Two sets of dung-derived organisms from soil routinely fertilized with manure (MA) and soil chemically fertilized (CH) were cultured separately in the laboratory. Baermannized organisms from these cultures were added to 20 g of faeces from strongyle-infected horses to form three treatment groups: (i) no soil organisms; (ii) low inoculum of soil organisms containing all organisms present in a suspension of approximately 100 adult female free-living nematodes; and (iii) high inoculum containing those soil organisms present with approximately 1000 adult female free-living nematodes. Three studies were conducted using MA cultures and faeces containing 50 strongyle epg, CH cultures and faeces containing 1500 strongyle epg, and a mixture of soil organisms from the two cultures (MC) and faeces containing 600 strongyle epg. Within each study, five control cultures and 15 each of low and high inoculum cultures were prepared and incubated at 24°C and 95% humidity in a climate chamber for 15 days. Parasitic and free-living nematodes were then recovered by the Baermann technique and counted. The numbers of third stage larvae were significantly lower in the high inoculum group compared to controls. The percent reductions in the number of third stage larvae for the low and high inoculum groups were 63.6% and 90.9%, 85.1% and 97.1%, 84.5% and 98.4% for MA, CH, and MC studies, respectively, indicating that mortality increased with the number of soil organisms added to cultures. Examination of the source cultures detected the presence of two species of nematophagous fungi and three genera of free-living nematodes reported to be predacious.

Dentostomella kuntzi is redescribed from specimens found in the rodent hosts Acomys cahirinus, Arvicanthis niloticus and Rattus rattus from the Giza province of Egypt, and compared with three species of the genus Dentostomella namely D. grundmanni, D. legerae and D. translucida. Unlike other species in the genus, the egg of D. kuntzi is operculate. The distribution of adult D. kuntzi within the intestine of Acomys cahirinus is also discussed.

A comparative analysis has been carried out between two populations of Schistosoma haematobium using the same intermediate snail host, Bulinus truncatus, but originating from two distinct ecological areas of Algeria: Khemis-El-Khechna in a sub-humid mediterranean zone and Djanet in a saharan bioclimatic zone. Four parameters have been studied: the growth rate of adult worms, size and shape of the eggs, chronobiology of cercarial emergence and the compatibility with the intermediate host. Results showing divergences for all the characters studied are discussed for the origin of this intraspecific polymorphism of S. haematobium in Algeria.

Ethyl-6-ethoxybenzothiazole-2-carbamate (Sch 18099) was evaluated for efficacy against natural helminth infections in ponies, pigs, lambs and chickens.

Sixteen critical trials were conducted in ponies at dosages of 15 to 150 mg/kg. At 15 mg/kg, efficacy against adult and larval Oxyuris equi was 100% and 91% and against small strongyles it was 98%. Efficacy levels were >95% against Strongylus vulgaris and S. edentatus at the 20 mg/kg dosage. In two trials at 100 mg/kg efficacy against Parascaris equorum was 77%. No efficacy was observed against Gastrophilus spp. or Anoplocephala spp.

In swine single oral doses of 10 to 100 mg/kg were not effective. 500 ppm Sch 18099 in the diet for seven days resulted in 100% efficacy against Ascaris suum and Trichuris suis but had no effect on Strongyloides ransomi. Efficacy at 250 ppm against A. suum was 77%.

Efficacy at 200 mg/kg in lambs was >90% for Haemonchus contortus, Trichostrongylus axei, Marshallagia marshalli, Bunostomum trignocephalum, Oesophagostomum columbianum, Trichuris ovis, and Chabertia spp. Efficacy was <80% for Trichostrongylus vitrinus, Nematodirus filicollis, Ostertagia circumcinta and Cooperia curticei. Except for O. circumcinta and C. curticei, drug efficacy was reduced for these worms in lambs treated at 100 mg/kg.

Efficacies of 14˙3–89% against Ascaridia galli were obtained with dietary levels of 125–1000 ppm Sch 18099 fed for 7 days. Efficacy of 100% was recorded against Heterakis gallinarum at the 1000 ppm dietary drug level.

The microfilarial level in the peripheral blood of Mastomys natalensis infected with the filarial parasites, Litomosoides carinii, Brugia pahangi, B. malayi and Dipetalonema viteae was monitored at two-hour intervals for 24 hours. The microfilariae of B. pahangi and B. malayi exhibited nocturnal and diurnal subperiodicity, respectively; no such periodicty was seen in L. carinii and D. viteae infections.

