MEETING THE PARASITE PROTECTION NEEDS OF PETS AND CLIENTS Part 2

Veterinary webinar by IAN WRIGHT BVM&S MSc MRCVS, Reviewed by David Grant

Acaricides 

  • Spot on preparations, collars and tablets are all available
  • Rapid kill repellency or expellency
  • No product is 100% effective
  • Checking for ticks daily and removing them is also important
  • There are 8 products currently licensed. Information on these can be found on the ESCCAP UK and Ireland website esccapuk.org,uk

When to recommend chemoprophylaxis

  • This is a risk based assessment based on a consideration of vector borne disease, and a combination of prevalence and frequency of exposure
  • Dog walks in an area with known tick/Lyme disease prevalence or in areas adjacent to sheep and cattle
  • Previous exposure to ticks
  • Client concern re Lyme disease

The responsibility for advising the public

  • Local government advises the public via notices predominantly displayed in endemic rural areas
  • The veterinary profession. Ensure that clients can recognise ticks both on their pets and on themselves

Removing Ticks

  • Make sure the client can recognise that it is a tick before they attempt removal
  • Tweezers-these should be fine point –not blunt, as risk of ‘stressing’ the tick, which results in regurgitation of stomach contents and enhanced possibility of disease transmission
  • Tick Hooks. These come with illustrations on how to use involving the twist and pull principle, These are recommended
  • Tickner removal system. Freezes the tick prior to removal.

INTERNAL PARASITES

TOXOCARA CANIS AND TOXOCARA CATI

  • Intestinal nematodes of dogs and cats
  • The most common nematode seen in small animal practice
  • There is some public awareness of the zoonotic potential of these parasites
  • Vets are often asked about them

Life Cycle

  • Unembryonated eggs in faeces
  • 2-7 weeks to reach infective L3 larval stage. Fresh faeces not zoonotic
  • Transplacental and transmammary most important route of infection in dogs
  • Transmammary and via paratenic host (hunting) most important in cats
  • Nearing 100% infestation in puppies and kittens
  • Natural immunity develops by 6 months Adult prevalence is then between 10 and 20%(feral) but because of intermittent shedding of eggs the risk is difficult to predict

Pathogenesis in dogs and cats

  • Well tolerated but high burdens can cause loss of body condition and possible intestinal obstruction or intussusception
  • Larval migration through lungs can lead to chronic pulmonary and interstitial damage, particularly in cats
  • Signs can occur without egg production-either prepatent or due to intermittent shedding

Zoonotic potential

  • 2-4 year olds are the highest risk group but can also affect adults
  • Visceral (migration through the lungs and liver) and ocular larval migrans
  • Also neurological and covert forms occur. Sero-conversion represents risk factor for epilepsy. Covert forms may be associated with dermatitis and asthma
  • People can be infected by ingesting embryonated eggs of canis and T. cati.
  • Eating undercooked game, pheasant for example, is an important source of infection
  • Geophagia (either pica or natural behaviour of young children) is an important cause of infection in areas where dogs and cats defaecate, sand pits for example
  • Sero prevalence is between 2-31% of people in Europe (approximately 2% in the UK)
  • Incidence of human disease is 2 cases per million per year. This figure may be smaller than actual disease due to underreporting. The disease is not notifiable, although a system of voluntary reporting to the Health Protection Agency (HPA) is in place
  • Even though the number of cases is very small each case is a tragedy for the afflicted person/child given that the disease is entirely preventable
  • The risk of infection increases in households with puppies, kittens and children and where there is more than one pet.

Control of Toxocara

  • Regular de-worming of all dogs and cats
  • Picking up dog faeces
  • Covering up sand pits (a perfect embryonation area for Toxocara)
  • Good hygiene around pets

De-worming frequency

  • De-worming every 3 months has been shown to significantly reduce ova shedding and should be considered a minimum recommendation
  • There is no evidence of any benefit from de-worming at 4 to 6 month intervals
  • Monthly de-worming will block canis and T. cati ova production by more than 90%. This is recommended for pets in households where there are children, individuals with compromised immune systems, with pets that regularly hunt, and in multi -pet households
  • With puppies and kittens de-worm every 2 weeks until 2 weeks post weaning and then monthly to 6 months
  • All currently available de-worming products are effective against Toxocara

Tapeworms

U.K tapeworms discussed in this webinar included Taenia sp. Dipylidium caninum and Echinoccus granulosus

Taenia

There are a number of species and these are common across the UK. With prey species the sheep is an intermediate host, and there are a variety of other intermediate hosts.

  • Eggs are rarely seen in faecal flotation
  • Active segments may be seen in faeces
  • Prevalence depends on risk factors such as eating raw meat or hunting
  • Generally well tolerated except in high numbers, where there may be a loss of condition, and in heavy numbers causing intestinal obstruction

Dipylidium caninum

  • Flea is the intermediate host
  • Very mobile segments
  • High prevalence everywhere
  • Zoonotic potential from ingesting flea parts under the finger nails, for example
  • Can easily be controlled by anthelminthics every 4-6 weeks but effective control is also by comprehensive flea control

Frequency of tapeworm treatment

Not much evidence has been compiled to help with this question, although this is changing due to the significance of Echinococcus granulosus.

Echinococcus granulosus is non-pathogenic in canids and there are a number of sub species

  • Echinococcus granulosus sensu stricto is zoonotic with sheep the intermediate host
  • artleppi is also zoonotic but humans are not as readily infected. Cattle are the intermediate hosts
  • Both are a significant cause of hydatid disease

Hydatid Disease (Echinococcosis)

  • Prevalent in mid Wales, Herefordshire, and western Isles of Scotland
  • Welsh hot spots are Powys, Monmouthshire, south Herefordshire adjacent to Powys
  • 10-20 cases per year in the UK
  • Cysts may lodge in the liver, heart, CNS or bone

Diagnosis of tapeworm infestation

  • Faecal examination unreliable
  • granulosus may also be missed at post-mortem
  • Adults are only a few mm long
  • Segments may be seen In the faeces or crawling from the anus

Tapeworm Control

  • In endemic areas it is essential to treat for tapeworm every 4-6 weeks
  • Praziquantel is used and more conveniently as part of an overall parasite control programme
  • artleppi has been found at meat inspection in the midlands and Cheshire and the incidence is increasing across the UK
  • Using hunting and feeding of raw meat/offal as a guide a risk based assessment can be made for the frequency of tapeworm treatment
  • Recommended 4 times per year in non-endemic areas. Every 4- 6 weeks in high risk areas or with hunting dogs or those that have access to raw meat

Common lungworms of the dog and cat in the UK

Angiostrongylus vasorum –dog

Crenosoma vulpis –dogs and foxes

Oslerus (Filaroides) osleri –dogs

Aelurostronglylus abstrusus –cats

Angiostrongylus vasorum

  • Capable of causing severe disease syndromes in dogs
  • Contracted by the ingestion of slugs, snails and frogs
  • The parasite has spread from local foci in Wales, the south coast and south west England and is now prevalent almost anywhere in the UK
  • There is a high prevalence in foxes (the reservoir host) and this has increased significantly in all endemic areas in the last 8 years or so
  • Local ‘hot spots’ occur and there can be rapid changes in prevalence
  • Likely factors for the increase include climate change (milder winters), increased number of foxes, increased number of snails and increased movement in dogs.

Clinical signs

  • Cardio-pulmonary-cough is the most common sign due to parasitic bronchitis
  • Neurological signs
  • Coagulopathies
  • Other lesions caused by aberrant larval migration –to the eyes for example

Treatment

  • Anthelminthics-initiate treatment with these as early as possible
  • Suitable anthelminthics include Imidacloprid oxime + Moxidectin (0.1 ml/kg) Licensed as a spot on. Milbemycin oxime (0.5 mg/kg) once weekly for 4 weeks Licensed. Fenbendazole (25-30 mg/kg) daily for 7-21 days. Not licensed but popular use on grounds that ‘slow kill’ is beneficial. Not backed up by peer-reviewed evidence. Ivermectin and Levamisole have been used but with these drugs there is a toxicity risk
  • Supportive treatment. Steroids for anti-inflammatory use and for instances of anaphylaxis. Oxygen for cases with respiratory difficulty
  • Prognosis with early diagnosis and treatment is good
  • Monthly prophylaxis is essential in known endemic areas
  • In non-endemic areas use testing and or screening to enable specific recommendations to be made.

 

 

 

 

 

 

 

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