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ABSTRACTThree species of Parastrongyloidespreviously described from the small intestine of Australian marsupials are reviewed and redescribed from new material and in some instances new host species: P. australisMawson, 1960 from Isoodon obesulusand Perameles gunnii; P. peramelisMackerras, 1959 from I. macrourus, Perameles nasutaand Perameles gunnii; and P. trichosuriMackerras, 1959 from Trichosurus vulpecula vulpecula, T. vulpecula johnstoniand Petaurus breviceps. In addition, three new species of ParastrongyloidesMorgan, 1928 (Nematoda: Rhabditoidea: Strongyloididae) are described from the small intestines of their hosts: P. nadgeensisfrom the agile antechinus, Antechinus agilis, the dusky antechinus, A. swainsonii, and the fat-tailed dunnart, Sminthopsis crassicaudata; P. timbillicensisfrom the white-footed dunnart, S. leucopusand S. crassicaudata; and P. walteraefrom the small intestine of A. swainsonii. Three additional suspected species are partially described from the southern long-nosed bandicoot, P. nasuta; the northern quoll, Dasyurus hallucatus; and the little-long-tailed dunnart, S. dolichurabut not named. A key to the species of Parastrongyloidesfrom Australian marsupials and a monotreme is presented.

ABSTRACTThe parasitic nematode communities are described from the oesophagi and stomachs of eastern grey kangaroos, Macropus giganteus(Shaw), red-necked wallabies, Notamacropus rufogriseus(Desmarest) and swamp wallabies, Wallabia bicolor(Desmarest) (Marsupialia: Macropodidae) from coastal and montane habitats in southeastern New South Wales. The number of nematode species recorded for each macropodid species was similar to that recorded in previous studies in Victoria. Overall diversity of nematode communities was greatest in N. rufogriseusand greater in montane than in coastal localities in both N. rufogriseusand M. giganteus. Community similarity between coastal and montane localities was highest in N. rufogriseuscompared to M. giganteusand W. bicolor. Few nematode species were shared between host species. There were more significant differences in species prevalences than intensities of infection in M. giganteusbetween coastal and montane localities, less so for N. rufogriseusbut these were not calculated for W. bicolordue to small montane sample size. Community differences between macropodid species were attributable primarily to host-specific parasite species. This is the first comparison of helminth communities in macropodids in a replicated study in different habitats at similar latitudes.

ABSTRACTTwo new species of ParastrongyloidesMorgan, 1928 (Nematoda: Rhabditoidea: Strongyloididae) are described, P. tachyglossi, from the small intestine of the short-beaked echidna, Tachyglossus aculeatus(Shaw, 1792) from southeastern New South Wales and northern Queensland and P. caenolestifrom the small intestine of the common grey or dusky shrew opossum, Caenolestes fuliginosus(Tomes, 1863) from Parames du Puruce, the Republic of Colombia. The two new species are distinguished from each other by the position of the two pairs of caudal papillae of P. tachyglossiimmediately pre- and post-cloacal in contrast to those in P. caenolestiwhich are distant from the cloacal aperture and by the generally smaller sizes of males and females of P. caenolestiand the presence of a minute terminal papilla or spine on the tail tip of male P. tachyglossi. They are distinguished from seven of the eight known species of Parastrongyloidesby the absence of a single, median, dome-shaped papilla anterior to the cloacal opening in males and by the number and distribution of the other pre- and post-cloacal papillae in the male. The eighth species, ParastrongyloidesskrjabiniPetrov & Savinov, 1959 has no pre- or post-cloacal papillae. These represent the first species of Parastrongyloidesto be described from a monotreme and from a South American marsupial.

