The first I heard of this disease was when I took a Babe into my vet for a health check just a couple days after I got her.  I had been waiting for her for a long time and she had been ill prior to my getting her.  Even though I was told she had been tested heart worm negative I had my vet recheck her just for my piece of mind.  She had come from an area in the country with very little heart worms and had not even been tested for it until I asked about it.  This time my paranoia paid off because in addition to testing for heart worms my vet also tested for C.E. And she was absolutely, no doubt about it, positive!

We had spent quite a while talking and working with Babe before this test was done.  There had been so many things which had not been thought out well before I got her and she had been treated incorrectly for months with a variety of drugs.  Treating the symptoms of the problem instead of considering that they were symptoms of a bigger problem.  I understand that this is the single most common problem with healing with C.E.  There is a tendency to not put the problems together in one package, all caused by one disease.

This disease is carried by the brown dog tick and is more common in areas with a larger tick population/infestation.  Keeping and maintaining tick free kennels will help but doesn't assure an animal will not be infected, but it helps.  There are 2 phases of the disease, acute and chronic.  The acute variety usually shows within the first 3 weeks or so of being bitten.  Some symptoms are fever, runny eyes/nose, swollen lymph nodes among others.  This variety responds well to treatment  in a short amount of time...usually going into remission and a return to health.

Chronic C.E. however usually can wait several months before signs start to show. Prolonged high temp, dehydration, no appetite, inability to keep food down, weight loss and lots of others as well. This phase of the disease, with proper medication, may have a good life.  Both varieties require antibiotics in the form of tetracycline. Up until recently this has been the only drug available in the US for treatment but just recently another one which has been used abroad has come here...I am unclear at this point if it is simply for research or wither we can actually get it for our babies. I will keep you all posted as L learn more about that aspect. Unfortunately the chronic form of the disease can kill.

Since this disease affects the immune system you really need to be careful about booster vaccinations.  I have had to make the decision to not give her a 6 month Parvo booster at this time until she is stronger and we can learn more about what the consequences might be. Right now my little Babette has good days and bad days.  She gets her medication 3 times a day and is also taking antibiotics in an olive oil based eye drops in both eyes for ulcers she has on both corneas...  We have 2 weeks to go on that and then will go in for testing.

This disease is out there.  It has been reported in every state and worldwide as well.  You cannot get it from an infected dog but you can from an infected tick. If you have a dog with the problem,  would like to share your story or have more links I would be delighted to have the info to add here!

An Overview of Canine Ehrlichiosis

Lauren Bockino, B.S.; Paula M. Krimer, DVM, DVSc; Kenneth S. Latimer, DVM, PhD; and Perry J. Bain, DVM, PhD

Class of 2003, Ross University, School of Veterinary Medicine, St. Kitts, West Indies (Bockino) and Department of Pathology (Krimer, Latimer, Bain), College of Veterinary Medicine, University of Georgia, Athens, GA 30602-7388

Introduction

The Ehrlichiae are a group of small, gram-negative, pleiomorphic, obligate intracellular cocci that infect different blood cells in various animal species and in humans. There has recently been a reclassification of the family Anaplasmataceae to which the Ehrlichiae belong.⁸ According to this new classification there are two leukotrophic diseases in dogs that are caused by bacteria in the genus Ehrlichia, namely, Canine Monocytic Ehrlichiosis (caused mainly by Ehrlichia canis) and Canine Granulocytic Ehrlichiosis (caused by Ehrlichia ewingii). It should be noted that cross-reactivity and co-infection is common among the ehrlichiae.⁷ Classically, canine ehrlichiosis presents as a rather non-specific multisystemic disorder with the primary complaints being depression, lethargy, mild weight loss, vomiting, diarrhea, and anorexia, with or without hemorrhagic tendencies. Furthermore, patients may present with uveitis and/or retinal petechiae, polymyositis, polyarthritis, and central nervous system signs.² Hematologic abnormalities most commonly associated with canine ehrlichiosis include nonregenerative anemia and thrombocytopenia. Serum chemistry commonly reveals hyperglobulinemia (monoclonal or polyclonal gammopathy), hypoalbuminemia, and low albumin-globulin ratio.⁵

Canine Monocytic Ehrlichiosis (Ehrlichia canis)

Canine Monocytic Ehrlichiosis (CME), caused by E. canis, is an acute to chronic disease of monocytes, and is the ehrlichial disease most extensively studied. This organism is primarily transmitted by Rhipicephalus sanguineus, the brown dog tick. It is seen mostly in the southeastern and southwestern United States, although it is recognized in all states and worldwide. Amblyomma and Dermacentor ticks have also been implicated in transmission of this disease.³ Dogs may present with variable clinical signs, but thrombocytopenia with bleeding tendencies is the most consistent presenting complaint in dogs in both the acute and chronic stages of the disease.¹ During the acute stage, splenomegaly and lymphadenomegaly are common. In the chronic stage, widespread hemorrhage and increased mononuclear cell infiltration of organs may also be evident. Hematologic changes include nonregenerative anemia, thrombocytopenia, and leukopenia. Pancytopenia may occur as a result of hypoplasia of all bone marrow precursor cells, more commonly in the severe chronic phase.⁴ Some dogs may develop a secondary immune-mediated hemolytic anemia (IMHA) and have an acute hemolytic crisis, and, thus, a positive direct antiglobulin (Coombs') test.¹

