Comparison of Recovery of Schistosomula of Schistosoma japonicum from Lungs of Mice and Rats

Abstract

Various strains of mice and rats were exposed to small doses of Schistosoma japonicum cercariae. At intervals, they were challenged with 200 to 230 cercariae per mouse and 500 to 520 cercariae per rat. Age-matched control animals received only the challenge infection from the same pool of cercariae. Recoveries of schistosomula from experimental and control groups were different on day 3 through day 5, with peak recovery on day 3 or 4 in four strains of mice examined (DBA/2, C57BL/6, C3H/He, and SWM) as well as in Fischer rats, indicating rapid migration of S. japonicum to the lung compared with that of S. mansoni. Significant reductions of recovery of schistosomula from lungs were demonstrated in DBA/2, C3H/He, SWM, and B10.S mice at week 3, but not in BALB/c, CBA, and C57BL/6 mice. Significant reductions were also demonstrated in Donryu, Wistar, Sprague-Dawley and Fischer rats at week 6. The degree of reduction depended on cercarial doses used for the initial exposure. Studies in DBA/2 mice revealed that the degree of reduction intensified biphasically, being greatest at week 5 and at week 12. The lowest recovery was demonstrated at week 6 in Fischer rats, when recovery of schistosomula tentatively increased in DBA/2 mice. A good correlation was found between recovery of schistosomula from lungs and recovery of adults by portal perfusion when DBA/2 and C57BL/6 mice, and Fischer rats were used for comparison. Thus, the present results provide basic information on the lung recovery of schistosomula of S. japonicum in suitable and unsuitable hosts.

Characterisation of a secretory serine protease inhibitor (SjB6) from Schistosoma japonicum

“…Rats (N = 3) and mice (N = 5) were infected percutaneously with 200 and 60  S. japonicum cercariae, respectively, using the cover slip method. Blood samples were collected from mice prior to infection and 6 weeks post-challenge while in the rat time-course experiment, blood samples were collected after a primary and a secondary cercarial challenge (as above) based on the observation that immune resistance in rats re-challenged with schistosomes was shown to be highest between 4–8 weeks after re-infection [45,46]. Blood was collected via the tail vein (rats), the tail tip (mice) or from cardiac puncture at necropsy.…”

Specific humoral response of hosts with variable schistosomiasis susceptibility

“…Notably, sections of rat lung contained schistosome larval stages nine days after a secondary cercarial challenge (). It could not be determined if these parasites were under immune attack but the lung is recognized as an important site for the elimination of schistosomes 9 , 17 , 19 , 28 …”

“…After this group I was terminated while groups I 5 and I 9 were challenged with 350 cercariae per rat and terminated 5 and 9 days later, respectively. The time points in TC1 were based on observations that immune resistance in the rat has been shown to be highest between 4 and 8 weeks after re‐infection 19 , 60 . The time points in TC2 were selected to capture the local tissue response after schistosome larval migration through the skin and lung after the first and fourth day post infection, respectively, 19 and after allowing a further 5 days for an optimal LN response 26 , 27 , 63 .…”

Schistosoma haematobium , S. intercalatum , S. japonicum , S. mansoni , and S. rodhaini in mice: relationship between patterns of lung migration by schistosomula and perfusion recovery of adult worms

“…Reports available for S. japonicum show that this species arrives earlier in the lungs, yields peak recoveries from minced lung tissues on day 3 p.i. (Gui et al 1995) or shortly thereafter (Usawattanakul et al 1982;Moloney and Webbe 1983), and disappears rapidly from this organ. With respect to S. haematobium we are aware only of the work of Georgi et al (1986), who detected schistosomula by autoradiography in the lungs for the ®rst time on days 7±8 p.i.…”