La enterotoxetemia, enfermedad nfecciosa más importante en crías de alpaca, es causante de altas tasas de mortalidad y se caracteriza por ocasionar brotes con muerte súbita sin permitir la aplicación de tratamientos convencionales. El control está supeditado a la aplicación de medidas preventivas de manejo y a la aplicación de inmunoprofilaxis. En e presente trabajo se ensayaron tres programas de vacunación anticlostridial durante las tres campañas de parición ( 2001, 2002 y 2003) en una Unidad de Producción de una Empresa de Propiedad Social del departamento de Puno. Se empleó un anacultivo a base de cepas del Clostridium perfringes predominantemente de origen ovino ( cepas A,B;C y D) más una cepa tipo A aislada de alpaca. El efecto de la vacuna se realizó comparando tasas de mortalidad total y asociada a enterotoxemia ocurrida antes de la introducción de la vacuna(año 2000) con los 3 años con programa de vacunación (años 2001, 2002 y 2003). El programa # 1 (año 2000) con los 3 años con programa de vacunación (años 2001, 2002, 2003). El programa #1 (año 2001) administró la vacuna al 100% de las madres gestantes (dos dosis).y al 100% de las crías (una dosis). El programa #2 (año 2002) vacun´solamente al 100% de las crías (dos dosis) y en el programa #3(año 2003) se procedió a vacunar solamente al 100% de las madres gestantes (una dosis). El efecto de la vacuna fue evaluado comparando los índices de mortalidad neonatal total y asociadas a enterotoxemia, básicamente relizando diagnóstico de campo. La aplicación de la vacuna redujo lamortalidad neonatal total progresivamente, desde 33.41% (año 2000), hasta alcanzar el 25.17% (año 2001), 23.72% (año 2002) y el 9.38 % (año 2003). La 19.45% (año 2000) hasta 7.18%, 9.1% y 0.98% para los años vacunados (2001, 2002 y 2003). Comparando los diferentes programas de vacunación, el análisis de diferencia estadística de proporciones determinó que el anacultivo (vacuna) fue de progrma aplicado. Sin embargo, la reducción fue más palpable en aquellos programas que involucraron vacunar madres gestantes. / Enterotoxemia, the most mportant infectious disease in alpacas juvenile, is the cause og high mortaly and to present outbreaks with suden death that does not allow the application of conventional treatments. Cntrol depends on preventive handlng measures and the application of inmunoprofilaxis. The present work applied three programs of anticlostridial vaccnation during three campaigns of birth (2001, 2002 and 2003) in a Social propriety Enterprise´s Unite ofProduction in Puno. We employed an anacultivo with strains of Clostridium perfringens predominantly of ovine origin and a strain type A isolated enterotoxemia Mortality that occurred before the introduction of the vaccine (year 2000) with the three years with program of vaccination ( years 2001, 2002 AND 2003). In program #1 (year 2001) the vaccine was administered to 100# of pregnant mothers( two juveniles were vaccinated (100%) (two doss) and n program #3 (year 2003) only pregnant mothers were vaccinated (100%) ( a dose vaccinated). The application of the vaccine equally reduced the tital neonatal mortality associated with enterotoxemia from 19,45% (year 2000) to 25.17 % (year 2001), 23.72% (year 2002) and 9.38% (year 2003). The vaccine equally reduced the mortality associated wirh enterotoxemia from 19.45%(year 2000) to 7.18% ,9,1% and 0,98% in the years in wich vaccination was given (2001, 2002and 2003). Comparng the different programs of vaccination, the anlysis of statistical difference of proportions detrmined that the anaculativo (vaccine) was wffective for the control of enterotoxemia in alpacas independently of the type of application program. Nevertheless, the reduction in mortality was greater in the programs that involved vaccinating pregnant mothers. / Tesis

Exposure to environmental conditions that impact organ growth and function and overall performance may increase poult susceptibility to poult enteritis complex (PEC). Temperature and hypoxic stress during embryonic incubation may impact organ growth and development, development of immunocompetency, post-hatch performance and may predispose poults to enteric disease. The objective of the first study was to provide a baseline of responses to incubation conditions so that further studies could be conducted on whether these stressors may increase susceptibility to post-hatch infection. Commercial Hybrid turkey eggs were incubated at standard (37.5°C) conditions from embryonic day (ED) 0 to ED24. At ED24, eggs were divided into thirds for incubation at 37.5°C, 36.0°C, or 39.0°C from ED24 until hatch at ED28. The objective of the second study was to evaluate the effects of incubation temperature conditions on intestinal development and susceptibility to challenge with turkey coronavirus (TCV). Commercial Hybrid eggs were incubated at standard (37.5°C) conditions from ED0 to ED24. At ED24, one-third continued incubation at 37.5°C, one-third were incubated at 36.0°C, and one-third were incubated at 39.0°C from ED24 until hatch at ED28. At d 5 (0 days postinfection, dpi) half of the poults were administered 0.1mL of TCV inoculum (3 x 103 EID50/0.1 mL). The third study examined the effects of incubation temperature conditions on intestinal development and susceptibility to dual challenge with both TCV and enteropathogenic E. coli. Commercial Hybrid eggs were incubated at standard (37.5°C) incubation conditions from ED0 to ED25. At ED25, eggs were randomized and half continued incubation at 37.5°C and half were incubated at 36.0°C from ED25 until hatch at ED28. At d 5 (0 dpi) half of the poults were administered 0.1 mL of TCV inoculum (4 x 103 EID50/0.1 mL) and 0.1 mL of E. coli (2.4 x 108 CFU/mL) by oral gavage. Main effects (P≤0.05) of incubation temperature and challenge, as well as twoway interactions (P≤0.05) of temperature and challenge were observed for the parameters evaluated in each study. These studies suggest an influence of incubation temperature conditions or PEC-associated pathogens on intestinal development and early post-hatch turkey poult performance. / Ph. D.

Necrotic enteritis in poultry is caused by Clostridium perfringens type A, and is estimated to cost the worldwide poultry industry approximately $2 billion dollars a year, due to increased mortality and decreased feed conversion and weight gain. Very little is known about the pathogenesis of this disease due to the lack of a consistently reproducible experimental model. This dissertation outlines the development of an effective and consistent experimental model for necrotic enteritis in broiler chickens. It was also found that in vivo passage through the chicken's intestinal tract let to increased virulence; we increased the proportion of birds developing disease from 34.6% to 81.4%. Researchers have proposed that alpha toxin (CPA) is believed to be the critical virulence factor of the disease. All type A isolates have the potential to produce CPA, thus we challenged birds with numerous type A isolates that are virulent in other animal hosts. However, we found that they did not produce necrotic enteritis in broiler chickens. In addition, challenge with culture supernatant alone failed to produce gross lesions in the birds, although challenging with washed whole cell cultures did do so. Vaccinating birds with HIS-tagged recombinant CPA provided partial protection against disease; there was a 42.0% decrease in lesion development. The conclusion of this doctoral research is that CPA does have a role in the pathogenesis of necrotic enteritis in broiler chickens, but there are apparently other critical virulence factors involved in the development of disease.

No description available.

Call number: LD2668 .T4 1957 S55 / Master of Science

Thesis (Ph. D.)--University of Adelaide, 1984. / Some ill. mounted. Includes bibliographical references (leaves 109-129).

Ulm, Univ. Diss., 2006.

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (p. 234-252) Also available in print.

Proefschrift Universiteit van Amsterdam. / Met een samenvatting in het Nederlands.

Call number: LD2668 .T4 1984 L33 / Master of Science