Sheep Pox, Goatpox

Sheep pox (SPP), Goat Pox (GTP)

Changed on: 15.04.2021
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Sheep Pox and goatpox are smallpox diseases of small ruminants. Sheep and goat pox are harmless to humans.

Occurrence

Endemic in Asia, Asia Minor, the Middle East and Africa. Sheep and goat pox do not occur in Austria or in the EU, with the exception of Greece and Bulgaria.

Host animals

Small ruminants: sheep and goats. The extent to which wild sheep and goats are affected by this disease has not been scientifically clarified; infection of wild small ruminants with sheep or goat pox viruses cannot be ruled out.

Route of infection

Infection occurs by direct animal-to-animal contact, often via aerosols. Indirect spread, e.g. via contaminated stable equipment, tools, objects and transport vehicles is possible due to the longevity of the virus in the environment. Improperly treated animal hides and skins are also important sources of spread of the pathogens.

Incubation period

4-14 days

Symptoms

Frequently occurring symptoms are high fever (40-42 °C), nasal and eye discharge, pneumonia, disturbance of the general condition, languor as well as refusal to eat due to painful blisters in the mouth. The mortality rate depends on the breed of animal, the virus strain and the age of the animals. It varies between 50 % and 100 % and is particularly high in young animals.

Therapy

There is no therapy

Prevention

Intensive observation or short-term isolation of newly purchased animals. Live attenuated vaccines are available but not licensed in the EU. Prophylactic vaccinations are prohibited in all EU countries.

Situation in Austria

Sheep and goat pox are notifiable diseases of small ruminants. So far, the disease has not occurred in Austria.

Technical information

Sheep and goat pox are endemic in Africa, the Middle East, Asia Minor (Turkey) and Asia. In Europe, periodic outbreaks occur in Greece and Bulgaria (2013-2014, 2015, 2017). Affected animal species are sheep and goats. Infections of wild small ruminants have not been documented so far, but cannot be excluded. Human infection with sheep or goat pox virus is not known.

The import of sheep and goats from regions with endemic occurrence of sheep and goat pox (e.g. Turkey) is prohibited. The initial emergence of these animal diseases in Greece and Bulgaria could be attributed to illegal movements of individual infected animals in the course of transhumance and immigration movements, respectively, as well as to illegal trade in animals (EFSA Journal 2014;12(11):3885.). Movement of healthy animals within the affected EU Member States of Greece and Bulgaria only occurs with regard to breeding and slaughter. Further mechanisms of spread over geographically longer distances (e.g. via wild animals, birds or via vectors) have not been researched.

The causative agents of sheep and goat pox, sheep pox virus (SPPV) and goat pox virus (GTPV), belong to the genus Capripoxvirus. Sheep and goat pox viruses are double-stranded, enveloped DNA viruses (size: 170-260nm x 300-450nm). They occur in genetically distinct strains. Some of these viral strains may be specialized to the animal species named after them; however, some strains may infect both goat and sheep. Phylogenetically, sheep and goat pox viruses are distinct from Lumpy skin disease virus (LSDV), which is also a member of the capripox family; serologically, capripox viruses have yet to be differentiated.

The direct spread of the pathogens from infected to healthy animals takes place via aerosols containing pathogens through coughing, sneezing and vigorous head shaking. In the process, excretions containing pathogens (nasal and eye excretions, coughing mucus) are spread. Direct transmission of pathogens via open skin wounds in contact with infected animals is also possible. Sucking lambs and fawns can also become infected from the infected dam via skin lesions on the udder. Infected animals are already infectious at the first signs of skin lesions.

Indirect transmission occurs via arthropods (e.g. stable flies). Scientific studies on vectors are scarce. Virus-containing excretions in feed, water, wool, stable environment and transporters as well as poorly prepared or untreated hides of infected animals also contribute to the spread of the disease. The viruses can be detected in the saliva and nasal or ocular fluid of infected animals for up to 64 days, in skin lesions for up to 30 days, in crusts that have fallen off the lesions for up to 180 days, in urine for 15 days and in faeces for 61 days after infection. The viruses can persist in the environment for extended periods of time-for example, up to 180 days in pastures or 6 months in the shade in a barn building. The viruses are susceptible to temperatures above 70 °C (65 °C/30min., 56 °C/2h). Preferred pH environment is between 6.6 and 8.6. High alkaline or acid pH destroy most pathogens. 1 % formalin or chloroform, 2-3 % sodium hypochlorite and some other virucides can inactivate the viruses.

