First identification of orf virus from an outbreak of contagious ecthyma in Polish sheep

Magdalena Larska; Agnieszka Nowakowska; Urszula Pękala-Duda

doi:10.2478/jvetres-2026-0035

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First identification of orf virus from an outbreak of contagious ecthyma in Polish sheep

Journal of Veterinary Research

Volume 70 (2026): Issue 2 (June 2026)

By: Magdalena Larska , Agnieszka Nowakowska and Urszula Pękala-Duda

Open Access

|Jun 2026

Figures & Tables

Erythema, pustules and crusts on the muzzle (A) and papules at the coronary band of the front feet (B) in Polish Blackhead sheep infected with orf virus

Amplification of orf virus genetic material from skin scraping samples from infected Polish Blackhead sheep. Analysis of PCR products with GIF5 and GIF6 primers with visible 408-bp amplicon (A), and with vIL03 and vIL04 primers with visible 300-bp amplicon (B). M1193 – molecular size marker; K-eks – no template control

Maximum-likelihood trees based on the nucleotide sequences of the granulocyte-macrophage colony-stimulating factor and interleukin-2 inhibition factor (GIF) (A) and viral interleukin 10 orthologue (vIL-10) (B) gene fragments of parapoxviruses detected in sheep in Kluczbork, Poland (sheep in red), Orf virus reference strain NZ2 (sheep in blue), two vaccine strains (marked with syringes) and other sequences retrieved from GenBank (all strains not isolated in the present research preceded by their accession Nos). Bootstrap values were generated for 1,000 repeats

Similarity matrix sequence heatmap for pairwise amino acid identity of granulocyte-macrophage colony-stimulating factor gene fragments of parapoxviruses detected in sheep in Kluczbork, Poland and other sequences retrieved from GenBank (these preceded by their accession Nos)_ The colour intensity of the grid indicates degree of similarity (darker for high and lighter for lower)

	PQ374835.1_ORFV-1V	PP565901.1_D1701V	ON805832.1	MF497783.1	MF175205.1	KM057389.1	KF666566.1	GU460372.1	AY605983.1	AY605975.1	OR452360.1	ON805831.1	LC476575.1	AY605988.1_NZ2	orf_virus_1_Poland_2025	orf_virus_2_Poland_2025	orf_virus_3_Poland_2025	orf_virus_4_Poland_2025
PQ374835.1_orf_virus_ORFV-1V2024_vaccine	100
PP565901.1_orf_virus_D1701_vaccine	100	100
ON805832.1_orf_virus_NAV_sheep_Spain_2018	100	100	100
MF497783.1_pseudocowpox_virus_Iraq-D.NO1_cattle_Iraq_2017	99.9	99.9	99.9	100
MF175205.1_parapoxvirus_sp._O.r.r._Svalbard_atlantic_walrus_Norway_2015	100	100	100	99.9	100
KM057389.1_orf_virus_2010-147_Muskox_USA(Alaska)_2010	100	100	100	99.9	100	100
KF666566.1_orf_virus_Xinjiang2_goat_China_2013	99.9	100	99.9	99.9	99.9	99.9	100
GU460372.1_orf_virus_Cam09_dromedary_camel_India_2008	99.9	99.9	99.9	99.9	99.9	99.9	99.9	100
AY605983.1_pseudocowpox_virus_N71.2Bos_cattle_Norway	100	100	100	99.9	100	100	99.9	99.9	100
AY605975.1_seal_parapoxvirus_Sc95.1Hg_grey_seal_United_Kingdom	99.9	100	100	99.9	100	100	99.9	99.9	100	100
OR452360.1_orf_virus_ORFVGoatBangladeshBLRI-012021_goat_Bangladesh_2021	100	100	100	99.9	100	100	100	99.9	100	99.9	100
ON805831.1_orf_virus_HRE_sheep_Argentina_2018	100	100	100	99.9	100	100	99.9	99.9	100	100	100	100
LC476575.1_orf_virus_S-1_japanese_serow_Japan_1985	100	100	100	100	100	100	100	99.9	100	100	100	100	100
AY605988.1_orf_virus_NZ2_New_Zealand	99.9	99.9	100	99.9	100	100	99.9	99.9	100	100	100	100	100	100
orf_virus_isolate_kluczbork_1_sheep_Poland_2025	100	100	100	99.9	100	100	99.9	99.9	100	100	99.9	100	100	100	100
orf_virus_isolate_kluczbork_2_sheep_Poland_2025	100	100	100	99.9	100	100	99.9	99.9	100	100	99.9	100	100	100	100	100
orf_virus_isolate_kluczbork_3_sheep_Poland_2025	100	100	100	99.9	100	100	99.9	99.9	100	100	99.9	100	100	100	100	100	100
orf_virus_isolate_kluczbork_4_sheep_Poland_2025	100	100	100	99.9	100	100	99.9	99.9	100	100	99.9	100	100	100	100	100	100	100

