Canine giardiosis in an urban are Title source on infection of man. NikoliĆ, Aleksandra, DimitrijeviĆ Author(s) BobiĆ, Branko

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1 ' ' Canine giardiosis in an urban are Title source on infection of man NikoliĆ, Aleksandra, DimitrijeviĆ Author(s) BobiĆ, Branko The Journal of Protozoology Resea Citation Issue Date URL Rights 帯広畜産大学学術情報リポジトリ OAK:Obihiro university Archives o

2 J. Protozool. Res. 11, (2001) Copyright 2001, National Research Center for Protozoan Diseases Canine giardiosis in an urban area: a possible source on infection of man 1 Aleksandra Nikoli*, 2 Sanda Dimitrijevi2, and 1 Branko Bobi 1 Department of Parasitology, Institute for Medical Research, Belgrade, Yugoslavia 2 Institute for Preventive Veterinary Medicine, Department of Parasitology, School of Veterinary Medicine, University of Belgrade, Yugoslavia Key words: Giardia lamblia, dogs, prevalence, urban area *Corresponding author; A. Nikoli, Institute for Medical Research, Dr. Subotica 4, P.0. Box 102, Belgrade, Yugoslavia Phone: 381 (11) Fax: 381 (11) sasan@imi.bg.ac.yu ABSTRACT Giardia lamblia is a commonly identified intestinal pathogen protozoan in humans in Serbia, since 8.0% of the children are infected in Belgrade area. In light of the zoonotic potential of Giardia infection, a total of 167 dogs were examined for giardiasis in the same urban area. Six of 81 dogs (7.4%) from urban homes, 14 of 75 dogs (18.6%) from the pound, and four of 11 dogs (36.4%) from the farm were excreting Giardia cysts. Thus, the overall prevalence of infection in dogs in the Belgrade area was 14.4%. Of six household pets excreting Giardia, five owners and all 16 of their family members were Giardia-negative, while in case of one dog both the owner and the only other family member were Giardia- positive. The data demonstrate that a potential animal reservoir exists in urban Serbia and underline the possibility of transmission between dog and human in close contact, thus having important implications for the epidemiology of giardiasis in urban areas. INTRODUCTION Giardia lamblia is one of the most prevalent human intestinal parasites found worldwide. Cases of giardiasis in man are steadily increasing (Kappus et al. 1994). Giardia is now 61

3 62 considered to be the leading intestinal parasite in Serbia (Nikoli et al. 1996), since 6.8% of children in urban areas are infected, especially in the Belgrade area (8.0%). This arose an increased interest in the study of all aspect; of Giardia, particularly whether or not giardiasis exists as a zoonosis. Several studies suggested that some water-borne epidemics of giardiasis in the USA were of zoonotic origin (Dykes et al. 1980). As Giardia has the widest host range and has been frequently found in several species of animals, wild and domestic, as well as in household pets, it is commonly assumed that human infection can be acquired from other mammalian hosts and vice versa. Despite the potential public health significance of animal reservoirs of Giardia, the results of only one survey in Serbia have been published (Nikoli et al. 1993). To assess the possible role of dogs in the epidemiology of giardiasis in urban areas, the present investigation was carried out to establish the prevalence of infection in dogs in Belgrade, and to examine pet dog owners for giardiasis. MATERIAL AND METHODS In the present study we sampled 81 household pets attending the Belgrade Veterinary School Clinic for a variety of reasons, 75 stray dogs admitted to the Belgrade City pound, and 11 dogs housed at the Military Dog Farm in Belgrade, none of which showed signs of clinical giardiasis (diarrhea). A single stool specimen was collected from each of 167 dogs. All samples were examined by direct saline smear, Lugol stained smear and the zinc sulphate concentration technique, primarily for Giardia cysts, but also for the presence of other parasites. When Giardia cysts were found in the faeces of pet dogs, the owners as well as their family members were examined for Giardia excretion by the same methods. All stools were examined within 48 hours. If there was a delay more than three hours after collection, the stools were refrigerated. RESULTS AND DISCUSSION Six of 81 dogs (7.4%) from urban homes, 14 of 75 dogs (18.6%) from the pound, and four of 11 dogs (36.4%) from the farm were excreting Giardia cysts (Table 1). Thus, the overall 62

