Reovirus in Chickens

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Questions and Answers

What clinical sign was first associated with reoviruses in 1957?

Viral arthritis (VA).

List two diseases associated with reoviruses besides viral arthritis.

Malabsorption syndrome (MAS) and femoral head necrosis (FHN).

What type of virus are reoviruses classified as?

Double-stranded RNA viruses.

How long can reoviruses remain viable in culture at 72°F?

Almost a year. Signup and view all the answers

What effect does reovirus have on tendons and joints?

It causes inflammation that can lead to arthritis or tenosynovitis. Signup and view all the answers

What consequence does reovirus-induced malabsorption have on chickens?

Poor growth and skeletal abnormalities. Signup and view all the answers

Why are heavy chicken breeds more susceptible to reovirus-related tendon diseases?

They grow rapidly, predisposing them to physical changes in leg tendons. Signup and view all the answers

How much longer do broiler breeds take to respond serologically to reovirus infections compared to other breeds?

Approximately one week longer. Signup and view all the answers

What factor contributes to the greater susceptibility of heavy breed birds to reovirus infections?

The delay in immune response contributes to greater susceptibility. Signup and view all the answers

In which demographic of chickens is reovirus-associated viral arthritis observed more frequently?

It is seen more frequently in males than females. Signup and view all the answers

What are some of the economic impacts associated with reovirus-associated diseases in poultry?

Diseases like viral arthritis, malabsorption syndrome, brittle bone, and femoral head necrosis have economic impacts. Signup and view all the answers

What age group of chickens is clinically observed for tenosynovitis?

Tenosynovitis is observed in chickens aged five to eight weeks and in mature breeders over 20 weeks. Signup and view all the answers

What is a common consequence of malabsorption syndrome in young birds?

Common consequences include poor feed conversions and decreased marketability. Signup and view all the answers

What transient effect do selected reoviruses cause in young birds?

They cause transient immunodepression and bursal lymphoid depletion. Signup and view all the answers

Why is it challenging to categorize the hundreds of isolated reoviruses into distinct serotype categories?

It is challenging due to their varying abilities to cause disease and cross protect. Signup and view all the answers

What is generally observed in more pathogenic reoviruses when introduced into unprotected broilers?

More pathogenic reoviruses produce higher mortality rates and induce a more consistent antibody response. Signup and view all the answers

What economic impacts does Runting-Stunting Syndrome (RSS) have on the broiler industry?

RSS causes decreased body weights, elevated feed conversions, reduced uniformity, reduced livability, and secondary diseases. Signup and view all the answers

Which pathogens may be involved in the etiology of RSS?

Pathogens include several viruses such as reovirus, adenovirus, enterovirus, rotavirus, and bacteria like E. coli and Staphylococcus cohnii. Signup and view all the answers

At what age do symptoms of RSS typically peak in affected birds?

Symptoms and mortality typically peak at around 11 days of age. Signup and view all the answers

Describe two observable behaviors of birds affected by RSS.

Affected birds may huddle around feeders and waterers or persistently peck at the walls. Signup and view all the answers

What is helicopter disease, and how is it characterized in birds with RSS?

Helicopter disease is characterized by smaller, curled feathers at the wing tips of affected birds. Signup and view all the answers

What are the necropsy findings typically observed in birds with RSS?

Necropsied birds generally have small livers and enlarged gall bladders. Signup and view all the answers

What is the impact of RSS on flock uniformity?

Flock uniformity decreases from about 70% to about 35% due to RSS. Signup and view all the answers

How might the legs and beak of birds affected by RSS appear?

The legs and beaks of affected birds may appear pale in color. Signup and view all the answers

What are the characteristics of the intestines of birds affected by RSS?

They appear thin, translucent, and may be enlarged with large amounts of fluids and poorly digested feed. Signup and view all the answers

What happens to the pancreas of birds suffering from RSS?

The pancreas degenerates and there is a reduction in digestive enzymes. Signup and view all the answers

What are the symptoms observed in droppings from birds with RSS?

The droppings are unusually loose, and the vents are soiled. Signup and view all the answers

At what age do symptoms and mortality from RSS peak in birds?

