHO Flu report follow:

Influenza update - 342

27 May 2019 - Update number 342, based on data up to 12 May 2019

Information in this report is categorized by influenza transmission zones, which are geographical groups of countries, areas or territories with similar influenza transmission patterns. For more information on influenza transmission zones, see the link below:

• Influenza Transmission Zones
  pdf, 659kb

 Summary

In the temperate zones of the southern hemisphere, influenza detections increased overall.

• In Australia and New Zealand influenza detections were predominantly influenza A(H3N2) and influenza B viruses.
• In South Africa, predominantly influenza A(H3N2) viruses were detected.
• In South America, influenza A(H1N1)pdm09 viruses predominated.
• In Southern Asia, influenza activity was low overall.
• In the Caribbean, Central American countries, and the tropical countries of South America, influenza and RSV activity were low in general.
• In Eastern, West and Middle Africa, influenza activity was low across reporting countries.
• In the temperate zone of the northern hemisphere influenza activity decreased overall.
• In North America and Europe, influenza activity was low overall.
• In North Africa, influenza detections were low across reporting countries.
• In Western Asia, influenza activity was low overall, but with continued detections in a few countries on the Arabian Peninsula.
• In East Asia, decreased but continued influenza activity was reported.
  

National Influenza Centres (NICs) and other national influenza laboratories from 111 countries, areas or territories reported data to FluNet for the time period from 29 April 2019 to 12 May 2019 (data as of 2019-05-24 03:41:52 UTC). The WHO GISRS laboratories tested more than 80173 specimens during that time period. 7693 were positive for influenza viruses, of which 4383 (57%) were typed as influenza A and 3310 (43%) as influenza B.

Of the sub-typed influenza A viruses, 707 (30.9%) were influenza A(H1N1)pdm09 and 1578 (69.1%) were influenza A(H3N2). Of the characterized B viruses, 63 (2.9%) belonged to the B-Yamagata lineage and 2075 (97.1%) to the B-Victoria lineage. 

Detailed influenza update

Download PDF 

(SNIP)

Countries in the temperate zone of the southern hemisphere

Increased influenza detections were reported from countries in the temperate zone of the southern hemisphere.

• In Oceania, Australia, ILI activity and influenza detections were higher compared to the same period in previous years.Increased detections of mainly influenza A(H3N2) viruses were reported. NewCaledonia reported detections of predominantly influenza A(H1N1)pdm09 viruses. New Zealand reported increased detections of influenza A(H3N2) and influenza B Victoria lineage viruses.In New Zealand, ILI activity increased but remained below baseline. Influenza-associated hospitalizations also increased.
• South Africa reported increased influenza detections with predominantly influenza A(H3N2) and increased ILI activity. The season started in week 18 when influenza detections increased above the seasonal threshold.
• In South America, influenza detections increased above baseline and ILI activity increased in Chile, with influenza A(H1N1)pdm09 predominant among influenza detections. In Paraguay, influenza detections, of predominantly influenza A(H1N1)pdm09, and ILI increased slightly but remained around the baseline while RSV detections increased. Influenza detections were low in Argentina, Brazil and Uruguay.

Saudi MOH Announces 2 More MERS Cases

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Over the last four epidemiological weeks (#18, #19, #20 & #21) the Saudi MOH has reported an average of only 2 MERS infections per week, a far cry from the double-digit weekly tallies from earlier this spring.

Epi week #22 has started off strong, however, with 6 new cases reported over the past 3 days (see Sunday & Monday reports). 

Today the MOH reports the 5th and 6th cases of epi week #22, which includes the 7th case reported from Riyadh during the month of May.

• A 64 y.o. male from Riyadh, listed as `primary with camel contact'
• A 26 y.o. male from Buraidah, listed as `primary' with unknown camel contact

Unlike three of the last four cases reported this week, both of these patients are apparently still living.

With the Holy month of Ramadan coming to an end next week, hundreds of thousands of religious pilgrims will returning to their home countries over the coming days.

