Newcastle disease virus: Infectious substances pathogen safety data sheet

Section I – Infectious agent

Name

Newcastle disease virus

Agent type

Virus

Taxonomy

Family

Paramyxoviridae

Genus

Orthoavulavirus

Species

Avian orthoavulavirus 1

Synonym or cross-reference

Avian paramyxovirus 1; Avian avulavirus 1; Ranikhet disease; avian pneumoencephalitis; Newcastle disease; exotic Newcastle disease; velogenic Newcastle disease; virulent Newcastle disease; pseudo-fowl pest; pseudo-fowl plague; pseudo-poultry plague; avian distemper^{Footnote 1Footnote 2Footnote 3Footnote 4Footnote 5Footnote 6Footnote 7}.

Characteristics

Brief description

Newcastle disease virus (NDV) refers to strains/isolates assigned to the species Avian orthoavulavirus 1^{Footnote 1Footnote 6}. NDV causes Newcastle disease in avian species and outbreaks have resulted in significant economic losses for the poultry industry^{Footnote 8}.

Properties

NDV is a pleomorphic, enveloped virus measuring 300-500 nm in diameter^{Footnote 1}. It has a single-stranded, non-segmented, negative-sense RNA genome approximately 15.2 kb in length^{Footnote 2}. The genome encodes six structural proteins: nucleocapsid protein (NP), phosphoprotein (P), matrix protein (M), fusion protein (F), hemagglutinin-neuraminidase (HN), and large protein (L)^{Footnote 2}.

NDV isolates are classified into two groups: class I and class II^{Footnote 9}. Class I isolates are grouped under a single genotype and class II isolates are subdivided into genotypes I – XVIII. Virulence varies widely among NDV strains, which are categorized as avirulent (lentogenic), moderately virulent (mesogenic), or highly virulent (velogenic)^{Footnote 10Footnote 11}. Class I isolates are largely lentogenic, whereas class II isolates can vary from lentogenic to velogenic^{Footnote 10Footnote 12}. Amino acid sequence at the protease cleavage site of the viral F protein, which mediates virus-cell membrane fusion, is a determinant of NDV strain-specific virulence^{Footnote 13Footnote 14}.

Section II – Hazard identification

Pathogenicity and toxicity

NDV causes mild, self-limiting conjunctivitis in humans^{Footnote 15Footnote 16Footnote 17Footnote 18}. Symptoms include tearing, redness, and pain in the eye^{Footnote 16Footnote 18}. Influenza-like symptoms including fever, chills, headache, and malaise associated with NDV infection in humans are rare^{Footnote 15Footnote 18}. Symptoms typically resolve after approximately 10 days^{Footnote 18}.

Five different forms of Newcastle disease have been described based on clinical signs observed in infected chickens: velogenic viscerotrophic Newcastle disease (VVND), velogenic neutrotropic Newcastle disease (VNND), mesogenic Newcastle disease (MND), lentogenic Newcastle disease (LND) and asymptomatic enteric Newcastle disease (AEND)^{Footnote 8Footnote 9}. Generally, a decline in egg production may precede other clinical signs of Newcastle disease^{Footnote 8}. VVND is a systemic illness characterised by conjunctivitis, nasal discharges, diarrhoea, ruffled feathers, tremors, and paralysis^{Footnote 9Footnote 19}. Infected tissues show signs of haemorrhage; lesions are commonly observed in the digestive tract, spleen, and gut-associated lymphoid tissue^{Footnote 9Footnote 19}. Despite observations of neurological symptoms in affected birds, neurological lesions are absent^{Footnote 9Footnote 19}. VVND develops rapidly, with symptoms appearing 2 days post-inoculation and a disease course of 2 to 4 days^{Footnote 19}. Mortality rate of VVND is nearly 100%^{Footnote 19}. Clinical signs of VNND are primarily neurological (e.g., head twitching, tremors, opisthotonus, paralysis) with respiratory involvement in some cases^{Footnote 19}. VNND symptoms usually appear 5 to 10 days post-inoculation and mortality rate can range from 50 to 100%^{Footnote 19}. MND causes mild neurological and respiratory symptoms^{Footnote 9Footnote 19}. MND mortality is low (5-45%), but is associated with a temporary reduction in egg quality and quantity^{Footnote 3Footnote 19Footnote 20Footnote 21Footnote 22}. LND is associated with mild respiratory disease in young chickens but is avirulent for adults^{Footnote 9Footnote 19}. AEND is characterised by virus replication in the gastrointestinal tract of chickens that display no overt signs of disease^{Footnote 9}. Clinical signs of Newcastle disease in turkeys are similar to those observed in chickens, but are variable in other avian species^{Footnote 19}.

