The Art and Science of Diagnosis of Poultry Diseases

Published on: 04/28/2021
Author/s : Dr. Tahseen A. Aziz / Avian pathologist and Diagnostician, Rollins Animal Disease Diagnosis Laboratory, North Carolina Department of Agriculture and Consumer Services, Raleigh, North Carolina, USA.

The definition of disease in the broad context is any deviation from the normal state of health. Diseases can be divided into two broad categories: Infectious and noninfectious. Infectious diseases include those caused mainly by bacteria, viruses, mycoplasmas, fungi, and parasites. Non-infectious diseases can be further divided into three categories: management-related diseases, toxicities, and nu...

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April 28, 2021

Excellent summary, Dr. Aziz. Would you be able to expand on what do you think would be the role(s) of NGS, or more specifically, of random metagenomics analysis on avian disease diagnostics?

Nimer Natsheh Nimer Natsheh
Veterinary Doctor
April 29, 2021
it is an excellent information for field vet.
Zahed Abbasi Zahed Abbasi
April 29, 2021

It is an excellent and short review of diseases diagnosis and you explained it as an expert clinician. In my experiment some diseases are strongly management dependent for example a wrong light program in a layer flock can cause a before peak collapse or post peak dip, and it can be defined as an infectious disease like IB or ND. understanding the real cause needs a long time and good knowledge about poultry biology and light.
I mean it is a complex process to diagnose interference of management and infectious agents and to prevention first needs to correct management item or distinguish them from infectious agent.
Managing poultry diseases needs an expert veterinary practitioner to a jigsaw puzzle.
Thanks so much for your good explanation.

May 3, 2021

I compliment the author for good analysis, diseases have negative impact on the performance of poultry flocks, the pathologist should have holistic approach in differential diagnosis of poultry health problems.
The definite etiological agents such as Bacteria, Virus, Fungi, and Parasitic infections are well known, but the diagnosis of problems arise from managemental, nutritional and other non infectious causes require skill. I give a classic example of occurrence of coccidiosis in some batches of chicken of same age and same feed. It was a big task to diagnosis. we need to apply our mind here. I visited their feed mill in which they were manufacturing feed on two shifts -day and night. When we analyzed the feed manufactured on night there was outbreaks rather than day time manufacturing feed. This is because of frequent power failure in night time and improper mixing of coccidiostats in the feed. Here we need common sense in diagnosis of such problem. Therefore, the diagnostician should have a holistic approach.

May 4, 2021

Nice write up in my country u hardly get the service of a qualify vet doctor and mostly we have the problem of fake drugs

June 6, 2021
Raphael longkat Please where is your country?If it is closer to Nigeria we can ship qualified vet doctor we can supervise. Dr Charles Ibe DVM FCVSN
May 11, 2021
I want to know this thing that what are the ways to diagnose coccidiosis in poultry?

Can anyone send me the link of a recent publication about the methods to diagnose coccidiosis in chickens eapecially including both traditional and molecular methods.
June 6, 2021
•Amproleum is the most common treatment for Coccidia. Amproleum 25% is available. Add 0.6gms to 1.0gms per liter of water.
•3 to 5 days treatment is enough
•Sulpha Quinoxaline is effective.
•When coccidiocidal drugs are given for prevention, they should be withdrawn by 16 weeks.
•The spores of coccidia remain in litter for long time ie even when birds are not there. The birds once exposed get immune to disease for life. Coccidiostats allow the germs to develop to some extent so that the birds develop resistance.
•High humidity and wet litter make the spores to germinate and multiply in the epithelial cells.
•Many coccodiostats like DOT, Maduramycin,Esb3 and Salinomycin are added in feed on regular basis to prevent the disease.
•Vaccines are also developed. The killed vaccines are given to parent stock. Live vaccines are given to baby chicks at hatchery or within three days.
•More prevalent in deep litter because the birds pick up the spores from litter. Generally not a problem in cages.
June 2, 2021

Diagnosing poultry diseases can be an art. With closed housing systems with strict biosecurity protocols, the visit of the owner and a vet became need-based. Spotting a problem is based on the data collected. On the contrary, the poultry house attendant spends more time with the birds. A dedicated attendant can spot the disease much earlier than the owner or the vet.

