**Author details**

#### Joyce Siwila

**6. Treatment**

48 Current Topics in Giardiasis

**7. Conclusions**

These loses translate into food loses.

Treatment of giardiasis in livestock is through use of fenbendazole and albendazole, which have been shown to be effective in the elimination of *Giardia* from both housed and range calves [32, 127–129] as well as improving the mucosal microvillus structure and function within a week [129]. In sheep, treatment with fenbendazole at a dose of 10 mg/kg for three consecutive days, has been shown to successfully clear the infection. In an outbreak of giardiasis on a sheep farm, *Giardia*-infected lambs (30–90 days of age) presenting with malabsorption, decreased weight gain, and reduced feed efficiency recovered rapidly from the symptoms and poor weight gain after treatment with fenbendazole [69]. Similarly, in calves experimentally infected with *G*. *duodenalis* and treated with fenbendazole, a significant difference in weight gain was noticed between fenbendazole-treated and untreated calves. Animals in the treatment group gained on average 2.86 kg (equal to 102 g per day) more than the animals in the control group [27]. However, in some other treatment studies where fenbendazole or paromomycin sulphate were used, differences in mean body weight, average daily weight gain, or feed intake between the control and treated groups were not significant, although there was a slightly higher weight gain and lower occurrence of diarrhoea in the treated groups [12, 42]. In dogs and cats, fenbendazole is the commonly used therapy, normally given once daily for 3–5 days. Albendazole can be used but it has been associated with bone marrow suppression in both dogs and cats, and so no longer being used in both animal species [130]. Vaccines for *Giardia* in dogs and cats have been developed and they are reported to have the ability to reduce the duration of shedding of cysts which may subsequently reduce environmental contamination [131]. A prolonged treatment up to 5 days was shown not to be statistically better than treatment for three consecutive days [132]. On the other hand, metronidazole has been used to treat giardiasis in horses, with resolution of clinical signs after treatment [112].

*Giardia* infections are prevalent in livestock and companion animals. A number of studies have reported and genotyped *Giardia* in domestic animals, particularly livestock and companion animals, and have found that they may be infected with zoonotic or species-specific genotypes. However, there is still limited information on infection rates in pigs and horses. Further, the role of these animals and dogs in the zoonotic transmission of *Giardia* still needs further investigation. Studies reporting the existence of zoonotic assemblages in both animals and humans in the same locality (e.g. for dogs) emphasise the need for further studies on zoonotic transmission of *Giardia*. Such information will assist in further highlighting the public health significance of *Giardia*. Increased interaction and the nature of the interaction between companion animals and their owners can determine whether zoonotic infection occurs or not. Economic implications of the disease in terms of treatment costs that the farmers have to incur cannot be overlooked especially in livestock (particularly dairy calves). Giardiasis adversely affects production; and chronic cases may impact negatively on the performance of affected animals resulting in reduced weight gain, impaired feed efficiency and delayed maturity. Address all correspondence to: siwilaj@yahoo.co.uk

Department of Clinical Studies, University of Zambia School of Veterinary Medicine, Lusaka, Zambia
