HEALTH NOTES

Southland Times, Issue 20111, 23 February 1927, Page 10

HEALTH NOTES

GREATEST OF PESTS. RATS AND RAT-BORNE DISEASES. (Contributed by the Department of Health.) The rat throughout the ages has remained one- of the greatest of household pests. By their dissemination of disease, particularly bubonic plague, rats present a serious problem in preventive medicine. They create also great economic disturbance by the destruction of food and property. In Great Britain alone the consumption and waste of food stuffs in stacks, granaries, mills, warehouses, and shops, the damage to buildings, goods and merchandise, the destruction of poultry, and loss in other ways due to rats has been estimated to run into many millions of pounds annually. In New Zealand the financial loss from similar causes is undoubtedly very high. SPREAD OF DISEASE. During the decade of 1898-1907 plague caused the death of upwards of five million persons in India alone. It has from time to time swept Europe, and paralysed trade with appalling loss of life and money. This disease, especially the common or bubonic form, is spread by the rats. Rats also transmit infectious jaundice, rat-bite fever, dysentery, food poisoning, and several forms of parasitic worms, including trichinosis found in measly pork. Plague is essentially a disease, of rats, which only occasionally attacks the human race, and .is transmitted to human beings froin rats by the rat flea. In the early stages of an epidemic there is a heavy mortality among the rats, the rat fieas leave the dead rats, and infest those rats which remain, and so spread the disease. During an epidemic it is noticed there is a marked increase in the number of fleas found on each rat. Should a rat die, and there is no other rat available, the rat flea will attack the human being. Fleas breed in dust, particularly on dry earthen floors. Bare-footed persons are more susceptible to plague and the leg glands are those usually affected. This is one reason why Europeans -suffer more lightly from plague than their native brethren. In New Zealand during the years 1900-3 bubonic plague made its appearance, resulting in a few deaths.' In reference to this outbreak in 1900, a considerable mortality among rats was reported by a Medical Officer of Health of the Department of Health in the district around Mokau, which he suspected was of plague origin. It appears that the rats were migrating in a large body from the North; they suddenly invaded the district in question, and ahnost as suddenly disappeared but many sick and dead rodents were left in the train of the main band. On examination the rats obtained showed naked-eye and microscopical changes characteristic of •plague. In Auckland, where the fatal cases of plague occurred, dead rats obtained from wharves on examination showed that they had suffered from this disease. HABITS AND PREVALENCE. Rats are very cunning. They will move about in search of food. They will desert buildings where active measures are taken for their destruction and take up their abode with persons who leave them in peace. Here they will increase and multiply and use their refuge as a base of operations for raiding other buildings. They breed very rapidly, and the number of rats is only limited by the food supply and opportunities to nest. Few people have any conception of the enormous number in cities and on farms. Although few are seen in the daytime, at night they fairly swarm along the river fronts and walls, as well as in sewers, stables, warehouses, markets, and other places where food may be found. For instance, in 1901 an estate near Chichester, England, was badly infested with rats, 31,981 were killed by traps, poisons, and ferrets, while it is estimated that tenants at the threshing destroyed fully 5000 more. RAT DESTRUCTION. Considerable skill and experience is required to carry out an effective rat campaign. The rat is very wary, has a keen sense of smell, and unless precautions are taken he will become aware of the measures taken for his destruction and avoid them. It is therefore necessary that such measures should be sufficiently comprehensive to prevent rats finding a harbour outside the area of operation. The campaign should be in the hands of persons sufficiently skilled to make their work effective, such as an official rat-catcher. The most successful attacks on the rat population have been conducted by a combined effort under the control of the local authority. In order to successfully combat rats, it is necessary to make buildings rat-proof. (1) The basement should be impervious, i.e., bf asphalt, cement, or concrete. (2) Ventilating openings should be protected by wire. (3) Drainage openings should be protected and all drains carefully examined and tested. Rats use underground drains as thoroughfares and will readily connect their runs to any broken or defective drainage, or to an unprotected vent. (4) Food should be protected from rats. Rats come to a building primarily for the purpose of obtaining food. All stores should be kept in ratproof cupboards or bins. In large warehouses, bags and boxes should be so stored that there is a free space between the packages and the walls. Frequently passages should be made between the groups of packages, and the goods should be stored in frames sufficiently high above the floor to allow free movement for a cat. This space should be kept absolutely clean. All crumbs and refuse should be collected and placed in ratproof bins. Rats will hide and breed in accumulations of old sacks, bins, tins, and cases. They are very fond of paper for making their nests. POISONING. The use of poisons should be confined to granaries, stables, wharves, etc. Most rat poisons are dangerous to children and domestic animals, and greatest care must be exercised in their use. In laying poison baits, care must be taken first that the material is not touched by human hands as rats will not touch food that has been so handled. As far as possible, the grain or meal peculiar to the country or locality should be used to allay suspicion. Tallow, cheese, and fish are very popular with the rat family, and these can all be added to the baits. Most of the local authorities and chemists stock rat poisons, which can be obtained at a reasonable cost. In the home, traps, dogs, and the valiant cat are usually effective in dealing with this pest. Bear in Mind.—Rats not only cause great economic loss but spread disease, such as plague. The prevention and suppression of plague and other rat-borne diseases resolve themselves into a war upon these rodents. The appointment of official rat-catchers is an important step in this direction, as the introduction of plague into a country may lead not only to loss of human life, but to a state of grave economic importance owing to strict quarantine restrictions being enforced. A scarcity of food helps all other suppressive methods. Care therefore should be taken as to disposal of remnants of lunches in office buildings and of organic waste generally. A great deal can be done ,to keep rats in check by making buildings ratproof.