This pressure has already manifested itself in the FDA withdrawing the registration of quinolone antibiotics. There is thus a growing need to identify other options for the control of diseases in poultry.

Mentofin is a natural, water soluble concentrate based on the ethereal oils , menthol and eucalyptus. Previously, the safety of Mentofin treatment of both broilers and layers were established.

In these experiments the in vitro and in vivo efficacy of Mentofin has been demonstrated. It was established that the minimum inhibitory concentration (MIC) of Mentofin for E. coli was 1.33 per cent and 2 per cent for Pseudomonas aeruginos.

The MIC against Newcastle disease virus, determined in SPF eggs, was found to be between 0.5 per cent and 0.25 per cent, with some antiviral activity still detected at a dilution of as low as 0.125 per cent. The LD50 of Mentofin in embryonated eggs was found to be 1 per cent.

The efficacy of Mentofin for the control of infectious coryza was studied in an experimental challenge experiment in which unvaccinated chickens were challenged with the highly virulent serovar C-3 strain of Avibacterium paragallinarum. One group of birds received no treatment and acted as the control group. There were two experimental groups which received Mentofin treatment via the drinking water. In one group, chickens were placed onto Mentofin treatment from date of placement. The other group was placed on Mentofin treatment once clinical signs of infectious coryza were detected.

It was established that the ongoing treatment with Mentofin significantly reduced the impact of infectious coryza. It was found that Mentofin treatment once clinical signs of IC were observed in the birds did show a reduction in clinical signs, there was no statistically significant difference from the untreated group. The mean disease score for the control group was found to be 0.400 (with a highest daily disease score of 1.21). The mean disease score for the group of birds which received treatment only once clinical signs were detected was 0.450 (with a highest of 0.96) while the group which received treatment from date of placement was 0.258 (with a maximum daily disease score of 0.56). It was demonstrated from this experiment that the ongoing treatment with Mentofin in the drinking water can significantly reduce the clinical signs of infectious coryza.