Canine Granulocytic Ehrlichiosis (Ehrlichia ewingii)

Canine Granulocytic Ehrlichiosis (CGE) caused by Ehrlichia ewingii, is a disease of neutrophils and, rarely, eosinophils. CGE classically presents with mild signs including fever, lethargy, anorexia, weight loss, vomiting, diarrhea, severe but transient thrombocytopenia, and transient mild nonregenerative anemia with ineffective erythropoeisis. Commonly, the major presenting clinical signs associated with E. ewingii include lameness and joint swelling due to polyarthritis. This form of ehrlichiosis is generally seen in the southern and mideastern United States.^1,4 Ticks including Ixodes pacificus, Dermacentor variabilis, Rhipicephalus sanguineus, Amblyomma americanum (especially in North Carolina), and Ixodes scapularis (damminni) have been implicated as vectors.^3,6

Pathogenesis of Ehrlichiosis

The pathogenesis of infection with E. canis is the most extensively studied; therefore this discussion will focus on this particular species.

Infection occurs through salivary secretions of the tick at the attachment site during ingestion of a blood meal or through blood transfusions. If the adult Rhipicephalus sanguineus engorges on the dog during the acute stage, it can transmit the disease to other dogs for at least 155 days following detachment.¹ Transmission by Rhipicephalus sanguineus is transstadial: the tick acquires the bacteria by feeding on an infected dog in either the larvae or nymph form and the tick transmits the disease to another dog as either the nymph or adult form. The life cycle of Ehrlichia is not yet completely understood but it is thought that it occurs in three intracellular forms. The initial bodies are small spherical structures (1-2 micrometers in diameter) which are believed to develop into larger multiple membrane-bound units known as morulae. The morulae are inclusions within the cytoplasm of the leukocyte as seen in Figure 1. This morula is thought to then dissociate into small granules called elementary bodies.

Figure 1. Ehrlichia canis seen in a membrane-bound inclusions (morulae) within the cytoplasm of a monocyte (buffy coat smear, Wright stain).

After an incubation period of 8-20 days, the acute phase of infection occurs which lasts 2-4 weeks. At this time, the organism multiplies within circulating mononuclear cells and the mononuclear phagocytes within the liver, spleen, and lymph nodes. The infected cells are then transported in circulation to the rest of the body, with a predilection for the lungs, kidneys and meninges. Cells infected with ehrlichia adhere to the vascular endothelium and induce a vasculitis and subendothelial tissue infection. This subsequently leads to platelet consumption, sequestration, and destruction that results in the thrombocytopenia seen during this acute phase. Variable leukocyte counts and anemia may also develop progressively during this stage.¹ After 6-9 weeks, dogs will either eliminate the parasite (if immunocompetent) or develop a parasitemia in which clinical signs absent to mild to severe. This stage is also characterized by variable persistence of thrombocytopenia, leukopenia, and anemia. Dogs that cannot mount an effective immune response will become chronically infected.¹

Diagnosis

Definitive diagnosis of CME requires visualization of morula within monocytes on cytology, detection of E. canis serum antibodies with the indirect immunofluorescence antibody test (IFA), polymerase chain reaction (PCR) amplification, and/or gel blotting (Western immunoblotting).

On cytology, ehrlichiae stain dark blue to purple with Romanowsky stain. The morulae are well-defined, round to oval, eosinophilic to basophilic bodies found in host membrane-lined vacuoles within the cytoplasm of the mononuclear cells.¹

In dogs experimentally infected with E. canis, the IFA test has detected serum antibodies as early as 7 days after initial infection, although some dogs do not become seropositive until 28 days post-infection. If ehrlichiosis is highly suspected clinically in a seronegative dog, serology should be repeated in 2-3 weeks. In the past, titers of IgG antibodies of >1:80 have been considered diagnostic,¹ but the most recent research has indicated that titers <1:80 should be deemed suspect and serology should be repeated in 2-3 weeks or a PCR or Western immunoblotting should be considered. A diagnosis should be made and treatment instituted when clinical signs and clinicopathological abnormalities consistent with canine ehrlichiosis are found.²

