The disease of Newcastle , also called “pseudopeste avian”, “pneumoencéphalite avian” or “disease of Ranikhet”, is a Zoonose Oiseau X, due to a Virus.
La Morbidity and the Mortalité strongly vary depending on the virulence of the stock, the immunity and the state of the animal and other environmental factors.
Under the generic name of “ plague aviaria ” (or " plague aviaire"), it was confused a long time with the Bird influenza or Avian flu, even with the Choléra of the hens. It can still be easily confused with the avian flu whose symptoms are identical. Only the analysis in laboratory makes it possible to pose a reliable diagnosis. More practical tests are awaited on the market.
History
As it was the case for the plague (or seizes up) avian, the veterinary surgeons think initially that the disease is of bacterial origin.In 1901, Centanni and its pupil Savonuzzi notes that the disease-causing agent of this zoonose (still confused with the influenza) crosses a porous ground filter, and that one cannot cultivate it in artificial mediums like a Bactérie. They conclude that it is thus about a different agent and much smaller.
Shortly after the discovery of the Virus Influenza has Avian flu, in 1926 at the time of an epizooty which decimates the hen houses of the Indies Dutchwomen Kraneveldt describes the disease of Newcastle or “ pseudo - avian plague ”, before Doyle which describes the disease in the Newcastle-upon-Tyne. They guess both that it differs from the avian plague, but the virus will be identified only in 1955 and will be classified in the family of the Paramyxoviridae, kind Rubulavirus.
In 1959, one distinguishes the Bird influenza HP (highly pathogenic) from the disease of Newcastle which for its pathogenic Hautement forms, is sometimes described as “ disease of Newcastle forms exotic ” (MNFE) or “ disease of Newcastle forms velogenic viscerotropic ”
- Like the influenza, the disease of Newcastle east to declaration obligatory , and followed by the GOOSE.
Surface of distribution
The virus can affect all the places where birds live. It is endemic in many countries of the world, but the breedings of certain European countries have profited from an unscathed statute for several years, which lets think that the breeding and the legal or illegal transport of the poultries, chicks or ducklings of 1 day, exotic birds or feathers, manures, carcasses, etc play - as for the avian flu - a significant role of tank and/or vector of the virus when the good practices there are not strictly respected and are not controlled.
Modes of dissemination
The natural virus is probably diffused by the migratory birds, but epizooties in the poultry seem related to the avicolous practices. The ACIA (Canadian Agency of inspection of food), as the majority of the experts estimate that the first source of diffusion of the virus are the people working in the sector of the poultry of which purchasers of poultry, feedingstuff deliverymen or the poultry breeders themselves. : The virus, very resistant, is easily conveyed on their clothes, under their shoes, on their instruments or vehicles.In the rich countries, the disease is supervised in the wildlife where it seems to pose less problem than in the breedings.
The wild birds can be very exposed with the viruses via the scrubbing of water of cleaning of the hen houses and especially via the spreading of droppings contaminated on the agricultural fields where many birds nourish themselves. The Co-composting of the excrements (whose pigeons) under good conditions the problem would regulate, but it is seldom practiced. (the droppings alone are too rich in nutrient to be made up, it should be mixed with plants, wood by putting the heap of compost at the shelter of the birds).
At the Man?
The health hazard is considered null with almost-no one for the Man who is not supposed being sensitive to the virus.The virus thus does not have an important incidence on the healthiness of the products of the poultry and eggs - for human consumption - although the eggs of sick birds quickly lose part of their qualities.
The literature announces however some cases of conjunctivitis induced at the man (conjunctivitis with bacillus of Weeks) when exposed to a strong concentration of the virus, or following contacts repeated and close with contaminated sick birds or products. The poultry breeders must avoid the formation of aerosols (by water brumisation on the dry substances likely to produce dust by ex), the contamination of eyes and the mucous membranes.
It is via the economic impacts for the poultry sector and the losses in the low-courses family of the poor or isolated families that the virus assigns the Man. In the poor countries the disease deprives the families of their first source of proteins, and in the rich countries it induces high costs: industrial poultry California and its producers for example were touched of 1971 to 1973 by a very pathogenic form of the virus. It was necessary to spend 50 million US dollars to eliminate nearly 12 million birds infected in this state, which did not prevent the virus from reappearing there into 2002 before diffusing in Arizona, in Nevada and Texas, generating new expensive measurements for its control (research, elimination, vaccination and follow-up).
