STUDIES ON THE BIONOMICS AND CONTROL OF THE BURSATE NEMATODES OF HORSES AND SHEEP: VIII. COMPARISONS OF THE LETHAL EFFECTS OF SOME CHEMICALS CONTAINING SULPHUR ON THE FREE-LIVING STAGES OF SCLEROSTOMES

1940 ◽  
Vol 18d (11) ◽  
pp. 371-394 ◽  
Author(s):  
I. W. Parnell
Keyword(s):  
Carbon Disulphide ◽  
Strong Solutions ◽  
Sodium Sulphate ◽  
Zinc Sulphide ◽  
Ferric Sulphate ◽  
Sodium Sulphide ◽  
Free Living ◽  
Third Stage ◽  
Medium Strength ◽  
And Control

The effect on the free-living stages of sclerostomes of 14 common chemicals containing sulphur is discussed. Potassium xanthogenate in weak solution will sterilize about 160 times its weight of fresh faeces; in a strong solution, less than a quarter of the weight. Carbon disulphide will sterilize only about 32 times its weight under the conditions imposed by this technique. In solutions of medium strength the sulphates of zinc will sterilize 32 times, and those of iron (ferrous), copper, and manganese, 13 times their weight; lesser quantities, however, might be effective in practice, because the larvae from cultures so treated die comparatively rapidly after reaching the third stage. Dry ferric sulphate will sterilize 20 times its weight. Sodium sulphide, sodium sulphite, and sodium sulphate are all so ineffective that only when applied dry or as strong solutions are they lethal; they sterilized from eight to five times their weight. Magnesium sulphate will sterilize only four times and zinc sulphide twice its weight of fresh faeces. Ferrous sulphide and flowers of sulphur do not appear to have any lethal value, but the latter may, by controlling antagonistic factors, increase the chances of survival of the larvae.

STUDIES ON THE BIONOMICS AND CONTROL OF THE BURSATE NEMATODES OF HORSES AND SHEEP: VI. ON THE LETHAL EFFECTS OF SOME NITROGENOUS CHEMICALS ON THE FREE-LIVING STAGES OF SCLEROSTOMES

1939 ◽  
Vol 17d (3) ◽  
pp. 68-86
Author(s):  
I. W. Parnell
Keyword(s):  
Weak Solution ◽  
Ammonium Nitrate ◽  
Ammonium Carbonate ◽  
Free Living ◽  
Lethal Effects ◽  
The Third ◽  
Cupric Nitrate ◽  
Third Stage ◽  
Medium Strength ◽  
And Control

The effect of ten chemicals, containing a nitrogen radicle, on the free-living stages of Sclerostomes is discussed. Chloropicrin is the most lethal chemical yet tested; under the conditions of these tests, one part of chloropicrin will sterilize approximately 2,300 times its weight of fresh faeces, but its disadvantages weigh against its practicability for farm use. Aniline will sterilize about 525 times its weight of fresh faeces when undiluted and 800 or 900 times its weight as a very weak solution. Calcium cyanide, whose value is also limited by its danger, will sterilize 530 times its weight of fresh faeces. Pyridine is slightly more effective when applied undiluted or as a strong or medium strength solution; it will then sterilize about 400 times its weight of fresh faeces. Ammonium carbonate will sterilize approximately 50 times its weight of fresh faeces. Ammonium chloride, cupric nitrate, and ammonium nitrate will sterilize approximately 30, 25, and 21 times their own weight of fresh faeces respectively. They are, however, more effective if applied as medium strength solutions, and cupric nitrate in lesser amounts causes the death of many larvae after they have reached the third stage, although the chemical was added to the fresh faeces. Ammonium sulphide, as a 15% solution, will sterilize nearly 14 times its weight of fresh faeces. Saponin probably has no lethal value against Sclerostomes chemically, although physically it may affect them.

STUDIES ON THE BIONOMICS AND CONTROL OF THE BURSATE NEMATODES OF HORSES AND SHEEP: IV. ON THE LETHAL EFFECTS OF SOME NITROGENOUS FERTILIZERS ON THE FREE-LIVING STAGES OF SCLEROSTOMES

1937 ◽  
Vol 15d (7) ◽  
pp. 127-145 ◽  
Author(s):  
I. W. Parnell
Keyword(s):  
Strong Solution ◽  
Ammonium Sulphate ◽  
Sodium Nitrate ◽  
Calcium Nitrate ◽  
Potassium Nitrate ◽  
Diammonium Phosphate ◽  
Free Living ◽  
Lethal Effects ◽  
Medium Strength ◽  
And Control

