Written by Vasiliki A. Ntavlourou. BVM, GPCert(ExAP),MRCVS. Written 2014, Revised 2016.
In this article you will find all information and valuable advice relevant to a very common (in Greece) canine disease. EHRLICHIOSIS!
As with all articles published on my website, my aim is to inform those (owners or not) interested in animal welfare and protection of pet animals from common diseases and accidents.
These are not scientific articles addressed only to specialists of the veterinary profession. Therefore, the language I use, is as simple and scrutable as possible . This of course,does not mean that the contents of my website have no scientific ground. For every article I publish, I dedicate hours and days of research and studying and I use numerous valid scientific sources, combined with my knowledge and experience gained throuthout the years of actively practicing as a Veterinary Surgeon.
At the end of each article , all the relevant references where I borrowed the information and knowledge from in order to transfer it to you, are mentioned.
ΕHRLICHIOSIS
OR
TICK-BORNE DISEASE!
Canine Ehrlichiosis is an important disease of dogs with a wide distribution in Asia, Europe, Africa and America.
Unfortunately, Ehrlichiosis and Leishmaniosis are very common diseases in Greece and acountable for many deaths in the canine population every year!
Dog owners living in or travelling to Greece and other endemic areas (areas where the disease is regularly found), should be informed of both Ehrlichiosis and Leishmaniosis and fully aware of the risk of disease transmission to their pets.
This article's aim is to inform and educate dog owners on Ehrlichiosis and help them detect early the clinical signs of this fatal disease in order to seek Veterinary advice!
Μy personal opinion is that despite the available treatment methods and successful outcomes in most cases of Ehrlichiosis, compared to Leishmaniosis, this disease can be more dangerous and prove detrimental, mainly due to the lack of education of dog owners regarding the health risks involved in the otherwise "common" presence of TICKS on their pets. Also, I would characterize this disease more "silent" and "insidious" compared to Leishmaniosis.
What I mean by this,is that most dog owners in Greece are now very well informed of the disease of Leishmaniosis and especially on the ways of transmission of this disease, via mosquito bites during the summer months. On the other side, the percentage of owners who are aware of the fact that ticks not only feed on their dogs' blood but they can also transmit fatal diseases, is considerably low.
Another interesting point that supports my above statement, is that although both Leishmaniosis and Ehrlichiosis are blood borne diseases, Leishmaniosis in the majority of clinical cases manifests with cutaneous lesions which makes early recognition by the owner easier and in many cases proves life saving! Ehrlichiosis on the other hand, does not cause characteristic skin lesions on the dog ,unless the disease has already progressed and caused generalized hemorrhages-"petechiae" on the skin and mucous membranes of the animal.
(Petechiae on the skin of a dog diagnosed with Chronic Erhrlichiosis. Photo. from the clinic's archive)
The absence of characteristic external clinical manifestations of Ehrlichiosis together with its variable clinical presentation, is mainly responsible for the delayed diagnosis and quite often the poor prognosis for the animal that is finally found to be suffering from this disease.
♦It is true that a large number of dogs suffers from Leishmaniosis in Greece (Kala-azar). But it is also true that an equally large number of dogs is daily diagnosed with Ehrlichiosis and sadly dies of this disease.
♦Most dog owners in Greece are now well educated regarding the preventative health checks and blood tests their animals should be having every year for the disease of Leishmaniosis.
It is our duty as Veterinarians to inform owners of all the necessary preventative health checks they should be perfoming yearly οn their pets. The experience I gained after practicing as a Small animal clinician for the last 7 years in Greece, allows me to advice that a specific blood test for Ehrlichiosis (and other Tick borne diseases!) or at least a CBC (complete blood count) which would give valuable information towards the diagnosis of a Tick borne disease, should be added to the yearly health check of every dog in Greece (or every dog that has travelled to Greece and other endemic areas during the warm months of the year).
I reached this conclusion, after having diagnosed Ehrlichiosis in a large number of cases, having also noted that in most of them, the owner would report minor clinical signs such as: short term loss of appetite, reduced stamina or levels of activity (which most of the owners would blame on the extreme summer temperatures in the country). These non specific clinical signs would not normally refer to something as serious as Ehrlichiosis. In other cases, the diagnosis was reached (and it came to our surprise too!), after a noticeable lameness and/or swelling on one (or more) of the dog's legs and this would be the only reported clinical sign by the owner.
Another VERY interesting point is that in the majority of confirmed cases of Ehrichiosis in our practice, the owners had not found (or noticed) any ticks on their dogs and for this reason I would like to emphasize on the following advice:
THE ABSENCE OF TICKS FROM THE DOG'S SKIN DOES NOT PRECLUDE THE POSSIBILITY OF DISEASE TRANSMISSION!!!! Ehrlichiosis is transmitted via TICK BITES, which means that if at any stage your pet was attacked (bitten) by a tick, it could have potentially transferred the disease to your animal. If the animal is protected via routine treatment against ectoparasites, the tick will surely not survive long on the animal, but sadly enough, blood sucking is enough for the disease to be transmitted.
DO NOT RULE OUT EHRLICHIOSIS AS A POSSIBLE CAUSE OF YOUR DOG'S MALAISE, ONLY BECAUSE YOU HAVE NOT FOUND ANY TICKS ON IT.
I do hope that in this article you find all valuable information regarding the aetiology, clinical presentation, diagnostic methods, treatment options and preventative measures for this dangerous disease. It is my wish for dog owners to learn about Ehrlichiosis only by reading my article and not by having to treat their beloved pet.
Most of all I aim in the awareness of readers, whether they live in or travel to endemic areas (areas where the disease is commonly found), regarding the tremendous need for appropriate prevention and fighting off ectoparasites (fleas and ticks), not only for the protection of their pets but for their own as well!
-WHAT IS THE CAUSE OF EHRLICHIOSIS?