There are a few potential downfalls of using the IFA test for the diagnosis of E. canis infection. One major concern exists in endemic areas with dogs that are chronically infected and have a positive titer, but are otherwise healthy or show non-specific clinical signs. In these dogs, a positive antibody titer does indicate past exposure to E. canis, does not prove that ehrlichiosis is necessarily an active infection or the cause of the presenting clinical signs. In dogs with non-specific clinical signs, a repeat IFA test after 1 or 2 weeks may be beneficial to differentiate between primary E. canis infection and another secondary disease. Antibody titers to E. canis should increase with active infection. Furthermore, one must consider co-infection with multiple tick-borne diseases caused by agents such as other Ehrlichiae, Rickettsia species, Bartonella species, and Babesia canis. Disease caused by any of these agents may be clinically, hematologically, and serologically indistinguishable from each other. In addition, the immunodominant proteins of E. canis have been shown to serologically cross-react with those of E. chaffeensis (the agent that causes Human Monocytic Ehrlichiosis). Studies have shown that serologic testing by IFA could not consistently distinguish between infections of these two species. Interpretation of E. canis serology should include the consideration of the disease process, cross-reactivities with other ehrlichial species, the possibility of multiple tick-borne infections, and persistent IFA antibody titers post-treatment. Antibody titers be used to gauge the success or failure of treatment of CME. Treatment success should be based on remission of clinical signs, a decline in E. canis antibody titers and a concurrent decrease in gammaglobulin concentrations.⁷

PCR amplification is also a sensitive method for the detection of acute E. canis although there are currently several potential limitations. It is recommended that this method be used in addition to serology for the initial diagnosis of ehrlichiosis, not instead of it.²

The diagnosis of CGE differs from that of CME as E. ewingii has not yet been cultivated in an in vitro system, therefore antigens have not been available for comparative serological testing. Diagnosis of CGE requires visualization of morula within neutrophils in peripheral blood (Figure 2), joint effusions, and PCR or Western immunoblot.³ In a study using Western immunoblots, sera from dogs that were experimentally infected with E. ewingii were tested on E. canis antigens. Although there were no reactions with the dominant E. canis antigens, the sera produced binding patterns similar to those of anti-E. canis sera with high molecular proteins. This also may help with the diagnosis of CGE.⁷

Figure 2. A segmented neutrophil from a dog that contains morula of a granulocytic species of Ehrlichia, most commonly Ehrlichia ewingii (blood smear, Wright stain).

 

Treatment and Prevention

The mainstay of prevention of canine ehrlichiosis is tick control. The drug of choice for treatment for all forms of ehrlichiosis is doxycycline for at least one month. There should be dramatic clinical improvement within 24-48 hours following initiation of treatment in dogs with acute-phase or mild chronic-phase disease. During this time, platelet counts begin to increase and should be normal within 14 days after initiation of treatment.^1,2 Polyarthritis associated with E. ewingii may be self-limiting.³ Previous infection does not confer lifelong immunity, and dogs can become reinfected with the same or other ehrlichial species after re-exposure to infective ticks.

 

References

1. Ettinger SJ, Feldman EC: Textbook of Veterinary Internal Medicine: Diseases of the Dog and Cat, vol. 1, 5^th ed. W.B. Saunders Co., Philadelphia, 2000, pp. 402-406.

2. Neer TM, Breitschwerdt EB, Greene RT, Lappin, MR: Consensus statement on ehrlichial disease of small animals from the Infectious Disease Study Group of the ACVIM. J Vet Intern Med 16:309-315, 2002.

3. Goldman EE, Breitschwerdt EB, Grindem CB, Hegarty BC, Walls JJ, Dumler JS: Granulocytic ehrlichiosis in dogs from North Carolina and Virginia. J Vet Intern Med 12:61-70, 1998.

4. Neer TM: Canine monocytic and granulocytic ehrlichiosis. In: Greene CE (ed): Infectious Diseases of the Dog and Cat, 2^nd ed. W.B. Saunders Co., Philadelphia, 1998, pp.139-147.

5. Varela F, Font X, Valladares JE, Alberola J: Thrombocytopenia and light-chain proteinuria in a dog naturally infected with Ehrlichia canis. J Vet Intern Med 11:309-311, 1997.

6. Wolf L, McPherson T, Harrison B, Engber B, Anderson A, Whitt P: Prevalence of Ehrlichia ewingii in Amblyomma americanum in North Carolina. J Clin Microbiol 38:2795, 2000.

7. Waner T, Harrus S, Jongejan F, Bark H, Keysary A, Cornelissen A: Significance of serological testing for ehrlichial diseases in dogs with special emphasis on the diagnosis of canine monocytic ehrlichiosis caused by Ehrlichia canis. Vet Parasitol 95:1-15, 2001.

8. Ehrlichia Research Laboratory, College of Veterinary Medicine, The Ohio State University, Columbus, OH

The watercolor "Barbara's Dogs" by Tom Martin, New Moon Illuminations, is used with permission of the artist.

