If treatment is repeatedly unsuccessful , further investigation may be beneficial , as Giardia may not be the primary cause of the clinical signs . For example , inflammatory bowel disease ( IBD ) and allergies may be a factor . In some cases of prolonged parasitic infections , the gut flora is likely to be disrupted , which could lead to the continuation of the clinical signs .
Treatment
A current treatment recommendation is fenbendazole 50 mg / kg q24h for 3 days , but it is not uncommon for the prescribing veterinary surgeon ( VS ) to use this off-licence for up to 5 days [ 5 ] . The European Scientific Counsel Companion Animal Parasites ( ESCCAP ) states that it may be used initially for up to 10 days [ 6 ] . Metronidazole can be used at 25 mg / kg q12h for 5 days [ 5 ] . Care should be taken when prescribing metronidazole , due to the potential neurotoxicity that can occur in some cases . Antimicrobial resistance is another factor to be considered .
Other products have also been shown to treat Giardia cysts , including ronidazole and azithromycin , but these are not standard treatment recommendations . Moron-Soto et al . [ 7 ] suggested a dose of 15 mg / kg febantel , 5 mg / kg praziquantel and 14.4 mg / kg pyrantel for 3 consecutive days . Ciuca et al [ 5 ] stated that no patient tested negative after initial treatment , and it took two cycles to achieve 100 % efficacy of treatment . This should be considered , as reinfection after primary treatment is probable [ 5 ] . Explaining this to clients may aid in reducing frustration if treatment is initially unsuccessful .
Nitazoxanide is an antiprotozoal treatment commonly used in human medicine for the treatment of giardiasis and cryptosporidiosis . In dogs , Moron-Soto et al . [ 7 ] showed treatment with a single dose of nitazoxanide at 75 mg / kg to be as effective in cyst reduction as a commerically available febantel / praziquantel / pyrantel combination formulation ( Drontal Plus , Bayer Animal Health ) administered daily over 3 days . Single dosing was preferable , but further testing would be needed in animals [ 7 ] . Many dose ranges and treatment lengths may be off licence or not covered by manufacturers ' guidelines , so careful practitioner judgement should be used in each case .
The synergistic use of probiotics is thought to assist in the reduction of clinical signs . Metronidazole has an effect on microbial structures and diversity [ 5 ] , which makes it important to aid the gut flora during the treatment process . Increasing fibre with the use of products containing psyllium husk may help in reducing diarrhoea and other gastrointestinal disorders .
VNs can take a holistic approach to patient care and select the product that most effectively meets the needs of the individual patient . Probiotics containing vitamin B12 may also be beneficial in these cases . If malabsorption is diagnosed , cobalamin should be monitored in these cases . The use of hydrolysed protein-based food may also aid in the reduction of gastrointestinal signs , especially if dysbiosis or IBD is a differential diagnosis . The VN can discuss dietary options with the client and can also advise on diet trials .
Bathing of patients with a chlorhexidine-based shampoo during the treatment process is also recommended to reduce the likelihood of reinfection via the animal ' s fur . This may be done at the start of treatment , on completion and at regular intervals in the weeks afterwards to reduce the likelihood of reinfection .
In some cases , clipping the urogenital region before bathing the animal may further reduce the presence of cysts on the fur . It may be advisable for the owner to arrange a consultation with a VN to discuss clipping and bathing the patient to reduce the risk of patient injury .
In multi-pet households , all animals living in close proximity may have giardiasis , with or without the presence of clinical signs . It is therefore important to consider the treatment and bathing of all animals to reduce the risk of reinfection . Treatment of subclinically infected individuals is not always recommended , due to the risk of drug resistance , but withholding treatment is not indicated in multi-pet households [ 8 ] . Veterinary professionals should explain to owners the importance of compliance with hygiene protocols and the treatment of all animals in a multi-pet household , to gain the best outcome for the patient .
Environmental factors
Good hygiene protocols include picking up faeces in the pet ' s environment and preventing animals from eating faeces . Disinfecting soiled areas of the household thoroughly will also reduce the risk of reinfection . However , it may not be possible to disinfect all areas of the garden , such as grass . Giardia cysts may survive for several months in the environment , especially in cold damp weather . Soil moisture in vegetated areas increases the risk of finding Giardia cysts [ 9 ] . The use of bleach and quaternary ammonium compounds ( QACs ) on grass is futile [ 9 ] , but QACs are useful in the reduction of household cysts , with 90 – 99 % efficacy [ 10 ] . QACs may be less damaging to surfaces than other products , such as hydrogen peroxide , but some may be toxic to aquatic animals , and the manufacturer ' s guidelines should always be followed .
VNs should suggest appropriate products to meet the client ' s needs , and should advise them to follow common safety guidelines – such as allowing ample ventilation of the disinfected area , and waiting for products to dry completely before returning animals – in addition to the manufacturer ' s guidelines .
10 Veterinary Nursing Journal