The avian paramyxoviruses (Avian Paramycxovirus) include a group of viruses included in the Paramyvoxiridae Family, Genus Avulavirus, with 11 different types, to date, for its antigenicity (serotypes), or by phylogenetic studies: avian paramyxovirus type 1 (Avian Paramyxovirus APMV- 1; Newcastle disease virus); Paramyxovirus Avian type 2 (APMV-2); Paramyxovirus Avian type 3 (APMV-3); Paramyxovirus Avian type 4 (APMV-4); Paramyxovirus Avian type 5 (APMV-5); Paramyxovirus Avian type 6 (APMV-6); Paramyxovirus Avian type 7 (APMV-7); Paramyxovirus Avian type 8 (APMV-8); Paramyxovirus Avian type 9 (APMV-9); Paramyxovirus Avian type 10 (APMV-10); Avian paramyxovirus type 11 (APMV-11).
The disease virus (NDV: Newcastle disease virus) is caused by virulent strains of avian paramyxovirus type 1 (APMV-1). This disease, since its description in 1926, is endemic in many countries, and for prevention vaccination is done in almost every country in which makes raising chickens on a commercial scale. There is great variation in strains of this virus, which made grouping on 5 pathotypes, according to clinical signs found in infected chickens: 1) Vicerotrópicas velogenic (highly pathogenic form often causing intestinal bleeding lesions); 2) Neutrópicas velogenic (causing high mortality after the manifestation of respiratory and neurological signs); 3) mesogenic (form with respiratory signs, and sometimes neurological, but low mortality); 4) lentogenic or respiratory (form with mild respiratory infection or subclinical); 5) Asymptomatic enteric (subclinical form of enteric infection).
This pathogenetic grouping is rare Pathotype distinct is present in the clinic, and infected birds often have overlapping clinical manifestations. Moreover, it may happen that mild clinical signs due to a little virulent strain, exacerbation when there superinfection other pathogen, or when there are adverse environmental conditions. Therefore, clinical signs, by themselves, are not the basis for diagnosis.
Virus Newcastle disease is a human pathogen. In people most frequent manifestation, and almost unique, it is conjunctivitis. It is appearing after 24 hours of exposure, with a short duration of the manifestations (1-2 days). Conjunctivitis, unilateral or bilateral, manifested by redness, tearing, eyelid edema, conjunctivitis, and subconjunctival hemorrhage. This ocular involvement is transient and does not affect the cornea. There is reported a strain of pigeons APMV-1 isolated from lung tissue, urine and feces of an immunocompromised patient who died of pneumonia case.
Other avian paramyxoviruses, their hosts and the problems caused
Other types of avian paramyxovirus found in other birds, as set forth below:
- APMV-2 (strain type APMV-2 / chicken / California / Yucaipa / 56), usually found in turkeys and pasarinos, although sometimes in chickens, and Psittacines, causing mild respiratory disease or problems in egg production, and sometimes serious illness if there exacerbations caused by other agents.
- APMV-3 turkeys (type strain APMV-3 / turkey / Wisconsin / 68), found in turkeys, which causes mild respiratory infection, and significant effect on egg production, exacerbated by coinfection other agents, or environmental conditions.
- APMV-3 psittacine (type strain APMV-3 / parakeet / Netherlands / 449/75), and found in psittacine pasarinos without affecting chickens.
- APMV-4 (type strain APMV-4 / duck / Hong Kong / 03/75), found in ducks, and geese, which have not found clinical manifestations.
- APMV-5 (APMV-type strain 5 / budgerigar / Japan / Kunitachi / 74), found in budgerigars and parakeets, without affecting chickens.
- APMV-6 (strain APMV-6 type / duck / Hong Kong / 199/77), found in turkeys, geese, turkeys and "rails", which causes mild respiratory disease, and slight increase of mortality in turkeys, but without disease in ducks and geese.
- APMV-7 (type strain APMV-7 / dove / Tennessee / 4/75), found in pigeons, turkeys and ostriches and causing mild respiratory infection in turkeys.
- APMV-8 (type strain APMV-8 / goose / Delaware / 1053/76), found in ducks and geese, without affecting chickens.
- APMV-9 (type strain APMV-9 / domestic duck / New York / 22/78), found in ducks, without clinical manifestations.
- Samples for virus isolation: tracheal or pharyngeal sample exudate, tracheal lavage, stool, or internal organs, as in the case of live or dead animals.
- Virus isolation: very useful test when performed by inoculation into the allantoic cavity of chicken embryo development.
- Molecular genomic detection: the ce RT-PCR tests are being increasingly used. The only drawback that may arise is the possibility of obtaining false negative results, with some samples containing inhibitors, as with the feces, but this inhibition is also dependent on the extraction methods used nucleic acid.
- Viral ID: preferably performed by hemagglutination inhibition tests using type - specific antibodies or by molecular methods. Molecular methods can cause problems by genetic variation that may exist between strains APMV-1
- Antibody detection: useful for detecting vaccine protection, but of little interest today, because there is a vaccination coverage.
Tests in IVAMI:
- Inoculation allantoic cavity of chicken embryos 9 to 11 days of development. Incubation at 37 for 4 to 7 days, and detecting haemagglutinating activity in the amniotic fluid. Confirmation by RT-PCR and sequencing, if desired.
- Molecular detection by RT-PCR, followed by sequencing if positive, to confirm.
- Live birds: oropharyngeal exudate samples, tracheal or cloaca (or stool) taken Swab (preferably impregnated Dacron swab or foam instead of nylon). Place the swab in a vial / tube containing 1.5 to 2 ml preferably sterile BHI broth (Brain-Heart Infusion; broth Heart Brain) (if were not available broth sterile BHI sterile PBS buffer may be used) and mix well for about 30 seconds to elute the sample taken in the broth, and carefully squeeze the swab against the inner wall of the tube. Sure seal the vial / tube. Keep the broth cold during sampling and during transportation to the laboratory. You must reach the laboratory within 24 hours of taking the sample; Otherwise, freeze and ship frozen.
- Dead birds: organ samples or feces. Introduce a fragment body of 5 mm (0.5 cm), or swab (preferably impregnated Dacron swab or foam instead of nylon) impregnated in stool, in a vial / tube containing 1.5 mL 2 preferably sterile BHI broth (brain-heart Infusion; brain heart broth) (if were not available sterile BHI broth, sterile PBS buffer may be used). If the sample is taken with a swab, mix well for 30 seconds to elute the sample taken in the broth, and carefully squeeze the swab against the inner wall of the tube. Sure seal the vial / tube. Keep the broth cold during sampling and during transportation to the laboratory. You must reach the laboratory within 24 hours of taking the sample; Otherwise, freeze and ship frozen.
Preservation and shipment of sample:
Refrigerated (preferred) for less than 24 to 48 hours.
Frozen: over 2 days.
Cost of the test: Consult firstname.lastname@example.org