Avian Preventive Medicine

Recommended books:1. Diseases of poultry, Calnek B.W. 1999. 10th edition2. Practical Avian Medicine, Hoefer, H.L. 1997.3. Poultry Diseases. Jorden F.T.W and Pattison, M. 2000, 5th edition4. Poultry Science and Medicine, Samad MA., 2013 2nd edition

Avian preventive medicine: It deals with the prevention and control of diseases in avian population.

How are the diseases causing economic losses in poultry industry?a) Low production performance (decrease production of eggs and hatchability, less

meat, slow growth rate, poor FCR, poor hatchability)b) Financial losses to farmers due to morbidity, mortality, low performance,

medication and decontaminationc) Human infection and death (zoonotic diseases like avian influenza, avian

salmonellosis)

Etiology of avian diseasesThe causative factors of disease may be classified as A) Agent (pathogens) B) Host and C) Environment. These three factors are usually works in combination; determine not only the disease which may range from a single case to epidemics but also the distribution of the flock.A) Agent factors

i) Biological agents: The biological agents may include Bacteria, Mycoplasma, Rickettsia, Chlamydia, Virus, Fungi and Parasites. These agents exhibit certain biological properties which include: a) Antigenic variation, b) Variation of virulence, c) Variation of immunological properties, d) Infectivity dose, e) Tropism, f) Survival within and outside of the host and g) Resistance/susceptibility to antimicrobials and disinfectants.

ii) Non-biological agents: a) nutritional agents, b) physical agents, c) chemical agents and d) mechanical agents

B) Host factors (intrinsic): a) age, b) gender c) immune status d) stress e) poor condition and f) no vaccination

C) Environmental factors (Extrinsic)i) Climate-a) Season, b) Ambient temperature, c) Humidityii) Air quality-a) Dust, b) Gases like NH3, CO2

and CH4 and c) Free radicalsiii) Housing-a) Direction, b) Ventilationiv) Management-a) Floor/Cage rearing, b) All-in /All–out, c) Multiple ages,

d) Vaccination and medication, e) Debeaking and sexing, f) Handling, g) Transportation, h) Hygiene and disinfection, i) Disposal of dead birds, litter and hatchery waste and j) Poor quality food and water

v) Nutrition-a) Deficiency or excess of nutrients, b) Water quality and supply, c) Feed toxins, d) Feed contaminants, e) Change of diet, f) Drugs (antimicrobials and growth promoter)

vi) Biologicals-a) insects b) rodents, c) wild animals, and d) opportunistic infectious agents

vii) Social-a) population density, b) sex ratio

Transmission of avian pathogensAvian pathogen exists because they are transmitted from infected to susceptible birds. The general source and types of transmission of pathogen

may also broadly group into two: A) Biological transmission and B) Mechanical transmission.A. Foreign imported sources

Airplane landing Vehicle entries Packing material like straw Imported live birds Vessel dockings Passenger luggage Meat or animal products

B. Infected birds Clinical infection Sub-clinical infection Carrier state Latent infection

The method through which pathogens are excreted from the body like excreta, dried skin epithelium, discharges from involved organ or parts, through eggs or blood sucking insects

After leaving or escaped from the body, the infection passes by means of water, soil, air, contact, vectors, mechanical and shipment.

1. Biological transmission

a) Transovarian transmission Egg borne diseases are transmitted from the infected dam to newly hatched

offspring of the fertile egg. Usually infectious agents hide inside the shell or membrane. From there it

can later invade the developing embryo and produce lesions, which are frequently observed in tissues or organ of offspring at hatching.

Transovarian transmission also occurs among pathogen readily transmitted by contact. Example includes Mycoplasma gallisepticum, M. synoviae, reovirus causing arthritis, pullorum disease, fowl typhoid, EDS etc.

Usually motile bacteria are transmitted in this way like Salmonellae and coliforms.

b) Mixed species of poultry One specially that is naturally resistant to a disease may act as a carrier of

that disease for another susceptible host Histomoniasis is chicken may cause great losses in turkey, if they run

together. So, turkey should not run on the yard where recently have had chicken.