The level of B. pahangi and D. viteae microfilariae in peripheral blood was significantly increased when the host was anaesthetized with diethylether or pentothal sodium. Ether-induced anaesthesia had no effect on tne level of B. malayi microfilariae but pentothal was most effective. The peripheral blood count of L. carinii microfilariae tended to decrease in the anaesthetized animals but the reduction was not statistically significant.

In 1928 a description of the morphology of three strains of Heterodera schachtii attacking beet, oats and potatoes respectively, was published in the Journal of Helminthology by the present writer. This was followed in 1929 by a second publication in which the morphology of strains of the nematode attacking beet, oats, hops, mangolds and potatoes were described. In the earlier paper it was noted that cysts of the potato-strain in Hertfordshire were smaller both in average and maximum dimensions than were cysts in soil from South Lincolnshire. The Hertfordshire land had been infected by the addition of South Lincolnshire soil and the reduction in cyst-size occurred in adjacent portions of the plot to which the infection had spread during the cultivation of two successive potato crops. It was concluded that this decrease in size was a reaction to the difference in soil type, possibly associated with available oxygen.

The combined use of complement fixation (CF) and latex agglutination (LA) tests is reported on sera from 6328 patients with suspected hydatid disease; 191 were confirmed positive at operation (‘known positives’). Results by LA are related to CF titres.

Both tests were negative in 90% of specimens. Nine patients were subsequently found infected of whom 3 became positive in tests after operation.

Of sera positive in both tests, 75% were from ‘known positives’. The remainder were almost certainly from infected patients.

Half the patients whose sera were La positive/CF⋜¼ were follow-up ‘known positives’ in whom CF titres had waned; 2 were early infections.

Only 3% of the cases with an LA negative/CF titre of ⋝1/16 were ‘known positives’ and 6% where the CF titre was 1/8. The remaining CF results in the group were false positives and accounted for 1.2% of all sera tested. Findings show that a CF titre ⋝1/8 with positive LA indicates past or present infection; a negative CF test with positive LA usually indicates past infection; rarely, infection is present when a CF titre is ⋝1/8 and LA is negative. A rising CF titre and positive LA indicates current infection; reliable prognosis following treatment is given by CF.

A new genus of nematode (Paratrichosoma crocodilus) is described from Crocodilus novaeguinae. Adults have typical trichuroid features but elongated stichocytes (over 1 mm in female). Males are one third to one half as long as females and have no spicule or sheath.

Free-living nematodes commonly occur in cultures of fæces, and as Looss (1911) showed years ago they have frequently been mistaken for the developmental stages of parasitic nematodes. For this reason it is important that detailed knowledge of the morphology of such free-living forms should be available. With this end in view the following illustrated account of what appears to be a new genus of nematode has' been prepared. The worms occurred originally in a culture of the fæces of a brown rat, Rattus norvegicus, made for the study of the free-living stages of the Strongyloides of the rat; and as after detailed study it has been found impossible to find any existing description of nematodes which agree with the structural appearances shown by the worms, it has been decided to create a new genus for their reception.

Afromacroderoides lazerae gen. et. sp. nov. (Allocreadiidae; Walliniinae) is described and figured from specimens collected from the intestine of the African freshwater fish Clarias lazera from the White Nile near Khartoum, Sudan. The new genus is distinguished by the shape of its cirrus sac, the presence of a bipartite seminal vesicle and a spiny cirrus. It is differentiated from the related genera Paramacroderoides and Pseudoparamacroderoides.

Cortisol production in fry of rainbow trout (367–456 mg body weight) infected with the ectoparasitic monogenean Gyrodactylus derjavini (mean intensities 4.7 and 4.9 parasites per fish) was studied at two temperature levels, 4–6°C and 11–12°C, respectively. Due to difficulties in obtaining an adequate amount of plasma from the small sized fish, the corticosteroid concentration was measured in the body fluid recovered (as supernatant) after sonication and centrifugation of whole fry. Infected fry at 11–12°C showed an elevated level of cortisol compared to uninfected fry. However, the cortisol concentration was lower than in fish exposed to handling stress. At 4°C, the cortisol level in infected fish compared to uninfected was insignificantly increased. The findings are discussed in relation to the role of monogeneans as inducers of secondary infections.

