RESUMO
Dolphin morbillivirus (DMV) was isolated in striped dolphins Stenella coeruleoalba from the Mediterranean Sea stranded along the coast of Spain during a lethal epidemic that killed thousands of individuals in 1990-1992. Though some of these isolates (MUC, 16A and the reference strain) have been extensively characterised, details on their origin were not reported in the literature, and records for these isolates are often difficult to trace and are, sometimes, erroneous. Here, we provide unpublished biological and histopathological data for these isolates, summarize the literature on their characterization and make suggestions for future studies.
Assuntos
Morbillivirus , Stenella , Animais , Mar Mediterrâneo , EspanhaRESUMO
Crassicauda spp. (Nematoda) infest the cranial sinuses of several odontocetes, causing diagnostic trabecular osteolytic lesions. We examined skulls of 77 Indian Ocean humpback dolphins Sousa plumbea and 69 Indo-Pacific bottlenose dolphins Tursiops aduncus, caught in bather-protecting nets off KwaZulu-Natal (KZN) from 1970-2017, and skulls of 6 S. plumbea stranded along the southern Cape coast in South Africa from 1963-2002. Prevalence of cranial crassicaudiasis was evaluated according to sex and cranial maturity. Overall, prevalence in S. plumbea and T. aduncus taken off KZN was 13 and 31.9%, respectively. Parasitosis variably affected 1 or more cranial bones (frontal, pterygoid, maxillary and sphenoid). No significant difference was found by gender for either species, allowing sexes to be pooled. However, there was a significant difference in lesion prevalence by age, with immature T. aduncus 4.6 times more likely affected than adults, while for S. plumbea, the difference was 6.5-fold. As severe osteolytic lesions are unlikely to heal without trace, we propose that infection is more likely to have a fatal outcome for immature dolphins, possibly because of incomplete bone development, lower immune competence in clearing parasites or an over-exuberant inflammatory response in concert with parasitic enzymatic erosion. Cranial osteolysis was not observed in mature males (18 S. plumbea, 21 T. aduncus), suggesting potential cohort-linked immune-mediated resistance to infestation. Crassicauda spp. may play a role in the natural mortality of S. plumbea and T. aduncus, but the pathogenesis and population level impact remain unknown.
Assuntos
Crânio , Animais , Golfinhos , Oceano Índico , Masculino , África do SulRESUMO
Trophically-transmitted parasites are regularly exposed to potential new hosts through food web interactions. Successful colonization, or switching, to novel hosts, occur readily when 'donor' and 'target' hosts are phylogenetically related, whereas switching between distantly related hosts is rare and may result from stochastic factors (i.e. rare favourable mutations). This study investigates a host-switching event between a marine acanthocephalan specific to pinnipeds that is apparently able to reproduce in Magellanic penguins Spheniscus magellanicus from Brazil. Detailed analysis of morphological and morphometrical data from acanthocephalans from penguins indicates that they belong to Corynosoma australe Johnston, 1937. Partial fragments of the 28S rRNA and mitochondrial cox1 genes were amplified from isolates from penguins and two pinniped species (i.e. South American sea lion Otaria flavescens and South American fur seal Arctocephalus australis) to confirm this identification. Infection parameters clearly differ between penguins and the two pinniped species, which were significantly lower in S. magellanicus. The sex ratio of C. australe also differed between penguins and pinnipeds; in S. magellanicus was strongly biased against males, while in pinnipeds it was close to 1:1. Females of C. australe from O. flavescens were smaller than those from S. magellanicus and A. australis. However, fecundity (i.e. the proportion of fully developed eggs) was lower and more variable in females collected from S. magellanicus. At first glance, the occurrence of reproductive individuals of C. australe in Magellanic penguins could be interpreted as an adaptive colonization of a novel avian host through favourable mutations. However, it could also be considered, perhaps more likely, as an example of ecological fitting through the use of a plesimorphic (host) resource, since the ancestors of Corynosoma infected aquatic birds.