Clinical Name: Ehrlichiosis, Ehrlichia
Overview

Dogs get ehrlichiosis from the brown dog tick, which passes an Ehrlichia organism into the bloodstream when it bites. There are three stages of ehrlichiosis, each varying in severity. The acute stage, occurring several weeks after infection and lasting for up to a month, can lead to fever and disorders of the blood. The second stage, called the sub clinical phase, has no outward signs and can last for up to five years. If the infected dog’s immune system is unable to eliminate the Ehrlichia organism, the third and most serious stage of infection, the chronic phase, will commence. Lameness, neurological and ophthalmic disorders, kidney disease, and anemia and other blood disorders can result. Chronic ehrlichiosis can be fatal.

Antibiotics, administered for an extended period of time, are effective at eliminating the infection. Dogs with severe cases of chronic ehrlichiosis cannot be cured, but supportive care and treatment of diseases secondary to the infection, such as anemia, can help stabilize the dog.

Clinical Signs and Symptoms

The acute stage of the disease, occurring most often in the spring and summer, begins one to three weeks after infection and lasts for two to four weeks. Clinical signs include a fever, petechiae, bleeding disorders, and vasculitis. There are no outward signs of the sub clinical phase, which can last for up to five years. Clinical signs of the chronic phase include pale gums due to anemia, thrombocytopenia, vasculitis, lymphadenopathy, respiratory dyspnea, coughing, polyuria, polydipsia, lameness, ophthalmic diseases such as retinal hemorrhage and anterior uveitis, and neurological disease.

Diagnosis

Diagnosis is achieved most commonly by serologic testing of the blood for the presence of antibodies against the Ehrlichia organism. During the acute phase of infection, however, the test can be falsely negative because the body will not have had time to make antibodies to the infection. Thus, the test will need to be repeated if the first result is negative. In addition, blood tests will show abnormalities in the numbers of red cells, white cells, and platelets. Uncommonly, a diagnosis can be made by looking under a microscope at a blood smear for the presence of the Ehrlichia organism, which sometimes can be seen within a white blood cell.

Description

Ehrlichiosis is a tick-borne disease of dogs that is caused by an organism called Ehrlichia. There are several species of Ehrlichia, but the one that most commonly affects dogs and causes the most severe clinical signs is Ehrlichia canis. The brown dog tick, or Rhipicephalus sanguineous, that passes the Ehrlichia to the dog is prevalent throughout most of the United States, but most cases tend to occur in the Southwest and Gulf Coast regions where there is a high concentration of the tick.

There are three stages of the Ehrlichia canis infection: acute, sub clinical, and chronic. Approximately one to three weeks following the infection, clinical signs of the acute phase begin and typically last for two to four weeks. The sub clinical phase, which does not produce outward clinical signs, lasts for up to five years. If the dog’s immune system is unable to eliminate the organism during this stage, the chronic phase will occur and may last for years, depending on the severity of the infection. 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.

Transmission or Cause

The Ehrlichia organism is passed to the dog through the saliva of a tick called Rhipicephalus sanguineous. These ticks are prevalent throughout most of the United States, but most cases of infection tend to occur in the Southwest and Gulf Coast regions.

Treatment

Supportive care must be provided to animals that have clinical signs. Subcutaneous or intravenous fluids are given to dehydrated animals, and severely anemic dogs may require a blood transfusion. Treatment for ehrlichiosis involves the use of antibiotics such as doxycycline for a period of at least six to eight weeks; response to the drugs may take one month. In addition, steroids may be indicated in severe cases in which the level of platelets is so low that the condition is life threatening.

Prognosis

The prognosis is good for dogs with acute ehrlichiosis. For dogs that have reached the chronic stage of the disease, the prognosis is guarded. When bone marrow suppression occurs and there are low levels of blood cells, the animal may not respond to treatment.

Prevention

Prevent tick infestation by avoiding tick-infested areas. In addition, there are many methods for controlling fleas, including medicated shampoos, dips, sprays, the Preventic® collar, or Frontline®. If tick control is not feasible, tetracycline at a lower dose can be given daily for 200 days during the tick season in endemic regions.

Article republished here with permission from VetCentric.com
Copyright(c) 2000 by VetCentric.com

Ehrlichiosis

by Holly Frisby, DVM

Drs. Foster & Smith, Inc.
Veterinary Services Department

Canine ehrlichiosis is a disease of dogs and wild canids (e.g., wolves) and is found worldwide. Canine ehrlichiosis is also known by other names such as "tracker dog disease", "tropical canine pancytopenia", "canine hemorrhagic fever", and "canine typhus". It affected a large number of military dogs in the war in Vietnam.

What causes ehrlichiosis?

Ehrlichiosis can be caused by several organisms including Ehrlichia canis, E. equip, E. platys, E. ewingii, and possibly others. The Ehrlichia organisms are what we call rickettsia which on the evolutionary scale are between bacteria and viruses.

How is Ehrlichia transmitted?