Symptoms and mortality peak at about 11 days old. Signup and view all the answers

What are the three primary areas to focus on for controlling RSS?

Biosecurity, good poultry house management, and vaccination. Signup and view all the answers

Why is it important to manage farm visitors in the context of RSS control?

Controlling farm visitors reduces the possibility of exposure to the disease. Signup and view all the answers

What cleaning and management practices should be followed before placing chicks in a brood chamber?

The brood chamber should be thoroughly cleaned and disinfected, and a minimum of 12 days of downtime should be allowed. Signup and view all the answers

How can supplemental vitamins and minerals aid chicks in dealing with RSS?

They improve the immunity of chicks and their ability to cope with RSS. Signup and view all the answers

Study Notes

Reovirus

Reoviruses were identified in 1957 in chickens, causing viral arthritis (VA)
Associated with various conditions: malabsorption syndrome (MAS), femoral head necrosis (FHN), pericarditis, myocarditis, hydropericardium, gastroenteritis, hepatitis, acute and chronic respiratory syndromes
Double-stranded RNA viruses
Highly resistant to physical and chemical inactivation, and low pH
Similar to Infectious Bursal Disease Virus
Remain infective in contaminated environments for long periods (almost a year at 72°F)
Minimal impact on reovirus population in systems with a two-week litter turn-around time
Cause inflammation in tendons, reducing tensile strength, leading to arthritis or tenosynovitis
Results in lameness and stunting in chickens
Associated with nutrient malabsorption syndrome, causing poor growth and skeletal abnormalities linked to intestinal, pancreatic or liver issues
Affects both heavy and light breeds, with heavy breeds being more susceptible to tendon-related diseases due to rapid growth and less tensile strength in leg tendons. A delayed response to reoviral infections also contributes to this susceptibility.
Worldwide impact on poultry industry with diseases including viral arthritis (VA), malabsorption syndrome (MAS), brittle bone (BB), and femoral head necrosis (FHN)
Tenosynovitis is observed in young chickens (five to eight weeks), and mature breeders, causing higher mortality and lower quality broilers/roosters.

Runting-Stunting Syndrome (RSS)

Economic hardship in broiler industry due to decreased body weights, elevated feed conversions, reduced uniformity, reduced livability, and plant downgrades
Complex etiology, not fully understood, likely involved viruses, bacteria, and other pathogens.
Reovirus was initially suspected but other viruses (adenovirus, enterovirus, rotavirus, parvovirus,) and bacteria are also considered.
Common bacteria found in affected birds include E. coli, Proteus micabilis, Enterococcus faecium, Staphylococcus cohnii, Clostridium perfringes, Bacteroides fragilis, and Bacillus licheniformis
Symptoms vary but commonly affect birds early in life (around 11 days), exhibiting symptoms like huddling, persistent pecking at walls, decreased feed consumption, and mortality
Often sudden onset and cessation, making control difficult.
Control measures should focus on early stages of the flock's life.

Biosecurity and Vaccination

Tighten biosecurity procedures to reduce exposure and slow spread
Proper management of mortality disposal, vermin control (rodents, wild birds, insects), and visitor control
Maintain a stress-free environment for birds.
Minimize time between flocks (at least 12 days of downtime)
Remove litter if birds are diagnosed with RSS
Thoroughly clean and disinfect brood chambers
Vaccination for reovirus is prevalent, achieved through maternal antibodies and vaccination if needed
Maternal antibodies offer variable protection, lasting a time depending on the hen's antibody titer when laying the egg.
A highly attenuated vaccine can be given when maternal antibodies are depleted (7-14 days) and gives protection for 5-6 weeks
Two vaccinations (priming and boosting) are used for improved immunity and prevention of vertical transmission.

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Description

This quiz explores the impact of reoviruses on chickens, focusing on conditions such as viral arthritis and malabsorption syndrome. Understand the characteristics of these double-stranded RNA viruses and their resistance to environmental factors. Test your knowledge on how reoviruses affect both heavy and light breeds and the associated health issues.