Microfilaraemia associated with Pelecitus roemeri in a western grey kangaroo (Macropus fuliginosus).
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Animals↗
Biomedical subjects
D M Spratt
Publications and source records attributed to D M Spratt.
Rileyella petauri gen. nov., sp. nov. (Pentastomida: Cephalobaenida) from the lungs and nasal sinus of Petaurus breviceps (Marsupialia: Petauridae) in Australia.
A new cephalobaenid pentastome, Rileyella petauri gen: nov., sp. nov. from the lungs and nasal sinus of the petaurid marsupial, Petaurus breviceps, is described. It is the smallest adult pentastome known to date, represents the first record of a mammal as the definitive host of a cephalobaenid and may represent the only pentastome known to inhabit the lungs of a mammal through all its instars, with the exception of patent females. Adult males, non-gravid females and nymphs moulting to adults occur in the lungs; gravid females occur in the nasal sinus. R. petauri is minute and possesses morphological features primarily of the Cephalobaenida but the glands in the cephalothorax and the morphology of the copulatory spicules are similar to some members of the remaining pentastomid order, the Porocephalida. This unusual combination of features distinguish the new genus from other genera in the Cephalobaenida. The occurrence of only seven fully-formed larvae in eggs in the uterus, each representing about 10% of the length of the patent female, and her presence in the nasal sinus of a dependent juvenile P. breviceps (36 gm) implies a direct life cycle.
Animals↗
Aspects of the life history of Muspicea borreli (Nematoda: Muspiceidae), parasite of the house mouse (Mus domesticus) in Australia.
Prevalence of Muspicea borreli (Nematoda) infection in wild populations of Mus domesticus in forests in southeastern New South Wales and in rural Canberra, Australia was variable, relatively low and the parasite occurred predominantly in male mice. Experimental infection of BALB/c mice occurred only via subcutaneous inoculation but was achieved using i) adults containing embryonating eggs, ii) adults containing active larvae and iii) active larvae dissected from the uterus of female worms. Experimental infection was not established using adults containing unembryonated eggs and was not established via intraperitoneal, percutaneous nor oral routes. Evidence indicates that larvae develop to the infective stage in the uterus of the adult worm, suggests that an obligate developmental phase on the host skin does not occur and that autoinfection is possible. Experimental infection predominated in males; females rarely became infected. When male BALB/c mice were inoculated subcutaneously with M. borrelia, immediately paired with an uninoculated female and permitted to breed for 90 days, infection was found in male and female offspring only of the second and subsequent litters or in the breeding female partner. Transmission to the young occurred within 21 days of birth and fifth-stage M. borrelia were found in offspring of the second and subsequent litters only after 35 or more days. However, when a male was inoculated but mating delayed for 23 days, infection was found in progeny of the first and second litters. The life cycle is direct and the prepatent period in BALB/c mice is estimated at 50-60 days. The precise mode of transmission of the parasite in breeding pairs of mice was not determined but larvae remained active for approximately an hour in balanced saline solutions (pH = 7.2) and in human saliva but died under conditions emulating free-living (tap water pH = 7.1) and stomach (pepsin solution pH = 2) environments. Transmission was not effected by transplacental, transmammary nor transseminal routes. Consequently, it is difficult not to conclude that transmission may occur via penetration of skin or mucous membranes, and allogrooming behaviour may be particularly important in this regard.
Animals↗
Gallegostrongylus australis n. sp. (Nematoda: Angiostrongylidae) from Muridae in Australia, with zoogeographical considerations.
Gallegostrongylus australis n. sp. (Nematoda: Angiostrongylidae) is described from subpleural nodules in the lungs of Rattus fuscipes, R. lutreolus and Mus domesticus in Australia. It is distinguished from G. andersoni occurring in gerbillids in West Africa by the shorter lengths of spicules and gubernaculum, and from G. ibicensis occurring in microtids and murids in Spain by the greater lengths of spicules and gubernaculum and the shorter distances from vulva and from anus to the caudal extremity of females. The parasite has been found only in 16 of 4,227 (prevalence 0.38%) animals representing at least 28 species of native and three species of introduced murid rodents throughout Australia. The genus Gallegostrongylus may be an old one, possibly originating in rats. By rafting and/or human activities the parasite appears to have been distributed around the world where it has encountered suitable intermediate hosts and available niches for colonisation of new definitive hosts. Consequently, morphologically similar but biologically distinct species have evolved in rodent hosts in West Africa, the western Mediterranean, and Australia.
Adaptation, Physiological↗
Life history and pathogenesis of Gallegostrongylus australis (Nematoda: Angiostrongylidae) in muridae.