Ehrlichia is transmitted by the brown dog tick, Rhipicephalus sanguineus. The immature form of the tick feeds on an animal infected with Ehrlichia. When these immature forms or a mature form of the tick feeds on another animal, the Ehrlichia is passed on to that animal. The Ehrlichia can remain alive in the developing tick for up to 5 months. This means a tick could become infected in the fall, and infect a dog the following spring.

Because the disease is transmitted by the brown dog tick, it can occur wherever brown dog ticks are found. Almost every state in the United States has reported a case of ehrlichiosis.

What are the symptoms of ehrlichiosis?

Ehrlichiosis can have three phases. Signs of the acute phase of the disease usually develop 1-3 weeks after the bite of the infected tick. The acute phase of the disease generally lasts 2-4 weeks. The Ehrlichia enter certain cells of the body and reproduce inside of them. These cells are found in the lymph nodes, spleen, liver, blood, and bone marrow. As a result of the infection the lymph nodes, liver and spleen are often enlarged. Anemia, fever, depression, lethargy, loss of appetite, shortness of breath, joint pain and stiffness, and bruises are often seen.

In the sub clinical phase the animal may show only slight anemia. During this phase the dog either eliminates the Ehrlichia from the body or the infection may progress to the chronic phase.

The chronic phase generally develops 1-4 months after the tick bite and can be either mild or severe. Weight loss, anemia, neurological signs, bleeding, inflammation of the eye, edema (fluid accumulation) in the hind legs and fever may be seen. Blood tests show that one or all of the different blood cell types are decreased. One cell type, the lymphocyte may increase and be abnormal in appearance. This can sometimes be confused with certain types of leukemia. If a dog becomes chronically infected, the disease can keep coming back, especially during periods of stress.

A decrease in the number of platelets (platelets help the blood clot) in the blood is the most common laboratory finding in all phases of the disease. Changes in the protein levels in the blood are common. The most common protein, albumin, is decreased and other types of protein called "globulins" are increased.

Since one tick could be infected with and transmit more than one disease (e.g., haemobartonellosis or asbestosis), it is not all that uncommon to see a dog infected with more than one of these diseases at a time which generally causes more severe symptoms.

How is ehrlichiosis diagnosed?

A highly accurate blood test which tests for the dog's antibodies (proteins produced to fight off the infection) to Ehrlichia is available. It is called the indirect immunofluorescent antibody (IFA) test. The antibodies may not be detected in the early phase of the disease since it takes some time for the body to make them. As the disease progresses, the antibody level will rise significantly. Often two tests will be done 2 weeks apart and the results compared. Dogs with an active infection will show a significant rise in the amount of antibody present.

A newer test called the ELISA test is becoming more available and the test can be run in your veterinarian's laboratory. This test also determines the amount of antibodies present.

The antibodies can last for one or more years after the infection, but they do not make the dog immune to ehrlichiosis - the dog could get reinfected.

Sometimes the organism can be seen inside cells on a blood smear. To find them, a small drop of blood is spread over a microscope slide, stained and examined under the microscope. The organism can only be found in the blood stream for about 3 days during the acute phase of the disease. So this method of diagnosis could miss some cases of the disease.

How is ehrlichiosis treated?

The antibiotics tetracycline or doxycycline are used. Treatment is for 2-3 weeks. Some dogs will need blood transfusions or intravenous fluids depending on the severity of the disease. Generally the prognosis during the acute phase is good if the animal is properly treated. Dogs who go on to the chronic phase have a poorer prognosis. German shepherds and Doberman pinschers tend to have a more severe chronic form of the disease.

The drug imidocarb dipropionate is sometimes used in conjunction with the antibiotics. It is given as an injection, but may not be available in all areas.

Some of the damage caused by Ehrlichia may be due to the dog's own immune response to the organism. For this reason, high doses of corticosteroids (e.g., prednisolone) are often given during the early phase of the disease.

How can I prevent ehrlichiosis in my pet?

Tick control is the main way to prevent ehrlichiosis. Products which repel and kill ticks such as Biospot for Dogs are excellent choices. Tick collars containing the active ingredient amitraz (Preventic collars) are also used, sometimes in conjunction with Biospot in those areas with high tick infestations. If a large number of cases of ehrlichiosis are diagnosed in an area, some veterinarians recommend placing dogs on low doses of tetracycline or doxycycline during the tick season.

There is no vaccine for ehrlichiosis.

Can people get ehrlichiosis?

Yes. The common symptoms in people include fever, chills, headache, and muscle aches. Other less common symptoms include nausea, loss of appetite, weight loss, abdominal pain, cough, diarrhea and change in mental status.

People do NOT get infected directly from a dog, but through a tick bite. Human ehrlichiosis may be spread by a different tick than the brown dog tick. Research suggests the Lone Star tick may be involved. Also, the Ehrlichia species most often implicated in human infections is E. chaffeensis.

References

Couto, DG. Rickettsial Diseases. In Birchard, SJ; Sherding, RG (eds): Saunders Manual of Small Animal Practice. WB Saunders Co., Philadelphia PA; 1994;124-5..

