LUNGWORM IN LAMBS.

Otago Witness, Issue 1916, 10 August 1888, Page 6

LUNGWORM IN LAMBS.

By D. M'Gregoe, Enfield, Oamaru.

During the past few years this parasitic disease of the organs of respiration has attracted considerable attention from farmers and entomologists all over the world, and although the researches have not resulted in any agreement as to the nature I and habits of these creatures, they have added materially to our previous limited knowledge regarding them. There are many varieties of the strongylus, or lungworm, and it is thought that the chief habitat of the ! species is the sea, for many varieties of thread-like worms which are found in the i gills of fish* and the lungs of the porpoise III I and the dolphin, have been found alive in the j intestines of various kinds of birds. Some i varieties of lungworm live in damp earth. Professor Ercalani bred them in damp earth, kept them alive, and saw them reproduce several generations; and he found that when at liberty the worms that became parasites could not be distinguished from those that did not. Lungworm has been found in nearly every kind of animal, wild and tame, high and low. Even serpents are subject to it. The lungworm of the frog can live in damp earth, and differs from the lungworm of the toad. There is a slight difference between the lungworm of each animal, but there is no proof that they are not of the same species, and only assume a different form when undergoing the various stages of development in the different animals through which they pass. We need not be surprised at this, for we know that the fluke of the sheep, hare, deer, and ox differ from each other, but yet is the same creature. All internal worms have to go through a longer or [ shorter period of migratory existenoe as young and sexless creatures or as larv.-c. They at the same time change their host many times. The lungworm that concerns us i nost is IHS STRONGYLUS FILABIA OF THE SHEEP. 1 his worm was discovered many years ago. Dr Cobbold, a distinguished M.D., F.R.S, anc practical microscopist, took numerous I embryos from the windpipe of a dead calf, and placed them in finely sifted earth. The mould was rich, and was moistened with water: Twenty-four hours ' afterwards living embryos were found moving.' about amongst the, earth. Moist and high temperature imparted activity to them, but, on the other hand severe frost did not destroy life. During the following six months occasional examinations of . the embryos in the| soil were made, and only very slight changes were found to take place, such as a small increase of length. Dr Cobbald is of opinion that this is strong proof the embryo can only advance to maturity in the breathing organs of some animal such as the calf or lamb. When examining >the finely ' sifted soil a small earthworm that had found its way into it by accident was discovered ; and to ascertain if the worm had swallowed any of the experimental embryos, the lower end of ' its body ' was cut off and in it was found lungworm ova and embryos. These were considerably more developed than those in the finely sifted earth. This suggested a possibility that the earthworm might be one of the intermediate hosts to the lungworm. Fresh earthworms were .then examined, and many of them found infested with the embryos of the lungworm. Those found in the body of the earthworms were placed in dew drops similar"'to those that o neuron the blades of grass in low-lying pasture. This last experiment showed that when once the creatures escape from tb.6

body of their intermediate host — the earthworm— they grow with amazing rapidity a nd display powers of motion such as would enable them to crawl up the wet grass or clown, the air passages of the lungs. In the production of disease in farm stock what geem to be 'at least five different species of lungworm are concerned. In some instances more than one species affect the same animal, but it is thought that this difference may be caused by the hosts through which the embryos pass when undergoing their stages of development— some having passed through the earthworm and others through the lizard, or some such creature. It is in the last and most perfect form that insects perpebuabe the species. The lungworm of the sheep exists in the proportion of one male to 50 or GO females ; and it has been estimated that the female carries as many as 300,000 embryos and eggs. The eggs of most kinds of worms resist the action of strong chemicals, and have been known to produce young after serving the purpose of study for many years. The lungs o£ a sheep frequently contain 40 or 50 female worms — mere packages of eggs. When coughed up these find their way into the body of the earthworm, and there undergo a higher degree of development. We may, consequently, look for lungworm where earthworms are most plentiful. Earbh is the natural food of the earthworm, but they eat many kinds of leaves, such as cabbage and lettuce. They are cannibal, and eat their dead. They can live many months under the water, but pass the winter arid very dry weather singly or rolled up into halls at the bottom of their burrows. This would account for the sheep in very dry or very cold climates not being so much troubled with lungworm as those in lowlying, damp situations. In some warm localities, after a shower in the morning, earthworms are so plentiful that 4 it seems as if there had been a shower of them. The embryo lungworm on these occasions escapes from their bodies and crawl up the web grass, returning to the earth in all probability as the grass becomes dry. Thus a whole locality would soon be overrun with lungworm embryos. The richer the soil the more numerous the earthworms, and as a natural sequence the more subject are sheep to lungworm.