Symptomatology

The severity of the disease depends on the virulence of the virus strain, the breed and the age of the host animals. The course of the disease and the severity of symptoms are more pronounced in homologously infected animals. Young animals are more severely affected than older animals; morbidity is 70-90 %, mortality over 50 %. Mortality can be close to 100 % in lambs and fawns. Recovered animals have immunity to new infections throughout their lives.

Infection of animals usually occurs through open skin wounds or through the respiratory organs by pathogen-carrying aerosols. The appearance of first skin lesions begins 6 days after infection. By day 6, most animals are not infectious. The first symptoms are nasal and ocular discharge, fever (40-42 °C), respiratory problems, loss of appetite and depressed behaviour. Skin lesions first appear on the face, around the lip and nose region, and on the eyelids. Skin lesions are often also found on the udder and base of the tail, and sometimes under the wool. Smallpox lesions may occur in almost all internal organs - the oral cavity, nasal cavity, tongue, lungs and mucous membranes of the digestive and respiratory tracts. Lymph nodes, liver and spleen are affected to a lesser extent. After 21 dpi, recovery of the animals is possible. Animals no longer show clinical signs but may shed pathogens for up to 64 days after infection. In lambs, disease symptoms are more pronounced. Due to the painful lesions in the mouth, nasal area, respiratory tract and digestive tract, the young animals often refuse to eat and starve to death.

Therapy, control

Sheeppox and goatpox are notifiable animal diseases. The control of both diseases is therefore based on

  • the prevention of the introduction and spread of the pathogen due to trade restrictions with regard to animal trade and trade in animal products from affected countries
  • the early detection of the diseases
  • the "stamping out" method (culling of infected and suspected animals).

In case of outbreaks of sheep and goat pox, restrictions on the movement of animals and animal products as well as the establishment of protection zones around outbreak foci or other disease-specific restrictions are to be expected. After the culling of affected livestock, intensive cleaning and disinfection of the stables as well as a waiting period before new stocking are a prerequisite for renewed stocking. The observation and examination of sentinel animals is important for the further occurrence of infections.Attentuated live vaccines are available, but these are not licensed in the EU. Diagnostically, it is not possible to distinguish between vaccinated animals and those infected with a field strain. Prophylactic vaccination is prohibited in all EU countries.

Diagnostic

Sample type: live animals:

  • Skin lesions and/or skin crusts
  • Salivary fluid (native in tubes or swabs possible - no bacteriological swab transport media)
  • Nasal and ocular fluid (with swab - no bacteriological swab transport media)
  • blood (EDTA/heparin) and serum

Carcasses (dead):

  • whole carcasses
  • skin lesions and/or skin crusts
  • Lymph nodes
  • Spleen
  • lungs and altered regions of the respiratory tract
  • Nasal fluid (with swab - no bacteriological swab transport media)

Samples may be sent to the National Reference Laboratory for Capripox (Institut für veterinärmedizinische Untersuchungen Mödling) via the official veterinarian.

Detection method:

  • Pathomorphological examinations incl. electron microscopy
  • Molecular biological methods (PCR)
  • Detection of antibodies by ELISA
  • Serum neutralization test (SNT)
  • Virus cultivation in cell culture (for research purposes only)

Diagnostic methods are also used in exclusion diagnostics. Exclusion diagnostics not only allow early detection of an epidemic, but also serve to maintain the competence of laboratory diagnostic tests.For diagnostics see also Services - Small Ruminants

Contact, Forms

Institute for Veterinary Investigations Mödling (National Reference Laboratory for Capripox)Robert Koch-Gasse 172340 MödlingTel: +43 50 555-38112Fax: +43 50 555-38529E-Mail: vetmed.moedlingno@Spam@agesno.Spam.at

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