Distribution patterns of marine bird digenean larvae in periwinkles along the southern coast of the Barents Sea.
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An important component of the parasite fauna of seabirds in arctic regions are the flukes (Digena). Different species of digeneans have life cycles which may consist of 1 intermediate host and no free-living larval stages, 2 intermediate hosts and 1 free-living stage, or 2 intermediate hosts and 2 free-living larval stages. This study examined the distribution of such parasites in the intertidal zones of the southern coast of the Barents Sea (northwestern Russia and northern Norway) by investigating 2 species of periwinkles (Littorina saxatilis and L. obtusata) which are intermediate hosts of many species of digeneans. A total of 26,020 snails from 134 sampling stations were collected. The study area was divided into 5 regions, and the number of species, frequency of occurrence and prevalence of different digenean species and groups of species (depending on life cycle complexity) were compared among these regions, statistically controlling for environmental exposure. We found 14 species of digeneans, of which 13 have marine birds as final hosts. The number of species per sampling station increased westwards, and was higher on the Norwegian coast than on the Russian coast. The frequency of occurrence of digeneans with more than 1 intermediate host increased westwards, making up a larger proportion of the digeneans among infected snails. This was significant in L. saxatilis. The prevalence of different species showed the same pattern, and significantly more snails of both species were infected with digeneans with complicated life cycles in the western regions. In L. saxatilis, environmental exposure had a statistically significant effect on the distribution of the most common digenean species. This was less obvious in L. obtusata. The causes of changing species composition between regions are probably (1) the harsh climate in the eastern part of the study area reducing the probability of successful transmission of digeneans with complicated life cycles, and (2) the distribution of different final hosts. (+info)
First record of Emetha audouini, a cymothoid isopod parasite, from cultured sea bass Dicentrarchus labrax in Greece.
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For the first time, Emetha audouini (Milne Edwards, 1840), a cymothoid isopod, is reported parasitising cage cultured sea bass Dicentrarchus labrax L., 1758 in Greece. The specimens observed are larvae (Pulli II). They were found in great numbers in the buccal and branchial cavity of young (3.5 m.o. old) sea bass, in an intensive cage farm facility. This parasite is certainly transferred to sea bass from wild populations of Sparidae or Centracanthidae. Serious lesions were visible and typical of a crustacean infection, with extensive and deep skin damage in the head area. The cumulative mortality, over a 2 wk period, was 10.75%. The parasitic problem was successfully dealt with by optimization of management practices rather than use of costly and dangerous chemotherapeutants. (+info)
A survey of some parasites and diseases of several species of bivalve mollusc in northern Western Australia.
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Pteriid oysters (Pinctada maxima, Pinctada margaritifera, Pinctada albina, Pteria penguin), rock oysters (Saccostrea glomerata, Saccostrea cuccullata, Saccostrea echinata) and representatives of other taxa (Malleidae, Isognomonidae, Pinnidae, Mytilidae, Spondylidae, Arcidae) from the wild, and 4670 hatchery-reared P. maxima, from northern and Western Australia, were examined for parasites and diseases. Rickettsiales-like inclusions and metacestodes of Tylocephalum occurred in most species. Intranuclear virus-like inclusions occurred in 1/415 wild P. maxima, 1/1254 S. cuccullata, 3/58 Isognomon isognomum, 1/80 Pinna bicolor and 1/45 Pinna deltodes. Perkinsus was histologically observed in 1/4670 P. maxima spat, 2/469 P. albina, 1/933 S. glomerata, 16/20 Malleus meridianus, 12/58 I. isognomum, 1/45 P. deltodes, 5/12 Spondylus sp., 1/16 Septifer bilocularis and 3/6 Barbatia helblingii. One of 1254 S. cuccullata was heavily systematically infected with Perkinsus merozoites, meronts and schizonts, and was patently diseased. Other potentially serious pathogens included Haplosporidium sp. in 6/4670 P. maxima spat, Marteilia sydneyi from 1/933 S. glomerata, and Marteilia sp. (probably M. lengehi) (1/1254) and Haplosporidium sp. (125/1254) from S. cuccullata. The latter were associated with epizootics on offshore islands, with heaviest prevalence (45%) in oysters with empty gonad follicles. Marteilioides sp. infected the oocytes of 9/10 female S. echinata from Darwin Harbour. Details of geographical distribution and pathology are given, and the health of the bivalves examined is discussed. (+info)
Conservation of sequence in the internal transcribed spacers and 5.8S ribosomal RNA among geographically separated isolates of parasitic scuticociliates (Ciliophora, Orchitophryidae).
