Avian virus new to Thailand found on chicken farms

[Gert van der Hoek]

POULTRY DISEASE THREAT

Avian virus new to Thailand found on chicken farms


An avian virus that is new to Thailand has been found in chicken farms in the central, western, and eastern regions, raising serious concerns about its impact on the country's poultry industry.

The discovery of the virus, Avian Adenovirus Group 1, was revealed yesterday by a team of veterinarians from Kasetsart University's veterinary medicine's diagnostic unit in Nakhon Pathom province.

The unit maintained that the virus, which causes inclusion body hepatitis in poultry, could not be transmitted to humans. Chicken meat and eggs are also safe to eat.


The virus was detected in breeder chicks, aged 3-7 days, which looked drowsy and exhausted. Many of them suffered convulsions and died in 12 hours. The chicks were sent to the unit for examination in April.


The deaths wiped out 10-15% of the flocks. In these cases, the disease lasted for a week and the surviving chicks' growth was stunted.


The disease broke out at six chicken farms in the three regions earlier this year. The spread of the virus had been contained at all of them, said Taweesak Songserm, the team leader.


Besides young chickens, the disease can be found in pigeons, geese, turkeys and partridges. Possible disease carriers include rats, flies and cockroaches.


The disease takes three to seven days to incubate and the symptoms become apparent in three weeks. The university urged chicken farmers to keep a watchful eye on their flocks.


Bird flu prevention and surveillance operations can be applied to combat the spread of the virus on chicken farms, the veterinarians said.


The virus causes weak egg shells. Chickens hatching from such weak eggs would become ill in three weeks.


Besides transmission from mother to baby chick via the egg, the disease could be transmitted between chickens via virus-contaminated food and drinks and farm equipment.


A test showed disinfectants in the glutaraldehyde category and effective disposal of infected nest floors could help contain the virus

http://www.bangkokpost.com/181008_News/18Oct2008_news03.php

 

[Giuseppe]

Re: Avian virus new to Thailand found on chicken farms

Some details about this pathogen:


Group I avian adenovirus and avian adeno-associated virus in turkey poults with inclusion body hepatitis

Authors: Shivaprasad H.L.; Woolcock P.R.; McFarland M.D.

Source: Avian Pathology, Volume 30, Number 6, 1 December 2001 , pp. 661-666(6)

Publisher: Taylor and Francis Ltd

Abstract:
Adenoviral inclusion body hepatitis (IBH) is rare in turkeys.
Avian adenovirus group I and avian adeno-associated virus were isolated from the liver and pooled intestinal samples from 4-week-old turkey poults on two different ranches experiencing increased mortality.
Grossly, a few birds from each ranch had a slightly enlarged liver with white foci of necrosis randomly scattered throughout.
Microscopically, there was coagulative necrosis of hepatocytes with infiltration of a mixed population of inflammatory cells composed of lymphocytes, plasma cells, heterophils, and macrophages.
In these livers, there were numerous basophilic intranuclear inclusion bodies in the hepatocytes.
Transmission electron microscopy of the liver revealed 70 to 75 nm viral particles with icosahedral morphology consistent with adenovirus scattered throughout the nucleus of hepatocytes.
All of the birds were serologically negative for haemorrhagic enteritis virus infection.
Of some 5000 submissions over a 12-year period of turkey poults aged between 1 day and 10 weeks, only two single birds within two submissions had IBH.
-
http://www.ingentaconnect.com/content/tandf/cavp/2001/00000030/00000006/art00009
------

 

[Gert van der Hoek]

Re: Avian virus new to Thailand found on chicken farms

This virus doesn't seem to be a serious threat to humans; for chickens it is regarded as "mild".

Respiratory Adenovirus Infection, 'Mild Respiratory Disease'

Extracted From:

A Pocket Guide to
Poultry Health
and
Disease

By Paul McMullin


Introduction

An adenovirus infection of chickens with a morbidity of 1-10% and a mortality of 1-10%; at least 12 sero-types have been described and these may be isolated from healthy chickens. Infected birds may remain carriers for a few weeks. Transmission may be vertical and lateral, and by fomites.

