Lumpy skin disease and its economic impact

Livestock production constitutes one of the principal means of achieving improved living standards in many regions of the developing world. The livestock sector globally is highly dynamic, contributing 40 percent of the global value of agricultural output and supporting the livelihoods and food security of almost a billion people. In many developing countries (in sub-Saharan African countries), livestock keeping is a multifunctional activity and plays a crucial role both in national economies and the livelihood of rural communities. Ethiopia basically comprises an agrarian society; the socio-economic activities of about 85 percent of the population are based on farming and animal husbandry. Diseases are an important cause of reduced productivity of meat and milk as well as draft, hides and dung fuel in the country. Lumpy skin disease (LSD) is among the most economically significant viral emerging diseases, which is characterized by high fever, enlarged lymph nodes, firm, and circumscribed nodules. It is a disease with a high morbidity and low mortality rate and affects cattle of all ages and breeds. It causes high significant economic losses as a result of reduced milk production, beef loss and draft power loss, abortion, infertility, loss of condition and damage to the hide.

World Organization for Animal Health (WOAH), known earlier as International des Epizooties, considers LSD as list ‘A’ disease that has the potential for rapid spread with ability to cause serious economic losses.  LSD is currently endemic in most African continents and has recently spread out of Africa into the Middle East in addition to Europe countries. It has become an important threat to the livestock and dairy industry in the Middle East and Africa.

Despite being a transboundary disease, LSD has caused an international ban on the trade in livestock and their products. It has a different geographical distribution from that of sheep- and goat-pox, suggesting that cattle strains of capripoxvirus do not infect or transmit between sheep and goats. A disease of cattle, LSD causes several disorders. Though all breeds and age groups are susceptible regardless of sex, Bos taurus are particularly more vulnerable to clinical disease than zebu cattle. Among Bos taurus, fine-skinned Channel Island breeds develop more severe disease because of their thin skin, although younger animals are usually affected and show more severe disease than adult ones and Asian water buffalo are also reported to be susceptible. Even though, the clinical severity of the disease depends on susceptibility and immunological status of the thin-skinned, the high-producing dairy animal Bos taurus breeds are highly susceptible against LSDV (lumpy skin disease virus), whereas indigenous (bos indicus) breeds such as zebu and zebu hybrids are likely to have some natural resistance against the virus. It is not known what genetic factors influence the disease severity. Lactating cows appear to be severely affected and result in a sharp drop in milk production because of high fever caused by viral infection itself and secondary bacterial mastitis. High ambient temperatures, coupled with farming practices to produce high milk yields, could be deemed to stress the animals and contribute to the severity of the disease in Holstein–Friesian cattle. The morbidity rate varies widely, depending on the immune status of the hosts (host susceptibility) and the abundance of mechanical arthropod vectors. An introduction of new animals to the herd was highly associated with the occurrence of LSD. There is no evidence or report that the virus can affect humans. LSD poses no zoonotic problems. Infected cattle are not a source of any infection for humans and milk is safe to enter the human food chain. Whilst it is not desirable to eat the flesh of infected animals, due to the likelihood of carcass contamination by secondary bacterial infections, no harm has been known to have resulted from its consumption. Hence, there is no evidence and description that the virus can affect humans. Disease impacts are generally easy to identify but may be difficult to quantify. Disease outbreaks often have broad, long-term effects on the livestock industry. The costs of animal disease can roughly be divided into direct costs, which include losses related to animal illness, death and less immediate impacts such as reduced fertility, and indirect costs, which encompass control costs, losses in trade and other revenues. Understanding the impact of animal disease and assessing its losses is useful for policy makers and farmers who may weigh the losses against the costs of disease control each at their own level. There has been very limited work carried out on the financial analysis of herd-level control of LSD. Therefore, the objectives of this study were to determine the direct financial losses of LSD related to milk loss, draft power loss, mortality and indirect losses due to treatment, and to assess the cost effectiveness of vaccination as a means of LSD control. Capri pox viruses are becoming an emerging worldwide threat to sheep, goats and cattle. LSD causes considerable economic losses due to emaciation, hide damage, temporary or permanent infertility in males and females, abortion, mastitis, loss of milk production and mortality of up to 40 percent, although mortality rarely exceeds three percent. Therefore, LSD is one of the economically significant diseases in Africa and the Middle East countries that cause severe production loss in cattle. WOAH categorizes the disease as modifiable because of its severe economic losses. The economic importance of the disease was mainly due to having a high morbidity rate rather than mortality. As a consequence, the financial implication of these losses is greatly significant to the herd owners, consumers and the industrial sectors, which can process the livestock products and by-products. Reports from Ethiopia indicate that estimated financial losses on the basis of milk, meat, beef, draught power, mortality, treatment and vaccination costs in individual heads of local zebu stood at $6.43, whereas for the Holstein Friesian it amounted to $58. In general, LSD is considered a disease of high economic pressure because of its ability to compromise food security through loss of draft power, reduced output of animal production, increased production costs due to increased costs of disease control, and disruption of trade in livestock and their products. Moreover, economic losses may be high due to contamination of carcasses and cost of inspecting meat as it damages the hides. Permanent damage to the skin and hide greatly affects the leather industry by triggering a ban on international trade in livestock and its products. Restrictions on global trade in live animals and animal products, costly control and eradication measures such as vaccination campaigns as well as the indirect costs because of the compulsory limitations in animal movements cause significant financial losses at the national level also. The LSD impact in terms of production losses and control costs was high, a median total economic loss of $1,176 ($2,735 in commercial and $489 in subsistence herd) per LSD affected herd. The losses were mainly from morbidity and mortality of cattle and were the greatest in highly productive animals. The largest component of the economic losses was due to mortality loss followed by milk loss and draft loss at both animal level and herd level losses. In Nepal, LSD has become rampant, three years after making inroads into the country. In the context of Nepal, it may be hypothetical to estimate the cumulative economic loss resulting from the disease. The author is senior veterinary health management consultant