Abstract
Avian coccidiosis is a disease of great economic importance in poultry production which is resulted from infection by protozoa of the genus Eimeria. An epidemiological study of chicken-coccidiosis was conducted in Savar, Manikganj, Sylhet, Joypurhat and Cox's Bazar areas of Bangladesh. Studies were also done to develop alternative method of treatment and/or control of chicken-coccidiosis instead of commonly prevailed. A total of eight experiments were conducted during the period of 2004 to 2007. Epidemiological data were collected from five different agro ecological zones and coccidiosis was found as one of the major chicken diseases. Poor hygienic management along with development of drug resistant enhanced the infection rate. The disease had been found to be more prevalent during winter. A large number of farmers reported failure to have satisfactory results after using available drugs for the treatment of chicken-coccidiosis. A high infection rate in broiler chicks was observed at the age of 3 weeks (48%) whereas in layer flock it was after 5 weeks (57%). E. acervulina (43%) and E. tenella (33%) were the most common coccidian species in Bangladesh. Oocysts were first detected in litter mostly at second week and the number gradually increased and reached a peak at 5th to 6th week of birds' age. Clinical signs from E. tenella infection were observed mostly at 4 to 6 day post infection. E. tenella isolates were collected from the field cases of clinical caecal coccidiosis from some areas of Bangladesh and were selected to develop an experimental infection. Gazipur (GC-2/06) isolates were found to be more pathogenic than Savar (SC-1/05) isolates followed by Mymensingh (MC-3/06) isolates. In order to develop alternative method of therapy four indigenous herbs were tested for the treatment of chicken-coccidiosis. Neem (Azadirachta indica) seed and leaf and Korola (Momordica charantia) along with good hygienic management were found to be effective against coccidiosis. In in-vitro study, 20% concentration of Water pepper (Polygonum hydropiper) and Neem leaf extract were found to be effective in inhibiting the sporulation of coccidian oocysts. In on-farm trial, 20% concentration of Water pepper and Neem leaf when mixed with rice husk litter reduced oocysts concentration to a considerable level. Wire-floored metallic cage rearing system was found to be highly effective in controlling chicken-coccidiosis followed by Slate rearing system. Most of the infection was observed in deep litter rearing system during this study. The strains of Eimeria spp. in poultry rich areas of Bangladesh were found to develop a degree of resistance against commonly used sulphonamides. This study indicated that weekly examination of litter oocysts could give an early forecast about coccidian infection and the use of Neem leaf and seed and Korola for treatment could reduce the infection rate to a greater extent. Wire-floored metallic cage rearing system could reduce the coccidial infection up to 100% and that was a farmers-friendly control measure of coccidia.