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1.
Lynnath E. Beckley 《African Zoology》2013,48(3):187-192
The larval development of the southern African endemic sparid Spondyliosoma emarginatum is described and illustrated from specimens collected in Algoa Bay and the Swartkops, Sundays and Swartvlei estuaries of the Cape Province. S. emarginatum has demersal eggs. Preflexion larvae are moderately elongate (BD = 18–23% BL) with body depth increasing to 31 % BL in postflexion stages. The head is rounded and the snout blunt but becomes more elongate in postflexion stages. There are short spines on the preoperculum. Flexion occurs at about 6 mm BL and postflexion larvae are characterized by distinct medio-lateral pigmentation. Osteological development is described from a series of cleared and stained specimens. All fins have the adult complement of spines and rays by 12 mm BL. The larvae of S. emarginatum are compared with those of the European S. canthurus and other southern African sparids. 相似文献
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S. Ku&#;ir Z. Kozari&#; E. Gjur&#;evi&#; B. Ba&#;dari&#; Z. Petrinec 《Anatomia, histologia, embryologia》2009,38(5):351-354
Garfish, Belone belone (Linnaeus, 1761) is an elongate, slander fish inhabiting the Eastern Atlantic and Mediterranean Sea. These fish from the Belonidae (Actinopterygii) family have important commercial value for Croatian fisheries. Samples for research were collected from experimental hatching in the Novigrad Sea. Preparation techniques included fixation in buffered formalin, trypsin clearing and staining with alcian blue and alizarin red. As little is known of garfish osteology and bone morphology, the main goal of this study was to describe ossification process in garfish fry. At hatching, no skeletal structure is present. Newly-hatched larvae also had no osteological elements. Ossification started at 7 day post-hatching (DPH) [total length (TL) 18 mm] with head bones and vertebral neural arch. Head skeleton continued to develop mostly over the period from 7 to 10 DPH. At 21 DPH (TL 49 mm), ossification process seemed to be finished, but it was not possible to distinguish borders of all bones. The primary interest of our research was to understand the growth dynamics as well as transformation of supporting body elements from cartilage to bone. At the end, developmental characteristics and functional aspects of this formation in different fish species are discussed. 相似文献
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《African Zoology》2013,48(2):240-251
This paper describes the morphology and ecology of the larvae and early juveniles of two common gobiids in warm temperate South African estuaries. The early developmental stages of Glossogobius callidus and Redigobius dewaali were collected during plankton surveys in seven permanently open and five intermittently open estuaries along southeastern South Africa. Larval G. callidus have a characteristic ventral row of pigment that extends from the cleithral symphysis along the ventral midline of the tail to the end of the caudal peduncle; notochord flexion takes place at the yolk-sac stage, between 3 and 4 mm BL. Larval R. dewaali are characterized by having two very large stellate melanophores on the ventral surface of the trunk and tail, and internal pigment between the snout and hindgut; notochord flexion takes place between 4 and 6 mm. Body lengths at settlement for G. callidus and R. dewaali are 13 mm and 16 mm, respectively. G. callidus and R. dewaali dominate the larval gobiid catch in warm temperate estuaries. Estuary type and freshwater input played a defining role in the occurrence of larvae of these, often sympatric, species in temperate estuaries. Larval G. callidus occurred in both permanently open and intermittently open estuaries, and were most abundant in mesohaline regions over the spring/summer period. By contrast, larval R. dewaali occurred exclusively in permanently open estuaries and were more prevalent in the fresh and oligohaline regions in autumn. Larvae of both species were more prevalent in freshwater-rich estuaries. Densities of G. callidus and R. dewaali peaked at 101 and 3829 larvae per 100 m3respectively. The usefulness of using the early stages of these gobiids as indicators of estuarine health based on their specific and often prolific estuarine occurrence is discussed. 相似文献
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Between 10 and 25% of the Dictyocaulus arnfieldi larvae excreted in faeces from a naturally infected donkey were harvested as infective stages from faecal cultures by means of Pilobolus fungi. The faeces were collected between 24 and 56 hours after drenching the donor animal with Pilobolus spores and kept at 16 +/- 2 degrees C. Most larvae were collected between the 5th and the 8th day of culturing during which period fructification and sporangium discharge also peaked. The sporangia and the adhering larvae were collected in Petri dishes inserted between the faecal mass and a light source. All recovered larvae were viable. A mean larval length of 368 microns (range 312-440 microns) and width of 14.6 microns (range 12-20 microns) was recorded for the infective stage. The method was found suitable for the recovery of infective stages for experimental purposes. The authors suggest that the Pilobolus mechanism play an important part in the spread of equine lungworm infection under field conditions similar to the situation in bovine lungworm (Dictyocaulus viviparus) infection. 相似文献
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Dung beetles as detritivores insects, naturally use feces of vertebrates as foods and reproduction beds. This leads to frequent contacts between dung beetles and parasitic helminths. The current study was carried out to assess infections of dung beetles with larval stages of helminths in rural areas of Taleqan County, Alborz Province, Iran. A total number of 200 dung beetles were collected randomly in June 2017 from the highlands of Taleqan County. Beetles were dissected in normal saline and carefully studied using a stereomicroscope. Morphological characteristics of the recovered larvae were drawn using a camera lucida equipped microscope at 400× magnification. Then, genomic DNAs of the recovered larvae extracted and PCR amplifications of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene were carried out and the amplicons were sequenced. All collected dung beetles identified as Scarabaeus armeniacus from the Scarabaeidae family (55.5 % were male and 44.5 % female). Three females of the beetles have been found to be naturally infected with the third stage larvae of Spirocerca lupi. The average length and width of the larvae were 2.95 (2.81–3.15; CI 95 %) and 0.12 (0.1–0.15; CI 95 %) mm, respectively. The phylogenetic analysis showed that S. lupi belonged to a clade within the Spirocercidae family. In the current study, S. armeniacus introduced as a potential biological vector for transmission of S. lupi to vertebrates in the region. To the best of the authors’ knowledge, this is the first report on the larval stages of S. lupi in S. armeniacus. 相似文献
7.
The egg and larval development of the Cape silverside, Atherina breviceps, are described and illustrated from material collected in the Swartvlei estuary. The eggs are spherical, 1,40-1,65 mm in diameter, with 6-12 uniformly spaced chorionic filaments attached at both ends to the chorion. TTie latter condition and the small size of the eggs are unique among the Atherina species. The larvae examined (5,1-15,7 mm) are elongate, have a yolk sac at hatching and are characterized by distinct body pigmentation and a prominent gas bladder. Flexion occurs between 7,6-11,2 mm, all fin elements are formed by 15,7 mm and scales develop by 20,0 mm. We compare the larval development of A breviceps with that of other atherinids and discuss the spawning of this species and the seasonal occurrence of larvae along the southern coast of Africa. 相似文献
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After foaling, 6 mares and their foals were placed on equine parasite-free pastures. Observations of fecal nematode eggs and pasture larvae indicated peak cyathostome egg production occurred in late August and early September, with greatest numbers of larvae on the forage appearing during October. Two foals were necropsied for parasitologic evaluations at approximately 155 days of age. Both had approximately 100,000 adult cyathostomes, mostly Cylicostephanus longibursatus, Cylicocyclus nassatus and Cyathostomum catinatum. However, there were nearly 7 times more cyathostome larvae (189,004) in the foal necropsied in October, during the autumn rise in pasture larval populations, than in the foal examined in September (27,354). 相似文献
11.
Oestrosis, the nasal myiasis of sheep and goats, is caused by the larvae of Oestrus ovis L. 1758 (Diptera, Oestridae) that develop from the first to the third stage larva in the nasal cavities and frontal sinuses of affected animals. The authors report the results of an epidemiological study of oestrosis of sheep in Sardinia, Italy. Heads of 6-month to 10-year-old Sardinian sheep (n=566) from 124 free-ranging flocks were examined for the presence and location O. ovis larvae from December 1996 to November 1997. Larvae were collected, counted, and larval stages were identified. O. ovis larvae were found in 100% of examined flocks and in 91% (514/566) of examined sheep. The monthly prevalence ranged from 69% in May to 100% in July. First stage larvae were found in 82% (463) of all heads examined, second stage larvae in 65% (367) and third stage larvae in 10% (56). The majority of sheep harboured first stage larvae, with prevalences of over 80% throughout most of the study period. The prevalence of O. ovis found in this study of Sardinian sheep is the highest reported in the Mediterranean area. The high percentage of first stage larvae found throughout the entire study period may be due to a brief period of decreased rate of larval maturation, in particular in December 1996 (96%) and January-October 1997 (94%). Third stage larvae were consistently present, often however, with extremely low prevalences compared to total larval burden. 相似文献