The virus is generally resistant to disinfectants (ether, chloroform, pH), temperature, formaldehyde and iodides work better. Opinions vary as to whether adenovirus can be characterised as a primary respiratory pathogen. It may occur as an exacerbating factor in other types of respiratory disease.

Signs

Mild snick and cough without mortality.

Post-mortem lesions

Mild catarrhal tracheitis.

Diagnosis
History, lesions, intranuclear inclusions in liver. The virus grows well in tissue culture (CE kidney, CE liver).

Treatment
None.

Prevention
Quarantine and good sanitary precautions, prevention of immunosuppression.

http://www.thepoultrysite.com/disea...adenovirus-infection-mild-respiratory-disease

 

[Treyfish]

Re: Avian virus new to Thailand found on chicken farms

INCLUSION BODY HEPATITIS, POULTRY - THAILAND
********************************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>

Date: Sat 18 Oct 2008
Source: Bangkok Post [edited]
<http://www.bangkokpost.com/topstories/topstories.php?id=131488>


Fowl new virus
--------------
An avian virus that is new to Thailand has been found in chicken
farms in the central, western, and eastern regions, raising serious
concerns about its impact on the country's poultry industry. The
discovery of the virus, Avian Adenovirus Group 1, was revealed
yesterday by a team of veterinarians from Kasetsart University's
veterinary medicine's diagnostic unit in Nakhon Pathom province. The
unit maintained that the virus, which causes inclusion body hepatitis
in poultry, could not be transmitted to humans. Chicken meat and eggs
are also safe to eat.

The virus was detected in breeder chicks, aged 3-7 days, which looked
drowsy and exhausted. Many of them suffered convulsions and died in
12 hours. The chicks were sent to the unit for examination in April.
The deaths wiped out 10 to 15 percent of the flocks. In these cases,
the disease lasted for a week and the surviving chicks' growth was stunted.

The disease broke out at 6 chicken farms in the 3 regions earlier
this year [2008]. The spread of the virus had been contained at all
of them, said Taweesak Songserm, the team leader.

Besides young chickens, the disease can be found in pigeons, geese,
turkeys and partridges. Possible disease carriers include rats, flies
and cockroaches. The disease takes 3 to 7 days to incubate and the
symptoms become apparent in 3 weeks. The university urged chicken
farmers to keep a watchful eye on their flocks.

Bird flu prevention and surveillance operations can be applied to
combat the spread of the virus on chicken farms, the veterinarians
said. The virus causes weak egg shells. Chickens hatching from such
weak eggs would become ill in 3 weeks. Besides transmission from
mother to baby chick via the egg, the disease could be transmitted
between chickens via virus-contaminated food and drinks and farm equipment.

A test showed disinfectants in the glutaraldehyde category and
effective disposal of infected nest floors could help contain the virus.

--
Communicated by:
ProMED-mail Rapporteur Mary Marshall

[Adenoviruses are widespread throughout all avian species. Studies
have demonstrated the presence of antibodies in healthy poultry, and
viruses have been isolated from normal birds. Despite their
widespread distribution, the majority of adenoviruses cause no or
only mild disease; however, some are associated with specific
clinical conditions. Avian adenoviruses (AAV) in chickens are the
etiologic agents of 2 important diseases known as inclusion body
hepatitis (IBH) and hydropericardium syndrome (HP). Although in some
cases each condition is observed separately, during the last decade
the 2 conditions have been frequently observed as a single entity;
therefore, the name hepatitis hydropericardium has been widely used
to describe the pathologic condition. The syndrome is an acute
disease of young chickens associated with anemia, hemorrhagic
disorders, and hydropericardium. It is a common disease in several
countries, where broilers are severely affected, resulting in high
mortality rates.

