Peter Windsor, Isabel MacPhillamy, Francesca Earp
The University of Sydney
A report was received by Franny that on April 11th, of an outbreak of Foot-and-Mouth Disease (FMD) occurring in large ruminants in Mueangkay village near Luang Prabang city in Luang Prabang province of Laos. This village provides buffalo ‘for rent’ to the local buffalo dairy for the unique buffalo dairy products now available in Luang Prabang. As Franny was leaving Laos for a short trip to home, she contacted Peter in Australia who immediately contacted Dr Syseng Khounsy of the Department of Livestock and Fisheries (DLF), our in-country leader of our ACIAR and DFAT funded projects in Laos. Dr Syseng then contacted DLF field staff who verified the report and a team was assembled to visit the village, accompanied by Mr Chick Olsson of 4 Seasons Pty Ltd. Chick was able to return to Luang Prabang from Bangkok where he was on his way home from a recent field visit with the MLR group, examining logistics of potential manufacture of molasses mineral blocks in Laos.
The team and Chick donned their PPA (personal protection attire) to minimise virus contamination, and visited the village on April 12th to examine animals, collect samples and to potentially treat the FMD lesions with the wound formulation Tri-Solfen. The outbreak involved 99 buffalo and 37 cows of a population of 194 buffalo and 44 cows, from 136 households. Clinical observations were that the normally quiet and passive animals were ‘upset’ and reluctant to move, with difficulty in restraining them by the ‘bleeding pole’ method commonly used in developing countries where cattle crushes are largely absent. Both vaccinated and unvaccinated buffalo and cattle were present and affected. Closer examination confirmed the presence of typical lesions of FMD, observed as moderate to severe ulcerations of the gums, nasal tissue and interdigital areas of the feet.
All affected animals were treated with Tri-Solfen sprayed directly onto the oral and foot lesions. The spray coated the lesions without run-off, with total doses between 10-30ml applied per animal. They were extremely well tolerated by animals and farmers, the team, Chick and Peter who was observing via video link, noted that the therapy resulted in immediate improvement in the demeanour and locomotion of the animals, with no adverse events observed. During follow-up interviews a week later, the farmers described how impressed they were that the treatment provided such a rapid improvement in behaviour that indicated a dramatic reduction in pain. ‘They also described that there was rapid improvement in the healing of the lesions, with animals able to eat within 2 days, and lesions having recovered within 3-5 days. This is considered a marked improvement from known disease progression and recovery times for FMD-affected animals. As of May 17th, this is the only known outbreak where Tri-Solfen has been used for FMD, although the Lao veterinary authorities have now registered the product for this purpose and further supplies have been delivered for use in further outbreaks.
Tri-Solfen® is a commercial wound therapy product developed in Australia (by Medical/Animal Ethics Pty Ltd) as a ‘spray and stay’ pain relief formulation for use by farmers on sheep, particularly during the mulesing operation that provides lifetime protection agains blowfly strike. It contains the local anaesthetics lidocaine hydrochloride (50g/L) and bupivacaine hydrochloride (5g/L), adrenalin (1:2000), and the antiseptic cetrimide (5g/L) in a gel base. As the components have short half lives and been commonly used as individual treatments by veterinarians for many years there is minimal risk of residues. In addition to this new registration for FMD in Laos, Tri-Solfen is registered for mulesing, castration and tail docking in sheep and dehorning and castration in cattle in Australia, plus disbudding in calves in New Zealand.
Tri-Solfen has a pH of ~2.7 so has anti-viral activity that may limit virus transmission during outbreaks. However, it was the positive clinical impacts that were immediately recognised by farmers that most impressed the observers, with all affected animals in the village presented for examination and treatment with the ‘new medicine’. An intervention that encourages farmers to seek treatment, is likely to decrease the time taken for reporting of FMD and increase the proportion of the affected population presented for examination and treatment with an ‘easy to use’ topical antiviral medication. This is likely to improve disease reporting and response capacities of animal health authorities and may well influence the spread of the disease during outbreaks. Further, as Tri-Solfen does not contain antibiotics, it is a welcome alternative to the common practice of treating FMD with topical or injected antimicrobial drugs. Certainly, a ‘new medicine’ that minimises the suffering of FMD-affected animals, removes the risk of antimicrobial residues from therapy for FMD, and reduces the socioeconomic losses of farmers in Laos and potentially the many countries of the world where FMD is still an active threat to food security and trade, is a welcome discovery. The observations on April 12th near Luang Prabang, indicate the huge potential of Tri-Solfen in having a profoundly positive impact on the health and welfare of livestock-owning families and their animals in the future.