4 63 prevalence of infection in the Belgrade area was 14.4%. A previous study carried out by our group involving only household pets demonstrated a much lower prevalence of infection (3.8%) in the same area (Nikoli et a ). While it is true that Giardia cysts are often shed intermittently, and an examination of a single sample may result in false negatives and a low prevalence estimation (Hiatt et a ), there is no reason to believe that a particular group (i.e. farm dogs, stray dogs etc.) was more affected. Giardia was more frequently detected in stray and farm dogs than in household pets. Those results are in accordance with Swan and Thomson (1986), who also found that stray dogs had Giardia more often than pet dogs (30% vs. 9%). Moreover, infection was significantly more frequent in farm dogs than in stray dogs. While the stray dogs resided together in the pound only for a few days (1-3) before examination, the longer period of close contact among farm dogs sharing living quarters may account for a higher prevalence of infection in these. Similar observations were recorded by Burnie et al. (1983). In their study, the prevalence of infection increased from 4% upon admission to the kennels, to 12% when the dogs were sampled seven days later. There was no evidence that Giardia was associated with the presence or absence of other intestinal parasites, similar to what has been noticed by Sykes and Fox (1989). In stray and farm dogs, intestinal parasites detected included Trichuris (80.2%), Ancylostoma (40.7%), Toxocara (25.6%) and Taenia (10.5%). While the overall prevalence of infection with other intestinal parasites amounted to 91.9%, they were detected in 88.9% samples of the Giardia-positive dogs and in 92.6% samples of the Giardia-negative ones (p>0.05). Since none of the stray and farm dogs in our series received anthelminthic treatment, it is not unexpected that helminthic infections were significantly (p<0.001) more frequent (78%) than both protozoan (2%) and combined protozoan-helminthic infections (20%). In contrast, in household pets with regular anthelminthic prophylaxis, protozoa, in particular Giardia, were detected more frequently than helminth parasites. Of six household pets excreting Giardia, five owners and all 16 of their family members were negative for Giardia, while in case of one dog both the owner and the only other family member were Giardia-positive. Notably, both household members had diarrhoea for some weeks 63

5 64 before examination. Following metronidazole treatment of both patients and the dog, all clinical signs and symptoms subsided, and repeated examination of three consecutive stool samples was negative for Giardia cysts. This finding underlines the possibility of transmission between dog and man in close contact. This study was the first assessment of the infection rate of Giardia in stray dogs in one Serbian urban area. The finding of a high rate of infection suggests that stray dogs may be a source of environmental contamination by Giardia cysts for urban pet dogs, particularly if dogs are susceptible only to the canine strain of Giardia (Woo & Paterson 1986; Monis et al. 1998). Moreover, since it has been suggested that humans may be susceptible to both strains (Faubert 1988), people in close contact with pet dogs may be exposed to Giardia cysts of canine origin. Thus, stray dogs may also be responsible for further transmission to human. Therefore, the results of this study demonstrate that a potential animal reservoir exists in urban Serbia and future work should focus on the genetic structure of Giardia populations in dogs and humans. Table 1. Prevalence of Giardia in dogs in Belgrade area No. examined No. infected (%) Household pets 81 6 (7.4) Stray dogs (18.7)* Farm dogs 11 4 (36.4)**# Total (14.4) Statistical significance as shown by the chi square test: *p<0.05, **p<0.001 compered to household pets; # p<0.05 compared to stray dogs. ACKNOWLEDGEMENTS Serbia. This work was supported by a grant from the Ministry of Science and Technology of REFERENCES Burnie, A.G., Simpson, J.W., Lindsay, D. & Miles, R.S The excretion of campylobacter, salmonellae and Giardia lamblia in the faeces of stray dogs. Vet. Res. Commun. 64

6 65 6: Dykes, A.C., Juranek, D.D., Lorenz, R.A., Sinclair, S., Jacubowski, W. & Davies, R Municipal water-borne giardiasis: an epidemiological investigation. Ann. Intern. Med. 92: Faubert, G.M Evidence that giardiasis is a zoonosis. Parasitol. Today 4: Hiatt, R.A., Markel1, E.K. & Ng, E How many stool examinations are necessary to detect pathogenic intestinal protozoa? Am. J. Trop. Med. Hyg. 53: Kappus, K.D., Lundgren, R.G. Jr., Juranek, D.D., Roberts, J.M. & Spencer, H.C Intestinal parasitism in the United States: update on a continuing problem. Am. J. Trop. Med. Hyg. 50: Monis, P.T., Andrews, R.H., Mayrhofer, G., Mackrill, J., Kulda, J., Isaac-Renton.J.L. & Ey, P.L Novel 1ineages of Giardia intestinalis identified by genetic analysis of organisms isolated from dogs in Australia. Parasitology 116:7-19. Nikolic', A" Kulisic, Z. & Bojkovski, J Giardiasis as a zoonosis: the prevalence of Giardia in dogs in Belgrade. Acta Vet. 43: Nikolic', A., Djurkovic-Djakovic, O., Bobic, B. & Vukovic, D Intestinal parasitism in schoolchildren in Serbia. Significance of rural vs. urban environment. Arch. Gastroenterohepatol. 15: Swan, J.M. & Thomson, R.C.A The prevalence of Giardia in dogs and cats in Perth, Western Australia. Aust. Vet. J. 63: Sykes, T.J. & Fox, M.T Patterns of infection with Giardia in dogs in London. Trans. R. Soc. Trop. Med. Hyg. 83: Woo, P.T.K. & Paterson, B.W Giardia lamblia in children in day-care centers in southern Ontario, Canada, and susceptibility of animals to G. lamblia. Trans. R. Soc. Trop. Med. Hyg. 80: