Detection of Mycoplasma capricolum subsp. capripneumoniae and Mannheimia haemolytica as causative agents of pleuropneumonia in goats / Detección de Mycoplasma capricolum subsp. capripneumoniae y Mannheimia haemolytica como agentes causales de pleuro-neumonia en cabras

Abstract Objective: The aim of the study was detection of two major causative agents of pleuropneumonia, Mycoplasma capricolum subsp. capripneumoniae (Mccp) and Mannheimia haemolytica, in goats. To the best of our knowledge, this study is the first investigation of Mccp in Iran. Methods: 50 grossly suspected lungs to pleuropneumonia and 10 healthy samples were collected from Shiraz abattoir. Results: Histopathological evaluation of tissue samples showed various diagnosed pneumonias including 40% bronchointerstitial pneumonia (20 samples), 34% interstitial pneumonia (17 samples), 10% fibrinopurulent bronchopneumonia (5 samples), 12% purulent bronchopneumonia (6 samples) and 4% chronic pneumonia (2 samples). In molecular study, all 50 suspected samples and 10 healthy ones by PCR showed no Mccp positive sample, but the detection rate of M. haemolytica in suspected samples was 14% and in healthy lungs was zero. Conclusions: It may be concluded that goats referred to Shiraz abattoir is free of Mccp. Further sampling and molecular testing at the level of suspected herds to CCPP can be useful.

Resumen Objetivo: El objetivo del estudio fue la detección de dos agentes causantes principales de pleuroneumonía, Mycoplasma capricolum subsp. Capripneumoniae (Mccp) y Mannheimia haemolytica, en cabras. Hasta donde sabemos, este estudio es la primera investigación de Mccp en Irán. Métodos: 50 pulmones muy sospechosos de pleuroneumonía y 10 muestras sanas se obtuvieron del matadero de Shiraz. Resultados: La evaluación histopatológica de muestras de tejido mostró varias neumonías diagnosticadas, incluyendo 40% de neumonía broncointersticial (20 muestras), 34% de neumonía intersticial (17 muestras), 10% de bronconeumonía fibrinopurulenta (5 muestras), 12% de bronconeumonía purulenta (6 muestras) y 4% neumonía crónica (2 muestras). En un estudio molecular, las 50 muestras sospechosas y 10 sanas por PCR no mostraron una muestra positiva de Mccp, pero la tasa de detección de M. haemolytica en muestras sospechosas fue del 14% y en pulmones sanos fue cero. Conclusiones: se puede concluir que las cabras referidas al matadero Shiraz están libres de Mccp. La realización de muestreo adicional y pruebas moleculares a nivel de rebaños sospechosos para CCPP puede ser útil.

Assessment of immunity against avian colibacillosis induced by an aroA mutant containing increased serum survival gene in broilers

Colibacillosis is an important disease in the poultry industry which causes serious economic damages. As it is suggested that vaccination is one of the means to control colibacillosis, we tried to investigate the vaccine potential of a ÃaroA derivative of an O78:K80 avian pathogenic Escherichia coli containing increased serum survival gene. 490 chicks were selected as follows: For assessment of virulence of ÃaroA mutant, 30 chicks were divided into three groups and injected with 0.5ml of PBS or bacterial suspension containing either10(7)colony forming units (CFU) of mutant or parent strains via subcutaneous route. Macroscopic lesions and mortality rate were recorded in different groups during the week after challenge. For assessment of safety and immunogenicity of the ÃaroA mutant, three groups of 20 chicks were vaccinated by aerosol administration of 250 ml of suspension containing 10(8) CFU of mutant strain at days 1 and 14, while the two other groups received PBS or wild type strain. Macroscopic lesions and mortality rate were recorded in different groups until day 21. To determine whether the vaccination is protective against challenges or not, the chickens were vaccinated at days 1 and 14 and challenged intramuscularly with either a homologous or heterologous strains at day 21. Macroscopic lesions and mortality rate were recorded in different groups during the week after challenge. The results revealed that the ÃaroA mutant was slightly virulent, however it was safe and did not cause mortality, lesions or weight loss after vaccination. Antibody responses were similar in the control and mutant groups and vaccination did not induce a significant humoral immunity. The mutant could not protect chickens against both homologous and heterologous challenges. This could be due to several factors such as the high amount of maternal antibodies in the first two weeks of life, and the vaccination procedure.