Gallegostrongylus australis Spratt, Haycock & Walter, 2001 (Nematoda: Angiostrongylidae) developed in Deroceras panormitanum, Lehmannia nyctelia, L. flava and Milax gigates (Gastropoda). The first moult occurred at 18-19 days after infection (DAI) and the second moult at 28 DAI. Larvae were infective to experimental murid definitive hosts at 35 DAI. In experimentally infected Rattus fuscipes larvae moulted L3-4 at 3 DAI and L4-5 at 6-7 DAI. Patency in R.fuscipes, R. lutreolus, R. norvegicus and R. rattus occurred 27-64 DAI and duration varied from 7-392 days. Histopathological changes in the lungs of R. lutreolus and development of debilitating clinical signs, in contrast to R. fuscipes, suggests that the former host-parasite relationship may be the more recent one but other traits suggest the opposite. Patent infections were established in some wild R. rattus and some laboratory R. norvegicus but not in wild M. domesticus, laboratory M. musculus, rabbit, Oryctolagus cuniculus, and marsupial bandicoot, Isoodon macrourus.
Animals↗
Mitochondrial DNA polymorphism within and among species of Capillaria sensu lato from Australian marsupials and rodents.
The nucleotide variation in a mitochondrial DNA (mtDNA) fragment within and among species of Capillaria sensu lato from Australian marsupials and rodents was analyzed using a mutation scanning/sequencing approach. The fragment of the cytochrome c oxidase subunit I (COI) was amplified by PCR from parasite DNA, and analysed by single-strand conformation polymorphism (SSCP) and sequencing. There was no significant variation in SSCP profiles within a morphospecies from a particular host species, but significant variation existed among morphospecies originating from different host species. The same morphospecies was found to occur in 1-3 tissue habitats within one host individual or within different individuals of a particular species of host from the same or different geographical areas, and morphospecies appeared to be relatively host specific at the generic level. The results indicated that the species of Capillaria sensu lato examined, although highly variable in their host and tissue specificity, may exhibit the greatest degree of specificity at the level of host genus.
Animals↗
Neuro-angiostrongyliasis: unresolved issues.
Angiostrongylus cantonensis, the rat lungworm, probably evolved with its hosts, members of the genus Rattus and closely related species, in south-east Asia. Since its first discovery in rats in China and in a case of human infection in Taiwan, the parasite has been found to infect humans and other mammals across a wide and ever-increasing territory, which now encompasses much of south-east Asia, Melanesia, Polynesia and eastern Australia. It has also established a foothold in Africa, India, the Caribbean and south-eastern USA. This dispersal has been a direct result of human activity, and in some cases has been linked with the spread of the African giant land snail, Achatina fulica. However, this snail is not critical to the extension of the parasite's range, as numerous other indigenous molluscan species serve as adequate intermediate hosts; the importance of Achatina to the life cycle may have been over-emphasized. In Australia, the parasite is established along parts of the east coast, and the presence of an indigenous close relative, Angiostrongylus mackerrasae, suggests a long association of the parasite with its local rat hosts, a situation analogous to that of Angiostrongylus malaysiensis in south-east Asia. These three Angiostrongylus species share virtually the same life cycle, but only A. cantonensis has been confirmed to be a human pathogen.
Adult↗
A fatal case of angiostrongyliasis in an 11-month-old infant.
An 11-month-old boy developed flaccid quadriparesis after two months in Fiji, and was transferred to Australia, where a diagnosis of postinfectious myelitis was made. Despite peripheral blood eosinophilia, eosinophils were not detected in the cerebrospinal fluid, and an infective aetiology was not identified. The patient died of progressive bulbar dysfunction. At autopsy, numerous nematodes, identified as Angiostrongylus cantonensis, were seen in vessels of the lungs, brain and spinal cord, associated with pulmonary abscesses and eosinophilic meningitis. A notable feature was the presence of adult nematodes in the lung.
Angiostrongylus cantonensis↗
Haycocknema perplexum n. g., n. sp. (Nematoda: Robertdollfusidae): an intramyofibre parasite in man.
Haycocknema perplexum n. g., n. sp. (Nematoda: Robertdollfusidae) is described from a man in Tasmania, Australia. Adult male and female nematodes and larvae were recovered from myofibres following biopsy of the right vastus lateralis muscle and were associated with a polymyositis. H. perplexum is distinguished from all other genera of the Muspiceoidea by the presence of a large amorphous "cell" supporting a granule-filled, flask- or gourd-shaped reservoir in the rectal region of mature and gravid female nematodes, often containing one or more large, refractile, thick-rimmed "globules" on the external surface of the reservoir, by the small number of ova/eggs/larvae developing in each uterus, by the minute, weakly-sclerotised, almost tubular spicule, by the presence of a pair of ampulla-shaped glands posteriorly and by the presence of lateral bacillary bands comprised of a single row of pore cells spaced irregularly and extending posteriorly to the region of the vulva in immature females.
