Scabies in animals

Itch mites in dogs, cats, rabbits and guinea pigs are briefly mentioned in Appendix A. People, who own a dog or a cat, usually discover the problem at a fairly late point. Scabies in dogs and cats must be controlled because the animals suffer from itching and because the mites can cause pseudo-scabies with the people who come into contact with the pets.

Dogs
Dogs only have one kind of itch mites. British studies have shown that 1% of English dogs suffer from canine scabies (mange). In infected dogs, crusty rashes are found on the edges of ears as well as in the elbow region. You may get an early suspicion of scabies in dogs by if the dog make scratching movements in the air with a hind leg, is a sign of increased irritability where you touched it.

Fox scab
Foxes in the wild are sometimes infected by scabies to such an extent that mites fall off them wherever they go. Therefore, itch mites from infected foxes can infect, for example, dogs. If you use your dog for hunting and to hunt foxes from their burrows, you should treat your dog with a mite-repellent, for example, a pour-on product in the coat before hunting.

Cats
There are two kinds of itch mites, which infect cats. One which is similar to the human itch mite, and a smaller, slightly different itch mite. The smallest of the mites, Notoedres cati, is rare in our parts of the world. However, it is seen from time to time. It can infect dogs. Scabies in cats, Feline Scabies (Notoedric Mange) appear as a scaly, crusty rash on the outer parts of the ears, between the ears and in the face where the skin can be heavily thickened.
Each species of itch mites each have their favorite places on the cats. In cows, the tail heads are popular with the itch mites, and in pigs, mites are almost exclusively found on the inside of the ears.

Diagnosis
The veterinarian will help diagnose the animal. The mites are detected through a microscope. Samples of the suspicious crust are removed with a scalpel or sharp spoon.

Treatment
If you have doubts about the treatment, your veterinarian can help you. The pesticides are available at the pharmacy and you can choose to both diagnose and treat the pet yourself. Please be aware that some pesticides can cause illness in young cats, as well as weak cats. Therefore, be sure to read the instructions carefully before applying the pesticide. Pesticides against scabies in animals also work against lice on the same animals.

Scabies from animals

Physiological types of the human itch mite, Sarcoptes scabiei, are found on a wide variety of mammals, with which we often come into contact.

Pseudo-scabies
Itch mites from animals may, when they given the opportunity, taste the skin of the humans with which the infected animal is in contact. However, they cannot settle in the skin, and consequently pseudo-scabies disappear shortly after the actual host animal has been treated or when contact with the animal stops.

The diagnosis is difficult to make. You might see small crusty papules of the skin – not actual burrows. Itching is the most prominent symptom and is often what makes people seek medical advice. Generally, from the papules’ location on the body, you may suspect that they are caused by contact with an infected animal. The papules’ location is closely linked to the way in which you associate with the animal. Scabies from cows may appear in the back of the neck, shoulders and wrists. This makes sense when you see a farmer attach milking machine to cows. The itch mites easily penetrate fabrics. Dogs or cats in bed allows for papules and itching all over the body. Otherwise, pseudo-scabies from cats and dogs are usually found on the flexible parts of the arms, chest, abdomen, thighs and lower legs. Be aware that fur mites from dogs and cats can cause similar symptoms in humans.

Waiting period
In order to be infected with pseudo-scabies, you must have been in contact with the infected animal for a relatively long period of time – 3 weeks or more. Scabies and pseudo-scabies are of allergic reaction to the mites’ presence in the skin. The first mites that burrow, does not cause any symptoms. They merely activate the immune system. It is not until a few weeks after the infection that the skin will react to new mites with papules and itching. If you have had scabies before – either human scabies or pseudo-scabies – your immune system is already activated and your skin will react more quickly to the pseudo-scabies.

Animals that bite, sting and irritate

Parasitism is very common in the animal kingdom. It has been estimated that about a quarter of the existing animal species live in or on the remaining three-quarters.

