RESUMO
Species of South American subterranean rodents belonging to the genus Ctenomys (commonly called tuco-tucos) are widely distributed across the southern Neotropical region. Despite their relatively well-studied biology and reproductive physiology, current knowledge of their ectoparasite fauna is limited to a few ambiguous studies, based on scattered samples from a small number of host individuals. Ctenomys talarum is the most widely distributed species in the genus. Lice (Phthiraptera) were collected from these tuco-tucos throughout their entire coastal range. Two species, one chewing louse (Gyropus parvus), and one sucking louse (Eulinognathus americanus) were collected. The distribution ranges for both louse species were extended with new locality records. No lice were found in two host populations. Furthermore, co-occurrence of both ectoparasites was not detected.
Assuntos
Interações Hospedeiro-Parasita , Infestações por Piolhos/veterinária , Ftirápteros/crescimento & desenvolvimento , Roedores/parasitologia , Animais , Infestações por Piolhos/parasitologia , Filogeografia , América do Sul , Topografia MédicaRESUMO
Various factors can affect the parasite distribution on a host. In this study, the influence of sex, body size, and locality of a rodent host, Oligoryzomys nigripes, on lice abundance was investigated. A generalized linear model indicated that the sex and locality of O. nigripes significantly contributed to the variation in lice abundance on the host. The male bias of lice parasitizing the rodent host O. nigripes may be associated with intersexual differences in physiology and behavior, while locality differences in lice abundance may be associated with differences in host density and diversity between the two localities sampled. Studies of host-parasite associations improve the understanding of the ecology of infectious diseases, as well as the evolution of these host-parasite interactions.
Assuntos
Ectoparasitoses/veterinária , Carga Parasitária , Ftirápteros/crescimento & desenvolvimento , Doenças dos Roedores/epidemiologia , Doenças dos Roedores/parasitologia , Sigmodontinae/parasitologia , Animais , Brasil/epidemiologia , Ectoparasitoses/epidemiologia , Ectoparasitoses/parasitologia , Feminino , Geografia , Masculino , Fatores SexuaisRESUMO
The members of the Family Echinophthiriidae (Phthiraptera: Anoplura) are unique among insects because they infest hosts with an amphibious lifestyle. During their evolution they developed morphological traits that are reflected in unique features. The SEM is a helpful tool to analyze them. Knowing in detail the external structure of these lice is the first step to understand the whole process that derived from the co-adaptation of lice and pinnipeds to the marine environment. For the first time, we studied the external structure of all stages of an echinophthiriid louse. The results are discussed in the light of their evolutionary, functional, and ecological implications.
Assuntos
Adaptação Fisiológica , Evolução Biológica , Infestações por Piolhos/veterinária , Ftirápteros/ultraestrutura , Leões-Marinhos/parasitologia , Animais , Infestações por Piolhos/parasitologia , Estágios do Ciclo de Vida , Microscopia Eletrônica de Varredura/métodos , Ftirápteros/crescimento & desenvolvimentoRESUMO
We analysed population dynamics of the louse Antarctophthirus microchir in pups of the South American sea lion, Otaria flavescens, at the Punta León rookery (Argentina) over a period of 2 years. A total of 136 pups were aged and marked at the beginning of the lactation period ashore, then sampled for lice at different times within 30 days. Sampling was restricted to the chest and belly, two sites where lice were especially abundant. This concentration on ventral areas might protect lice from thermal stress in the austral summer. Infestation patterns in pups 3 days old suggested that the potential for transmission increased from first nymphs to adults. Population trends of each instar with pup age, based on standardised values of abundance, were conserved between years, reflecting the basic dynamics of recruitment and reproduction. However, trends based on log-transformed abundances varied significantly between years; apparently, environmental conditions affected growth of lice populations differently each year. Stage-based deterministic models for population growth of A. microchir suggested generation times from 18 to 23 days. Accordingly, only 2 lice generations might be produced before pups start going to the sea. Shortening the cycle to accommodate a third generation might be risky, whereas a 2-generation cycle might at least result in larger females producing higher numbers of viable offspring.
