This document discusses Avian Reo Virus. It begins with an introduction to the virus's discovery and economic impacts, including weight suppression and viral arthritis. It then covers the virus's characteristics such as being non-enveloped with 10 segments of dsRNA. Transmission occurs horizontally through feces or respiratory routes or vertically at low rates. Clinical signs include lameness, joint swelling, and malabsorption syndrome. Treatment is not possible but vaccination of breeders can help reduce problems in progeny.
Infectious laryngotracheitis (ILT) is an economically important respiratory disease of poultry. This highly contagious disease is caused by Gallid alpha herpesvirus type 1 (GaHV-1), commonly known as infectious laryngotracheitis virus (ILTV). The virus can be easily transmitted by infected birds and fomites. Lax biosecurity, transportation of infected birds, and spread of contaminated litter facilitates spread of the virus. Clinical signs of respiratory disease are not pathognomonic. Diagnosis is by real-time PCR and histopathology . Implementation of biosecurity is necessary for prevention, but vaccination is commonly used for control of the disease in endemic regions worldwide.
Infectious laryngotracheitis (ILT) is an economically important respiratory disease of poultry. This highly contagious disease is caused by Gallid alpha herpesvirus type 1 (GaHV-1), commonly known as infectious laryngotracheitis virus (ILTV). The virus can be easily transmitted by infected birds and fomites. Lax biosecurity, transportation of infected birds, and spread of contaminated litter facilitates spread of the virus. Clinical signs of respiratory disease are not pathognomonic. Diagnosis is by real-time PCR and histopathology . Implementation of biosecurity is necessary for prevention, but vaccination is commonly used for control of the disease in endemic regions worldwide.
Bluetongue is an infectious arthropod-borne viral disease primarily of domestic and wild ruminants. Infection with bluetongue virus (BTV) is common in a broad band across the world, which until recently stretched from ~35°S to 40°–50°N. Bluetongue virus is the type-species of the genus Orbivirus in the family Reoviridae. The geographic restriction is in part related to the climatic and environmental conditions necessary to support the Culicoides vectors.
This color atlas of poultry diseases .This is very useful guide for poultry farmers & poultry practicing professionals.The atlas contains colour photographs demonstrating the overall pathology of birds. The book includes more than 50 diseases from avian infectious pathology and a similar number from non-infectious pathology.There are both classic and well known diseases and new and little known diseases. The book is designed for veterinarians, veterinary students, poultry farmers and poultry specialists.
To get more free guides and literature and books please visit www.growelagrovet.com
Bluetongue is an infectious arthropod-borne viral disease primarily of domestic and wild ruminants. Infection with bluetongue virus (BTV) is common in a broad band across the world, which until recently stretched from ~35°S to 40°–50°N. Bluetongue virus is the type-species of the genus Orbivirus in the family Reoviridae. The geographic restriction is in part related to the climatic and environmental conditions necessary to support the Culicoides vectors.
This color atlas of poultry diseases .This is very useful guide for poultry farmers & poultry practicing professionals.The atlas contains colour photographs demonstrating the overall pathology of birds. The book includes more than 50 diseases from avian infectious pathology and a similar number from non-infectious pathology.There are both classic and well known diseases and new and little known diseases. The book is designed for veterinarians, veterinary students, poultry farmers and poultry specialists.
To get more free guides and literature and books please visit www.growelagrovet.com
Newcastle disease (ND) is a viral disease affecting wild and
domestic birds. It is characterized by a high variability in
morbidity, mortality,
ND primarily affects chickens and turkeys, but most poultry
and many wild and domestic birds are susceptible.
Pseudorabies is an acute, frequently fatal disease with a worldwide distribution that affects swine primarily and other domestic and wild animals incidentally. The pseudorabies virus has emerged as a significant pathogen in the USA since the 1960s, probably because of the increase in confinement swine housing or perhaps because of the emergence of more virulent strains. Clinical signs in nonporcine animals are similar to those of rabies, hence the name “mad itch” (pigs do not display this sign). Pseudorabies is a reportable disease and has been successfully eradicated from the vast majority of the USA.
Erysipelas is an infectious disease mostly of growing or adult swine.
The disease may be acute, subacute, or chronic.
Although acute septicemic swine erysipelas can result in a high mortality rate, the greatest economic loss probably occurs from the chronic, nonfatal forms of the disease.
It may be clinically inapparent, may cause
acute illness
involving many animals, Sudden and unexpected deaths
chronic disease characterized by
enlarged joints, lameness, and endocarditis.
Rhomboid skin (diamond-skin) lesions are an inconsistent feature only associated with acute cases
البوست ده عمل خيري ...
دي لينكات لمحاضرات في امراض وادوية الدواجن وكورسات التنمية البشرية ... جميع المحاضرات بصيغة بوربوينت
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Links to PowerPoint presentations in poultry diseases, medications, and immunity in addition to soft skills courses
Share to benefit others
ادوية علاج الدواجن من المضادات الحيوية ومستخلصات الأعشاب
Poultry medications (antibiotics and herbal extracts)
Link to download more presentations in powerpoint
https://lnkd.in/gJGGnPY
امراض الدواجن البكتيرية والفيروسية واساسات التحصينات ومناعة الطيور
Poultry diseases, vaccination and immunity
Link to download presentations in powerpoint
https://lnkd.in/g2ef7DP
كورسات التنمية البشرية
Soft skills courses
Link to download presentations in powerpoint
https://lnkd.in/g8W7TYq
Presentations are continuously updated
المكتبة متجددة باستمرار
البوست ده عمل خيري ...
دي لينكات لمحاضرات في امراض وادوية الدواجن وكورسات التنمية البشرية ... جميع المحاضرات بصيغة بوربوينت
شير لعلها تكون المنجية لنا جميعا
This post is for charity ...
Links to PowerPoint presentations in poultry diseases, medications, and immunity in addition to soft skills courses
Share to benefit others
ادوية علاج الدواجن من المضادات الحيوية ومستخلصات الأعشاب
Poultry medications (antibiotics and herbal extracts)
Link to download more presentations in powerpoint
https://lnkd.in/gJGGnPY
امراض الدواجن البكتيرية والفيروسية واساسات التحصينات ومناعة الطيور
Poultry diseases, vaccination and immunity
Link to download presentations in powerpoint
https://lnkd.in/g2ef7DP
كورسات التنمية البشرية
Soft skills courses
Link to download presentations in powerpoint
https://lnkd.in/g8W7TYq
Presentations are continiously updated
المكتبة متجددة باستمرار
Seven Cs of Effective Communication_Life Time Example.pptxOssama Motawae
"عسى ان يكون علما ينتفع به"
Communication
دي لينكات لمحاضرات في امراض وادوية الدواجن وكورسات التنمية البشرية ... جميع المحاضرات بصيغة بوربوينت
ادوية علاج الدواجن من المضادات الحيوية ومستخلصات الأعشاب
Poultry medications (antibiotics and herbal extracts)
Link to download more presentations in PowerPoint
https://drive.google.com/open?id=1EtFtygmlvOYqjqpanRTIgoExIENd-YIB
امراض الدواجن البكتيرية والفيروسية واساسات التحصينات ومناعة الطيور
Poultry diseases, vaccination, and immunity
Link to download presentations in PowerPoint
https://drive.google.com/open?id=1znC0qeHMivV2ai4_IUweA-VTBQLJSVKu
كورسات التنمية البشرية
Soft skills courses
Link to download presentations in PowerPoint
https://drive.google.com/open?id=1R3CqcFO10bOyi1aRQx0WNSn6B5TMNMxu
Seven Cs of Effective Communication_Tips.pptxOssama Motawae
"عسى ان يكون علما ينتفع به"
Communication
"عسى ان يكون علما ينتفع به"
Communication
دي لينكات لمحاضرات في امراض وادوية الدواجن وكورسات التنمية البشرية ... جميع المحاضرات بصيغة بوربوينت
ادوية علاج الدواجن من المضادات الحيوية ومستخلصات الأعشاب
Poultry medications (antibiotics and herbal extracts)
Link to download more presentations in PowerPoint
https://drive.google.com/open?id=1EtFtygmlvOYqjqpanRTIgoExIENd-YIB
امراض الدواجن البكتيرية والفيروسية واساسات التحصينات ومناعة الطيور
Poultry diseases, vaccination, and immunity
Link to download presentations in PowerPoint
https://drive.google.com/open?id=1znC0qeHMivV2ai4_IUweA-VTBQLJSVKu
كورسات التنمية البشرية
Soft skills courses
Link to download presentations in PowerPoint
https://drive.google.com/open?id=1R3CqcFO10bOyi1aRQx0WNSn6B5TMNMxu
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
2. Plan of Talk
Introduction
Economic importance
Virus characteristics
Transmission
Clinical sings and PM lesions
Treatment and control
3. Plan of Talk
Introduction
Economic importance
Virus characteristics
Transmission
Clinical sings and PM lesions
Treatment and control
4. Introduction
1954
The initial avian reovirus was isolated by Fahey and Crawley
from the respiratory tract of chickens.
