H7N7
Encyclopedia
H7N7 is a subtype of Influenzavirus A
, a genus of Orthomyxovirus, the viruses responsible for influenza
. Highly pathogenic strains (HPAI) and low pathogenic strains (LPAI) exist. H7N7 can infect human
s, bird
s, pig
s, seals
, and horse
s in the wild; and has infected mice
in laboratory studies. This unusual zoonotic potential represents a pandemic
threat.
In 2003 in the Netherlands
89 people were confirmed to have the H7N7 influenza
virus infection following an outbreak in poultry
on several farm
s. One death was recorded. Antibodies were found in over half of 500 people tested according to the final official report by the Dutch government:
In August 2006, low pathogenic (LP) H7N7 was found during routine testing at a poultry farm in Voorthuizen
in the central Netherlands. As a precautionary measure, 25,000 chickens were culled from Voorthuizen and surrounding farms.
In June 2008, high pathogenic (HP) H7N7 was confirmed on a 25,000-bird laying unit at Shenington
, England
; probably derived from a pre-existing low pathogenic variety. "Increased mortality (2.5 per cent in one shed) and a drop in egg production had been recorded two weeks before birds started dying in large numbers on June 2, leading to the diagnosis of HP H7N7 on June 4."
In October 2009, high pathogenic (HP) H7N7 was confirmed on a farm in Almoguera
, Guadalajara
, Spain
. Hong Kong announced that it would suspend the import of poultry from Spain.
Influenzavirus A
Influenza A virus causes influenza in birds and some mammals and is the only species of Influenzavirus A. Influenzavirus A is a genus of the Orthomyxoviridae family of viruses. Strains of all subtypes of influenza A virus have been isolated from wild birds, although disease is uncommon...
, a genus of Orthomyxovirus, the viruses responsible for influenza
Influenza
Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae , that affects birds and mammals...
. Highly pathogenic strains (HPAI) and low pathogenic strains (LPAI) exist. H7N7 can infect human
Human
Humans are the only living species in the Homo genus...
s, bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s, pig
Pig
A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...
s, seals
Pinniped
Pinnipeds or fin-footed mammals are a widely distributed and diverse group of semiaquatic marine mammals comprising the families Odobenidae , Otariidae , and Phocidae .-Overview: Pinnipeds are typically sleek-bodied and barrel-shaped...
, and horse
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
s in the wild; and has infected mice
Mouse
A mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. In some places, certain kinds of field mice are also common. This rodent is eaten by large birds such as hawks and eagles...
in laboratory studies. This unusual zoonotic potential represents a pandemic
Pandemic
A pandemic is an epidemic of infectious disease that is spreading through human populations across a large region; for instance multiple continents, or even worldwide. A widespread endemic disease that is stable in terms of how many people are getting sick from it is not a pandemic...
threat.
In 2003 in the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
89 people were confirmed to have the H7N7 influenza
Influenza
Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae , that affects birds and mammals...
virus infection following an outbreak in poultry
Poultry
Poultry are domesticated birds kept by humans for the purpose of producing eggs, meat, and/or feathers. These most typically are members of the superorder Galloanserae , especially the order Galliformes and the family Anatidae , commonly known as "waterfowl"...
on several farm
Farm
A farm is an area of land, or, for aquaculture, lake, river or sea, including various structures, devoted primarily to the practice of producing and managing food , fibres and, increasingly, fuel. It is the basic production facility in food production. Farms may be owned and operated by a single...
s. One death was recorded. Antibodies were found in over half of 500 people tested according to the final official report by the Dutch government:
- As at least 50% of the people exposed to infected poultry had H7 antibodies detectable with the modified assay, it was estimated that avian influenza A/H7N7 virus infection occurred in at least 1000, and perhaps as many as 2000 people. The seroprevalence of H7 antibodies in people without contact with infected poultry, but with close household contact to an infected poultry worker, was 59%. This suggests that the population at risk for avian influenza was not limited to those with direct contact to infected poultry, and that person to person transmission may have occurred on a large scale. Final analysis of Dutch avian influenza outbreaks reveals much higher levels of transmission to humans than previously thought.
In August 2006, low pathogenic (LP) H7N7 was found during routine testing at a poultry farm in Voorthuizen
Voorthuizen
Voorthuizen is a village in the municipality of Barneveld, in the Dutch province of Gelderland. It currently is home to the Seaforth Highlanders of Holland pipe and drum band, a unit founded in 1999 to commemorate the liberation of the village in 1945 by the Seaforth Highlanders of British...
in the central Netherlands. As a precautionary measure, 25,000 chickens were culled from Voorthuizen and surrounding farms.
In June 2008, high pathogenic (HP) H7N7 was confirmed on a 25,000-bird laying unit at Shenington
Shenington
Shenington is a village about west of Banbury. It was an exclave of Gloucestershire until the Counties Act 1844 transferred it to Oxfordshire. Shenington is on Oxfordshire's boundary with Warwickshire.-Manor:...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
; probably derived from a pre-existing low pathogenic variety. "Increased mortality (2.5 per cent in one shed) and a drop in egg production had been recorded two weeks before birds started dying in large numbers on June 2, leading to the diagnosis of HP H7N7 on June 4."
In October 2009, high pathogenic (HP) H7N7 was confirmed on a farm in Almoguera
Almoguera
Almoguera is a municipality located in the province of Guadalajara, Castile-La Mancha, Spain. According to the 2004 census , the municipality has a population of 1,418 inhabitants....
, Guadalajara
Guadalajara (province)
Guadalajara is a province of central/north-central Spain, in the northern part of the autonomous community of Castile-La Mancha. It is bordered by the provinces of Cuenca, Madrid, Segovia, Soria, Zaragoza, and Teruel...
, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
. Hong Kong announced that it would suspend the import of poultry from Spain.
Further reading
- How the Virus Spread from Poultry to People and Pigs
- Comparison of Four H7n7 Avian Influenza Viruses Associated with Infection and Disease in Humans
- WHO
External links
- Influenza Research Database Database of influenza genomic sequences and related information.