Thursday, March 28, 2024

Mexico Reports HPAI H5N2 For the 1st Time in Nearly 30 Years

Credit Wikipedia

#17,971

Long before the emergence of the Asian lineage of the HPAI H5N1 virus in Guangdong Province in the mid-1990s, both LPAI (Low path avian influenza) and HPAI (High path) H5 viruses circulated in wild birds and poultry around the globe.   
The earliest known HPAI H5 virus was A/chicken/Scotland/59 (H5N1), which killed two flocks of chickens in Scotland in 1959. China's H5N1 virus rose to fame because it was the first HPAI H5 virus known to infect and sicken humans. 
During the 1980s and 1990s, a North American lineage of LPAI and HPAI H5N2 infected poultry flocks in the United States, Mexico, and the Dominican Republic.  The USDA cites two major outbreaks:

  • The 1983-84 HPAI H5N2 outbreak resulted in humanely euthanizing approximately 17 million chickens, turkeys and guinea fowl in Pennsylvania and Virginia to contain and eradicate the disease.
  •  In 2004, USDA confirmed an HPAI H5N2 outbreak in chickens in Texas. The disease was quickly eradicated thanks to close coordination and cooperation between USDA and State, local, and industry leaders.   
Mexico dealt primarily with LPAI H5N2 until the mid-1990s, when an outbreaks of HPAI H5N2 in Puebla, Mexico prompted the government to adopt poultry vaccination. Over the past 30 years, Mexico's LPAI H5N2 has reportedly diversified into 5 distinct clades (see Evolutionary Dynamics of Mexican Lineage H5N2 Avian Influenza Viruses). 

This week, for the first time since June of 1995, Mexico is reporting HPAI H5N2 on a non-commercial poultry farm with 117 free-range birds.  The WAHIS report states:
EPIDEMIOLOGICAL COMMENTS
The presence of highly pathogenic avian influenza (HPAI) virus subtype H5N2 was confirmed through PCR tests, virus isolation, genetic sequencing and intravenous pathogenicity index (IVPI) test, in the state of Michoacán, in a backyard farm. The premises have no contact with other poultry because no commercial poultry farm is implemented in the municipality. The sanitary situation of Mexico regarding this disease remains unchanged, since HPAI subtype H5N2 is not present in birds defined as "poultry" at the moment.

SENASICA is furthering its epidemiological investigation of the event and continues to urge poultry farmers to reinforce biosecurity measures on their farms and to immediately notify any anomaly observed in their animals, in order to protect national poultry production. The active epidemiological surveillance program is being maintained in technified production units, backyards, federally inspected slaughterhouses and municipal slaughterhouses as well as the monitoring of wild birds at national level.

Mexico's SENASICA reports:


Highly pathogenic AH5N2 avian influenza registered in a backyard unit in Michoacán
This epidemiological event does not represent a risk to human health, since the virus is exclusive to birds, nor does it affect the supply of chicken and eggs for the country.

National Agri-Food Health, Safety and Quality Service | March 27, 2024 | Release

The General Directorate of Animal Health of Senasica highlighted that commercial poultry farming is not involved.


The National Agri-Food Health, Safety and Quality Service (Senasica) confirmed the presence of highly pathogenic avian influenza (HPAI) AH5N2 in a free-range family production unit in Huetamo, Michoacán.

The General Directorate of Animal Health (DGSA) of Senasica highlighted that commercial poultry farming is not involved, explaining that the virus was detected in an isolated area and there are no commercial poultry farms registered in at least 100 kilometers around, therefore that the outbreak does not compromise the animal health status of our country.

This epidemiological event does not represent a risk to human health, since the virus is exclusive to birds, nor does it affect the supply of chicken and eggs for the entire country, which is why an increase in the prices of these poultry products is not seen. .

The agency of the Ministry of Agriculture and Rural Development reported that doctors from the Directorate of the Mexico-United States Commission for the Prevention of Foot and Mouth Disease and other Exotic Animal Diseases (CPA) of the DGSA began the investigation after A veterinarian reported high mortality on a farm that raised birds for self-consumption, in which, of a total of 120 birds, 117 had died at the time of the report.

Given the discovery, the DGSA immediately ordered the backyard unit to be quarantined and the CPA doctors applied the necessary counter-epidemic measures to deactivate the outbreak, such as cleaning, disinfection and establishing a sanitary vacuum period.

