scholarly journals Viral haemorrhagic disease of rabbits and human health

1998 ◽  
Vol 121 (2) ◽  
pp. 409-418 ◽  
Author(s):  
J. A. CARMAN ◽  
M. G. GARNER ◽  
M. G. CATTON ◽  
S. THOMAS ◽  
H. A. WESTBURY ◽  
...  

Viral haemorrhagic disease of rabbits (VHD), a potential biological control for wild rabbits in Australia and New Zealand, escaped from quarantined field trials on Wardang Island and spread to the mainland of Australia in October 1995. This study looked for any evidence of infection or illness in people occupationally exposed to the virus. Two hundred and sixty-nine people were interviewed and 259 blood samples were collected. Exposures to VHD-infected rabbits ranged from nil to very high. No VHD antibodies were detected in any of the 259 sera when tested by VHD competitive enzyme immunoassay, which had been validated with 1013 VHDV-specific antibody negative sera. A questionnaire designed to elicit symptoms of disease in a range of organ systems found no significant differences between illness in those exposed and those not exposed to VHD, nor could an association be found between exposure and subsequent episodes of illness. The findings are consistent with the view that exposure to VHD is not associated with infection or disease in humans.

2016 ◽  
Vol 69 ◽  
pp. 258-262
Author(s):  
B. Smith ◽  
S.G. Casonato ◽  
A. Noble ◽  
G. Bourd?t

Californian thistle (Cirsium arvense) is a problematic weed particularly in permanent pastures The fungus Sclerotinia sclerotiorum has potential as a bioherbicide to control this weed but its variable efficacy in historical field trials suggest that there are differences in susceptibility to S sclerotiorum within the species To test this hypothesis the responses of 32 New Zealand provenances of C arvense to a foliageapplied myceliumonbarley preparation of S sclerotiorum were compared under common conditions Significant differences between provenances were found supporting the hypothesis that there is variation within C arvense in New Zealand in its susceptibility to S sclerotiorum Further work will examine differences in the efficacy of fungal isolates against different C arvense provenances


2002 ◽  
Vol 29 (6) ◽  
pp. 627 ◽  
Author(s):  
Ben Reddiex ◽  
Graham J. Hickling ◽  
Grant L. Norbury ◽  
Chris M. Frampton

The impact of predation and rabbit haemorrhagic disease (RHD) on population dynamics of rabbits, and the survival of juvenile rabbits, was investigated between July 1999 and March 2000 in North Canterbury, New Zealand. Rabbit abundance and pre- and post-emergent rabbit mortality were monitored on four sites, two of which were subject to predator control. RHD spread naturally through all sites from late November to early December. Rabbit densities declined on all sites, but after the RHD epidemic, declines were significantly greater where populations of predators had not been controlled. Survival of rabbit nestlings was lower where predators were not controlled. All post-emergent radio-collared rabbits died at sites where predators were not controlled, whereas 18% of those collared at sites where predators were controlled survived to maturity. In contrast to the results from previous studies, rabbits born at the start of the breeding season had very high rates of post-emergent mortality, as they appeared to be susceptible to the RHD virus later in the breeding season. The age at which juvenile rabbits become susceptible to RHD, the timing of RHD epidemics, and the abundance of predators are likely to be important in determining survival of juvenile rabbits. This study demonstrates that predation can reduce rabbit populations to low levels, but only in combination with other factors, in this case RHD.


Holzforschung ◽  
2003 ◽  
Vol 57 (3) ◽  
pp. 237-242 ◽  
Author(s):  
B. W. Held ◽  
J. M. Thwaites ◽  
R. L. Farrell ◽  
R. A. Blanchette

SummaryAlbino strains ofOphiostoma floccosum,O. piceaeandO. pluriannulatumwere selected and screened for biological control of sapstaining fungi on New Zealand radiata pine (Pinus radiata). Albino strains were obtained through matings and single ascospore isolations from cultures of prevalent species in New Zealand. These strains do not synthesize the melanin-like hyphal pigments of common sapstaining fungi. Additional mating studies were also carried out to obtain isolates ofO. piceaeandO. floccosumthat lacked pigmented fruiting structures. Several albino isolates ofO. piceaewith colorless synnemata and isolates ofO. floccosumwith little to no synnemata were obtained. Biological control potential of the albino isolates was evaluated in the laboratory by challenging them on wood chips with fungi that cause extensive sapstain in pine,Leptographium procerum,Ophiostoma piliferumandSphaeropsis sapinea. Many albino isolates ofO. floccosum,O. piceaeandO. pluriannulatumwere effective in stopping the challenge fungi from staining wood chips and were fast growing and colorless when grown unchallenged on wood chips. Selected albino isolates ofO. pluriannulatumwere used in two field trials in New Zealand to control sapstain. Several strains were found to significantly reduce dark sapstain as compared to the untreated control logs.


