Parasites and eliminating them.

There are many things that can cause an animal to get sick. Besides causes like, for example, genetic predisposition and mistakes in diets, parasites can cause a lot of problems. With parasitism there is a host and an unwanted guest. The parasite (unwanted guest) feeds on its host. Parasites exist as clearly visible tiny creatures, or hardly detectable viruses. In this section we refer mainly to the external parasites like fleas, lice and ticks. Internal parasites, like worms, will also be discussed. Especially fleas cause a lot of inconvenience and annoyance. This blood sucking parasites causes an itching sensation and occur on dogs, cats and rodents a lot. They function, among other things, as an intermediate host for among other things, tapeworms. Enough reason to eliminate parasites on your pet!


Fleas are still the most common skin parasite on dogs, cats and rodents. They are even noticed on guinea pigs. Fleas are very lively brown/black insects that jump on their host in order to suck blood.


Contrary to popular belief, they do not live on pets, but in your home! There are still people that think that flea infestations only occur in “not so clean homes”. This is not true, anyone that has dogs, cats or rodents can encounter flea problems. It is not a shame when that happens, it is shameful though not to treat it.

Worldwide there are about 1900 kinds of fleas. In the UK we mainly have two kinds of fleas: cat fleas (Ctenocefalidis felis) and dog fleas (ctenocefalidis canis) . Cat fleas are the most common in the U.K., dogs usually have cat fleas. The human flea has gone extinct a long time ago. Fleas need blood to lay eggs. They suck blood from a dog or cat and after approximately 36 hours, they can start laying the first eggs. When a female flea does this for about 3 weeks, then you can easily calculate how many young fleas there will be in your house in no time at all. Depending on the temperature and humidity, the eggs will hatch in 1-10 days. The larvae that are crawling around then, feed on organic materials they encounter. During this crawling stage, the larvae spins a silken cocoon and pupates. During this stage flea control is very difficult, since the pupa is practically insensitive to it. Vibrations can cause the adult flea to emerge from the cocoon within a few days. When there is no movement whatsoever, it can take up to 18 months for the adult flea to emerge! This explains why a flea problem will occur after a holiday. Sometimes a rise in temperature, like heating up the house for the Christmas holidays, is enough to spend the festive season in the company of many fleas. The most effective treatment of fleas is in 2 parts. First of all the flea itself needs to be controlled, second of all, the environment. It is also important to worm your pet, fleas are intermediate hosts to tapeworms.

The life cycle of a flea

To control fleas effectively, it is essential to know something about the flea’s biology. Fleas have four main stages in their life cycle: egg, larva, pupa, and adult.

The egg stage

Flea eggs are white and oval.

flea eggs

They are barely visible to the human eye. The eggs are laid on the pet, they stick to the hairs for a couple of hours, then they fall off the animal into the carpet, bedding, floorboards, and soil. Most eggs can be found not on the animal, but in its surroundings!

There are two factors that influence the growth of the eggs:

- temperature
- humidity

Most ideal circumstances for flea eggs are a temperature of 20-25° C and a humidity of 70%. In these circumstances the eggs can develop into larvae within 48 hours. The eggs can develop into larva within 48 hours in these circumstances. In less favourable circumstances it may take 11 to 12 days.

The larval stage

The flea larva is about 0.5 cm long, looks like a maggot, and has hairy extensions which they use to cling on to pets. Because the flea larva is afraid of the light, it hides in dark places (like floor cracks and crevices).

flea larva

The larva feeds on organic material. Its diet consists mostly of faeces of adult fleas. Especially the dried blood in the adult flea’s faeces is essential for the development of the larva. Larvae are more sensitive to temperature and humidity than the eggs. When humidity is under 50% the larvae will die. There are less fleas during a warm and dry summer, than during a wet and warm summer. The larval stage usually lasts 7 to 15 days, but in less favourable living conditions it can last up to 7 months. In the last stage of this development the larva spins a cocoon and the pupa stage begins.

The pupa stage

The cocoon protects the pupa against influences from outside and forms a barrier against insecticides. In the cocoon the pupa will develop into an adult flea. In favourable circumstances this will take 5 – 7 days, but the pupa can survive for almost 1 year, if circumstances are less favourable. Body warmth from the and vibrations stimulate the flea in emerging from its cocoon. When there is no host, the pupa will not develop into a flea.

The adult flea

The adult flea is flat, the legs are perfect for jumping. The flea will feed on the host’s blood within 24 to 48 hours after it emerged from the cocoon. Adult fleas spend most of their life on the host. They feed on its blood several times a day. A female can only lay eggs after she has fed on blood. A female is fertile for 10 to 14 days. She lays 10 to 20 eggs a day.



Ticks occur mostly on animals that live in a woody or grassy neighbourhood. A tick is a small bloodsucking eight legged spider that can transmit Lyme Disease by regurgitating saliva in its host. A tick that has fed and is filled with blood, looks like a grey broad bean. Do not try to sedate the tick by using alcohol or something like that, it will only cause more harm because it induces the tick to salivate and regurgitate into its host. It is best to use a tick removal tool. Insecticides take a while before they work on spider like creatures. Leave remainders of head and legs, they will fall off eventually with the crust of the wound. Ticks in the environment cannot be controlled. About 15% of ticks is infected with the Borrelia bacteria that causes Lyme Disease. Not all infected persons will develop the disease. In Western Europe, the risk of someone developing Lyme Disease because of a tick bite is estimated at less than 1%. When someone does get sick, it is usually very treatable with antibiotics. In a lot of cases it will get better on its own. If the tick is removed within 24 hours, chances of getting sick are minimal.