Canine Ehrlichiosis is a very serious blood borne disease caused by obligate intracellular bacteria of the genera Ehrlichia. Natural infection of the dog occurs when an infected tick ingests a blood meal and salivary secretions contaminate the feeding site. Iatrogenic spread can occur with blood transfusions from infected donors.
These bacteria belong to the order Rickettsiales with their most important families being: Rickettsiaceae and Anaplasmataceae. In the family of Anaplasmataceae belong the most important (for Veterinary and Human medicine) species: Ehrlichia canis, Ehrlichia ewingii and Ehrlichia chaffeensis.
The above species of Ehrlichia have quite a few differences between them, as far as their "vectors" (different types of ticks), "hosts" (dog, human, horse etc.) and invade different types of blood cells once inside the organism.
One of the most important new developments related to Ehrlichiosis is the realization that a given mammalian species can be infected simultaneously or sequentially by several Ehrlichia species.Fortunately, all these different species of Ehrlichia are sensitive to the same group of antibiotics and the clinical presentation as well as hematological abnormalities caused by the different species of Ehrlichia are similar (very helpful in the diagnosis of the disease).
Ehrlichia canis is the most common species and responsible for the most severe form of this disease in the dog (Monocytic Ehrlichiosis). E.canis was identified for the first time in 1935 and since then there was an increasing interest in this disease, especially during the war in Vietnam when hundrends of military dogs (mainly German Shepherds) died of Ehrlichiosis.
Ehrlichia canis has a worldwide distribution (Asia, Africa, Europe, America), most commonly found in countries where the climatic conditions favor the survival of ticks in the environment!
Countries such as the United Kingdom where a strict quarantine policy was and still is applied, are free of this disease, despite the presence of ticks in these countries too.
The microorganism of Ehrlichia is transmitted via tick bites, more precisely via the brown tick-Rhipicephalus sanguineus. This is a tick with worldwide distribution that can survive indoors throughout its entire life cycle (unlike other tick species). It is the tick most implicated in home and kennel infestations. (This tick is also vector for Babesia canis and Anaplasma platys).
During the ingestion of a blood meal, the infected tick contaminates the feeding site with its salivary secretions. For the tick to get infected, it must ingest a blood meal from an already infected host (dog). A host that is already in the "acute" phase of the disease.
(Photo.borrowed from internet source)
After the ingestion of contaminated blood, the tick transfers the disease to the next "victim", the next host that will get bitten (eg.the next dog). Ticks can get infected at any stage of their biological cycle!
(Photo.borrowed from internet source)
(Photo. from the clinic's archive)
Τicks can remain infectious (maintain their ability to transfer the infection) for 155 days after their own infection! Therefore, not only contribute to the disease transmission but also to the preservation of the disease in the environment. In order for the microorganism of Ehrlichia to survive once inside the dog's body, it must enter the blood cells of the animal (in particular the WHITE blood cells), where it multiplies and then spreads. E.canis enters the blood cells called "monocytes and "macrophages".
E.canis inside a "macrophage". (Photo. borrowed from Internet source)
Ehrlichia spp. inside a "neutrophil.(Photo. borrowed from Internet source)
Ehrlichia ewingii inside a "neutrophil". (Photo.borrowed from Internet source)
Tick's intervention for the disease transmission between dogs is absolutely necessary. In theory, dogs that live in areas "free" of ticks, are not at risk of contracting the disease from infected dogs in their proximity.
Another way of disease transmission (Iatrogenic) is a blood transfusion. For this reason, all canine donors in endemic areas should be checked prior to donating their blood!!!
Ehrlichia ewingii, (very common in the USA), is aparently less dangerous for dogs, causing a milder form of the disease. Polyarthritis is among the most predominant clinical signs. Its vector, Amblyomma americanum (Lone star tick) is an "aggressive" tick species and feeds on multiple wild and domestic species, including dogs as well as humans.
Ehrlichia chaffeensis is considered the aetiologic factor of Human monocytic Ehrlichiosis and is transmitted by Ambylomma americanum (Lone star tick).
-WHAT HAPPENS AFTER A DOG GETS INFECTED BY EHRLICHIA?
A very important point that should be highlighted from the beginning (and you might see it mentioned quite often in my article on Leishmaniosis), is that the disease's progression from the moment of infection depends on quite a few factors, such as:
1. The species and potency of the responsible for the infection microorganism (different species of Ehrlichia ).
2. Other diseases the same animal might be suffering from at the same time!
3. The most important factor of all: HEALTH STATUS AND INTEGRITY OF THE DOG'S IMMUNE SYSTEM!!!!
I do not consider it just a "bad coincidence" the fact that a great number of dogs that suffered from Ehrlichiosis, when checked hematologically where found positive for the disease of Leishmaniosis as well!!!
For those frequent visitors of my website as well as those visiting our clinic, the following advice is well known and maybe boring, as I do repeat it in every given chance:
Always take care of your animal's general health status and apply all routine methods for the prevention of parasite infestation (endoparasites as well as ectoparasites). Perform routine yearly Veterinary checks on your pets and have the booster vaccinations done every year!
AN OTHERWISE HEALTHY DOG HAS MORE CHANCES OF SUCCESSFULLY FIGHTING AGAINST A DISEASE SUCH AS EHRLICHIOSIS OR LEISHMANIOSIS WHEN THE IMMUNE SYSTEM IS STRONG. ON THE CONTRARY, AN ANIMAL THAT SUFFERS AT THE SAME TIME FROM OTHER "SIMPLE" PROBLEMS LIKE WORMS FOR EXAMPLE, HAS A WEAK AND FRAGILE IMMUNE SYSTEM THAT WILL NOT BE ABLE TO FIGHT OFF SUCH A SERIOUS DISEASE, DESPITE THE ADMINISTRATION OF STRONG AND "EXPENSIVE" MEDICATION.