Although NDV vaccines protect birds from morbidity and mortality associated with Newcastle disease, vaccinated birds can become infected, shed virus, lose weight, and experience a temporary decrease in egg quality and quantity when challenged with velogenic NDV^{Footnote 3Footnote 21Footnote 23Footnote 24Footnote 25Footnote 26}.

Epidemiology

NDV has been isolated from every continent^{Footnote 9Footnote 27}. Some genotypes are geographically restricted, while others are prevalent globally^{Footnote 10Footnote 28}. Velogenic NDV strains have been implicated in four panzootics that have resulted in significant losses for the poultry industry^{Footnote 9Footnote 29Footnote 30}. The first panzootic originated in Asia and Europe in mid-1920s and spread slowly over the next two decades^{Footnote 9Footnote 29}. The second panzootic began in the late 1960s, spread across the world in 4 years, had substantial economic losses, and was largely brought under control in some countries through the introduction of Newcastle disease vaccines^{Footnote 29}. In the USA alone, the 1971-1973 NDV outbreak affected 391 premises and resulted in the culling of 11.9 million birds at an estimated cost of $318 million USD^{Footnote 31}. The third panzootic in the 1980s mainly affected pigeons, with minimal spread to poultry^{Footnote 29}. The fourth panzootic involving NDV genotype VII began in the late 1980s and is currently ongoing^{Footnote 9}. Newcastle disease outbreaks affecting commercial and backyard poultry continue to be reported in some countries^{Footnote 31}. A global NDV distribution map with current incidence information is published by The World Organisation for Animal Health (founded as OIE)^{Footnote 32}. In Canada, outbreaks of Newcastle disease affecting wild bird populations (e.g., cormorants) have been documented^{Footnote 33Footnote 34}, but no outbreaks or cases of velogenic NDV in domestic poultry have been reported to date^{Footnote 35}.

Clinical manifestations of Newcastle disease vary with age, immune status, environmental conditions, and species of bird^{Footnote 36}. In wild (unvaccinated) bird populations, NDV-associated mortality is highest among young birds^{Footnote 33Footnote 37}. Immunosuppressed birds are more vulnerable to pathogens including NDV. Heat stress has been shown to effect NDV-associated mortality rates^{Footnote 38}. Avian species differ in their susceptibilities to a given NDV strain^{Footnote 39Footnote 40Footnote 41}. Poultry workers, veterinarians, and laboratory workers are at higher risk of exposure to NDV^{Footnote 8}.

Host range

Natural host(s)

NDV infects over 200 avian species including species of chickens, turkeys, pheasants, ostriches, pigeons, and waterfowl^[8]. Humans are susceptible to NDV infection, and NDV is rarely isolated from other mammals^{Footnote 42Footnote 43Footnote 44}.

Other host(s)

Experimental hosts include mice^{Footnote 45}, hamsters^{Footnote 46}, rabbits^{Footnote 47}, and non-human primates^{Footnote 47Footnote 48}.

Infectious dose

The infectious dose for NDV administered to young chickens via the oral route is approximately 10⁴ EID₅₀ (median egg infective dose)^{Footnote 49}.

Incubation period

In humans, the incubation period for NDV causing conjunctivitis of the eye is approximately 24 hours^{Footnote 15}. In poultry, the incubation period for NDV is approximately 2 to 10 days^{Footnote 50}. NDV is shed in respiratory secretions and feces from 2 to 40 days post-inoculation^{Footnote 51}. Peak NDV shedding occurs 4 to 7 days post-inoculation^{Footnote 30Footnote 52Footnote 53}. In vaccinated birds, NDV shedding is reduced when the vaccine and challenge strain are antigenically similar^{Footnote 53}.

Communicability

In avian species, inhalation or ingestion of virus shed in respiratory secretions and feces of NDV-infected birds are the primary routes of infection^{Footnote 5Footnote 54}. Airborne spread has been implicated in some outbreaks^{Footnote 8}, and infection via inhalation of aerosolized NDV has been experimentally demonstrated^{Footnote 51}. Transmission of NDV can also occur via contaminated fomites including clothing, equipment, feed, and water^{Footnote 54Footnote 55}. Vertical transmission of NDV through eggs to hatching chicks has been reported^{Footnote 56Footnote 57}. NDV is highly contagious; upon introduction to a susceptible flock, nearly all birds become infected within 2 to 6 days^{Footnote 55}. Human infection with NDV typically occurs via direct contact with infected birds or carcasses and can result from exposure of mucous membranes of the eye^{Footnote 8Footnote 17}. There are no reports of human-to-human transmission^{Footnote 8}.

Section III – Dissemination

Reservoir

NDV is maintained in wild bird populations such as pigeons and waterfowl^{Footnote 29Footnote 31Footnote 58Footnote 59}.

Zoonosis

Zoonotic transmission of NDV from infected birds to humans can occur^{Footnote 8Footnote 15}. Human-to-bird transmission of NDV is likely possible but has not been demonstrated^{Footnote 8Footnote 15}.

Vectors

NDV has been isolated from flies; however, it is unclear if they harbour sufficient levels of virus to transmit infection^{Footnote 60}.

Section IV – Stability and viability

Drug susceptibility/resistance

Nitazoxanide, an anti-parasitic drug, and emetine, an emetic and anti-protozoal drug, showed antiviral activity against NDV in vivo^{Footnote 61Footnote 62}.

Susceptibility to disinfectants

Quaternary ammonium compounds (e.g., didecyl-dimethylammonium chloride (200 ppm)^{Footnote 63}, benzalkonium chloride (0.1%)^{Footnote 64}, formalin (0.1%)^{Footnote 65}, potassium monopersulfate (2500 ppm)^{Footnote 66}, glutaraldehyde (2.6%)^{Footnote 67}, phenolic compounds (e.g., o-phenylphenol)^{Footnote 67}, sodium hypochlorite^{Footnote 67}, and alcohol-based hand sanitizers^{Footnote 67} are effective against NDV. Beta-propiolactone (0.25%) treatment requires a long contact time (>200 min) to inactivate NDV^{Footnote 65Footnote 68}.

Physical inactivation

NDV is inactivated at pH greater than 12 (e.g., fresh charcoal ash and calcium hydroxide)^{Footnote 69}. NDV is heat-sensitive. Treatment regimes using temperatures 55 to 63°C can effectively inactivate NDV in egg products^{Footnote 70}. Cooking to a temperature of 70°C effectively inactivates NDV in chicken meat^{Footnote 71}. NDV infectivity is reduced by 90% upon exposure to sunlight for about 1 hour^{Footnote 41Footnote 72}.

Survival outside host

NDV can remain infectious on surfaces, in liquid suspension, and in tissues of infected avian carcasses for weeks to months when held at 0-1.7°C^{Footnote 73}. At room temperature, NDV remains infectious in litter for approximately 10-16 days^{Footnote 73Footnote 74}, and in water for 11 to 19 days^{Footnote 75}. At cooler temperatures, NDV can persist in poultry housing that previously held infected animals for approximately 1 month^{Footnote 73}. At room temperature, NDV viability is prolonged at higher relative humidity^{Footnote 75}.

Section V – First aid/medical

Surveillance

Clinical signs of Newcastle disease in birds can be confirmed by diagnostic tests. NDV antibodies in poultry sera can be detected using hemagglutination inhibition test (HI), enzyme-linked immunosorbent assay (ELISA), and neutralization test^{Footnote 9Footnote 76}. However, serological testing may be unable to differentiate between NDV-infected and vaccinated birds. Virus isolation involves sample processing and culture in embryonated eggs or cell culture followed by serological and/or molecular identification and pathotyping of NDV isolates (i.e., lentogenic, mesogenic, velogenic)^{Footnote 9}. Pathotyping methods include amino acid sequence prediction of F cleavage site, intracerebral pathogenicity index (ICPI), mean death time (MDT), and intravenous pathogenicity index (IVPI)^{Footnote 9}. NDV can be simultaneously detected and pathotyped in clinical samples using reverse-transcriptase PCR targeting the gene encoding fusion protein followed by sequencing^{Footnote 9Footnote 19Footnote 77Footnote 78}. ELISA^{Footnote 79}, microarray^{Footnote 80Footnote 81}, and immunochromatographic strips^{Footnote 82} have also been used to detect NDV.

