Sokoto Journal of Veterinary Sciences, Volume 10 (Number 2). December, 2012 Sokoto Journal of Veterinary Sciences (P-ISSN 1595-093X E-ISSN 2315-6201) Olugasa & Anderson /Sokoto Journal of Veterinary Sciences (2012). 10(2): 56-60. http://dx.doi.org/10.4314/sokjvs.v10i2.10 Assessment of seroconversion against peste des petits ruminants vaccine among sheep and goats in Buchanan, Liberia BO Olugasa1&2* & JRN Anderson3 1Department of Veterinary Public Health and Preventive Medicine, Faculty of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria. 2College of Agriculture and Sustainable Development, Cuttington University, Suakoko, Liberia. 3Department of Animal Resource Technical Services, Ministry of Agriculture, Monrovia, Liberia. *Correspondence: Tel.: +2348035824221, E-mail: b.olugasa@ui.edu.ng, bolugasa@yahoo.com Abstract Serological response to a live commercial vaccine of Peste des petits ruminants (PPR) virus administered to sheep and goats in Buchanan, the capital city of Grand Bassa County, Liberia was assessed in view of its importance for effective restocking of small ruminants in the city. Forty-four paired serum samples (pre- and post-vaccination) were collected from vaccinated sheep and goats during a nation-wide campaign for food security promotion from March to October, 2011. Sheep and goats were vaccinated against PPR in late April, 2011. Pre-vaccination samples were collected in mid-April, 2011. Post-vaccination samples were collected in mid-October 2011 from the same 0 groups of sheep and goats (6 months after vaccination). Paired serum samples gathered were stored at -4 C until tested. Competitive Enzyme Linked Immunosorbent Assay (c-ELISA) was used to determine antibody levels against PPR virus. Only 34(77.3%) out of 44 paired serum samples were adequate in quantity and quality for the test. Test results indicated 27(79.4%) out of 44 paired serum samples increased significantly in antibody levels from pre- vaccination to post-vaccination levels that were equal or above threshold of Percentage Inhibition (PI > 50%) against PPR vaccine. The importance of these findings to effective veterinary services delivery for the control of this neglected animal disease in Liberia is discussed. The present seroconversion status against PPR virus is considered to be a milestone in rebuilding veterinary services systems in Liberia towards national efforts for food security after prolonged civil war (1989-2003) in the country. Keywords: Buchanan city, Liberia, Peste des Petits Ruminants, seroconversion, veterinary services. Introduction Peste des petits ruminants (PPR) is an acute, highly Animal Diseases (VACNADA) (GALVMED, 2012) had contagious and trans-boundary viral disease of offered technical support to Liberia to embark on sheep and goats with variable rates of morbidity and the control of this disease that militates against its mortality that can reach 100% and 90% respectively sheep and goats restocking programme, in line with (Singh et al., 2004; Singh et al., 2006; Singh et al., the national programme for food security in post- 2009). The disease is enzootic in several countries of war nation of Liberia. Peste des Petits Ruminants is a West Africa, contributing to high economic loss in vaccine preventable disease, and its vaccine is small ruminant production (Diallo et al., 2007; OIE, considered to be one of the most effective vaccines 2012). PPR is a killer disease of small ruminants and ever produced against animal diseases (Diallo et al., its effective control is considered to be capable of 2007; OIE, 2012). Nevertheless, trained manpower is enhancing small ruminant production, especially required both for effective vaccination and serum among rural families. The African Union InterAfrican samples collection needed in monitoring and Bureau for Animal Resources (AU-IBAR) through its evaluation of serological response to administered programme on Vaccines for the Control of Neglected vaccine (Esuruoso & Olugasa, 1997; Esuruoso & Page 56 of 64 (SJVS, Vol. 10 no 2) UNIVERSITY OF IBADAN LIBRARY Sokoto Journal of Veterinary Sciences, Volume 10 (Number 2). December, 2012 Olugasa, 1999; Olugasa et al., 2011; Olugasa et al. The purpose of this study was to assess serological 2012). response of sheep and goats against PPR vaccine The use of a live-attenuated vaccine, as was the case administered in Grand Bassa County as part of an in VACNADA-Liberia project requires maintainance overall impact of the opportunity for in-country of cold chain for the vaccine to remain potent when manpower training and development for animal administered. Ensuring cold chain requirement is health services delivery in Liberia. often difficult in many developing African countries (Sen et al., 2010). As a result, thermostable live- Materials and methods attenuated vaccine is often recommended in such Study location instance (Diallo et al., 2007; GALVMED, 2012; OIE, Buchanan is a port city in Liberia, a coastal town in 2012). The United Nations Food and Agriculture the central part of the country and the capital city of Organization (FAO) provided a support that put in Grand Bassa County (Figure 1). The town has a place a Veterinary Epidemiology Station in human population of 