Development and transmission of Oswaldocruzia pipiens Walton, 1929 (Nematoda: Trichostrongylidae) in amphibians

1978 ◽  
Vol 56 (5) ◽  
pp. 1026-1031 ◽  
Author(s):  
M. R. Baker
Keyword(s):  
Early Development ◽  
Rana Sylvatica ◽  
Skin Penetration ◽  
Prepatent Period ◽  
Infective Stage ◽  
Anterior Portion ◽  
Infective Larvae

Development of Oswaldocruzia pipiens was similar to that of other trichostrongyles which have been studied. First-stage larvae have a valved, rhabditiform oesophagus. Infective larvae are ensheathed and have a strongyliform oesophagus. Development to the infective stage occurred in faeces and transmission was by skin penetration. In frogs, early development occurred on the mucosa of the stomach: worms then migrated to the anterior portion of the intestine. The prepatent period was 14–18 days at 14–18 °C. Patent infections developed in experimentally infected tadpoles of Rana sylvatica. However, there was no evidence of natural infections in tadpoles. There were no significant fluctuations of prevalence and intensity between April and October, 1976 and 1977, in transformed R. sylvatica from a single marsh near Guelph, Ontario. Transmission apparently took place during spring and throughout the summer. Young frogs acquired infections rapidly.

Migration, growth, and morphogenesis of Dracunculus insignis (Nematoda: Dracunculoidea)

1975 ◽  
Vol 53 (2) ◽  
pp. 105-113 ◽  
Author(s):  
Vincent Frederick Joseph Crichton ◽  
Mary Beverley-Burton
Keyword(s):  
Quantitative Data ◽  
Subcutaneous Tissue ◽  
Abdominal Cavity ◽  
Final Host ◽  
Prepatent Period ◽  
Infective Stage ◽  
Infective Larvae ◽  
Third Stage ◽  
Migratory Route

Larvae of Dracunculus insignis developed to the infective stage in experimentally infected Cyclops vernalis and C. bicuspidatus thomasi kept at 24 C. The first molt occurred at 8–9 days and the second at 13–16 days. Second- and third-stage larvae are briefly described. Infective larvae were administered to raccoon (Procyon lotor) and mink (Mustela vison) and necropsies were performed at predetermined intervals for the determination of the migratory route. In raccoon, third-stage larvae were recovered from the gut wall and mesentery of the abdominal cavity on the 1st day. Larvae were found in the intercostal muscles by the 5th day and in the subcutaneous tissue of the thorax and abdomen by the 7th day. Development to fourth stage was complete by the 19th day. Sexual differences were apparent by the 34th day and worms were present in subcutaneous tissue of the thorax, abdomen, and inguinal region. Male worms were mature at 60 days and females at 65–70 days. Larvigerous females were found in the extremities as early as 120 days post infection. The prepatent period was 354 (309–410) days. Similar results were obtained from mink. Quantitative data on the distribution of worms in various locations within the final host at different times after infection are included.

The free-living and parasitic development of Rhabdias spp. (Nematoda: Rhabdiasidae) in amphibians

1979 ◽  
Vol 57 (1) ◽  
pp. 161-178 ◽  
Author(s):  
M. R. Baker
Keyword(s):  
Rana Sylvatica ◽  
Skin Penetration ◽  
Body Cavity ◽  
The Body ◽  
Free Living ◽  
Infective Larvae ◽  
Ecological Barriers ◽  
In The Wild ◽  
Paratenic Hosts ◽  
Similar Growth

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.

The ecology of immature phases of Trichostrongyle nematodes: II. The effect of climatic factors on the availability of the infective larvae of Trichostrongylus retortaeformis to the host

Parasitology ◽  
1948 ◽  
Vol 39 (1-2) ◽  
pp. 26-38 ◽  
Author(s):  
H. D. Crofton
Keyword(s):  
Climatic Factors ◽  
Faecal Pellet ◽  
Cold Weather ◽  
Maximum Temperature ◽  
Infective Stage ◽  
Faecal Pellets ◽  
Infective Larvae ◽  
High Death ◽  
Maximum Temperatures ◽  
Rate Of Evaporation

1. Eggs and larvae of Trichostrongylus retortaeformis were used.2. The rate of hatching of eggs was shown to be mainly related to temperature. From November to March, when maximum temperatures were below 50° F., there was no hatching. When maximum temperatures of 50–55° F. occurred eggs hatched on or before the fifteenth day, but never during the first 8 days. Eggs hatched in 8 days or less when maximum temperatures of 60–80° F. occurred.3. When the rate of evaporation in the air was high, eggs still hatched and reached the infective stage, the grass blades reducing the rate of loss of moisture from the faecal pellet. Laboratory experiments show that eggs may not develop to the infective stage if the faecal pellets are on a grassless portion of the pasture. This is most likely to occur when the rate of evaporation is high and the temperature low.4. Hatching may be delayed by cold conditions, but some eggs remain viable for long periods and they hatch when the temperature rises. Eggs passed by the host in the autumn can survive a cold winter and hatch in the spring, but eggs passed during the coldest period die.5. During periods when the maximum temperature never exceeded 55° F., little or no migration of larvae occurred. When temperatures rose above 55° F. the number of larvae migrating increased; but rise of temperature was associated with increase in the rate of evaporation. High rates of evaporation reduced the number of larvae migrating on the grass blades.6. Some infective larvae died soon after exposure on grass plots, but a small number survived long periods. In cold weather some larvae were still alive after 20 weeks. A high death-rate occurred in warm weather. A large proportion of the larvae died during periods in which the rate of evaporation was high; in one of these periods 95% of the larvae were dead at the end of 4 weeks' exposure.7. The number of larvae on grass blades of a pasture was shown to be dependent, at any time, upon the climate at that time, and upon past conditions which had influenced hatching and survival:

