External Parasites of Poultry

New Zealand Journal of Agriculture, Volume 78, Issue 1, 15 January 1949, Page 47

External Parasites of Poultry

TN common with other livestock, poultry are afflicted with various external parasites, such as lice and mites, which, though not usually very serious if occurring in only small numbers, may cause considerable loss if allowed to multiply unchecked. In this article A. C. Howse, Poultry Veterinary Officer, Department of Agriculture, Wellington, describes some of the 'commoner external parasites of poultry and the measures which should be taken to control them.

LICE are among the commonest external parasites with which poultry are affected and are well known to most poultry farmers. They are small, flat insects which live and feed on the surface of the skin, where they can be seen running about with great activity if the feathers are parted, particularly in the region of the vent. Those on fowls are biting lice, and feed not by sucking blood but on fragments of skin and surface debris. The entire life cycle is spent on the body of the host, where the female parasite lays eggs which are attached to the feathers near where they issue from the skin. In heavy infestations numerous clusters of these , eggs, or nits, can be seen at the bases of the feather shafts near the vent, resembling masses of sugar in appearance. The eggs hatch 5 to 7 7 days after they are laid, and the young lice which issue become mature about 2 weeks after hatching. Their . biting causes considerable . irritation, restlessness, and loss of condition in the birds. Unless, they are watched for, by frequent handling and examination of birds, they may easily escape detection. . The most convenient . method of treating. lice on poultry is . fumigation

with nicotine sulphate in 40 per cent, solution by painting a thin line of the solution along the upper surfaces of the perches about half an hour before the birds go to roost. The heat of the birds’ bodies vaporises the nicotine during the night so that the fumes rise among the feathers and poison the parasites. Care should be taken that only a4O per cent, solution.of nicotine sulphate is used and not the pure form of the drug, which is much too powerful and will poison not only the lice but also the fowls. The house should be reasonably well ventilated, but not to such an extent that an adequate concentration of vapour is prevented. When an ' openfronted . house is to be fumigated a quiet night with no wind should be chosen and, if practicable, part of the open front should be blocked with sacking. This treatment should not be carried out in houses - which have been, lime .washed recently, as the lime causes excessive vaporisation of the nicotine and may make the fumes too powerful. The fumigation has no effect on lice eggs, so the treatment must be repeated at least once after an interval

of 8 to 10 days to kill lice which hatch out subsequently. The solution is highly poisonous, so care should be taken that it is kept out of the reach of children and other irresponsible individuals. Where only a small number of birds is kept they can be dusted with sodium fluoride, but that entails catching and treating each bird. The powder should be dusted well into the feathers so

that it comes in contact with the skin, and this treatment also should be repeated 8 to 10 days later. Red Mite Another common parasite is the red mite, a minute, 8-legged creature, related to the itch mite which causes itch or scabies in man, to the parasites which cause mange in dogs and other animals, and to scab in sheep. Though known as the “red” mite, the parasite is normally grey and appears red only when engorged with blood. Most poultry keepers have seen these parasites, as they are very common. They breed very rapidly, so that a heavy infestation can be built up in ' a short time and may escape detection if the poultry keeper is unobservant. ; , The parasites feed intermittently, and when not feeding they hide in cracks and crevices in the houses and at the ends , of perches, where they can be seen in enormous numbers as minute red or grey specks, according to whether or not they are engorged with blood. If a perch in an infested house is removed, large numbers of parasites will be seen in the socket, and in and near the same place will be a fine, x silvery powder, consisting of the shed skins of the parasites, which change their outer covering

from time to time. At night they leave these hiding places to crawl along the perches and on to the fowls, where they cause irritation and loss of condition by sucking blood.

Fortunately infestations, though common, can be dealt with easily by spraying the inside of the house with either kerosene or creosote, taking particular care to see that the. liquid thoroughly penetrates all crevices and perch sockets. Perches should always be detachable, and the ends should be well soaked in the . liquid, the whole perch also being sprayed. Creosote has the advantage that it preserves the woodwork as well as destroying the mite, but it makes -the interior of the house very dark. If it is used, it is as well to paint or spray the outside of the house with it at the same time, or mites may 'retreat before the advancing tide of destruction and escape. . The house being then thoroughly coated with preservative, a double purpose will have been served. For the destruction of the parasite similar considerations apply to treatment with kerosene, but apart from that spraying the outsides of houses with kerosene would serve no useful purpose and would be extremely , expensive.

A male common poultry louse.

After the house has been treated the birds can be given a single fumigation with 40 per cent, nicotine sulphate, as described for lice, to destroy any mites which were on them at the time and thus escaped the spraying.

Recent overseas experiments in which houses infested with red mite were sprayed with D.D.T. are reported to have achieved most promising results, one spraying with a 1 per cent, solution having been sufficient to destroy heavy infestations. The D.D.T. apparently has a powerful after-effect, killing any mites ' setting foot on sprayed surfaces for , a considerable time after they have been treated. It is rather early at present to recommend this for general use, but if it becomes possible to try it in New Zealand, the results may be reported later. . ( To prevent red mite infestation the first consideration' is to ensure that the house is 'well lit by adequate window space and, where possible, by whitewashing of the inside walls. Dark and dismal interiors favour the development of the parasites, which dislike strong light. Of almost equal importance is having all perches detachable so that they can be removed and inspected frequently and treated if necessary. 1 An infestation can build up very rapidly without being noticed, so a sharp watch should be kept for the mites.

Scaly Leg

A form of mange, scaly leg is caused by a very small 8-legged itch mite which burrows and feeds under the scales' of the legs. It is similar to scabies of man and mange of dogs and cats, which are also caused by mites burrowing under the skin. In scaly leg the parasite spends all its time on the infested bird, breeding and laying eggs in the tunnels and channels caused by its burrowing, where the eggs hatch and the young mites grow to maturity. The irritation which results is intense, causing loss of condition, sometimes lameness, and the formation of powdery crusts beneath and between the scales, which are raised from the surface, causing the legs to look thicker than normal. Fortunately the parasites which cause this trouble are easily destroyed. A common and well-known remedy is to dip the legs of affected birds twice or three times a week in ordinary kerosene, which will penetrate the damaged tissue and kill the mites. If time permits, it is better first to soak the legs in warm, soapy water to soften the crusts and scales and assist penetration by the kerosene. As kerosene is rather severe in its effects, the use of 1 part of kerosene to 2 parts of raw linseed oil is safer, and even that is extremely irritant, so care should be taken that it does not get on the skin of the leg above the scales or on any other part of the body.

If the kerosene is applied every few days, usually a cure is soon effected. A watch should be kept to see that the condition does not recur, but no further trouble should be experienced if it has not gone too far in the first instance.

A female red mite, greatly engorged with blood after feeding (much magnified).

Depluming Scabies

Another form of mange, depluming scabies occurs extensively overseas and may cause trouble, in New Zealand. It results from the activities of another very small itch mite which lives and feeds at the bases of the feathers, causing such intense irritation that the affected bird pulls out its own feathers, though other causes may also result in fowls losing their feathers. If the existence of this form of mange is established, generally it yields readily to repeated applications of sulphur ointment, obtainable from any chemist, and made by mixing 1 part of finely-divided sulphur thoroughly with 4 parts of petroleum jelly or lard.

" This article, though by no means complete, covers most of the external parasites which commonly affect poultry. Anybody desiring further information, or help with a particular case, should communicate with the Department of Agriculture Veterinarian for the district or with the Poultry Instructor. In case of a serious outbreak of poultry disease the owner should communicate with the Poultry Veterinary Officer, Department of Agriculture, P.O. Box 3004, Wellington.