What is hemoplasmosis?
Also known as feline infectious anaemia (FIA), hemoplasmosis (formerly known as hemobartonellosis) is an infection caused by an unusual group of bacteria known as 'mycoplasmas'. These bacteria have no cell wall and most of them live within or on the host cell. In the case of hemoplasmosis, the bacteria live on the walls of red blood cells.
Until recently, the organism responsible for hemoplasmosis was known as Hemobartonella felis, since reclassification, it has been discovered that there are in fact two species involved.
Collectively they are known as Feline Hemoplasmas, Hemotropic Mycoplasmas or Mycoplasma Hemofelis.
M. hemofelis can cause illness in healthy cats, however Mycoplasma hemominutum appears to be more of an opportunistic parasite, typically infecting cats with an underlying condition such as FIV or FeLV.
Feline hemoplasmas attach themselves the wall of red blood cells. The body's immune system tries to destroy these parasites but in the process also destroys the affected red blood cells, leading to anemia. It is not possible to culture Feline Haemoplasmas because they cannot survive outside the host cell.
The disease can affect cats of any age, although it is most commonly seen in male cats between 1-3 years old.
How do cats become infected?
Symptoms usually appear 3-5 weeks after transmission. The natural mode of transmission is thought to be via fleas and tick bites where the parasite passes infected blood from one cat to another. Bites and scratches from infected cats may also spread the infection.
Infected queens can pass on the infection to their kittens although it's not entirely known if it is in utero, during the birth process or via the milk.
It is possible for cats to become infected during a blood transfusion although blood is routinely screened, so this should not occur.
What are the symptoms of hemoplasmosis?
Symptoms vary depending on the number of red blood cells infected, the stage of the parasitic infection, the health status of the cat and the rapidity of infection. Clinical signs usually include those associated with anemia and may include:
- Loss of appetite
- Pale mucous membranes (ie: pale gums)
- Weight loss
- Jaundice (yellowing of the gums, whites of the eyes, and skin)
- Enlarged lymph nodes
- Enlarged spleen
Untreated, FIA can cause death.
How is hemoplasmosis diagnosed?
There are two methods to test for hemoplasmosis.
Stained blood smear: A thin film of blood is stained and studied under a microscope for the presence of organisms on the red blood cells. However, this can result in a false negative as the infection seems to come about in cycles, so several blood samples taken over a period of days may be required.
Polymerase Chain Reaction (PCR): This is a test which detects the organism in the blood. It greatly amplifies the DNA of the organism, even in small amounts.
How is hemoplasmosis treated?
Treatment of hemoplasmosis includes both supportive care and antibiotics.
Antibiotics oxytetracycline or doxycycline.
Treatment with a glucocorticoid such as prednisolone may also be prescribed to diminish the immune-mediated component of the disease process.
Severely anaemic cats may require blood transfusions.
Cats having breathing difficulties may require oxygen.
Recovered cats can still carry the organism in small numbers in their blood, although they will show no clinical signs. They may have a relapse in the future, especially under times of stress or they may remain free of the disease for life.
How do I prevent hemoplasmosis in my cat?
Proper flea and tick control on your cat, including keeping the environment free of parasites.