Lumpy skin disease – epidemiology and clinical findings

Kiril Krstevski
University of Ss. Cyril and Methodius, Faculty of Veterinary Medicine, Lazar Pop Trajkov 5-7, 1000 Skopje, Macedonia
E-mail: krstevski@fvm.ukim.edu.mk

Lumpy skin disease (LSD) is an important transboundary disease of cattle, caused by LSD virus from the Capripox genus. Its presence results in substantial economical losses caused by reduced milk production, infertility and abortion, emaciation, permanent damage to hides, as well as restrictions or total ban of trade with live animals and animal products ^[1,2].
The clinical appearance of the disease is rather specific, thus enabling easy recognition and initial suspicion. LSD is characterized by persistent fever, enlarged lymph nodes, necrotic lesions (mainly localized in the mucous membranes of the oral cavity and upper respiratory tract), and the most prominent sign – development of multiple, firm skin nodules. Severity of the disease could differ from subclinical (up to 50% of experimentally infected cattle) to fatal (less than 10%). LSD is not highly contagious and it has relatively low morbidity which varies between 5 and 45%. The main mode of LSDV transmission is mechanical via blood-feeding insects, but little is known about the role and importance of other transmission routes (direct contact, seminal transmission, infected fomites) ^{[2, 3, 4]}. Until recently, LSD remained primarily confined to the African continent, with occasional but short lasting incursions in the Middle East countries. In 2012, new and severe outbreaks were reported in Israel and Lebanon, marking the beginning of a new Middle East LSD epidemic. Political unrest and collapsed veterinary services in Syria and Iraq, further complemented with the absence of effective control measures in the most of the neighbouring countries, aided for a rapid disease spread and increased risk for LSD introduction in Europe ^[5,6].
In August 2015, only one year after becoming endemic in Turkey, LSD was reported in Greece and the first introduction of LSD in Europe was announced. The disease continued to spread despite the control efforts, but remained limited to the southern Greek provinces. In April 2016, new disease outbreaks appeared unexpectedly in the northern regions, indicating the beginning of a wide Balkan LSD epidemic. Within less than 4 months, many Balkan countries reported their first LSD outbreaks: Bulgaria (13 April), Macedonia (18 April), Serbia (4 June), Kosovo (June), Albania (6 July) and Montenegro (21 July). Mass vaccination campaigns using homologous, attenuated LSD vaccines were launched in the affected Balkan countries, in response to the disease introduction. Vaccination, along with the removal of infected animals/herds and strengthened movement controls, are the principle tools used in the control of the Balkan LSD epidemic, and their effectiveness is yet to be assessed. For now, it remains clear that current LSD epidemic is a serious threat for the rest of Europe.
Elucidation of the key knowledge gaps related to the LSD transmission, efficacy and safety of the available vaccines, development of safe inactivated DIVA vaccines and serological tests for rapid screening, presents a great challenge, but it is essential for success in LSD control in Europe.

References

1. FAO (2013): Emergence of lumpy skin disease in the Eastern Mediterranean Basin countries. Empres Watch, Vol. 29, Rome.
2. World Organization for Animal Health – OIE (2016): Chapter 2.4.13. Lumpy Skin Disease. In Manual of standards for diagnostic tests and vaccines. Available at: http://www.oie.int/fileadmin/Home/eng/Health_standards/tahm/2.04.13_LSD.pdf (accessed 30/10/2016)
3. European Food Safety Authority [EFSA] (2015): Scientific opinion on lumpy skin disease; EFSA panel on animal health and welfare (AHAW). EFSA J. 13, 3986. doi: 10.2903/j.efsa.2015.3986.
4. Tuppurainen, E., Venter, E., Shisler, J., Gari, G., Mekonnen, G., Juleff, N., Lyons, N., De Clercq, K., Upton, C., Bowden, T., Babiuk, S., Babiuk, L. (2015): Review: Capripoxvirus Diseases: Current Status and Opportunities for Control. Transbound. Emerg. Dis.
5. Tuppurainen, E., Oura, C. (2014): Lumpy skin disease: an African cattle disease getting closer to the EU, Vet. Rec. 175 (12), 300-301.
6. Beard, P. M. (2016): Lumpy skin disease: a direct threat to Europe. Vet. Rec.,178 (22), 557-558.