Differential diagnoses of sheep infectious diseases involving changes in the mouth, hooves, teats or external reproductive organs

Feature	Contagious ecthyma	Sheep pox	Foot-and-mouth disease	Bluetongue	Peste des petits ruminants
Causative agent	Orf virus (a DNA virus in the Parapoxvirus genus).	Sheeppox virus (a DNA virus in the Capripoxvirus genus).	Foot-and-mouth disease virus (an RNA virus in the Aphthovirus genus).	Bluetongue virus (an RNA virus in the Orbivirus genus).	Peste des petits ruminants virus (an RNA virus in the Morbillivirus genus).
Affected species	Sheep, goats and wild ruminants (zoonotic to humans).	Primarily sheep, but also goats (goatpox).	All cloven-hoofed animals (cattle, sheep, goats, pigs).	Sheep, goats, cattle and wild ruminants.	Primarily sheep and goats.
Clinical signs	Localised, proliferative skin lesions/scabs, mainly around the mouth and lips of young animals; heals without scarring in 4–5 weeks.	Severe, generalised pox lesions throughout the skin and mucous membranes, persistent fever, pneumonia and high mortality.	Fever, vesicular lesions (blisters) and erosions in the mouth (especially tongue), muzzle, feet and teats; causes lameness.	Oedema of the face/muzzle, soreness of the mouth and feet, oral ulcers, lameness and general weakness.	High fever, severe nasal/ocular discharge (which becomes purulent), diarrhoea, mouth lesions and bronchopneumonia.
Affected systems	Integumentary	Integumentary and respiratory	Epithelial surfaces	Multiple systems, including oral mucosa and circulatory system	Respiratory and gastrointestinal
Transmission	Direct contact with infected animals or contaminated environment.	Direct contact and possibly insects.	Direct contact, aerosols and contaminated fomites.	Vector-borne by Culicoides biting midges.	Direct contact and contaminated feed/water.
Mortality rate	Low (unless secondary infection or starvation in lambs).	Can be very high (up to 100% in lambs).	Low mortality in adult sheep; production losses are the main impact.	Variable, but can be high, especially in lambs.	Can be very high (up to 100% in outbreaks).
Zoonotic potential	Yes	No	No	No	No
WOAH notifiable disease	No	Yes	Yes	Yes	Yes
Present	Endemic worldwide	Africa, the Middle Eastand Asia^*	Asia, Africa and South America	Widespread globally	Africa, the Middle East and Asia^*

Similarity matrix sequence heatmap for pairwise amino acid identity of viral interleukin 10 orthologue gene fragments of parapoxviruses detected in sheep in Kluczbork, Poland and other sequences retrieved from GenBank (these preceded by their accession Nos)_ The colour intensity of the grid indicates degree of similarity (darker for high and lighter for lower)

