MORPHOLOGICAL AND BIOLOGICAL DIFFERENCES BETWEEN THE INFECTIVE LARVAE OF ANGIOSTRONGYLUS CANTONENSIS AND THOSE OF ANAFILAROIDES ROSTRATUS

1963 ◽  
Vol 41 (7) ◽  
pp. 1179-1183 ◽  
Author(s):  
Joseph E. Alicata

Third-stage larvae of the rat lungworm, Angiostrongylus cantonensis, can be differentiated from those of the cat lungworm, Anafilaroides rostratus, on the basis of shorter body length, shorter esophagus, and in some cases on the position of the genital primordium. In A. cantonensis the length of the body is 460 to 510 μ and the length of the esophagus, including the buccal cavity, is 171 to 198 μ. The genital primordium is 120 to 135 μ from the anal opening. In A. rostratus the length of the body is 545 to 655 μ, and that of the esophagus is 218 to 246 μ. The genital primordium is 37 to 153 μ from the anal opening. The infective larvae of A. rostratus do not migrate to the central nervous system as do those of A. cantonensis. The larvae of A. rostratus have been found to re-encyst in the liver of rats and mice which serve as paratenic hosts.

1955 ◽  
Vol 3 (1) ◽  
pp. 1 ◽  
Author(s):  
MJ Mackerras ◽  
DF Sandars

Adult Angiostrongylus cantonensis live in the pulmonary arteries. Unsegmented ova are discharged into the blood stream, and lodge as emboli in the smaller vessels. First-stage larvae break through into the respiratory tract, migrate up the trachea, and eventually pass out of the body in the faeces. Slugs (Agriolimax laevis) act as intermediate hosts. Two moults occur in the slug, and third-stage larvae appear about the 17th day. The larvae remain within the two cast skins until freed in the stomach of the rat by digestion. They then pass quickly along the small intestine as far as the lower ileum, where they leave the gut and become blood-borne. They congregate in the central nervous system, and have been found there 17 hr after ingestion. The anterior portion of the cerebrum is the most favoured site, and here the third moult takes place on the sixth or seventh day and the final one between the 11th and 13th days. Young adults emerge on the surface of the brain from the 12th to 14th day, and spend the next 2 weeks in the subarachnoid space. From the 28th to 31st days they migrate to the lungs via the venous system, passing through the right side of the heart to their definitive site in the pulmonary arteries. The prepatent period in the rat usually lies between 42 and 45 days.


1964 ◽  
Vol 42 (4) ◽  
pp. 605-611 ◽  
Author(s):  
Joseph E. Alicata ◽  
Dennis D. McCarthy

Of a total of 240 rats examined on the island of Rarotonga, 85.0% showed lungworm infection. No lungworms were found among 61 rats trapped in and around Auckland, New Zealand, and none among 95 rats trapped in the vicinity of Apia, Western Samoa. Of land mollusks examined on the island of Rarotonga, the following species were found infected with lungworm larvae: (slugs) Deroceras laeve and Vaginalus plebeius, and (snails) Bradybaena similaris and Subulina octona. In addition, a few infective larvae were found among land planarians and freshwater prawns, both of which serve as paratenic hosts. The finding of the rat lungworm on the island of Rarotonga offers an additional example in the Pacific of the occurrence of this parasite in an area where human eosinophilic meningitis occurs.


1979 ◽  
Vol 57 (1) ◽  
pp. 161-178 ◽  
Author(s):  
M. R. Baker

Free-living development of Rhabdias americanus and Rhabdias ranae was heterogonic and development of infective larvae was by matricidal endotoky. Both species were experimentally transmitted by skin penetration. Development of R. americanus in Bufo americanus and R. ranae in Rana sylvatica was similar. Growth of third- and fourth-stage larvae occurred in fascia and muscle tissue of the host during migration to the body cavity. Adult worms were recovered only from the body cavity and lungs; larvae were never observed in these locations. Worms probably entered the lungs by direct penetration. Gravid nematodes were observed only in the lungs. Both R. americanus and R. ranae were transmitted to toad and frog tadpoles, respectively, and worms developed to adulthood in tadpoles. Terrestrial snails (Oxyloma decampi Tryon and Discus cronkhitei Newcomb) were demonstrated as possible paratenic hosts for R. americanus. Rhabdias americanus, which does not occur in frogs, and R. ranae, which does not occur in toads in the wild at Guelph, were experimentally cross-transmitted to these amphibians and developed successfully to adults. Infective larvae of these species, however, did not as readily penetrate into the unusual host as the usual host. It is suggested that ecological barriers have prevented cross infections in the wild.


