A National Tick Paralysis Forum has been held with the support of Merial Australia Pty Ltd, and is being co-ordinated by Elizabeth Court (BVSc MACVSc MVetClinStud, Veterinary Technical Services, Merial Australia). A survey of participating veterinary practices is to commence in September 1998. Survey written and approved by the National Tick Paralysis Forum which met for the first time in May 1998. Key veterinarians and scientists met at the Forum to discuss methods of controlling tick poisoning, and to work out ways of distributing this information to veterinarians. A detailed prospective questionnaire was determined to be a sound method for collecting information with the objective of publishing the results in an Australian Scientific Journal.
Update- Mar 2000. The 2nd Forum was held Feb 28-2000. The findings of the prospective national tick paralysissurvey were discussed.Some questions were answered, some myths apparently debunked and new questions were raised. The resultsand discussion will be submitted for publication.Major issuesincluded: what dose of antiserum?, what dose (if any) of acepromazine?, how do we manage pulmonary oedema?, how do we manage oesophageal dysfunction?,how important is ventilatory support? New research concerning the effectsof tick poisoning on myocardial contractility was presented by Dr Fiona Campbell(Univof Qld).
See also the University of Technology Sydney site at UTS- tick vaccine. Research is led by Associate Professor Kevin Broady, Immunobiology Unit in the Department of Cell and Molecular Biology.
Update- July 99. A recombinant form of the toxin that was not toxic but originally appeared in experiments using miceto be highly immunogenic and protective did not show the same paralysis-protection in dogs, although it was still highly immunogenic. Overall, this would seem to indicate that the original recombinant toxin used was not in the correct conformational state (ie. not properly "folded") to induce protective antibodies. The toxin gene needs to be expressed in a different way. Further funding is required to continue this useful research. It looks like a viable vaccine is still some years away. (paraphrased from email by Prof Kevin Broady, courtesy Peter Griswold).
Update- Jan 2000. The tick paralysis vaccine project,while it addresses an important Australian problem, has not beenable to attract any public or government research funding andonly a small amount of commercial funding. So to date thisresearch has been performed by postgraduate students as research projects. Because the project is now at such an advanced stageProf KevinBroady may instigate a university-based company to develop the vaccine thisyear (2000) with the aim of having aproduction available for the 2001 tickseason. (paraphrased fromemail by Kevin Broady, courtesy Sally-Ann Edwards).
Update- June 2000. Very recently an MSc student has expressed the toxin in a different system and shown the recombinant toxin reacts with the antibodies in the commercial anti-tick serum. This suggests that the folding problem has been overcome. Further testing with this product is underway. The project is in a good position but there is always more work to do before a vaccine can be released to the public. (paraphrased from email by Kevin Broady)
Update- Oct 2000. Ticks are being sought to carry out clinical trials necessary before the vaccine can be released to the public. There are still many unanswered questions about the function and structure of the neurotoxin which need to be worked out to permit future improvement of the vaccine. Contact details are Matt Padula (BSc, PhD student, Tick Research Unit, UTS, and Assoc Prof Kevin Broady, Head, Tick Research Group, Dept of Cell and Molecular Biology, University of Technology, Sydney, Westbourne St, Gore Hill, Sydney NSW 2065, tel 02 9514 4101 , fax02 95144026.
Biology of Ixodes holocyclus and the related species, Ixodes cornuatus. PhD thesis by Jackson J - University of Melbourne.
An electrophoretic comparison of the Australian paralysis tick, Ixodes
holocyclus Neumann, 1899, with I. cornuatus Roberts, 1960 (Acari :
Ixodidae) Janey Jackson (AC) , Neil B. Chilton (A) , Ian Beveridge (A) ,
Michelle Morris (B) and Ross H. Andrews
(A) Department of Veterinary Science, University of Melbourne, 250 Princes
Highway, Werribee, Vic. 3030, Australia.
(B) Department of Microbiology and Immunology, University of Adelaide, GPO Box
498, Adelaide, SA 5000, Australia.
(C) To whom correspondence should be addressed. email: j.jackson@vet.unimelb.edu.au.