	PQ374835.1_ORFV-1V	PP565901.1_D1701V	XM_005885225.2	OR900038.1	KY382358.2	AY606011.1	KF927101.1	KM098083.1	KM098071.7	NC_055142.1	PP943426.1	KM875472.1	JQ728421.1	AY606006.1_NZ2	orf_virus_1_Poland_2025	orf_virus_2_Poland_2025	orf_virus_3_Poland_2025	orf_virus_4_Poland_2025
PQ374835.1_orf_virus_isolate_ORFV-1V2024_vaccine	100
PP565901.1_orf_virus_isolate_D1701_vaccine	100	100
XM_005885225.2_brandts_bat_Russia_2011	94.2	94.5	100
OR900038.1_sheep_isolate_1_Egypt_2023	94.2	94.5	99.7	100
KY382358.2_seal_parapoxvirus_isolate_AFK76s1_seal_Poland_2015	94.4	94.1	97.6	97.4	100
AY606011.1_pseudocowpox_virus_isolate_No79.1Bos_cattle_Norway	94.1	94.3	98.3	98.2	97.7	100
KF927101.1_orf_virus_isolate_SV269_11_sheep_Brazil_2011	94.2	94.3	98.3	98.2	97.8	100	100
KM098083.1_orf_virus_isolate_2011-106_Dalls_sheep_USA_2011	94.1	94.3	98.3	98.2	97.7	100	100	100
KM098071.7_orf_virus_isolate_2005-167_mountain_goat_USA_2005	94.1	94.3	98.3	98.2	97.7	100	100	100	100
NC_055142.1_lymphocryptovirus_macaca/pfe-lcl-E3_long-tailed_macaque_USA_2012	93.9	94	98.1	97.7	97.2	98.3	98.3	98.3	98.3	100
PP943426.1_orf_virus_isolate_FX17_goat_China_2012	94.1	94.2	98.3	98.2	97.7	100	100	100	100	98.1	100
KM875472.1_bovine_papular_stomatitis_virus_strain_BV-TX09c1_cattle_USA_2009	94.5	94.7	98.6	98.7	98.1	98.6	98.6	98.6	98.6	97.9	98.6	100
JQ728421.1_pseudocowpox_virus_dromedary_camel_India_2011	92.9	93.1	94.2	93.7	93.2	93.5	93.5	93.5	93.5	93.6	93.6	93	100
AY606006.1_orf_virus_isolate_NZ2_NewZealand	100	100	94.3	94.4	94.1	94.1	94.2	94.1	94.1	94	94	94.7	92.9	100
orf_virus_isolate_kluczbork_1_sheep_Poland_2025	94.3	94.5	98.3	98.3	97.8	100	100	100	100	98.2	100	98.6	93.4	94.3	100
orf_virus_isolate_kluczbork_2_sheep_Poland_2025	94.2	94.4	98.3	98.2	97.7	100	100	100	100	98.2	100	98.6	93.5	94.2	100	100
orf_virus_isolate_kluczbork_3_sheep_Poland_2025	94.2	94.4	98.3	98.2	97.7	100	100	100	100	98.2	100	98.6	93.5	94.2	100	100	100
orf_virus_isolate_kluczbork_4_sheep_Poland_2025	94.3	94.5	98.3	98.3	97.8	100	100	100	100	98.2	100	98.6	93.4	94.3	100	100	100	100

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DOI: https://doi.org/10.2478/jvetres-2026-0035 | Journal eISSN: 2450-8608

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Language: English

Page range: 177 - 184

Submitted on: Dec 16, 2025

Accepted on: Jun 24, 2026

Published on: Jun 30, 2026

Published by: National Veterinary Research Institute in Pulawy

In partnership with: Paradigm Publishing Services

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© 2026 Magdalena Larska, Agnieszka Nowakowska, Urszula Pękala-Duda, published by National Veterinary Research Institute in Pulawy
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 70 (2026): Issue 2 (June 2026)

First identification of orf virus from an outbreak of contagious ecthyma in Polish sheep

Figures & Tables

Fig. 1.

Fig. 2.

Fig. 3.

Differential diagnoses of sheep infectious diseases involving changes in the mouth, hooves, teats or external reproductive organs

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