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Nucleotide sequence from the internal transcribed spacers (ITS1 and ITS2) and the 5.8S gene from the ribosomal RNA gene cluster of isolates of the scuticociliate Orchitophrya stellarum from 4 asteroid hosts were compared. Surprisingly, these data (495 bp) were identical for O. stellarum isolated from the testes of Asterias amurensis from Japan; Pisaster ochraceus from British Columbia, Canada; Asterias rubens from The Netherlands; and Asterias vulgaris from Prince Edward Island, Canada. These sequence data were compared to those from 3 scuticociliates which parasitise crustaceans: Mesanophrys pugettensis, M. chesapeakensis and Anophryoides haemophila. No difference was found in this region between the nucleotide sequence of M. pugettensis and M. chesapeakensis. The sequence of Mesanophrys spp. differed by 9.2% in the ITS1 and 4.7% in the ITS2 from that of O. stellarum. The sequence from the ITS1 (135 bp) and ITS2 (233 bp) of A. haemophila differed by 42.6 and 20.5% respectively from those of O. stellarum. Therefore, nucleotide sequence of the ITS regions in these scuticociliates is highly conserved. (+info)
Lassa virus infection in Mastomys natalensis in Sierra Leone. Gross and microscopic findings in infected and uninfected animals.
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Pathological examinations of 28 wild-caught Mastomys natalensis from Sierra Leone, 14 of which were positive for Lassa virus by tissue culture, are reported. The high frequency of neoplastic and degenerative diseases observed among older animals in closed colonies of M. natalensis were not observed in the wild animals studied. This is probably a reflection of the age distribution of the study population, since the life expectancy of wild Mastomys is less than a year. Inflammatory lesions were nonetheless identified, some of which were similar to those described in laboratory colonies. Frequent lesions were myocarditis (54%), myositis (32%), interstitial pneumonitis (50%), intercapillary glomerulosclerosis (36%), and acute nephrosis (14%). Follicular and nodular lymphoid hyperplasia were evident in the spleen (74%) and Peyer's patches (64%). Lymphoid cell accumulations were prominent in the salivary glands (36%), periportal hepatic region (25%), lungs (32%), perivascular regions (36%), and kidney (21%). Cytomegalic inclusion body sialoadenitis was common (25%). Coccidiosis was evident in the intestinal tract (25%), kidney (25%), and muscle (21%). One neoplasm, a parahepatic haemangioma, was observed histologically.Mean body weights and lengths for virus-positive animals (33 g and 9.2 cm) and virus-negative animals (54 g and 12.2 cm) showed that virus-positive animals were smaller in weight and shorter in length. Since the age of the animals could not be determined, these differences remain unexplained.In comparison with virus-negative animals, virus-positive Mastomys had higher frequencies of splenic follicular hyperplasia (82% against 50%), myocarditis (79% against 29%), perivascular lymphoid cell accumulation (57% against 7%), myositis (50% against 14%), and cytomegalic inclusion body sialoadenitis (36% against 14%). The frequency of lymphoid hyperplasia of Peyer's patches was high in both groups of animals (71% and 57%).The presence of Lassa virus, small size, myocarditis, and lymphoid perivasculitis appeared to be interrelated, but larger and better controlled studies are required to elucidate the relationship. (+info)
Mammalian metabolism, longevity and parasite species richness.
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Basal metabolic rate (BMR) scales allometrically with body mass in mammals, but the reasons why some species have higher or lower metabolic rates than predicted from their body mass remain unclear. We tested the idea that parasite species richness may be a contributory factor by performing a comparative analysis on 23 species of mammals for which data were available on parasite species richness, BMR, body mass and two potentially confounding variables, i.e. host density and host longevity. Parasite species richness was positively correlated with BMR and negatively correlated with host longevity independent of body mass. (+info)
Cebus apella (Primata: Cebidae) as a new host for Fonsecalges johnjadini (Acari: Psoroptidae, Cebalginae) with a description of anatomopathological aspects.
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Mites collected from the auditory canal of Cebus apella (capuchin monkey), family Cebidae, were identified as Fonsecalges johnjadini (Psoroptidae, Cebalginae). It is the first record of this parasite from this monkey. This paper emphasizes the importance of clinical and anatomopathological examinations for parasitic diagnosis in wild animals. (+info)
Long-term monitoring on the occurrence of a myxosporean parasite Kudoa camarguensis (Myxosporean) on the common goby (Teleostei, pisces) Pomatoschistus microps.
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The evolution of a host-parasite system composed of Pomatoschistus microps-Kudoa camarguensis was investigated in the Vaccares lagoon (Rhjne river Delta, France) from 1993 to 1997. During this long-term monitoring, centennial flooding of the Rhjne river occurred, leading to an inrush of about 110 million m3 of freshwater in the Vaccares lagoon. The salinity drastically dropped from 14 to 5 g l(-1) in 1 wk. We observed that the annual prevalence and abundance of the myxosporean parasite decreased from 12.18 in 1993 to 3.7% in 1997 and from 1.10 in 1993 to 0.27 in 1997, respectively. Here, we discuss the possible reasons for the rapid decline of this host-parasite system following the flood. (+info)