RESUMO
In Brazil there are several records of parasitic nematodes of fish with zoonotic potential, especially those belonging to the family Anisakidae. This study considers the morphology, morphometry and prevalence of Contracaecum in Astronotus ocellatus , fish consumed in the Amazon and sold as ornamental and it also performs a retrospective analysis of the diversity of fish with larvae of Contracaecum, in studies carried out in Brazil over a period of 90 years. 40 specimens of A. ocellatus were necropsied, and the nematodes were collected and fixed in 93 parts 70% ethyl alcohol, 5 parts formaldehyde, and 2 parts glacial acetic acid (AFA) for morphological analysis under light microscopy and scanning electron microscopy. Of the 40 fish collected during this work, 27 were parasitized by Contracaecum larvae with a total intensity of 150 larvae. Retrospective analysis of intermediate host diversity for Contracaecum larvae resulted in 16 orders, 49 families, 96 genera, 140 species and a hybrid morphotype. In the retrospective study, half of the fish were from freshwater, with the order Perciformes being the most representative, with 16 families, 30 genera and 37 species. In Brazil, the occurrence of larvae of Contracaecum in fish was reported in 15 of the 26 states, with Rio de Janeiro presenting the most information regarding fish harboring Contracaecum larvae.(AU)
No Brasil existem vários registros de nematóides parasitos de peixes com potencial zoonótico, especialmente aqueles pertencentes à família Anisakidae. Este estudo considera a morfologia, morfometria e prevalência de Contracaecum em Astronotus ocellatus, peixe consumido na Amazônia e vendido como ornamental, e também realiza uma análise retrospectiva da ictiofauna parasitada com larvas de Contracaecum, em estudos realizados no Brasil, durante um período de 90 anos. 40 espécimes de A. ocellatus foram necropsiados, e os nematóides foram coletados e fixados em 93 partes de álcool etílico 70%, 5 partes de formaldeído e 2 partes de ácido acético glacial (AFA) para análise morfológica em microscopia de luz e microscopia eletrônica de varredura. Dos 40 peixes coletados durante este trabalho, 27 estavam parasitados por Contracaecum, com intensidade total de 150 larvas. Análises retrospectivas da diversidade de hospedeiros intermediários para larvas de Contracaecum resultaram em 16 ordens, 49 famílias, 96 gêneros,140 espécies e um morfotipo híbrido. No estudo retrospectivo, metade dos peixes eram de água doce, sendo a ordem Perciformes a mais representativa, com 16 famílias, 30 gêneros e 37 espécies. No Brasil, a ocorrência de larvas de Contracaecum em peixes foi relatada em 15 dos 26 estados, com o Rio de Janeiro apresentando mais informações sobre peixes portadores de larvas de Contracaecum.(AU)
Assuntos
Animais , Rabditídios/anatomia & histologia , Rabditídios/crescimento & desenvolvimento , Rabditídios/parasitologia , Estudos Retrospectivos , Filogeografia , Zoonoses/diagnósticoRESUMO
A new species of the genus Diomedenema, a spiruromorph nematode, collected from the lung of Spheniscus magellanicus (Sphenisciformes) found on the southern coast of the state of Rio Grande do Sul, Brazil, is described. The new species is differentiated from the only previously described species of the genus, D. diomedeae Johston & Mawson, 1952, by males possessing a set of caudal papillae with three pairs of precloacal, two pairs of adcloacal and one pair of postcloacal papillae; precloacal papillae with the papillae of the first two pairs being closer to each other than those of the third pair; a longer and pointed tail in males; and females with the vulva at mid-body. This is the first report of a nematode infecting the lung of a sphenisciforme host.
Assuntos
Doenças das Aves/parasitologia , Infecções por Rhabditida/veterinária , Rabditídios/isolamento & purificação , Spheniscidae/parasitologia , Animais , Brasil , Feminino , Masculino , Rabditídios/classificação , Rabditídios/genética , Rabditídios/crescimento & desenvolvimento , Infecções por Rhabditida/parasitologiaRESUMO
Entomopathogenic nematodes (EPNs) of the families Steinernematidae and Heterorhabditidae have a symbiotic association with bacteria which makes them virulent against insects. EPNs have been mass produced using in vivo and in vitro methods, including both solid and liquid fermentation. This study assessed the effect of nematode inoculum age on the production of Steinernema feltiae in liquid, solid and biphasic processes. Several physical parameters were also assessed: the effect of medium viscosity, flask size and aeration speed on the recovery and yield of infective juveniles (IJs). Inoculum age treatments included inoculum liquid cultures that were 7, 14, 21 and 28 days old. Nematodes from the same inoculum were added to one liquid medium (liquid culture), one solid medium with bacteria previously grown in sponge (solid culture) and a variation of the solid medium (a biphasic culture), in which the bacteria were first grown in liquid and, then, soaked into the sponges, with the purpose of providing a more homogeneous bacterial culture before nematode inoculation. Experiments were conducted in Erlenmeyer flasks. Eight treatments were established involving combinations of three variables: two media (with and without 0.2% agar), two flask sizes (250 and 150 ml) and two agitation speeds (180 and 280 rpm). The study showed increases in nematode yield for liquid cultures, but not for solid or biphasic cultures, with the advance of the inoculum age up to 28 days of growth. Furthermore, the addition of 0.2% agar to the liquid medium and increasing the aeration rate by using larger flasks with higher agitation speed may increase nematode recovery and final yield. The experiments were conducted using shake flasks but the results may also be applicable for bioreactors.
