The Notice of the
talk at The Wharf, Tavistock, has been moved to the
News page.
On a light note, I found this tick-related /
public health video on YouTube recently: The
Wood Tick Song
............. and "No" it is not me!
An interesting article about
ticks from Knock News, "Just
a Tick ..." was added 10 Apr 2011.
Electron
microscope images
Tick Awareness Factsheet - Dartmoor National Park Authority
Dartmoor CAM - Ticks
page
More information about ticks
- the forerunner of this web site
Diagram showing
the relative size of tick stages
on the human finger nail.
Image reproduced with permission
from Lyme Disease Action
Click here
to see a photograph of real-life life-cycle stages - at bottom of this page
Mission Statement - what it's about
"To increase knowledge and
understanding of ticks on Dartmoor and its margins, bearing in mind that they carry diseases that affect health and that various factors -
e.g. milder winters, changing hill farming practice, fewer animals, less grazing, less
trampling, less swaling, spreading bracken, greater leisure use etc. - may
cause ticks to have a greater impact on human and animal health in the future."
Aims - aspirations
-
To run the project to the end of 2009.
-
To involve as many
people as possible who encounter ticks.
-
To collect as many ticks as possible.
Objectives - deliverables
-
To identify the species
of ticks that occur on and around Dartmoor.
-
To record geographical
locations where ticks are found.
-
To record and measure
life cycle stages through the year
- larvae, nymphs and adults.
-
To investigate if larvae
and nymphs occur late in the year.
-
To investigate if ticks
are active in winter.
-
To photograph ticks, their life cycle stages
and identifying features.
-
To put photographs on
the project's web site.
-
To update the web site
with results as they accrue.
-
To share the findings with interested individuals or bodies.
-
To thank the sponsors
and collectors who have made the project possible.
Additional objective:
-
To ascertain the number
of Dartmoor ticks carrying Lyme disease
Preliminary results: 1 tick in 20 found to carry spirochaete bacteria
The following have moved to the Photos pages:
The IDSA Washington Lyme disease hearings and
webcast links have moved to the
Disease statistics page.
Dartmoor tick indices
1, 2, 3
Using worst case scenario figures where there were two
samplings in a given month
The highest risk of encountering ticks is where
the lower index numbers
indicate the closer distance between ticks on the ground. The worst times were:
|
High Moor: |
May/Jun & Oct |
|
Bracken: |
Apr/May & Sep |
|
Sheltered valley: |
May to Oct inclusive |
| |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
Open
grassland
(High moor) |
n/s* |
None |
None |
7.3 |
4.2 |
3.9 |
10.5 |
15.8 |
15.8 |
9.5 |
None |
None |
Bracken
(Edge of high moor) |
n/s* |
13.1 |
4.6 |
4.8 |
3.9 |
7.9 |
6.2 |
10 |
6.2 |
9.1 |
None |
None |
Woods
(Sheltered valley) |
7.5 |
4.5 |
6.7 |
3.4 |
1.0 |
1.2 |
2.1 |
1.3 |
1.3 |
2.8 |
6.7 |
6.4 |
* n/s - not sampled
1
Index = shortest distance between ticks assuming equal distribution on a square
grid.
2
Tick numbers are reduced by low temperature, very wet or very dry conditions
- under these conditions, they seek shelter in the ground cover
micro-climate to conserve moisture.
3
There are reasons to believe that these
numbers are under-estimates of tick numbers,
see here.
|
Talks about Ticks & Lyme disease
- an increasing threat to health?
Talks for groups such as Women's Institutes, Scouts,
Guides, Schools etc.
are available in the Devon and Cornwall area. The titles at
present are:
-
"Ticks & Lyme disease"
-
"The Dartmoor Tick Watch Project"
-
"A tick can make you sick�"
- two levels, aimed primarily at school children and young persons.
Sample slides .....
If you are interested, please see contact details
below
|
This project is a private undertaking by a retired
scientist to investigate the number, distribution and variety of ticks occurring on
and around Dartmoor.
If you see ticks in the area in your work or leisure activities,
please join in!
Ticks occur across the United Kingdom, from
the highlands of Scotland to the centre of London. To see where they have
been officially recorded, click on the interactive distribution maps for sheep
tick (here)
and hedgehog tick (here).
Some ticks harbour disease organisms that can
seriously affect human and animal health. The incidence of e.g. Lyme disease,
the commonest UK tick-borne disease, appears to be increasing (see here).
The trigger for the project was finding six
ticks on a dog after a day on Shaugh Moor, an area not then indicated for the tick on
the interactive tick maps that are linked below.
British ticks recorded in the
South Devon area (includes Dartmoor)
* Ixodes ventalloi moved
to this table following the identification of one tick
from the Ivybridge area by the Health Protection Agency's Tick Recording Scheme,
pending second official identification.