1962 ◽  
Vol 40 (5) ◽  
pp. 755-760 ◽  
Author(s):  
Joseph E. Alicata ◽  
Robert W. Brown

Infective larvae of the rat lungworm Angiostrongylus cantonensis, the causative agent of parasitic meningoencephalitis in man, have been found in about 4% of the stomach contents of freshwater prawns examined in Tahiti. This is believed to constitute the main source of the local human infection. These crustaceans and "taioro," a food consisting of grated coconut and prawn juice, are commonly eaten raw by Tahitians and some local Europeans. Infected mollusks have also been found on vegetation commonly eaten raw, and may constitute an occasional source of human infection. Laboratory-raised rats have been experimentally infected with A. cantonensis by applying infective larvae on the abraded skin. No infection occurred when the larvae were placed on the intact skin. In addition to land mollusks, the freshwater snail (Fossaria ollula) was also found to be a suitable intermediate host for A. cantonensis.


1975 ◽  
Vol 53 (11) ◽  
pp. 1552-1568 ◽  
Author(s):  
T. F. Mace ◽  
R. C. Anderson

Dioctophyma renale was found in the right kidney of 48% of mink (Mustela vison) trapped in late fall and winter in the Black River area of Ontario. Eggs embryonated at temperatures from 14 C to 30 C. Eggs hatched in the intestine of the aquatic oligochaete Lumbriculus variegatus, and first-stage larvae migrated to the ventral blood vessel where development took place. The first molt occurred about 50 days after infection in oligochaetes kept at 20 C; the second molt occurred about 100 days after infection. Third-stage larvae removed from oligochaetes produced infection in a mink. Larvae given to frogs (i.e. Rana clamitans, melanota and R. pipiens) became encapsulated in the stomach wall or abdominal muscles. A mink was infected with larvae removed from frogs experimentally infected 25 days earlier. A mink was also infected with larvae found in a naturally infected bullhead (Ictalurus nebulosus). Infective larvae of D. renale were found in wild Rana catesbeiana (6.2%), R. septentrionalis (9.6%), and R. clamitans melanota (0.7%) in an area enzootic for dioctophymiasis. It is suggested frogs as well as bullheads are important natural paratenic hosts for D. renale. The various larval stages of D. renale are described and its third-stage larva is distinguished from that of Eustrongylides spp. which may also be found in frogs.


2019 ◽  
Author(s):  
Jared R Widder ◽  
Shamis Fallah ◽  
Todd J Mondzelewski

Abstract Angiostrongyliasis is the most common cause of eosinophilic meningitis worldwide and is primarily characterized by eosinophilic meningitis, meningoencephalitis, or myelitis. It is caused by ingestion of the nematode Angiostrongylus cantonensis, the rat lungworm (or apple snail). The most common route of infection is by ingestion of parts of the intermediate hosts like mollusks or food contaminated with infective third stage larvae. Following ingestion, the larvae migrate through the intestinal walls into the bloodstream and further into the central nervous system where they cause meningo-encephalo-myelitis and can have a variety of ocular manifestations. We present a case of a Caucasian United States Marine who suffered severe meningo-encephalo-myelitis with papilledema following ingestion of a raw Giant African Snail (Lissachatina lutica) while stationed in Japan. He developed eosinophilic meningoencephalitis, polyneuropathy, motor weakness, and papilledema. We describe the unique clinical features of this disease in our patient.