Assuntos
Animais Recém-Nascidos/parasitologia , Infestações por Piolhos/veterinária , Estágios do Ciclo de Vida , Ftirápteros/crescimento & desenvolvimento , Leões-Marinhos/parasitologia , Animais , Argentina , Feminino , Infestações por Piolhos/epidemiologia , Infestações por Piolhos/parasitologia , Masculino , Ftirápteros/classificação , Dinâmica Populacional , Prevalência , Reprodução/fisiologia , Leões-Marinhos/crescimento & desenvolvimento , Leões-Marinhos/fisiologiaRESUMO
Parasite life-history characteristics, the environment, and host defenses determine variation in parasite population parameters across space and time. Parasite abundance and distribution have received little attention despite their pervasive effects on host populations and community dynamics. We used analyses of variance to estimate the variability of intensity, prevalence, and abundance of 4 species of lice (Insecta: Phthiraptera) infecting Galápagos doves and Galápagos hawks and 1 haemosporidian parasite (Haemosporida: Haemoproteidae) infecting the doves across island populations throughout their entire geographic ranges. Population parameters of parasites with direct life cycles varied less within than among parasite species, and intensity and abundance did not differ significantly across islands. Prevalence explained a proportion of the variance (34%), similar to infection intensity (33%) and parasite abundance (37%). We detected a strong parasite species-by-island interaction, suggesting that parasite population dynamics is independent among islands. Prevalence (up to 100%) and infection intensity (parasitemias up to 12.7%) of Haemoproteus sp. parasites varied little across island populations.
Assuntos
Doenças das Aves/epidemiologia , Columbidae/parasitologia , Haemosporida , Falcões/parasitologia , Infestações por Piolhos/veterinária , Infecções Protozoárias em Animais/epidemiologia , Animais , Doenças das Aves/parasitologia , Equador/epidemiologia , Haemosporida/crescimento & desenvolvimento , Infestações por Piolhos/epidemiologia , Infestações por Piolhos/parasitologia , Ftirápteros/crescimento & desenvolvimento , Prevalência , Infecções Protozoárias em Animais/parasitologiaRESUMO
Os efeitos da temperatura, umidade relativa e precipitação pluvial na população de Bovicola caprae parasitando caprinos na região semi-árida do Estado da Paraíba foram avaliados de agosto 1999 a julho de 2002. Nos dois primeiros anos (agosto de 1999 a julho de 2001) 30 caprinos foram examinados, enquanto que 16 caprinos foram examinados no terceiro ano (agosto de 2001 a julho de 2002). Os animais eram mestiços adultos de ambos os sexos e foram abatidos para consumo humano no Matadouro Público de Patos, PB. As amostras de piolhos foram coletadas de três regiões anatômicas do corpo: maxilar, dorso e glúteo. O teste de Spearman (p< 0.05) foi utilizado na tentativa de se estabelecer uma correlação entre a intensidade média de infestação de todos os estágios e o número total de cada estágio com os fatores abióticos. A prevalência variou entre 75 e 100% durante o período de estudo. O aumento da população de piolhos nos períodos de seca deveu-se provavelmente a nutrição deficiente dos animais em conseqüência da escassez de pastagem e manejo inadequado do rebanho em vez dos efeitos dos fatores abióticos.(AU)
The effects of temperature, humidity and rainfall on field population trend of the biting louse Bovicola caprae, parasitizing goats bred in the semiarid region of the State of Paraiba, northeastern Brazil were monthly evaluated from August 1999 to July 2002. In the first two years (August 1999 to July 2001) 30 goats were examined, whereas 16 goats were examined in the last year (August 2001 to July 2002). All goats were crossbred, both sexes and abated for human consumption. The lice were collected in an area 4cm of diameter at three body sites: maxillary, back line and haunch. Spearman correlation analysis was conducted (p< 0.05) between monthly average intensity of infestation of all stages (egg, larva, nymph, male and female) of the life cycle pooled and monthly total counts of each stage and mean temperature, mean relative humidity and rainfall. B. caprae was found throughout the year with prevalence of 75-100%. Increase of the louse population during the drier months was probably a consequence of poor nutrition due to reduced pasture and inadequate husbandry practices instead the influence of abiotic factors.(AU)
Assuntos
Animais , Ftirápteros/crescimento & desenvolvimento , Temperatura , Precipitação Atmosférica , Prevalência , CabrasRESUMO
Theory predicts a positive relationship between parasite infection intensity and host density. However, this generalization is complicated in natural systems by differences in life history among parasite taxa, e.g., transmissibility. Accordingly, predictions relating host density to parasite load should be specific to each parasite taxon. To illustrate this, we studied parasites that differed greatly in life history in the context of the Galapagos hawk's (Buteo galapagoensis) variably cooperative mating system. Two louse (Phthiraptera) species were collected: Colpocephalum turbinatum (Amblycera), with 53 host species, and Degeeriella regalis (Ischnocera), with 10 host species, although B. galapagoensis was the only known Galapagos host. Sixty territorial adult male hawks from 26 groups of 1-6 males were quantitatively sampled for lice. Average abundance and intensity of C. turbinatum but not D. regalis were significantly larger in large groups of hawks than small groups. Males from the same polyandrous group harbored significantly correlated abundances of C. turbinatum but not D. regalis. Prevalence, average abundance, and intensity of C. turbinatum were significantly higher than D. regalis. These are the first results to demonstrate significant differences in a suite of population responses between these louse suborders in the context of host sociality.