Immunocompromised animals will develop Ehrlichiosis in its most severe form. The age or sex of the animal are of minor importance in the infection. As far as the breed of the dog, research has proved that German Shepherds are more sensitive compared to other breeds and when the disease develops in this breed, it has a less favorable progression and most often a poor prognosis. The difference between breeds as far as the progression of the disease is related to the ability of their immune system to fight off the infection. For the German Shepherd dog in particular, it has been proved scientifically that the cellular immunity of their organism against E.canis is reduced compared to other breeds (e.g. Beagles!)
The incubation period (time between infection and clinical development of the disease), is usually 8-20 days. Within this period of time , the microorganisms of Ehrlichia mutliply inside the blood cells and spread inside the dog's body.
My advice to all dog owners is to seek Veterinary advice and have blood tests done on their pets within a month (the latest or a lot sooner if the animal is showing signs of illness) , after the detection of a tick (or ticks!) on them!
-WHAT IS THE CLINICAL PRESENTATION OF A DOG THAT SUFFERS FROM EHRLICHIOSIS?
All the clinical signs and symptoms described below, refer mainly to the infection of a dog by E.canis (the most common cause of infection in dogs). It is very important to repeat and clarify that the disease of Ehrlichiosis is caused by different species of Ehrlichia. It is also important to highlight that other, similar to Ehrlichiosis diseases can be transmitted via tick bites and their diagnosis requires specialized laboratory tests.
Experimental studies so far have shown that Ehrlichiosis can be divided into 3 disease stages:
1.ACUTE
2.SUBCLINICAL
3.CHRONIC
This differentiation is based on the different clinical signs and symptoms as well as the different hematological abnormalities identified in animals diagnosed with Ehrlichiosis (in experimental conditions).
In natural infections, the above differentiation is often difficult.
A detailed history together with a thorough clinical examination of the animal by an experienced Veterinary surgeon who has studied this disease in depth, allows an early diagnosis even in cases of natural infection. In Greece where the climatic conditions favor the survival of ticks throuthout the year (even in the winter!), Ehrlichiosis should be part of the differential diagnosis in every dog that presents with suspiscious clinical signs, without taking into consideration any seasonal factors***.
***The seasonality of this disease refers to the transmission ONLY by ticks, mostly during the warm months of the year and NOT to the clinical presentation of the disease which can vary (from a few days to months or even yeras!!!) after the infection. (So, that the title of the article-SUMMER NIGHTMARE-is not misleading!)
Even more, it is my opinion (based on the number of dogs already diagnosed with Ehrlichiosis in our clinic) that an annual diagnostic blood test for this disease together with Leishmaniosis, should be included in the routine health check of every dog living in or travelling to endemic areas.
1.ACUTE PHASE
The acute phase of this disease usually has a duration between 2 and 4 weeks. It is characterized by transient illness that largely goes unrecognized. In other words, the clinical signs and symptoms developed during this phase MIGHT be detected by the owner and if Veterinary assistance and advice is given on time, then the outcome is more likely to be successful. The severity of symptoms in this phase depends on many factors and it is definitely not the same in all dogs:
Among the most common clinical signs are: fever, loss of appetite, lethargy. Less commonly a dog with a weak immune system suffering the acute phase will develop more severe clinical signs : petechiae and bruises, epistaxis (bleeding from the nose), splenomegaly, lymhadenopathy.
Central Nervous System clinical signs and symptoms may also manifest during the ACUTE phase of Ehrlichiosis. HYPERESTHESIA and Muscle twitching are quite characteristic.
HYPERESTHESIA is one of the most "impressive" clinical signs of Ehrlichiosis and quite often the only one reported by the owner. A typical description by the owner is that the dog seems to be in a lot of pain in almost every part of its body. A pain reaction and "cry" is usually reported as a result of handling or even just "touching" the animal. These dogs refuse to move due to the pain and prefer to sit or lay down.
It is true that only a few owners will seek veterinary advice and help after the first short term illness of their pet. But even then, the clinician might find it very difficult to convince the owner that there is need for specific blood tests, especially in those cases where the owner insists that he/she never found any ticks on their pet.
In my experience, dogs that were diagnosed early enough (during the acute phase), were those that presented with mild symptoms such as: loss of appetite and mild exercise intolerance. Most of the times, in these cases the owner would blame the animal's condition to the extreme summer temperatures in the country. In these cases it was thanks to our persistence that an early diagnosis was reached and as a result a successful outcome achieved.
REMEMBER: IT IS NOT NECESSARY TO DETECT TICKS ON A DOG IN ORDER TO DIAGNOSE EHRLICHIOSIS. THE DISEASE IS TRANSMITTED VIA TICK BITES!
Most of the animals nowdays are routinely protected via spot on, spray or oral products against ectoparasites. What most owners are not aware of though, is that all these licensed paraciticide products (so far-2016!), ONLY kill ectoparacides after they attack the animal! These products DO NOT have a repellent action!!!! In other words, the tick has to feed on a dog (that has been covered with ectoparaciticide products) in order to die!
Fleas and Ticks are NOT aware of the fact that your dog has been treated against them with ectoparaciticide products. The tick will get on your dog, will bite and suck blood and then it will drop dead! But it got attached and bit your dog, which means it exchanged infected saliva with blood! So, there is a good chance that the disease got transmitted!!!
Products with repellent action are effective against mosquitos. Ticks and Fleas though, are NOT mosquitos! A few articles have been published on the possibly effective use of products containing essential oils and their repellent action against fleas and ticks. There is need for further research for effective acaricides and products with strong repellent characteristics, so as to prevent tick attachment!!!
Products against mosquitos are different to those against fleas and ticks!
Hematological changes possibly noticed in a dog with ACUTE Ehrlichiosis are: mild reduction in the number of Platelets, mild leucopenia (reduction in the total numbers of white blood cels), and Mild Anemia.
The majority of animals that will receive treatment on time, will recover fast and completely. Animals that did not get diagnosed during the acute phase or did not complete the full treatment plan, have a good chance of recovering spontaneously if their immune system is healthy and strong. Otherwise, they will enter the SUBCLINICAL phase of the disease.
