Animal diseases

Descriptions

Anthrax

Anthrax is a bacterial infection that can be contracted through contact with infected animals or their products. It can also be inhaled, which can be deadly. Anthrax, a highly infectious and fatal disease of cattle, is caused by a relatively large spore-forming rectangular shaped bacterium called Bacillusanthracis. Anthrax causes acute mortality in ruminants. The bacteria produce extremely potent toxins which are responsible for the illeffects, causing a high mortality rate. Signs of the illness usually appear 3 to 7 days after the spores are swallowed or inhaled. Once signs begin in animals, they usually die within two days.

Hoofed animals, such as deer, cattle, goats, and sheep, are the main animals affected by this disease. They usually get the disease by swallowing anthrax spores while grazing on pasture contaminated (made impure) with anthrax spores. Inhaling (breathing in) the spores, which are odourless, colourless, and tasteless, may also cause infection in animals and people.

Black quarter (Black leg)

It is an acute infectious and highly fatal, bacterial disease of cattle. Buffaloes, sheep and goats are also affected. Young cattle between 6-24 months of age, in good body condition are mostly affected. It is soil-borne infection that generally occurs during rainy season. In India, the disease is sporadic (1-2 animal) in nature.

Foot and mouth disease

The foot-and-mouth disease is a highly communicable disease affecting cloven-footed animals. It is characterized by fever, formation of vesicles and blisters in the mouth, udder, teats and on the skin between the toes and above the hoofs. Animals recovered from the disease present a characteristically rough coat and deformation of the hoof.

In India, the disease is widespread and assumes a position of importance in livestock industry. The disease spreads by direct contact or indirectly through infected water, manure, hay and pastures. It is also conveyed by cattle attendants. It is known to spread through recovered animals, field rats, porcupines and birds.

Rabies (Mad dog disease)

It is a disease of dogs, foxes, wolves, hyenas and in some places, it is a disease of bats which feed on blood.

The disease is passed to other animals or to people if they are bitten by an animal with rabies. The germs which cause rabies live in the saliva of the sick (rabid) animal. This is a killer disease but not every dog which bites is infected with rabies.

When the rabid animal bites another animal or human, the germs which live in its saliva pass into the body through the wound caused by the bite. The germs travel along the nerves to the brain. The time between the bite and the first appearance of signs that the bitten animal or human has been infected can take from 2 to 10 weeks or more. The time taken depends on the distance of the bite from the brain. If the bite is on the face or head, the bitten animal or human will quickly show signs, but if the bite is on the leg it will take much longer for signs to develop.

Blue tongue

Blue tongue, a disease which is transmitted by midges, infects domestic and wild ruminants and also camelids, however sheep are particularly badly affected. Cattle, although infected more frequently than sheep, do not always show signs of disease. Virus spreads between animals occurs via the midges of Cullicoides species.

The likelihood of mechanical transmission between herds and flocks, or indeed within a herd or flock, by unhygienic practices (the use of contaminated surgical equipment or hypodermic needles) maybe a possibility.

Pox

Sheep-pox is a highly contagious disease. It causes a mortality of 20 to 50 per cent in animals below the age of 6 months, and causes damage to the wool and skin in adults. Of the pock diseases, sheep-pox ranks only second to human small-pox in virulence. The disease is transmissible to in-contact goats but not to other species of animals. It, however, spreads slowly.

Brucellosis of sheep

The mode of entry is by ingestion or via conjunctiva. The aborted foetus, vaginal discharge and milk from infected goats contain a large number or organisms.

Symptoms in infected goats and sheep state of abortion may occur followed by a quiescent period during which a few abortions occur. The aborted animals do no breed. After 2 years or more another abortions to mislikely to occur.

Tetanus

This is an infectious, non-febrile disease of animals and man, and is characterized by spasmodic tetany and hyperaesthesia. This disease is prevalent all over the world.