Silent mycoplasma infection in chicken may spread to mycoplasmosis free turkey.

c) Multiple ages If multiple ages of chicken are reared on same premises, it has great

possibility to transmit pathogen from recovered carrier bird to healthy bird. Because susceptibility of diseases in birds is vary in different age groups.

d) Wild birds Wild birds are capable of carrying infection to domestic chickens or

turkey and free living birds may serve as a common source of infection

Avian influenza in a mild disease in waterfowl but cause serious loss in commercial chickens and turkeys.

e) VerminRodents are the common carrier of Salmonella typhimurium and S. enteritidis

f) Insects Many insects act as transmitter of disease and some are intermediate host

of blood or intestinal parasite. They also carry arboviruses Act as biological vector for protozoan disease like malaria, Haemoproteus

sp.g) Helminths and other invertebrates

Earthworm serve as transport hosts for the eggs of the cecal roundworm (Hetarakis gallinarum) which survive in tissues in an infective state in host tissues

Both cecal roundworm and earthworm play an important role in the transmission of Histamonas meleagridis

h) Humans Human constitute one of the greatest potential causes of introduction of

infection in poultry farm because of their mobility, duties, curiosity, ignorance, indifference, carelessness etc.

Zoonotic avian infections transmitted from avian species include Newcastle disease, avian influenza, salmonellosis, tuberculosis, the encephalitides, chlamydiosis and erysipelas

i) Backyard and pet fowl Poultry kept as pet or backyard farming are potential sources of infection

in commercial poultry farm Poultry farm and hatchery owners and workers should be especially

cautious about contact with imported pet birds or migratory waterfowl because they might be symptomless carrier of diseases that are highly virulent for domestic poultry

j) Live bird markets The live bird market trade has been strongly associated with the

propagation and spread of different avian disease e.g. Avian influenza, inflectious laryngotracheititis

Farm manager and owner should keep such buyers and their equipments out of their farms and offices

k) Recovered carriers Carrier birds are those that have apparently recovered from a clinical

infection but stll retain the infectous organism in some parts of the body Recovered seems to be healthy, but organism still multiply in the body

and release in the environment and act as carrier for healthy bird.l) Other mammals

Scarcosporidia and Toxoplasma occur more frequently in wild birds, particularly in duck than commercial chickens

Birds species are infected following consumption of mammalian feces or by flies or earthworms, which act as transport hosts.

2. Mechanical transmissiona) Humans

Human are the important factor in the transmission of infectious agents of poultry in the context of modern commercial poultry operations

Transmission may be attributed by owner’s, neighbours, caretakers, servicemen, work crews, feed-truck drivers, repairmen and visitors who are indifferent and careless to follow the acceptable decontamination procedures.

Managers are indirectly responsible for transmission of infection due to mixing sources of infection or introducing inadequately cleaned equipments.

b) Insects Biting insect may transmit diseases mechanically Mosquitoes transmit fowl pox virus and fowl ticks may transmit

Pasteurella sp.c) Feed

Feeds are major source of paratyphoid organsism (Salmonella paratyphi)

Feed ingradients from animal origin are the major source of Salmonella infection

Contamination of feed in warehouse by infected feral pigeons increase the outbreak of paramyxovirus 1 infection

d) Hatchery contamination Improperly cleaned and disinfected setter trays and incubators can be

the source of bacteria that may result in egg contamination or omphalitis in newly hatched chicks and poults

Incubator, ventilator and air conditioning modules may become infected with Aspergillus spores in chicks and poults and causing subsequent mycotic air saculitis and pneumonia

e) Houses and equipments The environment of poultry house becomes contaminated with a

pathogen, resulting in rapid intraflock transmission The equipments and vehicles should be washed properly with

disinfectant solution before use in another farm area Workers and other equipments must be thoroughly disinfected before

being brought into contact with flocksf) Vaccination

Poultry vaccines produced in the commercial laboratory are generally tested for the presence of avian pathogens

The vaccine personnel and equipments usually carry pathogens which are harmful for commercial flocks

Equipment used to vaccinate against Marek’s disease or DOC can transmit infectious agents unless needles are changed frequently according to manufacturer’s instructions.

g) Dead birds Carcasses are the important source of disease agent and transmit

disease to healthy flocks Carrion eating vermin transmit pathogens in the farm Birds may be infected by cannibalizing carcasses

h) Airborne transmission Aerosols are the common source for harmful avian pathogens like ND,

infectious bronchitis and infectious laryngotracheitis It is also likely that transmission occurs between adjacent houses It has been recorded that airborne transmission of ND over distance of 5

miles.

Methods of disease dissemination in poultry

Disease may be transmitted from one individual to another in the same flock, from one flock to another, from one place to another and from parent to offspring.

