COCCIDIOSIS.*

                                               BY

                     W. R. KERR, M.R.C.V.S., D.V.S.M.,

         Lecturer in Veterinary Science, Harper Adams College.

(Reprinted from the Harper Adams Utility Poultry Journal, Volume XV, No. 11.)

         Coccidiosis, as a disease of poultry, is becoming a menace to the industry, a
disease which may cause serious losses in chicken rearing. Second only in import-
ance to B. W. D., though it is not so readily disseminated, there is not the same
possibility of elimination as in the latter disease. The seriousness of the problem
has to be realized, and reasonable means of control and treatment instituted to
safeguard poultry husbandry.

                                             CAUSE.

         This is primarily a disease affecting the young of members of the bird family,
and also many of the animals—cattle, sheep, rabbits, goats, etc.—and is caused by
a small parasite Eimeria (Coccidium). It is observed in all species of the domes-
tic fowl, pheasants and grouse. Usually in each a different name is given, but
according to Hutyra and Mank it is probably only a different variety of Eimeria
Avium.

         The droppings of affected chicks may contain millions of "oöcysts" as the
parasite is named at this stage. The transmission of the disease is chiefly by
water and food-stuff contaminated by the droppings, whilst other means of
spreading are by workers' boots, adult carriers, contaminated range, and also the
egg shell is stated to be a source of infection. The parasite is very resistant, and
can live in the soil of a hen run for at least a period of twelve months.

                                    LIFE HISTORY.

         The oöcyst, which is very minute, is approximately 1/700 ins. in size, and
resembles a miniature egg in that it possesses a resistant shell containing a fluid,
the white, in which floats a part similar to the yolk. In the presence of moisture
and warmth an important phase takes place at this stage, before it can become
infective to chicks, and that is, the yolk part has to develop or sporulate into
four small elements. This takes at least 48 hours. The sporulated oöcyst is

*Paper read at the XIVth Annual Poultry Conference at H. A. A. C., September 1930.

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