2014 ◽  
Vol 59 (1) ◽  
Author(s):  
Yuriy Kuzmin ◽  
Kerstin Junker ◽  
Odile Bain

AbstractThe morphology of infective third-stage larvae of Rhabdias bufonis, R. rubrovenosa, R. sphaerocephala, R. fuscovenosa, R. elaphe, Entomelas entomelas and E. dujardini is described. The sheath structure in the studied larvae appeared to be similar to that described in other species of the family Rhabdiasidae, its chequered aspect being caused by a combination of outer longitudinal striations and inner longitudinal as well as transverse ridges. The larvae were similar in general morphology but differed in the presence/absence of anterior apical protuberances (pseudolabia), the shape and ornamentation of the tail tip, and the structure of lateral alae in the caudal region of the body. No relationship between the morphological characters of the larvae of the studied species and their taxonomic position or specificity of adult parasites to a particular host group was observed. Regardless, the larvae of each species can be identified by a combination of morphological peculiarities in the anterior and caudal regions of the body.


1993 ◽  
Vol 67 (3) ◽  
pp. 238-242 ◽  
Author(s):  
H. K. Ooi ◽  
K. Ishii ◽  
J. Inohara ◽  
M. Kamiya

AbstractInfective larvae (third-stage larvae) of both Angiostrongylus cantonensis and A. costaricensis from their snail intermediate host were subjected to either X-ray or gamma-ray irradiation. The viability of the irradiated larvae was assayed by oral inoculation of the larvae into rodents (A. cantoflensis in mice and rats, A. costaricensis in mice only). From the results of worm recovery, the minimal dose of irradiation that inhibited the infectivity of the third-stage larvae of A. cantonensis and A. costaricensis was 2 and 4 kGy, respectively.


Author(s):  
F. L. Azizova ◽  
U. A. Boltaboev

The features of production factors established at the main workplaces of shoe production are considered. The materials on the results of the study of the functional state of the central nervous system of women workers of shoe production in the dynamics of the working day are presented. The level of functional state of the central nervous system was determined by the speed of visual and auditory-motor reactions, installed using the universal device chronoreflexometer. It was revealed that in the body of workers of shoe production there is an early development of inhibitory processes in the central nervous system, which is expressed in an increase in the number of errors when performing tasks on proofreading tables. It was found that the most pronounced shift s in auditory-motor responses were observed in professional groups, where higher levels of noise were registered in the workplace. The correlation analysis showed a close direct relationship between the growth of mistakes made in the market and the decrease in production. An increase in the time spent on the task indicates the occurrence and growth of production fatigue.Funding. The study had no funding.Conflict of interests. The authors declare no conflict of interests.


Author(s):  
RR Galimova ◽  
ET Valeeva ◽  
GV Timasheva ◽  
AB Bakirov

Introduction: Production of ethylbenzene and styrene (EBS) is one of the most important stages in organic synthesis. The products have general toxic, hepatotoxic, irritating and narcotic effects on the human body. Severe exposures to EВS can induce pronounced disorders of the central nervous system such as styrene sickness and encephalopathy and of peripheral blood such as leukopenia and lymphocytosis. Materials and methods: We studied homeostasis indices in 376 workers of the main professional groups engaged in the production of EBS including equipment operators, repairmen, and instrumentation and automation fitters. Results: We established an increase in lipid peroxidation by the level of malondialdehyde amid an increase in catalase activity and a decrease in blood retinol and α-tocopherol levels. We also noted an increased activity of indicator enzymes including ALT, AST, GGT, and alkaline phosphatase. Significant changes in lipid metabolism in the form of cholesterolemia, triglyceridemia, a higher atherogenic index, and lower cholesterol of non-atherogenic blood serum lipids demonstrating atherogenic changes in the body were revealed. Conclusions: The earliest prenosological disorders in the body of the examined workers included an impaired hepatic protein synthesis, the development of cytolysis processes and a change in the integrity and functional activity of the liver cell in individuals, an imbalance in the oxidant-antioxidant system, one of the reasons of which was the adverse occupational exposure to hazardous chemicals. An increase in catalase activity is a protective compensatory reaction during the activation of free radical oxidation processes.


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