The first molecular biology RT-PCR results issued by official laboratories confirmed the presence of an H5 avian influenza virus, subsequently, through specialized tests, including viral isolation, primary genomic sequencing and the intravenous pathogenicity index. , it was confirmed that it was a highly pathogenic H5N2 avian influenza virus.

Agriculture's specialists in animal health emergency care carry out the corresponding investigations in the area to determine the origin of the infection. The activities carried out in the field are perifocal tracking in the surrounding properties and promotion of notification. Additionally, monitoring of wild birds found near the affected site was implemented in order to determine the source of contagion.

At this time, the official DGSA laboratories are carrying out deep genetic sequencing studies with the purpose of determining the possible origin of the virus.

Senasica urged poultry producers throughout the country not to let their guard down and strengthen biosafety measures in their poultry production units, both family and commercial, with the purpose of mitigating the risk of infections in domestic birds.

The highly pathogenic AH5N2 virus was identified in Mexico in commercial flocks in 1994 and was eradicated in 1995. Since then, our country has remained free of this highly pathogenic agent.

Any person who produces, processes, handles, moves or markets birds must immediately report to the health authority any abnormal behavior in their flocks, unusual mortality or any other suspicion of this disease to the telephone number 800 751 2100, or from their mobile phone through of the “AVISE” app, available for Android devices.

It isn't clear whether this H5N2 virus is a reassortment of HPAI H5N1 clade 2.3.4.4b, or a new incarnation caused by the spontaneous mutation of an LPAI H5 virus into an HPAI (see graphic below).

The fact that it was detected in a small, non-commercial flock, in a relatively remote region of Mexico may help contain this incident.  But given HPAI H5's tendency to overachieve, it's worth our keeping an eye on.

Wednesday, March 27, 2024

WAHIS Report On HPAI H5N1 Virus Detected In US Cattle

Credit https://comptroller.texas.gov/ 

#17,970

Information on the HPAI H5 infections in cattle in Texas and Kansas remains scant, but late yesterday the WOAH WAHIS dashboard carried the following brief preliminary epidemiological report on the virus.

EPIDEMIOLOGICAL COMMENTS

Highly pathogenic avian influenza (HPAI) H5N1 Eurasian lineage goose/Guangdong clade 2.3.4.4b was confirmed in samples from sick cattle collected from at least one dairy farm in Kansas and at least one dairy farm in Texas.
The initial sequences represent a sporadically detected 4 gene reassortant (B3.13 per GenoFlu) descended from the previously predominant genotype B3.2 first observed in wild birds in November 2023. No markers for mammalian adaptation nor antiviral resistance were observed.
This is an evolving situation - additional work and studies are in process. Federal and state agencies are moving quickly to conduct additional testing for HPAI, as well as viral genome sequencing, so that we can better understand the situation, including characterization of the HPAI strain or strains associated with these detections.

We've discussed often that we aren't dealing with a single H5N1 threat, but rather with an array of similar H5N1 viruses that are continually reassorting and evolving.  As a segmented virus with 8 largely interchangeable parts, the flu virus is like a viral LEGO (TM) set which allows for the creation of unique variants called genotypes. 


Genotypes are created when two flu viruses inhabit the same host, allowing them to reassort into a hybrid.  Even when we limit the field to a specific subtype (like H5N1), and a specific sub-clade (like 2.3.4.4b), there can still be dozens of genotypes due to reassortment.

Although this is rapidly changing situation, last fall researchers from several U.S. labs published a `snapshot' of H5N1's diversity in the United States in the months following its arrival in December of 2021, which found that the virus rapidly reassorted with local wild bird avian influenza viruses generating six major (and numerous minor) genotypes.



 Sungsu Youk a f, Mia Kim Torchetti b, Kristina Lantz b, Julianna B. Lenoch c, Mary Lea Killian b, Christina Leyson a, Sarah N. Bevins c, Krista Dilione c, Hon S. Ip d, David E. Stallknecht e, Rebecca L. Poulson e, David L. Suarez a, David E. Swayne a, Mary J. Pantin-Jackwood a

Abstract
Highly pathogenic avian influenza viruses (HPAIVs) of the A/goose/Guangdong/1/1996 lineage H5 clade 2.3.4.4b continue to have a devastating effect on domestic and wild birds. Full genome sequence analyses using 1369 H5N1 HPAIVs detected in the United States (U.S.) in wild birds, commercial poultry, and backyard flocks from December 2021 to April 2022, showed three phylogenetically distinct H5N1 virus introductions in the U.S. by wild birds.
Unreassorted Eurasian genotypes A1 and A2 entered the Northeast Atlantic states, whereas a genetically distinct A3 genotype was detected in Alaska. The A1 genotype spread westward via wild bird migration and reassorted with North American wild bird avian influenza viruses. Reassortments of up to five internal genes generated a total of 21 distinct clusters; of these, six genotypes represented 92% of the HPAIVs examined. By phylodynamic analyses, most detections in domestic birds were shown to be point-source transmissions from wild birds, with limited farm-to-farm spread.

