[author: Donald Zuhn]

Last month, the U.S. Patent and Trademark Office issued U.S. Patent No. 8,293,266, entitled "Paromomycin-supplemented feed stuff for turkey and use thereof for prophylaxis of histomoniasis, reduction of the horizontal spreading of histomoniasis, and for improved weight gain and feed conversion," to Huvepharma AD, a pharmaceutical company based in Sofia, Bulgaria.  The '266 patent is directed to a method of preventing the infection with or spread of histomoniasis or increasing weight gain in turkeys using a feed supplemented with paromomycin.

Histomoniasis (or blackhead disease) is a disease of poultry species, particularly chickens and turkeys, due to parasitic infection by a protozoan, Histomonas meleagridis.  The parasite specifically infects the cecum and liver of birds, with symptoms of the infection including depression, reduced appetite, poor growth, increased thirst, sulphur-yellow diarrhoea, listlessness, and dry, ruffled feathers.  Paromomycin (left), also known as monomycin and aminosidine, is an aminoglycoside antibiotic that was first isolated from Streptomyces krestomuceticus in the 1950s.  It is structurally related to neomycin, streptomycin, and kanamycin and has a broad spectrum of activity, including activity against protozoa, bacteria, and cestodes.  Surprisingly, the inventors found that the continuous application of paromomycin in feed in dosages below 1000 ppm, in the range 10-750 ppm, had a significant effect in:  (i) reducing the mortality of infected birds, (ii) significantly reducing the horizontal spread of the disease from infected to healthy birds, and (iii) improving the growth performance of the infected and non-infected animals.

The '226 patent issued on October 23, 2012 from U.S. Application No. 09/967,726, which was a U.S. national stage application of International Application No. PCT/BG2008/000003, which claims priority to Bulgaria Patent Application No. 109831.  Independent claims 1, 4, and 6 of the '226 patent recite:

1.  A method for preventing infection with or spread of histomoniasis in healthy turkey or in a flock of healthy turkey, the method comprising: formulating a feed stuff for turkey comprising feed supplemented with paromomycin in an amount sufficient to provide prophylaxis of histomoniasis; and feeding the feed stuff to the healthy turkey or flock of healthy turkey continuously from day 0 until slaughter or at least for more than one week; whereby infection or spread of histomoniasis in the healthy turkey or in the flock of healthy turkey is prevented.

4.  A method for reducing or preventing horizontal spread of histomoniasis in a flock of turkey, the method comprising: formulating a feed stuff for turkey comprising feed supplemented with paromomycin in an amount sufficient to provide prophylaxis of histomoniasis; and feeding the feed stuff to the flock of turkey continuously from day 0 until slaughter or at least for more than one week; whereby horizontal spread of histomoniasis is reduced or prevented in the flock of turkey.

6.  A method for increasing weight gain and improving feed efficiency in turkey or in a flock of turkey, the method comprising: formulating a feed stuff for turkey comprising feed supplemented with paromomycin in an amount sufficient to provide prophylaxis of histomoniasis; and feeding the feed stuff to the turkey or to the flock of turkey continuously from day 0 until slaughter or at least for more than one week; whereby weight gain is increased and feed efficiency is improved in the turkey or the flock of turkey.

Independent claims 8, 11, and 13 are identical to the above claims with the exception that the term "formulating" is replaced with "providing."