A survey of contagious ecthyma and molecular characterization of Orf virus in sheep and goats in Nigeria (2014-2016).

Background: Outbreaks of contagious ecthyma (CE) are frequently reported in sheep and goat flocks in Nigeria with severe clinical outcomes. CE is a debilitating and economically important disease primarily affecting sheep and goats caused by the Orf virus (ORFV). Despite field reports of CE in the country, there is no concise country-wide epidemiological data on the disease and limited genetic data of circulating Nigerian ORFV are available in the public domain. Aim: An epidemiological survey of CE and molecular characterization of ORFV circulating in Nigeria from 2014 to 2016. Method: Data were collected using designed questionnaires, administered to veterinarians and farmers in selected States of Nigeria. Samples were collected during passive surveillance for CE from 2014 to 2016 which were analyzed by polymerase chain reaction (PCR). The A32L and B2L genes of circulating ORFV were also characterized. Results: Analysis of the questionnaire showed that 69.54% (n = 82/118) of the farmers claimed to have experienced CE in their flocks with average morbidity and mortality rates of 25% and 15%, respectively. A total of 113 veterinarians participated in the study, with 69.9% (n = 79) familiar with CE and claimed CE causes morbidity rates of 25%-37% and mortality rates of 10%-15% in sheep and goats. Laboratory results revealed that ORFV was detected in 72% (18/25) of outbreak samples analyzed by real-time PCR. Phylogenetic analysis of A32L and B2L genes revealed that Nigerian ORFV sequences belong to clusters I and II and are similar to viruses from India, Ethiopia, and China. Conclusions: This study is the first nationwide epidemiological data on the status of CE in sheep and goats in Nigeria. It is also the first report of molecular characterization of two genes of ORFV circulating and causing outbreaks in small ruminants in the country. This study showed that CE is under-reported, widespread and of economic importance to sheep and goat farmers in Nigeria.

Co-infection of peste des petits ruminants and goatpox in a mixed flock of sheep and goats in Kanam, North Central Nigeria.

Peste-des-petits-ruminants (PPR) and Goat pox (GTP) are two devastating and economically important transboundary animal diseases of small ruminants in Africa and Asia that have been difficult to control. This study however, investigated an outbreak of PPR and GTP in a mixed flock of indigenous sheep and goats in Kanam, North Central Nigeria. A total of nine sera and seven tissues (lungs, spleen, scab and skin) samples were collected and analysed in the laboratory using competitive enzyme linked immunosorbent assay (cELISA) for PPR antibodies and polymerase chain reaction (PCR) for detection of PPR virus (PPRV) and GTP virus (GTPV). Gene fragments of the nucleoprotein of PPRV and the G-protein-coupled chemokine receptor (GPCR) of GTPV were amplified and sequenced to confirm the presence of the causative viruses. Serologically, antibodies to PPRV were detected in all (9/9) sera collected. GTPV and PPRV was detected in corresponding samples (42.8% n = 3/7) of the scab/skin samples collected by both PCR and RT-PCR technique. The phylogenetic analysis of PPRV revealed that the virus belongs to lineage IV and clustered with viruses from Gabon and Cameroon. Similarly, the GTPV also clustered with other sequences from Burkina Faso and Yemen. The positive cELISA, RT-PCR and PCR results from samples collected from the same animals confirmed co-infection of PPR and GTP in this mixed flock of sheep and goats. This is the first report of concurrent infection of PPR and GTP in mixed flock of sheep and goats in Nigeria. Our findings underscore the need for farmers to vaccinate their flock to control spread and economic losses as result of these diseases.