Page 41 - VetCPD Jnl Volume 7, Issue 4

Peer Reviewed
VETcpd - Parasitology
Is monthly treatment of cats and
dogs for worms and routine flea
treatment essential?
Whether and when monthly preventative deworming regimes in cats and dogs should be used, and under what circumstances continues to be debated both
inside and outside the UK veterinary profession. Toxocara spp. and Echinococcus granulosus are zoonotic and Angiostrongylus vasorum is potentially highly pathogenic to dogs even if present in low numbers. It is the risk of exposure to these parasites which forms the basis of UK deworming guidelines. The need for routine flea treatment is also fundamental to parasite control protocols in cats and dogs. The benefits of routine flea treatment need to be considered against the possible environmental impact and drug resistance issues that may be associated with long term use. This article considers a risk based approach for establishing whether monthly deworming of UK cats and dogs is required and whether routine flea treatment of all cats and dogs is justified.
Key words: fleas, toxocarosis, Echinococcus granulosus, Angiostrongylus vasorum zoonosis, prevention
Ian Wright
BVMS BSc MSc MRCVS
Ian is a practising Veterinary Surgeon at the Withy Grove Veterinary Surgery and co-owner of the Mount Veterinary Practice in Fleetwood. He has a Master’s degree in Veterinary Parasitology and is Head of the European Scientific Counsel of Companion Animal Parasites (ESCCAP UK & Ireland). Ian is regularly published in peer reviewed journals and is a peer reviewer for the Veterinary Parasitology and Companion Animal journals. Ian continues to carry out parasite prevalence research in practice. The Mount Veterinary Practice
1 Harris Street, Fleetwood, FY7 6QX
Tel: 01253 875547 or 07816337293 E-mail: hammondia@hotmail.com
Introduction
The ubiquitous nature of flea and Toxocara roundworm infection makes treatment frequency for fleas and worms in cats
and dogs fundamental routine advice
that veterinary professionals give to pet owners across the UK.When considering parasite treatment frequency for UK cats and dogs, the zoonotic and health impact of endemic parasites must be assessed and evidence based recommendations made.
Disease in cats and dogs caused by helminths in most cases is correlated
with worm burden. Monthly tapeworm treatment may be adopted in cats and dogs with visible tapeworm proglottids due to the owner revulsion these segments cause, but less frequent treatments for tapeworm infections are normally adequate to control clinical disease in cats and dogs. Similarly, treating intestinal roundworms four times a year is likely to keep worm burdens low and reduces zoonotic Toxocara spp. ova output (Wright & Wolfe 2007). Monthly treatment, however, is required to prevent Toxocara spp. shedding in cats and dogs likely to have high worm burdens,
or that live with people at high risk of infection. Echinococcus granulosus is a highly zoonotic tapeworm with endemic UK foci.Treatment of dogs at risk of infection every six weeks with praziquantel will prevent egg shedding and minimise zoonotic risk although monthly treatment is often more convenient for owners to remember and synchronise with other
flea and worm treatments. Angiostrongylus
vasorum is highly pathogenic nematode of dogs and is spreading across the UK.This parasite may cause disease in pet dogs, even if low worm burdens are present. Monthly preventative treatment must therefore be considered for dogs at risk of exposure.
Cat flea infestations are also common throughout the UK with a recent study showing 28% of cats and 14% of dogs infested (Abdullah et al. 2019).Although cat fleas cannot live and reproduce on people, they can bite leading to human irritation.They are also a source of revulsion, eroding the human-animal bond.They are a cause of flea allergic dermatitis, anaemia in heavy infestations and vectors for a variety of zoonotic infections including Bartonella spp. and Rickettsia felis. Routine flea treatment is, therefore, also vital to prevent infestations establishing and exposure to flea-borne pathogens occurring.
Angiostrongylus vasorum
The life cycle of A. vasorum (Figure 1) requires and intermediate host. First stage larvae (L1) pass out in the faeces and require gastropod molluscs (slugs and snails) for further development. Infection occurs in canids when infective third stage larvae (L3) are ingested.This occurs most commonly through deliberate
or accidental consumption of infected slugs or snails (Morgan et al. 2005) but can also occur through the ingestion of paratenic hosts such as frogs.
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