Note: The specific recommendations for surveillance in the laboratory should come from the medical surveillance program, which is based on a local risk assessment of the pathogens and activities being undertaken, as well as an overarching risk assessment of the biosafety program as a whole. More information on medical surveillance is available in the Canadian Biosafety Handbook (CBH).

First aid/treatment

In humans, NDV-associated conjunctivitis often resolves without treatment^{Footnote 22}. There is no treatment for NDV-infected birds^{Footnote 35}.

Note: The specific recommendations for first aid/treatment in the laboratory should come from the post-exposure response plan, which is developed as part of the medical surveillance program. More information on the post-exposure response plan can be found in the CBH.

Immunization

Many commercial live and inactivated NDV vaccines are available for use in poultry to protect against clinical signs and mortality associated with NDV infection^{Footnote 9Footnote 83}. Vaccines using low virulence genotype I (e.g., I-2, V4, PHYLMV42, Ulster) and genotype II (e.g., LaSota NDV, VG/GA, Clone 30, B1) NDV strains are usually administered in live form^{Footnote 30Footnote 84}. Others vaccines include recombinant vaccine rP05, Komarov, Mukteswar, and ND.TR.IR^{Footnote 10Footnote 84Footnote 85}. Live lentogenic vaccines can be mass administered via drinking water and vaccine-coated feed^{Footnote 9Footnote 84Footnote 86}, or individually by eye-drops^{Footnote 87}. NDV vaccination regimes usually begin when chicks are 1 to 2 weeks of age^{Footnote 84}. In ovo vaccines (e.g., TS09-C)^{Footnote 88Footnote 89},virus-like particles^{Footnote 90}, plant-based vaccine production systems^{Footnote 91} and other recombinant vaccines^{Footnote 92Footnote 93Footnote 94} are under development.

Note: More information on the medical surveillance program can be found in the CBH, and by consulting the Canadian Immunization Guide.

Prophylaxis

None.

Note: More information on prophylaxis as part of the medical surveillance program can be found in the CBH.

Section VI – Laboratory hazard

Laboratory-acquired infections

Between 1942 and 1976, fifty-one laboratory acquired NDV infections occurred^{Footnote 15Footnote 95}. Cases involved splashes of infectious material into the eye and exposure to aerosols generated during post-mortem examinations of infected birds^{Footnote 15}. A lack of recent reports indicates that NDV-associated laboratory infections are either rare or underreported due to their mild and self-limiting nature^{Footnote 8Footnote 15Footnote 96}.

Note: Please consult the Canadian Biosafety Standard (CBS) and CBH for additional details on requirements for reporting exposure incidents. A Canadian biosafety guideline describing notification and reporting procedures is also available.

Sources/specimens

Specimens include feces, and cloacal and oropharyngeal swabs^{Footnote 9Footnote 84}. Post-mortem samples include cecal tonsil, lungs, kidney, liver, intestine, spleen, brain, and reproductive tract^{Footnote 9Footnote 31Footnote 50}.

Primary hazards

Exposure of ocular mucous membranes to infectious material^{Footnote 15}.

Special hazards

None.

Section VII – Exposure controls/personal protection

Risk group classification

Velogenic NDV is a Risk Group 2 human pathogen and Risk Group 3 animal pathogen^{Footnote 97Footnote 98} while lentogenic (i.e., Hitchner B1, La Sota, N79, V4) and mesogenic (i.e., NJ-Roakin, Mukteswar, Komarov, Roakin) strains of NDV are Risk Group 2 human pathogens and Risk Group 2 animal pathogens^{Footnote 97Footnote 98}.

Containment requirements

Containment Level 3 facilities, equipment, and operational practices as outlined in the CBS, is required for work with infectious or potentially infectious materials, animals or cultures involving velogenic strains of NDV^{Footnote 97}. Containment Level 2 facilities, equipment, and operational practices as outlined in the CBS, is required for work involving lentogenic and mesogenic strains of NDV^{Footnote 97}.