Assuntos
Acantocéfalos , Otárias/parasitologia , Interações Hospedeiro-Parasita/fisiologia , Leões-Marinhos/parasitologia , Spheniscidae/parasitologia , Animais , Ecologia , Feminino , Masculino , Filogenia , Razão de MasculinidadeRESUMO
The genus Neogrubea Dillon & Hargis, 1968 (syn. Asymmetria Suriano, 1975) is revised based on examination of type- and voucher material, and from new specimens collected from the gills of Seriolella porosa Guichenot and Stromateus brasiliensis Fowler from off Patagonia, Argentina. Morphological comparisons based on light and scanning electron microscopy and molecular data (partial SSU and LSU rDNA sequences) of the monogeneans from off Patagonia suggest that N. seriolellae Dillon & Hargis, 1968 (syns N. stromateae Gibson, 1976, A. asymmetria Suriano, 1975 and A. platensis Rey & Meneses, 1985) is currently the only species of the genus. Neogrubea soni Evdokimova, 1969 is considered a species inquirenda. An emended diagnosis of Neogrubea is presented, and new host and locality records for N. seriolellae are given in detail. Morphological characters of the members of the mazocraeid subfamily Grubeinae Price, 1961 are also discussed.
Assuntos
Trematódeos , Animais , Argentina , DNA Ribossômico/genética , Brânquias/parasitologia , Microscopia Eletrônica de Varredura , Perciformes/parasitologia , Especificidade da Espécie , Trematódeos/anatomia & histologia , Trematódeos/classificação , Trematódeos/genéticaRESUMO
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 describe a new heterophyid species, Ascocotyle (Ascocotyle) patagoniensis n. sp., based on specimens collected from the intestines of the South American sea lion Otaria flavescens from Patagonia (Argentina). Ascocotyle (A.) patagoniensis n. sp. is distinguished from the other species of the subgenus by the number of circumoral spines, which are arranged in 2 rows of 18 to 23. The new species also differs from the other species in having a gonotyl without papillae. The specimens exhibited the widest seminal receptacle described for a species of this subgenus. Species of the subgenus Ascocotyle usually infect fish-eating birds or mammals in freshwater or brackish habitats. Ascocotyle (A.) patagoniensis n. sp. is the first species of the subgenus described from a marine mammal. However, no metacercariae of Ascocotyle spp. were found in 542 marine teleosts from 20 species collected in the same locality. The life cycle of the marine species from the Ascocotyle -complex infecting pinnipeds remains elusive.
Assuntos
Heterophyidae/classificação , Enteropatias Parasitárias/veterinária , Leões-Marinhos/parasitologia , Infecções por Trematódeos/veterinária , Animais , Argentina , Oceano Atlântico , Feminino , Heterophyidae/anatomia & histologia , Heterophyidae/isolamento & purificação , Enteropatias Parasitárias/parasitologia , Intestinos/parasitologia , Masculino , Infecções por Trematódeos/parasitologiaRESUMO
We reviewed prominent emerging infectious diseases of cetaceans, examined their potential to impact populations, re-assessed zoonotic risk and evaluated the role of environmental stressors. Cetacean morbilliviruses and papillomaviruses as well as Brucella spp. and Toxoplasma gondii are thought to interfere with population abundance by inducing high mortalities, lowering reproductive success or by synergistically increasing the virulence of other diseases. Severe cases of lobomycosis and lobomycosis-like disease (LLD) may contribute to the death of some dolphins. The zoonotic hazard of marine mammal brucellosis and toxoplasmosis may have been underestimated, attributable to frequent misdiagnoses and underreporting, particularly in developing countries and remote areas where carcass handling without protective gear and human consumption of fresh cetacean products are commonplace. Environmental factors seem to play a role in the emergence and pathogenicity of morbillivirus epidemics, lobomycosis/LLD, toxoplasmosis, poxvirus-associated tattoo skin disease and, in harbour porpoises, infectious diseases of multifactorial aetiology. Inshore and estuarine cetaceans incur higher risks than pelagic cetaceans due to habitats often severely altered by anthropogenic factors such as chemical and biological contamination, direct and indirect fisheries interactions, traumatic injuries from vessel collisions and climate change.