The effect of ten of the commoner nitrogenous fertilizers on the free-living stages of Sclerostomes, is discussed. Urea is the most lethal. Under the conditions of the experiments, which are otherwise ideal for the survival of the larvae, one part of urea to 125 parts of fresh horse feces is necessary to sterilize them. The proportions of the others tested are: Calurea, 1:80; powdered cyanamide, 1:50, with granular cyanamide slightly lower; potassium nitrate, sodium nitrate and Calnitro, 1:20; calcium nitrate and diammonium phosphate (dry or in medium strength solution) 1:17; Nitro-chalk, about 1:16 (but should not be used in strong solution); ammonium sulphate, 1:14.

scholarly journals Chemosensory mechanisms of host seeking and infectivity in skin-penetrating nematodes

2020 ◽  
Vol 117 (30) ◽  
pp. 17913-17923 ◽  
Author(s):  
Spencer S. Gang ◽  
Michelle L. Castelletto ◽  
Emily Yang ◽  
Felicitas Ruiz ◽  
Taylor M. Brown ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Strongyloides Stercoralis ◽  
Sensory Cues ◽  
Ancylostoma Ceylanicum ◽  
Free Living ◽  
Infective Larvae ◽  
Host Seeking ◽  
Third Stage ◽  
Olfactory Preferences ◽  
Insight Into

Approximately 800 million people worldwide are infected with one or more species of skin-penetrating nematodes. These parasites persist in the environment as developmentally arrested third-stage infective larvae (iL3s) that navigate toward host-emitted cues, contact host skin, and penetrate the skin. iL3s then reinitiate development inside the host in response to sensory cues, a process called activation. Here, we investigate how chemosensation drives host seeking and activation in skin-penetrating nematodes. We show that the olfactory preferences of iL3s are categorically different from those of free-living adults, which may restrict host seeking to iL3s. The human-parasitic threadwormStrongyloides stercoralisand hookwormAncylostoma ceylanicumhave highly dissimilar olfactory preferences, suggesting that these two species may use distinct strategies to target humans. CRISPR/Cas9-mediated mutagenesis of theS. stercoralis tax-4gene abolishes iL3 attraction to a host-emitted odorant and prevents activation. Our results suggest an important role for chemosensation in iL3 host seeking and infectivity and provide insight into the molecular mechanisms that underlie these processes.

The life cycle of Paraquimperia tenerrima: a parasite of the European eel Anguilla anguilla

2005 ◽  
Vol 79 (2) ◽  
pp. 169-176 ◽  
Author(s):  
J.A. Shears ◽  
C.R. Kennedy
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Temperature Dependent ◽  
Free Living ◽  
Freshwater Invertebrate ◽  
Third Stage ◽  
History Of ◽  
Whole Life Cycle

AbstractPrevious studies on the life history of the nematode eel specialist Paraquimperia tenerrima (Nematoda: Quimperiidae) have failed to determine whether an intermediate host is required in the life cycle. In the laboratory, eggs failed to hatch below 10°C, hatching occurring only at temperatures between 11 and 30°C. Survival of the free-living second stage larvae (L2) was also temperature dependent, with maximal survival between 10 and 20°C. Total survival of the free-living stages (eggs and L2) is unlikely to exceed a month at normal summer water temperatures, confirming that parasite could not survive the 6 month gap between shedding of eggs in spring and infection of eels in early winter outside of a host. Eels could not be infected directly with L2, nor could a range of common freshwater invertebrate species. Third stage larvae (L3) resembling P. tenerrima were found frequently and abundantly in the swimbladder of minnows Phoxinus phoxinus from several localities throughout the year and were able to survive in this host in the laboratory for at least 6 months. Third stage larvae identical to these larvae were recovered from minnows experimentally fed L2 of P. tenerrima, and eels infected experimentally with naturally and experimentally infected minnows were found to harbour fourth stage larvae (L4) and juvenile P. tenerrima in their intestines. Finally, the whole life cycle from eggs to adult was completed in the laboratory, confirming that minnows are an obligate intermediate host for P. tenerrima.

scholarly journals Human gnathostomiasis: a neglected food-borne zoonosis

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Guo-Hua Liu ◽  
Miao-Miao Sun ◽  
Hany M. Elsheikha ◽  
Yi-Tian Fu ◽  
Hiromu Sugiyama ◽  
...  
Keyword(s):  
Ecological Factors ◽  
Developed Countries ◽  
Host Immunity ◽  
Treatment Control ◽  
Social Ecological ◽  
Food Borne ◽  
Third Stage ◽  
Parasite Biology ◽  
Etiological Agents ◽  
And Control

Abstract Background Human gnathostomiasis is a food-borne zoonosis. Its etiological agents are the third-stage larvae of Gnathostoma spp. Human gnathostomiasis is often reported in developing countries, but it is also an emerging disease in developed countries in non-endemic areas. The recent surge in cases of human gnathostomiasis is mainly due to the increasing consumption of raw freshwater fish, amphibians, and reptiles. Methods This article reviews the literature on Gnathostoma spp. and the disease that these parasites cause in humans. We review the literature on the life cycle and pathogenesis of these parasites, the clinical features, epidemiology, diagnosis, treatment, control, and new molecular findings on human gnathostomiasis, and social-ecological factors related to the transmission of this disease. Conclusions The information presented provides an impetus for studying the parasite biology and host immunity. It is urgently needed to develop a quick and sensitive diagnosis and to develop an effective regimen for the management and control of human gnathostomiasis.

