They're small, silent and dangerous. But they're here, and they're not going away.

One of the area's most insidious menaces, deer ticks (also known as black-legged ticks) are a vector for Lyme disease, a debilitating condition that can cause joint and muscle aches and pains, cartilage breakdown, arthritis, and even Alzheimer's-like symptoms of cognitive failure.

Entomologist Dave Simser of the Cape Cod Extension Service visited the Wareham Free Library on Thursday to speak about the prevention of tick-borne illnesses and what people can do about ticks and their control.

He said that if you took "one thing away from the talk," you had to remember that deer ticks are most dangerous in their nymph form, which occurs from May to July, when they are difficult to detect because they are only about the size of a poppy seed. (Adult ticks, he said, are about the size of a sesame seed).

Other interesting and helpful bits of information:

• Lyme disease is the most well-known disease transmitted by ticks, but deer ticks (Ixodes scapularis) also transmit babesiosis, or "Nantucket fever," and anaplasmosis, a blood-borne bacteria.  Dog ticks (Dermacentor variabilis) transmit tularemia and Rocky Mountain spotted fever.
• The tick life cycle involves three stages when they feed on blood: larvae, nymph and adult.  In general, larvae and nymphs feed on smaller animals, specifically mice, where they acquire the Lyme disease bacterium.  When they become nymphs and adults, they bite larger animals like deer and humans transmitting Lyme disease.
• Humans are not the only animals that suffer from Lyme disease.  Dogs, cattle, and horses also can suffer from the disease, but all exhibit different symptoms.  Cats, however, do not appear to be affected by the disease.
• Ticks must feed for 48 hours before they can transmit Lyme disease.
• The most easily identifiable symptom of Lyme disease is an expanding, bulls-eye rash.  Forty percent of sufferers, however, never exhibit this symptom.
• Tick "spit" includes 400 different chemicals that include anticoagulants to keep the wound from closing up.  Biochemists are examining some of these chemicals for use in open-heart surgery.
• Chronic Lyme disease is not currently recognized as a disease by many insurance companies.
• Ticks are active at temperatures above 35 degrees Fahrenheit so, yes, you could get Lyme disease in the winter.
• If you are bitten by a tick and are concerned that it may have Lyme disease, you can send it to be tested at the Cape Cod Cooperative Extension or the Barnstable County Department of Health and the Environment.
• Simser also recommended circling the date you find the tick so that, if it turns out you have the disease, a doctor can pinpoint the time of infection.