Parasite control critical in keeping diseases out of UK - Veterinary Practice
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InFocus

Parasite control critical in keeping diseases out of UK

VETERINARY PRACTICE
reports on a recent meeting called to
discuss the changes being made to the Pet
Travel Scheme and their likely effects

VETERINARY practices are being asked by ESCCAP UK to provide feedback on their experiences following the changes to the parasite control rules and regulations that are expected to come into force on 1st January 2012. The organisation can be contacted via info@esccapuk.org.uk or via the website www.esccapuk.org.uk. A meeting at Bristol of some 40 veterinary surgeons and nurses learned that there will no longer be mandatory tick treatment and mandatory tapeworm treatment is to be confirmed. Pet owners will have greater responsibility and will need to understand that parasite control is critical in preventing exotic parasites and vector-borne diseases entering the UK. Liz Abbott and Maggie Fisher of ESCCAP UK (European Scientific Counsel Companion Animal Parasites) introduced the topic and explained the activities of the organisation, which is funded by commercial companies and has branches in European countries. A film of the presentations is available on the web at www.keyskill.com.

Background

Dr Balazs Toth from the AHVLA (balazs.toth@ahvla.gsi.gov.uk) outlined the background that since 2000 750,000 pets have been involved in the pet travel scheme with about 100,000 pets going abroad each year. The existing rules for citizens of the EU require the pet to be microchipped, vaccinated, blood sampled, six months wait and then issued with a passport certificate. This will be changed to the pet being microchipped, vaccinated, 21-day wait and then issued with a passport and free to travel. Full details of listed countries where the rules apply and the rules for other countries are on the DEFRA website. The new rules are primarily designed to protect humans, says DEFRA. There is concern that harmonisation of the pet travel scheme across Europe will increase the disease risks for the UK. It is recommended that pets, before leaving the UK, are treated for ticks and tapeworms with treatment options on their return. The number of animals going into quarantine will drop. DEFRA recognises that there is a real risk that there will be confusion about the need for treatment in various locations.

Thinking about rabies

John Helps of MSD Animal Health explained that here in the UK we will need to think more about rabies in the future. Throughout the EU wildlife is the main risk vector whereas domestic and stray dogs are recognised risks in other areas. Dog bites account for 99% of human cases of rabies. The latent period from bite to disease is 3-8 weeks in dogs and up to 12 months in humans. From the bite wound the Lyssavirus travels at 10cm per day before entering the brain and is replicated in the spinal cord. The closer the bite wound to the brain, the shorter the incubation period with more rapid onset in children because they are often bitten around the head. In the EU 700 bats have been identified with EBLV-1 and six rare Daubenton’s bats with EBLV-2 have been identified in the UK. Four human cases of rabies infection have been confirmed in Europe. A programme of vaccination in the Serengetti has realised a dramatic drop in human cases, a dramatic drop in dog cases and the return of African wild dogs that were previously wiped out. Further
information about this work is being collated and will be published in Veterinary Practice. It is feared that the new pet travel rules will encourage more dogs to be brought into the UK with an increased risk of rabies. A one-dose vaccination provides
adequate protection in most dogs. In consideration of bats, Erin Morgan (University of Bristol) explained that one of the students had calculated that it would take the blood content of 21 people to satisfy the nutritional requirements of a human vampire. Moving on to tapeworms (Echinococcus multilocularis), fox faeces contain millions of eggs. The urbanisation of foxes offers a greater risk to the suburb dwellers than to country dwellers.
Traditionally the surveillance of foxes has been carried out by gamekeepers but this work now needs to be carried out in towns and cities. The fox is the definitive host with voles being predated by foxes as the intermediate host. It is important to control tapeworms in dogs. There is a 98% chance that dogs who visit endemic Europe for two weeks without treatment will
introduce Echinococcus.

Parasite on the move

The parasite is travelling westwards from Eastern Europe.
Praziquantel kills adult worms and daily doses of albendazole will suppress the slow growing cysts. Screening faecal samples is a risk to operators. Ticks and tick-borne diseases were highlighted by Faith Smith of the veterinary parasitology and ecology group at the University of Bristol. Ticks are found on dogs in each month of the year but ticks have optimal activity at 17-20°C and survive for three to eight years. Two to three thousand eggs are laid that develop into six-legged larvae that become eight-legged nymphs and then eight legged adults. With warmer, wetter winters more ticks are found further north in Europe. Of 3,534 dogs examined in the UK, 810 (14.9%) had ticks, although many were small and relatively unengorged and would go unnoticed by owners. It is believed that only a quarter of the cases of Lyme disease (Borrelia burgdorferi) in humans (953 in 2010) are reported each year and more sensitive means of diagnosis are sought. Ixodes ricinus (castor bean tick) is a common tick in the UK and other countries and I. canisuga (British dog tick) and I. hexgonus (Western Europe) is observed in dogs and cats. Overseas the brown dog tick Rhipicephalus sanguineus transmits babesiosis. Dermacentor reticulatus has been recorded on dogs in Wales for some years but is now known to inhabit south-east England. The ticks typically attach to long grass and bracken and hook into the coat of warm-blooded animals where they feed on blood. Diseases are transferred from earlier feeding sessions from animal to animal and animal to man. Deer are often found with tick infestation and the increase in deer numbers may account for a rise in risk from ticks in many areas. An increase in animal movements out of and into the UK will increase the risk of dogs and cats being presented at surgeries with vectorborne diseases, according to Jackie Barber of Liverpool University, who highlighted the difficulties of treatment for leishmaniasis (protozoa) and dirofilariosis (heartworm). Advice to prevent these diseases is essential. Leishmania infantum is transmitted in Mediterranean countries by phlebotomine sandflies. Humans are infected by the sandflies, not from dogs. This is a disease of “tatty” dogs with a long incubation period of months eventually leading to death.

CHANGES TO PETS

Oral treatment over months is available, is expensive and may provide clinical improvement but does not eliminate the parasite.

Keep dogs indoors

Most cases in dogs in the UK are where the dog has lived abroad, for example where the owner has a holiday home. Sandflies are silent (unlike mosquitoes) and are active from dusk ’til dawn. The advice is not to have the dog with you outside in the evening or to
sleep outside. There is no vaccine so repellents and insecticides including collars are essential. Collars need to be applied at least
one week before going to an at-risk area and need to be removed before swimming to protect aquatic life. Renewal is normally required every 5-6 months. Heartworm (Dirofilaria immitis) is spread from mosquito bites with an incubation period of several months before clinical signs. Treatment is difficult and expensive
with complete rest and hospitalisation including therapy for ongoing heart failure. Surgery may be required to remove the worms. Prevention of insect bites is essential with insecticides plus
preventive medication. If a dog has previously been to an at-risk area, it is advised to test for microfilaria. The Virbac Canileish vaccine is available abroad but the third dose needs to be given in the UK and a preventive dose for animals going back abroad. Anna Judson of Camlar Vets in Welshpool and Maggie Fisher proposed the need for a “pet travel champion” within veterinary practices
to run pet travel clinics and to generate newsletters and reminders to pet owners. Owners are likely to need advice on the pet travel rules for their particular travel areas. A range of leaflets and other
resources are freely available from Laura Yeadon at ESCCAP. Within the website, guidelines for treatment and control are available and a search by country and parasite with parasite distribution maps will be useful. The site has a pet owner and a professional section. Anyone with ideas for better advising pet owners is invited to contact ESCCAP.

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