Saturday, May 31, 2008

Ticks and Ehrlichiosis, Part 1

Photo  of red (or brown) dog ticks taken from Lyme Disease Foundation Website, tick identification page.

This post became so long that I've split it up into two parts.

Where we lived in western Washington, there were no ticks, but fleas were a really bad problem.  Very reluctantly, we used one of the insecticides on our animals that you apply in one spot to the skin during flea season.  I say "reluctantly", because as a biochemist, I'm aware that almost always, what is harmful to one form of life is harmful to other forms of life--the only difference is degree.  Too many effects are cumulative, and I resist putting our beloved dogs and cats at risk.  I will use anti-helminthics when needed; wherever you have a big flea problem, there, too, you have a big tapeworm problem.  But the "spot" insecticides?  Only during the months when fleas were a problem, never year round.  We had a wonderful Cairne terrier who at 10 died from a brain tumor.  After she died, we noticed a discolored spot on her back between her shoulder blades where we used to apply the insecticide.  I don't know if there was any correlation, but it just added to my skepticism about the use of these chemicals.  However, you have to make these risk/benefit decisions.  I knew someone back in Washington whose standard poodle died from anemia because of an uncared-for flea problem.  You have to choose the lesser of two evils and hope.

We'd heard from acquaintances in Boquete that fleas were a big problem there and assumed it would be true where we lived, but to my delight and relief, our vet told us that we didn't have to worry because it was too hot for fleas to survive in Potrerillos. And it's true that in the 4 years we've been here, we've had no signs of fleas except when we brought Rickie and Senna, our kittens, home from the cat rescue place in Boquete. After getting rid of Senna's fleas, we've had no trouble.

We were told, however, by our extraordinarily helpful American neighbor that ticks were pretty bad.  We also discovered that the spot insecticide available here, Revolución, was NOT effective against all the tick species in the area.  So we resorted to combing the dogs twice a day (we just had Lucy and Ethel then--Fred's a Panamanian), and I was introduced to the joys of removing ticks from both the dogs and me with a tweezers.  

We really didn't have that much of a problem, except for one day when we removed 6 ticks from Lucy's neck.  Ugly but we had it under control.  After we bought our property a short distance away, we noticed that every time we went there with the dogs, they would come back with ticks.  At that time, the place was an overgrown unused pasture, filled with high grass, weeds, shrubs and young saplings.  Perfect tick territory.

Even before we moved into the house, we had the property "cleaned", as they say here, by two young men with machetes.  I bought a heavy-duty weed eater, and got to work maintaining.  As I brought more and more of our 3+ acres under control, mostly with weed eater and machete, and then, as we cleared, with a lawn mower, our tick problem pretty much disappeared, despite our bovine neighbors.

We used to walk the dogs in a pine woods close to the property, and there, of course, we'd come across ticks. I'll never forget the day last year when Fred suddenly started shedding little brownish-red spots--that moved. The next 24 hours were a nightmare as we kept combing ticks from him, committing mass tick murder. I'm sure we removed or he shed over 100 ticks. We figured he must have picked them up in the woods or had a hatchout on his coat (which doesn't seem too likely but then who knows). All I knew at the time was that they were the little brown ticks that another American complained were not affected by the common spot insecticides available here. I had no idea then that they were one of the species of dog ticks.

We don't walk the dogs in the woods anymore because Fred the Happy Lab Wanderer will bolt and run off to play with one or more of the horses in the neighborhood; it's a royal pain in the buns to chase him around until he's finally tired of playing with us and trots up for his lead.  doesn't matter that he spends the next 5-7 hours in his crate, thinking over his sins; after contemplation, Fred is totally unrepentant and is ready to go play games with whatever large, unfriendly animal is handy.

Since we stopped the woods walks, we've had very few incidences of ticks.  One of which occurred this morning, when we removed a common dog tick from Fred.

One of our American friends participates actively in a spay/neuter program that was originally a Panamanian/American joint venture started in Boquete.  Stray dogs and feral cats are a problem, and the program offers either free or very low cost spaying and neutering for pets.  In addition, many of the volunteers use humane traps to catch feral cats in particular and bring them in to the clinics which are held about every 6 weeks, I think.  It's an outstanding way to reduce the stray population.   I was told that they routinely test for Ehrlichiosis, which is a really nasty disease transmitted by ticks.  I had never heard of it before I came here.  We don't have Lyme disease here, for which I'm grateful, but Ehrlichiosis is supposedly becoming more of a problem because of the large numbers of stray animals in Panamá.  

I also learned that an ex-pat--An American, I believe--in Potrerillos had come down with Ehrlichiosis and was gravely ill, taking a long time to recover.

Then our next door neighbors' cat, Chloe, got very sick.  To make a long story short, she was diagnosed with Ehrlichiosis, which completely flabbergasted her owners who have been importing special flea collars that supposedly is effective against both types of dog ticks.  To make another sad story short, after a heroic 2 month effort on Marion's part, they were forced to have Chloe put down.  All of us who live with and love our animals know what that decision costs.