The virus
The virus of the disease of Newcastle is a Paramyxovirus of the type 1. It is thus a virus with envelope, which explains a resistance rather high to the environmental conditions.They are virus ARN, with only one bit (with the difference of the influenza which has 8 bits), said monocaténaire. The viruses with ARN transfer easily and often what can make the strategies pharmaceutical and vaccine more complex and difficult.
The envelope of a diameter from 150 to 300 Nm presents 2 glycoproteinic types of spicules. It is characterized by:
- a glycoprotéine neuramidasic activity NR
- a glycoprotéine hémagglutinante H
- a glycoprotéine “F” which orders the cellular penetration of the virion.
Lifespan
The virus is very resistant to room temperature, There remains infectious:- a long time (several months) in the feces:
- 2 to 3 months on the ground, in a hen house,
- 7 to 8 months on a soiled shell,
- 2 years and more in one not cooked and frozen carcass
Incubation
The duration of incubation is of:- 4 to 6 days according to the GOOSE,
- 2 to 15 days according to other sources (ACIA by ex).
Three types of stocks
As for the influenza one classifies the layers according to their virulence while distinguishing:- Of the stocks velogenes (very virulent, inducing a mortality approaching or reaching the 100%, with an attack systemic, or at least visceral or nervous associated or not with respiratory disorders),
- Of the stocks mesogenes (fairly virulent) producing a respiratory affection with nervous disorders for a mortality reaching 50% in the young birds.
- Of the stocks lentogenes (slightly virulent, not mortals, producing some disorders respiratory, and sometimes not inducing any symptoms). They are for example the stocks Hitchner B1 and Sota.
Sources of virus
They are related to the bodies targeted by the virus, which varies according to the viral strain, the state and the immunizing history and perhaps the genetic inheritance of the touched bird. it will express the virus in:- bronchial secretions and feces,
- all parts of the carcass
Are the viruses excreted as of incubation and over one variable period at the time of convalescence, a few days at two weeks, seldom more, but for reasons badly included/understood, some Psittacidé S excrete of the viruses (by intermittent periods) during a few months at one year (even more?)
Means of disinfection
The virus is inactivated:- with 56°C/3 H or 60°C/30 mn
- by acid pH
Diagnosis
Clinical signs
respiratory signs:
sneeze, breathing haletante (dyspnea), nasal flow, cough;general signs:
They translate attacks of the systems digestive, hormonal, nervous and muscular: signs of depression (lifelessness, loss of appetite, fall of the production of eggs and shells rough and fine, containing a clear endosperm and liquid) are accompanied by problems of posture (the wings fall and trail along the body, the animal trails the legs is indolent), then the animal turns in round, with the head which oscillates, the neck which twists, of the stiff necks before the body tétanise. After which the bird dies quickly by asphyxiation probably.- - the bird produces a liquid and greenish diarrhea
- - Swelling (edema) of unquestionable part of the body, (cheeks, turn of the eyes, neck.
Lesions
The lesions vary according to the cases. They are close to those induced by the Bird influenza:- edema of interstitial or péritrachéaux fabrics (neck) in particular at the level of the breast-bone, accompanied sometimes by hemorrhage of the mucous membrane trachéale, pétéchies (red spots) and bruises on the mucous membrane of the glandular stomach, around of glands with mucus
- edema, hemorrhages, necroses and/or ulcerations of lymphoid fabric of the intestinal mucous membrane
- edema, hemorrhages or degeneration of the ovaries
As for the influenza, the identification is made by analysis in laboratory (and perhaps soon on biochip) leave:
- of taking away resulting from trachéaux and/or cloacal cleaning (or fecal taking away) in the live birds,
- or starting from bodies and of deposit extracted from corpses of birds;
The tests serologic are done on samples of coagulated blood or serum. They are Test of inhibition of the hemagglutination or tests ELISA.
Not to confuse with…
The differential diagnosis must carry on- the avian Choléra
- the Bird influenza or Avian flu
- the Laryngotrachéite of the bird
- the Variole to aviair E (diphteric form)
- the Psittacose (chlamydiose) at psittacidés the
- the Mycoplasmose
- the infectious Bronchite
- the Maladie of Pacheco of the parrot (psittacidés)
- and of possible results of traumatisms or dehydration, a renewal of insufficient air in the confined breedings.