While some genotypes fare better than others, new reassortants tend to cluster in different geographic regions.  Some may thrive and spread widely, while others may be less biologically `fit', and are unable to compete. 


Hopefully we'll get a more detailed analysis of this virus in the days ahead, along with a better idea of its spread in cattle, goats, and potentially other livestock.

National Tsunami Awareness Week 2024

 
#17,969

Today (March 27th) is the 60th anniversary of the Great Alaskan earthquake of 1964, and that state will test its tsunami warning system (see announcement below) later today as part of National Tsunami Awareness Week.

Officials to Test Tsunami Warning System in Alaska March 27, 2024

On Wednesday, March 27th at approximately 10:20 am, the National Weather Service, Alaska Division of Homeland Security and Emergency Management, and the Alaska Broadcasters Association will conduct a test of the Alaska tsunami warning system as a part of tsunami preparedness week in Alaska. The test will be broadcast on radio and television stations and the broadcast will state that it is only a test. Some communities may activate their sirens. NOAA Weather Radio listeners will hear a tone alert followed by a test message. The test will not be sent to cellphones via the Wireless Emergency Alert (WEA) system, although in an actual Tsunami Warning this system would be used.

After the test, we invite you to provide feedback at www.ready.alaska.gov.

Once again, a tsunami warning system test will be conducted on Wednesday, March 27th at approximately 10:20 am. The test will be canceled in the event of any significant seismic activity.
Alaska's 1964 earthquake produced significant tsunami effects both locally, and thousands of miles away, killing 5 in Oregon and 13 in California. March 11th was also the 13th anniversary of Japan's 2011 Tōhoku Earthquake & Tsunami which killed in excess of 15,000 people. 

In 1960 Chile's Valdivia 9.4–9.6 earthquake sent a train of tsunamis across the Pacific, causing heavy damage and loss of life in Hawaii, Japan, and beyond (see NOAA Report).

 

Tsunamis are usually generated by large earthquakes, or underwater volcanic explosions, although massive undersea avalanches - and in rare instances - an asteroid strike can generate one.  

The west coast of North America, since it is vulnerable to tsunamis generated by seismic events in JapanAlaska, and throughout the Pacific rim - including the long expected `big one' off the Pacific Northwest's coast (see Just A Matter Of Time) - is viewed as the most `at risk' region of the continental United States and Canada.

In 2013 the USGS released a report detailing the likely West Coast impact of a tsunami generated by a 9.1 Alaskan earthquake – and the numbers are sobering.  From the USGS news release  Experts Team Up on Tsunami Resilience in California:

In this scenario approximately 750,000 people would need to be evacuated, with 90,000 of those being tourists and visitors. Additionally, one-third of the boats in California's marinas could be damaged or completely sunk, resulting in $700 million in losses. It was concluded that neither of California's nuclear power plants would likely be damaged by this particular event.

The study (link) also estimates damage to marinas, businesses and homes range between $3.5 billion and $6 billion, and as many as 8,500 could be left homeless. 

But, as we've discussed previously (see The Caribbean’s Hidden Tsunami Potential (Revisited), both the Caribbean and the Atlantic also have a history of seismic activity, making our East and Gulf Coast vulnerable to tidal waves as well.

In 1995, Montserrat's previously dormant Soufrière Hills volcano sprang to life, destroying the capital city of Plymouth, and rendering half the island uninhabitable.

