MMWR: Mild H7N3 Infections In Two Poultry Workers - Jalisco, Mexico

 

Photo Credit SENASICA

 

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Roughly 10 weeks ago (June 27th) we learned of an outbreak of Highly Pathogenic H7N3 avian influenza among poultry in Jalisco, Mexico; the first such outbreak in that country since an outbreak of H5N2 in the early 1990s.

 

Since that time, more than 22 million birds have either died from the disease, or have been culled, and Mexico’s poultry industry has taken a terrible beating.

 

The good news - according to a report yesterday in MeatPoultry.com - is no new infections have been reported in the past 3 weeks, and restocking of birds is set to begin (see Mexico tallies birds culled, restocking to begin).

 

While there are a number of avian flu viruses circulating in the wild, the OIE only requires that H5s and H7s be reported due to their known ability to mutate from a low pathogenic virus to highly pathogenic virus.

 

Among the avian influenzas, H5N1 virus gets the bulk of the headlines, and rightfully so. While a matter of some controversy (see Revisiting The H5N1 CFR Debate), among known human cases, the mortality rate has been a staggering 60%.

 

Other strains that have demonstrated at least some ability to infect humans include H7, H9, H10, and H11. Fortunately, most of the time these rare infections have produced only mild flu symptoms (sometimes only conjunctivitis).

 

For now, these viruses are primarily a threat to the poultry industry, and to a lesser extent, people working in direct contact with infected fowl.

 

Although global surveillance and reporting on novel avian viruses in humans is spotty at best, some known H7 cases include:

Chart lifted and edited from CIDRAP’s excellent overview Avian Influenza (Bird Flu): Implications for Human Disease  showing known H7 avian flu infections in humans over the two decades.

 

 

To this short list of human cases we can now add two more (admittedly, very mild) cases, as is detailed in today’s MMWR.

 

 

Notes from the Field: Highly Pathogenic Avian Influenza A (H7N3) Virus Infection in Two Poultry Workers — Jalisco, Mexico, July 2012

Weekly

September 14, 2012 / 61(36);726-727

During June–August 2012, Mexico's National Service for Health, Safety, and Food Quality reported outbreaks of highly pathogenic avian influenza (HPAI) A (H7N3) virus in poultry on farms throughout the state of Jalisco (1,2). This report describes two cases of conjunctivitis without fever or respiratory symptoms caused by HPAI A (H7N3) virus infection in humans associated with exposure to infected poultry.

 

Patient 1. On July 7, a poultry worker aged 32 years complaining of pruritus in her left eye was examined at a clinic in Jalisco. Physical findings included redness, swelling, and tearing. Conjunctivitis was diagnosed; the patient was treated symptomatically and recovered fully. Because the patient had collected eggs in a farm where HPAI A (H7N3) virus was detected, the Institute for Epidemiological Diagnosis and Reference, Mexico, tested ocular swabs from both of her eyes for influenza A (H7) by real-time reverse transcription–polymerase chain reaction (rRT-PCR), and embryonated chicken eggs were inoculated for viral isolation. The swab material was positive for influenza A (H7) virus by rRT-PCR and virus was isolated from each eye. These findings were reported to the World Health Organization on July 19, and full genome sequences (CY125725–32) were uploaded to GenBank. The virus was closely related by nucleotide sequence to previously reported HPAI A (H7N3) viruses collected during poultry outbreaks in Jalisco with sequences available in GenBank (JX397993, JX317626).

 

Patient 2. A man aged 52 years, who was a relative of patient 1 and worked on the same farm, developed symptoms consistent with conjunctivitis on July 10 and sought care at a local clinic on July 13. He was treated symptomatically and recovered without sequelae. When public health authorities became aware of this patient, they obtained eye swabs, which were tested by rRT-PCR, revealing influenza A (H7).

 

Mexico has continued its efforts to contain poultry outbreaks in affected areas in Jalisco. Those efforts include quarantining affected farms, culling infected birds, vaccinating uninfected birds, and disinfecting contaminated areas. Government agencies also have provided personal protective equipment to farm personnel and are conducting active surveillance for influenza-like illness (ILI) and severe acute respiratory illness at two sentinel sites near the outbreak.

 

Avian influenza A viruses are designated as HPAI or low pathogenicity avian influenza (LPAI) based on molecular characteristics of the virus and the ability of the virus to cause disease and mortality in birds (3). To date, only influenza A (H5) and (H7) subtypes have been described as HPAI. Influenza A (H7) subtype viruses have been detected in wild birds in many parts of the world and can cause outbreaks in poultry. Influenza A (H7) infection in humans is uncommon, but can occur after direct contact with infected birds, especially during outbreaks of influenza A (H7) virus among poultry (4). Illness can include conjunctivitis without fever, upper respiratory tract symptoms, or both (4,5), and severity can range from mild to fatal (4). In the United States, avian influenza outbreaks in poultry are rare, but they are detected and reported sporadically. In the United States, only two cases of illness with LPAI A (H7) virus infection are known to have occurred in humans, both of whom recovered (6,7).

 

The conjunctivitis cases in Jalisco most likely represent HPAI A (H7N3) virus transmission from infected poultry to humans through direct contact. United States agricultural, public health, and clinical personnel should be aware of these poultry outbreaks with transmission to humans in a neighboring country. Persons working with poultry known or suspected to be infected with influenza A viruses should use appropriate personal protective equipment, including face masks, gloves and eye protection (e.g., goggles). Clinicians and epidemiologists should consider avian influenza A virus infection in patients who have conjunctivitis or ILI and have contact with poultry in areas with known avian influenza outbreaks. Clinicians who suspect avian influenza A virus infections in humans should obtain a conjunctival or respiratory specimen, or both, depending on signs and symptoms, and submit samples to a national, regional, or state public health laboratory to enable specific influenza testing. Clinicians also should consider early empiric antiviral treatment of suspected cases with a neuraminidase inhibitor (8,9). Public health officials should survey family members and contacts of infected persons to find cases of human-to-human transmission.

 

 

Since the H7 viruses usually only produce mild symptoms in humans, you may be wondering why all the concern over a couple of H7 infections?

 

The answer is simple.  H7s, like all influenza viruses, are constantly mutating and evolving.

 

What is mild, or relatively benign today, may not always remain so.

 

And in 2008 we saw a study in  PNAS that suggested the H7 virus might just be inching its way towards better adaptation to humans.

 

So we watch, with considerable interest, anytime a novel flu virus manages to jump to humans.  Even if only in a very limited fashion.

 

For more details on that study, and some more posts on the H7 constellation of flu viruses, you may wish to revisit:

 

H7's Coming Out Party

H7 Study Available Online At PNAS

 

When Flu Strains Collide

»» Read More

Updating Mexico’s H7N3 Outbreak

 

Photo Credit SENASICA

 

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Just over three weeks ago the OIE was notified by Mexico’s Director General of Animal Health Dr Hugo Sanchez Fragoso of an outbreak of highly pathogenic H7N3 avian influenza among poultry in the state of Jalisco (see Mexico: High Path H7 In Jalisco). 

 

A week later, Mexico’s Agricultural Ministry (Secretaría de Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación; SAGARPA) Declared a National H7N3 Animal Health Emergency as the H7N3 virus continued to spread.

 

Map Credit OIE

 

 

Since humans have only rarely been reported to have been infected by this strain of avian flu, the big concern right now is for poultry operations. Cesar de Anda, vice chairman of the International Egg Commission, was quoted by EFE news yesterday as stating:

 

"The industry will fail to produce $50 million, not only from the cost of the (dead) birds, but also from the intrinsic value of production, the generation of wealth and of indirect jobs in other fields."

 

According to Anda, if this outbreak is not brought under control, as many as 32,000 jobs could be at risk.

 

To date, 2.5 million poultry have either died, or been destroyed because of this virus, and according to a press release from SENASICA (Mexico’s Food Safety agency) as many as 17 million birds in the region may be at risk.

 

The latest OIE Filing (Follow-up report No. 3 ) states the source or origin of the virus remains unknown, and provides brief summaries of 31 separate outbreaks. 

 

Under Epidemiological comments, they list:

 

• During the epidemiological surveillance carried out in response to the event, the National Food Quality, Food Safety and Health Service (SENASICA) has taken samples in the outbreaks and around the outbreaks in 148 poultry farms.
• 31 farms were identified by viral isolation, diagnosis is ongoing in other 83 and 34 have tested negative to H7N3 highly pathogenic virus.
• The population at risk in these 148 farms amounts to about 17 million birds, of which 86.1% of layers, 6.9% of broilers and 7% of breeders.
• As part of the measures taken to reduce the risk, the buffer zone has been extended to 60 km around the index outbreak and includes 161 poultry farms at risk with a population of 25.8 million of birds.
• Control measures on birds and their products movements have been strengthened in the quarantine area and eight check points have been established with the support of 26 health technicians with 9 vehicles that monitor the quarantine zone.
• Epidemiological surveillance activities continue in the outbreaks, around the outbreaks and in the buffer zone. As a measure to reduce the risk, sampling will be carried out in neighbouring States and in poultry farms at risk outside the buffer zone.

 

In the first six months of 2012, 14 countries have reported outbreaks of high path avian flu with strains ranging from H5N1 and H5N2 to H7N3. Surveillance and reporting around the world is spotty at best, and so it is likely that we don’t hear about all of the outbreaks.

 

For now, however, these viruses are primarily a threat to the poultry industry, and to a far lesser extent, people working in direct contact with infected fowl.  While H7 viruses have been known to infect humans on rare occasions, most of the reported cases have produced only mild to moderate illness.

