Respiratory Mycoplasma Infection in Chickens in Nsukka Agro-Ecological Zone, Enugu State, Nigeria

The occurrence, antibacterial susceptibility profile and pathogenic potentials of respiratory mycoplasmas in chickens in Nsukka Agro-ecological zone were evaluated. Mycoplasmas were isolated from 12(3.8%) of the 312 chickens sampled.3 (20%) of the farms were positive for mycoplasmas and were all located in Nsukka LGA. Out of 12 mycoplasmas isolated, 7(58%) were Mycoplasma species, while 5 (42%) were Ureaplasma species. The Mycoplasma species were isolated from clinically healthy birds while the Ureaplasma species were from birds with respiratory signs. Ten (83.3%) of the isolates belonged to glucose-positive arginine-negative group while 2 (16.7%) belonged to glucose-negative arginine-negative group. Four (33.3%) of the isolates were sensitive to erythromycin, while 5 (41.7%), 9 (75%), 11 (91.7%), 11 (91.7%) were sensitive to streptomicin, gentamicin, tetracycline and ciprofloxacin respectively. Experimental infection was established and mycoplasmas were re-isolated from all infected groups. No clinical signs were observed in any of the infected birds. Oxytetracycline treated birds remained infected throughout the duration of experiment. Infection in the Tylosindoxycycline and tylosin (pure) treated groups was eliminated by days 6 and 3 post treatment respectively. This study has demonstrated that chickens, especially layers, in Nsukka agroecological zone harbour mycoplasmas that are highly sensitive to tylosin.