Epidemiological aspects of the use of live anticoccidial vaccines for chickens

Williams, R. B.

doi:10.1016/s0020-7519(98)00066-6

Cited by 201 publications

(150 citation statements)

References 16 publications

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“…It is notable that the litter oocyst concentrations for birds treated with anticoccidial drugs were much lower than those for vaccinated birds (Figure 1). This was a reversal of the usual situation (Williams, 1992b(Williams, , 1998Shirley et al, 1995;Williams et al, 1999), although it has sometimes been observed before (Shirley et al, 1995;Williams et al, 1999). It may indicate either that the field challenge on the anticoccidial drugtreated farm was very low, or that the resident coccidia were more sensitive than usual to the anticoccidial drugs used there.…”

Section: Discussionmentioning

confidence: 84%

“…This 'shoulder' coincided exactly with the period of highest oocyst accumulation in the litter of the anticoccidial drug-treated birds. Although the patterns are not typical of what is generally observed in Paracox-vaccinated and anticoccidial drug-treated birds (Williams, 1992b(Williams, , 1998, they may be regarded as variants of the usual patterns, considering the wide variations in oocyst counts that might be encountered (Shirley et al, 1995;Williams et al, 1999). It is clear, for instance, that the first oocysts seen in vaccinated flocks appeared 13 to 20 days earlier than those first to be seen in the anticoccidial drug-treated birds, indicating that the faster developing precocious lines contributed to at least the earlier portion of the peak in vaccinated birds.…”

Section: Discussionmentioning

confidence: 85%

“…These differences might affect the efficacies of anticoccidial vaccine or drug treatments. As the trials reported in this work were carried out in a relatively dry climate, the effect this may have had on litter moisture might have influenced both natural coccidial challenge and the re-infection cycle of vaccinal coccidia (Williams, 1998). Broilers in Italy are fed maize-based, rather than wheat-based, diets as in many other European countries, and it is known that feeding maize reduces the pathogenicity of coccidial infections compared with feeding wheat (Williams, 1992a).…”

Section: Introductionmentioning

confidence: 99%

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Comparison of an attenuated anticoccidial vaccine and an anticoccidial drug programme in commercial broiler chickens in Italy

Williams¹,

Gobbi²

2002

Avian Pathology

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A live attenuated anticoccidial vaccine (Paracox) was compared with a nicarbazin-monensin anticoccidial drug shuttle programme in three crops of Italian broilers, comprising a total of 290 405 chickens. All birds received the antibiotic growth promoter avilamycin. No coccidiosis was evident during the trials, but the occurrence of oocysts in the litter demonstrated that a natural challenge was present. Vaccinated birds consistently performed at least as well as those treated with the anticoccidial drug shuttle. The final mean weights of vaccinated birds were significantly greater (P < 0.001) than those of birds treated with anticoccidial drugs, both for females at 36/37 days and males at 56 days. Feed conversion ratios, total mortality including culls, the proportion of rejects at the processing plant, and the moisture content of the litter were not significantly different between the two control methods. Growth curves showed that there was no post-vaccinal growth check in the vaccinated birds and no intolerance of the anticoccidial drug treatment. There was no overall seasonal effect, regardless of treatment, on the performance of the three crops reared from November 1997 to July 1998. These findings suggest that the use of this vaccine is likely to enable the replacement of anticoccidial drug shuttle programmes in broilers reared under conditions similar to those used in these Italian flocks.

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Section: Discussionmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

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Comparison of an attenuated anticoccidial vaccine and an anticoccidial drug programme in commercial broiler chickens in Italy

Williams¹,

Gobbi²

2002

Avian Pathology

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“…The pathogenicity ranges from moderate to severe. Although E. praecox and E. mitis are considered non pathogenic, experimental infections with these species may produce pathogenesis resulting in enteritis, diarrhoea, and reduced feed efficiencies (Williams 1998), which warrants their inclusion in the list of coccidia to be controlled. Generally, the five most pathogenic species can be differentiated in the host on the basis of clinical signs, characteristic tissue lesions, prepatent period, size of oocysts, and morphology of intracellular stages.…”

Section: Diagnosis and Identification At Species Levelmentioning

confidence: 99%

Control of poultry coccidiosis: changing trends

Tewari

Maharana

2011

J Parasit Dis

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Coccidiosis is the most important protozoan disease affecting the poultry industry worldwide. Control of poultry coccidiosis is presently based on managerial skills and the use of prophylactic coccidiostatic drugs. With the emergence of drug resistant Eimeria strains, emphasis has been laid on development and use of safer vaccines; some of them have been commercialized successfully. The present review deals with the various factors responsible for the development of clinical coccidiosis in poultry as well as an overview of the currently available inducers and boosters of immunity against coccidiosis. There are three groups of vaccines currently available against coccidiosis which can be distinguished on the basis of characteristics of the Eimeria species included in the respective products, viz. vaccines based on live virulent strains, vaccines based on live attenuated strains, and vaccines based on live strains that are relatively tolerant to the ionophore compounds. The latter vaccine combines the early chemotherapeutic effect of ionophores with the late prophylactic effect of vaccination. Although in the near future more varieties of oocyst based live vaccines are expected, identification of selective coccidian-specific immunoprotective molecules is likely to get more attention to facilitate the sustainable control of poultry coccidiosis.

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“…The annual worldwide losses due to coccidiosis exceed two billion Euros for prophylaxis and medication [1]. Additional economic losses include mortality, morbidity, and poor feed conversion of birds that survive out breaks [2]. Eimeria, an intracellular protozoan parasite belongs to the Phylum Apicomplexa, is the causative agent of coccidiosis.…”

Section: Introductionmentioning

confidence: 99%

Eimeria Spp.Infection in Some Broiler Farms in Khartoum State, Sudan

Abdelnabi¹

2017

SOJVS

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A cross sectional study was conducted during October 2013 to February 2014 to identify and determine the prevalence of Eimeria spp. among broiler chickens reared in open and closed systems in Khartoum, Khartoum North, and Omdurman, Khartoum State, Sudan. A total of 90 broiler intestines were collected from slaughtered broilers at slaughterhouse or farms and examined by direct smear and standard floatation test to detect Eimeria species. The overall prevalence of Eimeria spp. was 5.5 % of the examined samples. Two Eimeria species were identified viz, Eimeria tenella and Eimeria acervulina. E. tenella was the dominant species with an infection rate of 5.5 % followed by E. acervulina 2.2 %. The prevalence of Eimeria spp. in open and closed systems was 4.4 % and 6.7 %, respectively. The overall prevalence of Eimeria spp. was 10 %, 6.7 % and 0 % in Khartoum, Khartoum North and Omdurman, respectively. No significant associations (P ˃ 0.05) were observed between different locations and management systems employed of the examined chickens. Further epidemiological studies should be conducted to determine the prevalence and identify Eimeria spp. in all states of the Sudan.

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Epidemiological aspects of the use of live anticoccidial vaccines for chickens

Cited by 201 publications

References 16 publications

Comparison of an attenuated anticoccidial vaccine and an anticoccidial drug programme in commercial broiler chickens in Italy

Comparison of an attenuated anticoccidial vaccine and an anticoccidial drug programme in commercial broiler chickens in Italy

Control of poultry coccidiosis: changing trends

Eimeria Spp.Infection in Some Broiler Farms in Khartoum State, Sudan

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