Cats and dogs carry a wide range of parasites endemic in the UK with pathological and zoonotic potential. Many of these are intestinal dwelling and pass infective life stages in the faeces which may then directly infect other hosts. This mode of transmission is known as the faecal-oral route and preventing exposure is key to breaking the life cycle of these parasites and improving the health of both pets, owners and the wider public as a result. Veterinary nurses (VNs) have a vital role to play in educating pet owners in the part they must play in achieving this. Parasites transmitted by the faecal-oral route are numerous, but the ones presenting the greatest risk in the UK fall into three groups: Toxocara roundworms, intestinal protozoa and tapeworms.
Toxocara spp.
Toxocara spp. are a group of intestinal nematodes with species infecting dogs (Toxocara canis) and cats (Toxocara cati), both of which have zoonotic potential. Adult worms lie in the small intestine and shed eggs into the environment via the faeces of the host. The eggs when first shed are un-embryonated and not infective. Progression to the infective embryonated L3 stage is required for infection, so fresh faeces do not present a zoonotic risk with embryonation taking place in 2 to 7 weeks under optimum conditions. Although dogs may be infected by ingesting embryonated eggs, the most important route of canine infection is trans-placental. Dogs and cats may also become infected by trans-mammary infection or consuming paratenic hosts such as rodents. The most common route of human infection however, is by the ingestion of embryonated eggs. Oral ingestion of embryonated eggs can lead to a variety of disease syndromes in people including visceral and ocular larval migrans. Seropositivity in humans to Toxocara spp. has been demonstrated to be a risk factor for chronic disease such as epilepsy and cognitive dysfunction. When first passed, Toxocara spp. ova are not infective to humans for several weeks and immediate infection by the faecal-oral route cannot occur. The uncontrolled passing of ova by cats and dogs, especially puppies and kittens, however, will lead to significant build-up of ova in the environment with the potential for zoonotic infection in the longer term. Methods used to control faecal-oral transmission are therefore relevant to human toxocarosis prevention. These measures include:
- Regular deworming of cats and dogs: puppies and kittens provide the largest source of potential infection. Treatment of puppies should start at 2 weeks of age and should be repeated at 2 weekly intervals until 2 weeks post weaning and then monthly until 6 months old. Kittens should be treated in the same way, but the first treatment can be given at 3 weeks old as there is no trans-placental transmission. It has been demonstrated that use of an effective anthelmintic every 3 months significantly reduces Toxocara spp. ova shedding (Wright and Wolfe, 2007). Therefore, this frequency should be a minimum recommendation in dogs and cats. Pets that hunt, are fed an unprocessed raw diet, are in contact with young children and/or immunosuppressed individuals should be dewormed monthly. Toxocara spp. is susceptible to a wide range of anthelmintics licensed for use in cats and dogs. Educating clients on the zoonotic risk and importance of routine treatment can help to increase compliance.
- Minimising environmental contamination with cat and dog faeces: UK county councils are taking the threat of dog fouling increasingly seriously but cat faecal contamination with Toxocara ova also needs to be considered to reduce human exposure overall. Covering sand pits when not in use to prevent faecal contamination from cats will help to avoid children playing in these areas being exposed to ova. Washing of outdoor toys prior to use is also recommended.
- Hand hygiene: washing hands, particularly before preparing and handling food will help block transmission of a number of different faecal-oral parasites including Toxocara spp.
- Washing of fruit and vegetables intended for raw consumption: produce from gardens and allotments can easily be contaminated with cat faeces and as a result should be washed before consumption.
Intestinal protozoa
There are several clinically relevant protozoa infecting cats and dogs transmitted by the faecal-oral route. There are no proven preventative treatment regimens for these parasites and control is therefore dependent on rapid diagnosis and environmental management. Examples are Giardia spp., Tritrichomonas foetus and Isopora spp.
Giardia duodenalis (intestinalis, lamblia)
Giardia duodenalis is a flagellate protozoan of the intestinal tract of many mammals including humans, cats and dogs. Many infections are subclinical with the most common clinical sign being chronic, sometimes intermittent small bowel diarrhoea. Less commonly there may be large bowel involvement with tenesmus and the presence of mucous and fresh blood in the faeces. The life cycle of Giardia is direct. Trophozoites divide by binary fission in the small intestine and form infective cysts which are passed in the faeces. Transmission then occurs through contamination of the coat, environment, food and water. While some species of Giardia are species specific, Giardia duodenalis can infect many mammals including humans, livestock and pets. Prevalence of subclinical infection is high in cats and dogs, particularly in pets under 1 year old (Ballweber et al, 2010). Although there is some debate around sub classification of this species, it is currently split into eight sub-groups or assemblages. Humans are infected with assemblages A and B, with infection from the other assemblages being very rare. Dogs are predominantly affected by assemblages C and D and cats by assemblage F. Cats and dogs may be infected by assemblages A and B, however, if they are exposed to environmental contamination from human infection (Caccio et al, 2005). Therefore, it is vitally important that people infected with Giardia either avoid contact with puppies and kittens or observe strict barrier hygiene to minimise zoonotic risk.
If diarrhoea is being investigated then diagnosis can be achieved by examination of faeces by direct smear or faecal flotation. Direct smears have a low sensitivity for Giardia cyst detection, but if faeces are examined immediately then trophozoites may be seen. These are active, and move in a characteristic ‘falling leaf motion’. Sensitivity for cyst detection is increased both by faecal flotation methods and pooling faeces over 3 days. Both trophozoites and cysts are approximately 15 µm with the cyst sometimes having a visible flagellum crossing the ova in an ‘s’ shape. A drop of Lugol's iodine added to the faecal prep will stain the cysts, making them easier to identify. Highly sensitive enzymelinked immunosorbent assay (ELISA) snap tests are also commercially available for diagnosis of infection. These are convenient to use but will detect recent, as well as current, active infection.
Tritrichomonas foetus
T. foetus is a similar flagellate protozoan to Giardia, infecting the large intestine of cats. Many infected cats are subclinical carriers with clinical cases being more common in cats under 12 months old. Clinical outbreaks in litters of kittens can occur with untreated clinical cases either self-curing or remaining as carriers, intermittently shedding the organism. Colitis is the most common clinical sign with malodorous chronic diarrhoea. Blood may be present in the stool with large volumes of mucous. Chronic weight loss can occur, suggesting a degree of small bowel involvement.
The life cycle of Tritrichomonas is direct with trophozoites ingested from fresh faecal contamination, either from the environment or from grooming faeces from the coat. Cross contamination of fresh faeces is thought to occur most commonly in shared litter trays, and breeding colonies are over represented for clinical disease, as are young and pedigree cats. Dense stocking conditions of cats in breeding situations will lead to increased likelihood of faecal-oral transmission through faecal contamination in the immediate environment (Slapeta et al, 2010).
Infection can be diagnosed by direct faecal smear examination, faecal culture or polymerase chain reaction (PCR). Direct faecal smears carry a poor sensitivity if faeces are not fresh, contaminated with litter, cool or if antibiotic therapy has been used up to 7 days prior to testing. If active trophozoites are observed they will have a ‘forward jerking’ motion rather than the ‘falling leaf’ motion of Giardia. The ‘in pouch’ faecal culture method (InPouchTF-Feline, BioMed Diagnostics) allows for the culture of faeces in media suitable for Tritrichomonas spp. growth. The test has a higher sensitivity than a direct smear if the pouch can be inoculated and cultured in the practice or faeces can be delivered to a local diagnostic laboratory within a few hours of collection. PCR is the most sensitive test available and has the advantage of being able to detect infection in cool or stored faeces. It is therefore the test of choice if elimination of the parasite is required from a litter or breeding colony. As T. foetus excretion can be intermittent, samples should be tested for 3 consecutive days. Bacterial DNAases will degrade DNA in the faeces so faeces should not be stored for more than 48 hours, unless frozen, prior to the test being performed.
Isospora spp.
Isospora canis and Isopora felis are species specific coccidian protozoa of the small intestine in dogs and cats respectively. Transmission is by the faecal-oral route, with oocysts being passed unsporulated (Figure 1) in the faeces. In warm, humid conditions, sporulation occurs in as little as 2 days, leading to infective oocysts in the environment (Figure 2). Infection is often subclinical even when large concentrations of oocysts are present in the faeces, but projectile small bowel diarrhoea can develop in heavy infections. The risk of severe infection increases as the numbers of infective oocysts increase in the environment. This most commonly occurs when large numbers of cats or dogs occupy a small space, particularly in warm damp conditions. The large number of oocysts shed in clinical infections means that diagnosis can easily be achieved through examination of faeces by direct smear or faecal flotation
Prevention
Although routine preventative chemoprophylaxis has not yet been demonstrated to be of use in controlling intestinal protozoa, environmental control measures need to be employed in breeding establishments, kennels and in individual households containing clinically infected cats and dogs to ensure that environmental contamination with infective parasitic life stages does not build up over time. These include:
- Frequent collection of faeces: increasing the number of litter trays and frequent collection of faeces will help to reduce environmental contamination
- Washing infected and in-contact pets: with shampoo, particularly around the perineum to remove faecal contamination and infective parasitic life stages from the coat
- Disinfection of kennel areas and runs with a quaternary ammonium compound: to reduce environmental contamination with cysts
- Separating un-weaned kitten litter trays from the queen's litter tray: platforms or covers can be employed to prevent the queen access to the kittens' faeces and vice versa. This is important for Tritrichomonas control as nursing queens cannot be treated to prevent shedding.