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ABSTRACTChagas disease is endemic in Latin America and an emerging infectious disease in the United States. No effective treatments are available. The TcG1, TcG2, and TcG4 antigens are highly conserved in clinically relevant Trypanosoma cruziisolates and are recognized by B and T cells in infected hosts. Delivery of these antigens as a DNA prime/protein boost vaccine (TcVac2) elicited lytic antibodies and type 1 CD8+T cells that expanded upon challenge infection and provided >90% control of parasite burden and myocarditis in chagasic mice. Here we determined if peripheral blood can be utilized to capture the TcVac2-induced protection from Chagas disease. We evaluated the serum levels of T. cruzikinetoplast DNA (TckDNA), T. cruzi18S ribosomal DNA (Tc18SrDNA), and murine mitochondrial DNA (mtDNA) as indicators of parasite persistence and tissue damage and monitored the effect of sera on macrophage phenotype. Circulating TckDNA/Tc18SrDNA and mtDNA were decreased by >3- to 5-fold and 2-fold, respectively, in vaccinated infected mice compared to nonvaccinated infected mice. Macrophages incubated with sera from vaccinated infected mice exhibited M2 surface markers (CD16, CD32, CD200, and CD206), moderate proliferation, a low oxidative/nitrosative burst, and a regulatory/anti-inflammatory cytokine response (interleukin-4 [IL-4] plus IL-10 > tumor necrosis factor alpha [TNF-a]). In comparison, macrophages incubated with sera from nonvaccinated infected mice exhibited M1 surface markers, vigorous proliferation, a substantial oxidative/nitrosative burst, and a proinflammatory cytokine response (TNF-a » IL-4 plus IL-10). Cardiac infiltration of macrophages and TNF-a and oxidant levels were significantly reduced in TcVac2-immunized chagasic mice. We conclude that circulating TcDNA and mtDNA levels and macrophage phenotype mediated by serum constituents reflect in vivolevels of parasite persistence, tissue damage, and inflammatory/anti-inflammatory state and have potential utility in evaluating disease severity and efficacy of vaccines and drug therapies.

New strategies to control infection with Mycobacterium tuberculosis, the causative agent of tuberculosis, are urgently required, particularly in areas where acquired immune immunodeficiences are prevalent. In this report we have determined if modification of the current tuberculosis vaccine, Mycobacterium bovis BCG, to constitutively express the mycobacterial HspX latency antigen altered its protective effect against challenge with virulent M. tuberculosis. Overexpression of M. tuberculosis HspX in BCG caused reduced growth in aerated cultures compared to control BCG, but growth under limited oxygen availability was not markedly altered. Upon infection of mice, BCG:HspX displayed tissue- specific attenuation compared to control BCG, with reduced growth within the lung and liver but not the spleen. Both BCG:HspX and control BCG protected mice against aerosol M. tuberculosis challenge to a similar extent, however, immunodeficient mice infected with BCG:HspX survived significantly longer than mice infected with the control BCG strain. Therefore, altering the in vivo persistence of BCG by overexpression of HspX may be one important step towards developing a new tuberculosis vaccine with an improved safety profile and suitable protective efficacy against M. tuberculosis infection.

A strain of Mycobacterium bovis BCG that secretes high levels of functional murine monocyte chemotactic protein 3 (BCGMCP-3) was developed. Mice vaccinated with BCGMCP-3displayed increased lymphocyte migration in vivo and augmented antigen-specific T-cell responses compared to mice vaccinated with BCG alone. The level of protection afforded by BCGMCP-3was equivalent to that with control BCG; however, immunodeficient mice infected with BCGMCP-3survived significantly longer than mice infected with the control BCG strain. Therefore, BCGMCP-3may be a safer alternative than conventional BCG for vaccination of immunocompromised individuals.

ABSTRACTA strain of Mycobacterium bovisBCG that secretes high levels of functional murine monocyte chemotactic protein 3 (BCGMCP-3) was developed. Mice vaccinated with BCGMCP-3displayed increased lymphocyte migration in vivo and augmented antigen-specific T-cell responses compared to mice vaccinated with BCG alone. The level of protection afforded by BCGMCP-3was equivalent to that with control BCG; however, immunodeficient mice infected with BCGMCP-3survived significantly longer than mice infected with the control BCG strain. Therefore, BCGMCP-3may be a safer alternative than conventional BCG for vaccination of immunocompromised individuals.

Ixodes tasmani is one of the most common and widespread of the Australian species of Ixodes and a vector of zoonotic rickettsial diseases. The tick was reared successfully in the laboratory; the entire life cycle was completed in 4 months. A diurnal rhythm of detachment from captive hosts (laboratory Rattus norvegicus) was observed for all stages and, combined with other evidence, suggests that I. tasmani is nidicolous. The prevalence and intensity of tick infestation on wild-caught, common brushtail possums (Trichosurus vulpecula), was least during the summer months. To investigate questing activity, laboratory-reared nymphs were held in enclosures in one sheltered (tree hollows) and three exposed (vegetation) microhabitats. Questing was continuous but at low intensity in tree hollows, and nocturnal and at an increased (higher) intensity in vegetation. The observed questing activity appeared to maximise host contact with T. vulpecula, which is nocturnal but retires by day to tree hollows. Field and laboratory observations suggest that the risk for humans of tick-bite from I. tasmani and consequent transmission of zoonotic diseases may be low compared with the risk from other tick species.

This study describes the helminth community in 28 Rattus leucopus, from Australia, Papua New Guinea and Papua (formerly Irian Jaya), and compares the community in Australian R. leucopus with those known from two other Australian endemics, R. sordidus and R. fuscipes. In total, 28 parasite species were found: one acanthocephalan, five cestodes, one trematode and 21 nematodes as well as two lots of unidentified spirurid nematode larvae. The diversity of helminths in R. leucopus was high but equitable; the reciprocal of Simpson's Index was 1.75. The distribution of prevalence of helminth species was not indicative of a core-satellite structure. No species occurred at a prevalence >30% and more than half the species occurred at prevalences of <10%. Only 10% of the helminth species identified were unique to R. leucopus. Helminth community structure in R. leucopus differed from that observed in R. sordidus and the community in R. fuscipes was markedly different from those in R. leucopus and R. sordidus. Determinants of the diversity of the helminth community in R. leucopus include the time intervals between the three waves of migration of Rattus spp. to Australia, biogeographic factors related to immigration and adaptive radiation of the host genus, and associated with coevolution, speciation and host switching of the helminths.

Abstract The ectoparasites of northern quolls, Dasyurus hallucatus, are reported from 79 animals live-trapped at Kapalga Research Station, Kakadu National Park, during 1992–95. The ecto- and endoparasites are reported from 62 dead D. hallucatus during the same period; these were mostly road-kills collected from an 88-km section of the Arnhem Highway between Jabiru and the Northern Entry Station of Kakadu National Park. Tissues from 28 of the road-kills were examined histologically. Additionally, 214 scat samples were examined for ecto- and endoparasites. Seven species of ectoparasite, including two species of tick, a larval trombiculid mite, a louse and two (possibly three) species of flea, and 17 species of endoparasite including a trematode, a larval cestode, 13 species of nematode, a larval pentastome and a protozoan were recorded from D. hallucatus. Sarcocystis sp. was found in tissues but neither Toxoplasma gondii nor Trichinella pseudospiralis were detected in histological sections or tissue digests. Ticks, mites and nematodes were found in scats. The tick Haemaphysalis bancrofti, the flea Echidnophaga aranka and possibly E. ambulans, and the nematodes Mackerrastrongylus peramelis and Cylicospirura heydoni represent new host records for D. hallucatus. Although parasitism was common in D. hallucatus, few individuals harboured large burdens. Consequently, it appears unlikely that parasitism is a major factor contributing to the decline of northern quolls in this region.

As part of the National Weather Service (NWS) Modernization and Restructuring Program, WSR-88D (NEXRAD) Doppler radar installation has been completed at each Weather Service Office in Florida. Recently, this powerful new tool provided unique opportunities for Jacksonville, Tampa Bay, and Melbourne NEXRAD Weather Service Office personnel to investigate tropical cyclone (TC) rainbands for evidence of tornadogenesis.