2.SUBCLINICAL PHASE
During this phase, the animal shows no major signs of illness but it remains bacteremic (Ehrlichia bacteria remain in the blood stream). In fact, most of the times it is reported by the owner that the dog got better! This is not entirely false, because it is true that some dogs recover spontaneously from the subclinical phase with or without treatment. The immune system of the animal might be able in some cases to fight off the disease during the initial acute phase or in some other cases an incomplete treatment might be enough to give temporary good results. So, we might notice that the dog's appetite and lost weight are regained, the fever subsides and generally the animal is gradually looking better and almost back to normal!
THIS, IN MY EXPERIENCE IS THE BIGGEST "PITFALL" OF EHRLICHIOSIS.
Those "lucky" animals that managed to survive the ACUTE phase of Ehrlichiosis but their immune system did not completely extinguish the disease, sooner or later will enter the "CHRONIC" phase of the disease and a high percentage of them will sadly die, despite all the efforts and appropriate treatment.
Missing the diagnosis of Ehrlichiosis is to be blamed partly on the owner's denial to seek Veterinary help when the animal has "magically" got better or the Vet's inexperience in dealing with this disease, but also on the individual animal's immunologic response.
The cost of extended diagnostic tests is considered another inhibitory factor that quite often leads to diagnostic failure.
In the SUBCLINICAL phase, most of the clinical signs that would support the diagnosis of this disease, are missing. A mild reduction in the total number of platelets on the bloed test, could be the only suspiscious finding that would lead to diagnosis, but it is not always present. Therefore, a specific serological test and detection of specific antibodies against Ehrlichia is absolutely necessary at this stage.
The duration of the SUBCLINICAL phase, varies a lot. In some cases, the animal can enter the carrier stage and remain a carrier for a very long time (months to years!). Research has proved that in some cases, Ehrlichia bacteria can remain and "hide" inside the dog's spleen for years! This is why in experimental infections, it was found that animals that had undergone splenectomy, developed only the mild form of Ehrlichiosis. Because of chronic subclinical infection, a dog can be transported from an endemic to a nonendemic region and subsequently develop disease manifestations years after the initial infection.
3.CHRONIC PHASE
The CHRONIC phase has a grave prognosis due to BONE MARROW hypoplasia, reduced production of blood cells that leads to Pancytopenia (reduction in the numbers of all white blood cells) and loss of immune competence. The CHRONIC disease is usually lethal despite treatment.
♦ PREVENTATIVE BLOOD TESTS AND FAST DIAGNOSIS OF EHRLICHIOSIS TOGETHER WITH STRICT TICK CONTROLS ARE IMPERATIVE.
-WHAT ARE THE CLINICAL SIGNS AND SYMPTOMS OF EHRLICHIOSIS?
The following clinical signs and symptoms refer to dogs affected by Erhlichia canis, although most Ehrlichia spp. cause similar clinical signs.
Canine Ehrlichiosis manifests with a wide variety of clinical signs and is quite often referred as a POLYSYSTEMIC disease. A disease that develops with a variety of symptoms (specific and non specific) from nearly all body systems.
EHRLICHIOSIS (AS WELL AS LEISHMANIOSIS), ARE NOT ALWAYS FOLLOWED BY SPECIFIC CLINICAL SIGNS AND SYMPTOMS.
There is common or more characteristic clinical signs but these could also manifest in a long list of other diseases.
Some of the clinical signs and symptoms reported frequently in EHRLICHIOSIS are:
1. Fever, Lethargy, Weakness, Loss of appetite, Mild loss of body weight.
2. HEMORRHAGES (BLEEDINGS)!!!!
Bleeding is possibly the only sign that could be characterized as "pathognomonic" (specific to the disease), although it is quite often present in other diseases (e.g. Leishmaniosis) too.
The most common site of bleeding in the animal's NOSE and this type of bleeding is called : EPISTAXIS!
Other common sites of bleeding could be : the mouth, the genital tract, the gut.
Bleedings show up on the CBC (general blood count) as ANEMIA which is REGENERATIVE in the ACUTE phase of the disease or NON REGENERATIVE in the CHRONIC phase.
(PHOTO. from the clinic's archive)
EPISTAXIS (bleeding from the nose) is definitely one of the most characteristic signs of this disease and one should immediately suspect Ehrlichiosis-in dogs that live in or have travelled to endemic areas- but other causes of the bleeding should also be considered:
♦ Leishmaniosis
♦ Rat poisoning (or other intoxication!)
♦ Αutoimmune Thrombocytopenia
♦Foreign bodies/Injuries
♦Tumors
etc.
(Melena: dog's feces with blood due to CHRONIC Ehrlichiosis. Photo. from clinic's archive.)
Bleeding due to Ehrlichiosis though, is not always as obvious! It can manifest as "petechiae" ,"ecchymoses" or "bruisings"
of the skin and mucous membranes!
All the above terms refer to skin or mucous membrane discoloration, typically due to injuries that lead to bleeding (hemorrhaging) under the affected area. Sadly, when these lesions have developed on a dog's body, the disease is already advanced!
"Petechiae" are small, red or purple spots on the skin or mucous membranes caused by minor hemorrhaging. They can appear anywhere on the body or inside the mouth of the animal (gums, mucous membranes).
"Petechiae" are not easily detected by the owner or when spotted, are quite often mistaken for "skin rashes"!!! It is very common for owners to bring their dogs to the clinic for a "skin rash" that most of the times is blamed on flea bites or various allergies, having wasted time applying topical creams and other products for dermatitis! As a result, the diagnosis of Ehrlichiosis in these cases is delayed!!!
"Petechiae" are usually first noticed by the owner on those hairless parts of the body (belly , inside of ear flaps) where the skin is more exposed. Shaving other parts of the body in order to reveal more "petechiae", supports the clinical diagnosis.