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Nejedli S Kozariá Z Kantura VG Petrinec Z Zobundzija M Sarusiá G Susiá V 《Veterinary research communications》2006,30(5):523-529
The body length and diameter of muscle fibres from the right hypaxial tail myomeres were measured in 100 sea bass larvae (Dicentrarchus labrax, L.) at ages of 40 to 90 days, from a fish farm in Croatia. The larvae were kept at a temperature of 19-20 degrees C and fed with standard feed for their respective ages. Body lengths of larvae 40-90 days old varied from 8 to 42 mm, increasing significantly in 10-day intervals (p < 0.001), except between days 50 and 60 when there was no increase in the body length. The measured diameters of muscle fibres ranged from 10 to 80 microm, the mean value increasing except between days 50 and 60. The fibre diameter in larvae aged up to 60 days was 10-40 microm, while that in larvae older than 70 days was 51-80 microm. In 90-day-old larvae there were no fibres of 10-20 microm in diameter; however, the number of fibers of 61-80 microm diameter increased. A statistically significant concordance was determined between the body length and fibre diameter of larvae 70 to 90 days old. Between days 50 and 60, arrested growth of the larval body and corresponding decrease in fibre diameter was observed. From day 45 until days 59, larvae were fed with Artemia nauplii and microparticles of formulated diets. From the day 60, minced fish was added to formulated diets. This change in diet probably resulted in the observed growth arrest. 相似文献
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The objective of this study was to determine certain aspects of the biology of Rhipicephalus (Boophilus) decoloratus larvae under laboratory and field conditions. Larvae allowed 48 h to select a vertical questing substrate preferred 90 cm rods in length to those of 60 or 30 cm, while in a separate experiment migration from rods 5 cm or 25 cm in length to rods 45 cm in length continued between 48 h and 72 h after larval release. Hatching of the larval progeny of engorged female ticks exposed to ambient field temperatures during the period June to August, occurred synchronously during the third or fourth week of November. With a single exception, larvae that hatched during November and between April and July survived for 38 days or longer, while those that hatched from December to March survived for 31 days or less. Questing larvae were present on vegetation throughout the year, with most being recovered during January and February. Parasitic larvae were present on cattle from October to May with most being collected during January and February. 相似文献
14.
Losson B Kervyn T Detry J Pastoret PP Mignon B Brochier B 《Veterinary parasitology》2003,117(1-2):23-28
Between June 1998 and February 2002, 709 red foxes killed in Wallonia (south of Belgium) were available for parasitological examination of the gut. The identification of Echinococcus multilocularis was based on morphological data. E. multilocularis adults were observed in 20.2% of the animals. The analysis of data revealed marked differences between the geological areas of Wallonia; the highest prevalence (33%) was found in the Ardenne and the lowest (0%) on the Plateau de Herve. Host gender and the collection season had no effect on the prevalence. However, the latter was significantly higher in juveniles (<8 months of age). The geographical distribution of E. multilocularis in Belgium is much wider than originally thought. 相似文献
