Background
Ethiopia has the most abundant livestock population among African countries with an estimated domestic animal number of 56.71 million cattle, 29.33 million sheep, 29.11 million goats and 54.5 million chickens are found in Ethiopia (CSA, 2016). The livestock sector plays a crucial role in the livelihoods of majority of human population in the country. The agricultural sector constitutes around 45-48% of the gross domestic production (GDP) of the country and livestock sector accounts an estimated 20% of the total GDP without considering other contribution like traction power, fertilizing and mean of transport (CSA, 2009; Gebreegziabhare, 2010). Even though the country is gifted with huge livestock population, production and productivity is by far underneath the expectation due to widespread of livestock diseases and other constraints (Livestock Master Plan, 2015).
Livestock diseases are the major cause of economic losses to the peasant farmers and pastoralists in Ethiopia amounting to hundreds of millions of birr annually. These diseases are currently widespread in all agro-ecological zones of the country and annual mortality rates due to these diseases is estimated to be 8-10% for cattle herds, 15% and 12% sheep and goat flocks respectively. It is expected that animal diseases reduce production and productivity of livestock by 50-60% per year (Ganeshkumar, 2012). Among the livestock diseases hampering productivity of the sector and restrict Ethiopia’s ability to participate in international trade, foot-and-mouth disease (FMD) is perceived as the most economically important transboundary viral disease of cattle both at national and house hold levels (OIE, 2010; Bayissa et al ., 2011; Asseged, 2005).
Foot and mouth disease (FMD) is an extremely contagious and acute viral disease of all cloven-hoofed animals and is considered as a bottleneck for livestock production and productivity, and is prompting trade embargos for livestock and livestock products (Mansley, 2011). According to the office of international des epizootics, FMD ranks first among the disease of animals (Mahy, 2005). It is caused by FMD virus (FMDV) which belongs to the genus Aphthovirus within the family Picornaviridae (Belsham, 2005). The disease is characterized by fever, loss of appetite, salivation, vesicular eruptions in mucosa of the mouth, skin of the inter-digital spaces and coronary bands of the feet and teats, and sudden death of young stock (Quinn, 2005; OIE, 2009). Foot and mouth disease virus (FMDV) exists as seven immunologically distinct serotypes; namely, O, A, C, Asia 1, Southern African Territories (SAT)-1, SAT-2 and SAT-3 (OIE, 2004) with distinct immunologic, antigenic and genetic properties. The seven serotypes also differ in their distribution across the globe (Rufael et al ., 2008; Ayelet et al ., 2009). Currently, five FMDV serotypes (O, A, C, SAT-1 and SAT-2) are identified in Ethiopia out of the seven serotypes of the virus (Ayelet et al ., 2009; Negussie et al ., 2011). Within each serotype, there are many bio typical strains and topotypes which can be identified by genetic and immunological tests and infection with one serotype does not confer immune protection against another (OIE, 2012). Type O and A are the dominant serotypes responsible for substantial economic losses (Negussie et al ., 2011). Generally, studies undertaken on FMD so far revealed the existence of the disease in different parts of the country, with seroprevalence varying from 8.18%-44.2% in different part of the country (Mohamoud et al ., 2011; Jenbere et al ., 2011).
The disease spreads rapidly by movement of infected animals or mechanically via fomites such as clothing, shoes, vehicles, and veterinary instruments (Jibat et al ., 2013). The reasons for the rapid spread to fully susceptible population is due to its highly infectious nature of the virus, production of high titer in respiratory secretions and large volumes of droplets and aerosols of virus shed by infected animals, stability of virus in such droplets, rapid replication cycle with very high virus yields and short incubation period of the virus (Rweyemamu et al., 2008). FMD is the major endemic disease in Ethiopia with abundant socioeconomic importance as a result of reduced production, deaths in newborn animals, huge cost of veterinary services, restricted animal and meat movement locally and between countries (Knight-Jones and Rushton, 2013). Moreover, livestock and livestock product exports to the Middle East and African country has been hampered because of the presence of FMD recently (Bayissa et al ., 2011). The Egyptian ban of 2003 on Ethiopia’s livestock market alone resulted in market loss of 14.36 million USD and it is a threat to Ethiopia’s live animal export and export of animal products (MoARD, 2007 and MoARD, 2009).
In Ethiopia, outbreak of FMD frequently occurs in the pastoral herds of the marginal low land areas of the country (Mesfin, 2011). Absences of livestock movement control coupled with absence of systematic disease surveillance contribute a lot for outbreak of FMD in the pastoral herds of the marginal lowland areas of Ethiopia (Sahle et al ., 2004). There is limited information regarding to FMD virus serological status which may help to generate important baseline information about the disease in the study areas. Hence, the present study was anticipated to determine the seroprevalence and assess potential risk factors associated with occurrence of FMD virus in selected districts of afar region.