Harrus, S; Bark, H; Waner, T. Canine monocytic ehrlichiosis: An update. Compendium of Continuing Education for the Veterinary Practitioner 1997;19 (4) :431-444.

Olson, JG. Ehrlichiosis. In: Zoonoses updates from the Journal of the American Veterinary Medical Association. American Veterinary Medical Association, Schaumburg IL; 1995:74-75.

First I want to thank Jan and Bob for giving me the opportunity to make some remarks and to congratulate them for undertaking such heavy and well executed responsibility to address this important issue. Their basic premise was to reach the owner/breeder and also to establish dialogue with the veterinary clinicians and scientists outside the vet's office. I think they have achieved both. The owners and breeders will gather tremendous information from this article in a language they will understand since there is a minimum of technical jargon to cloud their reading enthusiasm. The veterinarian and scientist will get the challenging message that the 21st century clients have modern tools to watch everything we do and publish and they are looking for a practical product for their pet.... at times regardless of how much it will cost. The clients are also prepared to work with us to the extent possible and when they question our training they are not vet bashing but trying to develop a dialogue.

The authors are right in indicating that diseases have no borders. Today the definition of a tropical disease could not have been more nebulous and blurred! That is why we have task forces in USA and Europe to deal with "Emerging diseases" which show up suddenly and unexpectedly. In some ways ehrlichiosis meets that definition.

This raises the issue of training in tropical medicine. The authors' point is well taken that veterinary curricula are facing the challenge to accommodate the problems of newly emerging diseases, such as ehrlichiosis.

Extra attention needs to be paid to this segment if future veterinarians are going to be prepared for diseases that just emerge here or encountered in missions overseas. It is gratifying to know that there is a Society of Tropical Veterinary Medicine and "Intervet" which expose our veterinary community to so- called foreign diseases. The USDA at Plum Island along with the CDC are examples of establishments that have enormous resources to educate all of us on these issues.

Bob and Jan bring up the issue of the complexity of ehrlichiosis. In fact the disease is more of a syndrome. Readers will appreciate this from articles such as that written by David Huxsoll who has so neatly categorized the stages of the disease. The spectrum of syndromes and disease entities imitated by ehrlichiosis are incredible, emphasizing the need to carefully rule out ehrlichiosis for common infectious diseases.

The warning signs may certainly be subtle. Can one rule out ehrlichiosis by the IFA test and should we treat all animals which are IFA positive? First, a positive IFA test simply means "current or previous exposure" ........treatment or recovery does not guarantee a negative IFA.

Any patient positive in the IFA and presenting with signs consistent with ehrlichiosis should definitely be treated. Indeed empirical treatment is reasonable if in the clinician's assessment waiting for the IFA results could endanger the patient. IFA could certainly be negative during the very early phase of the disease even when severe signs are evident.

Therefore, in the writer's opinion a clinical assessment may supercede the IFA status. A positive IFA test excludes a dog from being a blood donor and membership of a breeding stock for the fear of transmitting the disease and every effort should be made to research into methods of terminating the carrier state.

Provided the treatment is prescribed and monitored by a veterinarian, it seems less risky to treat IFA positive animals resident in a non-endemic area than to risk a severe disease. In an endemic area, however, treatment on the basis of the IFA test per se cannot be justified since the patient will again be exposed and the synergistic advantage between antibodies and the cellular immune system may be of value in fighting the new infection. In other words, in areas where the diseases are common practically every dog has been exposed and treatment can only be justified on the basis of the clinical disease.

The relatively low endemicity in many parts of North America means that supervised treatment of early diagnosed( by IFA or PCR) cases is worthwhile to prevent costly potential worsening of the patient's condition or even death, as mentioned by Bob and Jan. They have shared with us their private experiences in which intervention helped some cases and when the problem was recognized too late the patient could not be saved. It must be emphasized, however that empirical treatment with antibiotics must be carefully evaluated and monitored to avoid abuse of these important compounds.

The other issue raised is "early diagnosis". The PCR test is showing promise and perhaps in future it will be available routinely. Because the test is DNA-based, it offers the most specific and sensitive detection method which confirms that the patient is definitely infected and treatment would be indicated without any doubt. Finally, we must join the authors in a crusade to find alternative drugs to doxcyline and tetracyline in case we encounter resistance to these drugs or we are treating mixed infections ( e.g. ehrlichiosis and babesiosis). A case in point is Imizol® a well tested drug used in may parts of the world but not legally available for dog treatment in USA. (Since the article was written in 1996 , unfortunately, little has changed. However, one important change is the fact that Imizol is now available and your vet should be able to easily obtain it. This drug is given by injection in a series, normally, of two shots two weeks apart. - Bob Wilson 1/14/2000). Compassionate users of Imizol® have reported impressive results in cats and dogs suffering from ehrlichiosis and we should continue research to facilitate approval by the FDA. The ultimate goal should however be the development of a vaccine for this disease complex and for that we need to work with the breeder, the owner, industry and academia. This mission is noble according to the wishes of friends such as Pajti, Jake, Bear, Saucy and many others born in the Hendricks and Mair families.