Infection takes place by contamination of wounds. Deep punctured wounds provide favourable conditions for the spores to germinate, multiply and produce toxin which is subsequently absorbed in the animal body. The micro-organism present in soil and in animal faeces, and is carried into the wound by a penetrating object. The organism present in the  intestine of normal animals, and under some undetermined conditions multiplies rapidly and produces toxin in sufficient quantities to be absorbed and cause the disease.

Listeriosis

The organisms are excreted in the faeces, urine, aborted foetuses, uterine discharge and milk of infected animals. The organisms are sufficiently resistant to remain viable in animal and human faeces, sewage, soil, silage and dust for several weeks and months. The bloodsucking arthropods may spread infection since organisms have been isolated from cattle ticks and tabanid flies. Under natural conditions certain predisposing factors are related to clinical infection.

Campylobactor  abortion (Vibriosis)

Transmission occurs by coitus. The affected bull scarry the organisms in preputial cavity indefinitely. Mature cows and heifers also carry the infection for long periods. Infected semen from an infected bull is the important means of the disease. The organism survives slow temperature used in semen storage.

Plant diseases

Descriptions

Powdery Mildew

Powdery mildew leaves a white dusty coating on leaves, stems and flowers. Caused by a fungus, it affects a number of plants, including lilacs, apples, grapes, cucumbers, peas, phlox, daisies and roses.

Downy Mildew

Downy mildew is caused by fungus-like organisms and affects many ornamentals and edibles, such as impatiens, pansies, columbine, grapevines, lettuce and cole crops such as broccoli and cauliflower. Often occurring during wet weather, downy mildew causes the upper portion of leaves to discolour, while the bottoms develop white or gray mold.

Black Spot

Black spot is a fungal disease commonly found on roses, but also on other flowers and fruits. While it does not kill plants outright, it weakens them and makes them susceptible to other problems. In cool, moist weather, small black spots appear on foliage, which starts to turn yellow and eventually drops off.

Mosaic Virus

There are a number of mosaic viruses, but gardeners are most likely to encounter two: tomato mosaic virus and tobacco mosaic virus. The former infects tomatoes, peppers, potatoes, apples, pears and cherries; the latter infects tomatoes, peppers, cucumbers, lettuce, beets, petunias and, of course, tobacco.

Mosaic virus causes mottled yellow and green leaves that are sometimes curled and distorted. Some plants exhibit yellowing, stunted growth, malformed fruits and reduced yield. Mosaic virus is more common in hot weather.

Damping-Off Disease

Damping-off disease, caused by several soil-borne fungi, is most problematic in wet, humid conditions. It infects seedlings and causes them to collapse and decay. It is often found in greenhouses but can occur outdoors as well.

Fusarium Wilt

Caused by a soil-borne fungus, fusarium wilt affects ornamental and edible plants, including dianthus, beans, tomatoes, peas and asparagus. The disease causes wilted leaves and stunted plants, as well as root rot and sometimes blackened stem rot. It is especially active in hot summer temperatures.

Verticillium Wilt

Verticillium wilt is a fungal disease that affects hundreds of species of trees, shrubs, edibles and ornamentals. Pathogens, which can live in the soil for years, make their way into the plant through the roots, eventually clogging the vascular system and causing branches to wilt suddenly and foliage to turn yellow and fall off prematurely. It can also lead to stunted growth.

Sooty Mold

Sooty mold refers to fungi that grow on the sticky deposits, called honeydew, left by plant-sucking insects. On leaves it is not only unsightly; it impedes photosynthesis and stunts plant growth. Leaves coated with sooty mold also drop off prematurely.

Snow Mold

Snow mold is a fungus that flourishes in the cold, moist conditions found beneath snow. It attacks turf grass. After snow melts, symptoms become visible: light  tan areas of matted grass caused by threads of mold.

Rust

Rust, another fungal disease, is easy to spot because it forms rusty spots on leaves and sometimes stems. The spots eventually progress from reddish-orange to black. There are many types of rust that can attack plants such as hollyhocks, roses, daylilies and tomatoes. Even your lawn is susceptible to grass rust.