In 2013 the USGS warned the Earthquake/Tsunami Hazard in Caribbean Higher Than Previously Thought, stating `Enough strain may be currently stored in an earthquake zone near the island of Guadeloupe to cause a magnitude 8 or larger earthquake and subsequent tsunami in the Caribbean’

A list of known or suspected Atlantic Tsunamis includes:
  • November 1, 1755 - Lisbon, Portugal
  • October 11, 1918 - Puerto Rico
  • November 18, 1929 - Newfoundland
  • August 4, 1946 - Dominican Republic
  • August 18, 1946 - Dominican Republic
  • November 14, 1840 - Great Swell on the Delaware River
  • November 17, 1872 - Maine
  • January 9, 1926 - Maine
  • May 19, 1964 - Northeast USA
Around 11pm on July 3rd, 1992, a `rogue wave' - described by witnesses as being between 10 and 18 feet tall - slammed onto a 27 mile stretch of Florida Beaches (including Daytona Beach) and smashed hundreds of cars and caused as many as 75 (mostly minor) injuries.

Tsunami Risk Maps 

Even if you don't live close enough to the coast to be directly affected by a Tsunami, a major natural disaster anywhere near you can impact your life as well. Supply chains may be disrupted, roads, railways, and ports may be damaged, and utilities like power and water may be out for an extended period of time.

Knowing your local threats, whether they be tsunamis, forest fires, floods, earthquakes or hurricanes . . . and then becoming prepared to deal with them, will provide you and your family the best safety insurance available.

For information on how to prepare for a tsunami, and how to react to an imminent threat, you should visit https://www.tsunamizone.org/

The U.S. National Tsunami Hazard Mitigation Program (NTHMP) has recently released their 5-year Tsunami Hazard mitigation plan in the form of a 43-page PDF, which you can download at this link. 



For help in getting better prepared for a variety of emergencies, I would invite you to visit:

FEMA http://www.fema.gov/index.shtm

READY.GOV http://www.ready.gov/

AMERICAN RED CROSS http://www.redcross.org/





ECDC/EFSA Quarterly Avian Influenza Overview Dec 2023 - Mar 2024


#17,968

While one can be comforted by the relatively low number of confirmed human avian flu infections since 2015 (see ECDC/EFSA chart above), by almost every other metric the avian flu threat appears to be increasing around the globe. 

HPAI H5Nx clade 2.3.4.4b in particular has made great strides, expanding both its geographic and host range, but it is far from alone. We are also closely monitoring several other zoonotic influenza viruses including H3N8, H5N6, LPAI H9N2, and H5N1 clade 2.3.2.1c.


The HPAI H5 threat has changed substantially over the past 8 years, starting out with a recently reassorted H5N8 in 2016, then transitioning (via reassortment) to H5N6 in 2018, and then finally back to H5N1 in 2020. With these changes in subtype came significant changes in its behavior.
While H5N1 is the dominant subtype, there dozens of genotypes circulating in Europe, with even more globally. Some of these genotypes are likely more dangerous, or better adapted to mammals, than others.
Perhaps most concerning, we've seen a record number of mammalian spillovers around the world - most recently involving farmed cattle and goats in the United States - something which has never been reported previously.  This is in addition to tens of thousands of marine and terrestrial mammals killed by the virus over the past 3 years. 
Surveillance and reporting from many regions of the world being limited, it is likely that many spillover events - and some human infections - go unreported.
Four times a year the ECDC publishes a highly detailed avian influenza surveillance report and while they tend to be EU centric, in its 69 pages you'll find substantial coverage of outbreaks and infections from around the world.  

These reports make excellent (and frequently updated) reference material, and I keep the latest version on my desktop for that very reason.  

Due to its length, I've just reproduced the executive summary and link below.  Highly recommended.

Avian influenza overview December 2023–March 2024

Surveillance and monitoring
26 Mar 2024
Time period covered: December 2023–March 2024

Between 2 December 2023 and 15 March 2024, highly pathogenic avian influenza (HPAI) A(H5) outbreaks were reported in domestic (227) and wild (414) birds across 26 countries in Europe.

Executive summary

Compared to previous years, although still widespread, the overall number of HPAI virus detections in birds was significantly lower, among other reasons, possibly due to some level of flock immunity in previously affected wild bird species, resulting in reduced contamination of the environment, and a different composition of circulating A(H5N1) genotypes.
Most HPAI outbreaks reported in poultry were primary outbreaks following the introduction of the virus by wild birds. Outside Europe, the majority of outbreaks in poultry were still clustered in North America, while the spread of A(H5) to more naïve wild bird populations on mainland Antarctica is of particular c
possibly due to some level of flock immunity in previously affected wild bird species
oncern.
For mammals, A(H5N5) was reported for the first time in Europe, while goat kids in the United States of America represented the first natural A(H5N1) infection in ruminants.
Since the last report and as of 12 March 2024, five human avian influenza A(H5N1) infections, including one death, three of which were clade 2.3.2.1c viruses, have been reported by Cambodia. China has reported two human infections, including one fatal case, with avian influenza A(H5N6), four human infections with avian influenza A(H9N2) and one fatal case with co-infection of seasonal influenza A(H3N2) and avian influenza A(H10N5). The latter case was the first documented human infection with avian influenza A(H10N5).
Human infections with avian influenza remain rare and no sustained human-to-human infection has been observed. The risk of infection with currently circulating avian H5 influenza viruses of clade 2.3.4.4b in Europe remains low for the general population in the EU/EEA. The risk of infection remains low to moderate for those occupationally or otherwise exposed to infected animals.

