Insects that cause nuisance or harm to your dog by biting, stinging, or spreading disease can be divided into two groups, those that seek for a blood meal and those that bite or sting as a defensive mechanism. The former group includes fleas, ticks, mosquitoes and flies; the latter includes wasps, bees, spiders, ants and centipedes.
With eight legs instead of six, the tick is cousin to the spider, not the insect. Ticks are blood-sucking parasites that attach themselves to animals and people. Once attached to a host, ticks feed voraciously. As they feed, ticks can transmit a large number of diseases, including Rocky Mountain spotted fever, encephalitis, tularemia, Q fever, and Lyme disease. The latter shows a frightening collection of symptoms that can mimic fatigue, heart problems, and arthritis and cause birth defects, affects dogs and horses as well as people. Lyme Disease is tough to diagnose but can be treated with antibiotics.
Ticks also release toxins that can harm their hosts. Skin wounds caused by ticks can lead to secondary bacterial infections and screwworm infestations. Severe tick infestations can lead to anemia and death.
Ticks can be found worldwide. There are three families of ticks, one of which Nuttalliellidae comprises a single species, Nuttalliella namaqua. The remaining two families contain the hard ticks (Ixodidae) and the soft ticks (Argasidae). Although they share certain basic properties, argasids and ixodids differ in many structural, behavioral, physiological, feeding, and reproductive patterns.
Some ticks prey on specific animals, though other species can prey on many species of animals, including humans. Also blood-sucking behavior is different depending on the species. In temperate climates adult feeding activity is primarily in late summer and early fall but may begin later after a dry summer. Larvae and nymphs are active from spring through fall. Ticks can survive from several months to several years without food if environmental conditions permit.
Most species of ticks have a favored feeding area on a host, although in dense infestations, ticks may attach themselves wherever they can find a feeding location. Some ticks feed chiefly on the head, neck, shoulders, and pubic area. In other species, the favored sites may be ears, near the anus and under the tail, or in nasal passages.
Unlike the flea, the tick is a sluggish mover and can easily be picked off the dog as it crawls about looking for a feeding spot. Look for feeding ticks around the dog’s head and ears and in his armpits and the inside of his thighs. If you miss one as it crawls, you’ll likely find it when it bolts on to feed as the inflated body is hard to miss in a hands-on inspection. Ticks that have been on an animal only for a short time (an hour to a few days) appear flat. Ticks that have been on an animal for days appear much more rounded due to the blood they have consumed. When fully engorged, they drop off.
Ticks should be removed from your dog as soon as possible to minimize disease and damage. Use tweezers or protect your fingers from the tick’s body fluids with surgical gloves or a plastic bag (as some tick-borne diseases e.g. Rocky Mountain spotted fever can be immediately transmitted through breaks in your skin or contact with mucous membranes), grasp the tick firmly, rock it back and forth a few times, and pull it out. If a small piece of skin comes along, it’s unlikely that any of the tick’s head has been left behind. A small amount of antiseptic cream on the spot where the tick was removed will help prevent local infection, especially on tender ears, a favorite feeding place for ticks.
If your dog is severely infested with ticks, you should promptly take it to a veterinarian for tick removal. Heavy infestations will not only severely damage the skin, but the chances of anemia, paralysis, and other complications are high. Your veterinarian is in the best position to provide a heavily infested pet with the care it needs.
Fleas are small wingless insects that feed on animal blood. In addition to being a nuisance, they can also transmit diseases and cause allergies or anemia. Two common species of flea are the cat flea (Ctenocephalides felis) and the dog flea (Ctenocephalides canis). However, most of the fleas found on both dogs and cats are cat fleas.
Pulex irritans, considered a flea of man, also feeds on dogs and cats. Fleas require warmth and moisture to complete their life cycle; in temperate climates they may be only a seasonal summer problem, but in more tropical zones or warm indoor areas, serious infestations are more common. Fleas also transmit a wide variety of diseases, including tapeworm infections and the typhus-like rickettsiae.
Adult fleas can jump long distances and readily attach themselves to animals moving through infested environments. This ability to jump also makes it possible to travel quickly from host to host and from host to hiding place for laying eggs.
In a humid environment, fleas can survive off the host for up to seven months without a blood meal. When attached to a host, they feed voraciously but digest only a small percentage of ingested blood, the remainder being excreted as small, black fecal flea dirts. Feeding stimulates egg laying while on the host and in her brief 50-day lifespan, a single female flea can lay more than 2000 eggs.
Female fleas lay eggs on the host animal, the eggs fall to the ground, carpet, sofa, dog bed, owner’s bed, or easy chair where they hatch in two-to-five days. The legless flea larva is virtually invisible for the untrained eye and feeds on protein related debris in the environment. Within a week or two, depending on temperature and humidity, the larva spins a pupa (or cocoon) to protect it during metamorphosis to the adulthood. The larvae will pupate and adult fleas later emerge from the tiny cocoons. The entire flea life cycle is completed in approximately 3 weeks under favorable environmental conditions.
Signs of infestation
Fleas can hide in pet hairs, especially on long-coated or double-coated dogs, and can move fast and freely among and between hair shafts. And because they can jump you cannot depend on seeing the flea to know if it’s there. Instead, look for clues.
If the dog scratches, he may have been bitten but he may also have dry skin, an allergy, or mange mites. If he bites at his rear end especially around his tail or the inside or outside of his thighs, fleas are a possibility. Flea dirt looks like sprinkled pepper on the dog. If you drop some of this flea dirt onto a thoroughly moistened piece of white paper it will produce reddish-brown blood stains on the paper.
