Changes

== Clinical Signs  ==

== Clinical Signs  ==

LPAI viruses cause milder disease, most commonly respiratory symptoms (e.g. rales, coughing) combined with reduced egg production and depression, though clinical signs can range from none to death. Other signs can include swelling of the infraorbital sinuses, pyrexia and loss of appetite. If other bacteria or viruses (e.g. ''[[Pasteurella species|Pasteurella spp]], [[Newcastle Disease Virus|Newcastle disease]], [[Mycoplasma gallisepticum|Mycoplasma spp]], [[Escherichia coli]]'') are present along with LPAI the consequences of infection can be more serious, often causing high mortality. The age, immune status and species of the infected bird can also have an impact on the severity of disease, as can the environment the bird is housed in. Many flocks are infected with LPAI every year and are only recognised due to seroconversion as the disease is asymptomatic. Most infections are transient due to lack of host adaptation, though some establish due to virus variation.

LPAI viruses cause milder disease, most commonly respiratory symptoms (e.g. rales, coughing) combined with reduced egg production and depression, though clinical signs can range from none to death. Other signs can include swelling of the infraorbital sinuses, pyrexia and loss of appetite. If other bacteria or viruses (e.g. ''[[Pasteurella species|Pasteurella spp]]'', [[Newcastle Disease Virus|Newcastle disease]], ''[[Mycoplasma gallisepticum|Mycoplasma spp]]'', ''[[Escherichia coli]]'') are present along with LPAI the consequences of infection can be more serious, often causing high mortality. The age, immune status and species of the infected bird can also have an impact on the severity of disease, as can the environment the bird is housed in. Many flocks are infected with LPAI every year and are only recognised due to seroconversion as the disease is asymptomatic. Most infections are transient due to lack of host adaptation, though some establish due to virus variation.

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By contrast, HPAI infection may only be recognised by sudden onset mortality within the flock, which can reach 100% within a couple of days.  If the birds are still alive symptoms can include those of LPAI (though egg laying has often stopped) and excessive lacrimation, sinusitis, oedema of the head, subcutaneous haemorrhage, cyanosis of the skin (including comb and wattles), diarrhoea and occasional neurological signs.  Severity of signs depends on the species and strain of the virus, for example some ducks infected with HPAI rarely showed clinical signs.

By contrast, HPAI infection may only be recognised by sudden onset mortality within the flock, which can reach 100% within a couple of days.  If the birds are still alive symptoms can include those of LPAI (though egg laying has often stopped) and excessive lacrimation, sinusitis, oedema of the head, subcutaneous haemorrhage, cyanosis of the skin (including comb and wattles), diarrhoea and occasional neurological signs.  Severity of signs depends on the species and strain of the virus, for example some ducks infected with HPAI rarely showed clinical signs.