Studies on vaccination against infectious laryngotracheitis by the drinking water

The authors, after a brief reference to the wide use in the field of a mild vaccinal strain of infectious laryngotracheitis virus by the drinking water to prevent the disease, describe laboratory experiments to confirm the efficacy of this route of administration compared with the conventional one (ocular). Four groups of 7-week-old chickens were vaccinated as follows: a) ocularly with the normal dose, b)by instillation per os, c) by the drinking water with one dose, d) by the same route with ten doses; a fifth group was left as negative control. To compare the effect of vaccination by the above different methods of administration the serum-neutralization test was used. The results obtained are finally discussed.