Diseases

Parapox

Download as PDF Download as XLS Download summary

Chapter select

Control Tools

  • Diagnostics availability

  • Commercial diagnostic kits available worldwide

    No universal diagnostic test in use. When available, diagnosis is mainly performed at academic institutions or in public health reference laboratories.

    GAP: Rapid (validated), point-of-care tests are not available.

  • Commercial diagnostic kits available in Europe

    No universal diagnostic test in use. When available, diagnosis is mainly performed at academic institutions or in public health reference laboratories.

    GAP: Rapid (validated), point-of-care tests are not available.

  • Diagnostic kits validated by International, European or National Standards

    None.
  • Diagnostic method(s) described by International, European or National standards

    None.

  • Commercial potential for diagnostic kits in Europe

    Recently, possibly due to the increase in severe outbreaks of disease, labs across Europe, the US, Japan, India and South Africa have shown an interest in the parapox-viruses. In most instances this has been to confirm diagnosis of disease outbreaks, thereby reducing the incidence of misdiagnosis. At present there are no routine diagnostic tests in use for poxviruses and this can lead to misdiagnosis with other pathogens causing vesicular disease in ruminants. Practical problems emerged during the 2001 pan-asiatic type O FMD outbreak in the UK because of the difficulty of diagnosing FMD in sheep and cattle. Nowadays this can be again a cause of concern due to the recent spread of Bluetongue virus in Northern Europe and vaccinia-like outbreaks in cattle in several countries.

    Better knowledge about PPV epidemiology will open the market for commercial diagnostics because negative testing for PPV infection will become a quality standard.

    GAP: These zoonotic infections share clinical manifestations and exposure risks with other, potentially life-threatening zoonoses (e.g., cutaneous anthrax) and are likely under-recognized because of a lack of clinical suspicion and widely available diagnostics.

  • DIVA tests required and/or available

    None available / Low requirement.

  • Opportunities for new developments

    A standard diagnostic test should be established to assess PPV associated disease across Europe.

    Developing a test(s) capable of distinguishing between the parapox-viruses and other agents causing vesicular disease in ruminants.

    Pen-side devices allowing veterinarians and physicians to rapidly distinguish PPV from other agents causing vesicular diseases in animals and life-threatening cutaneous zoonoses.

    GAPS:

    Specificity and sensitivity needs to be maximised against the library of virus strains from across Europe

    An assessment of worldwide PPV strain variability will be important to developing accurate diagnostics test that can differentiate between endemic and imported isolates. This may also allow for regional differentiation and will enhance epidemiological efforts.

    Differential diagnosis will also require an understanding of variation present among other agents causing vesicular disease and how they differ genetically and biologically.

  • Vaccines availability

  • Commercial vaccines availability (globally)

    Live fully virulent virus applied by scarification of the axilla. Currently, several orf vaccines are licensed:  Scabivax (Schering-Plough), Vaxall Orf Vaccine (Fort Dodge) and ECTIVAC, prepared by “Pasteur”-Bucharest. Tissue culture licenced in a minority of countries.

    ACAM2000 (Acambis, USA) and MVA are vaccines licensed in the US for prevention of smallpox in immune-competent and immune-compromised persons, respectively.

    During the smallpox era, lack of adherence to appropriate hygienic measures among recent vaccines led to instances of anthropozoonotic transmission of VV from dairy workers to cattle (and back) causing focal outbreaks of disease.  These outbreaks were documented in Europe, Asia, North Africa and North and South America.

    GAPS:

    There is no published information available on the level of usage of OV vaccines.

  • Commercial vaccines authorised in Europe

    There are few commercial vaccines against OV, with none having authorisation for use across the whole of Europe.

    Vaccinia virus Lister was approved by the World Health Organization for use in smallpox eradication and is currently licensed in the UK (Lister Elstree, Bavarian Nordic).

    GAP: There is no published information available on the level of usage of OV vaccines.

  • Marker vaccines available worldwide

    None.

  • Marker vaccines authorised in Europe

    None.

