Prevalence of Giardia species in stool samples by ELISA in household cats from Romania and risk factors

Abstract

Stool samples (n=183) collected in Romania from cats of different ages, gender, breed, living conditions and origin were analysed by enzyme-linked immunosorbent assay using a commercial kit (Giardia Microwell ELISA, SafePath Laboratories, Carlsbad, USA). Fifty-one cats (27.9%) presented Giardia duodenalis antigens. The prevalence was significantly higher in cats with diarrhoea (32%, 16/50; P=0.04) and in cats from the north-west region (36.7%, 29/79; P=0.05). Young age (up to 6 months) was identified as the risk factor for infection (OR=0.29, 95% CI 0.09–0.92; P=0.03). There weren't any significant differences associated with gender, breed, medium, lifestyle, associated parasite infections, anthelmintic treatments, type of food or season.

Giardia duodenalis is one of the most common enteric parasites of domestic dogs and cats. Giardia species has been detected in cats worldwide with a prevalence ranging from 0% to 80%.^1,2 However, it has been suggested that the prevalence of Giardia species in companion animals is often underestimated because of the low sensitivity of conventional detection methods, and because the parasite may be present at subclinical levels and the cysts are excreted intermittently.^1,3 Although Giardia species is common in cats, it is rarely associated with clinical disease in these animals. However, if clinical giardiasis is reported, it is usually associated with cattery situations, where the effects of overcrowding may cause stress and exacerbate the effects of an infection.⁴

Molecular epidemiological studies have shown that cats may be infected with their own, host-adapted assemblage of Giardia species,^5–8 as well as with zoonotic assemblages,^8–11 which may be reservoirs for parasites and a source of infection for humans.^12,13 Under these conditions, the treatment of giardia-infected cats is usually recommended, whether or not they are clinically ill, because of the potential for zoonotic transmission.

The objective of this study was to estimate the prevalence of G. duodenalis infection in household cats in Romania by enzyme-linked immunosorbent assay (ELISA), and afterwards to evaluate the associated risk factors for infection.

Materials and methods

Cats in the survey

During a period of 2 years (2007–2009), faecal samples were collected from 183 household cats (100 females and 83 males) aged from 4 months to 17 years (mean±SD=3.56±3.29 years). Cats were from 12 counties (rural=55 and urban=128 area) in three regions of Romania. All the cats, except those presented to the Internal Medicine Department for digestive disorders, were clinically healthy. Sixty-five cats had an entirely indoor lifestyle and 118 had outdoor access. The majority of the cats were common European Shorthairs (n=142) and the remaining were purebred (16 Birman, 10 Persian, nine Siamese, two Balinese, three Prussian Blue and one Blue British Shorthair). Information on age, breed, gender, habitat, lifestyle, season, region, prophylactic anthelmintic treatments and associated parasite infections was registered for each cat. Also, the presence or absence of diarrhoea and food type was registered, but only for 117 and 118 cats, respectively.

Samples

Faecal samples were collected once from each cat. From outdoor and rural cats the faecal samples were obtained after isolation in cages and treatment with a laxative (lactulose syrup, 2–5 ml/cat). Seventy-eight samples were obtained by cat owner's submission, 50 by the veterinarian at the Department of Internal Medicine and 55 by the veterinary students in rural areas.

The stool samples were placed in containers labelled with identification data and sent to the Parasitology and Parasitic Diseases Department (Faculty of Veterinary Medicine Cluj Napoca, Romania) and kept at −70°C until processing. They were assayed by ELISA using a commercial kit (Giardia Microwell ELISA, SafePath Laboratories, Carlsbad, USA), following the manufacturer's instructions, in order to detect G duodenalis specific antigens in faeces.

Analysis of data

Frequency, prevalence and its 95% confidence interval (CI) of Giardia species infection were established. These parameters were determined by age, gender (male and female), breed (crossbred or purebred), lifestyle (indoor or outdoor), habitat (urban and rural), season (winter and spring), region (centre, south-west and north-west), diarrhoea (yes or no), infection with other parasites (yes or no), type of food (dry food, mixed food) and prophylactic anthelmintic treatments (yes or no). Age categories included kitten (0–6 months), juvenile (>6–12 months) and adult (>12 months) were also analysed. Risk factors were analysed by univariate analysis using the χ ² test and by multivariate logistic regression models. Risk was expressed as an odds ratio (OR) with 95% confidence interval. A P value of <0.05 was statistically significant. All statistics were performed using the EpiInfo 2000 software.

Results

Prevalence rates in Giardia species-positive household cats are shown in Table 1. Fifty-one out of 181 faecal samples (27.9%) presented with Giardia species antigens. The prevalence was significantly higher (P=0.04) in cats with diarrhoea (16/50; 32%) compared to cats without diarrhoea (11/67; 16.4%). Also, a significant difference (P=0.05) was noticed between regions, being higher in the north-west of Romania (29/79; 36.7%). Even when no other statistically significant differences were observed, prevalence of Giardia species infection was higher in kittens, males, cats from rural areas, those with mixed parasite infections, those without any prophylactic anthelmintic treatments, those fed with mixed food and in the winter season. Multivariate analysis indicated a Giardia species infection risk for young age (OR=0.29, 95% CI 0.09–0.92; P=0.03).

Table 1.