Canine tapeworms
Tapeworms of dogs have a complex life cycle, requiring an intermediate host. Zoonotic risk from Echinococcus granulosus and meat/offal condemnation from infection of livestock all arise from exposure to infective eggs in the environment due to faecal contamination. The adult tapeworm is found in the intestine, attached to the intestinal wall. Eggs or proglottid segments containing eggs are passed in the faeces and ingested by the intermediate host. This leads to cyst formation in the tissues and it is these cysts which are then infective (usually through scavenging or predation). Canine Taenia spp. tapeworms are found throughout the UK in livestock intermediate hosts and with the exception of Taenia multiceps which can lead to central nervous system (CNS) signs in young ruminants (‘gid’), infection is well tolerated. Cysts however will lead to significant meat and offal condemnation with subsequent significant economic impact on farmers. Clients are more likely however to enquire about Taenia spp. treatment because segments have been seen in the faeces. These proglottids are very visible to clients and represent a good way for nurses to introduce the topic of tapeworm control.
E. granulosus continues to be endemic in Wales and the Western Isles of Scotland with likely additional foci in parts of England and Scotland. It is currently unknown to what extent canine infection is occurring. The HyData Project at the University of Liverpool is using coproantigen testing on canines alongside abattoir traceback studies to form a clearer picture of the distribution of the parasite in Britain. In the meantime, control measures should be focused on dogs that have a high risk lifestyle and known geographic risk. These measures include:
- Regular tapeworm treatments of at risk dogs: dogs with outdoor/off lead access in known endemic areas as well as any dogs with known access to raw offal and fallen livestock should be treated with a licensed praziquantel product as least every 6 weeks. There are examples of population groups in Wales and Asia where treatment of dogs every 3 months has reduced human hydatid disease over time (Craig, 2014), so this should be a minimum recommendation in dogs that may have access to fallen livestock due to being off lead but exposure is uncertain. Dogs producing tapeworm segments should be dewormed monthly as this will eliminate proglottid shedding and minimise transmission risk to ruminants.
- Prevention of access of dogs to ruminant carcasses and raw offal: raising awareness of the risks of tapeworm infections, unprocessed raw diets and encouraging dog owners to keep pets on leads around livestock pasture is vital to help prevent transmission.
- Anti-dog fouling campaigns: while UK county councils heavily promote responsible disposal of dog faeces by owners, it is also important that veterinary practices play a role in pet owner education, especially in rural areas and those around livestock.
- Freezing of meat and offal intended for raw consumption: raw diet feeding of dogs is increasing and while this trend is unlikely to reverse in the short to medium term, it is vital that raw meat and offal ingredients have been adequately frozen (-180C for at least 10 days) to render tapeworm cysts and other parasitic life stages inactive.
The role of the VN in client education
Parasite advice can be sought from a number of sources but clients frequently look to veterinary professionals for advice as they often have a strong bond with the practice and therefore trust and comply with the guidance given. Advice should not just be given when the client seeks it, instead veterinary professionals should aim to educate clients at any given opportunity be that over the phone, during a routine consultation or in dedicated parasite nurse clinics. A study in 2012 by Onepoll found that 25% of pet owners (2000 participants) would welcome conversations on parasite control (Gerrard, 2016). A client education evening conducted by passionate and enthusiastic VNs may be a good way to educate a number of clients on parasite control.
It is imperative advice is standardised across all staff, for example receptionists, VNs and veterinary surgeons, so the information is clear and unambiguous. Training should be provided to less experienced members of staff to ensure the delivery of advice is polished. Wild (2017) states that clients are more likely to comply with advice given if they feel confident the professional knows what they are talking about. While all members of staff can and should discuss parasite prevention, Tottey (2015) believes many clients feel more comfortable talking to a VN as they are perceived to be more approachable and have more time than a veterinary surgeon with a busy consulting list or a receptionist who is trying to answer the phone. VNs can undertake a training course by the Animal Medicines Training Regulatory Authority (AMTRA) to become a suitably qualified person (SQP/animal health advisor). This qualification enables VNs (or the holder) to prescribe and dispense certain anthelmintics dependent on the remit of their qualification (Ackerman, 2012).
In order to educate clients on the importance of minimising the faecal-oral transmission route and therefore the previously discussed parasites, effective communication is essential. This has been shown to increase client compliance which has several benefits including:
- The client obtaining an improved knowledge and understanding of the relevant parasites, their risks and control measures — both anthelmintics and environmental methods
- Improved health and welfare for the pet as a direct result of the client's increased awareness
- Strengthening of the client–practice bond
- Improved satisfaction and motivation for staff having known they have made a positive contribution to the pet and client's parasite protection (Ackerman, 2012).