Nematophagous fungi in pasture: colonisation of sheep faeces and their potential for control of free-living stages of gastro-intestinal nematode parasites of sheep

2002 ◽  
Vol 42 (1) ◽  
pp. 7 ◽  
Author(s):  
F. S. Hay ◽  
J. H. Niezen ◽  
D. Leathwick ◽  
R. A. Skipp
Keyword(s):  
Laboratory Experiments ◽  
Nematophagous Fungi ◽  
Soil Nematodes ◽  
Arthrobotrys Oligospora ◽  
Free Living ◽  
Intestinal Nematode ◽  
Nematode Parasites ◽  
Fungal Propagules ◽  
Third Stage ◽  
Filter Type

Sheep faeces placed on a pasture in New Zealand in February and April were retrieved at intervals up to 28 days and examined for fungi that parasitise nematodes (nematophagous fungi). Monacrosporium haptotylum, Harposporium bysmatosporum, H. helicoides and a Nematoctonus sp. were present, respectively, in 37, 22, 13 and 8% of 283 samples retrieved in February and from 29, 14, 11 and 15% of 200 samples retrieved in April. Fungi entered faeces rapidly, being present in 35 and 54% of samples retrieved after 3 days in February and April, respectively. The ability of migrating soil nematodes to carry fungal propagules from soil into faeces was assessed in 2 laboratory experiments. Sheep faeces separated from soil by filters that allowed passage of both nematodes and fungi was colonised by H. helicoides more frequently than faeces on filters that excluded nematodes, indicating nematodes were vectors. However, Arthrobotrys oligospora, M. haptotylum and A. brochopaga occurred in faeces independently of filter type, indicating that these species grew into faeces. Two laboratory experiments examined the ability of nematophagous fungi, when inoculated into sheep faeces containing eggs of the gastro-intestinal nematode parasite Trichostrongylus colubriformis to reduce the number that developed to third-stage larvae. Monacrosporium gephyropagum, A. cladodes, A. conoides and A. oligospora reduced the number of third-stage larvae that emerged by 54–91% (P<0.05) in comparison to a control; however, M. haptotylum and H. bysmatosporum were ineffective. In a second experiment, several species of nematophagous fungi reduced the number of third-stage larvae that emerged by 41–96% (P<0.05) in comparison to a control, while others had no effect.

Resistance of chlamydospores of nematophagous fungi to the digestive processes of sheep in Mexico

1998 ◽  
Vol 72 (2) ◽  
pp. 155-158 ◽  
Author(s):  
R.D. Llerandi-Juárez ◽  
P. Mendoza-de Gives
Keyword(s):  
Oral Administration ◽  
Haemonchus Contortus ◽  
Corn Meal ◽  
Corn Meal Agar ◽  
Duddingtonia Flagrans ◽  
Free Living ◽  
Oral Inoculation ◽  
Third Stage ◽  
Mexican Isolate ◽  
Digestive Processes

AbstractFollowing oral administration to sheep, chlamydospores of a Mexican isolate of Duddingtonia flagrans (FTHO-8) survived passage through the digestive tract and subsequently grew on corn meal agar plates. The fungus was able to catch and destroy free-living nematodes and third-stage larvae of Haemonchus contortus added to these plates. Chlamydospores of Arthrobotrys sp. showed a poor resistance to the digestive processes of sheep, although conidia of A. superba survived following oral inoculation in one of two animals.

The bionomics of the free-living larvae and the transmission of Dictyocaulus filaria between lambs in North-East England

1976 ◽  
Vol 50 (2) ◽  
pp. 79-89 ◽  
Author(s):  
G. J. Gallie ◽  
V. J. Nunns
Keyword(s):  
Survival Time ◽  
Late Spring ◽  
Clinical Disease ◽  
Free Living ◽  
Rate Of Development ◽  
The Third ◽  
North East ◽  
Third Stage ◽  
Different Seasons ◽  
Autumn And Winter

AbstractThe bionomics of the free-living larvae of Dictyocaulus filaria on pasture, and the transmission of infection between lambs, were studied during different seasons of the year m North-East England.The rate of development of first-stage larvae to the third stage took 4–9 days in late spring and summer, 1½–4 weeks in autumn and 5½–7 weeks in winter. The proportion of first-stage larvae developing to the third stage ranged from 10–28% in autumn and winter, and 2–25% in spring and summer. The rate of mortality of the third-stage larvae was approximately logarithmic in nature, although the survival time was shorter in spring and summer than in autumn and winter. Third-stage larvae were able to survive from autumn until the spring of the following year in sufficient numbers to perpetuate transmission but not to cause clinical disease.

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