Assuntos
Insetos/parasitologia , Rabditídios/crescimento & desenvolvimento , Animais , Meios de Cultura/química , Meios de Cultura/metabolismo , Rabditídios/metabolismo , Rabditídios/microbiologia , Xenorhabdus/crescimento & desenvolvimento , Xenorhabdus/metabolismo , Xenorhabdus/fisiologiaRESUMO
A nematode from the genus Steinernema was isolated in Zulia state (North-western, Venezuela). Morphological, morphometric and molecular studies indicated that this nematode belongs to the "bicornutum" group and is described herein as Steinernema goweni n. sp. Steinernema goweni n. sp. is characterised by morphometrics of its infective juveniles, with body length 640 (531-719) µm, pharynx length of 119 (109-126) µm, tail of 67 (59-89) µm, c ratio = 9 (6-11) and E% = 77 (48-94). First generation male specimens can be recognised by the shape and size of spicules (55 (50-57) µm long) and gubernaculum (35 (30-40) µm long), and %D value 42 (28-59), which is at the lower limit within the "bicornutum" group. The number of genital papillae in males is also distinctive for S. goweni n. sp. presenting up to 27 (13 pairs + 1) papillae in 15% of specimens. The phasmids can be seen in scanning electron microscopy in all stages, characters not previously reported within the "bicornutum" group. Phylogenetic analyses of the "bicornutum" group based on both ITS and D2D3 regions showed a clear separation of S. goweni n. sp. from the other species. In both analyses S. goweni n. sp. formed a strongly supported group of American species.
Assuntos
Insetos/parasitologia , Rabditídios/classificação , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Tamanho Corporal , Ecossistema , Feminino , Masculino , Tamanho do Órgão , Filogenia , Rabditídios/anatomia & histologia , Rabditídios/genética , Rabditídios/crescimento & desenvolvimento , VenezuelaRESUMO
The life cycle of four Steinernema species was observed in 4 insect micro-insect host species (less than 5mm long). Several parameters were measured: sex ratio of invading nematodes, percentages of host infection and offspring production, penetration rate of infective juveniles per insect and number of new generation of infective juveniles. All parameters varied among nematode species, micro-host species and application rates. All Steinernema species were capable to invade micro-insect hosts, however, invasion decreased as insect size decreased and as nematode species size increased. None of the nematode species achieved 100% mortality in the micro-hosts. Due to size differences in the nematode species, Steinernema glaseri was less capable of completing its life cycle and unable to invade smaller hosts whereas S. riobrave completed its life cycle in smaller hosts more frequently. The number of invading nematodes and the number of offspring produced had the same levels regardless of the nematode application rates, those results showed a maximum top in the number of individuals per micro-insect host. The offspring production in thrips species was only possible by endotokia matricida in S. riobrave. The sex of the invader nematodes also impeded the life cycle of S. affine because males colonized the entire body of the micro-insect host leaving no room for female invasion. The size of the host plays an irrefutable role in limiting the development of nematodes and it appears improbable that an entomopathogenic nematode population can persist in the soil without the presence of bigger insects.
Assuntos
Insetos/parasitologia , Rabditídios/fisiologia , Animais , Feminino , Interações Hospedeiro-Parasita , Insetos/anatomia & histologia , Estágios do Ciclo de Vida , Masculino , Rabditídios/crescimento & desenvolvimento , Razão de Masculinidade , Especificidade da EspécieRESUMO
In view of the need to combat the generalized spread of resistance in ticks to commercial acaricides, the objective of this study was to evaluate the action of entomopathogenic nematodes (Steinernema carpocapsae, strains Santa Rosa and ALL) on engorged female Anocentor nitens. Five ticks per Petri dish were exposed to concentrations of 500, 5,000, or 25,000 infective juveniles of S. carpocapsae for 72 h. After transferring the ticks to clean plates, biological parameters were analyzed. Related to strains Santa Rosa, the period of pre-oviposition (p = 0.0001), oviposition (p = 0.041), and the mass weight of eggs (p = 0.005) showed significant differences between the control group and treated group. When the strain ALL was tested, the control and treated groups differed between the periods of pre-oviposition (p = 0.001), oviposition (p = 0.001), and egg mass weight (p = 0.01). The egg mass conversion was less significant in the groups when exposed to strains Santa Rosa (p = 0.002) and ALL (p = 0.001) relative to the control. The efficacy of both entomopathogenic nematode strains used in this study was comparable to other biological control agents, showing their potential against A. nitens in the laboratory.