While exported cases of MERS remain remarkably few in number, public health agencies around the world will be on heightened alert for any signs of illness among returnees from the Middle East.

Emerg. Microbes & Inf.: Bactrian Camels Shed Large Quantities of MERS-CoV After Experimental Infection

Bactrian Camel – Credit Wikipedia



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Whenever a new infectious disease threat emerges - particularly those with zoonotic potential - one of the first things we look for is the host range of the pathogen.  Whether it is avian flu, Ebola, or a vector-borne disease like Zika, it is vital to understand its host range, diversity, and ecology.

Generally speaking, the greater the host range, the greater the risk to public health.

Roughly a year after the first human infection with MERS-CoV was identified in Saudi Arabia, dromedary camels were identified as major host species for the MERS coronavirus (see 2013's The Lancet Camels Found With Antibodies To MERS-CoV-Like Virus).

Bats are still believed to be the primary host reservoir for MERS, SARS, and an array of other novel pathogens (see Curr. Opinion Virology: Viruses In Bats & Potential Spillover To Animals And Humans), but the hunt continues for other susceptible species where these viruses may reside.

Complicating this search, the MERS virus doesn't appear to leave long lasting fingerprints - in the form of detectable antibodies - once the host clears the infection (see EID Journal: Antibody Response & Disease Severity In HCW MERS Survivors).

Similar waning antibody detection has been reported in camels, which means seroprevalence studies may not provide an accurate picture of how many people - or other species - have been infected with this coronavirus in the past.

In an attempt to get past this testing barrier, we've seen a number of studies that have tried to experimentally infect various species in order to identify other potential hosts.

In 2016, in Study: Experimental Infection Of Goats, Sheep & Horses With MERS-CoV, we looked at a study that reassuringly found that:

Minimal or no virus shedding was detected in all of the animals. During the four weeks following inoculation, neutralizing antibodies were detected in the young goats, but not in sheep or horses.

Four months later, in December of 2016, in EID Journal: Livestock Susceptibility to Infection with MERS-CoV, researchers experimentally inoculated llamas, pigs, sheep, and horses with the MERS virus, and found that pigs & llamas both shed the virus from the nose, and seroconverted.

Given the susceptibility of pigs to other coronaviruses (see mBio: PEDV - Porcine Epidemic Diarrhea Virus - An Emerging Coronavirus and Swine Enteric Coronavirus Diseases), this understandably raised concerns.

A 2017 study (see EID Journal: Domestic Pig Unlikely Reservoir for MERS-CoV) confirmed that while pigs can be experimentally infected with the MERS virus, they did not develop clinical disease and only shed small quantities of the virus, making them unlikely to spread the disease.

Although Bactrian camels, which are commonly found in Mongolia, Central Asia, Pakistan, and Iran belong to the same family as Dromedaries (Camelidae), a 2015 Research letter in the EID Journal found an Absence of MERS-Coronavirus in Bactrian Camels, Southern Mongolia, November 2014.

As Dromedaries and Bactrian camels share some limited geographic regions, the potential of MERS-CoV spreading to Bactrian camels - and thereby extending its threat to other human populations - is obviously a concern.

All of which brings us to a new study, published last week in Emerging Microbes & Infections, where researchers from NIAID and the Department of Biomedical Sciences at Colorado State University, inoculated two Bactrian camels and monitored them for nasal shedding and seroconversion.

This is an open access article, and I've only posted a few excerpts. Follow the link to either read (or listen to), the full article.

Listen

Original Articles
Bactrian camels shed large quantities of Middle East respiratory syndrome coronavirus (MERS-CoV) after experimental infection

Danielle R. Adney, Michael Letko, Izabela K. Ragan, Dana Scott, Neeltje van Doremalen, Richard A. Bowen & Vincent J. Munster

https://doi.org/10.1080/22221751.2019.1618687
 
Pages 717-723 | Received 05 Apr 2019, Accepted 09 May 2019, Published online: 23 May 2019

ABSTRACT

In 2012, Middle East respiratory syndrome coronavirus (MERS-CoV) emerged. To date, more than 2300 cases have been reported, with an approximate case fatality rate of 35%. Epidemiological investigations identified dromedary camels as the source of MERS-CoV zoonotic transmission and evidence of MERS-CoV circulation has been observed throughout the original range of distribution.