REMEMBER: DO NOT WASTE VALUABLE TIME ASSUMING THAT YOUR DOG SUFFERS FROM SOMEKIND OF SKIN DISEASE BEFORE YOU SEEK VETERINARY HELP! IF SOMETHING AS SERIOUS AS EHRLICHIOSIS IS GOING ON, THEN TIME IS PRECIOUS!
(Photo: from clinic's archive)
(Photo: from clinic's archive)
VERY IMPORTANT REMINDER:
"RAT POISONING" CAN MANIFEST ON A DOG WITH THE SAME SKIN HEMORRHAGES AS "EHRLICHIOSIS".
DO NOT MISS TO REPORT TO YOUR VET ANY SUSPISCIONS YOU MIGHT HAVE ABOUT YOUR DOG HAVING INGESTED SUCH POISONS!
If your dog is presented with the above described clinical signs of bleeding, the Vet will explain that there is need for further investigation, blood tests and possibly preventative treatment for 2 or 3 possible causes. It is not uncommon for owners to get confused and upset or blame the Vet for being incompetent when a clear, definitive diagnosis is not reached on a first approach. But it is true that the clinical presentation of a "bleeding" dog is followed by a long list of possible causes and there is definitely no rule to impose that only 1 possible cause should be involved! In other words, no one can rule out the possibility of more than 2 pathological conditions occuring at the same time!
In these cases, time is precious! The Vet is asked to cover the wasted by the delayed presentation of the animal time, and this is the reason why preventative treatment for multiple causes might be administered, until the specific blood test results reveal the true cause of the animal's condition.
But personally, even if in a case of a bleeding dog I had clinical evidence of Ehrlichiosis or Leishmaniosis, I would still be wondering if the dog had also access to rat poisons! Even more if the owner would not rule out that possibility!!! What I am trying to say is that:
The clinical presentation of a "bleeding" dog is a true nightmare for the clinican! Things would be a lot better if animals "spoke" but they don't, so owners and Vets should work together in order to achieve a successful outcome.
3. Lymphadenomegaly (enlarged lymph nodes): Again, a non specific clinical signs that manifests in many other pathological conditions.
4. Splenomegaly (enlarged Spleen): Again, a clinical sign very often found in cases of Leishmaniosis too.
5.Ocular changes: Anterior uveitis, Subretinal hemorrhage and Retinal detachment leading to acute blindness.
6.Neurological signs: as a result of inflammation and bleeding in the neurological system that can lead to epileptic fits.
7.Polyarthritis-Polymyositis.
8.Glomerulonephritis (kidney disease).
I would give special empasis to Polyarthritis, as it is a clinical sign that would not normally refer to the disease of Ehrlichiosis in a dog that is just "lame"!!!!!
In quite a few cases presented in our clinic, the only clinical finding was one or more swollen joints and the main complain by the owner was an intermittent lameness as a result of bleeding inside the joints or arthritis caused by the deposition of immune complexes due to Ehrlichiosis.
(Photo. from the clinic's archive)
-HOW IS DIAGNOSIS OF EHRLICHIOSIS REACHED?
Diagnosis of Ehrlichiosis is a true challenge due to its different phases, multiple clinical manifestations and different species of causative agent.
Suspicion of the disease is based on some or all of the previously mentioned clinical signs, together with a compatible history (tick infestation, travelling to or living in an endemic region) as well as typical hematological and biochemical abnormalities present. Confirmation of the disease though, requires specialized blood tests.
If your dog is suspicious of Ehrlichiosis, your Vet will first of all perform a GENERAL blood test called CBC (complete blood count). This is the kind of blood test that detects , if present, the first hematological abnormalities. The very first changes in the numbers of certain blood cells "might" show up in this blood test. Complicated and difficult to understand words and terms such as: Pancytopenia, Anemia, Neutropenia, Thrombocytopenia will initially cause you a true "headache", but your Vet will help you understand what exactly is going on inside your dog's body!
So,common hematological abnormalities in a dog that suffers from Ehrlichiosis are:
1.Thrombocytopenia (reduction in the absolute number of platelets).
This is the most consistent hematologic abnormality in both the acute and chronic stages of Ehrlichiosis, but it is very important to underline that:
a. It is NOT a "pathognomonic" sign (means, not specific for this disease only ), and
b. It is NOT always present.
Reduced platelets can be found in a number of other pathological conditions and this is very important to bear in mind when diagnosing Ehrlichiosis in a dog with reduced platelet numbers. On the other hand, normal platelet numbers DOES NOT preclude the diagnosis of Ehrlichiosis in an otherwise suspiscious dog! (not a common finding in the suclinical phase of the disease).
2. Anemia (reduction in the total numbers of RED blood cells). Anemia can be mild at the early stages of the disease or moderate to severe and NON regenerative in the CHRONIC phase, when bone marrow suppression has settled.
3 .Pancytopenia (reduction in the numbers of all white blood cells): is a common hematological finding in dogs suffering from the CHRONIC severe form of the disease due to the bone marrow suppression. Leukemia should be included in the differential diagnosis of these animals.
4.Lymphocytosis.
SEROLOGICAL TESTING: this is a procedure (a blood test ), that detects specific antibodies against Ehrlichia spp.and it is the most well known and reliable method for diagnosing this disease in dogs. This test should be done within 1 month (the latest), after the confirmed presence of tick(s) on a dog and of course in every dog that shows relevant clinical signs or as a preventative diagnostic test in dogs that live in or travel to endemic areas.
Testing for this disease only a few days after you find a tick on your dog may lead to "false" negative results, as the incubation period of Ehrlichiosis is between 8-20 days.
One month after the tick infestation (provided the dog is clinically healthy and not showing any signs of illness!!!), is a safe period of time that allows more accurate diagnosis and prevents the progression of the disease in a dog that got infected.
A well informed and responsible owner who seeks Veterinary advice on time, is the most important factor in the successful management of Ehrlichiosis.
♦REMEMBER!
♦ Performing blood tests soon after the detection or more precisely after the attachment of ticks on a dog ( there is a good chance that the tick had been there for long before the owner noticed it!!!!) might lead to FALSE negative results.
