An attempt was made to identify the human hookworm involved in failed-treatment cases using abnormal hosts and scanning electron microscopy. Thirty-seven, 2 to 6 month old Chinese hamsters (Cricetulus griseus) from a closed, outbred, conventional colony, were each given between 20 and 120 filariform larvae per os. The larvae were cultured from faeces from mebendazole (Vermox®) 500 mg single-dose, failed-treatment cases living in the lowveld farming area of the Transvaal Province, South Africa. About 60 to 78 days after inoculation, the animals were killed and adult worms were removed from their small intestines. Eleven (30%) of the 37 hamsters harboured a total of 31 adult worms (19 males and 12 females), while 26 hamsters were refractory to infection. The greatest number of worms recovered from a single animal was six. A total of 27 worms (17 males and 10 females) were subjected to examination by scanning electron microscopy. Micrographs showed male and female worms to be morphologically all of the Necator americanus species, as identified by a pair of ventral and dorsal cutting plates, a dorsal tooth and the fused terminus of spicules in the male bursa. The transverse cuticular striations were distinct and smooth. Several points of interest arose from the results of this study and are discussed.

Onchocerca lienalis microfilariae (mf) were cryopreserved in liquid nitrogen within skin-snips using methanol as a cryoprotectant and their viability evaluated and compared to mf cryopreserved free of host tissues using ethanediol as a cryoprotectant. Despite an initial delay in emergence, the methanol technique did not significantly affect the total numbers of mf emerging from skin-snips of various sizes (3·3–59·81 mg) compared to untreated controls over a 6 h period. Following thawing, the initial motility index (MI) scores of mf cryopreserved by either method were not significantly different from untreated controls; however, over a period of 15 days in culture the MI scores of both cryopreserved groups showed a small but significant overall decline, with the methanol technique producing the lowest scores. These changes in motility levels correlated with the numbers of mf which developed to the infective stage following intrathoracic injection into Simulium ornatum, although this ability to develop was a much more sensitive measure of parasite viability; compared to untreated control recoveries of 3rd-stage larvae, 63·9–71·7% (ethanediol technique) and 34·2–36·9% (methanol technique) of this number were recovered from cyropreserved groups. There were no significant differences in the lengths of infective larvae recovered from the insect heads from each treatment group, nevertheless there were higher numbers of 2nd-stage larvae recovered from the cryopreserved groups compared to the untreated controls. The methanol technique has the advantage of being easier to carry Out under field conditions, while parasite viability is significantly better using the ethanediol technique.

The prevalence of guinea worm Dracunculus medinensis was determined in communities in Anambra State, Eastern Nigeria during the 1984–1985 guinea worm season. Thereafter combined intervention measures which included health education and community participation in pond treatment were introduced in one of the two communities. There was a decrease in disease prevalence from 88.7% to 33% in Group A (372 households) and from 88% to 53% in Group B (368 households), two years after control measures were introduced in Igbeagu community. However, in 345 households in Mpu community without control measures, any decrease was not significant (from 88·7% to 86·5%). Health Education combined with pond disinfection proved to be a much better intervention measure, contributing to the change in attitude and therefore decrease in disease prevalence, than pond disinfection alone.

A method for hatching second-stage larvae of Toxocara canis is described. Whole adult worms are processed by centrifugation in the presence of hypochlorite which allows the grinding step to be eliminated. The technique is more rapid and a high yield is obtained.

Parasitic larvae of Rhabditis orbitalis (formerly confused with Pelodera strongyloides) were found in the conjunctival sacs of the eyes of Apodemus argenteus and A. speciosus from Japanese islands.

An immunodominant antigen of Dirofilaria immitis was studied using recombinant DNA techniques. The mRNA from D. immitis adult female worms was translated in vitro and a major 34 k Da antigenic polypeptide product was demonstrated by immunoprecipitation. cDNA was synthesized from mRNA and a λ gt11 expression library was constructed and immunoscreened with dirofilariasis positive serum. A positive clone containing a nearly full length cDNA was isolated. The cDNA was 2415 bp in length and consider of a single open reading frame followed by a long 3' non-coding region of 1446 bp. The open reading frame of 969 bp encoded a polypeptide of 322 amino acids with a molecular weight of 34 400. A cDNA fusion protein synthesized by bacteria (Escherichia coli JM109) using the expression vector pGEMEX-1 was identified as an immunodominant antigen by absorption experiments and had no cross-reactivity with sera from patients with other filarial species.

Results of the incorporation of carbon from 14C-glycerol into total, polar and nonpolar lipids in Haemonchus contortus (Nematoda: Trichostrongylidae) reveal that the radioactivity lost into the medium as lipids decreased during the first 3 h of incubation. This was followed by a drastic increase during the 4th h. Again, there was a decline by 75% during the 5th h. However, there was a slight increase in the nonpolar lipids during the 5th h.

Dirofilaria immitis (the dog heartworm) microfilarial periodicity was determined hourly for five days in an infected dog from Kambai village in Muheza district Tanzania. Maximal microfilarial counts were found at 1100 h and minimal at 2200 h. This finding represents the first record of D. immitis microfilarial periodicity in Tanzania.

Acetic orcein stain may be dropped onto the specimen before applying a cover slip. This single reagent reveals cercarial and metacercarial structures that would otherwise be made visible only by complicated and time consuming procedures

Of 756 dog faecal deposits collected from the road side and public places in five Jordanian Governorates 466 (61·6%) harboured parasite ova, oocysts and/or larvae. Of these, 67·7%, 26·8%, 4·1% and 1·4% revealed one, two, three and four different types of parasite ova, oocysts or larvae in the same sample, respectively. Examination of the infected samples revealed that 44·1% contained taeniid ova, 19·8% Dipylidium caninum, 19% Toxocara canis, 8% Sarcocystis spp. oocysts, 5% hookworm larvae, 1·5% Diphyllobothrium latum, 0·1% Capillaria spp. and 0·1% Trichuris vulpis eggs.