In Ireland, we have certain parts of the country and certain land types which have ticks on them. This can pose a risk to cattle and sheep because these ticks can often transmit diseases. One disease that many farmers will be familiar with is redwater. This disease is also called babesiosis and is associated with a small parasite called babesia divergans. The ticks transfer this parasite into the blood of cattle when they feed on them. So, with several cases being reported for the last two weeks, now we need to be on high alert but also know how to prevent it where possible.

The parasite attacks and destroys red blood cells in cattle, hence the name redwater, and this is where the damaged red blood cells are passed in urine giving it a darkened appearance.

The tick population

With the tick being key to transmitting the disease, we must look at where tick populations are. The tick goes through three stages of development over four-to-six years, starting as an egg, to larvae, to nymph, and finally to an adult. Each time it needs a blood feed to develop to the next stage. It will actually latch onto a host like cattle for three to 10 days and feed, when a tick is infected it will spread this parasite through the feeding activity at all stages.

Cattle usually won’t show symptoms for three-to-four weeks after this exposure to the tick. The parasite babesia enters the blood and will attack red blood cells that carry oxygen, this is why we see the symptoms we describe later.

The ticks themselves like wet, damp conditions and are active in late spring and early autumn. However, this has changed with reported cases later and earlier each year. The tick also likes a certain habitat, which can be rougher grazing ground, but this doesn’t mean we can’t find ticks in ordinary grasslands. Generally, they like the shade and don’t like direct heat or sunlight for long periods.

The last two weeks have also been perfect weather for ticks to appear and start looking for hosts like cattle. In certain parts of Ireland, increasing deer populations have seemed to enable the spread of ticks also. So, many farmers will know if their ground has ticks on it. If not, you might at least know there is a risk. Not every tick will carry redwater, but unfortunately they can carry other disease as well.

A word of warning: ticks can also transfer lymes disease, which can affect humans. Any farmer who gets bitten by a tick should consult with their doctor.

Immunity

There is a very important factor with redwater and that is young animals in tick areas will have very good immunity against the disease up to 9 months of age. In fact, young animals before 6 months will generally not get redwater, as it affects older stock mainly. This is why animals in certain areas rarely succumb to the disease, but bought in stock with no exposure pose a massive risk. Older stock can get the disease but usually it is animals that have been brought into a tick area with redwater, who have no previous exposure.

Urine can have dark frothy consistency with redwater.

What are the clinical signs?

There are really two stages to the disease, early on the disease requires careful observation to pick it up. The value of at least one daily walk through stock to pick up symptoms is so important.

Symptoms early on

  • Can be lying down, unwilling to stand until approached.
  • Separated from the herd.
  • Look empty on the flanks.
  • High temperatures with heavy breathing.
  • A scour or what we refer to as pipe-steam diarrhoea.
  • Not eating.
  • Can have frothy urine that is red in colour or dark brownish.*

    • *Other diseases that can be present with red or dark urine can be: low phosphorous, nitrate poisoning, copper toxicity or fern poisoning.

    Symptoms later on:

  • Very weak or staggering.
  • Unable to rise even when approached.
  • Constipated.
  • Animals can feel colder.
  • The urine colour can be normal.
  • White around eyes and mouths.

    • We will discuss treatments but like any disease, early identification makes all the difference.

  • Tip: spend time walking through stock and getting them up and stretching.

    • Treatment

    Once an animal has been diagnosed, usually by the symptoms we described, your vet can give medicine to treat these cases. This product is known as imidocarb or Imazol. This works on its own when animals are spotted early, but requires careful monitoring and often I give oral iron supplementation for several days after.

    Most cases, when they are spotted later, require blood transfusion as the red blood cells are too low. This is why these animals are weak, the parasite has attacked and destroyed the red blood cells which carry oxygen around the body.

    Be very careful with anaemic cattle, they can be very unpredictable and sometimes dangerous. Heavy stress can also cause death. We usually will take blood for the transfusion from an older animal like a mature cow. We can give 5l-10l of blood by infusion slowly along with imidocarb, which works well. These animals of course need careful handling and monitoring for the following 48-72 hours.

    Prevention

    Reducing exposure to ticks would seem like an obvious way of preventing the disease. Of course this is very difficult but anywhere that rough ground is reclaimed makes it less tick friendly. With most cattle in tick areas having some resistance, we can assume they are low risk but vigilance is still required. Spot-on preparations will often give three-to-four weeks of cover where animals are being released into high-risk areas. This may allow some immunity to develop, but often requires repeat applications. Remember, cattle ticks can carry other diseases so the spot-ons are important where high levels of ticks are seen. The imidocarb dipropirante can also be used to prevent redwater. Give twice the dose of treatment under the skin before the risk period.

    This protection only lasts four weeks and also has very long withdrawals of 21 days for milk and 218 days for meat.

    This is not a vaccination and will only last for four week. Any bought-in cattle to tick areas should be treated before turnout, when ticks are active and should have a spot-on treatment like flumetrin or amitraz.