Abstract: An electrophoretic study was conducted on ticks morphologically identified as either Ixodes cornuatus or I. holocyclus from Tasmania and several localities on mainland Australia. Ticks were characterised genetically at 27 enzyme loci encoding 24 enzymes. The extent of genetic divergence (52-69% fixed differences) between ticks from Tasmania and those from the mainland was equivalent to that found between these two groups and two morphologically distinct species, I. hirsti and I. fecialis. The Tasmanian ticks therefore represent a different species from the specimens from the mainland and the electrophoretic data show that the morphological characters currently used to distinguish I. holocyclus from I. cornuatus are inadequate. Genetic heterogeneity was detected in samples from different localities on the mainland. This could represent either population variation, or the existence of cryptic species, but more ticks from these mainland localities need to be examined electrophoretically to resolve this. Australian Journal of Zoology, 1998, 46, 109–117 © CSIRO 1998 0004-959X/98/020109 Australian Journal of Zoology: www.publish.csiro.au/journals/ajz Published by CSIRO PUBLISHING for CSIRO and the Australian Academy of Science Enquiries: The Managing Editor, Australian Journal of Zoology, CSIRO PUBLISHING, PO Box 1139 (150 Oxford Street), Collingwood, Vic. 3066,Australia.Telephone +61 3 9662 7622; fax +61 3 9662 7611
Population genetics of the Australian Paralysis Tick Ixodes holocyclus (honours project). Matthew Shaw. BSc at the University of Queensland. Honours at the University of Queensland. It has been suggested by some workers that there are different forms of this species. This suggestion has not been tested using genetic data. The aim of this project is to survey populations along the Eastern seaboard of Australia, assessing the level of inter-population variability in ribosomal DNA. Various regions are being amplified, currently the D1 of28S rRNA, ITS1 and ITS2.Once enough regions have been amplified with PCR and sequenced, then phylogenies can be constructed in order to test for the existence of distinct regional forms. It is intended to use Ixodes cornuatus as an outgroup for this analysis.
A tick antiserum dose/response study by Coralie Endean, veterinarian working in the Animal Emergency Centre in Brisbane - 2 year retrospective study using three parameters- staging, dose and outcome to try to work out a dose/survival curve.
Blood gases in tick paralysis- masters research project by Chris Jensen, veterinary surgeon practicing in The Gap, Brisbane.
Developing an ELISA assay to measure the anti-toxin activity of the dog serum used to treat paralysed animals. By Rogan Lee, Department of Parasitology The University of Queensland, Brisbane, 4072. Australia. Tel: 07-33652572 Fax: 07-33651588
Fiona Campbell (University of Queensland). Measurements of myocardial function before, during and aftertreatment for tick paralysis. Parameters included thoracic X-Rays, ultrasound, ECG, PCV, and assays of cortisol and adrenaline. Research has found evidence of myocardial depression, pulmonary oedema and rising PCV. Systemic hypertension was found not to be a major problem. Respiratory distress was found to be related more to pulmonary oedema and muscular fatigue than to central respiratory depression. Dr Rick Atwell believes that treatment for left-sided heart failure should be considered in all tick cases- eg using vasodilators and diuretics and supplemental oxygen (when it can be delivered in a stress free manner).
Kirsten Ingwersen, student in Veterinary Microbiology at theUniversity of Sydney, is also involved with Lyme Disease investigation at the Microbiology Dept at Royal North Shore Hosp,Sydney. Dr Henry Collins of the University of Sydney is also involved with this study.
Ben Davidson. Veterinary Specialist Centre, Sydney. Using Swann-Ganz and arterial catheters to measure blood pressure, blood gases, pre-capillary wedge pressures on naturally occurring cases of tick paralysis.
Natalie Steen. Presentation at Australian College of Veterinary Scientists, Scientific Meeting, July 2003.
Anna Fearnley. Presentation at Australian College of Veterinary Scientists, Scientific Meeting, July 2003.
Sonja Hall. ELISA Parasitology (Tick Paralysis Research Group, 2003).
Daniel Schull. Tick Antiserum reactions. (Tick Paralysis Research Group, 2003).
Sarah Toole. Clinical Cases - QT (Tick Paralysis Research Group, 2003).
Trish Clark. Therapy Choices (Tick Paralysis Research Group, 2003).