1957
Olsen et al. Isolated a reovirus from chickens with naturally
occurring synovitis that were unrelated to MG or MS.
Late 70s – early 80s
Nonspecific malabsorption syndrome due to avian reovirus
was described.
5. Cont. …
Avian reo viruses are ubiquitous viruses in nature.
They are commonly isolated from a variety of tissues in
poultry affected by multiple disease conditions such as:
1. Viral arthritis/tenosynovitis.
2. Stunting syndrome.
3. Respiratory disease.
4. Enteric disease.
5. Malabsorption syndrome.
6. Cont. …
Reovirus infections are prevalent
worldwide in chickens and turkeys.
Viral arthritis/tenosynovitis is found
primarily in meat-type chickens and
turkeys.
Reoviruses are commonly found in the
digestive and respiratory tracts of
clinically normal chickens and turkeys.
9. Cont. …
10-30% weight suppression, without
complications.
Up to 50% weight suppression, when
complicated with other stressors.
10. Plan of Talk
Introduction
Economic importance
Virus characteristics
Transmission
Clinical sings and PM lesions
Treatment and control
11. Economic Importance
Reovirus-associated Diseases;
1. Weight suppression (malabsorption)
Infections in the first week of age.
2. Viral arthritis/ tenosynovitis
Infections in naive birds (any age, but especially young).
3. Runting & stunting syndrome
– Infections in the first week, reovirus + other agent(s).
– Femoral head necrosis, brittle bone disease, acute mortality.
4. Respiratory disease.
5. Enteric disease.
6. Immune suppression.
12. Cont. …
Broiler
1. Increase mortality.
2. Viral arthritis and tenosynovitis.
3. General lack of performance;
1. Diminished weight.
2. Poor feed conversion.
3. Uneven growth rate.
4. Reduce marketability of affected birds.
13. Cont. …
Breeder
(viral arthritis prior to the onset or during egg production)
1. Lameness.
2. Increased mortality.
3. Decrease egg production.
4. Suboptimal hatchability and fertility.
5. Vertical transmission to progeny.
14. Plan of Talk
Introduction
Economic importance
Virus characteristics
Transmission
Clinical sings and PM lesions
Treatment and control
16. Cont. …
Persistent pathogen:
1. Resistant to high temp 60c for 8 hrs.
2. Tolerates pH 3-9.
3. Non sensitive either.
4. Slight sensitive for chloroform.
5. The virus can survive for up to 10 days on feathers, wood
shavings, glass, rubber and galvanized metal, and for 10
weeks in water, with limited effect on infectivity.
18. Virus Target Tissue
The epithelial cells of:
1. Small intestine
2. Bursa of Fabricius
are the main sites of primary infection
and portal of entry of the virus which
rapidly spreads to other organs within
24-48 hours of infection.
19. Cont. …
The site where virus replication has the most serious
consequences is the tibiotarsal-tarsometatarsal (hock) joint.
At this site, the virus replication and long-term persistence
induce a series of processes leading to joint damage and in
the most severe cases, tendon rupture.
20. Virus Kinetics
Experimental infection of adult SPF hens via the nasal,
tracheal or esophageal routes, showed distribution of virus to
all areas of the respiratory, enteric and reproductive tracts
and the tendon of the hock joints (viraemia).
21. Cont. …
The virus was recovered from the plasma, erythrocyte and
mononuclear cell fractions of blood within 30 hours.
By 3 to 5 days, virus had been distributed throughout the
body.
Despite this widespread tissue dissemination, the principal
site of virus replication is the enteric tract.
22. Plan of Talk
Introduction
Economic importance
Virus characteristics
Transmission
Clinical sings and PM lesions
Treatment and control
23. Transmission
1. Vertical transmission, occurs at a low rate.
2. Most chicks become infected at an early age from:
Small nucleus of congenitally infected hatch-mates.
Environment.
24. Cont. …
Horizontal transmission
1. Intestinal tract (fecal contamination)
2. Respiratory tract.
3. Age related resistance.
4. Reoviruses may enter broken skin of the feet of chicks from
the litter and become established in the hock joints.
Vertical Transmission
1. Egg transmission low (<2.0%)
2. Hens infected via oral, tracheal, and nasal inoculation were
able to transmit reovirus to their progeny.
25. Plan of Talk
Introduction
Economic importance
Virus characteristics
Transmission
Clinical sings and PM lesions
Treatment and control
26. Clinical Signs – Post Mortem lesions
Viral arthritis/tenosynovitis
Viral arthritis/tenosynovitis
The first signs of reovirus infection are usually observed in
broiler breeder chickens between 6 and 10 weeks of age.
Broilers
27. Cont. …
1. Lameness.
– Birds are reluctant to walk and
when forced up have a painful,
trembling gait.
2. Joint swelling.
– A distinct swelling of the
tendons of the shanks and also
above the hock joint can be
observed.
3. Thickened/ruptured tendons. Swollen tendons
28. Cont. …
4. Affected birds have malpositioned
feathers, especially on the wings.
Malpositioned feather
29. Cont. …
5. The hock joint may be somewhat swollen, but usually not as
severely as with Mycoplasma synoviae or Staphylococcus
infections.
6. Upon opening the legs, the tendons usually appear
discolored, brown or blood-tinged, with straw colored fluid
between them.
30. Cont. …
7. Ruptured tendons may occur and, in older broiler breeders
(29-30 weeks old), one may feel a hard scarry knot in the
tendon above the hock joint.
8. When the infection is complicated by MS or Staphylococcus,
the fluid may appear yellow and creamy.
31. Clinical Signs – Post Mortem lesions
Malabsorption Syndrome
The disease is mainly observed
in broiler flocks.
32. Cont. …
1. History of diarrhea, beginning at few days of age and lasting
until 10-14 days of age.
– Light or dark brown, foamy droppings can be found with undigested
food particles.
2. Runting/Stunting.
3. Abnormal feathering.
– Several affected broilers in a flock may exhibit malpositioned feathers,
especially on the wings.
33. Cont. …
4. Skeletal abnormalities.
– Early rickets with extreme paleness of legs and heads can be
observed.
5. At a later age (5-6 weeks) osteoporosis becomes clinically
evident.
– Frequently unilateral causing the birds to limp.
6. Delayed growth of the affected birds.
7. Mortality is variable and in general as low as 4 %.
34. Plan of Talk
Introduction
Economic importance
Virus characteristics
Transmission
Clinical sings and PM lesions
Treatment and control
35. Treatment and Control
Treatment is impossible.
Vaccinating breeders helps reduce problems in the progeny.
Strict hygienic and sanitary measures will reduce the
incidence of the disease.
36. Purpose of Vaccination
1. Prevent infection of breeders.
2. Prevent egg transmission to progeny.
3. Produce maternal antibodies for the progeny.
Layers
37. Time of Vaccination
Broiler progeny need high MDA to prevent early infections,
Infection before 7 days leads to malabsorption, runting
and stunting.
Infection before 14 days leads to leg problems (FHN and
ruptured tendons).
38. Vaccination Program
For the development and persistence of high levels of maternal
antibody, Giambrone recommended the use of:
1. Live vaccine as a primer early in life.
2. Inactivated vaccine given at 6 weeks of age and again
prior to lay.
39. Cont. …
In areas of high exposure
Chicks are susceptible during the first weeks of life, and early
vaccination becomes mandatory.
In these areas, vaccination should begin at 7 days of age.
Re-vaccination is recommended at 5 to 7 weeks of age and
again at 9 to 11 weeks.