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Separate controlled trials were conducted to evaluate the efficacy of two formulations of moxidectin (1% non-aqueous injectable solution and 0.5% pour-on (Cydectin) against larval or adult stages of Oesophagostomum radiatum and Trichuris discolor infecting cattle. Fifty-three strongylate-free dairy breed steer calves were obtained from commercial sources. After a brief acclimation period, calves were randomly divided into two pools to evaluate the efficacy of the moxidectin formulations against targeted larval (n = 27 calves) or adult (n = 26 calves) parasites. Calves in the larvacidal trial were inoculated on Day -16 relative to treatment with approximately 1000 embryonated Trichuris spp. eggs and approximately 640 infective Oesophagostomum spp. larvae. Calves were allocated by lottery to one of three treatment groups (n = 8 per group), which included: Group 1--moxidectin 0.5% pour-on (0.5 mg/kg body weight (BW)) applied topically; Group 2--moxidectin 1% non-aqueous injectable (0.2 mg/kg BW) administered subcutaneously; Group 3--untreated controls. Treatments were administered on Day 0 and calves were housed by group with no contact among animals of different treatments. Three sentinel calves were necropsied on Day 0 of the larvacidal trial to assess viability of larval inocula. On Days 14, 15 and 16 after treatment, calves were euthanatized (two or three from each group per day) and samples of gut contents were collected for determination of total worm counts. On Day -63 relative to treatment, calves in the adulticidal efficacy trial were inoculated with approximately 1000 embryonated Trichuris eggs and then on Day -35 with approximately 2500 infective Oesophagostomum spp. larvae. Fecal samples were collected on Day -7 and the 24 calves with the highest egg counts were assigned by lottery to the following three treatment groups (n = 8 per group): Group 4--moxidectin 0.5% pour-on; Group 5--moxidectin 1% injectable; Group 6--untreated controls. Details of experimental treatments, calf housing and necropsy scheduling were similar to the larvacidal trial. In both the larvacidal and adulticidal trials, inocula contained a variety of parasites in addition to the targeted species. Based on geometric means, both moxidectin 0.5% pour-on and moxidectin 1% non-aqueous injectable significantly reduced (P < 0.05) numbers of Oesophagostomum spp. and Trichuris spp. with anthelmintic efficacies of >99% when used against adult or larval stages of infection. In addition, both formulations of moxidectin demonstrated >95% efficacy (P < 0.05) against larval stages of Strongyloides papillosus. The pour-on formulation had >97% adulticidal and larvacidal efficacy against Cooperia spp. females, while the injectable product was effective against female Cooperia spp. larvae and Cooperia oncophora adult males. 相似文献
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Evaluation of the effects of selamectin against adult and immature stages of fleas (Ctenocephalides felis felis) on dogs and cats 总被引：2，自引：0，他引：2
McTier TL Shanks DJ Jernigan AD Rowan TG Jones RL Murphy MG Wang C Smith DG Holbert MS Blagburn BL 《Veterinary parasitology》2000,91(3-4):201-212
The adulticidal, ovicidal, and larvicidal effects of selamectin against flea (Ctenocephalides felis felis) infestations on dogs and cats were evaluated in a series of seven controlled and masked studies (three in cats, four in dogs). Animals were randomly allocated to treatment with either selamectin at a minimum dosage of 6mgkg(-1) in the commercial formulation or one of two negative-controls (0.9% NaCl solution or the vehicle from the commercial formulation). Treatments were administered topically in a single spot on the skin at the base of the neck in front of the scapulae. Speed of kill, measured by flea comb counts at 12h intervals during the 48h immediately following a single treatment on day 0, was evaluated in two studies. One study was in dogs and the other in cats, and each animal was infested with approximately 100 unfed viable adult fleas prior to treatment. Reductions in geometric mean flea counts for selamectin compared with saline were >98% between 24 and 36h after treatment in dogs, and between 12 and 24h after treatment in cats (P< or =0.0006). Efficacy in reducing flea egg hatch and larval development was evaluated in four studies, in which dogs and cats were treated once on day 0 and then repeatedly infested with approximately 600 fleas. Flea eggs were collected approximately for 72h after each infestation, on days 3, 7, 14, 21, and 30, counted, and cultured to determine their hatchability and subsequent larval development. Compared with the vehicle, selamectin was highly effective in reducing flea egg hatch (>92% in cats) and larval development (> or =95% for dogs and cats), and emergence of adults (97.8-100% for dogs, 85.6-100% for cats) for 30 days. Effects of exposure to hair coat debris were investigated in a study with dogs treated once on day 0 and repeatedly infested with 100 adult fleas. Debris (dander, flea faeces, hair, scales) was collected on days 1, 7, 14, 21, and 30 and added to normal flea eggs or larvae for incubation. Compared with debris from vehicle-treated dogs, debris from selamectin-treated dogs was highly effective in preventing egg hatch (>96%), in killing larvae (>98%) and in preventing larval development to adults (>99%) (P相似文献
17.