1) Infectious agent escape from the body of an infected individual by /in Excreta Dried skin epithelium Discharges from involved organs or parts Through egg Blood sucking insects-mosquitoes in avian pox

II) After leaving or escaped from the body, the infection passes on Water Soil Air Contact Vectors Mechanical means By means of shipment of infected birds to susceptible birds from one place to

another

Transmission of infectious agent may be either i) Horizontal transmission or ii) Vertical transmission

a) Horizontal transmission: Transmitted directly or indirectly from infected birds to susceptible birds.i) Hatchery transmission (specially air borne): Large number of chicks might be

affected due high humidity, high air flow e.g. aspergillosis, salmonellosisiii) Air borne transmission: e.g. candidiasis, salmonellosis, aspergillosis etc.iv) Mechanical and vector-borne transmission: Human, equipment, free-flying

birds, predators, rodents, insects etc.v) Environmental transmission: Contaminated uncleaned poultry house and

litter e.g. Marek’s disease vi) Recovered carrier birds: avian mycoplasmosis, infectious laryngotracheitis,

hemophilus infection etc.b) Vertical transmission: Transmitted from one generation to next usually from the hen

to the newborn chicks through eggs (embryonic) infection. True vertical transmission: Ovarian or uterine infection e.g. pullorum, avian

encephalomyelitis, avian mycoplasmosis Apparent vertical transmission: Fecal contamination of egg with subsequent

penetration e.g. paratyphoid infection and Escherichia coli

How will you prevent egg borne diseases in poultry farm?The methods of prevention of egg transmitted diseases are: a) Removal of carrier birds which are the persistence source of infection, b) Egg washing at higher temperature than egg, c) Egg dipping (mainly for mycoplasma) in tylosin at lower temp than egg, d) Egg fumigation, particularly to get rid of bacteria and fungi, e) Frequent collection of eggs (3 to 7 times a day, treatment of litter in nest box) and g) Hatchery hygiene.

Methods of egg washing, rinsing and sanitizing The hatching eggs must be carefully washed, rinsed and sanitized prior to

antibiotic treatment The egg washing disinfectant solution should contain bleach (sodium

hypochlorite) @ 1 tsf/gallon water at temperature between 110-1200F and immersion time should not exceed 3 minutes

Eggs are pre-warmed at 1000F for 3 to 4 hours and immediately submered into antibiotic solution. The antibiotic solution should contain either gentamicin (1 g/2

Litre water)or tylosin (1g/L water) and left the eggs in the antibiotic solution for 15 minutes and finally place the dry eggs into the incubator

Methods of fumigation Requirements of hatching egg fumigation: 1.35 ml of 40% formalin solution

plus 0.84 g potassium permangate (KMnO4) or 1.2 ml of 40% formalin plus 0.6 g KMnO4 /ft3 air space. Empty incubator and hatcheries may be fumigated using double this concentration

Procedure: Mix both the ingredients in an earthen-ware or heat resistant container having at least 10 times the capacity of the ingredients being added. Circulate the gas for 20 minutes at 700F or higher. Equipments without eggs can be allowed to fumigate overnight before exhausting the formaldehyde gas

Precaution: Formalin or formaldehyde gas is carcinogenic and irritant to conjunctiva and mucous membrane and potassium permanganate is also poisonous to human body.

Microbial control in poultry facilities Sterilization: The destruction of all infective and reproductive forms of all

microorganisms. Disinfection: The destruction of all vegetative forms of microorganisms but

spores are not destroyed Sanitation: The destruction of pathogenic organisms number to a level at which

they do not pose a disease threat to their host Disinfectants: Disinfectants are chemicals used mainly on inanimate objects to

destroy or inhibit the growth of microorganisms Antiseptics: Antiseptics are anti microbial substances that are applied to living

tissue/skin to reduce the possibility of infection, sepsis or putrefaction. An antiseptic is a germicide applied to living tissues but a disinfectant is a germicide applied to inanimate objects.

Disinfectants: Agents which are too toxic to apply to the body but useful in destroying pathogens, contaminating inanimate objects-buildings, feeding and cooking utensils, surgical instruments.

Disinfectants are chemical agents that can kill pathogen on contact. So, cleaning prior to disinfection application is essential.

Selection of ideal disinfectantsThe lethal action of disinfectants for various pathogens depends on the chemical composition of the disinfectant and make up the organism. Although many disinfectants are readily available but not all disinfectants are effective against all organisms.