Assuntos
Dermacentor/parasitologia , Controle Biológico de Vetores/métodos , Rabditídios/crescimento & desenvolvimento , Animais , Dermacentor/fisiologia , Feminino , Oviposição/fisiologia , Óvulo/fisiologiaRESUMO
There have been studies of the compatibility between entomopathogenic nematodes and insecticides commonly used to control crop pests, but this same approach has not been widely studied regarding the control of ticks. Therefore, this work examines the association between a species of entomopathogenic nematode, Steinernema glaseri, and an organophosphate acaricide to control the cattle tick Rhipicephalus microplus. Engorged females were separated into 12 groups, with ten repetitions each, immersed for 5 min in varied concentrations of acaricide (commercial dose and one-half, one-fourth, one-eighth and one-sixteenth of that dose), associated or not with the nematodes, maintained under controlled conditions. There were two control groups, one containing nematodes and water and the other only water. The absence of egg laying and significant reduction in the survival period of the females in the nematode treatments associated with the lowest acaricide doses demonstrated the compatibility between the two agents. We observed the presence of S. glaseri adults on the cuticle of the females in the treatments with one-eighth and one-sixteenth the commercial dose. These results indicate greater efficacy of the treatments with lower acaricide concentrations in association with S. glaseri, with less environmental impact, reduced costs and less resistance selection pressure on the tick populations.
Assuntos
Inseticidas/farmacologia , Organofosfatos/farmacologia , Controle Biológico de Vetores , Rabditídios/crescimento & desenvolvimento , Rhipicephalus , Animais , Feminino , Oviposição , Rhipicephalus/efeitos dos fármacos , Rhipicephalus/crescimento & desenvolvimento , Rhipicephalus/parasitologia , Rhipicephalus/fisiologia , Especificidade da EspécieRESUMO
The submerged culture of the entomopathogenic nematode Steinernema carpocapsae and its symbiotic bacterium, Xenorhabdus nematophila, was carried out in orbitally agitated bottles using a culture medium containing whey (in grams per litre: 500 whey, 20 yeast extract, 10 dried egg yolk-food grade, 3 sodium chloride, 37 corn oil-food grade). Maximum total viable nematode concentrations of 198,333ml(-1) were achieved within fermentations of 24 days with 64% of the nematode population within the infective juvenile stage (IJ) (126,666ml(-1)) at the end. The kinetics of the bioprocess was well modelled using the four-parameter Sigmoidal model and the corresponding maximum specific rates of nematode production (0.47 day(-1)), carbohydrates consumption (0.0008g(carbohydrates)g(nematodes)(-1)day(-1)) and nitrogen consumption (4.44g(nitrogen)g(nematodes)(-1)day(-1)) are first proposed. Besides, X. nematophila appears to have the capacity of lactose hydrolysis.
Assuntos
Meios de Cultura/metabolismo , Proteínas do Leite/metabolismo , Nematoides/crescimento & desenvolvimento , Rabditídios/crescimento & desenvolvimento , Xenorhabdus/crescimento & desenvolvimento , Animais , Técnicas Bacteriológicas/métodos , Biomassa , Carboidratos/química , Técnicas de Cocultura/métodos , Meios de Cultura/química , Fermentação , Cinética , Lactose/química , Lactose/metabolismo , Proteínas do Leite/química , Nematoides/metabolismo , Nematoides/microbiologia , Nitrogênio/química , Rabditídios/metabolismo , Rabditídios/microbiologia , Simbiose , Proteínas do Soro do Leite , Xenorhabdus/isolamento & purificação , Xenorhabdus/metabolismoRESUMO
The production of infective juvenile stages (IJ) of the entomopathogenic nematode Steinernema carpocapsae in the presence of its symbiotic bacterium Xenorhabdus nematophilus was carried out in orbitally agitated bottles. Four complex culture media (M1-M4) were used, containing from 8% to 28% (by vol.) agave juice (aguamiel) from Mexican maguey-pulquero (Agave spp) as the main carbohydrate source. After 20 days of fermentation, a maximum viable IJ concentration of 249,000 IJ/ml and an initial nematode population multiplication factor of x620 were achieved when medium M4 was used (aguamiel concentration in this medium was 28% by vol.). M4 medium contained (w/v): 0.3% total nitrogen, 3.2% total carbohydrates and 3.0% total fat. According to the results obtained, total carbohydrates concentration appeared to be of great importance in obtaining high IJ concentrations.