2014 ◽  
Vol 41 (2) ◽  
pp. 136 ◽  
Author(s):  
Carlos Rouco ◽  
Grant Norbury ◽  
Dave Ramsay

Context European rabbits (Oryctolagus cuniculus) are serious economic and environmental pests in Australia and New Zealand. Since the illegal introduction of rabbit haemorrhagic disease virus (RHDV) in New Zealand in 1997, the disease has persisted in most rabbit populations, with major epizootics occurring usually each autumn. Aims We evaluated the efficacy of the virus as a biological control agent in the southern South Island. Methods We used an index of rabbit abundance (kills per hunter) based on a region-wide annual rabbit-hunting competition to evaluate rabbit population trends 7 years before and 16 years after the first outbreak of RHD. We also evaluated the influence of rainfall and temperature in the preceding year on post-RHD trends in the index. Key results Kill rates declined by 60% following the initial epizootic. They remained low for the following 3 years and then increased steadily to intermediate levels punctuated by occasional declines. The instantaneous rate of increase in kill rates during the increase phase was low, but above zero (0.04 per year). No relationship between kill rates and rainfall was apparent, but there was a negative relationship between kill rates and winter temperature in the preceding season. Conclusions The kill-rate data obtained from this hunting competition suggest that RHD still appears to be killing rabbits. Every 2–3 years over the past decade, kill rates have been as low as they were when government rabbit-control programs were in place before RHD arrived, but the efficacy of RHD as a biological control agent is waning compared with the first outbreaks of the disease. This concurs with findings based on spotlight counts. Implications The data collected from this hunting competition are a good example of how ‘citizen science’ can be used to capture large volumes of pest-monitoring data from a wide geographic region for very little cost. The information is a valuable addition to understanding the effects of a major wildlife disease.


2009 ◽  
Vol 100 (2) ◽  
pp. 217-223 ◽  
Author(s):  
L.L. Fagan ◽  
A. McLachlan ◽  
C.M. Till ◽  
M.K. Walker

AbstractField trials were conducted at four Canterbury, New Zealand locations in 2005–06 to determine if the synergistic effects of biological control by natural enemies and standard drenching techniques controlled lettuce aphid populations throughout the entire growing season. Chemical usage significantly lowered aphid densities in the outer, wrapper and heart leaves compared to control plants at most times. However, in mid-summer, natural enemies, such as the brown lacewing (Micromus tasmaniae), 11-spotted ladybird beetle (Coccinella undecimpunctata) and small hoverfly larvae (Melanostoma fasciatum), were more than sufficient to control lettuce aphids without the use of insecticides. Drenching, in addition to natural enemy attack, appears to be required in early spring and late summer to maintain very low levels of lettuce aphid. Given the potential for imidacloprid resistance to develop, it may be advisable to restrict drenches to these key periods in order to allow populations of natural enemies to maintain control of prey populations. We recommend industry support the validation of action thresholds across different regions within New Zealand and focus on the seasonal biology of predators to assist growers with the sustainable long-term control of lettuce aphids. The inclusion of additional data into an economic model to compare pest damage with predator loading would be useful for growers in managing aphid problems. These results will assist in the continued improvement and development of a sustainable IPM strategy for lettuce aphids in New Zealand and elsewhere.


2013 ◽  
Vol 40 (2) ◽  
pp. 277-293 ◽  
Author(s):  
R. A. Galbreath ◽  
P. J. Cameron

The introduction of the eleven-spotted ladybird Coccinella undecimpunctata to New Zealand in 1874 has been widely quoted as the first importation of an insect for biological control in New Zealand and one of the first anywhere. However, searches of historical records show no evidence that such an introduction was made or attempted. Instead, there is clear evidence that the presently accepted record arose by a process of cumulative misreporting. An account of discussions in the Entomological Society of London in December 1873 about possible introductions of various beneficial insects to New Zealand was misreported by the American entomologist C. V. Riley, and several subsequent authors restated his version with further modifications and additions. This created the record of the introduction of C. undecimpunctata to New Zealand in 1874 that has been accepted and repeated ever since.


2003 ◽  
Vol 95 (4) ◽  
pp. 1656-1663 ◽  
Author(s):  
C. A. Rivera ◽  
M. H. Tcharmtchi ◽  
L. Mendoza ◽  
C. W. Smith

Hindlimb unloading (HU) is known to induce physiological alterations in various organ systems that mimic some responses observed after exposure to microgravity. In the present study, the effects of up to 4 wk of HU on the liver were assessed in male Wistar rats and two mouse strains: endotoxin-sensitive C57BL/6 mice and endotoxin-resistant C3H/HEJ mice. Plasma levels of endotoxin, a known stimulator of hepatic injury, were measured in portal and systemic blood samples. Endotoxin was elevated by ∼50% in portal blood samples of mice and rats but was not detectable in systemic blood. This low-grade portal endotoxemia was associated with hepatic injury in rats and C57BL/6 mice as indicated by inflammation and elevated serum transaminase activities. Blood levels of the cytokine TNF-α were increased by ∼50% in C57BL/6 mice; no significant elevation of this cytokine was detected in rats. Messenger RNA levels of the acute-phase proteins serum amyloid A, haptoglobin, and lipopolysaccharide binding protein were significantly enhanced after 3 wk of HU in endotoxin-sensitive rodents. In contrast, no histological changes or significant increases in serum enzyme activity were detected after HU in C3H/HEJ mice despite portal endotoxin levels of 222 ± 83.4 pg/ml. At the 3-wk time point, expression of acute-phase proteins was not elevated in C3H/HEJ mice; however, expression after 4 wk of HU was similar to endotoxin-sensitive rodents. In conclusion, these findings indicate that HU induced mild portal endotoxemia, which contributed to the observed hepatic injury in endotoxin-sensitive rodents.


1928 ◽  
Vol 19 (3) ◽  
pp. 317-323 ◽  
Author(s):  
J. G. Myers
Keyword(s):  

The biology of Rhyssa persuasoria, L., and of Ibalia leucospoides, Hochenw., has already been sketched in a preliminary paper published in this Bulletin (xix, pp. 67–77, pl. iii, 1928) in collaboration with Mr. R. N. Chrystal, of the Imperial Forestry Institute. The following observations were made by the writer chiefly at the Farnham House Laboratory, during the spring and summer of 1928, and are gathered together in view of his departure from England. The work of collecting and rearing supplies of Rhyssa and Ibalia for shipment to New Zealand, for the biological control of Sirex nodilio (juvencus), has been continued on a larger scale. The present notes were made incidentally during this work and are arranged under nearly the same headings as in the previous paper, to which they are supplementary. One error needs correcting. It was stated (on p. 75) that the larch (Larix europaea, D.C.) is indigenous, though actually planted in the Oxford locality mentioned. As a matter of fact, of course, larch, though Palaearctic, is not indigenous to Britain.


2002 ◽  
Vol 106 (2) ◽  
pp. 228-232 ◽  
Author(s):  
Joël L. Vanneste ◽  
Robert A. Hill ◽  
Stuart J. Kay ◽  
Roberta L. Farrell ◽  
Patrick T. Holland

Plant Disease ◽  
2021 ◽  
Author(s):  
Leslie Amanda Holland ◽  
Renaud Travadon ◽  
Daniel P. Lawrence ◽  
Mohamed Taieb Nouri ◽  
Florent P Trouillas

Almond trunk and branch canker diseases constitute a major cause of tree mortality in California. Numerous fungal pathogens have been associated with these canker diseases and pruning wounds act as major infection courts. Prior to this study, there were no products registered in California for the management of these diseases. In this study, fungicidal products including synthetic chemistries, biocontrols, paint and a sealant were evaluated for preventing fungal pathogen infection via pruning wounds. In four field trials conducted over two dormant seasons, sixteen pruning wound treatments were tested using hand-held spray applications, against five almond canker pathogens, namely Botryosphaeria dothidea, Neofusicoccum parvum, Cytospora sorbicola, Ceratocystis destructans, and Eutypa lata. The fungicide thiophanate-methyl (Topsin M) provided 82% overall disease prevention against four fungal pathogens. The biological control agent, Trichoderma atroviride SC1 (Vintec), tested at three application rates, resulted in 90 to 93% protection of pruning wounds in field trials, and for individual pathogens ranged from 81-100% protection for the three rates. At the time of this publication, Vintec is being considered for registration as a biological control product for the prevention of almond canker diseases, while Topsin M is recommended to growers for the prevention of almond canker diseases. This research indicates that effective protection of pruning wounds from infection by almond canker pathogens can be achieved with a one-time spray application of thiophanate-methyl or the biocontrol, T. atroviride SC1 (recommended 2 g/liter) after pruning.


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