Observations on the course of Hymenolepis nana infection in immunosuppressed mice are presented. Treatment of the host with hydrocortisone acetate caused superinfection of the bowel with worms and the development of normal cysticercoids in the mesenteric lymph node and liver. Natural infection of mice deprived of their T-cells by pre-adult thymectomy and administration of antithymocyte serum resulted in superinfection and widespread metastasis of aberrant cysticercoids that were greatly enlarged and without scolices, causing death after about five months. The significance of these findings and their possible relevance to human infection with H. nana are discussed.

The presence of precipitin antibody and soluble circulating antigen was demonstrated in sera of individuals with clinical filariasis by counterimmunoelectrophoresis. Antigens derived from Litomosoides carinii and antisera raised in rabbits to the adult worm antigens were used for the detection of antibody and antigen in human sera. Of 35 subjects, 2 had microfilariae in the peripheral blood, 9 soluble circulating antigen, 19 antibody in sera, and 6 had both antigen and antibody. It suggests that 5.7% of cases diagnosed as bancroftian filariasis by parasitological examination can be increased to 62.8% by serological means.

Incidence of mating pairs in 40 worm infections in 5 week old female CBA mice increased up to day 30 post infection. By this time, and thereafter until the experiment ended on day 70, approximately 60% of the worm population occurred as mating pairs. Mating began during the ontogenetic migration of the worms. There was no difference between the percentage of worms mating in the more highly populated anterior sections of the small intestine as compared to the less densely populated more posterior sections. Significantly more female than male worms were recovered between days 8 and 20 post infection (p<0.02 to 0.001) and there was a significant decline in overall recoveries during the experimental period (r = −0.77, p<0.01). Low intensity infections, with 4 to 16 worms per mouse, demonstrated that a larger percentage of worms in the infection were mating at an earlier time post infection than in the 40 worm infections. Ontogenetic migration was reduced in low intensity infections because the initial distribution of worms was more restricted.

Collyricloides massanae (Trematoda: Collyriclidae) is described from cysts in the wall of the small intestine of a starling (Sturnus vulgaris L.) in the Netherlands. The original description was from a yellow necked mouse, Apodemus flavicollis (Melchior), so this is the first record of this species in birds.

Necator americanus, originally isolated from man, developed completely in infant rabbits (RSG-1). This infection was serially passed in infant rabbits up to the 6th generation without using any immunosuppressant. Two day old infant rabbits demonstrated a high degree of susceptibility to N. americanus. Studies revealed the retention of worms in the intestine for more than 150 days during which egg production was high. In this experimental model the leukocyte, antibody and serum protein responses due to N. americanus infection were monitored. Results showed that eosinophil numbers rose significantly from day 28 to 170. A maximum was observed on day 80 (41%) in rabbits of the fourth generation. Antibodies to N. americanus were detectable in infected rabbits by counterimmunoelectrophoresis using third stage larval antigen (Rabbit strain). Generally, total globulins increased with decrease in albumin. Serum protein increase was associated with alpha-2, beta and gamma globulin components.

Two hundred one-day-old male white leghorn chikens (Gallus domesticus) divided into 4 groups were inoculated with a single dose of 500, 1000, 2000 or 4000 filariform larvae of Ancylostoma caninum. Larval recoveries were made from different tissues at intervals from 4 hours to 72 hours after infection. Larval migration in the heart took place within 4 hours in all the groups except group A with 500 larvae and in thoracic muscle at 8 hours. Larvae also migrated into liver, lungs and neck muscle within 12 hours and into leg muscle at 18 hours. No larvae were recovered from the muscles after 72 hours of infection. Larvae did not migrate into kidney, spleen and central nervous system throughout the experimental period.

Adult worms of the rural strain of Wuchereria bancrofti in Peninsular Malaysia obtained from a successful experimental transmission in an immunosuppressed Macaca fascicularis are described for the first time. Although the worms, especially females, were slightly smaller, they were similar in morphology to those of the periodic and non-periodic W. bancrofti previously described.

Nilocotyle duplicisphinctris sp. n. was recovered from the stomach of Hippopotamus amphibius in Ethiopia. The average body size (L × W) is 3.6 × 1.2 mm; pharynx 0.5 × 0.3, Dicranocoelium type; other diameter of the acetabulum 0.85, Nilocotyle type; anterior testis 0.34 × 0.49; posterior testis 0.32 × 0.27; ovary 0.27 × 0.19; genital opening 0.30 × 0.34, Duplicis phinctris type and eggs 0.15 × 0.07. The most characteristic specific feature is the presence of a double sphincter along the genital atrium.

Echidnotaenia gen. nov. (Anoplocephalata: Linstowiidae) is proposed for Cittotaenia tachyglossi Johnston, 1913 from the monotreme Tachyglossus aculeatus Shaw, 1792. The new genus is distinguished from other genera of the Linstowiidae by its paired genitalia and aporally extended vitellaria.

Dauerlarvae of Pelodera strongyloides, recovered from two species of lemmings, Dicrostonyx groenlandicus (Traill) and Lemmus trimucronatus (Richardson) trapped at Eskimo Point, N. W. T., were cultured on agar medium with E. coli. Development from egg to adult stage was followed. Eggs hatched between 22 and 26 hours at 22°C. The first moult occurred 24 to 28 hours after the eggs hatched, the second at 40 to 48 hours, the third at 60 to 64 hours and the fourth at 84 to 88 hours at 22°C. Adults lived approximately 5 to 6 days and females oviposited for 2 to 3 days during this time. All stages were measured and described. The effect of temperature on development was examined. Dauerlarvae survived freezing temperatures, short periods of desiccation and prolonged periods without food.

The indirect fluorescent antibody technique has been applied to detect antibody levels in jirds (meriones unguiculatus) infected with Brugia malayi. Sonicated antigens were prepared from microfilariae and adult worms. Sonicated microfilariae were found to be satisfactory for this purpose. Cyanogen bromide-activated sepharose coated with soluble antigens prepared from microfilariae and adult worms was also used to detect antibodies to Brugia infections. The present observation show that these techniques can be usefully applied for detection of filarial infections. Antibody titres in infected jirds generally ranged from 1: 16 –1:256 and were not affected by treatment with diethylcarbamazine.

Antibody levels were investigated in rats infected with Breinlia booliati using the indirect immunofluorescent antibody technique. Sonicated antigens were prepared from microfilariae and adult worms. Adult worm antigen was rather unsatisfactory. The sonicated microfilarial antigen was useful in detecting antibodies in various groups of rat sera. Very high antibody levels were seen in amicrofilaraemic rats harbouring unisexual infections of varying worm loads. The singnificance of these observations are discussed.