Effect of a Topical Formulation on Infective Viral Load in Lambs Naturally Infected with Orf Virus.

introductionOrf is a highly contagious eruptive viral disease of the skin and mucosa of sheep and goats. Although vaccination with live or attenuated orf virus is the preferred option for disease control, the vaccine is unavailable in many countries. Treatment of orf lesions involves standard hygiene and in numerous cases, management of presumptive secondary infections with antibiotics, increasing risks of antimicrobial resistance (AMR). The wound dressing formulation Tri-Solfen

methodsOne-month-old lambs (n=14), naturally infected with orf, were recruited from a farm during a natural outbreak of the disease. The animals were selected at the early stages of the infection and randomly divided into two cohorts: Group A (n=11) treated with the topical wound gel formulation (TS); and Group B (n=3) an untreated control group. Swabs were obtained before treatment (T0) and on days one (T1), 3 (T2) and 5 (T3) post-treatment, then submitted to direct DNA extraction with real-time PCR quantification, plus incubation with primary tissue cultures from ovine skin fibroblasts (OSF) and T-immortalized goat embryonic fibroblasts (TIGEF).

resultsAlthough no significant differences were found in the clinical progression of the lesions and PCR quantification (p=0.722) between these small cohorts, there was a significant difference (p<0.05) in reduction in infective viral load between the groups when assessed in OSF cell cultures between T0 and T3.

conclusionThese preliminary findings suggest that treatment of early stage lesions with this TS may reduce the infective viral load present in orf lesions.