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Pollen/spore assemblages represented in surface soils, supporting a range of different vegetational community types and from various localities within Queensland, Australia, were analysed. To test the variability within surface soils from individual locations, replicate samples were taken and shown to contain similar pollen/spore assemblages. Seasonal samplings provided varying frequencies of particular pollen/spore types that were sometimes correlated with flowering of corresponding parent plant taxa. Sampling from a range of communities revealed that pollen/spore types discriminated vegetational communities. Results indicated that specific palynomorph types may be utilized as indicators of the communities within which they were found. Chenopod pollen types were found to reflect drier habitats while higher frequencies of fern and moss spores indicated more humid habitats. Fungal spores were found to also discriminate between community types. Carbon isotope signatures of some vegetational community types resulted in less negative ratios for C 4 plant-dominated communities and more negative ratios for C 3 plant-dominated communities. Ratios were also more negative for communities with greater water availability. Thus, palynology combined with carbon isotope analyses is shown to be potentially useful in forensic science in Queensland through soil sample comparisons between soil-bearing items associated with an investigation, and soils associated with the vegetation at the scene of the crime. It is suggested a database of pollen/spore types be initiated as a reference collection to be utilised for expert witness evidence in this field.

A paper radioimmunosorbent test (PRIST) was shown to be sensitive and reproducible when used with excretory/secretory antigen of Toxocara canis second stage larvae. Whatman No. 50 filter paper (5 mm discs) gave the most consistent and clear results with antigen at a concentration of 100 micrograms/ml, and could be stored for up to 3 weeks in vacuo at -70 degrees C. Antigen coated discs were incubated with test sera at 1:10 dilution for 3 h at room temperature (21 degrees C), reacted with [125I]anti-human IgG for 1 h and counts determined in a gamma counter. Sera from patients with fascioliasis, taeniasis, schistosomiasis, oxyuriasis, trichinellosis and ancyclostomiasis gave counts similar to cord serum controls. Sera from patients with ascariasis gave counts of up to twice as great as controls, but sera from patients with toxicariasis produced counts of 7,000-13,000, a 4-6-fold increase.

In uninfected mice, the percentage of IgA-containing cells labelled one day after a single injection of tritiated thymidine ([3H] d Thd) was constant in the upper, middle and lower small intestine. In uninfected mice receiving an additional injection on the two preceding days there was about a threefold increase after the three injections indicating accumulation of labelled cells during the three day period. Five days after infection with Trichinella spiralis, the percentage of IgA cells labelled after a single injection of (3H)d Thd was increased at each site indicating increased division and, or, localisation of IgA cell precursors in the intestine. The numbers of cells labelled after three injections were reduced at this time, with no evidence of accumulation of further cells labelled from the two additional injections on previous days. By nine, 13 and 18 days after infection the numbers of IgA cells labelled after both single and triple injections were each increased, indicating increased division and, or, localisation of IgA precursors in the intestine with accumulation of labelled cells over the three day period resembling that in uninfected mice.

SUMMARYSeven different flotation fluids were assessed for their efficiency in recovering Toxocara canis ova from artificially seeded soil samples. Using the most efficient (a saturated solution of magnesium sulphate plus 5 % potassium iodide) 25 g amounts of 234 environmental soil samples were examined for the presence of Toxocara spp. and Toxascaris ova. Twenty-six samples (11·1 %) yielded ova of one or other species. There was no discernible pattern of distribution of positives with relation to the source of the samples. The maximum number of ova recovered in any one sample was 19. All the ova recovered from the environment were considered viable and potentially infective.

The body wall of the immediate postembryonic juvenile, the preinfective juvenile, the infective juvenile, the moulting juvenile in the host's intestine and the adult of Trichinella spiralis was examined with the electron microscope. The structure and probable mode of development (secretion from the hypodermis) are described. The basic structure of the “mature” cuticle is an outer three-layered membrane, two cortex layers, a medial layer which in the adult is striated, and two fibril layers. The cuticle is attached to an outer corrugated hypodermal membrane by means of desmosomes on the crests of the corrugations. It is thought that the secretion of the cuticle occurs in the trough regions. The hypodermis has the appearance of a highly active layer with an abundance of ribosomes and mitochondria. The hypodermis is cellular and is not a syncytium. Bacillary cells have been demonstrated for the first time in the lateral hypodermal cords of adult T. spiralis. The body wall muscle is similar in structure to that of other nematodes but an increase in the number of muscle cells per intercordal sector from the first-stage juvenile to the adult is recorded and some doubt is therefore cast on the concept of cell constancy in nematodes.