Protective clothing

The applicable Containment Level 2 or Containment Level 3 requirements for personal protective equipment (PPE) and clothing outlined in the CBS are to be followed for work involving NDV lentogenic and mesogenic or velogenic strains, respectively. At minimum, it is recommended to use a labcoat and closed-toe cleanable shoes, gloves when direct skin contact with infected materials or animals is unavoidable, and eye protection where there is a known or potential risk of exposure to splashes.

Note: A local risk assessment will identify the appropriate hand, foot, head, body, eye/face, and respiratory protection, and the PPE requirements for the containment zone must be documented.  

Other precautions

Laboratory workers that handle NDV should avoid contact with susceptible avian hosts^{Footnote 99}.

For Containment Level 2: A biological safety cabinet (BSC) or other primary containment devices to be used for activities with open vessels, based on the risks associated with the inherent characteristics of the regulated material, the potential to produce infectious aerosols or aerosolized toxins, the handling of high concentrations of regulated materials, or the handling of large volumes of regulated materials.

For Containment Level 3: All activities involving open vessels of pathogens are to be performed in a certified biological safety cabinet (BSC) or other appropriate primary containment device. The use of needles, syringes, and other sharp objects are to be strictly limited. Additional precautions must be considered with work involving animals or large scale activities.

Use of needles and syringes are to be strictly limited. Bending, shearing, re-capping, or removing needles from syringes are to be avoided, and if necessary, performed only as specified in standard operating procedures (SOPs). Additional precautions are required with work involving animals or large-scale activities.

Additional information

For diagnostic laboratories handling primary specimens that may contain NDV, the following resources may be consulted:

• Human Diagnostic Activities Biosafety Guideline
• Local Risk Assessment Biosafety Guideline

Section VIII – Handling and storage

Spills

Allow aerosols to settle. Wearing personal protective equipment, gently cover the spill with absorbent paper towel and apply suitable disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up (CBH).

Disposal

All materials/substances that have come in contact with the regulated materials to be completely decontaminated before they are removed from the containment zone or standard operating procedures (SOPs) to be in place to safely and securely move or transport waste out of the containment zone to a designated decontamination area / third party. This can be achieved by using decontamination technologies and processes that have been demonstrated to be effective against the regulated material, such as chemical disinfectants, autoclaving, irradiation, incineration, an effluent treatment system, or gaseous decontamination (CBH).

Storage

Containment Level 2: The applicable Containment Level 2 requirements for storage outlined in the CBS are to be followed. Primary containers of regulated materials removed from the containment zone are to be labelled, leakproof, impact resistant, and kept either in locked storage equipment or within an area with limited access.

Section IX – Regulatory and other information

Canadian regulatory information

Controlled activities with NDV require a Human Pathogens and Toxins licence, issued by the Public Health Agency of Canada^{Footnote 98}. Newcastle disease is an OIE-listed disease and a reportable disease in Canada^{Footnote 100Footnote 101}. Therefore, presence of a confirmed or suspected velogenic NDV-infected animal requires immediate reporting to a Canadian Food Inspection Agency’s (CFIA) district veterinarian in Canada. Importation of NDV requires an import permit, issued by the CFIA^{Footnote 101}.

The following is a non-exhaustive list of applicable designations, regulations, or legislations:

• Human Pathogen and Toxins Act and Human Pathogens and Toxins Regulations
• Health of Animals Act and Health of Animals Regulations
• Transportation of Dangerous Goods Regulations
• Reportable Diseases Regulations (animal)

Last file update

May 2020

Prepared by

Centre for Biosecurity, Public Health Agency of Canada.

Disclaimer

The scientific information, opinions, and recommendations contained in this Pathogen Safety Data Sheet have been developed based on or compiled from trusted sources available at the time of publication. Newly discovered hazards are frequent and this information may not be completely up to date. The Government of Canada accepts no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information.

Persons in Canada are responsible for complying with the relevant laws, including regulations, guidelines and standards applicable to the import, transport, and use of pathogens in Canada set by relevant regulatory authorities, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment and Climate Change Canada, and Transport Canada. The risk classification and related regulatory requirements referenced in this Pathogen Safety Data Sheet, such as those found in the Canadian Biosafety Standard, may be incomplete and are specific to the Canadian context. Other jurisdictions will have their own requirements.

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