34,270 according to the Buchanan, Grand Bassa County, Liberia with national census figures of 2008. Located at some capability for cold storage for animal vaccines and 110 km distance southeast of Monrovia, at the o 1 o 1 other perishable biologic samples. Non- geographic coordinates of 05 52 N and 10 02 W. Governmental Organizations (NGOs) are involved in Small ruminant production is important to small ruminants restocking to empower peasant households in this largely farming community. Sheep families in the community to engage in livestock and goat meat are delicacies at major eateries and production. Official records indicate several efforts hotels in this city that is well known for tourism and to improve upon veterinary services delivery in the hospitality services. country and contribute to food production. Figure I: Buchanan city in Grand Bassa County, Liberia. Inset showing the fifteen Counties of Liberia Vaccine used for PPR campaign Vaccine cold-chain system Homologous live attenuated PPR vaccines are now The VACNADA Liberia project utilized the facilities of commercially available with high potency and safety the Government owned JF Kennedy Hospital, in pregnant animals (Diallo et al., 2007, OIE, 2012). Monrovia to store the PPR vaccine in cold room at TM o Pestevac , a live vaccine of strain PPR Nig 75/1 was -20 C until they were transported in batches to the used in 2011 VACNADA-Liberia project at Buchanan, respective County Agriculture Offices. The vaccine Grand Bassa. Page 57 of 64 (SJVS, Vol. 10 no 2) UNIVERSITY OF IBADAN LIBRARY Sokoto Journal of Veterinary Sciences, Volume 10 (Number 2). December, 2012 was kept in this facility for some 3-4 months before used to test sera collected in accordance with the the quantity for each County was sent a week ahead manufacturer’s protocol, earlier described by of its use on extensive field vaccination exercise. Anderson et al. (1991), Singh et al. (2004) and Singh Deep freezer and refrigerator were used to store the et al. (2006). Laboratory facility for the test was vaccine at Buchanan Epidemiology station. Cold pack provided by the Ministry of Agriculture at Central in hand-held flasks were used to transport vaccine Veterinary Laboratory, Fendel. Optical densities (OD) quantity needed per day on the field during of positive and negative controls were compared administration to sheep and goats. Vaccine was with those of paired test serum samples. Antibody diluted only in quantity needed to be used and titre was expressed as Percentage Inhibition (PI). PI TM completed per time on the field. Pestevac live that was equal to or greater than 50% was vaccine PPR Nig 75/1 was indicated by manufacturer considered positive for PPR antibody threshold as safe for use in sheep and goats above 3 months of value. age in both sexes and pregnant animals. A total of 6,000 doses of PPR vaccine was allocated to this city Results and its environs in Grand Bassa County in 2011 All the 34 pre-vaccination serum samples tested vaccination campaign. below threshold percentage inhibition (PI<50%) of antibody against PPR. Six out of 10 post-vaccination Sera collection and storage serum samples from St. Johns River were above Whole blood was collected through the jugular vein threshold antibody level against PPR in vaccinated in sheep and goats during and after vaccination. sheep and goats. Two out of 5 post-vaccination Some 1.5mls of blood were collected per animal and serum samples from District #1 had antibody level allowed to clot in a plain universal bottle. Serum was above threshold (PI > 50%). All post-vaccination collected from clotted blood and stored in sterile serum samples from Districts #2, 3 and 4 were above containers in refrigerator until they were tested. threshold in antibody level. A total of 27 (79.4%) Serum samples received at the Central Veterinary paired sera of sheep and goats seroconverted out of Laboratory were labeled and dated, indicating 34 tested (Table 1). The finding of 79% 0 source and animal species. They were stored at -4 C. seroconversion in the c-ELISA test was high performance showing that adequate seroconversion Detection of antibody against PPR in sera of sheep was achieved in the vaccination exercise in and goats Buchanan and environs. Commercial PPR diagnostic kit for competitive Enzyme Linked Immunosorbent Assay (c-ELISA) Discussion jointly produced by Centre de Cooperation Serological response of sheep and goats to live Internationale en Recherche Agronomique Pour le attenuated PPR Nig 75/1 vaccine in Buchanan, Developpement (CIRAD), Montpellier, France and Liberia was assessed in this study, using a Biological Diagnostic Supplies Limited (BDSL), United competitive enzyme linked immunosurbent assay (c- Kingdom, was purchased from Biological Diagnostic ELISA). The purpose of the study was to assess and Supplies Limited (BDSL), United Kingdom. This was Table 1: Seroconversion in sheep and goats against live attenuated PPR Nig 75/1 vaccine in Buchanan, Grand Bassa County, Liberia (April - October, 2011) Location Paired Serum Pre-vaccination Post-Vaccination Seroconversion Samples Antibody Titre Antibody Titre (%) Collected PI ≥ 0.5 PI ≥ 0.5 St. John’s River District 10 0 6 60.0 District #1 5 0 