Includes Anaplasmosis, babesiosis

Tick fevers are notifiable diseases in NSW. Submission of appropriate specimens accompanied by a Specimen Submission Form requesting exclusion of tick fever is suitable notification. There are no laboratory fees for tests taken to exclude tick fever.

Diagnosis

Clinical signs, demonstration of organisms in blood or organ smears.

Tick fever should be suspected in animals showing haemoglobinuria, elevated temperature, jaundice and anaemia. Babesia bovis (argentina) infections often cause nervous symptoms, followed by coma and death. Splenomegaly at necropsy is characteristic.  The animal and its herd mates should be examined for ticks. 

See Ticks.

If cattle ticks are found the index of suspicion increases. Ticks are however not always found in cases of tick fever in NSW.

Specimens required

Live animal

1. Thin blood films prepared from jugular or tail vein blood and from tail tip capillary blood for parasitology. See below for instruction on taking tail tip capillary blood. The smears should be air dried, avoiding exposure to heat, formalin  or direct sunlight. (see Specimens for haematology).
2. Unstained thick blood smears for haematology from the same sites as above.
3. Blood collected into EDTA, submitted chilled for parasitology and haematology.
4. Full clotted blood tube (10 ml) or 2ml serum, submitted chilled for serology.
5. Urine sample, submitted chilled for bacteriology and urinalysis.

Dead animal

1. Blood films, air dried for parasitology (Try expressing a drop of blood from an ear vein).
2. Impression smears from the kidney, heart, liver and brain for parasitology.
3. Fresh brain or brain squash preparation from the grey matter of the cerebral cortex. Prepare by crushing a match head sized sample of the cerebral grey matter between 2 slides and spreading lightly in a wavy motion.
4. Sections of kidney, heart, liver, brain and spleen, submitted chilled for bacteriology and parasitology.
5. Sections of kidney, heart, liver, spleen and brain (prepare smears first), submitted in buffered formalin for histopathology.

Collecting blood from the tail tip:

A similar technique is illustrated on the Queensland Department of Primary Industries (www.dpi.qld.gov.au) web site. 

1. Hold the tip of the tail in one hand and fold the brush back so that the tail tip is exposed
2. Trim the hairs from the tail tip and rub vigorously with the palm of the free hand to clean the skin of debris and increase blood flow
3. Nick the skin of the tip of the tail with sharp scissors or prick it with a hypodermic needle (you are attempting to collect blood from the capillaries in the skin)
4. Maintain your grip on the tail and the brush while lowering the tip to allow the blood to flow
5. Raise the tail tip again and look for a drop of blood on the skin over the incision. Repeat steps 3-5, ‘milking’ the tail if necessary.
6. Collect the first drop of blood in the centre of a glass microscope slide. The corner of another slide, a swab stick or a bacterial loop can be used to transfer the blood. Prepare a thin blood film (see Specimens for haematology)
7. Collect a second drop of blood near the end of a second glass microscope slide.  Prepare a thick blood film (see below)

Preparation of thick blood films

Spread the drop of blood with the corner of another clean slide or with a bacteriological loop

1. Start in the centre of the drop and using a circular motion expand the diameter of the drop until the smear is just thin enough to allow the hands of a watch to be read when viewed through the blood film (it may be approx 1cm in diameter at this stage)
2. Set the slide aside to dry in a cool clean shady spot. Do not expose it to the heat of the sun. Do not allow it to become dusty. Do not expose it to formalin fumes.