  • Effectiveness of vaccines / Main shortcomings of current vaccines

    OV: Live fully virulent virus that causes disease and if used off-label can result in disease outbreaks in flocks.

    Current vaccines against orf are successful in reducing the severity of the disease but can disseminate the vaccine strain of the virus which can cause disease.

    No sterile immunity is induced. Vaccination considered to be effective for 6 -12 months.

  • Commercial potential for vaccines in Europe

    There is considerable scope for improving the currently available vaccines against OV

    GAPS: Moderate if safety issues are dealt with.

  • Commercial feasibility (e.g manufacturing)

    National/Federal support underpins vaccine procurement and stockpiling in the United States.

  • Opportunity for new developments

    There is a need to improve vaccines against OV since current vaccines are fully virulent live viruses.

    It is most likely that protective immunity to OV requires the stimulation of a cellular response. It cannot be predicted if this will be achieved most efficiently by a non-infectious subunit vaccine, an engineered attenuated OV, or some other means such as a vector containing the appropriate OV genes. For this reason, it is important to pursue each of these lines of investigation.

    Deliver viral antigens in such a way as to stimulate a cell mediated Th 1 response, including the presentation of peptides on class 1 MHC.

    Most promising candidate is DNA vaccination.

    Alternative approach is generating neutralising antibody response directed against secreted PPV proteins that are unlike any host protein.

    GAPS:

    ·         Determine how the virus avoids the immune response

    ·         Determine how an effective vaccine can be achieved:

    o    Identification of virulence genes to facilitate the selection of virus components that are capable of inducing immune reactions without being blocked by counteracting viral proteins

    o    Determine which genes encode produce protective antigens able to stimulate protective immune responses. best at stimulating immune activities

    ·       Continued studies on the use of poxviruses as expression vectors to improve vaccine development and possibly gene therapy by exploiting their potential as immunomodulators.

  • Pharmaceutical availability

  • Current therapy (curative and preventive)

    There are no approved veterinary treatments for poxvirus-related infections.

    There are records of traditional or alternative remedies used for the treatment and prevention of OV infections in sheep and goats. Application of different oils (sesame and castor), the juice of Acra (Calotropis procera) and that of Thor (Euphorbia spp) have been used in India and in several African countries while Ilex aquifolium has been employed to cure and prevent ecthyma in the Netherlands and in France. The anti-orf virus activity of Cidofovir (HPMPC, CDV, Vistide®) was demonstrated in studies in vitro and ex vivo. In vivo, in experimentally infected lambs, it was shown that the topical application of cidofovir cream resulted in milder lesions that resolved more quickly than untreated lesions. Cidofovir also reduces the amount of viable virus found in the lesions and thus could be critical to reducing the incidence of disease on farms that have a persistent problem with orf. 

  • Future therapy

    Several promising compounds, developed under the auspices of bioterrorism preparedness, are currently under. investigation. There has been little consideration thus far of their potential application to the prevention and treatment of neglected poxvirus-associated zoonoses.
  • Commercial potential for pharmaceuticals in Europe

    Pharmaceuticals would be of greatest value in the event of an outbreak and or following an introduction event.

  • Regulatory and/or policy challenges to approval

    The acceptability of using antivirals in food animals is unknown, but use of these compounds for humans, companion and other high value animals (zoo animals) could be explored.

  • New developments for diagnostic tests

  • Requirements for diagnostics development

    Diagnostic tests for poxvirus-associated zoonoses should be developed such that rapid screening can be performed in the field by clinicians (veterinarians and physicians) to readily distinguish poxvirus-associated illnesses from other sources of infection.

    GAPS:

    Specificity and sensitivity need to be maximised against the library of virus strains from across Europe and worldwide. It will be important to developing accurate diagnostics test that can differentiate between endemic and imported isolates.

  • Time to develop new or improved diagnostics

    Short term. Assay validation will likely require collaboration with reference facilities.

  • Cost of developing new or improved diagnostics and their validation

    Limited.

  • Research requirements for new or improved diagnostics

    Limited.

