Plea from farmers.

If your dogs run - and poo - in sheep country then pleeeeeassse worm them for tapeworm every
three months. Sheep pick up the tapeworms from dog poo and whilst it is rare that it causes symptoms, cysts can and do arise in the sheep's tissues, some of which can cause health problems and some of which would result in deductions when the carcase is processed. Even when there is no deduction and hence financial penalty to the farmer, none of us like to find that some of that lamb we nurtured and reared has had to be incinerated because of a tenuicious cyst.
In 2009, cysts caused by tapeworms originating in dogs cost the British industry an estimated £7.5million. An estimated 9% of lamb's livers were condemned, accounting for £0.5million of that total.
(Source: Eblex Lamb Briefing 10/07 12th July 2010.)Unequivocally, dogs which are Drontalled only every six months do emit viable tapeworm that can infect sheep.
Re: ticks, if you are in a Lyme Disease area, prevention is better than hoping to see and remove safely any tick that bites your dog. The spirochaete that causes the disease is in the tick's saliva and vomit; unless you are very skilled and always lucky, the tick can regurgitate as you remove it, and the spirochaete is then even more likely to enter the dog's system than if you left the tick alone. It's a horrible disease, hard to diagnose in a human and moreso in a dog, very hard to treat even if diagnosed, and all those of us with arthritic dogs, think on... could that arthritis be a result of a long-ago tick bite...?