In a varied collection of parasitic worms sent by Dr. G. M. Heydon, of Raboul, New Guinea, to Prof. R. T. Leiper, Director of this Institute, there were a number of specimens of Œsophagostomum dentatum which had been taken from the large intestine of a pig. An accompanying letter stated that the pigs at Roboul are crossbred between the local wild pig and European breeds.

For many years past, Syngamus has been recognised as a serious trouble in both avian and mammalian hosts, and the course of the disease has been closely followed in several birds of economic importance. The symptoms are well known and have often been cited. Clinically the first symptom to appear is a characteristic sneezing and coughing in the affected bird. This is followed later by the best known symptom—the actual gaping—when the bird stretches its neck and opens its beak widely in its endeavour to ease respiration. There are minor signs such as a general debility with ruffled feathers but these are secondary and not specific to this disease. Internally in the trachea there is an increase in the secretion of mucus, which coupled with the presence of the gapeworms is sufficient to cause asphyxiation and the bird dies.

The tegument of juvenile Paramphistomum epiclitum and Fischoederius elongatus (Paramphistomidae: Digenea) resembles those of other digeneans. Seven types of papillae were observed, mostly on the oral and acetabular surfaces, and increase in number during migration. Also evident are two types of secretory body (T1 and T2) which are synthesized separately in tegumental cytons underlying the syncytium. Exocytosis of T2 bodies occurs at the apical membrane and appears to contribute to a fibrous glycocalyx. The tegumental syncytium lining the pharynx and acetabulum is thinner and has a higher capacity for vacuolation than the general tegument. These may represent important sites for osmoregulation. The absence of mitochondria from the tegument in migrating juveniles suggests limited involvement in energy demanding processes. Pigmentation of the subtegument is first evident in mature cercariae and is progressively eliminated during migration.

1. The protozoa reported from animal-parasitic helminths are summarised in three tables, with a few comments on some of the more interesting forms.

2. The microsporidian found hyperparasitic in Moniezia expansa and M. benedeni of sheep in England, and Moniezia sp. from a buffalo calf in Pakistan has been found to be identical with Nosema helminthorum described by Moniez, 1887, Plistophora helminthophthora Labbé, 1899, and Nosema bischoffi, Weiser, 1951. The valid name for the organism is therefore Nosema helminthorum Moniez, 1887.

3. The macroscopic and microscopic changes in parasitized tapeworms have been described, and it is believed that the microsporidian is not pathogenic.

4. The host distribution and the geographical distribution of Nosetna helminthorum have been dealt with. This parasite has so far been reported from France, Germany, Yugoslavia, Great Britain and Pakistan, and it is likely that, it will eventually be reported from other countries in which Moniezia is present.

1. Ninety-six lesser black-backed gulls, Larus fuscus L., captured at about 6 weeks of age, were kept in captivity for up to 2⅛ years. At intervals some gulls were killed and examined for helminth parasites, of which 14 species were found comprising 4 species of Trematoda, 5 species of Cestoda and 5 species of Nematoda.

2. Nine of the 14 species are commonly found in Holarctic gulls and may be regarded as characteristic members of the helminth fauna of these birds. Six species are recorded from L. fuscus for the first time.

3. The life span of different species of helminth parasites in L. fuscus varied from 2 months to 2⅛ years; few specimens lived in their host for more than one year. During captivity there was a marked decline in the variety of the helminth fauna of individual gulls, as well as a general decline in the incidence and intensity of infection with individual species of parasites. There was one exception, the tape-worm Tetrabothrius cylindraceus, which increased in incidence and maintained a fairly even intensity of infection in L. fuscus over 21 months. The results are discussed in relation to the ecology of the parasite and the host.

In 1865, Leuckart described from the stomach of the domestic cat, a minute bursate worm which he named Ollulanus tricuspis. His original description was somewhat scanty, but it was amplified in later years (1867–1876). As this work is scattered throughout many pages, the following is a brief resumé of Leuckart's theory.

He was struck by the fact, that being viviparous in habit, it resembled Trichinella spiralis, but recognised that several fundamental differences existed between them. Ollulanus never produced more than three larvae at a time from relatively large eggs, about 60μ to 120μ long; whereas Trichinella produced numerous larvae with small eggs about 35μ long. He found what he believed were the free larvae of Ollulanus, which measured about 320μ long by 15μ wide, had a truncated oral extremity and a short tail which ended in a short S-shaped tip (Fig. 1, a). The oesophagus was between one third and one half of the total length of the intestine; several transparent vesicles could be seen at its clubshaped posterior extremity. Although there are seldom more than three embryos inside the female, larvae were usually, found in large numbers throughout the whole intestinal tract of the host, as well as encysted (in cysts ·15 to ·2 mm. in diameter) on various internal organs. The cyst wall had a connective tissue-like structure of such thickness that it might be three or four times the diameter of the enclosed space.

