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IT IS interesting to see how news of a disease outbreak develops and spreads. In February, Veterinary Record published a short letter from Clive Swainsbury and colleagues at the Forest Veterinary Centre, drawing attention to an outbreak of babesiosis in dogs in Harlow in Essex. Over the previous three months, the disease had been identified in three dogs from three different households. The dogs had been exercised in a local uncultivated park area, and Dermacentor species ticks had been recovered from two of them. Significantly, none of the dogs had travelled abroad (VR, February 13, 2016, vol 178, p 172).
A few weeks later, in a follow-up letter, Mr Swainsbury along with Paul Phipps and others at the APHA and Public Health England confirmed that Babesia had been detected in a Dermacentor reticulatus tick recovered from one of the dogs, identifying the species as Babesia canis. They also gave details of a more recent case presented at the Forest Veterinary Centre, in which B canis was identified both in a blood sample from the dog and from an engorged tick recovered from the dog (VR, March 5, 2016, vol 178, pp 243-244). This is not the first time babesiosis has been found in a dog in the UK that has not travelled abroad, as a case was described in a dog in Kent 10 years ago (Holm and others 2006), but it is the first clear evidence that the disease may be circulating. In their letter, Phipps and others warned dog owners to be on the lookout for ticks, and to consult their vet if their dog developed signs of disease including lethargy, fever and anaemia.
About a week later, on March 13, the outbreak was reported by BBC News Essex. It was subsequently picked up by other news outlets and, by the middle of last week, was being widely reported in the national press. Meanwhile, in a further follow-up letter in this week's Veterinary Record, Kayleigh Hansford and others discuss the results of a tick survey that has been carried out in the area of Harlow where the affected dogs were exercised, which has provided evidence that a Babesia-infected tick population is present in the area. They describe steps being taken to warn dog owners of the risks to their dogs locally. They also advise vets in the area to be aware of the possibility of dogs without a history of travel abroad presenting with babesiosis, and, while noting the D reticulatus vector is not widely distributed in the UK, raise the possibility that it might also arise in other areas (see p 323 of this issue).
Reports that B canis might be circulating in this area of Essex are worrying, and certainly newsworthy. However, they shouldn't come as a surprise, as vets and others have been warning about the possibility of babesiosis and other tickborne diseases being introduced into the UK from Europe ever since the Pet Travel Scheme was introduced in 2000, and even before (Trees and Shaw 1999, Trees 2009, Abbott and others 2011). Indeed, it was because of concerns about a tickborne disease that affects people – Mediterranean spotted fever, carried by the brown dog tick, Rhipicephalus sanguineus – being introduced that, until 2012, when Europe's pet travel rules were harmonised, all pets entering the UK had to be treated against ticks 24 to 48 hours before entering the country. That requirement was dropped when the pet travel rules were harmonised in 2012, although treatment against ticks is still strongly recommended (Fooks and others 2011).
As Richard Wall argued in an Editorial in Veterinary Record three years ago, the changes to the pet travel rules, together with an expansion in the range of a number of tick species, mean that the veterinary profession and the public need to become more aware of the risks of tick infestation and tickborne diseases: effective control and management requires an understanding of the biology and ecology of ticks, the pathogens they might transmit and how transmission occurs, and education, awareness and surveillance are of paramount importance (Wall 2012). His Editorial provided a useful summary of the nature of the risks, as well as discussing the particular circumstances that would be necessary for certain pathogens to be introduced and become established.
The precise pathway through which B canis seems to have entered the English tick population remains unclear. However, it does look as if, in this instance, the necessary circumstances have come together. The hope, at this stage, must be that the problem is confined locally, and to this combination of tick and disease. However, as the number of pets entering the country continues to increase, and ticks show signs of extending their range, it is hard not to be concerned about the future, and more attention needs to devoted to surveillance and tickborne diseases generally.