Plus-Hex CLINICAL production means raw diets have a greater risk of transmitting these parasites [ 5, 7 ]. As definitive hosts, dogs can shed Sarcocystis within their faeces. Clinical signs of infection, including weight loss, anorexia and neurological complications, do not present until infections are severe, so they can go undetected [ 18 ]. Consequently, faeces must be appropriately disposed of, and surfaces disinfected, while wearing personal protective equipment [ 39 ].
T. gondii is clinically significant in cats and also has the potential to affect canine health, causing neurological issues through transplacental transmission to the foetuses in pregnant bitches fed raw diets [ 7 ]. In rare cases, neurological signs can develop in adult dogs [ 42 ]. Considering this, the findings of van Bree et al. [ 29 ] highlight the need to consider parasites in discussions about raw diets, along with health checks for dogs on raw diets.
van Bree et al. [ 29 ] examined frozen feeds in their study. These feeds should prevent the transmission of Sarcocystis and T. gondii, as most parasites are unable to survive freezing. However, through their findings, van Bree et al. [ 29 ] identified a significant risk of parasitic transmission in unfrozen raw feeds. Within the veterinary practice, the storage and provision of raw diets should be discouraged [ 43 ]. To minimise pathogen transmission at home, VNs should educate owners on the correct storage of fresh meat in raw diets [ 19 ]. It may not be possible for owners to freeze their pet ' s diets, so other prevention measures will be important.
Despite a clear association between raw diets and parasites, there is a lack of research into the significance level of the risk [ 28 ]. Allan et al. [ 30 ] report the identification of H. heydorni in the bile of a dog with acute cholangiohepatitis, which stemmed from the patient ' s raw diet. Due to its uncommon presence, little is known about this parasite; however, literature suggests that it is becoming clinically important, causing anorexia and diarrhoea if left untreated [ 7, 30 ].
As raw diets increase in popularity, a rise in common and uncommon parasites should be expected, along with their related negative health effects [ 7 ]. Understanding the potential risks and explaining them to owners of pets fed a raw diet is vital to minimise negative health effects [ 28 ]. Although it would be unprofessional of VNs to dictate client choices and discourage raw diets, they should ensure owners are educated on parasites and aware of the increasing prevalence of uncommon species and the clinical signs that may result from an infection. In addition, owners should be encouraged to maintain preventative measures to maximise animal health and welfare.
Despite the common belief that a dog ' s diet should mimic the carnivorous preferences of their ancestors, domesticated dogs have evolved to thrive on starch alongside meat [ 44 ]. However, some raw diets can be imbalanced and improperly formulated, with excessive amounts of protein and carbohydrates, while lacking important minerals such as calcium [ 45 ]. This presents a risk of serious health complications including hyperthyroidism, osteopenia and hypovitaminosis D, as well as other nutritional deficiencies [ 46 ]. Veterinary practices could therefore expect to see an increase in such deficiencies and related conditions.
Köhler et al. [ 47 ] proposed the idea that hyperthyroidism might be seen in dogs fed a raw diet containing fresh or dried gullets including thyroid tissue. Twelve canine patients presented with signs of hyperthyroidism, including weight loss and elevated plasma thyroxine concentrations. Once a commercial diet was introduced, plasma thyroxine levels decreased and clinical signs ceased.
Although it is not possible for veterinary practices to test dietary components, due to time and expense, on occasion further investigation of an individual patient ' s diet may be necessary. Alternatively, dietary histories can assist in the diagnosis and management of nutritionrelated conditions such as hyperthyroidism.
In a separate study, Zeugswetter et al. [ 48 ] examined a raw diet suspected of causing hyperthyroidism in two canine patients. After examination, it was confirmed that the meat had elevated iodine concentrations, affecting the health of its recipients. Reflecting the findings of Köhler et al. [ 47 ], a dietary change resolved each patient ' s health complications.
As VNs are viewed by clients as being approachable, VN-led dietary clinics can be helpful in providing clients with basic information on balanced and appropriate nutrition for their pet, to minimise the negative effects of raw diets [ 19 ]. Therefore, where time and resources permit, dietary clinics should be made more widely available to clients.
Ingredient lists for homemade diets, which are commonly sourced from books or the internet, often prove to be incomplete and imbalanced. This can result in vitamin and calcium deficiencies and the risk of nutrition-related conditions [ 36, 45 ]. Hall et al. [ 33 ] presented a case highlighting the effects of a nutritionally imbalanced homemade raw diet. The dog presented with osteopenia, severe hypovitaminosis D, hypocalcaemia, hyperparathyroidism, hypovitaminosis A and hypothyroidism. In a separate study, Dodd et al. [ 35 ] presented a case of a puppy with similar clinical signs and diagnosis to the case of Hall et al. [ 34 ], including calcium, vitamin D and phosphorus deficiencies, contributing to secondary hyperparathyroidism, hypovitaminosis D and osteopenia. From 9 weeks of age, the puppy had been maintained on a raw diet developed from a formulation in a pet recipe book.
Although case histories depend on client compliance and memory, the findings of Hall et al. [ 33 ] and Dodd et al. [ 35 ] highlight the importance of gaining a dietary
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