Characteristics for selection of disinfectants Cost Efficacy Activity with organic matter Residual activity Activity with soap Toxicity (relative safety to birds) Effect on fabric and metals Contact time Temperature Solubility (acidity, alkalinity pH)

Consideration to yield the best results from a disinfectant

Cleaning before the application of the disinfectant is essential. All disinfectants are less effective in the presence organic material containing surfaces, so dirt should not be disinfected directly. Organic material interferes with the action of disinfectants by: a) Coating the pathogen and preventing contact with disinfectants, b) Forming chemical bond with disinfectant, thereby making it inactive against pathogenic organisms, c) Reacting chemically with and neutralizing disinfectants. So, clean and disinfectant in separate operation is considered.

Disinfectant solutions are more effective when applied with lukewarm water (neither hot nor cold) solutions. Hot solution can reduce disinfectant efficiency

Most of the disinfectants are not effective instantaneously and they require a certain contact time (usually 30 minutes) to be effective

Embryos are very sensitive to disinfectants. So, using disinfectants are contraindicated whose already have remain embryo.

Allow all surfaces to dry thoroughly before reuse. Dryness reduces reproduction, spread and transport of germ.

Improper use of disinfectants can damage or hinder the function of equipments. Some disinfectants are corrosive or clog spray nozzles water systems

Always follow label of manufacturer instruction before use

Disinfectants used in poultry industryDisinfectant can be divided into the following classes based on their chemical composition and characteristics.

1. Alcohols (Isopropyl or Ethyl alcohol) Wide germicidal activity, non-corrosive but poses a fire hazard Limited residual activity due to evaporation Alcohols provide limited activity in the presence of organic matter Excellent for disinfecting surgical instruments or other small objects Not considered against bacterial or fungal spore To expensive for general use Usually used as a 70 to 95% concentration

2. Halogenes (Iodide or Hypochlorides) Provide wide germicidal activity but are corrosive Limited activity in presence of organic matter Poor residual activity, low toxicity but may stain surfaces Effective at low concentration for disinfecting clean small objects Lost cost but requires frequent application It can be used in water system and foot bath

3. Quaternary ammonium compounds (e.g. Benzalkonin chloride) Odorless, colorless, non-irritating, non-corrosive and deodorizing Limited germicidal activity Not sporocidal, effective against vegetative bacteria, fungi and viruses Limited effectiveness in soaps, detergents and hard water salts Reduced efficiency in the presence of organic matter Low cost Used in commercial hatchery, incubator equipments

Safe for hatching egg Leaves residual protection of eggs Safe for equipments and personnel involve in hatchery

management Compatible with antibiotic dipping of eggs

Application of quaternary ammonium compound: a) 10% quaternary ammonium disinfectant b) 0.4% EDTA and c) 4.2% Sodium carbonate (make the solution up to pH of 8.0 ).

4) Phenol (carbolic acid) Wide germicidal range , not sporocidal Corrosive, irritating and good residual activity Hatchery , equipments disinfectants and footbaths Turn milky in water Very effective in presence of organic matter House disinfectant

5) Coal tar derivatives (cresol) Wide germicidal , but not sporocidal Corrosive and toxic in high concentration Highly efficient in presence of organic matter Moderately expensive Not well suited for near egg and chicks due to noxious gases

6) Aldehydes (Glutaraldehyde) Widely germicidal, sporocidal and fungicidal It can be used as fumigating eggs and incubator Slight or moderate efficacy in presence of organic matter Moderate toxic and cost

7) Oxidizing agents (Hydrogen peroxide, potassium permanganate) More valuable as a cleanser and deodorizing agent Ineffective in presence of organic matter Small utensils, commercial poultry operations Moderate cost

8) Iodophors (Iodine) In hatcheries, iodine is used on equipment, wall and water disinfection Least toxic disinfectants Can stain cloth and porous surface Not effective in presence of organic matter

Procedure of disinfection of poultry premisesA. First clean

Remove all bedding, feed and manure Sweep out loose dirt, cobwebs etc Scrub all surfaces with disinfectant Rinse all detergent and organic matter from surfaces

B. Next, disinfect Apply the disinfectant Allow the disinfectant to dry Reapply the disinfectant and allow to dry a second time (optional) Clean and rinse the disinfectant Dry all water and feeding equipments before refilling them

Disinfection of drinking water by chlorination Chlorination is commonly used as disinfectant for drinking water at a

concentration 3ppm It can be tolerated up to 10 ppm in chicken

Tips on chlorination Organic matter quickly inactivates chlorine. So, at first clean water then adding

fresh chlorine solution

The pH of water should be below 8.5 and ideal pH for effective chlorination is 6.0-8.0

Stop chlorination two days prior to any vaccination with live vaccines or bacterial vaccines via drinking water

Recommended chlorination does not alter nutritional chlorine intake Keep away chlorine solution from metal

Poultry disease control strategiesPrevention, control and eradication are the three terms used most commonly in association with disease control activities.

