Tapeworms

Tapeworms

These are complex animal parasites that have a life cycle requiring at least two 'hosts', to survive. The primary or intermediate host carries the 'larval' form, often living in the most inner most tissues of this host. In most cases, this primary host, is eaten by the secondary or final host, with the tapeworm developing to an adult in the intestine of this final host. Because dogs are carnivores and by nature are creatures that will tend to eat others, they are invariably the final host. Many speciess are species specific; i.e. they will form an adult in a specific species (perhaps the dog and not the cat).

Principal Northern European Species

The principal species affecting acts and dogs in northern Europe can be divided into three groups.

1. Dipylidium caninum

This is the most common tapeworm of cats and dogs. The adult lives in the small intestines of the cat or dog and sheds segments which are usually 5-8mm long (this is actually the width of the parasite when the segment is attached to the adult) when passed out in the faeces. The segments are often shed inside your home where the eggs are released. These are eaten by flea larvae which crawl around in the pile of the carpet and in cracks and crannies in flooring and skirting boards. The flea larvae acts as the intermediate host and will develop into an adult flea in due course. When the flea jumps onto your dog and sucks blood sometimes it can be eaten by the dog and allow the larval stage to complete it's development into an adult worm. The life cycle of Dipylidium is only 3 weeks.

Dipylidium life cycle

The key to success in eradicating this Dipylidium from your pet is to understand the life cycle and to understand that you have to eliminate the flea to eliminate the worm. See Parasitic Skin Conditions.

Taenia species

There are a large number of Taenia species, of which a few affect dogs and cats. They have different intermediate and final hosts in many cases and it depends totally on your pet’s life style whether he or she will contact these worms. If you have a sedentary house dog then it is unlikely, if you have an outdoor rabbiter then it is quite likely. The life cycle varies depending on the species of Taenia from 2 to 10 weeks. The segments vary in size depending on species but are often a cm in length.

Name	Final host	Intermediate host
Taenia ovis	Dog	Sheep
Taenia multiceps	Dog	Sheep
Taenia serialis	Dog	Rabbit
Taenia hydatigena	Dog	Sheep, ox, pig
Taenia pisiformis	Dog /Cat	Rabbit
Taenia taeniaeformis	Cat	Mouse / Rat.

Echinococcus species

This group are a threat to human health; i.e. they are a zoonosis. For this reason owners of cats and dogs should be aware of them and should worm regularly as man can act as the intermediate host for this group. They are particularly prevalent in sheep rearing areas where dogs may have access to infected dead sheep carcasses. If you live in a rural area. In, particular, we would recommend very regular worming against this parasite They have a life cycle of between 4 and 6 weeks and are so small in their adult form in the dog that you are unlikely to spot them. If your pets eat carrion, hunt or receive raw meat, de-worm them regularly. The final host can be almost any type of dog, cat and wild canid and the intermediate host is man, herbivores (sheep, ox, deer), pig and man. In the intermediate host Echinococcus forms hydatid cysts, often in the liver and lungs. This can lead to organ failure and death. In Great Britain the problem is restricted and caused by Echinococcus Granulosa. Elsewhere in Northern Europe the problem is more widespread and caused by another species, Echinococcus Multiocularis which is a very serious zooanosis in man.

Symptoms of infection

Most tapeworms live in the small intestine of the final host, the dog. Heavy infestations in this area may cause diarrhoea, occasionally vomiting when large sections may be vomited, unthriftiness and weight loss. More commonly low infestations will cause anal irritation with the dog licking and chewing around the anal area or scooting (dragging hind quarters along the ground). This is due to expulsion of the worm segments which due to their sticky nature often attach to the skin and hair around the anal region. When they first emerge they have a pearlescent white colour and contract along their length looking at times like a miniature dumb-bell. The contractions of the segment are highly irritating to the dog. After a while they dry and shrivel. A lot of people compare them with a grain of rice which changes from white to yellow with time.

Treatment

We believe that Droncit is probably the most broad spectrum product on the market and is recognised by the British Government as sufficiently efficacious to be used in the ‘Pet Travel Scheme’ and for Quarantine. Lopatol is also very efficacious although it doesn’t have the benefits against Echinococcus.

Frequency of worming

This again depends on the dog's lifestyle and where you live. A rural, dog in sheep country may need to be wormed every month. We would recommend twice yearly worming as a minimum with worming every three months in any pet which regularly hunts or scavenges.