Secondary Infection after Infectious Bronchitis, Became more of an issue than the IB itself

Many single IBV infections cause mild respiratory signs, relatively decreased body weight, and slightly higher mortality rates. Some broiler flocks experienced IBV infections diagnosed molecularly by real-time PCR and serologically by using ELISA (2x increase of mean antibody titer than expected), the cumulative mortality rate doesn't exceed 8%.

IBV infection complicated with H9 AIV infection resulted in mortality rate from 25-30%, While H9 single H9 AIV infection resulted in 10-15% mortality.

The situation may be aggravated if NDV infection was the complicating agent, resulting in mortality may 50%.

Simply many serotypes or genotypes of IBV may cause mild disease but IBV turns into a giant in the presence of complicating factors.

So,
- Other disease agents should be investigated, IBV infection may not be a primary pathogen.
- IBV present should be serotyped and genotyped to exclude the possibility of detecting vaccine strains.
- Monitor your flocks serologically for IBV, NDV, adeno, H5 H9 at processing age

- Modulate vaccination program according to lab. findings
- Treatment of E COLI infection according to antibiogram, as E-coli notoriously known resistant m.o. try using a combination of two antibiotics.
- Control Mycoplasma if suspected
- Monitor feed for mycotoxins, as they are immunosuppressive and or significantly hurt kidney and liver
- all in all-out system, reducing stocking density could be helpful.

Best Regards

Which IB isolated from affected flocks?
which complicated factor such viral infection AI H09 , ND or bacterial MG . e.coli? So you should send sample to monitor your flock by PCR, then you can design good vaccination program to control challenge according to lab result.

All-in all-out, biosecurity measures.

Dear Dr Aftab Anwar

Well said that in Pakistan, every year in wheat harvesting season, we are facing this problem duration is ‘’March, April, May and June’’. In my experience, this respiratory problem is not Infectious bronchitis outbreaks. It is rather related to environment pollution.

In a poultry house, with live birds, the average number of dust particles is generally below 100,000 particles/litre (1 mg/m3), although peaks of dust are always measured during feeding time or mating time when all the birds are very active.

Generally, fine dust particles above 10 µm are trapped in the upper respiratory tract and are cleared (coughed up) by the mucociliary apparatus. However, particles smaller than 5 um are able penetrate deeply and settle in lungs and air sacs.

During wheat harvesting/thrashing season, poultry farms located near thrashing activity, exceed the threshold level of 100,000 particles/litre. It is dust deposition that develops gasping (resembling IB clinically). Outcome would depend upon the amount of dust inhaled. Since dust is not cleared rapidly and signs may persist longer as per amount of dust inhaled. Unless dust is present, no antibiotic works.

One can try expectorant drugs as supportive therapy to clear dust.

Dear All

My opinion is kindly check the DOC against MG and MS specific on respiratory infection and use Tilmicosin (Poulmotil A/C) which is Elanco Brand and it is very helpful for respiratory infections and useful for respiratory vaccines like ND IB etc to cover all those types of infections you are facing in the field.

Distinguished Aftab Anwar.
First, try to decrease the microbiological load (mo) in the environment. I recommend using 2% iodine in water, sprinkled with a thick drop. This solution in addition to helping with the mo in the environment is an excellent fibrinolytic that will help the birds to control the production of mucus. I do not know the environmental temperatures of your country, so I ask you not to do this handling if high temperatures are reached along with high humidity.
Please, do not forget that to control the infectious bronchitis virus, vaccines prepared from strains homologous to the challenge strain should be used, since there is no cross-immunity between strains, so if they have already performed RT-PCR they should sequence to determine the field strain and from this carry out directed vaccination.
If you suspect that Newcastle disease is also involved, I recommend that you reinforce your vaccination schedule using live attenuated vaccines such as primovaccination and at least 2 vaccinations with emulsified vaccines as reinforcement.
If you control Mycoplasma with metaphylaxis you will also avoid complications with E. coli.

Sincere greetings.

Flocks of hens immunized with IB vaccine virus strains 4/91 MA5 and a much better protection against variant strains of IB virus. Vaccination is done in 1 and 14 days of living with live vaccines in 8 weeks is repeated with Ma 5 and in 16 is a dead - oil vaccine.
An infection with IB virus variant strains arise in laying hens and ovarian cysts oviduct(fallopian tube). I'm interested in whether a certain knowledge whether occurring cysts fallopian tube which is in operation (left) or a paraovarijalnim cysts rudimentary (right) fallopian tube?
Best Regards

As we know virus involved in this problem, so we should use any immunity booster.

Using organic acid from day-old chicks to end of flock reduce the bacterial load and help reducing secondary infection especially E.coli.

Optimum period between IB live vaccine and killed vaccine. What about your opinion to use IB PRIMER to control QX?

There are two schools of thought concerning IB immunization. One sustains the development of new vaccines as new variant strains appear. The main problem with this strategy is that there is evidence it may speed-up the emergence of new variants, a phenomenon clearly explained by Darwinian selection. The other one is the strategic use of antigenically distant vaccine strains which are already in use in order to immunize against a different field strain (Protectotype). This is not a matter of speculation but has been proved scientifically in several papers that have been published in international journals and forums, especially concerning the use of Nobilis IB Ma5 and Nobilis 4/91. This combination has recently received approval for its simultaneous application at the hatchery by spray. There is scientific evidence of this combination’s control of both Arkansas-related and QX-related field strains.

In relation to the two schools of thought and the Darwinian selection, I would like to make the following reflection:
if a challenge-homologous vaccine is used, which has the same genetic information, why would new variants be generated? And on the contrary, using a 4/91 vaccine with genetic information different from the challenge strain QX would not generate new antigenic variants?