 

• In 2003 an outbreak of H7N7 at a poultry farm in the Netherlands went on to infect at least 89 people. Most of the victims were only mildly affected, but one person died.
• In 2004 two people in British Columbia tested positive for H7N3 (see Health Canada Report) during an outbreak that resulted in the culling of 19 million birds.
• In 2006 and 2007 there were a small number of human infections in Great Britain caused by H7N3 (n=1)  and H7N2 (n=4), again producing mild symptoms.

 

For now, H7 avian influenzas are presumed to pose a low public health threat.  But H7s, like all influenza viruses, are constantly mutating and evolving.

 

In 2008 we saw a study in  PNAS that suggested the H7 virus might just be inching towards adapting to humans. For more details on that study, you may wish to revisit H7's Coming Out Party and H7 Study Available Online At PNAS.

 

So, while the H7 virus poses a minimal risk to human health at this time, it pays to keep an eye on outbreaks such as the one in Jalisco.

 

Influenza viruses are constantly changing, and evolving, always seeking an evolutionary advantage. So, what was true about a specific flu virus yesterday, may not hold true tomorrow.

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Mexico Declares National H7N3 Animal Health Emergency

 

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Mexico’s Agricultural Ministry (Secretaría de Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación; SAGARPA) today announced a national animal health emergency as the H7N3 outbreak that made headlines last week (see Mexico: High Path H7 In Jalisco) has reportedly now affected more than 1.7 million birds.

 

ChannelNewsAsia has an AFP report Mexico declares bird flu emergency, but a short version of the announcement can be found on the SENASICA (National Health Service, Food Safety and Food Quality) website:

 

Avian Influenza

Avian Influenza type A, subtype H7N3 does not affect humans, only birds, according to Organization Animal Health (OIE).

See Frequently Asked Questions
Audio News

Press release

Was published today in the Official Journal of the Federation agreement that activates, integrates and operates the National Emergency Animal Health, pursuant to Article 78 of the Federal Animal Health Law, to diagnose, prevent , control and eradicate avian influenza virus type A, subtype H7N3, actions taken since last week in coordination with the farming.

 

While H7N3 is not considered to represent a high human health risk, the statement that it does not affect humans is not strictly true. As I wrote last week, there have been a handful of (generally mild) human infections detected with this subtype of avian flu.

 

The following is a machine translation of a more detailed press release (including information on the quarantine, slaughter, vaccination, and the destruction of infected poultry), which is available from the SARGAPA website. 

 

SENASICA published in the Official Gazette of the National Emergency Animal Health

Mexico City, July 2, 2012

Was published today in the Official Journal of the Federation agreement that activates, integrates and operates the National Emergency Animal Health, pursuant to Article 78 of the Federal Animal Health Law, to diagnose, prevent, control and eradicate avian influenza virus type A, subtype H7N3, actions taken since last week in coordination with the farming.

The agreement is issued under the June 20, 2012 the National Health Service, Food Safety and Food Quality (SENASICA) confirmed the presence of a virus highly pathogenic avian influenza exotic for Mexico in two municipalities of Jalisco and considers that requires immediate attention for its control and eventual eradication, to prevent severe damage to the poultry industry.

The coordination of the National Emergency Animal Health will be in charge of SENASICA through the Directorate General of Animal Health (DGSA), which will be supported by the Mexico - United States for the Prevention of FMD and other diseases Exotic Animals (CPA).

 

Although the virus is focused on municipalities and Acatic Tepatitlan, Jalisco, the operation will be activated throughout the country, in order to prevent the spread of the disease, for which the country is divided into eight regions emergency .

 

The eight regions will be regulated and directed by SENASICA through the DGSA, with the support of the CPA and actions will be executed in each region under the supervision of the Coordinators responsible for compliance to the Agreement will have the Groups State Animal Health Emergency (GEESA), led by the coordinators of the CPA.

 

The agreement also establishes the animal health measures and coordinated urgent application to the diagnosis, prevention, control and eradication of Avian Influenza virus type A subtype among which are: animal health education on avian influenza to poultry and people and legal entities related to the poultry industry.

 

Under the transmission of the virus highly pathogenic avian influenza in birds occurs by direct or indirect animal products and byproducts from infected birds exposed and sets the control of the movement of poultry and their products and products as well as other animal species regulated by the Animal Health Act and provisions thereunder, which may represent a risk to poultry.

 

They also provide animal health and ordering cords retention and disposition of poultry products and byproducts, as well as biological, chemical, pharmaceutical and food for use or consumption by these birds that could cause an outbreak of Avian Influenza.

 

As animal health measures include diagnostic work and identification of avian influenza virus, quarantine and isolation for affected farms and the work you reinforce surveillance and epidemiological research.

 

To avoid transmission of avian influenza virus type A subtype H7N3 is ordered sanitation practices, disinfection, disinfestation, sterilization, using germicides and pesticides in animals, premises and transport.

 

SENASICA further instructs the culling sick or exposed to avian influenza and disposal of poultry products and byproducts in the manner specified in the body.

 

Similarly, immunization will be permitted upon express authorization of SENASICA, to protect and prevent the spread of the disease.

 

SENASICA establish mechanisms of coordination with other agencies of the Federal Government, the Governments of the States, the National Technical Advisory Council for Animal Health, the National Union of Poultry Farmers, as well as poultry producers and individuals linked to activities related to poultry, which are required to provide the SENASICA all the support and technical and administrative cooperation, as well as the epidemiological data and production is required to diagnose, prevent, control and eradicate avian influenza virus type A subtype H7N3 of the country.

 

Finally, the agreement indicates that the Ministry of Agriculture, Livestock, Rural Development, Fisheries and Food, through the National Health Service, Food Safety and Food Quality, assess the health status of the areas recognized as being of low prevalence, in control, and eradication or free of notifiable avian influence, in order to determine the measures necessary for the proper implementation of the Agreement.

 

 

And the actual declaration may be found HERE.

 

While public health authorities will no doubt be keeping their eyes on this situation, this is primarily a concern to agricultural interests. 

 

An H7N3 outbreak in 2004, highly pathogenic H7N3 outbreaks in British Columbia's Fraser Valley back in 2004 led to the culling of 19 million birds.

»» Read More

Mexico: High Path H7 In Jalisco

Photo Credit – FAO

 

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Last night Lisa Schnirring writing for CIDRAP NEWS  brought us details on the first highly pathogenic bird flu outbreak in Mexico in nearly two decades.  The last time was during the mid-1990s, and the virus was H5N2.

 

This time, the culprit it is H7N3.

 

Follow the link below to read  Lisa’s excellent report, after which I’ll return with a bit more.

 

Tests reveal high-path H7N3 in Mexican poultry farm outbreaks

Lisa Schnirring Staff Writer

Jun 26, 2012 (CIDRAP News) – Mexican veterinary authorities are intensifying avian influenza control efforts in a region that houses several large commercial farms after further tests determined that the strain responsible for more than 200,000 bird deaths at three farms is the highly pathogenic H7N3 subtype.

(Continue . . . )

 

While there are a number of avian flu viruses circulating in the wild, the OIE only requires that H5s and H7s be reported due to their known ability to mutate from a low pathogenic virus to highly pathogenic virus.

 

When it comes to avian influenzas, the H5N1 virus gets the bulk of the headlines, and rightfully so. While a matter of some controversy (see Revisiting The H5N1 CFR Debate), among known human cases, the mortality rate has been a staggering 60%.

 

Other strains that have demonstrated at least some ability to infect humans include H7, H9, H10, and H11. Fortunately, most of the time these rare infections have produced only mild flu symptoms (sometimes only localized conjunctivitis).

 

Last April, in EID Journal: Human Infection With H10N7 Avian Influenza we looked at some recent H10 infections, and in 2011 we explored A Little Background On H11 Avian Influenzas.

 

For now, however, these viruses are primarily a threat to the poultry industry, and to a lesser extent, people working in direct contact with infected fowl.

 

Although global surveillance and reporting on novel avian viruses in humans is spotty at best, some known H7 cases include:

 

• In 2003 an outbreak of H7N7 at a poultry farm in the Netherlands went on to infect at least 89 people. Most of the victims were only mildly affected, but one person died.
• In 2004 two people in British Columbia tested positive for H7N3 (see Health Canada Report) during an outbreak that resulted in the culling of 19 million birds.
• In 2006 and 2007 there were a small number of human infections in Great Britain caused by H7N3 (n=1)  and H7N2 (n=4), again producing mild symptoms.

 

For now, H7 avian influenzas are presumed to pose a low public health threat, which may leave you wondering why all this fuss over this outbreak of H7N3?

 

The H7s, like all influenza viruses, are constantly mutating and evolving.  

 

While considered mild today, there are no guarantees that the virus won’t pick up virulence over time, or reassort with another virus and increase its affinity for humans.

 

Four years ago, we saw a study in PNAS that indicated that the H7 virus might just be moving more towards adapting to humans.

 

Contemporary North American influenza H7 viruses possess human receptor specificity: Implications for virus transmissibility

You can read more about this in a couple of blogs from 2008, H7's Coming Out Party and H7 Study Available Online At PNAS.

 

The last pandemic, you will recall,  came out of left field; from a region of the world (North America), host species (swine), and influenza strain (H1N1) all considered unlikely to spark a global epidemic.

 

Which is why we pay attention whenever there is an outbreak of a novel flu virus for which mankind may have little or no immunity.

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