Adult↗
Polymyositis caused by a new genus of nematode.
We report two patients who presented with increasing malaise and myalgia, and had biopsy-proven polymyositis. Their conditions deteriorated after corticosteroid treatment, and repeat muscle biopsies showed adult and larval nematodes. Anthelminthic treatment was completely successful in both cases. The infecting nematode appears to belong to a new genus and is, to our knowledge, the first known muspiceoid nematode to infect humans. Its life cycle and the route of infection are unknown.
Adult↗
Crocodylocapillaria longiovata n. gen., n. sp. (Nematoda: Capillariidae) from the stomach of crocodiles in Australia and New Guinea.
A new nematode, Crocodylocapillaria longiovata n. gen. and n. sp., is described from the stomach of wild and farmed young crocodiles, Crocodylus johnstoni Krefft, and Crocodylus porosus Schneider, from northern Australia and Papua New Guinea; it is undoubtedly identical with the nematodes previously reported as Capillaria sp. from Crocodylus novaequineae Schmidt from Irian Jaya, Indonesia. This capillariid species represents a new genus, being characterized mainly by the presence of elongate eggs with unusually long protruding polar plugs, a well developed vulvar appendage, a weakly sclerotized spicule, proximal and distal parts of the spicular sheath with spines, and the male posterior end with 2 large lateral caudal lobes and a pair of papillae near the cloacal opening. The body length of C. longiovara males and females is 5,576-7,208 microm and 8,609-14,008 microm, respectively, the spicule is 276-369 microm long; the size of the egg proper is 48-60 x 15-21 microm, length of polar plugs 15-18 microm. Neocapillaria Yi and Guitang, 1994, a junior homonym of Neocapillaria Moravec, 1987, is re-named Sinocapillaria nom. n. and placed as a synonym of Pseudocapillaria Freitas, 1959. Indocapillaria De and Maity, 1995 is retained as a subgenus of Pseudocapillaria because of the possession of a vulvar appendage in the type species. Neocapillaria Moravec, 1987 remains a subgenus of Capillaria Zeder, 1800. A key to genera of the Capillariidae from poikilotherm vertebrates is provided; C. longiovata is the first capillariid species described from the digestive tract of crocodiles.
Alligators and Crocodiles↗
Endoparasite control strategies: implications for biodiversity of native fauna.
Efforts to control the spectrum of diseases that affect humans, our crops and our animals pose problems which need to be debated openly. Widespread use of chemicals in such a broad sphere raises important concerns not only about safety for the users, consumers and target species, but especially about the not so obvious effects upon the ecosystems in which they are used. Some undetermined level of biological diversity is necessary to maintain ecological function and resilience. These, in turn, are necessary for generating the biological resources (trees, fish, wildlife, crops) and ecological services (watershed protection, air cleansing, climate stabilisation, erosion control) on which economic activity and human welfare depend. The driving forces behind decline of biodiversity stem entirely from human activities. Underlying causes are those resulting from the cultural and social factors associated with economic activities and lead to direct depletion of species, and degradation or destruction of habitats. The broad spectrum and high efficacy of the macrocyclic lactones against nematode and arthropod parasites of livestock and companion animals are unprecedented. Cattle, horses, sheep, swine, dogs--to varying degrees all are utilised by humans for economic gain. Detrimental impact upon non-target animals is considered acceptable in eradicating parasites because of their economic importance to commercial livestock production. Production will increase when these parasites are eliminated, but we remain oblivious to the long-term consequences of our actions. What are the ecological limits to rural economic activities? Decomposing animal faeces help to maintain our ecosystem by returning valuable nutrients to the soil. Dung fauna-fungi, yeast, bacteria, nematodes, insects and earthworms--play a non-conspicuous but important and varied role in this decomposition process, a role dependent upon many factors, especially environmental ones. Anthelmintics and pesticides are of considerable value in agriculture, but largely at an unevaluated cost to the greater environment. We have insufficient knowledge of the extent to which a spectrum of anthelmintics and pesticides affect ecological function and ecosystem resilience in our commercial plant and animal production systems. It is time we developed a genuine interest in avoiding "the dialogue of the deal" that in the past has minimised interdisciplinary research between environmental ecology and commercial plant and animal production.
Animals↗
Simondsia paradoxa: newly recorded nematode parasite from feral pigs in Australia.
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Animals↗
The origins and evolutionary expansion of the Strongylida (Nematoda).