- the Bird influenza or Avian flu
Target species of the virus:
- Poultry, especially the chicken which is most sensitive there, before duck then the goose. Potentially all domestic birds and savages can be infected by this disease.
- the pigeon ones can be decimated by the virus, as well as the breedings of species game. As example, in France, after the appearance of the symptoms of the disease on July 18th, 2005, the ministry for agriculture made proceed on July 20th to the euthanasia of approximately 35 000 partridges and 20 000 pheasants of a farm of Saint-March-of-Cost (department of Loire-Atlantique). The preceding case in France related to also a breeding of pheasants, but in the Département of the Pas-de-Calais in 1999.
- With the Japan of the breeding of parakeets and exotic birds was decimated.
- the Psittacidé S and other wild birds can carry the virus and play a part of tank (several months at one year of viral excretion for psittacidés.
Transmission channels
- fecal-oral contamination mainly, via secretions, especially the droppings of infected birds
- ground, frame, Food, water, objects, clothing. contaminated
Treatments, prevention
As for the influenza, there is no treatment, the touched birds are cut down and their disinfected environment.
Measures of precaution/prevention
They consists, in an international medical regulation framework, with:- To insulate the hearths (forty/makes an attempt 21 days before reintroduction of new manpower
- Détruire the birds of infected breedings or Co-talks and to eliminate their corpses under good conditions. The demolition of the infected batches must be total and without bloodshed, by gazage (the bromide of methyl is a disinfecting pesticide which kills the parasites of the ground sometimes proposed, but in addition to its toxicity and its cost, it presents the defect to belong to POPs (persistent organic pollutants); it is a gas with greenhouse effect, which contributes to the destruction of the layer of ozone and is the subject of a project of prohibition of use via the Protocol of Montreal. The ground of a hen house removed beforehand from the organic matters such as straw and droppings can be disinfected thermically (steam or slope with gas of a thermal Désherbeur) with destruction of eggs and the corpses.
- Measurements of hygiene (foot baths, even use of boots and clothing of single or reserved use (in the industrial breedings).
- To clean and disinfect regularly the buildings and objects likely to carry the virus, by taking care of the choice of the products used (cf risks of resistances and nosocomial)
- To fight against the parasites possibly vectors
- To avoid any contact between an industrial breeding and birds whose medical condition is unknown and to seek to limit them in the individual breedings and low-course. (nourrissage and drenching inside)
- Traçabilité and monitoring of transport and the contacts with the people
- Élevage by troops of only one age group by exploitation, but this implies work with hatcheries which can increase the risk to propagate massively and brutally the virus if it are not the subject of a very rigorous hygiene. Moreover industrial hatcheries which provide chicks, ducklings or oisons one day contribute to a genetic impoverishment very important and accelerated poultry, including in the stockbreeders bio when they use them. The selectors seek to produce stocks resistant to the grippaux viruses, but they generally do not remain it a long time vis-a-vis the exceptional capacities of change and diffusion of the viruses with ARN.
Medical disease prevention
The medical Prophylaxie is reduced primarily to vaccination (vaccines with alive viruses and/or in oily emulsion). Healthy chicks are vaccinated as of their the first four days, but the vaccine is more effective in second or third week. Other infections (with Mycoplasma) can worsen the vaccine reaction, risks circumvented by the use of vaccines with killed virus.Vaccination
The Vaccin S with alive viruses are effective, but they can contribute to propagate the virus.In the rich countries or large the breeding, vaccines with alive viruses lentogenes standard B1 (stock Hitchner B1, stock Sota) are used in atomizing (aerosol) for a vaccination of mass, and sometimes via water of drink or by intranasal way or intraoculaire.
Vaccines managed with the drink water are likely to be inactivated by residual chlorine, remainders of disinfecting in the pipes and containers.
The vaccines with inactivated viruses require an individual administration but offer a more durable immunity.
The vaccine is rather given to the age from 2 to 3 weeks if the infectious risk is considered to be weak, or at the first day if the risk is considered raised, with a recall 2 to 3 weeks later, then (according to the type of vaccine) of other recalls all 6 to 8 weeks for the stock Hitchner B1, - all 8 to 10 weeks for the stock Sota, and every 6 months for the vaccines with inactivated viruses.
The pigeons are vaccinated with inactivated viruses (2 injections in one month of interval as of 4 weeks of age) or by a specific vaccine.
Controls serologic (on a few tens of birds in a troop of industrial breeding) show that the vaccine was effective.
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