Colwell DD 《Veterinary parasitology》2001,99(3):231-239
Stage specific survival of larvae and pupae of the common cattle grub, Hypoderma lineatum de Villers, was compared in cattle artificially infested with larvae delivered by subcutaneous injection as a single infestation of 100 larvae, in trickle infestations of either two doses of 50 larvae, separated by 15 days, or in four doses of 25 larvae, separated by 9, 6, and 6 days, respectively. The duration of the migratory and 'warble' phases were also compared between treatments. The kinetics of the antibody response was monitored throughout the larval development by ELISA. No difference was noted in the level of antibodies among the three treatments. Mortality of first-instars differed among the infestation groups with mortality in the single pulse infestation group相似文献
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在2003年3月~2005年3月间,分4次对0.5~6.5年龄段已知年龄的人工饲养的扬子鳄头长(HL)、头宽(HW)、吻眼间距(SE)和眼间距(EE)这4个头部形态参数和体长进行测量。在所测量的各年龄段中,鳄的体长范围互有重叠,不适合作为鳄年龄鉴定的指标。以体长作为协变量的协方差分析表明:头长在0.5龄与2.5龄间(P=0.173)无显著性差异,头宽在0.5龄与1.5、2.5和3.5龄间(P=1.171、P=1.013、P=1.533)以及1.5龄与2.5龄间(P=0.159)无显著性差异;而头长和头宽在其他年龄段间,以及吻眼间距和眼间距在所有年龄段间均有极显著性差异;同一批鳄生长一年后,即1.5龄长到2.5龄,2.5龄长到3.5龄,4.5龄长到5.5龄,其头部形态的4个参数都有显著性变化,而在不同年份生长的同龄鳄间,如在1.52、.5和5.5龄的同龄鳄间,其吻眼间距都存在显著性差异,头长和头宽在2.5和5.5龄时具有显著性差异,眼间距却都无显著性差异,保持着稳定的状态;在同龄的不同性别鳄中,如4.5龄的雌雄鳄间,眼间距无显著性差异,即该参数不存在性别的差异。经比较分析显示,扬子鳄的年龄不宜通过体长、头长、头宽和吻眼间距等参数进行确定,而与眼间距值存在着对应关系。这一研究结果为野生扬子鳄种群的结构变化建立动态模型,为野生扬子鳄的性成熟年龄及生育年龄做出准确的判断,对鳄的引种贸易和科研中的样本筛选等具有重要的指导作用。 相似文献
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In a series of laboratory studies the optimum conditions for the development and survival of the free-living stages of strongyle parasites occurring in horses in tropical north Queensland were determined. No differences in behaviour were noted between the strongyle species. Development to the infective stage occurred only between 10 and 35 degrees C. The rate was affected by temperature, taking 15-24 days and 3 days, respectively, at the lowest and highest temperatures for the developing stages to reach the infective third stage. Yields of infective larvae were very low outside the range 20-33 degrees C, and were highest at 28 degrees C. Survival of infective larvae was good between 20 and 33 degrees C, and large numbers were recovered after 3 months in faeces incubated at 20-28 degrees C. At 33 and 37 degrees C larval survival was affected by the moisture content of the faeces, with infective larvae surviving better in dry than in moist faeces; even a residual moisture level of 40% significantly reduced the number of larvae recovered from faeces incubated at 37 degrees C for 1 month. Moisture also affected larval development, especially at the higher temperatures of 25-39 degrees C. When faecal moisture content fell to less than or equal to 20% by 3 days, larvae which had not yet reached the infective stage were still pre-infective at 7 days, while all larvae in faeces with adequate moisture had reached the infective third stage. It was not possible to determine the critical faecal moisture level below which larval development ceased, however, 28 degrees C (range 25-33 degrees C) was found to be the optimum temperature. Larval development was very rapid and yields of infective larvae highest at this temperature. 相似文献
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Dowdall SM Matthews JB Mair T Murphy D Love S Proudman CJ 《Veterinary parasitology》2002,106(3):225-242
Equine clinical larval cyathostominosis is caused by simultaneous mass emergence of previously inhibited larvae from the mucosa of the colon. Clinical signs include diarrhoea, colic, weight loss and malaise, and in up to 50% of cases, the disease results in death. Cyathostominae spend a large part of their life cycle as larval stages in the intestinal mucosa. Definitive diagnosis is difficult due to the lack of diagnostic methods for pre-patent infection. In the present study, the enzyme-linked immunosorbent assay (ELISA) was used to investigate isotype responses to larval cyathostominae somatic antigen. Measurement of anti-larval IgG(T) responses appeared to have the most immunodiagnostic potential. An increase in IgG(T) response was detected to crude larval antigen by 5 weeks post-infection (PI) in individual infected ponies. Subsequently, IgG(T) responses to larval and adult somatic extracts were examined by Western blotting using sera from experimentally-infected horses and helminth-naive animals (n=6). Two antigen complexes, designated A and B, in larval somatic antigen were recognised specifically by the infected animals by 7 weeks PI. Sera taken from 23 endemically-infected animals, whose cyathostominae burdens had been enumerated, were also used to identify putative diagnostic antigens. Eighteen horses had positive mucosal worm burdens (range 723-3,595,725) and all but two of these animals had serum IgG(T) antibody specific to either complex. Moreover, IgG(T) responses specific to antigen complexes A and B were absent in all five parasite negative horses that were tested. Serum IgG(T) responses to either of the two complexes were identified in five clinical cases tested. IgG(T) responses to adult antigen somatic extracts were more heterogeneous, with no clear pattern between experimentally-infected ponies and helminth-free controls. The results indicate that increases in serum IgG(T) to mucosal larvae occur in the pre-patent period and that two antigenic complexes within somatic preparations of these stages have immunodiagnostic potential. 相似文献