Assuntos
Comportamento Animal , Doenças das Aves/parasitologia , Falcões/parasitologia , Infestações por Piolhos/veterinária , Comportamento Social , Animais , Doenças das Aves/epidemiologia , Doenças das Aves/transmissão , Equador/epidemiologia , Infestações por Piolhos/epidemiologia , Infestações por Piolhos/parasitologia , Infestações por Piolhos/transmissão , Masculino , Ftirápteros/classificação , Ftirápteros/crescimento & desenvolvimento , PrevalênciaRESUMO
Several arthropods that live as ectoparasites on domestic dogs can cause severe dermatitis or act as vectors of pathogenic agents, resulting in serious diseases not only in dogs, but also in humans. We studied ectoparasites found on Canis familiaris sampled in five areas in Buenos Aires province, Argentina. The prevalence of fleas, ticks and lice was analyzed, as well as their seasonal variations through the different sites studied. The kind of infestation found in each host was determined and the intensity of natural infestation was estimated. The study was carried out from October 2001 to July 2002, with 116 dogs that lived in rural areas and did not receive control treatments. In order to remove the ectoparasites, the dogs' skin was rubbed with a piece of cotton soaked in ether. All dogs had at least one species of ectoparasites. A total number of 5193 ectoparasites were found corresponding to four species, 15.7% Ctenocephalides canis, 73% Rhipicephalus sanguineus, 1.8 Linognathus setosus and 9.4% Heterodoxus spiniger. R. sanguineus was the most abundant species, and C. canis was the only flea species found. This may be due to the dogs being exclusively rural animals. Within the zones sampled, Magdalena showed the greatest prevalence, maybe as a consequence of having the highest relative humidity in relation to the other areas. Triple infestation (ticks-fleas-lice) was observed in 56.9% of the dogs; 39.6% presented double infestation, most being ticks-fleas, and only 3.4% showed simple infestation (lice). Female hosts were the most affected. Even though there were records of ectoparasites throughout all the year, a higher intensity was observed during the spring months, most likely as a result of the increase in temperature after the winter months.
Assuntos
Doenças do Cão/parasitologia , Cães/parasitologia , Ectoparasitoses/veterinária , Ftirápteros/crescimento & desenvolvimento , Sifonápteros/crescimento & desenvolvimento , Carrapatos/crescimento & desenvolvimento , Animais , Argentina/epidemiologia , Doenças do Cão/epidemiologia , Ectoparasitoses/epidemiologia , Ectoparasitoses/parasitologia , Feminino , Masculino , Prevalência , População Rural , Estações do AnoAssuntos
Humanos , Masculino , Feminino , Pré-Escolar , Adolescente , Infestações por Piolhos/etiologia , Escabiose/etiologia , Saneamento de Residências , Infestações por Piolhos/tratamento farmacológico , Infestações por Piolhos/prevenção & controle , Infestações por Piolhos/transmissão , Hexaclorocicloexano/uso terapêutico , Ftirápteros/efeitos dos fármacos , Ftirápteros/crescimento & desenvolvimento , Ftirápteros/patogenicidade , Piretrinas/uso terapêutico , Interações Hospedeiro-Parasita , Sarcoptes scabiei/efeitos dos fármacos , Sarcoptes scabiei/patogenicidade , Escabiose/diagnóstico , Escabiose/tratamento farmacológico , Escabiose/transmissãoRESUMO
Este trabajo es un aporte para el conocimiento de la morfofisiología de Pediculus capitis, agente causal de la pediculosis, con imágenes a microscopía electrónica (AU)
Assuntos
Ftirápteros/anatomia & histologia , Ftirápteros/crescimento & desenvolvimento , Ftirápteros/ultraestrutura , Infestações por Piolhos/etiologiaRESUMO
Este trabajo es un aporte para el conocimiento de la morfofisiología de Pediculus capitis, agente causal de la pediculosis, con imágenes a microscopía electrónica
Assuntos
Ftirápteros/anatomia & histologia , Infestações por Piolhos/etiologia , Ftirápteros/crescimento & desenvolvimento , Ftirápteros/ultraestruturaRESUMO
Forty-eight migrant greater yellowlegs, Tringa melanoleuca, collected from southwestern Texas and southeastern New Mexico were examined for metazoan parasites. Nine helminth and 7 ectoparasite species were collected. Five new host records were recorded. The helminth fauna showed little diversity, little concentration for dominance, and no significant positive or negative associations between species were found. All species of helminths showed a contagious distribution. The component helminth community consisted of 2 core, 3 secondary, and 4 satellite species, and there was no host specialist. A checklist of metazoan parasites reported from greater yellowlegs in North America is included.