    GAPS:

    •  An assessment of worldwide strain variability will be important to developing accurate diagnostics test that can differentiate between endemic and imported isolates. This may also allow for regional differentiation and will enhance epidemiological efforts.
    • Differential diagnosis will also require an understanding of variation present among other agents causing vesicular disease and how they differ genetically and biologically.
    • Sourcing negative sheep / cattle may prove difficult for validation purposes.
  • Technology to determine virus freedom in animals

    This technology does not exist and would be difficult to develop (CDC).

  • New developments for vaccines

  • Requirements for vaccines development / main characteristics for improved vaccines

    Requirement for a vaccine that does not cause disease in its own right. Multiple different approaches to vaccine development could be considered including, live-attenuated virus vaccines, DNA vaccines, live recombinant vaccines.

  • Time to develop new or improved vaccines

    Long term (5 years with full market authorization).
  • Cost of developing new or improved vaccines and their validation

    Unknown/ variable.  Will depend on the approach selected.

  • Research requirements for new or improved vaccines

    See Section “Vaccines availability – Opportunities for new developments”.

  • New developments for pharmaceuticals

  • Requirements for pharmaceuticals development

    Testing of anti-virals / excipients / delivery mechanisms.

    GAP:

    • efficacy after development of symptoms,  
    • low toxicity, 
    • low potential for development of resistance.
  • Time to develop new or improved pharmaceuticals

    2-3 years.

  • Cost of developing new or improved pharmaceuticals and their validation

    Unknown.

  • Research requirements for new or improved pharmaceuticals

    Robust animal infection model.

Disease details

  • Description and characteristics

  • Pathogen

    Family Poxviridae, subfamily Chordopoxvirinae.

    The genus Parapoxvirus (PPV) includes three members, bovine papular stomatitis virus (BPSV), pseudocowpox virus (PCPV) and orf virus (OV). The parapoxvirus of Red deer (PVNZ) has been recently reported outside New Zealand in Italy and Germany.

    The genus Orthopoxvirus (OPXV) includes three virus species of significant consequence to human and animal health: vaccinia virus/buffalopox virus (VV/BPXV), cowpox virus (CPXV), and monkeypox virus (MPXV).

    GAPS:

  • Little is known about prevalence
  • Inadequate disease recognition
  • Outmoded countermeasures
  • Few barriers to importation
  • Variability of the disease

    Routine PPV diseases are normally self-limiting with low impact on individual animals, although lack of thrift is common leading to delayed finishing times. Occasional severe outbreaks occur leading to loss of teats or to fatalities

    GAPS:

    Little is known about prevalence of severe disease. Nothing is known about risk factors associated with severe disease. Missing knowledge about the clinical and sub-clinical prevalence of PPV infections in cattle and small ruminants in EU member states.

  • Stability of the agent/pathogen in the environment

    Scabs contain millions of virus particles which, when they dry up and drop off the animal, will contaminate the environment for years. Very stable in dry environments.

    GAP: Stability of live virus under ambient conditions in nature is largely unknown.

  • Species involved

  • Animal infected/carrier/disease

    Zoonotic PPVs are:

    • Orf  (OV)– sheep/goats/reindeer/muskox/human
    • BPSV – cattle/camel/human
    • PCPV– cattle/reindeer/dromedary/human
    • a new GC rich Poxvirus resembling PPV was isolated from a human case possibly linked to a contact with horses

    All of these cause contagious skin infection.

    GAPS:

    Range of permissive hosts for interspecies recombination

  • Human infected/disease

    Yes, from benign and self-limiting to severe (hospitalisation).

    Reports exist of atypical proliferating forms of giant OV in immunosuppressed and several reports of complicated forms also in immunocompetent individuals.

    The number of reported complicated cases in immune-suppressed patients is increasing as well as cases linked to religious slaughtering and cases of human to human transmission.

    GAP:

    Nothing is known about risk factors associated with severe disease. 

    The number of reports on complicated orf virus infections, after religious slaughtering, seems to suggest that predisposing factors related to the ethnic background may contribute to the condition.

    Under-reported because it is seen as occupational hazard that normally is self-limiting.

