Internal And External Parasites In Cats: How To Deal With It

Knowing the problems and facts about parasites is the first step in prevention. Routine care of any cat or kitten should include verifying that the fur and skin are kept free of all parasites.

There are two types of parasites:
External parasites
Internal parasites
External parasites in cats: fleas, ticks, lice, mites, ringworm, maggots, bronchitis, etc
Internal parasites in cats: Worms such as roundworms, tapeworms, and toxoplasmosis, etc

A parasite is an animal or plant that takes food and protection from a host animal or plant. It survives to the detriment of its host, causing loss of condition and sometimes death. In some cases, such as ringworm, the parasitic condition of a host cat can be transmitted to the humans with whom it lives.

Preparations for eradicating external and internal parasites are easily available. Ask for veterinary advice, follow instructions carefully, and follow a strict cleaning regime, and parasites should not be a problem.

External Parasites


The cat with fleas can scratch obsessively, particularly around the neck, and can groom the base of the spine vigorously and spontaneously. You can also worry about the entire length of the spine. Using the tips of the fingers and nails, groom the cat behind the ears, the neck, the spine and the base of the tail. If this reveals dark, chocolate brown grit, place them on damp tissue. If red leaches from them, they are flea droppings, which are mainly composed of dried blood.

In severe infestations or where the cat is really allergic to the substances produced by the flea in its bite, skin patches with scabs can be found with the scabs that come off to reveal slightly watery and sore-looking patches. This is cleared up quickly with the eradication of fleas.

Fleas move very fast through the cat’s fur and are difficult to catch even if they are seen. A cat can be attacked by the cat flea, the dog flea, and the Luman flea. They all put their eggs in the cat’s fur; many will come out and hatch in larvae in cracks in the floorboards, in the weave of fabrics and in the carpets.

The larvae become fleas that feed immediately on any host that can wander by. A flea can live, with periods of feeding and resting, for up to two years, but the norm is two to six months.

Many antiparasitic preparations, including powders, shampoos, and aerosols, are available at pet stores, supermarkets, and veterinary practices. With strong infestations, both the cat and the environment must be treated.

Long-acting aerosols are probably the most effective for the environment. For the cat, one of the easiest and most effective methods is an insecticide that is applied in a small area on the cat’s neck. This punctual application provides protection to the whole body for a month.

Modern parasiticides are very safe and there are some available that can be applied to very young kittens. Your veterinarian will advise you on the most appropriate products for young cats.


Ticks, like fleas, are bloodsuckers. However, unlike fleas, they live permanently on the cat. This parasite is normally of rural distribution, but the hedgehog tick is common in urban areas. The tick digs its head into the skin of the host animal and crammed with blood. Sometimes it can reach the size of a bean, then it is dropped to complete its life cycle without harming the cat further. However, it could happen to other animals in the home.

Tick ​​removal requires precision, to prevent the parts of the head from being buried in the skin. The cat itself may be irritated by the tick burrow and knock it out, leaving its head behind. This usually establishes a chronic infection followed by an abscess or a sore that is difficult to cure.

A veterinarian can use substances to relax the grip of the tick before removing it. A home equivalent is a surgical alcohol (or any form of alcoholic spirit). All ticks are carefully removed with tweezers or a custom-made tick remover (available at pet stores).

Tick ​​bites may be responsible for a bacterial disease called Lyme disease. This occurs in Britain, but it is more widespread in the United States. Symptoms include a reluctance to jump followed by acute and recurrent lameness, elevated temperature, lethargy, and swollen lymph nodes, particularly around the head and limbs.

Blood tests confirm the cause, and treatment is a course of antibiotics for four to six weeks. Lyme disease should not occur if ticks are avoided. Most flea preparations also prevent tick infestation.


Fortunately, a lice infestation is uncommon in cats, but poor conditions and age extremes make people susceptible. There are three types of lice that are known to occur in cats, one that sucks blood and two that bite.

The telltale signs are some scratches, usually not very excessive, combined with dry skin that shows an unusual increase in dandruff or scurf. Head lice can be seen quite easily with the naked eye.

The eggs, or nits, are laid directly in the lower third of the hair and appear to be stuck in place. Flea preparations are effective.


Four groups of mites affect the cat’s skin and ears. The mite harvest appears in autumn (fall). The cat is affected by the larvae that tend to settle in areas where the fur is thin, such as between the toes, in the lower part of the belly, in the groin and around the lips and nose.

Orange larvae are almost visible to the naked eye. They establish irritation in which the cat attacks vigorously with teeth and claws, thus creating more irritation.

The sores that develop are round, moist and surrounded by the skin with scabs. Mite infestation is highly contagious and is treated with insecticidal preparations.

The ear mite is commonly transmitted from one cat to another. The irritation is sometimes severe; the cat shakes its head, holds its ears almost flat and scratches furiously. This often leads to secondary infections that arise from self-inflicted trauma. The evidence of ear mites is a dark brown tarred substance in the ears. Due to the delicacy of the ear, it is advisable to ask your veterinarian to perform the initial treatment. The owner can clean the ear gently.

Cheyletiella mites cause a condition known as “walking dandruff,” and are less common. However, they often seem to cause little irritation to the cat though there may be more scratching and grooming than usual. Excessive dandruff is the usual sign. The mite normally lives in the wild rabbit and can also affect people (rashes appear on the chest, stomach, and arms).

The treatment is with parasiticides, both for cats and humans!

Fortunately, a rare form of scabies is caused by an excavator mite. It is usually found around the head starting at the base of the ear. There are severe irritation, hair loss and general lack of condition.

Blood poisoning can occur in severe cases. Antibiotic treatment is necessary for any secondary infection, while actual skin damage is treated with the use of parasiticidal preparations.


