By Dr Colin Walker BSc, BVSc, MRCVS, MACVSc (Avian health)
The parasitic worms drain the birds of
nutrition, in the process compromising both health and race performance.
External parasites such as lice and mites directly damage the feathers.
Control of parasites is therefore vital to the long-term success
of the loft. At times, both the information and the enormous array
of products available to the fancier can be a bit confusing and so
what are the important parasites and what are the current preferred
medications available to control them.
The important parasites are basically roundworms, hairworms, tapeworms
and lice and mites. Roundworms and hairworms live in the digestive
tract of the pigeon, releasing eggs, which are passed in the droppings.
After several days, they become infective and, if then accidentally
ingested by a bird, hatch in the bowel and grow into a new worm.
This new worm then grows into an adult and then produces more eggs.
This whole lifecycle can be completed as quickly as 3 weeks. In
both the racing and breeding lofts, the number of round- and hairworms
should be absolutely zero. This can be achieved by worming twice
at a 3-week interval and each time following up with a super-thorough
clean of the loft. If it is not possible to totally clean the loft,
then worming should be repeated every 3 weeks for at least 6 months.
Worm eggs cannot survive in the environment for more than 6 months,
and treating for longer than this therefore means that there are
no further infective eggs in the environment to reinfect the birds.
Worm infection is diagnosed by microscopic examination of droppings.
Droppings should be regularly checked by a veterinarian or animal
technician. If reinfection occurs from introduced birds, returning
racebirds or strays, the above protocol should be repeated.
Tapeworms have a different and fascinating lifecycle. The adults
live in the bowel, burying their heads deep in the bowel wall and
feeding off body fluids. Behind the head stretches a ribbon-like
body that is divided into segments. These segments are called egg
packets or proglottids. As they mature, one or more of these segments
break off from the end of the body and are passed in the droppings.
Once in the environment, the egg packets need to be eaten by an
insect to become infective. Pigeons, in turn, become infected by
eating one of these insects. Tapeworm infection does not require
a microscope to diagnose, as the egg packets in the droppings are
visible. Most are about the size of a grain of rice and are white
to pink in colour. Often a fancier will notice that a bird is a
bit quiet and that its droppings are a bit loose. Close examination
will reveal the small white glistening egg packets in the droppings.
With tapeworm infection, the birds just need to be treated once
but the loft should be sprayed with a safe long-acting insecticide
(the preferred one is Permethrin) to minimise the chance of the
birds eating more insects. The droppings in the loft should then
be monitored during cleaning to ensure that infection does not
For roundworms and hairworms, these days there is no reason to
use anything else than an avermectin such as Ivermectin (‘Ivomec’)
or Moxidectin. These medications are just so safe and effective
and of course have the handy side-effect of also killing all external
parasites that suck blood. This includes all mites. Do, however,
watch your dose rate. Not all Ivomec is the same. It comes in a
variety of strengths. Some large-volume bottles that seem really
cheap are probably a fairly dilute preparation. One needs 10 mg
of active drug per litre of drinking water for the medication to
be effective. To figure out how much to add to the drinking water,
multiply the strength on the label by what will become the dose
to equal 10. For example, a common strength available is 0.8 mg/ml
(0.8 g/litre). 0.8 x 13 equals approximately 10. So therefore,
one needs to add 13 ml to 1 litre to give an effective dose. Similarly,
a brand that is 5 mg/ml will only need 2 ml per litre to be added
to the drinker.
All avermectins are well tolerated and the birds can be fed and
loft flown routinely. These medications can also be used safely
during breeding, racing and moulting. In overdose, the birds will
become quiet and some may vomit. However, with withdrawal of the
drug the birds become normal in 1 – 2 days.
Some fanciers will notice that some worming preparations contain
piperazine. This is an older drug that rarely gives 100% clearance
of worms and because it has been used a long time some worms are
totally resistant to it. Products based on levamisole – and
a number of liquids and tablets are available – have the
strong disadvantage that food need to be withdrawn for at least
12 hours before and 6 hours after treatment and even then many
birds will still vomit. This makes it very hard to use during racing.