Many poultry diseases/problems are age-specific. In most of the medium and large operations gave separate brooding growing and laying operations in different houses or different premises. Poultry attendants should be allocated with one house for a long time. his observation is more crucial and faster than the owner or the vet.

Taking the example of I.B.D (Gumboro), the disease strikes mostly between 21 and 28 days. A keen attendant can spot sick birds during that age. His prompt reporting is more crucial than the post mortem and laboratory diagnosis.

Coccidiosis is seen more on deep litter and rare in cages. The disease is mostly seen after 4 weeks and before 16 weeks. observing dull birds off fed and bloody droppings is faster than post mortem or the lab.

Water shortage and feeding delays cause much more damage in layer flocks by way of production drops than disease many a times. An alert attendant can diagnose and prevent the problem. Observation on the place of of dead birds in a house pecking are spotted first by the house attendant much earlier.

If the house attendant does not pay attention and misleads the owner and the vet, the diagnosis in poultry can remain a mystery.

June 7, 2021
drkotaiah indbro Thank you so much, sir.
June 8, 2021

drkotaiah indbro
Thank you so much for this information.

June 17, 2021
drkotaiah indbro Thank you, very short and direct to the point
August 6, 2021
Dr Kotaiah Talapaneni, thanks
June 5, 2021
Dear Dr Kotayya
you are exactly right when you say the importance of poultry attendant is crucial even to prevent and early diagnosis impending problem in a shed or farm . In order to achieve this a well trained ,committed husbandry known person is need of the hour in developing countries where biosecurity and immunology has to be further updated
Zahed Abbasi Zahed Abbasi
June 6, 2021
Hi to all:
Disease diagnosis is based on taken of flock history as one aspect like feed and water consumption - daily mortality - respiratory sound ,fecal consistency change in birds behavior and house climate and so on in one and attendant is a good source for taken it .in every house and flock visit , a good clinician must be able to hear attendant .
But only an expert practitioner can discover the relation between managemental and house condition and diseases that affect the flock health and performance .
Surinder Khanna Surinder Khanna
June 9, 2021

I agree with dr iqbal for non pathological reasons

Any disturbance due to handling ,shifting ,,vaccinaruon change of labour earth quake , predators drop prodn for few days which may range 5 to 10 pc. Nutrional reasons like poor vit premix accidental missing of salt vitamins etc lead to drop in prodn mesh size of feed particles marble particles also cause drops change in new ingredient also lead to drop sudden drop in bodyv wt of birds due to climatic changes or negative energy cause drops high moisure maize may cause drop.
Non stirring of feed in feeders improper uniformity of birds.
in all such cases only expert management professional can analyse with help of farm supervisor.

Surinder Khanna Surinder Khanna
June 9, 2021
Dear dr Abbasi
I apologised for wrongly writing your name .On the aforesaid topic I may further mention that our supervisors need to be skilled as they should regularly measure wt of sample eggs with relation to wt of birds .
1 to 5 pc birds remain in flock with untrimmed beak any time which leads to pecking problem in total flock and becomes vice .such problem is solved at grass root level ...Any increase or culling of birds is related with water problem or virus in incubation which needs to be detected early .
Many breeds have poor metabolism of toxins causing pasty vent leading to pecking .such problems are diagnosed by supervisor level
June 9, 2021
Dear All, Good & Safe day
Very healthy discussion, I Wanna minute addition to Respected Mr. Surindar Khanna,
Sir, Not only an expert eye for health search, There are so many other parameters to monitor and rectify immediately especially in Modern Houses, so well trained team with mechanical expertise required to visit in as routine, lots of issues will need to handle during Growing,
And practically all are available and doing their job by entering in, so
the point is Y only an Expert ( Vet) and Owner Visit is critical to the bird's health.
We are providing proper PPE and Hygienic protocol to overcome any issue directly with an expert eye.
July 30, 2021
Thank you very much
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