Aug 22 2014

Constant Vigilance: Fall Flea And Tick Prevention

Lyme 1School starts next week and in no time, we will all be putting away our summer clothing and winding down the gardening activities in favor of leaf sweeping and football.  With low temperatures predicted to dip into the 60’s, it can be easy to be fooled into thinking our pets don’t need their flea and tick prevention until next summer.

In reality, fall is one of the most common times to become infected with Lyme Disease.

Both species of tick known to transmit Lyme Disease in the United States have two year life cycles.  As with all species of ticks, both the deer tick and the western black-legged tick require a blood meal to move to each stage in the lifecycle.  It takes approximately two years for these ticks to hatch, go through the three growth stages (larva, nymph, adult), reproduce and then die.  Each part of this cycle is seasonal.

Let’s look at this graphic from the American Lyme Disease Foundation.  In the spring, the adults lay eggs.  The eggs hatch into larvae later in the summer.  At this point, the larval form is not infected with the bacteria that causes Lyme Disease.  Larva stay on the ground until a bird or a mammal brush up against them.  The larva hitches a ride, attaches and takes a blood meal.  If the host is infected with the bacteria, the larval form of the tick becomes infected at this time.  Larvae reach their peak activity in August.  After feeding, they drop off the host, develop into nymphs and remain inactive until May.

In May, the nymphs seek out hosts and feed again.  In this stage, nymphs that are already infected can pass along the disease to their hosts, including dogs and humans.  Nymphs are extremely small and are responsible for nearly all human cases of Lyme Disease.  Once a nymph is engorged, they drop off the host, molt into adults and spend the fall actively seeking new hosts.  Adult deer ticks that are successful will feed, mate, lay eggs and then die.  Adult ticks that do not find a host become inactive throughout cold weather, emerging in late February or early March to continue their search.  One adult female tick lays about 3000 eggs.

Part of your dog’s yearly wellness visit is a blood test for heartworm disease, Lyme disease, and two other tick-borne diseases.  When a dog tests positive for Lyme disease, most of the owners have no recollection of a tick bite on their pet.  As previously mentioned, nymphal forms of the ticks are extremely small and extremely hard to see.  In addition, dogs do not get the traditional bulls eye rash associated with Lyme disease.  If your pet has a thick or dark coat, even adult ticks may be hard to find.  Ticks also attach in places that an owner wouldn’t see a tick unless they were actively looking, like inside ears or between toes.

Adult ticks generally become inactive at temperatures below 45 degrees F.  Until such weather approaches, you should assume that the adult ticks in the vicinity are actively seeking out new hosts, be it you or your pet, in order to take a blood meal and complete their life cycle.

As for fleas, there are four stages to their life cycle: egg, larva, pupa and adult.  Humidity and temperature have a lot to do with how long this four part cycle takes to complete.  Optimal conditions for fleas are between 70-85 degrees F and 70% humidity.  The pupae stage, or cocoon stage, can protect the developing flea for months or even years.  While this stage is present in smaller amounts (roughly ten percent of a flea population, when you include all life stages), it is the most hardy.  The cocoon has a sticky outer layer that prevents it from being removed by light vacuuming or sweeping, and it protects the flea from chemicals.

A flea will remain in the cocoon stage until presence of a host is clear.  For fleas, this means rising levels of carbon dioxide and body heat.

Consider this scenario: in the summer, air conditioning removes humidity from the air in your home, lowering levels to less than optimal conditions for flea development.  All summer, cocoons can stay hidden and dormant in your home.  One of two things usually happen.  You either go on vacation, turn off the AC and let the house sit shut up and hot, or the outside weather cools slightly and you turn off the AC and open the windows.  In both scenarios, the increase in humidity within your house combined with rising temperatures is usually enough to trigger pupal stages into waking up and hatching into adult fleas.   Since most of us tend to keep our homes in the 68-72 degree range year round, there is no time to assume that fleas are not capable of hatching and biting, should you have a population inside.  Temperatures outdoors have to approach freezing and stay there for at least ten days before fleas and the various parts of the life cycle will die.  This past winter was a great winter for flea death, but we’ve had far too many warm winters to be able to really count on the temperature as flea control.

Fleas and ticks are capable of spreading disease and causing sickness such as anemia.  In addition to the health aspect, one adult flea can bite up to 400 times in one day, which is pretty uncomfortable for your pet at the very least!

To prevent and control fleas and ticks, we carry many different options.  Activyl, for dogs, is a topical applied once a month that kills ticks and adult fleas and stops eggs and larvae from developing.  Revolution, for cats and small dogs, prevents fleas and ticks.  Program Injectable, for cats, helps prevent indoor infestations for indoor only cats and lasts for six months.  Nexgard, for dogs, is an oral chewable tablet given monthly for fleas and ticks and is a great option for dogs that can’t tolerate a topical medication.

 

 

 

 

bsah6244 | parasites, Preventative Medicine, Seasonal Health

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