Prevention: Those measures intended to interfere an attack or occurrence of a disease. Examples, quarantine and vaccination. It can be applied at either individual bird or a flock

Control: To reduce the both prevalence (of existing infections) and the incidence (of new infection), as well as morbidity and mortality rate from clinical diseases

Eradication: Eradication is the method for complete elimination of the causative agents. It is usually done by treatment or by removal or disposal of the infected animals.

Poultry disease prevention and control

Disease control involves all the measures designed to prevent or reduce the infection and consequences of the disease. It includes; a) Controlling the reservoir and source of infection, b) Breaking transmission routes and c) Manipulating the susceptible host (birds at risk).

a) Controlling the reservoirs and source of infection Early identification of reservoir or source of infection Proper treatment of affected birds Epidemiological investigation to reduce the infection load Isolation of infected birds from healthy birds Serological testing and removal of carriers Hygienic disposal of dead birds, litter and hatchery waste Feed and water quality control Through cleaning, washing and disinfection of farm houses and equipments Hygienic hatching of chicks

b) Breaking transmission routes Human traffic control such as locking the doors and banning the visitors Providing foot and wheel bath at the entrance of houses All-in/ All-out farm management Pest control (flies, mosquitoes, ants, rodents, litter beetles, lice , mites etc) Personnel hygiene Restriction of movement of personnel, feed, vehicles and farm equipment Avoiding of on farm trading

c) Manipulating the susceptible host (birds at risk) Genetic improvement of disease resistance by conventional selection and

genetic engineering Manipulation of immune system by:

Vaccination Providing good quality well balanced feed Avoiding social, environmental and managerial stress Providing good quality well balanced feed Immunomodulation

BiosecurityThe term Biosecurity is derived from Greek word bio refers to ‘life’ and security implies some sort of protection. Hence, Biosecurity refers to a program that is designed to protect life. Biosecurity is a set of management practices which prevent the potential for the introduction and spread of disease causing organisms onto and between sites (flocks). In means to maintain poultry secure and free of germs.Biosecurity has two components a) Bio-exclusion to preclude the introduction of diseases to the farm, b) Bio-containment to prevent the spread of disease within the farm and to other farms.Factors influencing BiosecurityInfection may be harbored and spread in a variety of ways. In relation of poultry, these may include

a) Diseases concern Most of the diseases are viral origin such as avian influenza, Newcastle

disease, IBD and othersb) Possible route of transmission : Direct contact and mechanical routes through

fomites are considered to be the important routes of transmission of diseases1. Poultry birds

Replacement of birds from sources of lower biosecurity standards Transfer of birds from farm to farm Infected birds that shed organisms without showing clinical signs Improper disposal of dead birds

2. Possible disease reservoirs Wild birds and waterfowls Feral and domestic animals and pets Insects-fly, beetles, cockroaches Domestic birds-free range village poultry Rodents-rats , mice

3. People Workers and visitors that move in and out of the farm especially those

that move from farm to farm People can also serve as a mechanical vector for disease transmission

i.e. hands, boots, hair and clothing4. Equipment

Introduction of potentially contaminated equipment into the farm5. Vehicle

Farm related vehicles enter in the farm without disinfection6. Manure

Improper disposal of used litter from suspected and infected farm Use of poultry manure from other farms

7. Feed supply Feed supply and delivery from unknown factory Recycling of used feed bags Shared feed between farms

8. Air borne Transmission through air borne or dust dispersion

9. Water borne Surface water attracts wild bird and water fowl Contaminated water supply Temporary rain water flow from infected farm to other farms

Table 1. Tips for disease prevention

S/N Things to do Rationale for doing them

01 Regular sanitation through cleaning, scrubbing and disinfection of the poultry house is very important

It will prevent the growth bacteria, viruses and parasites and also deters unwanted rodents

02 Proper disposal of old litter before introducing new chick in the farm

Exposing birds to old litter is not recommended as the litter may acts as source of infection of disease agents and transmit infection to new flock

03 Do not permit the visitors in poultry farm if they have had contact or visited other poultry farm

Visitors can transmit diseases through their clothing, shoes and unwashed hands.