        Avian influenza overview December 2023–March 2024 - EN - [PDF-2.71 MB]

Tuesday, March 26, 2024

A Brief History Of Influenza A In Cattle/Ruminants

The host range for all four types (IAV, IBV, ICV, and IDV) of influenza viruses.
 

#17,967

The report yesterday that dairy cows in Texas, Kansas, (and likely) New Mexico have been infected with HPAI H5N1 - which followed the previous week's report of infected goat kids in Minnesota - is surprising, but not entirely without precedent.  

As noted previously, in 2008 researchers at Germany's FLI successfully infected four calves with an older clade of HPAI H5N1 (see EID Journal Experimental Infection of Cattle with HPAI H5N1), but reports of natural infection have been rare.

Admittedly, cattle are only rarely tested for HPAI, but a 2013 an H5N1 seroprevalence study in Egypt found that - while some horses, donkeys, and swine in the region showed evidence of past infection - cattle, sheep, goats and buffalo did not (see Sero-prevalence of Avian Influenza in Animals and Human in Egypt)

Although not influenza A - for the past dozen years we've been following research on the newly discovered Influenza D virus - which was first detected in swine, but is now believed to primarily infect cattle (see Viruses: Influenza D in Domestic and Wild Animals).

While we haven't seen any evidence that Influenza D can cause symptomatic illness in humans, in the summer of 2016 - in Serological Evidence Of Influenza D Among Persons With & Without Cattle Exposure - researchers reported finding a high prevalence of antibodies against Influenza D among people with cattle exposure. They wrote:
IDV poses a zoonotic risk to cattle-exposed workers, based on detection of high seroprevalence (94–97%). Whereas it is still unknown whether IDV causes disease in humans, our studies indicate that the virus may be an emerging pathogen among cattle-workers. 

Relatively little has appeared recently in the literature regarding influenza A infection in cattle and/or ruminants, but in 2019 the Journal Viruses carried a detailed review of the literature going back decades.  

While some of these reports are spotty, they cite a number of papers on both influenza and  influenza-like illnesses in cattle and goats. In some cases, viruses were identified, while in other cases they were not. 

This is a lengthy and detailed review, and I've only reproduced some excerpts below, so you'll want to  follow the link to read the report in its entirety.  I'll have a postscript after the break.

Viruses. 2019 Jun; 11(6): 561.
Published online 2019 Jun 17. doi: 10.3390/v11060561
PMCID: PMC6631717
PMID: 31213032

Influenza A in Bovine Species: A Narrative Literature Review

Chithra C. Sreenivasan,1 Milton Thomas,2 Radhey S. Kaushik,1 Dan Wang,1,3 and Feng Li1,3,*

Abstract

It is quite intriguing that bovines were largely unaffected by influenza A, even though most of the domesticated and wild animals/birds at the human–animal interface succumbed to infection over the past few decades. Influenza A occurs on a very infrequent basis in bovine species and hence bovines were not considered to be susceptible hosts for influenza until the emergence of influenza D. 

This review describes a multifaceted chronological review of literature on influenza in cattle which comprises mainly of the natural infections/outbreaks, experimental studies, and pathological and seroepidemiological aspects of influenza A that have occurred in the past.
The review also sheds light on the bovine models used in vitro and in vivo for influenza-related studies over recent years. Despite a few natural cases in the mid-twentieth century and seroprevalence of human, swine, and avian influenza viruses in bovines, the evolution and host adaptation of influenza A virus (IAV) in this species suffered a serious hindrance until the novel influenza D virus (IDV) emerged recently in cattle across the world.

