Limited heterogeneity between strains of Eimeria tenella isolated from Britain and Bangladesh

Protein profiles of five avian Eimeria species

SDS-PAGE fingerprint studies of oocyst antigens of five major Eimeria species including E. acervulina, E. maxima, E. necatrix, E. praecox and E. tenella demonstrated that their protein patterns are different, but there are some shared proteins between species and at least one protein band (45 kDa) was conserved among the five species. In Western blot studies, some species-specific as well as a few shared immunogenic bands were identified and chicken anti-E.maxima sera reacted with the conserved protein band in oocyst antigens of all these species.

Anticoccidial vaccines for broiler chickens: pathways to success

The use of live vaccines, either attenuated or non-attenuated, for the control of coccidiosis due to Eimeria infections in broiler breeder or layer chickens is well established. Use in broilers, however, has been slow to gain acceptance. This has been partly for economic reasons, but also because of perceived adverse effects on early chick growth, particularly with non-attenuated vaccines, and concerns about timely onset of protective immunity in such short-lived birds. This review describes advances in understanding of epidemiological factors and recent improvements of administration methods that have helped to allay these fears and to make the use of anticoccidial vaccines in broilers technically achievable. Topics discussed include: (1) types of commercially available vaccine, (2) vaccines in development, (3) vaccination methods and equipment, (4) basis of vaccine efficacy and immunogenic variation of parasites, (5) key factors in the survival, sporulation and dissemination of vaccinal oocysts, (6) descriptions and significance of patterns of litter oocyst accumulation and occurrence of intestinal lesions in vaccinated flocks, (7) rotation of anticoccidial vaccination and chemotherapy to restore drug sensitivity to resistant wild-type coccidia, (8) combinations of anticoccidial vaccination and chemotherapy, (9) interactions between coccidiosis and clostridiosis in broilers and compatibilities of potential control methods, (10) published performance data for live anticoccidial vaccines in broilers, (11) possible further developments of live vaccines.

Isoenzyme activities of different strains of Cryptosporidium parvum

Different isoenzyme activities have been assayed in three strains of Cryptosporidium parvum, C1 (C. parvum from infected calves, UK), C2 (C. parvum from infected calves, Egypt) and C3 (C. parvum from infected goats, Egypt). The electrophoretic variations of five enzymes; lactate dehydrogenase (LDH), glucose phosphate isomerase (GPI), hexokinase (HK), malate dehydrogenase (MDH) and glutamate dehydrogenase (GLDH) were compared among the three different isolates using native polyacrylamide gel-electrophoresis. LDH showed an identical pattern in the three isolates. GPI showed two different bands in C3 and C1, with both bands present in C2. HK activity showed a weak band in C1 but no reaction was detected with C2 and C3. Malate dehydrogenase (MDH) showed no reaction in C1, but similar bands in C2 and C3. Glutamate dehydrogenase (GLDH) showed two different patterns, C2 and C3 had one pattern and C1 showed additional zones of reaction. Rat liver homogenate was run at the same time as the parasite extracts as a positive control. This investigation suggests that GPI, HK and GLDH could be used to characterise different Cryptosporidium isolates.

Eimeria spp. of the domestic fowl: analysis of genetic variability between species and strains using DNA polymorphisms amplified by arbitrary primers and denaturing gradient-gel electrophoresis

The genetic relatedness of 5 Eimeria spp. of the domestic fowl, including 11 strains of E. acervulina, 2 strains of E. tenella and 1 precocious line of E. acervulina, was assayed by means of random amplified polymorphic DNA (RAPD) and denaturing gradient-gel electrophoresis (DGGE). Seven different oligonucleotides were used to generate similarity coefficients for the species and strains of Eimeria infecting chickens. Between 1 and 13 DNA segments, depending on the species/strain-primer combination, were amplified with the various primers. Amplification products ranged in size from 0.16 to 3.8 kb. E. acervulina strains demonstrated two to four major common bands unique to the species. These strains also exhibited major and minor differences in their DNA patterns. Band-match analyses from both polyacrylamide and denaturing gradient gels were used to calculate similarity coefficients for the Eimeria spp. and strains tested. Species differences, readily detected upon examination of DNA banding patterns, gave similarity coefficients of 4%-38% and 3%-18% when analyzed by polyacrylamide- and denaturing gradient-gel electrophoresis, respectively. A similar analysis of E. acervulina strains, yielded similarity coefficients of 55%-95% and 51%-85%, respectively. The differences observed between both species and strains were greater when the RAPD-assay products were analyzed via DGGE, indicating that a combination of these two techniques may provide a more stringent analysis of the genetic relatedness of these coccidia.