Toxocariasis is an emerging zoonotic disease caused by Toxocara canis and T. cati. Toxocariasis and its etiological agents are of global public health importance, whose burden appears underestimated, especially in sub-Saharan Africa (SSA). The diversity in the transmission routes of these parasites contributes to disease prevalence and often hinders disease control measures. This study aimed to review the epidemiological distribution of Toxocara infections in SSA region. A systematic review and meta-analysis were performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis). We identified 94 relevant, peer-reviewed articles, out of which, 75 articles were found eligible based on Toxocara infections in dogs, cats and humans. Overall, 27,102 samples were examined for T. canis in dogs, T. cati in cats and Toxocara serology in humans, out of which 6142 were positive for Toxocara infection: 3717 (13.7%) in dogs (faecal, 3487; necropsy, 180; hair, 50); 266 (1%) in cats (faecal, 101; necropsy, 165); and 2159 (8%) in humans (serology). Overall mean prevalences of 19% (95% confidence interval (CI): 14–23%), 9% (95% CI: 0–28%) and 36% (95% CI: 24–49%) were recorded in dogs, cats and humans, respectively. Substantial heterogeneity was observed between studies and subgroups (I2 = 99%, P < 0.01). Findings from the review showed that studies on the epidemiology of Toxocara infections in the SSA region are limited. We strongly recommend focused, collaborative and coordinated studies to determine Toxocara spp. prevalence in various hosts, including food animals and the environment, through a ‘One Health’ approach across SSA countries.

The current study was designed to increase the spermatological ultrastructural database on Digenea, thus contributing to the future establishment of phylogenetic relationships within this group based on ultrastructural characteristics of both spermiogenesis and spermatozoa. Spermiogenesis in Elstia stossichianum begins with the formation of a differentiation zone containing two centrioles, two striated rootlets, a nucleus, several mitochondria and an intercentriolar body constituted by seven electron-dense layers. Each centriole develops into a free flagellum growing orthogonally to the median cytoplasmic process. Proximo-distal fusion of the flagella with the median cytoplasmic process occurs after flagellar rotation. Both nucleus and mitochondria migrate before the complete proximo-distal fusion of both flagella with the median cytoplasmic process. Finally, the constriction of the ring of arched membranes gives rise to the young spermatozoon. The mature spermatozoon of E. stossichianum exhibits two axonemes of different length of the 9+‘1’ trepaxonematan pattern, a nucleus, a mitochondrion, two bundles of parallel cortical microtubules, external ornamentation of the plasma membrane, a lateral expansion, spine-like bodies, cytoplasmic ornamented buttons and granules of glycogen. The formation of cytoplasmic ornamented buttons during the final stages of spermiogenesis is reported here for the first time.

Experimental infections of Lymnaea glabra (two populations) with Fasciola hepatica were carried out during seven successive snail generations, to determine if prevalence and intensity of snail infection increased over time through descendants of snails already infected with F. hepatica. Controls were descendants coming from uninfected parents and infected according to the same protocol. No larval forms were found in the bodies of control snails coming from uninfected parents. In contrast, prevalence and intensity of F. hepatica infection in snails originating from infected parents progressively increased from the F2 or F3 to the F6 generation of L. glabra. In another experiment carried out with the F7 generations of L. glabra and a single generation of Galba truncatula (as controls), the prevalence of F. hepatica infection and the total number of cercariae were lower in L. glabra (without significant differences between both populations). If the number of cercariae shed by infected snails was compared to overall cercarial production noted in snails containing cercariae but dying without emission, the percentage was greater in G. truncatula (69% instead of 52–54% in L. glabra). Even if most characteristics of F. hepatica infection were lower in L. glabra, prevalence and intensity of parasite infection increased with snail generation when tested snails came from infected parents. This mode of snail infection with F. hepatica suggests an explanation for cases of fasciolosis occurring in cattle-breeding farms where paramphistomosis is lacking and G. truncatula is absent.