The Strongylida are thought to have arisen from free-living rhabditoid nematodes, but the relationships between the major groupings within the Strongylida, the Strongylina, the Metastrongylina, Trichostrongylina and the Ancylostomatina are far from clear in spite of the abundance of morphological data now available for analysis. Evolutionary mechanisms including co-evolution, host switching, host dispersal, use of intermediate hosts, various sites of localisation within the definitive host and modifications of life-cycle strategies appear to have been utilised in the expansion of the Strongylida, with different mechanisms predominating in different families or superfamilies. Co-evolution appears to have been a major mode of evolution in the Strongylina, in contrast to the Trichostrongylina, which have used host dispersal and host-switching to great advantage. The phylogeny of the Ancylostomatina shows little association with host evolution, but does match the feeding preferences of the hosts. The Metastrongylina have utilised intermediate hosts and life cycle modifications including a shift to extra-intestinal sites as major means of diversification, in contrast to the other sub-orders. The review, while indicating much progress in our understanding of the phylogeny of the Strongylida, also reveals that enormous gaps still exist, and emphasises the tentative nature of many of the phylogenetic hypotheses tendered to date.
Animals↗
Apparent lack of genetic variation within Pelecitus roemeri (Nematoda: Filarioidea) from three Australian species of macropodid marsupial.
An electrophoretic study of Pelecitus roemeri from Macropus robustus, M. giganteus and Wallabia bicolor revealed no genetic differences at 23 enzyme loci. The genetic data support the existing morphological evidence that P. roemeri from these three hosts represents a single species. The data show no genetic variation between nematodes from the same or different host species collected in northern and southern Australia. This result is discussed briefly in relation to Price's model of parasite speciation.
Animals↗
Sparganosis in the monotremes Tachyglossus aculeatus and Ornithorhynchus anatinus in Australia.
Sparganosis in the echidna, Tachyglossus aculeatus, is characterized by large subcutaneous masses that may be confused with neoplasms. Plerocercoids, believed to be Spirometra erinacei, were found in the ventral or lateral subcutaneous tissues of three echidnas. In each case there was a prominent fibrous mass < or = 12 cm in diameter enclosing plerocercoids, which were surrounded by an intense inflammatory infiltrate dominated by plasma cells and lymphocytes, with focal suppuration. Multiple, small (< or = 2 mm) plerocercoids were present in the lungs and pleural cavity of a fourth echidna that died due to severe pneumonitis. Several plerocercoids also were found in the lung of a platypus (Ornithorhynchus anatinus) associated with parenchymal compression and focal pneumonia.
Animals↗
The geographic distribution and host range of Capillaria hepatica (Bancroft) (Nematoda) in Australia.
The geographic distribution, host range and prevalence of Capillaria hepatica were recorded in 4629 house mice, Mus domesticus, 263 black rats, Rattus rattus, and 58 Norway rats, R. norvegicus. The parasite was found at five localities, all in or near large towns along the coast. The two Rattus species appeared to be the primary hosts of C. hepatica in Australia. Published and unpublished data on helminth infections of Australian native mammals from 1162 murids (26 species), 3018 marsupials (67 species) and 99 monotremes (two species) were compiled. Only seven animals from three murid species were infected with C. hepatica; all were from the same rainforest in northern Queensland. C. hepatica was distributed widely, occurring in the house mouse, black rat and Norway rat on a 10,850 ha farm but there was no infection in cattle, sheep or goats (abattoir records). Also, 52 rabbits, four cats and one fox (shot samples) and 27 marsupial mice, Sminthopsis crassicaudata (museum specimens), had no sign of C. hepatica infection. Overall, the results indicate that transmission of C. hepatica to native, domestic and feral mammals is rare, presumably because of ecological constraints on egg embryonation and survival. In the light of these findings, the potential use of C. hepatica as a biological agent to control mouse plagues in Australia is discussed.
Animals↗
Can the nematode Capillaria hepatica regulate abundance in wild house mice? Results of enclosure experiments in southeastern Australia.
The hypothesis that a liver-inhabiting nematode, Capillaria hepatica, can regulate abundance of the house mouse (Mus domesticus) was tested in enclosures, in southeastern Australia. Changes in mouse abundance, and the relationship between mortality and host abundance were compared in three treatment and three control populations. Any effect of C. hepatica on mouse abundance was masked by an unknown regulating factor(s). This factor(s) caused density-dependent mortality in the control and treatment populations and, together with strong seasonal trends in parasite transmission, confounded our test of the ability of C. hepatica to regulate the abundance of house mice. The seasonal trends in transmission have important implications for the potential of this parasite as a biological control agent and for models of the interaction of C. hepatica and mouse populations. Transmission of C. hepatica apparently occurred throughout the 18 month study, further supporting its potential as a biological agent in the control of mouse plagues in this region.
Analysis of Variance↗