Supposedly, certain bovine host factors, particularly some serum components and secretory proteins, were reported to have anti-influenza properties, which could be an attributing factor for the resilient nature of bovines to IAV. Further studies are needed to identify the host-specific factors contributing to the differential pathogenetic mechanisms and disease progression of IAV in bovines compared to other susceptible mammalian hosts.
(Excerpts)


 
5. Natural Cases of Influenza A in Bovines

First recorded evidence of influenza in cattle occurred in 1949, where 160,000 cattle were infected in the western and middle part of Japan [76]. This incidence of cattle influenza ran for a short course with recovery in 2–3 days and the documented symptoms included high temperature (40–42 °C), blepharitis, nasal discharge, anorexia, tympanites, pneumonia, joint problems, and a decrease in lactation. 

This report also mentioned about some major cattle influenza outbreaks occurred previously in the Fall of 1889 and 1893, and some minor outbreaks in 1914–1916 in Japan [76]. The same study also mentioned an experimental infection of 11 calves, using nasal discharge/defibrinated blood from diseased animals and the successful virus isolation in mice, characterized by few deaths and lung and liver lesions at the 20th serial passage.

The first report on influenza virus isolation from animals was documented by Romvary et al. [88] from Hungary in 1962, which described the isolation of IAV strains similar to human H2 HA glycoprotein from pigs and sheep during 1959–1960. Romvary et al. [46] also isolated porcine IAV strains bearing human H3 HA glycoprotein.
Lopez and Woods reviewed influenza viruses from cattle and the first cattle-origin influenza isolate was reported by Barb et al., 1962, cited in [47]. Furthermore, there were reports on cattle influenza from several countries primarily from the old Union of Soviet Socialist Republics (USSR), and the publications were mostly in the Russian language, with the rare occurrence of English abstract and keywords.

Among these, the earliest report was on the seroepidemiological study of influenza in domestic species of animals in 1969 [25]. During the period 1970–80, cattle isolates of influenza A have been reported from different parts of the world, post/around the time 1968 Hong Kong H3N2 pandemic occurred in humans.


In 1973, the isolation and identification of the A/Hong Kong/1/1968 (H3N2) virus from cattle suffering respiratory diseases were reported in Russia [45]. The earliest cattle influenza A strain studied under experimental conditions was A/calf/Duschambe/55/71 (H3N2) from Russia. This strain was derived from a natural case of respiratory illness in a terminally ailing calf and was isolated in embryonated chicken eggs [45].

Both H1N1 and H3N2 strains were isolated from cattle later. Few of these isolated strains reported include Sw/Shope (H1N1) from Hungary and several H3N2 strains from the USSR. The two viruses isolated from Hungary and the USSR possessed type 2 neuraminidase; however, HA glycoproteins were unidentified [47]. The H3N2 strains were similar to the prototypic human H3N2 strain A/Hong Kong/1/1968 (Schild G, C., World Influenza Center, London).

(SNIP)

In 1997, an idiopathic condition manifested in dairy cows in Bristol, southwest England with a sporadic drop in milk production [95]. Brown et al. [96,97] also reported seroconversion against influenza A in cattle from Great Britain, which was markedly associated with reduced milk yield and respiratory disease. However, the virus isolation from these seroconverted animals was unsuccessful. Interestingly, these cattle seroconverted to influenza A virus alone, with no detectable antibodies against BVD, IBR, PI3, and BRSV, suggestive of the etiological role of influenza A in the reduction of milk yield.

Furthermore, in 1999, Gunning et al. [98] also reported that the natural cases of influenza in milking cows increased with an annual incidence rate of 10–20% in some herds of England with a sudden drop in milk yield, mild pyrexia, anorexia, occasional respiratory signs such as nasal discharge and increased respiratory rate. High levels of neutrophils and haptoglobin were present in the blood in most of these cases. Serological screening of paired sera collected from five cattle herds with the same clinical history against IBR, PI3, BRSV, adenovirus, M. bovis, H. somnus, C. psittaci, C. brunetti, P. hemolytica, P. trehalosi, treponemes revealed antibodies against BRSV and PI3 in all herds, while BVD and IBR were detected only in some herds. On the other hand, these cattle sera demonstrated significantly high antibody titer to two human IAVs: 60% for A/England/333/80 (H1N1) and 65% for A/England/427/88 (H3N2) and only 5% of the cows were seronegative against both viruses [98].