Frequency and prevalence (95% CI) of Giardia species infection by ELISA (copro-antigens) in household cats from Romania

	Total samples	Number of positive samples	Prevalence (95% CI)	P
Total	183	51	27.9 (21.5–35)
Age
≤6 months	13	7	53.8 (25.1–80.8)^∗	0.07
>6 months to ≤12 months	36	11	30.6 (16.3–48.1)	0.07
>12 months	134	33	24.6 (17.6–32.8)
Gender
Males	83	26	31.3 (21.6–24)	0.34
Females	100	25	25 (16.9–34.7)
Breed
Crossbred	142	41	28.9 (21.6–37.1)	0.57
Purebred	41	10	24.4 (12.4–40.3)
Type of food
Dry food	51	10	19.6 (9.8–33.1)	0.46
Mixed food	67	17	25.4 (15.5–37.5)
Diarrhoea
Yes	50	16	32 (19.5–46.7)^∗	0.04
No	67	11	16.4 (8.5–27.5)
Mixed infection
No	127	31	24.4 (17.2–32.8)	0.1
Yes	56	20	35.7 (23.4–49.6)
Protozoa
No	168	45	26.8 (20.3–34.2)	0.2
Yes	15	6	40 (16.3–67.7)
Helminths
No	133	37	27.8 (20.4–36.3)	0.87
Yes	50	14	28 (16.2–42.5)
Anthelmintic treatments
No	69	24	34.8 (23.7–47.2)	0.1
Yes	114	27	23.7 (16.2–32.6)
Number of anthelmintic treatments/year
0	69	24	31.8 (23.7–47.2)	0.08
1	14	3	21.4 (14.7–50.8)
2	30	11	36.7 (19.9–56.1)
3	29	8	27.6 (12.7–47.2)
4	41	5	12.2 (4.1–26.2)
Habitat
Urban	128	33	25.8 (18.5–34.3)	0.34
Rural	55	18	32.7 (20.7–46.7)
Lifestyle
Indoor	65	19	29.2 (18.6–41.8)	0.76
Outdoor	118	32	27.1 (19.3–36.1)
Season
Winter	55	19	34.5 (22.2–48.6)	0.18
Spring	128	32	25 (17.8–33.4)
Region
Centre	29	5	17.2 (5.8–35.8)	0.05
North-west	79	29	36.7 (26.1–48.3)	0.05
South-west	75	17	27.7 (13.8–33.8)

Multivariate logistic regression models: ∗P<0.05.

Discussion

In the present study we obtained a prevalence of Giardia species infection in cats from Romania of 27.9% by ELISA. In a previous study we registered a prevalence of 0.7% by sodium chloride flotation followed by microscopy.¹⁴ The prevalence of Giardia species in cats in the world varies with the method of detection, cat population (household, shelter, stray), number of cats studied and geographical area, and because of this it is difficult to compare the data. Briefly, the prevalence ranges between 0% and 80%.

Our prevalence is comparable with other data reported in European countries such as Belgium (26.32%) and Germany (24.59%),¹⁵ and higher than in countries such as Spain (14.59%), France (15.31%), Italy (17.71%), The Netherlands (13.2%) and United Kingdom (11.54%).¹⁵ The difference between our study and the above cited one it is that Epe et al¹⁵ studied symptomatic cats by Snap Giardia Test, and in our case there were both asymptomatic and symptomatic cats. In symptomatic cats, we noticed a higher prevalence (32%) and in asymptomatic cats a lower prevalence (16.4%).

Moreover, the prevalence is usually higher in stray and shelter cats than in household ones. Taking this finding into account, our prevalence is higher than in Europe, using the same method (ELISA). For example, in household cats a prevalence of 12.6% was reported in Germany,¹⁶ of 13.8% in Italy¹⁷ and of 13.6% in The Netherlands⁸ and a higher one in shelter cats (22.4%) in Germany.² It is possible that the higher prevalence in our study could be due to the kit used. We used a commercial kit recommended for animal faeces (Giardia Microwell ELISA, SafePath Laboratories, Carlsbad, USA) and the cited authors used a human commercial kit (ProSpecT, Alexon-Trend, USA). According to molecular epidemiology studies reported in cats up to now, most of the assemblages are cat specific^6,18 and this partially explains the different results obtained by us. A similar explanation was proposed for Cryptosporidium species in dogs by Hopkins et al¹⁹ and Rimhanen-Finne et al³ The kit used by us is based on polyclonal antibodies (microtitre plate coated with anti-Giardia species rabbit polyclonal antibodies), while the human kit (ProSpecT) uses monoclonal antibodies that bind GSA 65, a soluble Giardia species-specific antigen.

Young age (≤6 months) was identified by multilogistic regression model as the only risk factor associated with Giardia species infection in household cats. No association was found with gender, breed, habitat, lifestyle, associated parasite infections, anthelmintic treatments, type of food and season. These results are in accordance with previous results reported by various authors.^17,20,21 In most of the studies, the prevalence of Giardia species infection was reported to be significantly higher in young animals, especially in 6-month-old cats.^17,22–24

Even if our study is limited to the epidemiology of Giardia species infection in cats without molecular typing of the isolates, the results are useful at least for veterinarians. They should counsel owners on the risks of humans acquiring protozoal infections from their cat(s), especially in households with young children, pregnant women, or immunocompromised individuals. Further investigation is needed in order to check for Giardia species assemblages in Romanian cats.

Footnotes

Acknowledgments

The samples were collected for grant PNII PC 51-013/2007 (Surveillance improvement of Toxoplasma gondii infection in some animals species and humans, as a public health problem in centre and western Romania) financed by the Ministry of Education, Research and Innovation and National Centre for Programme Management from Romania.

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