Some Observations on the Transmission of Bacteria by Infective Larvae of Nippostrongylus brasiliensis

1955 ◽  
Vol 29 (1-2) ◽  
pp. 27-32 ◽  
Author(s):  
H. M. Gharib
Keyword(s):  
Life Cycle ◽  
Definitive Host ◽  
Infected Host ◽  
Nippostrongylus Brasiliensis ◽  
Infective Stage ◽  
Natural Conditions ◽  
Larval Stages ◽  
Infective Larvae ◽  
External Development

It is well known that the first two larval stages in the life cycle of nematodes belonging to the superfamily Strongloidea, have a freeliving existence. During this time, the larva which hatches from the egg feeds actively, undergoes two moults and grows considerably before reaching the infective stage, when it is ready to invade a definitive host. Under natural conditions this external development takes place in the faeces, which have been deposited by the infected host on ground likely to be contaminated with various bacteria.

Some observations on the bionomics of Bunostomum phlebotomum, a hookworm of cattle

Parasitology ◽  
1946 ◽  
Vol 37 (3-4) ◽  
pp. 202-210 ◽  
Author(s):  
J. F. A. Sprent
Keyword(s):  
Local Environment ◽  
Skin Penetration ◽  
Dry Season ◽  
Egg Laying ◽  
Seasonal Incidence ◽  
Infective Larvae ◽  
Direct Exposure ◽  
Laboratory Assistant ◽  
Stock Farm ◽  
Methods Of Control

Investigations were carried out on the influence of the local environment on the preparasitic stages of B. phlebotomum and the following observations were made.1. The infective larvae are positively thermo-tropic and positively phototropic. These observations confirm those of Schwartz (1924). The larvae are not negatively geotropic and do not climb grass, but remain in the dung, gaining access to the host by adherence of the dung to the skin.2. Lack of air, such as would occur in tightly packed faeces; immersion of the faeces in water; temperatures below 10° C.; and lack of moisture, are all inhibitory to development. Infective larvae are resistant to at least 5 days‘ direct exposure to an atmosphere of relative humidity 75 at a temperature of 25° C.; in dry faeces they are resistant to 14 days‘ exposure to the same atmosphere.3. In Northern Nigeria desiccation is the most important inhibitory factor in development. The extreme dryness of the pastures in the dry season prevents development of the larvae and adherence of dung to the skin. Penetration of the skin of the host probably occurs only in the rainy season, maximal penetration probably occurring just after the rains are regularly established.4. The female lays 600 eggs in 12 hr. in the early rains, but the output of eggs by the females varies considerably throughout the year. It is greatest in the early rains and lowest in the later months of the dry season.5. The female hookworm burden of nomadic cattle fluctuates throughout the year. The maximum burden occurs in the later months of the dry season.6. Three factors, all probably bound up with a single factor, i.e. moisture, seem to influence the degree of pasture infectivity. (a) Inhibition of larval development; (b) failure of faeces to adhere to the skin; (c) fluctuation in the egg-laying rate of the female hookworms. The fluctuating pasture infectivity results in a fluctuating hookworm burden.7. The period of maximum hookworm burden in nomadic cattle more or less coincides with the period of incidence of a disease in Stock Farm cattle, associated with hookworm infestation.In the discussion an attempt is made to correlate these observations both in accounting for the seasonal incidence of ‘hookworm disease’ and in suggesting methods of control.This paper was written during the tenure of a Cooper Centenary Fellowship for which the author is indebted to the Council of the Veterinary Educational Trust. The writer's thanks are also due to his laboratory assistant in Nigeria, Mr R. A. O. Shonekan.

Mechanism of skin penetration byAncylostoma tubaeformelarvae

Parasitology ◽  
1975 ◽  
Vol 70 (1) ◽  
pp. 25-38 ◽  
Author(s):  
Bernard E. Matthews
Keyword(s):  
Skin Penetration ◽  
Larval Migration ◽  
Necator Americanus ◽  
Infective Larvae ◽  
Dermal Tissue ◽  
Epidermal Surface ◽  
Positive Results

Skin penetration by infectiveAncylostoma tubaeformelarvae has been investigated cinematographically and usingin vitrotechniques. The dermal tissue appears to cause little hindrance to larval migration but complete penetration through the skin from the dermal direction did not occur, although total penetration from the epidermal surface was frequently accomplished. No evidence could be found for enzymic secretions emanating from the worms under conditions that gave positive results fromNecator americanusandStrongyloides fülleborniinfective larvae. The results indicated thatA. tubaeformewas able to penetrate without the use of enzymic secretions and an alternative, mechanical mechanism for penetration is advanced.