These observations clearly indicated the exposure and natural susceptibility of cattle to human influenza A viruses. 
Concurrently, Dr Ian Brown and his colleagues at Veterinary Laboratories Agency near Weybridge, United Kingdom reported the presence of influenza genes in cattle around the late 1990s (https://www.nature.com/news/1998/020107/full/news020107-4.html. accessed January 21, 2019). However, no related peer-reviewed records were available.

In Northern Ireland, a seroepidemiological study conducted on 84 paired acute and convalescent cattle sera collected from 17 outbreaks, against A/England/333/80 (HIN1) and A/England/427/88 (H3N2) during 1998–1999, with clinical manifestations of respiratory disease, diarrhea, and milk drop syndrome demonstrated seroconversion in 56.5 and 58.8% of the convalescent sera against H1N1 and H3N2 respectively. While H3N2 antibody titers were higher compared to H1N1 in general, this study also revealed a higher rate of seropositivity against human H3N2 over porcine H3N2 strains. However, virus isolation in specific pathogen-free chicken embryos was unsuccessful from 142 cattle with similar clinical manifestations [99].

The association of human influenza A viruses with milk drop in cows was prevalent in the early 2000s. In 2008, Crawshaw et al. [100] demonstrated rising antibody titers against same human influenza viruses, A/England/333/80 (H1N1) and A/England/427/88 (H3N2) from a Holstein Friesian herd suffering from acute fall in milk production and tested seronegative against BRSV, BVD, IBR, and PI3 viruses.

          (SNIP)

11. Summary

Here, we conducted a comprehensive review of the literature available on the past influenza cases/studies occurring globally in ruminant (bovine, caprine, ovine) population, and have summarized the overall influenza A prevalence in bovines. In this review, we have discussed the host range of the four types of influenza, emphasizing the susceptibility/utility of bovine in vivo and in vitro models to influenza A studies over recent years.
Even though natural cases of influenza occurred in bovines causing influenza-like respiratory disease with bronchopneumonia, epizootic cough, nasal discharge, lacrimation, or other extrapulmonary signs such as milk drop, only a few cases culminated in successful virus isolation.
Cattle-origin IAV strains were isolated during the early 1970s, around the time when Hongkong/1968 human IAV strains (H3N2) were prevalent. Although the relatedness of HA glycoprotein of these cattle IAV strains to human H2 and H3 prototypes was reported, sufficient data/characterization studies were lacking to support the extent of genetic relatedness.
Pigs, which were domesticated by humans 1500 years after cattle, are naturally susceptible to all four influenza types and are excellent mixing vessels of influenza. Hence, the refractory nature of bovines against influenza A could be due to species-specific host-associated interference as discussed before. Compared to IAV and IBV (eight segmented genomes), bovines are naturally susceptible to IDV, and lately to ICV (seven segmented genomes) as indicated by the seroprevalence studies and isolation of complete viral genomes, thus contributing significantly to the bovine respiratory disease along with other bacterial/viral pathogens.
The transboundary occurrence of influenza D in bovines, compounded with its extraordinary thermal and pH stability [236] compared to other influenza types, demands further studies to study the pathobiological aspects of this virus and its predisposition in bovine species. The fact that bovines harbor some natural predisposing factors, amenable for the tissue tropism and pathogenesis of ICV and IDV, while detrimental to IAV and IBV, would make them a suitable model to delineate influenza type-specific host–pathogen interactions, and further studies are needed to address this differential disease pathogenesis at the cellular and molecular level.

          (Continue . . . )

 

Exactly why HPAI H5N1 is suddenly turning up in ruminants after 20 years is unknown. Some of it may be due to testing bias; since cattle have long been assumed to be poor hosts for influenza A, they are less likely to be tested, which only helps perpetuate the belief. 

But we've also seen a dramatic shift in HPAI H5N1's ability to infect mammals around the globe over the past 2 or 3 years.  It does appear to be expanding its host range.  A genomic analysis of the viruses isolated from these ruminants will hopefully yield some valuable clues.

An obvious concern now is, if H5N1 has adapted well enough to spillover into cattle and goats, are swine next?  A year ago, the ECDC/EFSA Avian Influenza Overview December 2022 – March 2023 warned:

The additional reports of transmission events to and potentially between mammals, e.g. mink, sea lion, seals, foxes and other carnivores as well as seroepidemiological evidence of transmission to wild boar and domestic pigs, associated with evolutionary processes including mammalian adaptation are of concern and need to be closely followed up.

