By 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."