Assuntos
Cetáceos/fisiologia , Doenças Transmissíveis Emergentes/epidemiologia , Meio Ambiente , Estresse Fisiológico , Toxoplasmose Animal/epidemiologia , Animais , Brucelose/epidemiologia , Brucelose/microbiologia , Humanos , Micoses/epidemiologia , Micoses/microbiologia , Toxoplasmose Animal/parasitologia , Viroses/epidemiologia , Viroses/virologia , Zoonoses/epidemiologiaRESUMO
The presence of tattoo skin disease (TSD) was examined in 1392 free-ranging and dead odontocetes comprising 17 species from the Americas, Europe, South Africa, New Zealand and Greenland. We investigated whether TSD prevalence varied with sex, age and health status. TSD was encountered in cetaceans from the Pacific and Atlantic Oceans as well as in those from the North, Mediterranean and Tasman Seas. No clear patterns related to geography and host phylogeny were detected, except that prevalence of TSD in juveniles and, in 2 species (dusky dolphin Lagenorhynchus obscurus and Burmeister's porpoise Phocoena spinipinnis), in adults was remarkably high in samples from Peru. Environmental factors and virus properties may be responsible for this finding. Sex did not significantly influence TSD prevalence except in the case of Peruvian P. spinipinnis. Generally, there was a pattern of TSD increase in juveniles compared to calves, attributed to the loss of maternal immunity. Also, in most samples, juveniles seemed to have a higher probability of suffering TSD than adults, presumably because more adults had acquired active immunity following infection. This holo-endemic pattern was inverted in poor health short-beaked common dolphins Delphinus delphis and harbour porpoises Phocoena phocoena from the British Isles, and in Chilean dolphins Cephalorhynchus eutropia from Patagonia, where adults showed a higher TSD prevalence than juveniles. Very large tattoos were seen in some adult odontocetes from the SE Pacific, NE Atlantic and Portugal's Sado Estuary, which suggest impaired immune response. The epidemiological pattern of TSD may be an indicator of cetacean population health.
Assuntos
Cetáceos/fisiologia , Infecções por Poxviridae/epidemiologia , Dermatopatias/epidemiologia , Distribuição por Idade , Doenças dos Animais/epidemiologia , Doenças dos Animais/virologia , Animais , Chordopoxvirinae/fisiologia , Feminino , Masculino , Fatores Sexuais , Dermatopatias/virologiaRESUMO
Antarctophthirus microchir was originally described from Phocarctos hookeri on the basis of 1 female and 1 male only. We redescribe adults and describe, for the first time, the 3 nymphal stages from specimens collected from Otaria flavescens from Patagonia, using light and scanning electron microscopy. The present material can be distinguished from other Antarctophthirus species by the presence of a fringe of setae on the back of the head, only present in Antarctophthirus trichechi and Antarctophthirus callorhini. However, A. trichechi also possess a prominent proboscis with large hooks, and A. callorhini presents less abundant and nonuniform abdominal scales in shape and size. Other differential features of A. microchir are the pattern of ovoid and uniform scales and longitudinal grooves in the surface of spines. Nymphal stage 1 differs from 2 and 3 mainly by the absence of scales and thorax without ventral spines or hairs. Nymphal stages 2 and 3 may be distinguished by the disposition of the occipital apophyses. Antarctophthirus microchir has been reported from 5 sea lion species from both hemispheres. Considering the conservative morphology, and ecological and evolutionary features of sucking lice, we raise the question of whether A. microchir from different sea lion hosts may represent a complex of cryptic species.