  • Vector cyclical/non-cyclical

    None.

  • Reservoir (animal, environment)

    PPVs infect domestic and wild ruminants as well as wildlife species (e.g seal). VV are known to be capable of infecting several species of sylvan and peri-domestic rodents, which are thought to be important for maintaining local foci of infection. 

    GAPS:

    • A better understanding of the identity and distribution of reservoirs for poxvirus associated zoonotic agents.
    • Sylvatic transmission cycles and principal opportunities/risks for spill-over.
    • Subclinical infections either caused by OPXV or PPVs have been recently reported in cattle, horse and red deer. Subclinically infected animals may play the role of reservoirs.
  • Description of infection & disease in natural hosts

  • Transmissibility

    Highly transmissible (almost 100% morbidity on affected farms). PPVs infect via broken, scarified or otherwise damaged skin and replicates in epidermal cells following direct contact with infected animals or with contaminated fomites. PPV, VV/BPXV and CPXVs are transmissible by direct contact with infectious material, either cutaneous lesions or fomites contaminated with scab material or lesion exudate. The viruses establish infections in new hosts through breaks in the skin or across mucous membranes (particularly of the eye).  In certain cases, respiratory transmission is also likely.

  • Pathogenic life cycle stages

    PPVs  are epitheliotropic, infecting damaged skin and replicating in regenerating epidermal keratinocytes., Lesions are localised and progress from erythema to pustule and scab causing painful oral sores in nursing young or cutaneous infections in dairy workers (typically on the hands or arms). Lesions on individual animals can persist for several weeks; animal mortality is rare, but has been reported. In other cases, such as taterapox, no visible lesions were observed in the species attributed as the host.  Rodents and primates experimentally infected with MPXV typically demonstrate fever, weight loss, diminished activity and disseminated rash, often with signs of pneumonia, blepharoconjunctivitis, and/or anal sores. Manifestation of illness and mortality proportion are dependent on virus dose, route of infection, age and size of the animal etc. 

    GAPS:

    Several aspects of virus genotype-associated pathology remain undefined and are currently understudied.

  • Signs/Morbidity

    PPV progress from erythema to macule/papule/vesicle to pustule then scab usually around the mouth or nares of lambs, but also occasionally on the teats of nursing ewes or around the coronets. Primary lesions can be severe and proliferative, but generally resolve within 6 weeks. Reinfections are less severe and resolve more rapidly than primary ones, usually within 2 weeks. Virus is shed with scab material, and there is no evidence of systemic spread. Severe outbreaks of orf can occur where lesions are extensive and proliferative and do not  spontaneously regress. 

    GAPS:

    • Prevalence not known in EU member states
    • Possibility of mis-diagnosis with other pathogens causing vesicular disease in ruminants.
    • The sub-clinical occurrence of PPV is largely however in context with diagnostic surveillance of notifiable diseases such as FMD, Bluetongue, BVD-Mucosal Disease and BHV-1 parapoxviruses (PPV) have been frequently detected in skin biopsies and swabs. The sub-clinical occurrence of PPV is largely unknown however in context with diagnostic surveillance of notifiable diseases such as FMD, Bluetongue, BVD-Mucosal Disease and BHV-1 parapoxviruses (PPV) have been frequently detected in skin biopsies and swabs.
  • Incubation period

    3-4 days.

    GAPS:

    • Possibility for PPVs subclinical infections in animals.
  • Mortality

    The mortality rate of PPVs is usually less than 1% but secondary complications of OV can increase this rate to around 20 to 50%.

  • Shedding kinetic patterns

    Virus is principally shed during the symptomatic phases of illness. All scab that is shed into the environment is loaded with fully infectious virus. Viral DNA can be recovered weeks after symptom defervescence in animals experimentally infected in the laboratory and in rare instances live virus has been recovered from animals > 1 month after initial infection.

    OV virus in wool remains infectious for at least one month. 

    GAPS:

    The shedding caused by subclinically infected animals acting as reservoirs need to be further investigated.