♦ One month is a long enough and safe period of time in order to diagnose the disease and avoid its progression, provided the animal is clinically healthy.
♦ A successful diagnosis requires a well educated owner and an experienced and dedicated Vet.
♦ Preventative administration of drugs against Ehrlichiosis is NOT recommended in cases that have not been confirmed***
*** I would possibly exclude those cases where more than one ticks where found on a dog in an endemic area. These ticks were probably here and multiplying on the dog's body long before the owner noticed them! Unfortunately, the chances of disease transmission to a dog that suffered a heavy tick infestation are HIGH, in endemic areas. For these animals only, I would accept the preventative administration of appropriate medication, under strict Veterinary supervision and while awaiting the specific blood test results!!!! (Considering that clinical improvement can be achieved within 24-48hours after the initiation of specific treatment).
If you find a tick on your dog and the first blood test a month later is negative, you can request another blood test 2-3 months later in order to obtain a more accurate result. If you have travelled or stayed in endemic for this disease areas, it would be advisable to perform this test, regardless of the presence or not of ticks on your dog.
For the serological testing there are "speed" tests available as well as specialized laboratories that perform specific techniques for the diagnosis of this disease.
!!!Cases where the serological testing for Ehrlichia antibodies was negative despite the clinical evidence of disease as well as the compatible hematological abnormalities, are frequently reported in clinical practice. These cases are usually the result of infection by different species of Ehrlichia (other than E.canis), not detected by the specific serological test. Dogs can get infected by Ehrlichia chaffeensis, Ehrlichi ewingii, Anaplasma platys, Babesia canis etc. These cases are the most difficult to deal with as far as the diagnosis (which requires several different types of blood tests) and the Owner-Vet communication. Not reaching a definitive diagnosis, despite the extensive diagnostic approach is frustrating for both owner and Vet!!!
REMEMBER:
Ticks can transmit to your dog different species of bacteria that belong to the same group of Ehrlichia or the greater family of Rickettsiaceae. Serologic tests usually detect antibodies against certain species of Ehrlichia. If the serologic test result is negative for Ehrlichia but your Vet has the suspiscion and holds evidence of your dog suffering from a "TICK BORNE DISEASE", you should trust his knowledge and expertise and follow the advice given.
A more specific diagnostic method not very common in practice - PCR- which detects the DNA of the responsible for the infection species is even more specific and it can give positive results in 4-10 days after inoculation. PCR can confirm the diagnosis of canine Ehrlichiosis and identify the infecting Ehrlichia species.
Not all dogs found positive for Ehrlichiosis will eventually develop the disease. A positive antibody titer may indicate active infection, latent infection or previous exposure to Ehrlichia, but it is the clinical presentation of the animal together with other hematological abnormalities that will determine the course of treatment necessary.
Practice has proved though, that due to the severity of the disease the administration of drugs is absolutely necessary for every animal found positive on a first approach, even if it hasn't developed the relevant clinical signs yet.
Ehrlichiosis might be an incidental finding during the diagnostic investigation of a dog that suffers from different pathological causes at the same time. In these cases, treatment might require the combination of many different drugs.
It is quite common for owners to request a repeat serological test (antibody titer) soon after the end of treatment. This is not a routine practice in our clinic for the following reason: There is no point in repeating the serological test for Ehrlichiosis right after the end of the treatment, simply because a reduction in the antibody titer requires 6-9 months. Many dogs that have returned to normal, still have a high titer of antibodies against Ehrlichiosis months after the initial diagnosis and treatment.
Treatment monitoring is mandatory and includes follow up blood tests: CBC (complete blood count) is the blood test of choice, where the animal's Hematocrit, Platelet and Total White blood cell numbers levels are monitored. Improvement in these parameteres together with the clinical presentation of the animal confirm the successful outcome of the treatment.
Infrequently, a dog maintains a high antibody titer or a hematologic abnormality such as Thrombocytopenia persists for a very long time after the completion of treatment for Ehrlichiosis disappointing the owner who despite the great effort in treating his animal does not receive the "good" news from the blood tests! It is unclear whether these dogs are chronically infected with Ehrlichia or infected with other pathogens (eg. LEISHMANIOSIS!!!) or if the persistent hematologic abnormalities are mediated through altered immunoregulation induced by the organism. In any case, the possibility of concurrent infections (especially with LEISHMANIOSIS ) should be investigated and specific treatment should be administered in case of positive results. In cases of chronically infected animals, ancillary treatment should be considered!
ΒΙOCHEMICAL BLOOD TESTS: a common finding in these tests is the increase in the levels of liver enzymes (ALT,ALP) which quite often leads to the wrong assumption that a liver disease is the underlying cause (especially when specific serological testing for Ehrlichiosis has not been done).
Another important diagnostic tool to differentiate the infecting E. spp and to determine if the treatment has effectively eliminated the infection is PCR. In dogs with persistently high E. canis antibody titers , PCR testing is indicated, when antibiotics are not being administered.
-IS TREATMENT FOR EHRLICHIOSIS SUCCESSFUL?
YES IT CAN BE!
Complete cure in cases of Ehrlichiosis is possible, provided the diagnosis is reached on time , BEFORE the disease progresses and affects the bone marrow.
The treatment of Ehrlichiosis consists of antirickettsial agents and supportive care depending on the clinical status of the animal.
DOXYCYCLINE is the drug of choice for the treatment of Ehrlichiosis and it is administered by mouth for a period of 28 days at least!
Clinical improvement of cases where the diagnosis was reached early enough (acute or early stages of chronic phase), is noticed really soon and sometimes even 24-48 hours after the administration of the first dose!
UNDER NO CIRCUMSTANCES SHOULD YOU INTERRUPT THE COURSE OF TREATMENT, EVEN IF CLINICAL IMPROVEMENT SHOWS VERY SOON!
If the treatment is interrupted too soon, a flare up of the disease is almost guaranteed!
