[Nematodes of humans in the Primorye Territory]

Nematodes occupy the top in the general pattern of human parasitic diseases in the Primorye Territory. In the south of the Far East, there are a total of 28 nematode species that can parasitize man. However, the authors have identified only 8 nematode-induced diseases, such as ascariasis, enterobiasis, toxocariasis, trichocephaliasis, anisakiasis, trichinosis, dirofilariasis, dioctophymosis. The latter has been found only once in the 1920s. According to official statistical data, the proportion of ascariasis and enterobiasis accounted for 43.8 and 53.5% of the total number of helminthiases, respectively.

Toxocara malaysiensis n. sp. (Nematoda: Ascaridoidea) from the domestic cat (Felis catus Linnaeus, 1758)

Toxocara malaysiensis n. sp. from the small intestine of the domestic cat (Felis catus L.) in Malaysia is described and illustrated. This ascaridoid nematode was previously assumed to be Toxocara canis, which it superficially resembles, or designated Toxocara sp. cf. canis. The new species differs from T. canis in the shape of the cervical alae in cross section, spicule length, and the lip structure. It is also distinct from other species assigned to Toxocara.

[Soil contamination with Toxocara spp. eggs in the Kraków area and two nearby villages]

The distribution of Toxocara spp. eggs was studied in the Kraków city and nearby villages Grodkowice and Lazkowice. In Kraków out of 80 samples surveyed 30% were positive and the mean egg density was 3.7 eggs/100g soil. Court-yards and squares in the centre of the city were the most heavily contaminated areas (58% samples positive). In two nearby villages Toxocara spp. eggs were present in 16% samples examined and the mean egg density was 0.8 eggs/100g soil. Almost 90% of Toxocara spp. eggs recovered were infective. At least 80% of the eggs were classified as T. cati by egg's morfology.

Adult Toxocara cati infections in U.S. children: report of four cases

We report four cases of passage of subadult or adult Toxocara cati worms by young children ages 20 months to seven years. Worms were expelled rectally in two cases and in two cases they were vomited. A single worm was passed in two cases, three worms in one case, and 15 worms in the fourth case. All worms that were available for study were identified as T. cati by morphologic criteria, including the arrow-shaped cervical alae and the digitiform shape of the male tail. None of the four children exhibited clinical signs of ocular or visceral larva migrans, and in two cases where serum samples were available, neither child had a titer to Toxocara. These results further the argument that these children acquired the worms through the ingestion of immature worms passed by infected cats, not through the ingestion of infective eggs. Although the children were generally not ill as a result of these unusual infections, it does serve to reinforce the public health issue that potential serious consequences can occur where children have exposure to an environment that has been contaminated with cat feces, or, more specifically, infective eggs, and could become infected with larval forms of Toxocara.

Toxocara canis: monoclonal antibodies to carbohydrate epitopes of secreted (TES) antigens localize to different secretion-related structures in infective larvae

The major secreted glycoproteins of Toxocara canis larvae appear to be derived from two specialized organs within the nematode organism. Using immunogold electron microscopy, we have analyzed the binding patterns of a panel of monoclonal antibodies (Tcn-1 to Tcn-8) reactive with Toxocara excretory-secretory (TES) antigens. We find, first, that the esophageal gland and lumen are strongly reactive with monoclonals Tcn-4, Tcn-5, and Tcn-8, and because the posterior portion of the gut is closed, we hypothesize that products of this gland are released through the oral aperture. Second, a distinct anti-TES antibody (Tcn-2) localizes solely to the midbody secretory column, which opens onto the cuticle at a secretory pore. Thus, the secretory apparatus is probably functional in this stage of parasite as an important source of TES products. Only one monoclonal, Tcn-7, can bind to both esophageal and secretory structures. In addition, another antibody, Tcn-3, binds both to the epicuticle and to a TES antigen, but our data do not directly determine whether antigens located in the cuticle are subsequently released. Thus there are at least two, and possibly three, independent sources of TES antigens within Toxocara larvae.

Toxocara canis: a labile antigenic surface coat overlying the epicuticle of infective larvae

An electron-dense coat covering the surface of Toxocara canis infective-stage larvae is described. This coat readily binds to cationized ferritin and ruthenium red, indicating a net negative charge and mucopolysaccharide content, and can be visualized by immuno-electron microscopy only if cryosectioning is employed. Monoclonal antibodies reactive to the surface of live larvae bind the surface coat but not the underlying cuticle in ultrathin cryosections. The surface coat is dissipated on exposure to ethanol, explaining the lack of surface reactivity of conventionally prepared immunoelectron microscopy sections of T. canis. Differential ethanol extraction of surface-iodinated larvae demonstrates that the major component associated with the coat is TES-120, a 120-kDa glycoprotein previously identified by surface iodination, which is also a dominant secreted product. The surface-labeled TES-70 glycoprotein is linked with a more hydrophobic stratum at the surface, while a prominent 32-kDa glycoprotein, TES-32, is more strongly represented within the cuticle itself. Antibody binding to the coat under physiological conditions results in the loss of the surface coat, but this process is arrested at 4 degrees C. This result gives a physical basis to earlier observations on the shedding of surface-bound antibodies by this parasite. An extracuticular surface coat has been demonstrated on Toxocara larvae prior to hatching from the egg and during all stages of in vitro culture, suggesting that it may play a role both in protecting the parasite on hatching in the gastrointestinal tract and on subsequent tissue invasion in evading host immune responses directed at surface antigens.

Morphological observation of Toxocara vitulorum found in Japanese calves

Between 1982 and 1988, ascarid nematodes were found in the feces of Japanese calves in Kyushu and Okinawa districts. Seven males and 21 females of the ascarids were observed morphologically for identification of species. Male and female ascarids were 15.64 (14.0-18.0) cm and 25.75 (16.5-34.0) cm in average length, respectively. Eggs were 81.6 microns and 71.8 microns in large and small diameters, respectively. The body of ascarids was translucent and soft. The boundary between the enlabium and prelabium of lip was clearly visible and the esophageal ventriculus was also observed. The vulva was situated at a distance of about 1/7 approximately 1/9 of body length from the anterior end of body. The surface of egg shell was relatively smooth, without rugose albuminous coat. These morphological features coincided with those of Toxocara vitulorum.

Observations on the morphology of Toxocara pteropodis eggs

Fertile eggs of Toxocara pteropodis, passed in the faeces of juvenile flying-foxes, were ovoid to spheroid in shape with a diameter range of 80-110 microns. The shell was often seen to comprise 4 layers: a fine inner lipid layer, a thicker clear chitinous layer, an equally thick outer vitelline layer and a pitted outermost, proteinaceous uterine layer of variable thickness. Infertile eggs were less uniform in shape and generally did not have well-defined shell layers, the formation of which is triggered by sperm penetration of the oocyte. The eggs of this species are bulkier than those of related ascaridoids, apparently because of a thicker external coat which, while not providing mechanical strength, is thought to protect against desiccation. Scanning electron microscopical findings suggest that the outer layer is not applied directly by uterine cells, but forms by the gradual deposition of secretions in the uterine lumen, regardless of whether the oocyte has been fertilized.

Toxocara vitulorum in the milk of buffalo (Bubalus bubalis) cows

The duration of excretion of Toxocara vitulorum larvae in the milk of buffalo cows determines the optimum time for treating calves. Studies on 10 cows showed that a few larvae occur in the colostrum of some cows before the calf has suckled, but most are present from the day after calving and for a further five days. From day 9 onwards, very few larvae were found in the milk. The total number of larvae found was comparable with the number of adult parasites collected from the calves of cows with similar histories. The larvae were 1254 +/- 60 microns long and 36 +/- 6.7 microns in diameter at the ventriculus, figures which are substantially different from some published results.

The ascaridoid nematodes of rodents with a redescription of Porrocaecum ratti

Two ascaridoid nematodes occurring in rodents in South-East Asia, namelyPorrocaecum rattiandToxocara mackerrasae, were compared; the former was redescribed. These and other ascaridoid species occurring in rodents were classified and it was suggested that relative to the other mammalian orders, the rodents are well endowed with ascaridoids. There is, as yet, insufficient evidence for conjecture as to whether species occurring in rodents represent primitive forms from which the species occurring in predatory animals may have been evolved through host—succession—extension, or whether they have been secondarily derived through loss of a predatory definitive host through host—succession—reduction.

Toxocara vajrasthirae sp.nov. from the hog-badger (Arctonyx collaris) of Thailand

Toxocara vajrasthirae is described from the hog-badger (Arctonyx collaris) of Thailand. Of the species in the genus Toxocara, it most closely resembles T. canis. It differs in the possession of proportionately shorter and narrower cervical alae, relatively longer spicules, a coarse, reticulate pattern on the eggshell and an undivided part of the uterus which is longer than the divided part.

Two new species of Toxocara from viverrid hosts

Toxocara genettaesp.nov. andToxocara sprentisp.nov. from viverrid hosts in Africa and S.E. Asia respectively are described. SevenToxocaraspp. from viverrid hosts are differentiated. The writer proposes thatToxocara canarisiPuylaert, 1967, from a feline host, become aspecies inquirendaerequiring further study.