04 Quarantine new birds from outside flock for 14 days

A 2-weeks quarantine is necessary to monitor for any diseases and a longer period may be necessary to treat the diseases

05 Prevent other wild birds from contacting flock birds

These free-living birds can carry diseases and parasites to the chicken

06 Purchased feed from a reliable source and do not feed moldy feed

For health and productivity, birds require a nutritionally balanced feed.

07 Vaccinations are important in disease prevention

Chicks and pullets should be vaccinated as they develop antibodies against common poultry diseases

08 Provide a well ventilated chicken house This reduces to build up ammonia, stress and pen-mate fighting

09 Properly dispose of all dead birds Prevent flies and odor and reduces potential transmission of disease

10 Separate sick chicken from the rest of the flock

Diseases can be spread through direct contact with infected birds

11 Get an accurate diagnosis of disease as soon as possible

Some disease show similar clinical signs, although proper treatment may differ

12 Extreme care must be taken during rearing of pet birds

Pet birds, like parrots can pose a serious threat to chicken because they can harbor of many devastating diseases of chicken.

Types of Biosecurity practices in poultry farm

There are four types of Biosecurity on the basis of measures and activity which include a) Conceptual and structural b) Regulation concerning movement c) Traffic control and d) Operational biosecuritya) Conceptual and structural biosecurity: The conceptual biosecurity involves

the site planning and location of farm house, and the structural biosecurity involves the design of the farm and buildings

The poultry farm should be constructed away from the locality and residential premises

The poultry shed should be constructed in an east-west direction to avoid direct sunlight and provide good concrete floor easy and proper cleaning

Proper distance between breeder, grower and commercial farm should be maintained properly.

Breeder farm should be sited at least five miles away from commercial farms

A boundary wall with a security gate should be constructed and a strong barrier over the boundary wall should be provided

There must have a well drainage system and electricity in the farm

Rooms for each operation should be constructed separately and there should be space for an office, rooms for the traffic, vehicle, storage and also bathroom and changing room at the entrance of the shed

Communication pathway between rearing shed to another shed should be properly maintained

The proper measures of ventilation should be adopted and wire-net should be provided in the ventilator to restrict any wild bird

All poultry house should be designed and maintained so as to prevent the entry of wild birds and limit the access of rodents as per as practical

The proper feeding and watering system should be provided to prevent fungal infection

Hanging a sign board in front of the farm indicating that ‘’Restricted Biosecurity Areas, No Entry Unless Authorized”

Parking area for vehicles should be restricted in farm site. It is best to park vehicles at least 100 ft away from poultry house

All connecting road within the farm should be provided with facilities like cleaning, washing of vehicles and foot wears to prevent the spread of pathogen

Foot baths containing suitable disinfectant agents should be used at all shed doorways

No other avian species should be reared on the farm like ducks, geese, pet birds, other aviary birds etc.

b) Regulation concerning movement New birds represent a great risk to biosecurity because their

unknown disease status Importation of birds and their products must be controlled by

regulation of Veterinary services Isolation of all sick and quarantine all new in-coming stock from

the resident populationIsolation

Isolation is the separation of sick patient with a specific infectious disease from those who are apparently healthy

Isolation refers to the confinement of animals and birds within a controlled environment

Isolation also applies to the practice of separating birds by age group. In large poultry operation , all-in and all-out management system allow simultaneously between flock and allow time for periodic clean-up and disinfection to break the cycle of disease

Quarantine: Quarantine is used to separate and restrict the movement of healthy birds or animals who may have been exposed to communicable diseases to see if they become ill.

Newly arrived bird should be separated from old flock. This allow screening for disease as well as special monitoring of general demeanor , behavior and feeding

Length of the quarantine appropriate for incoming birds will vary depending on the species, pre patent and incubation period of the suspected diseases. A quarantine period may be 14 days, 60 days, six weeks or three weeks have been recommended.

A full physical examination should be carried out at the beginning of the quarantine period, including hematological and biochemical examination.

