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Any parasite relies on survival of the animal
in which it lives in order to survive itself. It is therefore not normal for
a parasite to lead to the death of the host in which it lives. Under normal
circumstances parasite and host will live in a balanced harmony. The
exception arises when the normal hosts resistance against the parasite, which
usually keeps it's infestation under some semblance of control, is reduced
allowing the parasite to gain the upper hand. Such situations arise when wild
birds are short of food, following migration, accident, injury or during
extended periods of inclement weather. For the falconer's bird training,
chilling, accident, or other causes of stress may trigger off the same
situation. There are exceptions to this rule, where even a small number of
parasites can cause disease; this arises where the parasite only needs to
live in that host for a short period, in order to complete a life cycle, this
done he does not mind if the host becomes diseased and dies. Recently parasitic
diseases have been increasing in incidence in captive bred birds, this is as
a consequence of increased levels of exposure to the parasite, as a
consequence of increased contamination of the aviary by the parents. External Parasites A large ecto parasites infestation on a bird is typically a sign of the bird being ill for other reasons, as any fit bird will usually control it's own parasites. So rather than treating the parasite |
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alone, one should always look for a further
cause of illness. Hippoboscids (keds or flat flies) are perhaps
the commonest parasites of raptors. They are blood suckers, although they
rarely cause any significant blood loss. There is however now evidence to
suggest that they can and do carry blood borne parasites between one bird and
another. In particular the blood parasites 'Leucocytozoon', 'Plasmodium,
'Sarcocystis' as well as other blood borne infections. In the United Kingdom
such blood borne parasites are rare, however in warmer climates such as USA
diseases such as malaria are highly significant. After the warmer summers of
1994/95, the incidence has increased, affecting birds aged 3-5 months, to
date owls (especially snowy), Harris Hawks and Gyr Falcons have been
affected. In one case, the affected bird had caught a magpie only nine days
earlier, which had a heavy infestation of hippoboscids, in time it became
evident that these had carried a blood parasite infestation, which caused a
dramatic and fatal infection of the Harris Hawk in a very short time. Lice are also a common ecto parasite of
raptors. Lice feed off skin debris and feathers, they do not however survive
off the host for long, and hence treatment with routine insecticide
preparations is relatively easy. Conversely Dermanyssus gallinae the 'Red
Poultry Mite', does |
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survive off the host for considerable periods.
This mite lives in crevices in the wood work and usually only comes out at
night to feed, as such a feather plucking bird may appear free of parasites
when examined during the day, whilst the same bird is crawling with them at
night. Any ecto parasite which actually sucks it's
hosts blood can be easily and readily controlled by use of the cattle wormer
'Ivomec' (MSD AgVet), however this will need to be diluted, doses and
suitable diluants can be arranged by your veterinary surgeon. Other ecto parasites are best controlled by
the use of insecticides, however great care must be taken that only safe
preparations are used. Some sprays contain either active ingredients or
propellants, which can lead to toxicity or irritation to the air sacs. The
new cat and dog flea preparation Frontline' has proved safe and effective in
over 100 birds on which we have used it. It appears to be not only more
effective but also far safer than previously recommended ectosparasite
preparations. Internal Parasites Many bird keepers, falconers and
rehabilitators simply worm their birds annually or when they are handled and
believe that all is then well. This concept is seriously flawed, and can on
occasions lead to serious repercussions. Fluke: fluke are a relatively common although
usually non- |
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pathogenic parasite of raptors. They may
inhabit the small intestine or the bile ducts. Diagnosis is made only on
faecal examination, and although usually non-pathogenic, when found treatment
should be given. The drug which is most commonly used is rafoxanide at a dose
of 1Omg/kg, or praziquantel (droncit) 5-10mg/kg daily 14 days or chlorsulon
(Curatrem) 20mg/kg by mouth 3x at 2 week intervals. Both the diagnosis,
advice on treatment and the drug will be available from your vet. Tapeworms: tapeworms are a relatively common
parasite, but are rarely pathogenic. Clinical illness will only occur in
situations in which there is very heavy infestation, which can lead to an
obstruction of the small intestine. Treatment is by the use of Praziquantel
(Droncit, Bayer), which is available in injection or tablet form, and birds
should be dosed at 5-10 mg/kg or chlorsulon as above. Roundworms: these are the largest and most
significant group of endo parasites. The group includes the 'Syngamus
trachea' and 'Serratospiculum sp" which affect the wind pipe, and air
sacs respectively. Both will cause respiratory signs in infected birds,
however in both cases it is particularly important that the diagnosis is made
prior to treatment being given. In the case of Syngamus even after the worms
are killed they will remain in the airways for up to six weeks slowly rotting
away causing respiratory signs and occasionally pneumonia in the meantime. |