Etiology, Transmission, and Pathogenesis:
-----------------------------------------
The AAV of group I are the etiologic agents of this condition.
Although there are 12 different serotypes of AAV, the most common
viruses isolated in cases of IBH/HP belong to serotypes 4 and 8.
These AAV are capable of producing the disease without the
immunosuppressive effects of associated viruses such as infectious
bursal disease (IBDV, Infectious Bursal Disease) or other
immunosuppressive agents. However, the association with
immunosuppressive viruses such as IBDV and chicken anemia virus (CAV,
Chicken Anemia Virus Infection) will result in a more severe disease.

Horizontal and vertical transmission play an important role in
IBH/HP. Vertical transmission has been described in progeny from
breeder flocks infected with AAV serotypes 4 and 8. Horizontal
transmission has also been demonstrated; young chicks in contact with
infected chicks can die of peracute IBH/HP. Chicks and young chickens
are commonly affected. Infection with some strains of AAV may result
in minimal hepatic disease; however, if birds have been infected with
immunosuppressive viruses (IBD, CAV, Marek's disease), the clinical
disease becomes evident.

Clinical Findings, Lesions, and Diagnosis:
------------------------------------------
Sudden mortality usually is seen in chickens <6 wk old and as young
as 4 days of age. Mortality normally ranges from 2-40 percent,
especially when birds are <3 wk of age. However, there have been
outbreaks in which mortality has reached 80 percent. Mortality rates
also vary depending on the pathogenicity of the virus and infection
with other viral or bacterial agents. Signs associated with diseases
caused by other pathogens (e.g., bacteria, fungi, or viruses)
commonly occur if birds are immunosuppressed.

Flocks of 3- to 5-wk-old broilers with HP may not show specific
clinical signs, but abrupt onset of mortality, lethargy, huddling
with ruffled feathers, and yellow, mucoid droppings may be seen. The
duration of the infection usually ranges from 9-14 days with
morbidity of 10-30 percent and a daily mortality of 3-5 percent.
Gross lesions include up to 10 mL of a straw-colored transudate in
the pericardial sac, generalized congestion, and an enlarged, pale,
friable liver. Histopathologic lesions include myocardial edema in
the heart with degeneration, necrosis, and mild mononuclear cell
infiltration. Basophilic intranuclear inclusion bodies may be present
in the liver. A tentative diagnosis is based on typical microscopic
findings and confirmed by isolating adenoviruses from the liver.
Serology, restriction enzyme analysis and PCR are used to classify
adenoviruses isolated from clinical cases. This information is used
for epidemiologic studies.

Treatment and Prevention:
-------------------------
As with many other viral diseases, there is no treatment. Antibiotics
may help prevent secondary bacterial infections. Sulfonamides are
contraindicated if evidence of hematologic disease or
immunosuppression is seen.

Vaccines against IBH/HP are not commercially available in the USA;
however, in other countries both live and inactivated vaccines are
used to control the syndrome. The AAV serotypes most frequently used
to prepare commercial vaccines are serotypes 4 and 8. Primary
breeders with stringent biosecurity practices sometimes use
autogenous inactivated vaccines to ensure the transfer of maternal
immunity from breeding flocks to their progeny. In Australia, a live
vaccine given via drinking water was developed for breeders between
10-14 wk of age. In other countries, including Mexico, Pakistan, and
Peru, inactivated vaccines are routinely used to vaccinate breeders
and broilers. When breeders are properly vaccinated, antibodies
generated by the vaccine are transmitted to the progeny, providing
protection against field infections and clinical disease. Broilers
are vaccinated at <10 days of age when their parents either do not
have serotype-specific adenovirus antibodies or maternal antibody
transmission is erratic due to improper vaccination procedures that
result in a substantial number of unvaccinated birds.

The above chapter on Inclusion Body Hepatitis/hydropericardium
Syndrome (Hepatitis hydropericardium) is derived from the Merck
Veterinary Manual at
<http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/200400.htm&word=inclusion%2cbody%2chepatitis>.
- Mod.AS]

[A map showing the location of Thailand is available at:
<http://www.worldatlas.com/webimage/countrys/asia/th.htm> - CopyEd.EJP]

[see also:
2003
----
Inclusion body hepatitis, poultry - Bolivia 20030111.0094]
....................mpp/arn/ejp/mpp
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