  • Mechanism of pathogenicity

    GAP: Much is inferred from studies of vaccinia virus or ectromelia, but actual studies in reservoir, transmitting or “end” hosts have been limited.
  • Zoonotic potential

  • Reported incidence in humans

    Virtually all PPV species are transmissible to humans. Human infections with orf, reindeerpox, sealpox and pseudocowpox have been recorded in recent years across Europe. In the UK, orf virus infections are the most common viral zoontic reported to the public health laboratory.  One study conducted in New Zealand found a 4% annual OV incidence amongst workers directly involved in slaughtering sheep.  

    Multiple reports by CDC for OV.

    Monkeypox virus is communicable in humans.

    An increasing number of complicated cases after religious slaughtering is being reported.

    GAPS:

    Lack of epidemiological investigations.

    The incidence in humans is frequently unknown because the diseases are not notifiable.

  • Risk of occurence in humans, populations at risk, specific risk factors

    The majority of PPVs are transmissible to man with disease considered an occupational hazard to farmers, shepherds, veterinarians, animal handlers, meat and wool processors and also associated with religious slaughter of animals. Increasing number of cases in children exposed to infected animals in an occupational setting or during recreation (source CDC). There is a high risk of contracting orf infection from handling pelts and wool, and that direct contact with current lesions was not required.

    Increasing number of immune-compromised individuals augment the number of cases. The majority of PPVs are transmissible to man with disease considered an occupational hazard to farmers, shepherds, veterinarians, animal handlers, meat and wool processors and also associated with religious slaughter of animals. Increasing number of cases in children exposed to infected animals in an occupational setting or during recreation (source CDC). There is a high risk of contracting orf infection from handling pelts and wool, and that direct contact with current lesions was not required.

    GAPS:

    Many risk factors are unknown. It might be reasonable to investigate population specific contribution of the HLA haplotype leading to complications after infection with zoonotic poxvirusses.

  • Symptoms described in humans

    PPVs cause painful lesions on the hands, fingers and face that respond poorly to treatment. The viruses can cause a systemic reaction sufficiently severe to require hospitalisation. Reports exist of atypical proliferating forms of giant orf in immunosuppressed and reports exist also for immunocompetent individuals. Further complications such as erythema multiform, bullous pemphigoid, swan-neck deformity and paresthesia and autoimmune blistering disorders have also been reported following OV infection.

    GAPS:

    These zoonotic infections share clinical manifestations and exposure risks with other, potentially life-threatening zoonoses (e.g., tularaemia cutaneous anthrax) and are likely under-recognized because of a lack of clinical suspicion and widely available diagnostics.

    Specific treatments for individuals experiencing complications do exist, but availability of those biologicals and compounds that have been approved as therapies is limited.

  • Estimated level of under-reporting in humans

    Unknown since the diseases are not reportable.

    GAP: Diseases are not notifiable.

  • Likelihood of spread in humans

    PPVs human to human transmission is possible but usually limited to direct contacts.

    GAPS:

    Not known, few reports about man-to-man spread.

  • Impact on animal welfare and biodiversity

  • Both disease and prevention/control measures related

    Isolation and quarantine of new animals are useful prevention tactics.  

    GAPS:

    Efficient and safe vaccines providing long lasting immunity are missing

    Large scale prevention and control programs in animals have not been systematically evaluated for efficacy or acceptability.

  • Endangered wild species affected or not (estimation for Europe / worldwide)

    Orf has a severe affect (high mortality) in semi-domesticated reindeer and in muskox.

    GAPS:

    Prevalence in wildlife ruminants is unknown.

  • Slaughter necessity according to EU rules or other regions

    Ewes and cows, which suffer loss of mammary function due to PPVs, VACV BPXV, may have to be culled.  Cohorting, isolation and quarantine may be effective strategies.

  • Geographical distribution and spread

  • Current occurence/distribution

    PPV-associated infectious diseases are found throughout the world. Recently it was reported that during the past three years 40% of the flocks in the USA have been infected with orf virus (source CDC). 