�
Bites people
|
Argas reflexus |
Pigeon tick, Canterbury
tick, a soft tick |
� |
|
Hyalomma marginatum |
Two-host tick |
� |
|
Haemaphysalis punctata |
Red sheep tick, coastal red
tick, |
� |
Ixodes acuminatus
includes Ixodes dorriensmithi
& Ixodes guernseyensis |
Southern rodent tick, in SW |
� |
Ixodes apronophorus
includes Ixodes arvicolae |
Marsh tick, East Anglia |
|
Ixodes arboricola
includes Ixodes passericola |
Tree-hole tick, in SW |
|
|
Ixodes caledonicus |
Northern bird tick |
|
|
Ixodes canisuga |
Fox tick, Dog tick in SW |
|
|
Ixodes rothschildi |
Puffin tick,
in SW |
|
|
Ixodes unicavatus |
Cormorant tick - coastal, maybe SW |
|
|
Ornithodorus maritimus |
Marine argasid, a soft tick,
coasts - Irish |
� |
|
Rhipicephalus sanguineus |
Kennel tick, brown dog tick |
� |
Other British ticks
Total of twenty-eight species names, some are aggregated together.
�
Bites people - Information from Ticks - A lay guide to a human
hazard by George Hendry & Darrel Ho-Yen,
Mercat Press, Edinburgh,
1998, ISBN 1873644 809.
The hyperlinked species names in the
tables above link to interactive distribution maps
at the NBN - National Biodiversity Network
via the NBN Gateway
The gaps in the maps may reflect the lack of
recorders in those areas.
When I started this project, I knew of six
cases of Lyme disease among friends or friends of friends. I have recently heard
of a dog that died from Lyme disease. I have currently heard of 49 cases among
mostly local people.
Tick numbers on Dartmoor may be increasing.
This could be due to an interplay of several factors:
It is said that ticks are increasing
everywhere, if this is true then Dartmoor users are perhaps suffering a "multiple whammy"
because of the factors above. The risk of tick-borne disease is foreseen as
increasing (here).
Further, there are more people using Dartmoor,
so the risk of tick infections increases overall. It is reported that perhaps 5%
to 30% of ticks are infected and that a tick needs to be attached for 24 hours
to pass on any infection.
One problem is that some life cycle stages are
small and can be easily overlooked. Also, removing a tick incorrectly, in a
manner that stresses it, can induce regurgitation of pathogens into the victim's
body thereby causing infection.
The project provides
containers to keep ticks in for examination
and measurement by microscopy and photography so as to identify types and life
cycle stages.
A short data sheet
is included, asking date and where and what the tick was found on: this entails 'ticking' tick-boxes!
The results will be freely available via this
web site and should be of general interest to any person or body with an interest in
Dartmoor. They will also be forwarded to the national
Tick Recording Scheme (see more details
here).
If you are interested or can help by carrying a small plastic
container that
weighs nothing and takes up little room, please contact:
Dr Keith Ryan BSc, PhD, CBIOL, FRSB, FRMS
11a Gower Ridge Road
Plymstock
Plymouth
PL9 9DR
Tel. 01752 405245
email:
(clickable image, anti-spam)
My qualifications
Thirty-five years running light and electron microscopes in biological
research,
1969-2004. Elected to Membership of the Institute of Biology, 1971, and
Fellowship of the Royal Microscopical Society, 1972. Award: Geoffrey Meek
Memorial Prize (Roy. Microsc. Soc.) for technical advances in microscopy, 1988.
Presentations: 72, Publications: 57.
Adult female common sheep tick, Ixodes ricinus
also called Castor
Bean
Tick, Pasture Tick & Wood Tick
Total body length - capitulum ("head") plus idiosoma ("body") is 3.5 mm.
The hard scutum (dorsal shield) does not cover
the whole body
as it does in the male tick,
this allows for body swelling during feeding prior to egg-laying.
"Deer Tick" is reserved
for the American Ixodes scapularis
where
it is
also called the Black-legged Tick
See also:
Ticks page on
Dartmoor CAM for more information
about ticks and tick-borne diseases.
0 to 10 = 1.0 mm. Each small division = 0.1 mm.
Ixodes ricinus mouthparts.
Note the backward-pointing barbs
on the central component (the 'hypostome')
between the two lateral palps, this anchors the tick during feeding.
This view is from the dorsal surface.
The relative sizes of stages in the Sheep Tick (Ixodes
ricinus) life cycle
|
Key to the images |
|
larva (unfed, 0.75 mm) |
male (unfed, 2.1 mm) |
female (engorged, 8.72 mm) |
|
nymph (unfed, 1.34 mm) |
|
female (unfed, 3.2 mm) |
|
nymph (engorged, 3.6 mm) |
Composite of photographs taken at the same
magnification (x6)
The scale marks on the left and bottom edges are 1 mm
divisions on a steel ruler photographed at the same magnification (x6). The on-screen magnification is x17 on an 800x600 pixel
screen display.
(Engorged larvae, with 6 legs, can be seen HERE)
|
Web site created 26 June 2008
©2008-2014 Keith Ryan - All rights reserved except for "Results" data
Additional: In 2022, Keith sadly died, passing several websites onto Simon Avery to keep them hosted, including this one. It is kept for future interest and information.
Any enquiries about copyright or re-use, please contact Simon Avery
|
