DNA sequence polymorphisms in two strains of Fasciola hepatica from Egypt and Europe.

A new PCR based system was used that had broad detection capability among parasites based on a conserved region of the 18 S ribosomal DNA gene. Five samples each of European and Egyptian Fasciola hepatica of bovine origin were obtained and DNA was isolated. The target of the PCR primers was a fragment of approximately 600 nucleotides in length corresponding to a region of the 18 S rRNA gene. Sequences were compared over a 107 base pair region that identified polymorphism between the strains. All five Egyptian isolates were identical. Likewise all of the European isolates had identical sequence. There were polymorphisms between the two strains and also with F. hepatica isolates from North America. Both the European and Egyptian isolates have a single base addition in the polymorphic region. In addition there is a single base substitution in the Egyptian isolates when compared to the others. This region is a small target that can be used to identify the origins of different F. hepatica isolates.

Parasitological effects of simultaneous infections induced by Schistosoma mansoni and aflatoxin B1 in Syrian golden hamsters.

To determine the effect of S. mansoni and aflatoxin B1, 120 hamsters were divided into six groups of 20 each as follows: group I, S. mansoni only, group II, aflatoxin B1 only, group III, S. mansoni then aflatoxin B1 eight week, group IV, aflatoxin B1 then infected with S. mansoni six weeks, later, group V, aflatoxin B1 and S. mansoni simultaneously, group VI control. Loss of body, liver, and spleen weight was more prominent in groups IV and V than in other four groups. The higher mortality rate was in group III. Animals treated with aflatoxin followed by S. mansoni infection appeared to have a less deteriorating effect on the liver (group IV) than group III treated with by S. mansoni first followed by aflatoxin treatment. No morphological abnormalities were detected in the worms including testicular changes in males but a significant number of females was immature even in copula (P < 0.01) in groups III, IV, and V. The average number of S. mansoni eggs was less in groups III, IV, and V in comparison to group I. No abnormalities were detected in the eggs for groups infected with S. mansoni. The diameters of granulomas around eggs, were large on an average in groups III, IV and V as compared with groups I and II.

The immunogenic effect of purified antigens of B. alexandrina against S. mansoni in experimental animals (II) as measured by the histopathological changes in the liver.

It can be safely said that up till now, no method of vaccination (including recent genes encoding vaccines) has yet proved to be totally effective since they gave partial and low levels of protection against S. mansoni infection. The objective of this work is to try testing the immunogenic effect of two purified non infected B. alexandrina hepatopancreas through histopathological changes in liver of Swiss albino mice (15-20 gm). Gel filtration chromatography was used to fractionate the crude antigen into five fractions followed by re-fractionation and determination of their molecular weights by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Four dilutions of Fiv (20000-29000 daltons) and Fv (20000-24000 daltons) were injected in two groups of mice (33 each) at weekly intervals and another control group was injected with phosphate buffer saline (PBS) in the same manner. Sacrification was done seven weeks from infection with 100 S. mansoni cercariae through immersion method. The results revealed that there is marked histopathological changes in liver of the control group in comparison to the two vaccinated groups which appear more or less normal with slight inflammatory infiltrate.