Observations on the free-living stages of strongylid nematodes of the horse

Parasitology ◽  
1972 ◽  
Vol 64 (3) ◽  
pp. 461-477 ◽  
Author(s):  
C. P. Ogbourne
Keyword(s):  
Laboratory Experiments ◽  
Field Observations ◽  
Infective Stage ◽  
Free Living ◽  
Rate Of Development ◽  
Infective Larvae ◽  
Strongylus Vulgaris ◽  
Different Temperatures ◽  
Eggs And Larvae

Observations have been made on the development and survival of the free-living stages in faeces deposited out of doors at different times of year, and on the migration of infective larvae to the surrounding herbage. Laboratory experiments were performed to assist in the interpretation of the field observations. Studies were made on the rate of development to the infective stage in faeces kept at different temperatures. The rates at which eggs and larvae of Strongylus vulgaris, S edentatus, S. equinus and Trichonema nassatum developed on faecal-agar cultures at different temperatures were compared. Studies were also made on the effect of desiccation of faeces on the development and survival of the free-living stages. The results of these observations are discussed in relation to the development of herbage infestations on British pastures.

scholarly journals The influence of desiccation and UV radiation on the development and survival of free-living stages of cyathostomins under field and laboratory conditions

2008 ◽  
Vol 45 (1) ◽  
pp. 32-40 ◽  
Author(s):  
I. Langrová ◽  
I. Jankovská ◽  
J. Vadlejch ◽  
M. Libra ◽  
A. Lytvynets ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Field Experiments ◽  
The Other ◽  
Infective Stage ◽  
Free Living ◽  
Infective Larvae ◽  
Laboratory Conditions ◽  
Other Hand ◽  
Field And Laboratory Conditions

AbstractThe present work describing both laboratory and field experiments was performed to assess the effects of desiccation and UV radiation on the development and survival of free-living stages of equine cyathostomins.Cyathostomin larvae in horse faeces did not develop to the infective stage when faecal humidity levels dropped below 23 %, nonetheless solitary preinfective larvae were still recovered after 151 days (humidity 19.5 %). The development to infective stage after remoistening occurred for the last time after 54 days following desiccation.Preinfective stages are susceptible to the effects of the direct desiccation stage. The preinfective larvae were rapidly killed within one minute, the cyathostomin eggs within 5 hours. The numerous normal mobile infective larvae were encountered after 35 days of the desiccated period. The preinfective stage of cyathostomins also showed very little tolerance to direct sun radiation: most eggs were killed by the exposure within 3 hours and the preinfective larvae within 1 hour. The survival of infective larvae was, on the other hand, unaffected by sun radiation after 7 days (P < 0.05). However, desiccated infective larvae were then found to be susceptible to UV radiation, resulting in total mortalities after 5 days.

Biology of Monanema globulosa, a rodent filaria with skin-dwelling microfilariae

1983 ◽  
Vol 57 (3) ◽  
pp. 259-278 ◽  
Author(s):  
A. E. Bianco ◽  
R. Muller ◽  
G. S. Nelson
Keyword(s):  
Early Development ◽  
Pulmonary Arteries ◽  
Tissue Reaction ◽  
Prepatent Period ◽  
Rodent Model ◽  
The Body ◽  
Site Specific ◽  
Third Stage ◽  
Natural Hosts ◽  
The Mean

ABSTRACTMonanema globulosa (Nematoda: Filarioidea) was recovered from four species of rodents in Kenya, with a prevalence of up to 94% in the striped mouse, Lemniscomys striatus. The adult worms are site-specific to the pulmonary arteries and release sheathed microfilariae that travel via the blood to the skin. Densities of microfilariea in the ears (mf/mg) were five to eight times greater than in any other region of the body and were directly proportional to the number of adult worms present. Highest concentrations of microfilariae in the skin were reached after 100 to 200 days and low numbers persisted in most animals for approximately 500 days.Third-stage larvae from ticks (Haemaphysalis leachii) injected subcutaneously into jirds migrated widely through the body during early development. Moults occurred twice, after 5 to 10 days and 25 days, and the mean prepatent period was 75 (range 69 to 88) days. A mild eosinophilia developed which peaked after 29 days. Adults in the lungs provoked widespread and intense perivascular cuffing and more localized hypertrophy and fibrosis of the intima in arterioles. Dead adults caused granulomata which obliterated smaller vessels. Microfilariae in the skin elicited no local tissue reaction, but some which invaded the eyes caused a monocyte infiltration of the cornea. It is concluded that the parasite is well adapted to its natural hosts and that it has potential as a rodent model for human onchocerciasis because of the localization of microfilariae in the skin.

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