Studies on Sensitivity of Eimeria Isolates from Chickens to Some Anticoccidial Drugs

Abstract

Among various parasitic infections, coccidiosis caused by obligate intracellular protozoan parasite of the genus Eimeria is the major constraint for modem poultry production.

It remains one of the most expensive and common diseases of poultry universally (Stevens, 1998; Dalloul and Lillehoj, 2006) where E. acervulina, E. brunetti, E. maxima, E. mitis, E. necatrix, E. praecox, and E. tenella are considered as the pathogenic species (McDougald, 2003), infecting primarily the intestine of the susceptible hosts of intensively reared livestock causing the economic losses that are due to high morbidity (due to acute, bloody enteritis) and mortality rates, malabsorption, ineffecient feed utilization and impaired growth rate in broilers as well as a temporary reduction of egg production in layers (Dalloul et al., 2005), in addition to the use of anticoccidial drugs and/or vaccines for treatment and prevention.

Control of coccidiosis has been a problem for poultry producers since the time chickens were first placed in moderate sized groups (Long and Jeffers, 1986).

In addition, subclinical coccidial infection occures, often undetected and may have a remarkable influence on the weight gain and feed conversion ratio (Voeten, 1971; Braunius, 1980a, b).

Inspite of advances in immunological, biotechnicological and genetical methods, control of coccidiosis chiefly depends upon prophylactic chemotherapy with anticoccidial drugs (McDougald and