For those searching for additional reading please search under the following scientists: Ewing, S; Huxsoll, D; Breschwerdt, E; Dawson, J; Lewis, G E; Holland, C J; Ristic, M R; Dutta; Rikihisa, Y; Madigan, J; Dumler; Bakken; Nyindo; Roult; Long, M; Goetz; Palmer, G; Walker, D; and many other scientists.

Ibulaimu Kakoma,DVM PHD
Urbana IL.
January, 1996

Treatment with proper antibiotics can be quite dramatic in these cases, whereas treating an ehrlichiosis patient with steroids or drugs other than the tetracycline family will almost certainly lead to tragedy.

THE TRIP TO THE VET

Today's veterinarian will also acknowledge that today's pets travel far and wide with their owners. As a result, the diseases and vectors are no longer limited to specific regions. Ticks thrive in cold as well as warm climates and where the tick goes, so goes the ehrlichiosis.

EHRLICHIA - WHAT IS IT?

Ehrlichiosis is related to Rocky Mountain Spotted Fever and shares similar signs, though rarely does a victim of ehrlichiosis display the rash that is associated with RMSF. Lyme disease also shares some of the same signs, but technically is in a separate category. Lyme disease is caused by a spirochete (a spiral shaped bacteria) and although it is transmitted by ticks, as are most of the rocketries, Lyme disease is sensitive to a wider range of antibiotics, and Lyme disease has never been linked to fatalities as are many of the rickettsias. The rickettsial group is unique in that it's members share some traits of a virus, and some traits of a bacteria, but they are classified with bacteria.

While doxycycline is frequently used to treat Lyme disease other drugs have been used. Amoxicillin is a recent trend in the treatment of Lyme disease but has no effect whatsoever on ehrlichiosis. As both Lyme disease and ehrlichiosis share some signs a misdiagnosis of ehrlichia as Lyme disease could prove fatal to both dogs and humans if not treated with the proper drug.

Rickettsias actually parasitize the white blood cells, which is why they are so devastating to their victims. Essentially, they cripple the immune system by inhibiting the basic function of the bone marrow - that of making new cells to replace old and dying cells.

Once a human or animal is stricken with ehrlichiosis, white cells die off faster than the bone marrow can replace them. These dead cells migrate primarily to the spleen which enlarges as a result. Frantically, the bone marrow works to form new, healthy cells. In its haste, it sends out immature cells which do not work efficiently. Quite often these immature cells are almost indistinguishable from those seen in leukemic patients. Advanced Ehrlichiosis is, in fact, often misdiagnosed as leukemia or lymphosarcoma.

To complicate things further, ongoing research suggests that chronic ehrlichiosis may lead to various cancers, especially leukemia and lymphosarcoma. There is speculation that it may predispose animals to other forms of cancer as well. Because of its effect on the nervous system, ehrlichiosis is also sometimes misdiagnosed as brain cancer. It does, in fact, affect many dogs neurologically and can cause seizures, problems with coordination, changes in temperament, or obsessive-compulsive behavior (such as repeated licking or other repetitive behaviors.)

Causes of death by ehrlichia are usually due to internal hemorrhage including hemorrhage into the brain, severe autoimmune disease, multiple secondary infections due to a compromised immune system or complete failure of one or more internal organs such as heart, liver, spleen, etc.

HOW IS IT TRANSMITTED?

It should also be noted that it has been fatal in humans whereas Lyme disease has yet to claim its first victim.

THE STAGES OF EHRLICHIOSIS

Once the chronic stage is reached, the rickettsial organism has taken up residence within the bone marrow. At this point the damage done is often irreversible. It is not unusual for dogs in this final stage to suffer massive internal hemorrhage, or succumb to sudden stroke, heart attack, renal failure, splenic rupture or liver failure, resulting in death. A peculiarity about the disease is - these dogs often do not look or act as though they are in a terminal stage of disease until their final hour.

DETECTION OF EHRLICHIA

Regardless of the what the titer is, any positive should be considered indicative of infection and treated quickly and aggressively. A dog with a negative titer who has signs should still be treated, then re-tested at a later date.

Although E. canis and E. risticii appear to be the most common species to infect dogs, other species are out there which won't be detected if the laboratory is testing strictly for E. canis or E. risticii. (Another reason to treat the signs even if the titer test is negative.) CBC panels have been used but they are too non specific to be reliable. There are many cases where a dog's CBC has been "within normal limits" yet the dog died of ehrlichiosis!