Wormers based on fenbendazole and mebendazole cause huge frets
to form in the feathers if used during moulting and are not conveniently
packaged for use in birds.
When using avermectins to treat mites remember that all mites
that infect birds are not always found on them at any one time.
Many live in the nooks and crannies throughout the loft. Unless
the loft is also treated they quickly reinfect the birds. At the
same time as treating the birds with Ivomec or Moxidectin, spray
the loft to avoid this. Simply scrape the loft out as you normally
would and then spray a diluted insecticide (Permethrin is best)
on to the scraped surfaces and into the cracks and crevices. Done
on a warm day, the loft will be dry in 1 – 2 hours and the
birds can be called back in. Try and do such a loft treatment in
the morning so as to ensure the loft is completely dry by night.
Tapeworms are best treated with praziquantel. This drug is very
safe and like the avermectins can be used at any time of the pigeon
year. During treatment the birds behave normally and can be loft
flown and fed normally. Praziquantel is available in tablet form
and also as a water-soluble solution called Prazivet. Prazivet
tends to be fairly bitter and so often it is better to give each
bird 0.25 ml of the neat solution individually to each bird in
the back of the throat.
Lice live off feather debris and so the avermectins have limited
effectiveness against them. When lice are a problem, it is necessary
to spray or dip the birds. As lice live always on the bird, treating
all birds simultaneously will rid the loft of these. Whatever you
do, do not use any of the older preparations such as Malawash.
These are based on organophosphates. Organophosphates have a very
narrow safety margin in birds and accumulate in their system to
their detriment. Having a fancier ring the clinic in a panic after
using Malawash or a similar product, with birds dead or dying,
happens all too commonly. Organophosphates are absorbed through
the skin and as long as the birds remain wet continued absorption
will occur. Often fanciers have been lucky and have earlier dipped
on a warm day and have had the birds dry quickly. Dipping on a
cooler day means the birds stay wet for longer and absorb more
of the poison. This prolonged skin absorption coupled with a narrow
safety margin tips the birds into a toxic dose range. If a drug
company attempted to register an organophosphate for use in birds
these days they would have no chance. The few such products that
are on the market are therapeutic dinosaurs. Birds with organophosphate
poisoning lose muscle control, start to salivate and vomit, develop
diarrhoea, become unconscious and die. If overdose occurs, it is
important to prevent further absorption by physically washing the
birds. If the birds don’t start to improve immediately, your
veterinarian has an antidote injection. Birds regularly washed
in organophosphates gradually accumulate the poison in their system.
The drug, although quickly absorbed, is only slowly released and
tends to be stored in the body, particularly in the body fat and
bones. From here, it is gradually released, interfering with a
number of metabolic processes. This is particularly so in hens,
in which reproduction is affected, leading to abnormal ovulation
and abnormal egg shell formation.
These days use a synthetic pyrethroid such as Permethrin. These
are very safe yet just as effective as organophosphates, prevent
reinfection for up to four months and do not take the bloom off
the feathers. To spray the birds, dilute (usually 10 –20
ml per litre ) into a handheld pump bottle and spray the birds
liberally. To dip the birds, pick a warm day, fill a bucket with
warm water, add Permethrin at the rate of 10 –20 ml per litre
together with a wetting agent (e.g. some children’s baby
shampoo or a few shavings off a cake of pure soap such as “Velvet”)
and away you go. If done correctly, the vane of the feathers will
collapse back to their quills, exposing pink lines of skin. The
birds look like drowned rats but after spreading in the sun and
a bit of preening look normal in about 1 – 2 hours.
Obviously there is no single way of effectively clearing the birds
of parasites, but the system preferred by me is:
Moxidectin, 2 mg/ml, 5 ml per litre for 24 hours
Dip birds in Permethrin
Thorough clean of loft and spray loft with Permethrin
In tapeworm areas or if tapeworm segments are seen in droppings,
Prazivet, 0.25 ml to each bird.