IMIDOCARB, (Veterinary product: IMIZOL),is an antiprotozoal drug has also been used in cases of resistant E.Canis infections. This drug is only administered by a Veterinary surgeon via an injection under the skin and close observation of the patient is absolutely necessary for a few hours after the administration.
IMIDOCARB persists in the tissues for up to 1 month after one dose and it is the prolonged exposure of E.canis to the drug that leads to a successful treatment.
The clinical condition of an animal that suffers from Ehrlichiosis is going to determine the type and duration of treatment.
Treating the CHRONIC phase of Ehrlichiosis is challenging, as dogs usually do not respond to treatment with antibiotics alone. A BLOOD TRANSFUSION is sometimes mandatory in animals that have entered the CHRONIC phase of the disease and have developed serious anemia due to bone marrow suppression. Regeneration of bone marrow may require up to 120 days following treatment.
The use of glucocorticoids is also acceptable in certain cases of Ehrlichiosis where either due to the clinical presentation of the animal or due to certain hematological changes, a definitive diagnosis is not possible and the possibility of Autoimmune Thrombocytopenia exists. In other cases, where bleeding has occured or Ehrlichiosis has caused other pathological conditions such as : polyarthritis, polymyositis, vasculitis, meningitis etc, the use of glucocorticoids can be an acceptable choice.
YOU WILL NOT FIND TREATMENT RECOMMENDATIONS OR SPECIFIC DRUG THERAPIES AND DOSES FOR EHRLICHIOSIS (OR ANY OTHER DISEASE) ON THIS WEBSITE. DRUG ADMINISTRATION SHOULD BE APPLIED TO CONFIRMED CASES AND UNDER THE CLOSE SUPPERVISION OF A VETERINARY SURGEON. DRUG DOSES AND DURATION OF TREATMENT DEPENDS A LOT ON THE CLINICAL PRESENTATION OF THE INDIVIDUAL PATIENT AND IS CALCULATED BASED ON THE PATIENT'S BODY WEIGHT.
-TREATMENT FOLLOW UP!
Close monitoring of a dog under treatment for Ehrlichiosis is absolutely necessary as it is quite common for the infection to persist for a very long time, despite the administration of the appropriate medication.
A CBC (complete blood count) should be repeated 10-15 days after the initiation of treatment. Among the first hematological indications that the animal is responding to the treatment, is the increase in the numbers of platelets. The same blood test should be repeated 1-3 months after the end of the treatment, as the risk of disease flare up is always present.
Proving that E.canis bacteria has been eliminated from the dog's system after the end of a treatment course, is difficult and almost impossible. Repeating serological tests for the detection of specific antibodies against the disease is of no clinical importance, as the time required for the antibody titers to decrease is quite long and it does not coincide witht the clinical improvement of the patient! In other words, a dog that has returned to normal clinical condition and the hematological parameters have been normalized, can still have high antibody titers against E.canis.
IMPORTANT MEMO: One should always bear in mind that reinfection of an animal that lives in or travels to endemic areas is always possible!!!
CONCLUSION
Prognosis of Ehrlichiosis is good for those cases where early diagnosis was achieved and appropriate treatment was administered for the recommended length of time. More precisely the SHORT TERM prognosis in these cases is good.
♦What is the meaning of SHORT TERM prognosis?
SHORT TERM prognosis means that an animal that suffers from Ehrlichiosis and receives the appropriate treatment early enough in the disease course, can manifest a dramatic clinical improvement even within the first 24-48 hours. This is mostly true for the animals that were diagnosed in the acute or mild-chronic phase disease. For those chronically and severly infected animals though, periods of up to a year may be necessary for the complete hematologic recovery despite the rapid clinical improvement. This means that your dog might have a perfectly healthy clinical appearance but your Vet still be concerned and advise frequent blood testing of the animal, based on the hematologic results that might still be abnormal.
The LONG TERM prognosis for Ehrlichiosis is variable and depends on many factors, the most important being: EARLY DIAGNOSIS!
Another equally important factor is the early diagnosis and treatment of concurrent infections. The most important and frequent one, is LEISHMANIOSIS (in the endemic for the disease areas).
It is my opinion that for every animal diagnosed with the disease of Ehrlichiosis, a specific diagnostic test for the disease of Leishmaniosis should be performed as well! The concurrent infection is a very common phenomenon in our country where both diseases are endemic.
From my clinical experience, the most common causes of death for animals that suffered from Ehrlichiosis are :
1.Delayed diagnosis or incomplete treatment both leading to the developement of the most severe chronic phase of the disease and in most of these cases the actual cause of death are uncontrollable hemorrhages.
2.Concurrent serious infections (most commonly LEISHMANIOSIS) that did not get diagnosed on time and as a result they manifested in their most severe form and further compromised the immune system of the affected animal.
-CAN EHRLICHIOSIS BE PREVENTED?
Part of this disease's prevention measures is the frequent checks for the presence of ectoparasites on your pet, as well as annual blood testing against the disease(whether you live in an endemic area or travel with your pet to endemic areas!). Most of all, you should feel free to seek veterinary advice and trust valid sources of information.
A vaccine against Ehrlichiosis is not currently available (2016). Prevention is based exclusively on the avoidance of tick bites through thorough examination of you pet's skin, use of reliable ectoparaciticide products as well as avoidance of exposure to environments with high parasitic burden.
Preventative use of antibiotics in animals that were either attacked by ticks or were exposed to high risk areas, , is often reported as an appropriate method especially in places such us breeding kennels, boarding kennels or animal shelters.
My personal opinion is that the unreasonable use of antibiotics either by the owners of dogs or the Veterinary professionals, is an abuse and will very soon lead to a dead end with the developement of highly resistant microbes/parasites. The use of antibiotics should be practiced in those confirmed cases of Ehrlichiosis under Veterinary guidance. The preventative use of antibiotics though can be an appropriate approach in those cases where tick control measures are of limited affectiveness (kennels, stray dogs shelthers etc) or high tick infestations are found on a dog. In these cases, where infection by Ehrlichia spp. is very possible, the preventative administration of specific antibiotics under the supervision of a Veterinary surgeon is accepted.
