Introduction

Of the ticks found in the south-eastern United States, the brown dog and American dog ticks are the most troublesome. The brown dog tick rarely bites humans, but infestations are frequently found on dogs and in the home. The American dog tick attacks a wide variety of hosts, including humans, but rarely infests homes.

The Brown Dog Tick

The brown dog tick seldom attacks animals other than dogs. It is most likely found where dogs are kept in or around the house. The brown dog tick is not known to transmit diseases to humans but may transmit disease among dogs.

The adult female tick lays a mass of 1000 to 3000 eggs after engorging on a dog's blood. These eggs are often found in cracks on the roof of kennels or high on the walls or ceilings of buildings. In the house, eggs are laid around baseboards, window and door casings, curtains, furniture and edges of rugs. The egg-laying females are often seen going up walls to lay eggs.

The eggs hatch in 19 to 60 days into a six-legged, small seed tick. The seed tick takes a blood meal from dogs when they are available. The larvae are so small they won't be noticed on the dog unless a number are together. The seed tick remains attached for three to six days, turns bluish in color, and then drops to the floor. After dropping from the host, the seed tick hides for six to 23 days before molting into an eight-legged, reddish-brown nymph. It is now ready for another blood meal and again seeks a dog host.

The American Dog Tick

The American dog tick is also a common pest of pets and humans. The adult males and females are frequently encountered by sportsmen and people who work outdoors. Dogs are the preferred host, although the American dog tick will feed on other warmblooded animals. The nymphal stages of the American dog tick usually only attack rodents. For this reason the American dog tick is not considered a household pest.

The female dog tick lays 4000 to 6500 eggs and then dies. The eggs hatch into seed ticks in 36 to 57 days. The unfed larvae crawl in search of a host and can live 540 days without food. When they find a small rodent, the larvae attach and feed for approximately five days. The larvae then drop off the host and molt to the nymphal stage. The nymphs crawl in search of a rodent host, attach to a suitable host, and engorge with blood in three to 11 days. Nymphs can live without food for up to 584 days.

Adults crawl in search of dogs or large animals for a blood meal. Adults can live for up to two years without food. American dog tick adults and many other species can be found along roads, paths, and trails, on grass, and on other low vegetation in a "waiting position." As an animal passes by, the tick will grasp it firmly and soon start feeding. The males remain on the host for an indefinite period of time alternately feeding and mating. The females feed, mate, become engorged, and then drop off to lay their eggs.

The American dog tick requires from three months to three years to complete a life cycle. It is typically an outdoor tick and is dependent on climatic and environmental conditions for its eggs to hatch.

Effects of Ticks

When feeding, ticks make a small hole in the skin, attach themselves with a modification of one of the mouthparts which has teeth that curve backwards, and insert barbed piercing mouthparts to remove blood.

The presence of ticks is annoying to dogs and humans. Heavy continuous infestations on dogs cause irritation and loss of vitality. Pulling ticks off the host may leave a running wound which may become infected because of the ticks type of attachment.

The brown dog tick is not a vector of human disease, but is capable of transmitting canine piroplasmosis among dogs.

The American dog tick may carry Rocky Mountain spotted fever, tularemia and other diseases from animals to people. Dogs are not affected by these diseases, but people have become infected by picking ticks from dogs. People living in areas where these wood ticks occur should inspect themselves several times a day. Early removal is important since disease organisms are not transferred until the tick has fed for several hours.

The American dog tick is also known to cause paralysis in dogs and children where ticks attach at the base of the skull or along the spinal column. Paralysis is caused by a toxic secretion produced by the feeding tick. When the tick is removed, recovery is rapid, usually within eight hours. Sensitized animals may become paralyzed by tick attachment anywhere on the body.

Lyme disease is transmitted by ticks. Most transmission occurs in the New England states and the primary vector is the blacklegged or deer tick. This tick is believed responsible for most cases of lyme disease in the northeastern and north central United States. The deer tick is not prevalent in Florida, but species that are close relatives and are capable of transmitting Lyme disease are common throughout the state. The American dog tick and the brown dog tick are not considered important vectors of Lyme disease. In cases of tick bites where Lyme disease is suspected, a physician should be contacted so that appropriate blood tests can be done.

Control

Ticks should be removed carefully and slowly from pets and humans as soon as they are noticed. If the attached tick is broken, the mouthparts left in the skin may transmit disease or cause secondary infection. Ticks may easily be removed by touching the tick with a hot needle or alcohol to relax it. Then grasp the tick firmly with tweezers or fingers near the mouthparts and pull evenly and firmly. A small amount of flesh should be seen attached to the mouthparts after the tick is removed.

Pesticidal control of ticks may require treatment of both the pet and the infested area. If a heavy tick infestation occurs it is necessary to treat pets, home and yard at the same time.

Pets should be treated by using dusts, dip or sprays. Rub dusts into the fur to the skin being careful not to allow chemicals to get into the eyes, nose or mouth. Heavy tick infestations on the animal should be controlled by spraying or dipping.

Premise sprays are registered for tick control. Read the label thoroughly to be certain that the site of application (lawn, house, crawl space, kennels, etc.) is on the label.

Brown dog tick infestations of homes and yards are frequently difficult to control. Insecticides should be applied inside the house carefully as light spot treatments to areas where ticks are known to be hiding. Special effort should be given in treating areas frequented by pets. Applications at two to four week intervals may be necessary to eliminate the ticks. Pets should be kept off treated surfaces until the latter are dry.

People entering tick infested areas should keep clothing buttoned, shirts inside trousers, and trousers inside boots. Do not sit on the ground or on logs in bushy areas. Keep brush cleared or burned along frequently traveled areas. Repellents will protect exposed skin. However, ticks will crawl over treated skin to untreated parts of the body.