Ringworm is caused by a fungus and can affect humans, especially children. The name comes from the shape of the lesions that are seen on the skin of humans, which are circular, red, scaly and very itchy. In the cat, particularly the Persian, often all you see are small pimples and dandruff on the skin. (However, these cats can be very contagious.) In the worst case, wet and pink sores extend outward. The fungal parasite lives in the hair and not in the skin, and causes the hair to break off.

Ringworm can affect animals that are not in the best condition, or that are young, and can be a major problem in long-haired cats.

The diagnosis is initially made by using specially filtered light (Wood’s Light) when about 65% of cases will fluoresce. Laboratory tests are more reliable but take longer. The eradication process is long and tedious. Animals are treated with fungicides, both in the form of baths and in external applications and also tablets.

The entire environment, human and animal, must be carefully cleaned to eradicate all spores. There is no simple answer to the problem. Professional advice on the procedure should be taken and, if necessary, the local environmental health department consulted.

In the United States and in the United Kingdom, research is aimed at improving diagnostic tests as well as treatments. Considerable headway has been made in the production of a vaccine, but at present only cuts down treatment time.


Flies may be attracted to animals by the presence of discharge from wounds, or diarrhea, and lay their eggs in the fur. Flystrike, as this situation is known, is particularly common in cats in poor condition, such as those in feral colonies. The maggots burrow into the skin and form tunnels that can run for considerable distances.

Toxins produced to aid burrowing are absorbed by the cat and cause toxemia (blood poisoning). If you find maggot infestation on your cat, clean it as thoroughly as possible using soap and water and contact the vet without delay.


Infectious bronchitis is sometimes caused by parasitic bacteria that lodges in the respiratory tract of animals. The parasite itself usually does not cause disease, but certain strains of the parasite cause bronchitis. In a dog, this may appear as kennel cough.

A cat, on the other hand, can cough and sneeze, with or without a nose and eyes. Normally, the disease is self-limiting. However, in very young or elderly cats, or in those with other debilitating diseases, it can be persistent and problematic to eliminate it. The organism is sensitive to several antibiotics.

Internal Parasites

The cat is affected by two groups of internal, parasitic worms: roundworm and tapeworms. Effective treatments against worms are available, without a prescription, at pet stores and supermarkets. However, experience has shown that these can be difficult to administer with total precision.

Routine deworming treatments, and advice, are best obtained from your veterinarian. Antiparasitic preparations that provide multiple protection to the cat are now available in tablets or injections. Regular and well-spaced treatments will keep your cat free of worms. These are often given at the same time as the annual booster vaccine but may need to be given every six months.

Roundworms (Infestation)

Roundworms include ascarids, hookworms, and lungworms. Infestations are difficult to detect unless the attack is severe, in which case, especially with ascarids, a ball of live worms can be annulled. If you suspect an infestation, you will probably need to take a stool sample to the veterinarian for accurate identification.

Ascarids and hookworms live in the small intestine. They have very similar life cycles but whereas ascarids float freely and feed on food in the digestion process, hookworms adhere to the lining of the intestine and suck blood.

The symptoms are, therefore, slightly different. In a severe ascarid infestation, the cat will have diarrhea, the fur will be thin and the cat will usually look uncomfortable. Often the belly is distended (“pot-belly”).

The main symptom of hookworm infestation is anemia, which is a cat that is more obvious in the skin of the nose and gums. The gums appear excessively pale, almost white. There is a general lack of energy and the cat can become very thin.

The intermediate host of the lungworm is the slug or snail, which a cat could eat. However, birds or rodents are more likely to eat them first and infectious larvae reach the cat when they eat them.

However, an infestation is quite rare. After a complicated journey through the intestine and lymph nodes of the cat, the larvae become adult worms, which eventually enter the lungs through the bloodstream. As a result, respiratory symptoms, similar to bronchitis or pneumonia, occur.


The diagnosis of tapeworm is relatively easy. Segments of tapeworm containing eggs are shed and adhere to the fur around the anus. They look like grains of rice.

Tapeworms require intermediate hosts and the flea fulfills this function in relation to the most common tapeworm that affects the cat. Flea control is therefore important. Flea larvae eat the secreted tapeworm segments that contain the eggs. The infectious stage of tapeworm is reached when the adult flea feeds on the cat to eat blood. If the cat catches and swallows the flea, as it may do while grooming, the process is completed.

The infectious stage of the second most common tapeworm that affects cats develops in the livers of small rodents. Infected livers and other intestinal parts will surely be consumed by a cat if it catches one of these animals.

The way to prevent tapeworm infestation is to eradicate fleas and discourage your cat from hunting. Both may be impossible goals, but although tapeworms remain a problem, their presence does not seem to affect cats far beyond diarrhea in the case of a very intense infestation.


Toxoplasmosis is caused by microscopic organisms called coccidia. Organisms can infect humans, although the symptoms of the disease are rarely felt. However, if a pregnant woman is infected, the fetus may be affected, resulting in a miscarriage or brain damage in the baby.

The disease cannot even affect the cat in any recognizable way, although it can cause a chest infection in young cats. In older cats, there can be a great loss of condition, digestive disorders, and anemia. Eye problems are not uncommon.

The immature egg of the parasite is passed in the cat’s feces so that the potential contact with any fecal matter when changing and cleaning the sand trays (pans) must be counteracted by a rigid hygiene routine. Oocysts passed by the cat with toxoplasmosis takes at least 24 hours to become infectious, so the litter trays should be changed as soon as possible after use and wear rubber gloves.

Young children should stay away from the litter trays at all times. You should also frequently clean the feces of neighborhood cats that visit your garden and use it as a toileting area.