A full physical examination also carried out at the end of the quarantine period

Fecal sample should be screened repeatedly during quarantine for salmonella and parasitic infections

It is important to ensure the complete necropsy examination of birds which dies during quarantine and to keep detail records of reference

Sick or injured bird should be isolated from the cage mates Quarantine and isolation should be kept quiet and disturbances

free as much as possible.c) Traffic control

Peoples are the most important animate factor including employees, servicemen, lorry driver, vaccination crews and veterinarian

Employees living on a poultry farm should work at that farm and employees should not personally own the poultry or pet birds

Employees should not visit the location where birds or swine are present Employees should always take shower and put on clean clothing before

going to work Farm personnel must be provided and documented the training in on-farm

biosecurity All visitors must follow the biosecurity procedures Use regularly refilled foot dips with suitable disinfectant The vehicles which enter in the farm must be spraying wheels or wheel

arches with disinfectants Direct the flow of on-farm traffic from the youngest to the oldest birds Washing hands properly after handling of birds

d) Operational biosecurity Operational biosecurity means day to day routine practices in the poultry farms to

prevent the diseases. In includes management and routine procedure intended to prevent and spread of infection within the farm premises.

The diseases and pathogens can spread to the poultry shed from different sources like hatchery, poultry feed, water, equipment, rodents, insects, wild birds, people, vehicle and others. The following measures should be considered as operational biosecurity include: 1) Hygiene, sanitation and disinfection 2) Vaccination 3) Medication 4) Parasitic control 5) Good nutrition and 6) Good environment

1) Hygiene, sanitation and disinfection: The following key points should be considered for sanitation

Stage 1: Removal of gross waste, cleaning and dry Remove stock Remove gross organic waste Remove dust

Stage 2: Hygiene and sanitation Reduce infective material Use a detergent/ sanitizer Allow to dry after words

Stage 3: Water systems Drainable-drain, clean , disinfect, flush Non-drainable-clean, sanitize

Stage 4: Removal of waste from equipment Scrub/pressure wash Detergent sanitizer Disinfectant and dry

Stage 5: Disinfection Remove residual challenge

Use broad spectrum disinfectant Cover all surfaces Cover all cracks and crevices Allow to dry

Stage 6: Aerial disinfection Covers inaccessible areas Replace movable equipment first, then spread bedding material Fumigate-safety required with formaldehyde Rest period

Stage 7: Routine procedures Control/restriction of visitors Strict use of protective clothing Hand washing Foot-dips

II) Prevention by vaccination: Poultry have a good immune response too many diseases and to vaccination. They also pass immunity to offspring through the egg. Threrefore, breeders require a special vaccination program. Ensuring that the vaccines are properly admininstered at the proper time, utilizing the antigen combinations to provide the titer needed to resist the challenge. Determining the types of vaccines to be used, the route, the age and the method of administration should be discussed and consulted with expert prior to vaccination.III) Prevention by medicationIV) Good nutrition: Nutrition plays an important role in the health of poultry flock and it has ability to enhance resistant to non-specific diseases. Good nutritional prevents infection by a number of mechanisms, notably through vigorizing the immune system, maintaining the integrity of epithelial tissue and other vital organs of the body.V) Good environment:

Unhygienic environment increase the incidence of various infectious diseases like salmonellosis, colibacillosis, coccidiosis etc.

Unsuitable ventilation conditions with high incidence of ascites and CRD complex

Types of vaccine There are two types of vaccine viz. A) Traditional vaccines and B) Innovative vaccines

A) Traditional vaccinesI) Live vaccine: a) Fully virulent- Eimeria in chicken CoccivacR b) Attenuated

vaccine-Duck plague virus vaccine, Duck viral hepatitis vaccine , naturally occurring mild strains of virus-H120 strain of IBV, B1strain of NDV c) Antigenically related organisms-Herpes virus of turkey to protect chicken from Marek’s disease, live pigeon pox vaccine to protect chicken for Fowl pox

II) Inactivated vaccine: Bacteria –bacterin, Toxin-toxoid, killed oil adjuvant vaccine- Fowl cholera vaccine, Egg drop syndrome

B) Innovative vaccines: Congugate vaccine , Sub-unit vaccine, recombinant vaccine, DNA vaccine-genitically attenuated vaccine, synthetic peptide vaccine

Advantages and limitations of of vaccine

S/N Parameters Live vaccines Inactivated vaccine1 Preparation Attenuated, avirulent or fully Killed organisms or toxoid

virulent2 Safety Some risks due to reversion of

virulenceUsually safe

3 Stability Affected by temperature and sunlight, short shelf life

Stable on storage

4 Duration of immunity Strong and long lasting immunity, 1 or more than 1 year

Usually 1 month

5 Onset of immunity Rapid Slow6 Antibody response IgM, IgG and IgA Predominant IgG7 CMI resposne Good Poor8 Locally secretory

immunityUsually present Absent

9 Route of adminstration Effectively by natural route or injection

Injection

10 Antigenic dose Low High11 Number of dose

required Usually single Multiple (boosters needed)