The words bite and sting are often used indiscriminately, but it is best to say that an animal bites when it uses its mouth, even when this is modified to form a sucking proboscis, and that it stings with a special organ, the sting, which is normally situated at the rear end.

When one animal bites another, it does so to obtain food, either by sucking blood as a mosquito does, or by killing the prey and consuming the contents of its body, as is done by the predacious fly bug Reduvius personatus among others. On the other hand, animals with a sting use this as a weapon, either for attack or defence, as for example in the hornet.

For an animal that sucks blood it is normally in its own interest that it should do so with as little disturbance as possible. The sucking proboscis is normally a delicate structure consisting of two tubes, one very thin down which saliva passes and the other a little larger through which the blood mixed with saliva is sucked up. The saliva may contain substances which prevent the blood coagulating and it may also contain substances that act as a local anaesthetic. The inflammation and itching that follow a bite are probably due to the foreign proteins in the saliva introduced by the biting animal. Humans react very differently to bites, some swelling to an alarming extent, while others scarcely react at all.

The position is very different in animals that sting their prey or sting in self-defence. Here the victim is usually paralysed or rendered incapable of resistance. In such cases the sting• usually has associated glands which produce a venom, that is, a substance which even in very small amounts can kill or paralyse other animals or cause them pain.

In view of the fact that people react so differently to bites and stings it is almost impossible to identify immediately the causative organism. There is also a possibility that bites may be confused with pimples or other reactions due to hyper- sensitivity. In many cases, it is possible that other factors may help to identify the cause, as for example the position of the bite. It is also as well to note the time of the attack, whether domestic animals might be involved, and whether there have been other opportunities for parasites to enter the house.

Pests in House and Home

pests-in-house-and-home-bookcover480In writing this book the aim has been to produce a practical handbook which gives a comprehensive account of the animals which can be met indoors in Europe, with particular attention to the tracks and signs they leave and the damage they sometimes do. The use of this book does not require any previous knowledge of zoology, and the identifications are based entirely on characteristics which can be seen with the naked eye or with an ordinary good lens.

The book has been written not only for the private house owner, but should be equally useful to all those who in their daily life have to deal with problems involving harmful animals in houses, shops, stores and factories. Far from all animals encountered indoors are harmful, so the book should also appeal to all those who have a general interest in biology.

The book was originally planned in collaboration with Preben Dahlstrom who before he died had produced the keys on pages 12-1 7 and the colour plates on pages 18 and 19.
The book’s photographer and its two authors are associated with the Danish State Pest Laboratory, and they are much indebted to Hans Wickmand, its Director from 1948 to 1975.

Animal names and systematics

In using a book of this type it is essential to understand the method of naming animals. The scientific study known as systematics is concerned with naming animals and plants, and with arranging them in groups which indicate their relationships with one another.

Modern systematics is based on the work of the Swedish naturalist Carl von Linne (1707-1778), also known as Linnaeus. He gave all the then known plants and animals a Latin name and arranged them in groups according to their physical appearance. He chose Latin because at that time this was the international language of science.

The principles of nomenclature established by Linnaeus are still in use today. The Latin or scientific name of an animal or plant consists of two parts, the first denoting the genus (plural genera), the second the species. In the present book it is necessary to use the scientific names because many of the animals mentioned do not have common English names, and when these do exist they are often not standard throughout the country. For example, the song thrush is known in Scotland as a mavis.

In 1859 a book was published which has had a profound effect on man’s understanding of the world around him.

This was The Origin of Species, by the English scientist Charles Darwin (1809-1882), who put forward the theory of natural selection, which seeks to explain how all existing species have evolved from species which have existed in past ages. Since Darwin’s time systematics has become more than a means of naming animals and plants; it has in many cases shown their relationships by grouping together those which are thought to have evolved from a common ancestor. The animal kingdom has been divided into some 14 major groups, known as phyla (singular phylum). Only a few of these have representatives occurring indoors, namely worms, molluscs, arthropods and vertebrates. The worms are represented in houses only by earthworms. The molluscs, a group that includes snails and bivalves, are not normally found in houses, except for certain slugs that occur in cellars.