Now worried, we began an earnest research effort into Ehrlichiosis.  I'll give you a very brief summary:

Ehrlichiosis is a relatively newly-identified tick-borne disease. Ehrlichiosis is primarily a problem with dogs; it's very rare in cats. It can also occur in humans, where it's very serious indeed.  Erlichiosis is transmitted by several tick species but mainly by the two dog tick species, R. sanguineus and D. variabilis.  R. sanguineus is the most usual culprit.  Evidently the human form of the disease can be transmitted by a number of other ticks, such as the lone star tick, the deer tick, and others.  It's hard to tell from what's available online, because in humans the disease is difficult to identify and can be confused with other rickettsial diseases.  Ehrlichiosis is widespread in the US, although it occurs mostly in the southwest and south.  California seems also to  be a hot spot, especially southern California.

The disease has two stages in dogs, an acute and a chronic phase.  I've copied a short summary of symptoms from an article in Wikipedia:

"The acute stage of the disease... begins one to three weeks after infection and lasts for two to four weeks. Clinical signs include a fever, petechiae, bleeding disorders, vasculitis, lymphadenopathy, discharge from the nose and eyes, and edema of the legs and scrotum. There are no outward signs of the subclinical phase. Clinical signs of the chronic phase include weight loss, pale gums due to anemia, bleeding due to thrombocytopenia, vasculitis, lymphadenopathy, dyspnea, coughing, polyuria, polydipsia, lameness, ophthalmic diseases such as retinal hemorrhage and anterior uveitis, and neurological disease. Dogs that are severely affected can die from this disease.
Although people can get ehrlichiosis, dogs do not transmit the bacteria to humans; rather, ticks pass on the ehrlichia organism. Clinical signs of human ehrlichiosis include fever, headache, eye pain, and gastrointestinal upset. It is quite similar to Rocky Mountain spotted fever, but rash is not seen in patients."

Treatment is usually with doxycycline, a member of the tetracycline family of antibiotics.  Catch it in the acute phase, and the dog usually recovers.  If it enters the chronic phase, the risk of death is much, much higher.

This is by no means an exhaustive explanation--ti's incomplete, as a matter of fact-- and you should consult your vet for local levels of problem and far more inclusive information.  No one should EVER make an amateur diagnosis about any disease that show symptoms such as fever.  I freely admit to overreacting to anything that seems wrong with our animals.  I usually have to force myself to wait the classic 24 hours before whisking one of our precious babies to the vet.

This disease and its transmission have not been all that well studied even in the US, and one of the things you learn fast here is that in the tropics, all bets are off.  We medicate our animals against a much broader spectrum of parasites than exist in the US.  In the US, the dogs would get their annual baths; it really is not in their best interests to bathe them too frequently in temperate zones.  Here, as I've mentioned, ideally we should be bathing them every two weeks.  while it's more like every 3 weeks, we are far more serious about dog bathing, thanks to experiences with demodetic mange, seborrheic dermatitis, and fungus diseases.  Fungus diseases are rampant in this climate.  Fred in particular is susceptible to them.  

The humidity and heat of the tropics means that lots more nasties can live here, and they even can mutate faster than in temperate zones.  Perhaps you remember the Ebola virus?  Originated in the equatorial zone of Africa, as did the AIDS virus.  I've read speculation that the reason that hominid species very early on migrated away from these zones is that they are mutational "hot spots", where new forms of life can originate very rapidly through mutation, thanks to the heat.  Just one of the more important chemical facts; the rate of any chemical reaction doubles with every 10 degrees Celcius rise in temperature.  All life is based on a set of incredibly complicated cellular chemical reactions.  For mammals, exterior temperature is not all that important, because we are creatures that regulate our internal temperature to stay within very narrow limits.  But bacteria and viruses do not do so, and of course, the warmer it is (up to a killing temperature), the faster they'll reproduce (which is why we refrigerate sensitive foods like meat, to slow the process down) and the higher the likelihood of mutations.

You know, it just dawned on me why I blog the way I do--I really miss teaching!

Enough about personality disorders and back to problems here in Panamá in Part 2 tomorrow.

2 comments:

MxSailor said...

Stumbled across your blog because we too, have tick problems. I've purchased some "Bio-Blast" to try spraying around the "yard." Already approved by FDA for treatment of ticks as well as termites... let you know what I find...

BIO-BLAST: A fungus, Metarhizium anisopliae, Strain ESCI (Bio-Blast) acts as a biological termiticide. It is odorless, vaporless, nonstaining and infected termites can pass the agent (fungus) to other termites via horizontal transfer. Bio-Blast is labeled for control of existing termite infestations in structures and their immediate surroundings and for residual protection of treated wood. Spray effectiveness is enhanced when applied to many foraging termites. Treated termites return to the colony, spreading the biological active ingredient to others. Treatments can be made both indoors and outdoors.



Adapted from the Ohio State University Extension, 1999

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Joyce said...

Thanks, MXSailor! This is a really interesting piece of information. As I've mentioned, our tick problem has been reduced to an occasional incident, but we're pretty sure that what few we have are coming from the cattle ranch next door. It would be easy for us to treat along that fence line. Also, horses are supposed to be much worse attractors of ticks. One of our neighbors has a terrible problem with ticks because they have a horse. I'm going to pass this information along specially to them.

Joyce