CBC Panel abnormalities are often so borderline, they may be overlooked by the vet as inconsequential. An example could be a dog who appears to have sufficient platelets, yet is showing signs of internal hemorrhage (blood in urine, bruising on mucosal surfaces, coughing, bloodshot eyes etc.) This can happen because the platelets have lost their ability to function normally - they can actually lose their adhesiveness which hinders their ability to form a normal blood clot.

When abnormalities are seen in a CBC Panel, they may include a reduction in platelets, mild anemia, high WBC (usually in new infections), low WBC (usually in chronic cases), high sedimentation rate (due to dead cells outnumbering healthy cells), high alkaline/phosphatase ratio, and other slight abnormalities. Kidney function tests may show high BUN and creatinine. In these cases, the diet should be altered to lessen the strain on the kidneys.

The following laboratories are experienced in running the IFA test for various species of ehrlichia, including E. risticii. In some laboratories discounts may be available, either when testing for several species of ehrlichial infection in the same dog (a "rickettsial panel") or if multiple dogs (such as in a breeding kennel) are tested at the same time ("bulk testing"). Be sure to inquire about any discounts before blood is sent.

Blood must be spun down to separate the serum component which is then shipped via overnight mail in a cold pack. Direct any questions about this procedure to the laboratory where you are sending the sample.

It is recommended that ehrlichiosis be ruled out before accepting these diagnoses as a definitive cause of the illness or condition. Ehrlichiosis is known to be prevalent in racing greyhounds; there is no question amongst veterinarians who have dealt with the disease that it must be taken seriously and aggressively treated. Testing is simple and definitive; a positive titer at any level needs to be treated. Very good results can be obtained with readily available, inexpensive treatment of a 7 to 8 week course of tetracycline or doxycycline at the correct dosage. (For further information contact: Susan Netboy at (800) 446-8637) Contents Copyright (c) 1995, Greyhound Friends For Life. Last Modified: August 15, 1995.

TREATMENT OF EHRLICHIOSIS

We strongly advise against waiting for a positive result before treating with doxycycline. Vets should also be cautioned about the use of steroids in a dog who may have ehrlichiosis. If Lyme disease is the suspect then treat with doxycycline. Although some chronically-infected dogs may need steroid treatment, this should always be done in conjunction with doxycycline treatment and only as a last resort measure. In cases where the vet feels more than one disease may be involved, ehrlichiosis should be given the first priority.

In acute cases there is usually a dramatic response to treatment. A case in point involved a Border Terrier owned by one of the authors. He presented with signs consistent with renal failure, and renal failure is not usually treated with doxycycline. However, the owner was aware that the dog had been exposed, and the signs had come on quite suddenly. There was also apparent (though slight) enlargement of the spleen and liver. The vet then reluctantly agreed to treat with doxycycline along with other supportive therapy.

When the test results came back 48 hours later, the vet was alarmed at the apparent indication of chronic renal failure. However, re-examination and testing of the patient showed dramatic improvement - 2 days on doxycycline had brought kidney function back within the normal range, the heart rate had returned to normal, and dehydration was no longer evident. Subsequent IFA titer tests showed the dog was indeed positive for both E. canisand E. risticii. Due to the decision to treat immediately, this dog is still alive, enjoys excellent health, and has normal kidney function at age 7 1/2 years. This also makes the drug a diagnostic tool as well as treatment. If the signs disappear with treatment it is almost a virtual certainty that the dog has been infected and blood tests should be run to make the confirmation.

Most cases have shown a good response to treatment with the tetracycline family of antibiotics. Doxycycline is the preferred drug as it has less potential side effects and better penetration of certain bacteria (Merck). Inoculations as well as injectable antibiotics should not be administered to a dog suspect for ehrlichial infection, as reactions have been reported, some of which proved fatal to the patient (the immune system is already taxed due to the action of the disease.)

Another drug, Imizol®, has also proven very effective, but unfortunately it is not readily available in the US and is still considered experimental. (Since the article was written in 1996 , unfortunately, little has changed. However, one important change is the fact that Imizol is now available and your vet should be able to easily obtain it. This drug is given by injection in a series, normally, of two shots two weeks apart. - Bob Wilson 1/14/2000).

The suggested treatment with doxycycline has been 5 to 10mg per day per Kg. (according to the Merck Manual.) Some dogs have been treated at a rate of 20 mg per kg body weight per day (or 200 mg for the typical 22 pound dog, divided into two daily doses given 12 hours apart) with excellent results. Most cases have shown that the higher dosage is more effective, but its use will be dictated by the animals tolerance. It should be administered for at least a 6 week period. Due to the high dosage Merck also suggests vitamin supplementation with vitamins B and K due to the reduction in the animals ability to synthesize those vitamins in the large intestine. In some cases wrapping the tablet in a piece of bread or adding to rice will facilitate administering the drug as well as helping to prevent nausea which may occur in some animals on the high dosage.

CONCLUSION

For those who read this and can influence pharmaceutical companies to develop a vaccine as has been done for Lyme disease, we will consider our mission complete.

ACKNOWLEDGEMENTS