  • Epizootic/endemic- if epidemic frequency of outbreaks

    Frequency of outbreaks is currently undefined. PPV infections are endemic wherever sheep / goats / cattle farmed. 

    GAPS:

    Frequency of outbreaks /affected herds is not known in EU member states and worldwide.

    Currently undefined due to under-reporting. No information about subclinical infection. In clinically affected herds up to 80% morbidity.

  • Seasonality

    Undefined.

  • Speed of spatial spread during an outbreak

    Appears to be very fast within a flock / herd.

  • Transboundary potential of the disease

    Only with animal movements.

  • Seasonal cycle linked to climate

    Dry season - it is believed that the presence of thistles in areas where the animals are grazing favours outbreak and spread – basically things that can break the skin.

  • Distribution of disease or vector linked to climate

    No arthropod vector.

  • Outbreaks linked to extreme weather

    Virus more stable in dry conditions.

    GAP: No information from countries with extreme climate differences.

  • Sensitivity of disease or vectors to the effects of global climate change (climate/environment/land use)

    No arthropod vector. Climate change may affect the distribution of disease via impact on reservoir or transmitting host habitats.

  • Route of Transmission

  • Usual mode of transmission (introduction, means of spread)

    Direct contact / infectious fomites. Always through broken skin. PPVs are not transmissible via respiratory routes.

  • Conditions that favour spread

    Previous outbreaks / Rough pasture / Housing / Over-crowding / intensive farming practises.

    GAPS:

    Conditions favouring virus transmission from one species to another remain poorly defined.

    Many risk factors remain unknown.

  • Detection and Immune response to infection

  • Mechanism of host response

    Vigorous humoral and cell-mediated response to infection. Neutralizing anti-bodies not normally found. Colostrum from vaccinated / previously exposed ewes has no protective effect. 

    GAP: Mechanism of protection not fully understood.

  • Immunological basis of diagnosis

    Detection of IgG response to whole virus.

    GAP:

    No robust or commercial antibody test.

  • Main means of prevention, detection and control

  • Sanitary measures

    Disinfection / steam cleaning required for food troughs, buildings etc. used with known affected animals. Appears to be effective.

    GAP:

    Obstacles for prevention and control of zoonotic poxviruses include, an absence of readily available diagnostic assays, lack of familiarity with human and animal clinical disease (among veterinarians and physicians), lack of vaccines and therapeutics to prevent virus acquisition/transmission, a current incomplete understanding of the burden and distribution of zoonotic poxviruses globally.

  • Mechanical and biological control

    Scabs contain millions of virus particles which, when they dry up and drop off the animal, will contaminate the environment. 

    GAP:

    Large scale prevention and control programs in animals have not been systematically evaluated for efficacy or acceptability.

  • Diagnostic tools

    For PPVs ELISAs and PCRs are available. Several laboratories in the EU including national public health (and defense) laboratories in the UK, Germany, Spain, France and Italy have the capacity to perform nucleic acid based testing for the presence of orthopox virus signatures in clinical specimens.  

    Several LAMP techniques, a new mini array method able to simultaneously detect OPXV and PPV and an OPXV ELISA have been recently published.

    GAPS:

    Missed or mistaken diagnosis constitutes a ground for reflection on the sometimes incapacitating consequences of the disease on certain categories of patients such as children and immunocompromised individuals and on public health in case of poxvirus zoonoses and other life-threatening cutaneous agents.

    Lack of translation of research results into commercial products for these neglected diseases.

  • Vaccines

    Limited licensed vaccines available for PPVs. All vaccines are fully virulent live viruses that can themselves cause outbreaks of disease.

    GAP: No vaccines are under development for specific use in animals.

  • Therapeutics

    None available commercially, but anti-virals have been tested successfully in the laboratory.

    GAP: No therapies are under development for specific use in animals and humans.

  • Biosecurity measures effective as a preventive measure

    Not using the vaccine on premises where there is no history of OV infection. Persons receiving smallpox vaccination should refrain from contact with domestic livestock or zoo animals for a defined period of time.

  • Border/trade/movement control sufficient for control

    Not normally practised, but imports/exports are occasionally affected.