Flea bite dermatitis
When feeding, fleas inject saliva into the host on which they are living. Many dogs and cats are allergic to flea saliva. Even non-allergic animals will scratch due to the annoyance of flea bites. Allergic dogs itch intensely in some or all areas of the body. They are likely to be restless and uncomfortable, spending much time scratching, licking, rubbing, chewing, and even nibbling at their skin. This often leads to hair loss, scabbing, and secondary infections. In heavy infestations (or in young puppies), anemia may develop due to the loss of blood.
Mosquitoes and flies
About 3,000 species of mosquitoes have been described worldwide. They are found from coastal plains to mountainous areas. Although the itchiness of mosquito bites is short-lived, this insect carries the heartworm microfilariae (the immature stage of the heartworm) and can transfer it to the dog. Heartworm infestations kill dogs.
All mosquitoes must have water in which to complete their life cycle. In the water the eggs develop into larvae and adults. This water can range in quality from melted snow water to sewage effluent and it can be in any container imaginable.
The feeding habits of mosquitoes are quite unique in that it is only the adult females that bite man and other animals. The male mosquitoes feed only on plant juices. Some female mosquitoes prefer to feed on only one type of animal or they can feed on a variety of animals. Female mosquitoes feed on man, domesticated animals, such as dogs, horses and cattle as well as on birds and wild animals including deer and rabbits. They may even feed on snakes, lizards, frogs, and toads.
Most female mosquitoes have to feed on an animal and get a sufficient blood meal before she can develop eggs. If they do not get this blood meal, then they will die without laying viable eggs. Adult mosquitoes are strong fliers. They can fly (or be blown) long distances from their breeding sites, although they usually go only far enough to find a blood meal.
The length of life of the adult mosquito usually depends on several factors: temperature, humidity, sex of the mosquito and time of year. Most males live a very short time, about a week; and females live about a month depending on the above factors.
If you live in mosquito country make sure to check your dog for heartworm. This is a parasite infestation in which prevention is cheaper and safer than cure and where early diagnosis is a life-saver.
Flies are prominent in tropical and subtropical countries and breed in the hot summer months in countries with temperate climates. Some flies, the nuisance flies, have mouthparts for lapping fluids and feed on the secretions around the eyes, nose, etc. Other flies, the biting flies, have mouthparts which can penetrate through the skin of the animal for the fly to feed on blood. The bites of the flies can be painful, but also, while feeding, the fly injects into the skin saliva and other substances which, for example, stop the blood from clotting as the fly feeds.
Dogs may be bothered by flies that bite their ears. In severe infestations, flies cover the dog’s ears and leave behind bloody bite marks that seem to be irritating and can become infected. Some dogs cause hair loss by rubbing their ears to relieve the discomfort.
Biting and stinging insects
Besides fleas, ticks, mosquitoes and flies, insect bites or stings can be from a number of flying or crawling insects including wasps, bees, spiders, ants and centipedes. These insects usually attack to protect themselves or their nests and their attacks can cause allergic reactions or neurological or other symptoms.
Dogs often get stung by bees or wasps, because they stalk them as prey or snap at them in irritation. Although one sting should make a dog swear off these buzzing insects, avoidance is not always possible.
Wasps become frantically active in late summer and they are aggressive about defending their nest sites. Adults feed primarily on items rich in sugars and carbohydrates, such as fruits, flower nectar, and tree sap, and larvae feed on feed on proteins, such as insects, meats, and fish. Adult workers chew and condition the meat fed to the larvae. Larvae in return secrete a sugar material relished by the adults. In late summer, foraging workers change their food preference from meats to ripe, decaying fruits, or scavenge human garbage, sodas, picnics, etc., because the larvae in the nest fail to meet the worker’s requirements as a source of sugar. Wasps are fierce competitors for food and often attend late summer picnics and swarm around trash barrels, hazards to people and pets alike.
Paper wasps are wasps that gather fibers from dead wood and plant stems, which they mix with saliva, and use to construct water-resistant nests made of gray or brown papery material. Paper wasps will sting dogs or humans and generally only attack if they themselves or their nest are threatened. Since their territoriality can lead to attacks on people and pets, and because their stings are quite painful and can produce a potentially fatal anaphylactic reaction in some individuals, nests in human-inhabited areas may present an unacceptable hazard.
Bumblebees and honeybees round out the group of flying insects. Although they are not particularly aggressive, they will sting if annoyed sufficiently.
Spiders hunt in the garden, house and garage, and settle wherever prey is to be found. Spiders may bite if picked up, stepped on, or startled by a waking dog. The bite may leave an itchy or painful welt or could cause more generalized symptoms. If you suspect your dog has been bitten by a spider or many spiders, call your veterinarian.
Although ants will bite if disturbed, few dogs will bother them because they taste bad. So, unless your dog strolls through an ant nest, he’s unlikely to be annoyed by them.
Technically speaking centipedes are not insects because they have more than six legs, but they are closely related invertebrates. They have long, segmented bodies with one pair of legs on each segment. Centipedes have a pair of poison claws behind their heads and use the poison to paralyze their prey, usually small insects. However, the jaws of centipedes are weak and can rarely penetrate human or dog skin. The rare individuals who are bitten may experience localized swelling and pain no worse than a bee sting.