The prevailing opinion is that all the small creatures creeping on the earth help to spread the disease, and that no pasture can be said to be free from ib. The gastric juice ib is thought destroys them all with the excepbion of a chance one which creeps up the nostrils ab a time when the digesbive powers are weak, and consequently the gastric juice out of order; and immediately the gastric juice returns to ibs natural activity the worms are expelled by, the increased quantiby of carbonic acid thrown off through the lungs as a consequence of active digestive powers. Providing that the digestive powers are restored to their natural activity before the worms have had time to set up inflammation, the trouble is easily overcome. The dauger to life is only in cases where the digestive powers become weaker and weaker through the animals being kept too long on bad water and foul pasbure, which fail to yield up some one or other of the. ingredients that are essential bo keep the digestive organs in an active, healthy state.

Since the first appearance of this disease in the colony a number of patent medicines have been brought forward, and tonics made from native herbs recommended, as well as the remedies used in the Old Country. At first sight one is surprised to find that each and all of these is more or less useful. We shall see further on, however, whether any one of them is ofmore value than even asingle day on sweet, clean pasture ; when it will be shown that they are worse than useless so long as the confidence that is put in them at present is continued. Chief among the remedies is salt.

The principal advocates of this substance reside in London. Their argument seems to rest on the alleged fact that sheep never suffer from internal parasites when there is always abundance of salt within their reach, and then point to the Australian sallbush districts and the saltmarshes in the Old Country as being free from these diseases in proof of their assertions. Now there is a large saltmarsh at the mouth of the Shag river, and the tide flows above the Bushy railway bridge, and in that marsh, nevertheless, I have seen hoggets dead with lungworm actually beside " pools of sea water, every pint of which is said to contain an ounce of (pure salt. On the Kartigi beach the tide flows under the railway bridge, and causes a swamp in the paddocks above. I have examined dead lambs there, and found they had died from lungworro. Mr Buckland, of Waikouaiti, a practical sheepfarmer whose farm is nearly surrounded by the sea, with plenty oC acres; to the beach, was amongst the fiivt in (bo colony to recommend turpentine and oil as a remedy for lungworm.

To collect information on this point I communicated with several shepherdb emploj'ed on farms whoso sheep have aeo^s to tho sea all the year round. One ot them in tbo North Island wrote to me to the effect thab their hoggets had access to the beach ever since they were lambed, and yet outoflOOO weaned last year they had skinned 1500 and had thrown^a number of the, carcasses into the sea, for they nearly all died beside tbo water. He further states that they hai' been dosed twice with turpentine and oil. On some of the farms around Hastings from 25 to 50 per cent, of the hoggets were lost, nothwithstanding that there was rock salt always within reach.

On farms where the water is hard sheep do not salt, for such water contains carbonate of magnesia, sulphates, and other salts. In rain water these are almost entirely absent, and consequently salt would bo useful. first power is exerted on tho digestive organs, the stomach aud the inteswnes, augmenting the escretion and quickening the energy of each. It would be entirely useless to force salt in large quantities on animals, for there is a provision in the economy for the immediate excretion through the urine of any superfluity of this substance, so that it is prevented from accumulating to to an undue extent in the body. No doubt salt is useful in its way, but as a remedy for {ungworm too much confidence is beiner put mit. l Next week I shall deal with fumigation, the turpentine cure, &c.