ABSTRACT One hundred and sixty‐nine patients who underwent repeated myocardial revascularization surgery between 1982 and 1987 were studied. The mean interval between operations was 91.6±7.3 months. The indications for repeated surgery were graft failure in 37.2% of patients, progressive coronary atherosclerosis in 40.2% of patients and a combination of the two causes in 22.5% of patients. The mean number of grafts that were inserted was 2.74±0.61 grafts per patient at the second operation. Coronary end‐arterectomy as an adjunctive procedure was necessary in 17.1% of patients. The hospital mortality rate was 4.1%, with a 1.8% incidence of perioperative myocardial infarctions. Of the surviving patients, 96.3% were available for follow‐up at a mean of 19±6.4 months. Of these patients, 68.5% were well and could be categorized into the New York Heart Association's functional class I. We conclude that both progression of coronary atherosclerosis in native vessels and obstruction of venous grafts cause recurrent angina and that repeated myocardial revascularization surgery is a feasible treatment option in these patients.

SummaryFasciola hepatica infection was found in 5 of 12 marsupial and 1 of 3 eutherian species examined in southeastern Australia. Prevalence ot infection in native mammals was as follows; Macropus gigantcus, 59%; M. rufogriseus banksianus, 15%; Wallabia bicolor, 5%; Vombatus ursinus, 30%; Trichosurus vulpecula, 5%; and Rattus fuscipes, 4%. Collection sites were assigned to one of two categories. Prevalence was higher in macropodids collected on agricultural pastures grazed by sheep and cattle (category A) than in macropodids collected in forested areas variably grazed by livestock (category B). A high prevalence of infection (82%) was recorded In M. giganteus in an area from which sheep and cattle had been excluded for 15 years. Prevalence of F. hepatica infection in V. ursinus was similar in be two habitat categories; however, within forested areas infection was more common in V. ursinus collected near swamps and creeks than those taken from drier ridges. The presence of habitat suitable for the snail intermediate host, Lymnaea tomentosa, and Utilization of this habitat by domestic and native mammals are important epidemiological factors. Moderate numbers of flukes (1–95) and faecal egg production (1-195 eggs per gram of faeces(EPG)) in M. giganteus and M.r banksianus emphasize their suitability as hosts and contaminators of pasture. Small numbers of flukes and conspicuous hepatic lesions in V. ursinus suggest moderate resistance to infection. The low prevalence and small number of flukes in T. vulpccula was attributed to the arboreal habit of this host. R. fuscipes is susceptible to infection but infected individuals were found in only one of numerous forest areas with suitable snail habitual. Feeding behaviour is probably responsible for the absence of F. hepatica infection in W. bicolor and Rattus lutreolus in forested areas.Australian Journal of Experimental Biology and Medical Science (1981) 59, 713–721; doi:10.1038/icb.1981.62

The aim of this study was to compare the efficacy and toxicity of prophylactic OKT3 and equine antithymo-cyte globulin when each drug was administered for a similar duration after heart transplantation. Forty-one patients (35 males, 6 females; mean age 46±2 years) were randomized to receive either OKT3 for 10 days (20 patients) commencing within 24–48 hr of transplantation or ATGAM for 8 days (21 patients) commencing on the day of transplantation. All patients were maintained on triple-agent immunosuppression with prednisolone, azathioprine, and cyclosporine. The two groups were well matched with respect to age, sex distribution, pretransplant cardiac diagnosis, and donor heart ischemic time. Mean duration of follow-up was 14 months (range 9–19 months): Actuarial survival at 12 months was 83±9 in the OKT3 group and 81±9 in the ATG group (P=NS). Mean time to first cardiac rejection was 33±8 days in the OKT3 group compared with 27± 5 days in the ATG group (P=NS). Linearized rejection rate did not differ between the two groups at any time point up to 12 months posttransplant. Viral infections were significantly more common in the OKT3 group: 1.6±0.3 vs. 0.8±0.2 infections per patient (P<0.05). Adverse reactions were more common in patients who received OKT3 prophylaxis and included three patients who developed acute respiratory distress, two of whom required assisted ventilation. In conclusion, prophylactic OKT3 and ATGAM result in comparable rejection rates and survival when administered for a similar duration after cardiac transplantation. OKT3, however, is associated with increased morbidity due to a higher incidence of adverse reactions and of viral infections.

Cytokine induction of calcium-independent nitric oxide synthase is associated with production of large amounts of nitric oxide (NO). NO is a free radical that is rapidly degraded to nitrite and nitrate. Measurement of plasma and urinary nitrate is an indirect marker of NO production and previous studies have demonstrated that plasma nitrate rises with allograft rejection. The purpose of this study was to examine the temporal relationship between the rise in urinary nitrate excretion and the onset of graft rejection, and to determine the effect of conventional immunosuppression on nitrate excretion. The heterotopic model of cardiac transplantation in the rat was used, with Brown-Norway to Lewis allografts and Lewis to Lewis isograft controls. Twenty-four-hour urine specimens were collected before and after transplantation. Urinary nitrate excretion was measured by gas chromatography/mass spectrometry. Each group was treated with (1) no immunosuppression, (2) dexamethasone (3 mg/kg), or (3) CsA (10mg/kg) on days 0,1, and 2. Time to rejection for untreated allografts was 5.1±0.1 days, extending to 8.4±0.5 and 9.6±0.4 days with dexamethasone and CsA treatment, respectively. There was a significant rise in nitrate excretion on days 4, 7, and 9 for control, dexamethasone-treated, and CsA-treated allografts, respectively, preceding evidence of rejection. Untreated allograft rejection was associated with a peak in nitrate excretion 8 times that of basal excretion by isografts. Treatment of the allografts with dexamethasone and CsA significantly attenuated peak nitrate excretion compared with untreated allografts with a only a 2- to 3-fold rise preceding rejection. Results indicate that allograft rejection is associated with a dramatic increase in peak urinary nitrate excretion that is attenuated by standard immunosuppressive therapy. An increase in nitrate excretion precedes evidence of graft rejection, and may serve as a noninvasive marker of graft rejection.

Thirty-nine patients required heroic resuscitative measures for sudden hypotension and cardiac arrest in the first 72 hours following cardiac surgery between January 1, 1984 and May 31, 1988. Emergency sternotomy with open cardiac compression was performed in twenty-four of these patients when external cardiac compression failed. These were categorised as Group A. Group B comprised the fifteen patients in whom resuscitation was entirely by means of external compression and adjuvant measures. Survival with NYHA Functional Class I and II status was noted in 75% of patients in Group A, compared with 20% in Group B (P <0.002). Emergency sternotomy with open cardiac compression is an effective way of resuscitating patients in the intensive care unit in the first few days following open heart surgery.

Nitric oxide production is increased in allograft rejection and may have both beneficial and deleterious effects on graft function and survival. In animal models, conventional immunosuppressive agents have been shown to decrease nitric oxide production. The aim of our study was to determine what effect augmentation and selective inhibition of nitric oxide production may have on graft survival by using the model of heterotopic cardiac transplantation in the rat. L-Arginine, the naturally occurring substrate for nitric oxide production, was administered subcutaneously at 200 mg/kg/day. L-NG-monomethyl-L-arginine (L-NMMA) is a selective inhibitor of nitric oxide synthase and was administered at 500 mg/kg/day to allograft recipients from the day of operation. Endogenous nitric oxide production was quantified by analysis of urinary nitrate excretion, and time to rejection was determined by graft palpation. L-Arginine did not significantly alter urinary nitrate excretion by iso- or allografts, suggesting that nitric oxide production is not a substratelimited process in this model. Graft survival in this group was unchanged. L-NMMA produced a small increase in graft survival from 5.1±0.1 to 6.3±0.3 days compared with control allografts (P0.001) and abolished the rise in urinary nitrate excretion seen with control allografts. Lower doses of L-NMMA produced dose-related decrements in urinary nitrate excretion, but did not alter graft survival. We found that allograft rejection can proceed to graft loss despite complete inhibition of the increase in nitric oxide production that occurs during untreated rejection. The small increase in graft survival suggests that nitric oxide plays a minor role as a cytotoxic effector molecule in this model of acute rejection.

ABSTRACTSequential immunization with mycobacterial antigen Ag85B-expressing DNA and Mycobacterium bovisbacille Calmette-Guerin (BCG) was more effective than BCG immunization in protecting againstMycobacterium tuberculosisinfection. Depletion of the CD8+T cells in the immunized mice impaired protection in their spleens, indicating that this improved efficacy was partially mediated by CD8+T cells.