Sheep Pox, Goatpox
Infection usually occurs via direct animal-to-animal contact, often via aerosols. Indirect spread via insects (e.g. stable flies, 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 pathogen spread.
Sheep and goat pox are endemic in Africa, the Middle East, Asia Minor (Turkey), and Asia (e.g., the Asian part of Russia, China, India). Since 2018, outbreaks have occurred repeatedly in the European part of Russia bordering Finland, Estonia, Latvia, Belarus, and Ukraine. In Europe, outbreaks have been reported in Greece (2013-2014, 2015, 2017) and Bulgaria (2013). In 2022, the animal disease reached Spain for the first time. Information on current animal disease activity in Spain can be found in the World Animal Health Information System.
Affected animal species are sheep and goats. Infections of wild small ruminants have been documented. In Europe, the European mouflon has been shown to be a susceptible species. Data on rock deer(Capra ibex) and chamois(Rubicapra sp.) are lacking. Human infection with sheep or goat pox virus is not known.
Importation of sheep and goats from regions with endemic occurrence of sheep and goat pox is prohibited. The first occurrence of these animal diseases in Greece and Bulgaria could be attributed to illegal movement 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.). The cause of the initial occurrence in Spain is suspected to be an entry from North Africa. Movement of healthy animals within the affected EU states of Greece and Bulgaria occurs only for breeding and slaughter. Other mechanisms of spread over geographically longer distances (e.g., via wild animals, birds, or via vectors) have not been investigated.
The causative agents of sheep and goat pox, sheep pox virus (SPPV) and goat pox virus (GTPV), belong to the capripoxvirus genus. The 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 capripoxviruses; serologically, capripoxviruses 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 violent head shaking. In the process, excretions containing pathogens (nasal, eye excretions, cough 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. Diseased animals are infectious at the first signs of skin lesions.
Indirect transmission occurs via arthropods (e.g., stable flies). Scientific studies on vectors are sparse. Virus-containing excretions in feed, water, wool, the barn environment, and transporters, as well as poorly prepared or untreated hides of infected animals, 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 the skin lesions for up to 30 days, in fallen crusts of the lesions for up to 180 days, in urine for 15 days, and in feces 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. 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 destroys most pathogens. 1% formalin or chloroform, 2-3% sodium hypochlorite and some other virucides can inactivate viruses.
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 as well as the expression of symptoms are more pronounced in homologously infected animals. Young animals are more severely affected than older animals; morbidity is 70-90% and mortality is over 50%. Mortality can approach 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 behavior. 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 can 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.
Sheeppox and goatpox are notifiable animal diseases. Control of both diseases is therefore based on
- preventing the introduction and spread of the pathogen due to trade restrictions on animal trade and trade in animal products from affected countries
- the early detection of the diseases
- In the event of an epidemic, measures prescribed by the authorities (e.g. the "stamping out" method (culling of infected animals suspected of being infected)
In the event of an outbreak of sheep and goat pox, restrictions on the movement of animals and animal products, and the establishment of protection zones around outbreak sites or other disease-specific restrictions are to be expected. After the culling of affected livestock, intensive cleaning and disinfection of the pens as well as a waiting period before new stocking are a prerequisite for renewed stocking. The observation and examination of sentinel animals is significant 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 animals infected with a field strain.
- Skin lesions and/or skin crusts.
- Salivary fluid (native in tubes or swab possible - no bacteriological swab transport media).
- Nasal and ocular fluid (with swab - no bacteriological swab transport media)
- Blood (EDTA/Heparin) and serum
- Whole carcass
- skin lesions and/or skin crusts
- Lymph nodes
- Lungs and altered regions of the respiratory tract
- Nasal fluid (with swab - no bacteriological swab transport media).
Samples can be sent to the National Reference Laboratory for Capripox (Institut für veterinärmedizinische Untersuchungen Mödling) via the official veterinarian.
- Molecular biological methods (PCR)
- Detection of antibodies by ELISA
- Serum neutralization test (SNT)
- Virus cultivation in cell culture (for research purposes only)
The diagnostic methods are also used in exclusion diagnostics. Exclusion diagnostics not only allows early detection of an epidemic, but also serves to maintain the competence of laboratory diagnostic tests.
Bluetongue, foot-and-mouth disease, plague of small ruminants, lip bark, ovine herpesvirus 2 (OvHV-2) infections, idiopathic ulceration, moderate limp, insect bites, photosensitivity.
Further information - useful references
Consumer health communication platform (KVG) - sheep and goat pox: www.verbrauchergesundheit.gv.at/tiere/krankheiten/schaf_ziegenpocken.html
World Organisation for Animal Health: www.woah.org
WOAH sheep and goat pox fact sheet: https://www.woah.org/en/disease/sheep-pox-and-goat-pox/
Food and Agriculture Organization (FAO): https://www.fao.org/home/en
Specific Diseases of sheeps and Goats: https://www.fao.org/3/t0756e/T0756E06.htm
Last updated: 03.08.2023