40. Cont. …
In areas where there is less exposure
Vaccination should be carried out at 5 to 7 weeks of age and
again at 9 to 11 weeks.
To complete this program for breeding birds, the
administration of an inactivated Reovirus vaccine is
recommended between 16 to 18 weeks of age.
41. Vaccine Strains
Strain Association Live/Killed
S1133 Tenosynovitis Live and Killed
UMI 203 Tenosynovitis Live
2408 Malabsorption/Tenosynovitis Killed
1733 Malabsorption/Tenosynovitis Killed
CO8 Malabsorption Syndrome Killed
305 Malabsorption/FHN/BBD Killed
ss412 Malabsorption/proventriculitis Killed
42. Virus Strains
Strain Disease or Syndrome Signs and Symptoms
1133
Causes tenosynovitis (VA), an
infection of the synovial sheath of
the tendon.
Leg and or joint swelling, difficult
in walking and bruised
appearance of the leg and thigh
muscles due to tendon rupture.
2408
Associated with VA and
Malabsorption Syndrome (MAS), a
condition where nutrients are not
absorbed in the intestine.
Early mortality, reduced weight
gains, poor feathering, poor
pigmentation, runting and
stunting.
3005
Associated with MAS, femoral
head Necrosis (FHN), and brittle
bone disease.
Deterioration of the top of the
thigh bone can be seen during a
post mortem examination.
44. Why do we use live vaccines for REO virus?
Are they used just as a primer or do they protect
vaccinated birds against symptoms?
45. Live REO vaccines can induce protection against symptoms in
young birds, but only when there are no maternally-derived
antibodies (MDA) present to neutralize the vaccine.
Vaccines will not be effective in young birds with MDA against
REO.
Early REO infections are the most dangerous ones.
The most effective protection against them is by inducing high
levels of antibodies in the parent stock, to protect the
offspring by MDA.
46. High antigen content inactivated REO vaccines are the most
effective, inducing high titres in parent stock.
Priming such parent flocks with a live REO vaccine will further
increase the effect of the inactivated REO vaccine.
Individual and average titres are higher and more uniform.
Most importantly, the percentage of breeder birds that has
low or zero titres diminishes.
This live priming of the young breeder birds can be done
when MDA have waned (after approximately six weeks of
age).
47. Mal-absorption syndrome (MAS) is still a current
problem in broiler flocks worldwide. Can it be
minimized by REO virus vaccination of parent stock?
48. MAS is a complex of symptoms occurring when the intestines
of the broiler are not able to absorb sufficient nutrients,
resulting in deficiencies and growth retardation.
Certain REO strains cause MAS like symptoms.
This does not mean that all MAS is caused by REO infections:
Any pathogen that disturbs the optimal balance in the intestinal flora,
can cause symptoms of MAS.
In cases of MAS caused by REO infections, REO vaccination of the
parent stock is the most effective way of prevention.
49. Are different strains of REO virus responsible for
different symptoms or syndromes in the infected
birds?
Why do some inactivated vaccines contain different
REO virus strains?
50. REO virus isolates have been associated with a great variety of
symptoms.
This has enabled the categorization of REO-related infections
into different syndromes such as:
1. Viral arthritis (VA)
2. Brittle bone syndrome
3. Mas
4. Runting/stunting syndrome
5. Helicopter disease.
51. The S1133 (Lvd-Heijden) strain is reported to be isolated from
a case of VA.
The 1733 strain is isolated from a case of classic MAS.
The 3005 from a case of brittle bone.
52. However, a REO isolate from one specific syndrome will not
necessarily always cause similar symptoms.
Neither is it possible to differentiate various isolates by
current serological methods: the REO antibodies do not make
a distinction.
In fact, the immune system does not distinguish between the
one and the other pathotype: antibodies induced by one
isolate will protect equally against the other pathotypes.
Inclusion of isolates of two or more syndromes in a vaccine
does not give a broader protection.
53. Moreover, it would be un-practical to include isolates of all
syndromes, associated with REO virus infections.
However, including more antigen per dose can increase the
immune response, measured in titers.
A higher titer sometimes can induce a more effective
protection, which in itself could induce a higher titer and a
better protection.