  • Prevention tools

    Prophylactic vaccination and sanitary / bio-security measures.

  • Surveillance

    No routine surveillance programmes in place.

  • Past experiences on success (and failures) of prevention, control, eradication in regions outside Europe

    No country has eradicated the diseases. Prevention and control is normally a combination of vaccination and sanitary / bio-security measures.

  • Costs of above measures

    Costs of surveillance are relatively low (5 € per sample), but significant in times of low farm gate prices and in developing countries.

  • Disease information from the OIE

  • Disease notifiable to the OIE

    PPVs infections of domestic animals are not reportable to the OIE.

  • OIE disease card available

    No.

  • OIE Terrestrial Animal Health Code

    Not available.

  • OIE Terrestrial Manual

    Not available.

  • Socio-economic impact

  • Zoonosis: impact on affected individuals and/or aggregated DALY figures

    UNKNOWN: Numbers seldom reflect the real importance of the disease in the communities in which they occur. Poxvirus zoonoses fall into the category of neglected zoonoses with considerable potential to cause significant, even life-threatening, disease in humans and animals as well as profound negative impacts on agricultural productivity.

    GAP: The incidence is often unknown or greatly underestimated. Under-reporting leads to underestimating the true number of DALYs which can be averted by effective control.

  • Zoonosis: cost of treatment and control of the disease in humans

    Unknown.

  • Direct impact (a) on production

    Parapoxvirus infections and in particular orf have a great economic impact to those rural communities that are predominantly reliant on livestock farming for their livelihood. OV is in the top twenty most important viral diseases of sheep and goats globally in terms of impact on the poor.  Growth may be retarded in lambs affected with the mouth form of orf or with strawberry footrot. There may be a reduction in the reproductive performance of a flock if rams affected with the venereal form of orf become reluctant to mate. Lambing percentages may be reduced and/or the breeding season and lambing may be extended. Bottle feeding and the isolation of infected animals may also add to operating costs, reduction in milk production, extra veterinary costs are due to the usual occurrence of secondary infections on teats leading to mastitis. The reduction in milk production and the spread of these viruses could severely impact the economy. Reindeer infections cause important economic losses to indigenous people (Saami) in Northern Europe. All of these factors can result in increased prices of milk, cheese, meat, hides and other products.

    GAP: There are no published studies on the costs of PPV diseases in the EU and worldwide.

  • Direct impact (b) cost of private and public control measures

    Unknown. Initial impact likely to be high due to scientific uncertainty and public perception (fear) of poxviruses.

    GAP: No cost benefit analysis available.

  • Indirect impact

    Significant losses in productivity occur when the ability of young animals to feed is negatively impacted either due to the development of mastitis in the adult (often following secondary infection) or oral pain or obstruction in the juvenile. Infections rarely occur as individual sporadic cases, but rather emerge as focal outbreaks, often affecting the majority of animals within a given herd resulting in significant curtailment of dairy production for an affected producer.

  • Trade implications

  • Impact on international trade/exports from the EU

    Australia exports large numbers of live sheep (several million each year) to Middle Eastern markets. In the past the presence of OV infected sheep has been a problem and has resulted in shipments being not accepted. In light of this potential trade barrier, all sheep for live export must be vaccinated against OV prior to export.

    GAP: Unknown. Initial impact likely high due to scientific uncertainty and public perception (fear) of poxviruses. Surveys are necessary.

  • Impact on EU intra-community trade

    Occasional.

    GAP: Unknown. Initial impact likely high due to scientific uncertainty and public perception (fear) of poxviruses. Surveys are necessary.

  • Impact on national trade

    Occasional.

  • Main perceived obstacles for effective prevention and control

    No vaccine capable of providing sterile immunity for PPVs.

    Obstacles for prevention and control of zoonotic poxviruses include, an absence of readily available diagnostic assays, lack of familiarity with human and animal clinical disease (among veterinarians and physicians), lack of vaccines and therapeutics to prevent virus acquisition/transmission, current incomplete understanding of the burden and distribution of zoonotic poxviruses globally.