The most effective way of preventing this disease (or more precisely, avoiding a poor outcome ), is the frequent blood testing of dogs that live in or travel to endemic areas. Blood testing your dog once a year, during the winter months, as well as requesting immediate clinical Veterinary examination of an animal that was attacked by ticks, are the best ways of obtaining good results.
REMEMBER:
COMPLETE CURE OF EHRLICHIOSIS IS NOT FOLLOWED BY LIFELONG PROTECTION AGAINST THE DISEASE VIA ANTIBODIES.
In other words, the animal that contracted the disease, fell ill and got treated and cured, WILL NOT BE PROTECTED in the future via specific ANTIBODIES against Ehrlichiosis. The same animal, can get infected again and again in the future if attacked by contaminated ticks.
The role of humoral immunity is of minor importance in fighting Ehrlichiosis. The main role remains in the Cellular immunity.
Do not underestimate your pet's short term illness blaiming it on the summer heat! (ESPECIALLY IN AREAS WHERE THE DISEASE IS ENDEMIC!) Every dog that displays 1 or 2 days of unusual behavior or sudden illeness, should be examined by a Vet.
REMEMBER:
♦In order for the tick to transmit the disease to a dog, it has to contract the disease first via blood sucking from another diseased dog. The tick itself, cannot transfer the disease to its' discendants. Therefore, if you have more than one dogs and the disease has been diagnosed in one of them, you should perform all the appropriate diagnostic tests to your other dogs too.
♦Always select reliable and clean boarding kennels for your pets, where strict hygiene measures are applied and perform routine ectoparasite treatment to your pet prior to entering these spaces!
♦There is a wide range of available paraciticide products in the veterinary market, such as Sprays, Spot ons, Tablets etc. You should seek veterinary advice on the selection of the most appropriate product for your pet and you should definitely not trust cheap and not liscensed products which promise fighting off all types of ectoparasites!!!!
♦Tick control measures are very important but may not always provide an effective means to prevent infection.
DO NOT ADMINISTER ANTIBIOTICS TO YOUR PETS UNDER THE GUIDANCE OF OTHER DOG OWNERS WHO HAPPEN TO CARE FOR AN ANIMAL THAT SUFERS FROM EHRLICHIOSIS.
YOU SHOULD NOT ADMINISTER ANY TREATMENT AGAINST EHRLICHIOSIS TO YOUR PET IN A PREVENTATIVE MANNER, WITHOUT VETERINARY ADVICE AND WITHOUT HAVING CONFIRMED THE DISEASE VIA SPECIALIZED BLOOD TESTS. DRUGS, REMEDIES OR PRODUCTS OF ANY KIND AGAINST EHRLICHIOSIS SHOULD NOT BE ADMINISTERED TO YOUR PET BASED ON THE SUSPISCION OF DISEASE TRANSMISSION DUE TO THE PRESENCE OF TICKS ON YOUR DOG'S SKIN OR THE CONFIRMATION OF THE DISEASE IN ANOTHER PET UNDER YOUR CARE OR THE PRESENCE OF DISEASED DOGS IN YOUR AREA.
-WHAT ARE THE DANGERS OF HANDLING A DOG WITH EHRLICHIOSIS FOR THE OWNER?
Most Ehrlichia species are capable of infecting humans, but dogs play a seemingly minor role in the acquisition of human infections.
LIVING WITH A DOG THAT SUFFERS FROM EHRLICHIOSIS AND CARING FOR IT, DOES NOT INVOLVE THE RISK OF CONTRACTING THE DISEASE!
Human Ehrlichiosis is caused by different species of Ehrlichia( E.chaffeensis,Ehrlichia ewingii,Ehrlichia muris-like), capable of causing serious disease manifestations such as: meningoencephalitis, acute renal failure, acute respiratory failure.The disease can be transmitted to humans (as in dogs), via tick bites. There are different types of ticks attacking dogs and humans around the world and many different diseases transmitted by them. In certain areas of the planet, the risk of disease transmission from ticks to humans is high and for this reason special travelling advice is given to those visiting high risk areas.(Some useful advice can be found on this website )
Disease transmission is NOT possible between dog and human. The dog though, plays an important role in the carriage of ticks and therefore in the disease transmission to humans directly from the ticks. Humans are usually exposed to the same environmental risks as their pets!
In human medicine, there is an increasing interest in the study of possible disease transmission, between humans via blood transfusions.
REMEMBER:
♦You run the same risk of getting attacked by ticks as your dog, since you are living together and walking together every day!
♦Handling ticks while removing them from your dog's skin, can potentially expose you to the risk of contracting the disease.
♦Never remove ticks from your dog's body in bare hands!
REFERENCES.
1.Greene: Infectious Diseases of the dog and cat.
2.Dwight D. Bowman: Georgis' Parasitology for veterinarians.
3.http://www.cvbd.org/en/tick-borne-diseases/ehrlichiosis/pathogenesis-and-transmission/
4.http://www.cdc.gov/ehrlichiosis/
6.Treatment of Canine Ehrlichiosis: World small animal veterinary association, world congress proceedings, 2011. Edward B. Breitschwerdt, DVM, DACVIM.
7. A.Rick Alleman, DVM, PhD, DACVP, DABVP (Canine and Feline Practice), CEO and Manager of Lighthouse Veterinary Consultants, Alachea, FL, USA: More Than Just E. canis: The Increasingly complicated story of Ehrlichiosis. ABVP 2015.
8.ST.J.ETTINGER, ED.C.FELDMAN: CANINE EHRLICHIOSIS.Textbook of Veterinary Internal Medicine. pp 632-634
9.CVBD DIGEST World Forum: Canine Ehrlichiosis-from Acute Infection to Chronic Disease. No 7 2010. www.cvbd.org