The vertebrates or animals with a vertebral column include fishes, amphibians, reptiles, birds and mammals, including of course man.

Arthropods are animals with jointed legs. The group contains the crustaceans, scorpions, millipedes, centipedes, mites, spiders and last but not least the insects. About one million animal species have been described and more than three- quarters of these are arthropods. It is not surprising, therefore, that most of the animals found in houses belong among the arthropods.

Houses as animals habitats

In addition to a favourable climate, an animal must have the right food and plenty of places to hide or shelter in if it is to thrive.

The average house certainly has plenty of hiding-places, but it does not always fulfil the other requirements. It would be wrong to suppose that the comfortable warmth of our houses throughout the year would be ideal for many invertebrates, for this is far from being the case.

The climate in our houses is very different from the summer climate outdoors in temperate latitudes. Room temperatures may be about the same as on a warm summer’s day, but the air is sometimes bone-dry, giving a desert-like climate. This is something that we our- selves may sometimes find uncomfortable, but for most invertebrates it can be catastrophic.

As a result, very few of the animals found indoors are also found outdoors. This, of course, does not apply to the many small invertebrate animals such as moths which come in through windows and doors at night, being attracted by the light. These soon die unless they can find their way out.

Most of the ‘house animals’ come originally from other parts of the world. Curiously enough, only a few of them are found living in the wild, and so it is not always possible to say exactly where they originate from, but most of them probably originated in tropical or subtropical regions. Animals with such specialized habits have probably never been numerous in the wild, and may have only become successful on entering a man-made habitat. Some of the species concerned have been associated with human habitations for thousands of years, and during this long period of time, which for insects would involve thousands of generations, they have had plenty of opportunity to evolve new types, with habits and forms that differ considerably from the original ancestral forms.

The insect and other invertebrate pests that live indoors must not therefore be regarded as casual visitors, but rather as highly specialized residents. They are relatively free from competitors and predators, and they usually have a plentiful supply of suitable food.

Introduction

If one looks back on the history of man which, so far as it is known has covered a period of perhaps a million years, it will be apparent that for some 99 per cent of this time he has been a hunter and gatherer of food. That is, he has collected edible fruits and vegetation, larvae and other small invertebrate animals. At an early period in his history, man also learned to hunt larger animals with increasingly improved weapons and methods. The provision of food for the family or group depended upon what the surrounding countryside had to offer, and there was no knowledge on how to store foods in any quantity.

True pests of stored goods were therefore unknown to these ancestors, who must however have had problems with blowfly maggots infesting their game and other pests destroying their hides and skins.

Nor would they have been spared by the true parasites. Lice must have infested their hair and bed bugs and fleas must have multiplied, generation after generation, over thousands of years. Sleep must have been disturbed by mosquitoes, with their ceaseless buzzing, and also by the numerous small invertebrates which lived in their dwellings. These would include swarms of flies and other insects which would be attracted by domestic waste.

About 10,000 years ago came a significant change. Man began to plant and harvest crops and to keep domestic animals. This new life form brought many advantages, for it provided a more secure existence and the soil could feed far more people when it was used this way. But it also brought problems. Animals which had hitherto fed on scattered wild grass seeds now had the opportunity, when their food plants were sown in whole fields, to multiply as never before. Food specialists among the invertebrates, which had previously survived winters with stores they collected during summer and autumn, could now enter and exploit the enormous food stores collected by man.

As man started to establish permanent dwellings, these provided excellent living quarters for many animal species, whether in the house itself or in the outhouses used by the domestic animals. There was also woodwork to gnaw and textiles and furs to eat.

The buildings provided new hunting grounds for animals such as spiders, and also places for nesting and spending the winter for many animals which had previously used hollow trees and rock crevices. Throughout the ages these man-made facilities increased, and even today, with all our technical aids, we are far from being alone in our houses and stores.