Tick Fever

Cattle ticks transmit organisms that cause tick fever, commonly known as ‘red water’ in cattle. Tick fever can result in loss of condition, mortalities, abortions and reduction in bull fertility. There are three types of tick fever organisms, Babesia bovis, Babesia bigemina and Anaplasma marginale.

Cattle that have been exposed to cattle tick at a young age build up lifelong immunity to these organisms, however, cattle from the tick free area that have never been exposed to cattle ticks will not have immunity. Cattle from the tick free area will require tick fever vaccination before moving in to a cattle tick infected area.

Clinical signs of tick fever

Signs of tick fever include:

• weakness
• depression
• sudden development of fever - temperature around 41° C (106° F). The fever stage usually lasts about a week.
• loss of appetite and rumination (chewing of cud) ceases
• The animal isolates itself from the herd; it is disinclined to move and stands with the head lowered and ears drooping.
• The coat may appear ruffled, breathing becomes rapid and jerky and heart beat is accelerated.
• The mucous membranes of the eyes, nose and mouth become yellow due to anaemia and jaundice.
• The animal exhibits incoordination of the hindquarters, muscle shivering and a tendency to charge when disturbed.
• Emaciation occurs.
• The animal passes red coloured urine.

Note: Most deaths occur in the third week, but may occur any time after 24 hours of infection. Death may be precipitated by exertion or excitement.

Despite the common name 'red water', red urine is only occasionally present and is seen late in the course of the disease. Cattle with Babesia bovis infections may be quite sick even if they do not show signs of anaemia and red urine.

Diagnosing tick fever

Tick fever is difficult to diagnose based on clinical signs alone. The best way to diagnose tick fever is through laboratory examination of blood smears.

Risk factors for tick fever

Breed

British and other Bos taurus cattle breeds are more susceptible to tick fever caused by Babesia organisms than Brahman (Bos indicus) breeds. Cross breeds (Bos taurus x Bos indicus) have intermediate susceptibility which will vary depending on the percentage of each breed type.

Both Bos indicus and Bos taurus breeds are highly susceptible to disease caused by Anaplasma marginale.

Age

There is a strong link between age and resistance with most outbreaks occurring in animals 18 to 36 months of age. Calves exposed to tick fever organisms between three to nine months of age rarely show clinical signs and develop a solid, long-lasting immunity.

Exposure

Cattle born and raised in areas where cattle ticks are endemic can develop natural immunity through exposure to ticks infected with tick fever.

However, exposure of calves to ticks infected with tick fever (and subsequent development of protective immunity) can be highly unpredictable. Exposure is influenced by factors such as breed, season and tick-control strategies.

Cattle from tick free areas should not be introduced into cattle tick infected areas without first receiving a tick fever vaccination. Ideally cattle will be vaccinated prior to nine months of age so they are set for later in life. The second best option is to ensure that cattle have been vaccinated at least two months prior to departure from tick free area to ensure that immunity has developed. If cattle need to be moved shortly after vaccination they should be moved either before day seven, or between days 21 to 30 after vaccination. This provides the less stress during the animals’ peak reaction times.

Treatment

There are two types of tick fever vaccination, chilled trivalent vaccine and frozen trivalent vaccine. The more commonly used chilled trivalent vaccine is a live vaccine that contains strains of three tick fever parasites (Babesia bovis, Babesia bigemina and Anaplasma marginale). The frozen vaccine, also known as Combavac 3 in 1, is used in remote areas where it is not possible to get chilled vaccine delivered by the following day, or for properties where vaccine is needed to be kept on hand.

If used as directed, one dose of the live vaccines should provide lifelong immunity against all three parasites. The organisms in the vaccine multiply once injected in to the cattle, as would occur in a real life infection. The organisms in the vaccine are less infectious, allowing for immunity to develop without mortalities or serious production losses.

Ordering the vaccine

You can order vaccine directly from the Tick Fever Centre, through your local veterinarian or rural agency.

Chilled vaccine: Chilled vaccine is only produced on Tuesdays and Thursdays. Orders are not accepted on the day of dispatch but must be in by 4pm the day prior (Monday or Thursday) to production.

Frozen vaccine: Frozen vaccine is dispatched on Fridays, so orders must be received by 4pm on Wednesday.

References

Business Queensland 2016, Tick Fever Vaccines for cattle, Queensland Government, accessed 1^st February 2019 <https://www.business.qld.gov.au/industries/farms-fishing-forestry/agriculture/livestock/cattle/tick-fever-vaccines >

Department of Primary Industry and Resources 2016, AgNote: Tick Fevers of Cattle, Northern Territory Governments, accessed 19^th February 2019
<https://dpir.nt.gov.au/__data/assets/pdf_file/0010/233488/713.pdf>