Other new-world camelids, alpacas and llamas, are also susceptible to MERS-CoV infection. Currently, it is unknown whether Bactrian camels are susceptible to infection. The distribution of Bactrian camels overlaps partly with that of the dromedary camel in west and central Asia.

The receptor for MERS-CoV, DPP4, of the Bactrian camel was 98.3% identical to the dromedary camel DPP4, and 100% identical for the 14 residues which interact with the MERS-CoV spike receptor. Upon intranasal inoculation with 107 plaque-forming units of MERS-CoV, animals developed a transient, primarily upper respiratory tract infection.

Clinical signs of the MERS-CoV infection were benign, but shedding of large quantities of MERS-CoV from the URT was observed. These data are similar to infections reported with dromedary camel infections and indicate that Bactrians are susceptible to MERS-CoV and given their overlapping range are at risk of introduction and establishment of MERS-CoV within the Bactrian camel populations.

        (SNIP)     

Discussion
Despite the current lack of field evidence of MERS-CoV infection in Bactrian camels, this study demonstrates that Bactrian camels can be readily infected and shed large quantities of virus in nasal secretions. If MERS-CoV were to be introduced into populations of Bactrian camels, we would expect that a potential endemic and sustained pattern of infection may result and they could act as a reservoir, similar to dromedaries, potentially exposing associated human communities to infection.

        (Continue . . . )

Saudi MOH: 2 MERS Cases (1 Secondary, 1 Deceased)

#14,093


Yesterday, in Saudi MOH: 3 MERS Cases (2 Deceased), we saw Epi Week #22 begin with two cases, both deceased, with one from Riyadh and the other from Medina.

Whenever we see cases initially announced as deceased, it raises the question as to exactly when they were diagnosed and isolated, as this increases the risks of both household, and nosocomial transmission (see J. Inf. Pub. Health: Diagnostic Delays in MERS Coronavirus Patients & Health Systems).

We've looked at some of the challenges in diagnosing MERS coronavirus infection before, including atypical presentations, intermittent-positive test results, potential transmission from asymptomatic cases, and an unreliable algorithm used by the Saudis for screening patients.


Because of the difficulties in identifying cases, the WHO continues to advise:

It is not always possible to identify patients with MERS-CoV early because like other respiratory infections, the early symptoms of MERS-CoV are non-specific. Therefore, healthcare workers should always apply standard precautions consistently with all patients, regardless of their diagnosis.

Droplet precautions should be added to the standard precautions when providing care to patients with symptoms of acute respiratory infection; contact precautions and eye protection should be added when caring for probable or confirmed cases of MERS-CoV infection; airborne precautions should be applied when performing aerosol generating procedures.

Today's MOH report contains two more cases; a secondary case (23,F) in Riyadh, who may be linked to any one of several recent cases in the Capital, and for the third time in 2 days, another deceased case (35, M), this time from Najran.

While MERS-CoV hasn't taken off the way that SARS-CoV did 16 years ago, we've seen studies (see A Pandemic Risk Assessment Of MERS-CoV In Saudi Arabia) suggesting the virus doesn't have all that far to evolve before it could pose a genuine global threat.

A little over year ago in the  WHO List Of Blueprint Priority Diseases, we saw MERS-CoV listed among the 8 disease threats in need of urgent accelerated research and development. 

Among the tools needed are faster, and more accurate diagnostic tests, and an effective armamentarium of drugs and/or vaccines. Unless and until they become available, MERS is likely to continue to spark household and nosocomial outbreaks and remain a serious public health concern.