Tick fever Tick fever is a cattle disease caused by any ne f the fllwing bld parasites: Babesia bvis Babesia bigemina Anaplasma marginale These parasites are all transmitted by the cattle tick (Bphilus micrplus). Disease caused by Babesia bvis r Babesia bigemina is called babesisis, ften referred t as 'red water'. Disease caused by Anaplasma marginale is called anaplasmsis. Babesia bvis is the mst imprtant parasite, causing mre than 80% f utbreaks f tick fever in Queensland each year. Tick fever is highly prevalent in ur area and will kill nn-immune cattle if they are nt vaccinated. Clinical signs f tick fever Signs f tick fever include: weakness depressin lss f appetite These signs are mainly due t the assciated fever and red bld cell destructin (causing anaemia). Despite the cmmn name 'red water', red urine is nly ccasinally present and late in the curse f the disease. Other clinical signs may include jaundice and neurlgical signs. Cattle with Babesia bvis infectins may be quite sick even in the absence f anaemia and red urine. Diagnsing tick fever It is difficult t diagnse tick fever based n clinical signs alne. The best way t diagnse tick fever is t send bld smears t a labratry fr examinatin. Risk factrs fr tick fever Breed British, Eurpean and ther Bs taurus cattle breeds are mre susceptible t tick fever caused by Babesia rganisms than Brahman and Bs indicus breeds. Crss breeds (Bs taurus x Bs indicus) have intermediate susceptibility determined by the percentage f each breed type. stablerandhwlett.cm.au
All breeds, including Bs indicus breeds, are highly susceptible t disease caused by Anaplasma marginale. Age There is a strng link between age and resistance. Mst utbreaks ccur in animals 18 t 36 mnths f age. Calves expsed t tick fever rganisms between 3 t 9 mnths f age rarely shw clinical signs and develp a slid, lng-lasting immunity. Expsure Cattle brn and raised in areas where cattle ticks are endemic can develp natural immunity thrugh expsure t ticks infected with tick fever. Hwever this immunity can disappear quite quickly if the tick challenge is cmpletely eliminated. We have witnessed several utbreaks f tick fever subsequent t excessive use f pur n prducts. Tick fever vaccine Chilled tick fever vaccine is an excellent vaccine that prvides strng, durable immunity frm a single sht. Shelf life and strage Chilled vaccine is supplied ready t use. It is stred and transprted at 2-8 C (d nt freeze) and must be used within 4 days f manufacture. Dsage and administratin Using a vaccinatr gun, inject a single 2mL dse either subcutaneusly (under the skin) r intramuscularly (int the muscle). Animals' respnse t vaccinatin Animals underg mild reactins as the immune system is stimulated t prduce lng-term (usually lifelng) prtectin against the disease. Develpment f immunity 3-4 weeks after vaccinatin fr bth species f Babesia 8 weeks after vaccinatin fr Anaplasma lss f appetite Recmmendatins fr use Cattle f any age can be vaccinated, but it is best t vaccinate animals at 3-9 mnths f age when there is little risk f reactins t the vaccine. stablerandhwlett.cm.au
The risk f reactins is greater when vaccinating adult cattle (especially bulls and pregnant cws) and they shuld be clsely bserved during reactin perids. Develpment f tick fever immunity after vaccinatin Fllwing a single vaccinatin, immunity t tick fever takes a number f weeks t develp, but the immunity is usually lifelng. Cattle can be at risk f develping tick fever if expsed t ticks befre the vaccine immunity has taken effect. This is nly f cncern in animals lder than 9 mnths f age. The mst cmmn type f tick fever, Babesia bvis,is transmitted 1-3 days after the attachment f the larval (seed) tick. Pur-n and injectable tick cntrl chemicals d nt kill seed ticks sn enugh t prevent the transmissin f Babesia bvis. Cmmnly used dip chemicals have shrt residual activity. Prtecting cattle while immunity develps Yu can minimise the risk f tick fever in intrduced cattle by vaccinating at least 60 days befre cattle enter tick-infested areas. This allws time fr immunity t develp fr all 3 tick fever rganisms. If a 60-day delay in mving cattle is nt pssible, then: delay mvement fr 3-4 weeks after vaccinatin t allw immunity t bth species f Babesia t develp islate intrduced animals frm ther lcal cattle fr 60 days after vaccinatin t help prevent transmissin f anaplasmsis keep animals tick-free befre and fr 28 days after vaccinatin when vaccinating animals that have been intrduced int a tick-infested area. This is very difficult t achieve, s yu must mnitr the cattle carefully during the perid when immunity is develping. Mving cattle befre immunity has develped If it is nt pssible fr yu t delay the mvement f cattle, mve them befre day 7 r frm 21 t 30 days after vaccinatin. These 'windws' prevent animals being transprted and stressed during reactin perids, but the risk f disease frm field infectin still exists until immunity develps. Reactins t tick fever vaccines After vaccinatin, the rganisms in the vaccine multiply and mimic the prgress f naturally acquired disease. Hwever, the rganisms in the vaccine are much less virulent than rganisms acquired in the field frm ticks. stablerandhwlett.cm.au
Calves vaccinated at 3-9 mnths f age rarely shw visible reactins. Older cattle rarely shw visible reactins after vaccinatin, but, in severe cases, animals may have a persistent fever r anaemia. Bulls r pregnant cattle may be mst at risk. Severe reactins are rare, but can ptentially result in lss f cnditin, abrtin, temprary reductin in bull fertility, and, n rare ccasins, death. Yu can manage reactins by mnitring the animals and treating if required. Nte: The cnsequences f an utbreak caused by a virulent tick-brne infectin far utweigh the risks assciated with vaccine reactins. Vaccine reactins are als easier t manage than a disease utbreak because f the predictable reactin perids. Vaccine reactin perids Babesia: 7-21 days after vaccinatin Anaplasma: 30-60 days after vaccinatin Signs f vaccine reactin Babesia Fever General signs f ill health - lethargy, weakness, reduced appetite Red urine - als knwn as 'red water' Anaemia - pale mucus membranes in muth, eyes and vagina, as a result f lss f red bld cells Anaplasma Anaemia Weight lss Mnitring reactins t tick fever vaccines Individual animals Reactins can be detected sner by mnitring cattle fr the develpment f fever rather than the clinical signs assciated with Babesia spp. in the vaccine. Yu can d this by measuring early mrning rectal temperatures in the perid 10 t 21 days after vaccinatin. This is particularly imprtant in bulls r heavily pregnant cws. Treat prmptly if fever exceeds 40.5 C r if yu see ther signs f severe reactins. Fever is nt a useful indicatr fr Anaplasma reactins. Daily visual mnitring fr clinical signs frm 30 days after vaccinatin will be adequate. stablerandhwlett.cm.au
Paddck mnitring With larger herds f cattle, bserve the animals daily during reactin perids. Be sure t mve them arund t better detect stragglers and check fr clinical signs. If any signs are detected, mve them t yards t take rectal temperatures, cllect apprpriate samples and treat as necessary. Sampling animals t cnfirm vaccine reactins Samples taken frm animals with suspected vaccine reactins can help cnfirm r rule ut whether a vaccine reactin was the cause f the illness. Discuss sample requirements with yur lcal veterinarian, Bisecurity Veterinary Officer r Tick Fever Centre staff. Stabler and Hwlett wuld like t thank ur partners at Zetis fr their assistance in cmpiling this dcument. We recmmend and sell the Zetis range f cattle vaccines. stablerandhwlett.cm.au