  • Main perceived facilitators for effective prevention and control

    Vaccination / bio-security / sanitary measures.

Risk

Main critical gaps

Conclusion

  • Research in this field may lead to a reduction in the incidence, and therefore in the impact, of parapoxvirus(PPV)-associated disease. This will not only have benefits for the health and welfare of affected animals, but should also reduce the zoonotic impact on human health. 

    There is a high and promising potential for improvement and standardization of PPV-infection diagnostics. Especially rapid and reliable diagnostic differentiation of PPV from high priority notifiable virus infections in cattle and small ruminants is urgently needed.

    Thoughtful and efficient use of resources may be necessary to ensure that issues related to the availability and development of safe vaccines and effective drugs are addressed.

Sources of information

  • Expert group composition

    Expert group members are included where permission has been given:

    Alessandra Scagliarini, Università di Bologna, Italy - [Leader]

    Colin McInnes, Moredun Research Institute, UK

    Andrew Mercer, University of Otago, New Zealand

    Giliane Trindade, University of Minas Gerais, Brazil

    Mathias Büttner, University of Leipzig, Germany

     

  • Reviewed by

    Project Management Board.

  • Date of submission by expert group

    April 2016

  • References

    Alian S, Ahangarkani F, Arabsheybani S. A  (2015). Case of Orf Disease Complicated with Erythema Multiforme and Bullous Pemphigoid-Like Eruptions. Case Rep Infect Dis doi: 10.1155/2015/105484.

    de Sant'Ana FJF, Leal FAA, Rabelo RE, et al.: 2013, Coinfection by Vaccinia virus and an Orf virus–like parapoxvirus in an outbreak of vesicular disease in dairy cows in midwestern Brazil. J Vet Diagn Inv 25:267-272

    Friederichs S, Krebs S, Blum H, Lang H, Büttner M. (2015). Parapoxvirus (PPV) of reddeer reveals subclinical infection and confirms a unique species. J Gen Virol. 96(Pt 6):1446-62.

    Gallina L, Veronese F, Farinelli P, Boldorini R, Delrosso G, Colombo E, Maldi E, Peli A, Scagliarini A. (2016). Erythema multiforme after orf virus infection. Epidemiol Infect 144(1):88-9.

    Inoshima Y, Ishiguro N. (2014). On-site visual diagnosis of parapoxvirus infection using a portable cordless incubator. Anal Sci 30(12):1169-73.

    Khalafalla AI, Al-Busada KA, El-Sabagh IM (2015). Multiplex PCR for rapid diagnosis and differentiation of pox and pox-like diseases in dromedary Camels. Virol J 12:102.

    Lakis NS, Li Y, Abraham JL, Upton C, Blair DC, Smith S, Zhao H, Damon IK.(2015). Novel Poxvirus Infection in an Immune Suppressed Patient. Clin Infect Dis 15;61(10):1543-8

    Li J, Song D, He W, Bao Y, Lu R, Su G, Wang G, Lu H, Zhao K, Gao F.(2013). Rapid detection of orf virus by loop-mediated isothermal amplification based on the DNA polymerase gene. Arch Virol 158(4):793-8.

    Meier R, Sommacal A, Stahel A, Grünert J, Hoffmann M. (2015). Orf - an orphan disease? JRSM Open. 7;6(6):2054270415593718.

    Osadebe LU, Manthiram K, McCollum AM, Li Y, Emerson GL, Gallardo-Romero NF, Doty JB, Wilkins K, Zhao H, Drew CP, Metcalfe MG, Goldsmith CS, Muehlenbachs A, Googe PB, Dunn J, Duenckel T, Henderson H, Carroll DS, Zaki SR, Denison MR, Reynolds MG, Damon IK. (2015):  Novel poxvirus infection in 2 patients from the United States. Clin Infect Dis 15;60(2):195-202.

    Rajkomar V, Hannah M, Coulson IH, Owen CM (2016). A case of human to human transmission of orf between mother and child.  Clin Exp Dermatol. 41(1):60-3.