Updated: Jun 22, 2021
What is Nairobi Bleeding Disease (Ehrlichiosis)?
Nairobi Bleeding Disease (Ehrlichiosis) is a tick-borne infectious disease of dogs. The organism responsible for this disease is a rickettsial organism (Ehrlichia canis), usually carried by the brown dog tick (Rhipicephalus sanguineous).
Rickettsial organisms are specialized type of bacteria that live only inside other cells. The disease seems to be particularly severe in German Shepherd Dogs and Doberman Pinschers.
How is a dog infected with Ehrlichia?
The brown dog tick is the main carrier of the Ehrlichia organism in nature. Other tick species, have also been shown to transmit the disease in dogs and may carry other subspecies of Ehrlichia.
What are the signs of Nairobi Bleeding Disease (ehrlichiosis)?
Clinical signs of ehrlichiosis are divided into three stages:
Acute (early disease),
Sub-clinical (no outward signs of disease), and
Clinical or chronic (long-standing infection).
The Acute Phase
The infected dogs may have:-
Swollen lymph nodes,
Bleeding disorders (spontaneous haemorrhage or bleeding), and
Occasionally, neurological disturbances (they may seem unsteady or develop meningitis).
This stage may last two to four weeks and some dogs may eliminate the infection or head into the sub-clinical phase.
The sub-clinical phase
In this stage of infection, the organism is present but causes no outward signs of disease. The dog may develop changes observed at the laboratory level, yet have no apparent signs of illness. The sub-clinical phase is the worst phase because there are no clinical signs and the disease goes undetected. A blood sample is the only thing that may show that a dog is infected during this phase, or when the dog shows prolonged bleeding from a puncture site. Dogs that are sub-clinical may eliminate the organisms or may progress to the next stage, clinical ehrlichiosis.
Clinical ehrlichiosis phase
This phase occurs when the immune system is not unable to eliminate the organism. The dogs then develop a host of problems:
Eye problems (including haemorrhage into the eyes or blindness),
Neurological problems, and
The bone marrow (site of blood cell production) fails, the dog becomes unable to manufacture any of the blood cells necessary to sustain life (red blood cells, white blood cells, and platelets).
How is Nairobi Bleeding Disease (ehrlichiosis) diagnosed?
It is difficult to diagnose infected dogs during the very early stages of infection. The immune system usually takes two to three weeks to respond to the presence of the organism and develop antibodies.
The tests used to diagnose ehrlichiosis are:-
ELISA (enzyme-linked immunosorbent assay) test
IFA (indirect fluorescent antibody) test
Baseline blood tests including a complete blood cell count (haematology) and biochemistry are also done. A low platelet count (called thrombocytopenia), anaemia (low red blood cell counts), and/or high levels of the protein globulin in the blood may be found.
Rarely, the organism itself may be seen in blood smears or in samples of cells taken from the lymph nodes, spleen, and lungs.
A newer test, a PCR assay, is becoming available in certain veterinary laboratories.
How is Nairobi Bleeding Disease (ehrlichiosis) treated?
Dogs experiencing severe anaemia or bleeding problems may require a blood transfusion. However, this does nothing to treat the underlying disease.
Antibiotics, such as doxycycline, are quite effective. A long course of treatment, generally three weeks, is needed. This is the treatment of choice as it is easily accessible and generally well tolerated.
Alternatively, imidocarb (Imizol) can be used.
Some supportive medications such as steroids, eg. prednisolone, may be needed depending on the clinical state of the patient and blood parameters.
How is Nairobi Bleeding Disease (ehrlichiosis) prevented?
Managing the dog's environment against ticks and applying flea and tick preventives are the most effective means of prevention.
Topical options include Advantix and Frontline Plus (given once per month) or Bravecto (given once every 3 months).
Oral chewable options include Nexgard (given monthly), Simparica (given monthly), or Bravecto (given every 3 months).
Can Nairobi Bleeding Disease (ehrlichiosis) be transmitted to humans?
No. However, humans can get canine ehrlichiosis from tick bites. The disease is only transmitted through the bites of ticks. Therefore, even though the disease is not transmitted directly from dogs to humans, infected dogs serve as sentinels, or warnings to indicate the presence of infected ticks in the area.
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Companion vector-borne diseases: www.cvbd.org/static/documents/digest/CVBD_Easy-to-digest_no_7_ehrlichiosis.pdf
European Scientific Counsel Companion Animal Parasites: www.esccap.org/uploads/docs/znkh6j1d_0775_ESCCAP_Guideline_GL5_v8_1p.pdf