There are several points to think about when communicating with clients which can help achieve clear communication, these are referred to as the 7Cs (Hedberg, 2016):
- Complex — keep the information simple, be mindful of the speed of speech, consider how language and accents may act as a barrier. Avoiding the use of medical jargon and Latin parasite names is recommended.
- Content — plan what will be discussed (deviation from this is natural but ensure all content is covered), consider the pitching level of the information
- Context — keep it relevant to the pet and client's individual circumstances
- Concentrate — ensure the room is quiet and free from distractions
- Courtesy — the VN should maintain a pleasant facial expression and open body language and be respectful of the client's opinions and views
- Consistency — standardise advice across all veterinary professionals in the practice. Group training sessions can assist with this
- Compassion — demonstrate empathy and understanding.
By keeping these factors in mind the VN can develop a structure for communication which is natural and personal to them.
How to have the conversation
Whether the client is attending the practice or calling for advice, it is vital their first impression is positive — first impressions really do count! If the client telephones, the front of house team should quickly and politely identify the client, the reason for calling and the most appropriate person to transfer the call to, if required. If attending for an appointment the veterinary surgeon or VN should familiarise themselves with the clinical history in order to greet the client and pet by name, the pet should also be given a fuss. This personal approach has been shown to increase the bond between professional and client. The room in which the information and advice will be delivered should be clean and tidy and external noise should be kept to a minimum to diminish any barriers to communication. Consideration should be given to the layout of the room, particularly the position of the table and any chairs; separation of the client and the professional by the table or standing while the client sits can have a subtle effect on communication. Moving the table to one side and sitting together can help achieve a discussion and conversation in which mutual decisions are reached.
A detailed history should be obtained, it is vital the VN balances asking questions, which is important as pertinent information is needed to assess parasite risk and formulate a plan, with listening closely to the client. Clients who feel their opinions have been heard and valued are more likely to act on the advice given. Utilisation of active listening is advocated as this enables the VN and client to ensure each have understood one another. (Ackerman, 2012; Loftus, 2012). A partnership should be created with the client at this stage and the consultation should be a discussion/conversation in which both parties speak and are heard. The reader is directed to the Cambridge-Calgary Consultation Model for further support on how to communicate with clients in this manner (Figure 3).
The following are examples of questions which could be asked (not exhaustive):
- Does the client use a parasite control plan? When was the pet last treated? And what product was used? This enables the VN to determine when the pet can be treated next and with what product. Drug interactions can occur so obtaining this information helps to prevent this.
- Has the pet had any previous reactions to treatment? These products should be avoided in order to increase compliance. If the pet always reacts to a product the client may develop a negative association with parasitic prevention.
- Does the client prefer a certain formulation or product? Do they feel competent and confident in administering the chosen product?
- Does the pet regularly go swimming or is he/she regularly bathed? The efficacy of certain products may be affected which again could lead to the client perceiving the product to be ineffective leading to poor compliance.
- Does the pet eat a raw unprocessed diet, scavenge or hunt? As discussed this increases the risk of Toxocara spp., E. granulosus and Taenia spp.
- Does the client have children or grandchildren? Or is the pet in frequent contact with children? A monthly anthelmintic should be advised to minimise the risk of human toxocarosis.
- Does the client have any other pets? It is important all the pets in the household are treated, including indoor animals, to minimise the spread of parasites within the home.
Holistic communication
Communication must be an adaptive process in which the veterinary professional adjusts and tailors their approach to the individual client. There are three main learning styles: visual, auditory and kinaesthetic, some people may also learn best via a combination of styles (MindTools, 2017). By using a variety of communication methods the VN can cater for all learning styles and therefore tailor the communication, which will further improve compliance.
For visual learners consider the use of written information to include: leaflets, handouts, diagrams and pictures. Auditory learners may prefer verbal communication or watching videos on how to administer a product. In comparison kinaesthetic learners may want to get involved and have a go, so demonstrations and asking the client to then have a practice with a ‘dummy’ product can be useful.
Conclusions
The VN plays an integral role in educating clients on the risks of endemic intestinal parasites and their transmission methods including the faecal-oral route. By communicating effectively with, listening to and educating clients VNs can develop and nurture a partnership with their clients to enable mutual decision making and subsequent compliance.
KEY POINTS
- Veterinary nurses play a vital role in the education of clients on the risks of endemic intestinal parasites and their transmission methods to include the faecal-oral route.
- Parasites transmitted by the faecal-oral route which present the greatest risk in the UK are: Toxocara roundworms, intestinal protozoa and tapeworms.
- Effective communication increases client compliance through greater knowledge/understanding, which in turn improves the health and welfare of the pet.
- Development of a partnership with clients enables mutual decisions to be reached, which improves compliance.