While we've seen scattered reports of H5N1 in pigs (see here , here, and here), the virus has yet to gain a foothold (see EID Journal: Low Susceptibility of Pigs against Experimental Infection with HPAI Virus H5N1 Clade 2.3.4.4b).

In swine, HPAI would potentially have access to a plethora of other influenza A viruses, which could greatly increase the risk of viral reassortment. 

This is obviously a developing story, with investigations underway in several states.  Right now, we have more questions than answers.

Stay tuned.  

Monday, March 25, 2024

USDA Statement on HPAI In Dairy Cattle in Texas & Kansas Herds


#17,966


This afternoon the USDA announced test findings on the illness in dairy cows I reported on over the weekend (see Curious Reports of Unknown Disease In Dairy Cows (Texas, Kansas & New Mexico) - and just as we saw with goat kids in Minnesota last week - it turns out to be due to HPAI (presumably H5N1). 

The USDA's announcement follows, after which I'll have a bit more.

Federal and State Veterinary, Public Health Agencies Share Update on HPAI Detection in Kansas, Texas Dairy Herds
Published: Mar 25, 2024
 
Wild migratory birds believed to be source of infection; viral testing and epidemiologic efforts continue

Commercial milk supply remains safe due to both federal animal health requirements and pasteurization



Contact: APHISpress@usda.gov

WASHINGTON, March 25, 2024 – The U.S. Department of Agriculture (USDA), Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC), as well as state veterinary and public health officials, are investigating an illness among primarily older dairy cows in Texas, Kansas, and New Mexico that is causing decreased lactation, low appetite, and other symptoms.

As of Monday, March 25, unpasteurized, clinical samples of milk from sick cattle collected from two dairy farms in Kansas and one in Texas, as well as an oropharyngeal swab from another dairy in Texas, have tested positive for highly pathogenic avian influenza (HPAI). Additional testing was initiated on Friday, March 22, and over the weekend because farms have also reported finding deceased wild birds on their properties. Based on findings from Texas, the detections appear to have been introduced by wild birds. Initial testing by the National Veterinary Services Laboratories has not found changes to the virus that would make it more transmissible to humans, which would indicate that the current risk to the public remains low.

Federal and state agencies are moving quickly to conduct additional testing for HPAI, as well as viral genome sequencing, so that we can better understand the situation, including characterization of the HPAI strain or strains associated with these detections.

At this stage, there is no concern about the safety of the commercial milk supply or that this circumstance poses a risk to consumer health. Dairies are required to send only milk from healthy animals into processing for human consumption; milk from impacted animals is being diverted or destroyed so that it does not enter the food supply. In addition, pasteurization has continually proven to inactivate bacteria and viruses, like influenza, in milk. Pasteurization is required for any milk entering interstate commerce.

Federal agencies are also working with state and industry partners to encourage farmers and veterinarians to report cattle illnesses quickly so that we can monitor potential additional cases and minimize the impact to farmers, consumers and other animals. For the dairies whose herds are exhibiting symptoms, on average about ten percent of each affected herd appears to be impacted, with little to no associated mortality reported among the animals. Milk loss resulting from symptomatic cattle to date is too limited to have a major impact on supply and there should be no impact on the price of milk or other dairy products.


This is a rapidly evolving situation, and USDA andCredit U.S. Fish & Wildlife 
 federal and state partners will continue to share additional updates as soon as information becomes available. More information on biosecurity measures can be found here.

 

Although cattle have previously been successfully infected in the laboratory with older clades of HPAI H5 (see EID Journal Experimental Infection of Cattle with HPAI H5N1), this is the first confirmation of natural HPAI infection in cattle in the United States.

The fact that we're seeing both cattle and goats - across several Midwestern states - suddenly infected with HPAI is a concern, and likely speaks to the amount of virus being carried by migratory birds which are heading north on their spring migration. 

Credit U.S. Fish & Wildlife 


Since cattle and goats - which have never been infected outside of the lab - are suddenly falling victim to the virus, farms with more far susceptible animals (like swine or mink) may be at a greater risk as well.  Some recent warnings include:

EID Journal: Divergent Pathogenesis and Transmission of Highly Pathogenic Avian Influenza A(H5N1) in Swine

Netherlands: Zoonoses Experts Council (DB-Z) Risk Assessment & Warning of Swine As `Mixing Vessels' For Avian Flu

PNAS: Mink Farming Poses Risks for Future Viral Pandemics

Another reminder that avian flu continues to surprise, and that we underestimate it at our own peril.