2 40.0 District #2 15 0 15 100.0 District #3 (Neekreen) 2 0 2 100.0 District #4 2 0 2 100.0 Total 34 0 27 79.4 Positive sera (PI ≥ 50%) Negative sera (PI ≤ 50%) Page 58 of 64 (SJVS, Vol. 10 no 2) UNIVERSITY OF IBADAN LIBRARY Sokoto Journal of Veterinary Sciences, Volume 10 (Number 2). December, 2012 evaluate impact of a nationwide vaccination exercise conducted on a larger sample size from the county in carried out in 2011 on immune status of small future. Nonetheless, the present laboratory result ruminants in the city. The results showed positive has informed the impact of vaccination and level of seroconversion among sheep and goats contributed to the training of technical staff at the against PPR vaccine. Central Veterinary Laboratory in Liberia, in the use of The national Ministry of Agriculture in Liberia had c-ELISA for evaluation of sheep and goats’ response instituted a nationwide mass vaccination campaign to PPR vaccine. An earlier report on evaluation of against PPR that started in March and ended in Peste des Petits Ruminants prophylactic programme December 2011 (MOA-RL, 2011) with technical in Akure, Nigeria (Olugasa et al., 2009) did not even support from the African Union InterAfrican Bureau use laboratory assessment. The present approach in for Animal Resources on a project for Vaccines Buchanan imply higher effort at monitoring and against Neglected Animal Diseases. The project in evaluation of PPR vaccination. This is moreso in that Liberia was aimed at helping to secure sheep and seromonitoring is hardly done to ascertain goats population health against a killer disease of vaccination outcome following PPR campaigns in the small ruminants. south-western Nigeria. A major limitation to this evaluation was the Administrative decentralization in the Ministry of absence of baseline information on total number of Agriculture that is ongoing in Liberia has contributed small ruminants in Grand Bassa County. This was to vaccine and biological diagnostic specimen attributed to several factors, including veterinary keeping facilities in Buchanan’s Grand Bassa County services delivery in a devastated national economy. Agriculture Office (MOA-LR, 2011). A Veterinary This situation has earlier been reported in Nigeria by Epidemiology Station provided by the United Esuruoso (1995). The present finding indicates a Nations Food and Agriculture Organization in the milestone in rebuilding veterinary services delivery TCP/3020/LIB projects (2010) has contributed to the in Liberia in line with the project goal of VACNADA cold chain maintenance in the 2011 PPR vaccination (GALVMED, 2012) and current efforts for veterinary campaign. This may indicate cumulative effect of manpower development in the sub-region (Olugasa animal health facility in Buchanan, has positively et al., 2011; Olugasa et al. 2012). impacted on the county. This corroborates the Earlier attempts to control PPR in Liberia preliminary report of the Ministry of Agriculture encountered major setback due to national financial (MOA-LR, 2011). It is expected that local people are constraints, as PPR was reported in Lofa County, supported leading to reduction in mortality losses Liberia in 2009 that resulted in the morbidity of 200 associated with PPR, food security through increased animals and the mortality of 139, out of a total of participation in livestock production, and improved 444 small ruminants (MOA-RL, 2011). Other job security. It is on this backdrop that one may reported cases of PPR outbreaks in other counties conclude that a milestone is attained in rebuilding were unable to substantiate the claims. The 2011 veterinary services delivery in Liberia in the case of mass vaccination against Pest des Petits Ruminants Grand Bassa County here investigated. was mainly supported by the AU-IBAR and the Continued support is needed for diagnostic services European Union in contributing to national capacity and timely vaccination of susceptible population for building for food security and animal health in successful control of PPR in sheep and goats in Liberia. Liberia received 750,000 doses of PPR Buchanan, Liberia. vaccine towards VACNADA project to undertake a nation-wide free-vaccination campaign. Several Acknowledgement households benefited from this exercise (MOA-RL, The nationwide mass vaccination campaign against 2011). PPR in sheep and goats in Liberia was made possible Other notable limitations in interpreting the present through support received from the European Union findings include the limited number of sample (44 and the African Union Inter-African Bureau for paired samples) submitted from Buchanan and Animal Resources (AU-IBAR) for VACNADA-Liberia environs for test, upon which the percentage project. The authors thank Mr. Abrahim Kamara for seroprevalence of 79.4% was based, compared to data provided at the Veterinary Epidemiology the 6000 vaccine doses allocated. It could therefore Station, Buchanan. be recommended that further test may be Page 59 of 64 (SJVS, Vol. 10 no 2) UNIVERSITY OF IBADAN LIBRARY Sokoto Journal of Veterinary Sciences, Volume 10 (Number 2). December, 2012 References Anderson J, McKay IA & Butcher RN (1991). 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