12 Adjuvant requird Not required Required13 Influence of MDA

(maternal derived antibodies)

Very significant (adverse effect) Minimal effect

14 Cost Low High

Vaccine productsVaccines are produced mainly in three forms: i) Liquid vaccine, ii) Freeze dried vaccine and iii) Dust vaccine

1) Liquid vaccine-It is in fluid form ready to use2) Freeze-dried vaccine-The vaccine is stored as on pack of freeze dried material

and one pack of diluents, often a sterile saline solution. They have to be mixed before use

3) Dust vaccine-Where vaccine is prepared for administration in the dry formMethods of vaccine administrationA wide range of methods of administration of poultry vaccine is available for use in the hatchery or on farms

Methods of administration of vaccine 1) Individual administration: In vivo-injection (hatchery, subcutaneous

injection, intramuscular injection, wing web puncture, feather follicle, eye drop, nasal drop

2) Mass administration: Coarse spray, drinking water, aerosol, on-feed spray

Factors that may contribute to vaccine failure1. Host related factor

Presence of maternal derived antibody in case of live vaccine Animal incubating the disease Immunosuppression Age, nutrition, poor management and housing with resultant heavy challenge

of infectious agent2. Vaccine-related factor

Unsatisfactory vaccine: incapable of stimulating protective immunity because of composition or strain (serotype)

Vaccine past expiry date Inadequate passage vaccine and consequently still virulent for some

susceptible species

Loss of potency of vaccine: Inactivation of live vaccine due to sunlight, improper storage or contamination of multi-dose container.

3. Other factors Inactivation of vaccine: Administered by scarification and loss of potency due to

topically applied disinfectant (alcohol)Administered by wrong routeVaccine (lyophilized) reconstituted with inappropriate diluents such as water

contained chlorineSusceptible agent in vaccine affected by a drug administered to host animal-

irradiated larval vaccine, anthelmintic, antibiotics etc.

Probiotics in poultry

ProbiotcsThe word probiotics comes from Greek word means ‘for life’ is opposite of the antibiotic. Probiotic is a live microbial feed supplement which benefits the digestive tract by improving its gastrointestinal balance.The term probiotic was first introduced by Lilly and Stillwell to describe growth promoting factors produced by microorganisms.Probiotics microbes are Lactic acid bacteria (Lactobacillus, Strept) and Bifido bacteria (Bacillus, Yeast).

Inhibit the growth of potentially pathogenic microbes by lowering the pH through production of lactate, lactic acid and fatty acid.

Status of normal gut microflora1. Digestive system: Contain 400 species of micro-organism of microflora.2. Essential benefits of microflora to the hosts

Helps in digestion Aids in the synthesis and absorption of vitamin and minerals Reduction of pathogenic bacteria and their toxic components Breakdown cellulose and other polysaccharides Stimulate the immune system Reduce sub-clinical infections

Characteristic of a good probiotics Safety: non pathogenic and non toxic Anti E. coli and salmonella activity Optimal responses in a specified dose range Viable cells present in numbers those provide 107 to 108 CFU per bird Stable for long period under normal storage conditions Viability in the gut: Capacity to survive and metabolize in the gut. e.g. resistant to

HCl, organic acids and bile.

Causes of disturbances of normal gut microflora Gastro-enteric disease Antibiotic therapy Nutritional changes or adequacies Poor quality food and water-bacteria, mycotoxin contamination High stocking rate : Excessive bacterial challenge Vaccine causes immunological or irritant stress Inadequate ventilation Sudden environmental fluctuations and air borne challenge

Poor quality litter Stress: modern animal management

Stress stimulates pituitary gland and release ACTH hormone, which acts on adrenal cortex and produce cortisol and incrase intestinal pH. Alteration of intestinal microflora due to incrase pH in the intestine.Mode of action of probiotics

Maintaining normal intestinal microflora by competitive exclusion and antagonism

Altering metabolism by increasing digestive enzyme activity, decrease bacterial enzyme activity and ammonia production.

Improving feed intake and digestionOther effects of probiotics: Neutralizing enterotoxin and stimulating immune

system.