Issue
Parasite
Volume 21, 2014
Novel Approaches to the Control of Parasites in Goats and Sheep. Invited editors: Hervé Hoste, Smaragda Sotiraki and Michel Alvinerie
Article Number 45
Number of page(s) 7
DOI https://doi.org/10.1051/parasite/2014048
Published online 05 September 2014

© N. Tzanidakis et al., published by EDP Sciences, 2014

Licence Creative Commons
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Introduction

Giardia duodenalis and Cryptosporidium spp. are gastro-intestinal protozoa that affect a wide range of mammals. Both parasites have a direct life cycle and are known to cause enteritis. In small ruminants, mainly young lambs and goat kids are infected. The prevalence of both parasites in small ruminants varies considerably between studies worldwide [13]. The most common clinical symptoms associated with G. duodenalis are the excretion of malodorous, loose to diarrhoeic faeces and impaired weight gain, whereas Cryptosporidium spp. infection can lead to severe diarrhoea, depression, anorexia and weight loss [1, 12]. Mortality has been associated with cryptosporidiosis, especially in animals with concurrent infections.

Since the initial claims on its potential public health relevance, eight genotypes or so-called assemblages have been identified within G. duodenalis [25]. Assemblage A and B are considered to be zoonotic genotypes, affecting both humans and small ruminants [1, 12, 16, 23], whereas Assemblage E is considered to be specific to hoofed livestock and has been found to be the most prevalent assemblage in lambs and goat kids [8, 12]. The genus Cryptosporidium consists of 20 species and more than 40 genotypes. In sheep, C. parvum, C. xiaoi and C. ubiquitum are most frequently identified [9, 12, 27, 29, 35, 41] whereas mainly C. parvum and to a lesser extent C. xiaoi has been reported in goats [9, 12, 35]. Due to the potential clinical and zoonotic relevance, there is a need to better understand the presence and abundance of both parasites in sheep and goat flocks.

The aim of this study was to estimate the prevalence of G. duodenalis and Cryptosporidium spp. infection in sheep and goat dairy farms in Greece. The small ruminant sector is very important in the Mediterranean basin from an economic, social and ecological point of view [5], especially in Greece with approximately 15 million sheep and goats which are kept traditionally for milk under low-input systems [20]. The most commonly applied farming systems practised in Greece can be categorized as extensive farming [43], and there is limited information on prevalence and especially molecular characterization of both parasites in these systems. The prevalence rates reported range from 33.3% to 49.6% for G. duodenalis and from 4.4% to 55% for Cryptosporidium spp. in sheep and goats [21, 32].

Materials and methods

Study design

The study was designed as a cross-sectional study in a high sheep and goat density area in Greece (i.e. the island of Crete where more than 1.5 million animals are kept). The farms enrolled in this survey were selected according to the following criteria: (a) type of animal on the farm (sheep, goats, or mixed sheep and goats), and (b) management practices applied (“intensive management system” where stocking rates are high and the young animals are reared indoors until weaning (30–40 days), and “extensive management system” where stocking rates are lower and young animals are reared with their mothers mostly on pasture). Each farm was visited on a single occasion in a 6-month period, and only animals between the age of 1 day and 10 weeks were considered for inclusion in the study. Sample size was calculated based on the number of expected births as an indicator of the number of animals on the farms: of the lambs, 5% of the expected births on each farm were sampled and of the goat kids, 10% of the expected births were sampled. Data on the type of water supply for the animals (public network supply, a private drill hole or natural well), the age of lambs or goat kids and the presence of diarrhoea were recorded.

Parasitological examination

The faecal samples were examined in the laboratory using a quantitative immunofluorescence assay (IFA; Merifluor Cryptosporidium/Giardia kit; Meridian Diagnostics Inc.), as follows: 1 g of faeces was suspended in tap water and sieved three times through a layer of surgical gauze to withhold large debris. Sedimentation for at least 30 min was followed by discarding the supernatant. The remaining sediment was centrifuged at 3000 rpm for 5 min. The sediment was re-suspended in 1 mL of tap water. After thorough vortexing, an aliquot of 20 μL was applied onto an IFA slide. The samples, including a negative and positive control sample, were left to dry completely. After staining and incubating slides in a dark humidified chamber (for 30 min at room temperature), the entire slide was examined at 400× magnification under a fluorescence microscope. A sample was considered positive if at least one, clearly recognizable Cryptosporidium oocyst or Giardia cyst was identified. The number of (oo)cysts per gram of faeces was obtained by multiplying the total number of (oo)cysts on the slide by 50.

Molecular characterization

Positive isolates for both parasites were selected for DNA extraction, using the QIAamp Stool Mini Kit (Qiagen), according to the manufacturer’s instructions, incorporating an extended initial step of five freeze-thaw cycles (freezing in liquid nitrogen for 5 min and heating at 95 °C for 5 min) in the protocol to maximize (oo)cyst lesion. The selection of the positive isolates aimed to include at least one positive sample per farm.

For the amplification of the Cryptosporidium spp., the 18S ribosomal DNA (18S rDNA) gene PCR protocol was used (previously described in [40]), as well as a PCR targeting the 70 kDA heat shock protein (HSP70, described in [28]). Subgenotyping of the C. parvum positive samples was performed using the 60 kDa glycoprotein (gp60) gene [34]. G. duodenalis positive samples were characterized using the β-giardin gene [24], and the triose phosphate isomerase (TPI) gene [11]. Amplification products were visualized on 1.5% agarose gels with ethidium bromide. A positive and negative (PCR water) control sample was included in each PCR. PCR products were purified using the Qiaquick purification kit (Qiagen) and fully sequenced using the BigDye Terminator V3.1 Cycle Sequencing Kit (Applied Biosystems). Sequencing reactions were analysed on a 3100 Genetic Analyzer (Applied Biosystems) and assembled with Seqman II (DNASTAR, Madison, WI, USA). Sequences were compared with known sequences by BLAST-analysis against the NCBI database.

Results

A total of 21 farms with either a sheep (n = 7) or goat (n = 7) flock, or a mixed sheep and goat flock (n = 7) were visited. On the majority of the farms (14/21) animals were reared under the intensive management system, whereas on 7 farms, goats and sheep were reared under the extensive management system (Table 1). In total, 684 faecal samples were examined, of which 429 samples were from lambs and 255 from goat kids. Mean lamb age was 5 weeks (range 4–8 weeks) and mean goat kid age was 6 weeks (range 4–9 weeks).

Table 1.

Overview of the 21 farms included in the study, with the number of sheep and/or goats on the farms (N) and the type of management system (Sampled = number of animals sampled on each farm).

The prevalence of G. duodenalis was 37.3% (n = 160/429) in lambs and 40.4% (n = 103/255) in goat kids. In total, 13 out of the 14 farms (92.9%) with a sheep flock, and 14 out of the 14 farms (100%) with a goat flock, were positive for G. duodenalis with a minimum of 4 positive samples on each positive farm. The prevalence of Cryptosporidium spp. oocysts was 5.1% (n = 22/429) in lambs and 7.1% (n = 18/255) in goat kids. In total, 8 out of the 14 farms (57.1%) with a sheep flock, and 7 out of the 14 farms (50.0%) with a goat flock, were positive with a minimum of 1 positive sample on each positive farm.

Intensity of G. duodenalis cyst excretion ranged from 50 to 800,000 cysts per gram (cpg) of faeces in lambs with an average of 48,989 cpg, and from 50 to 900,000 cpg for goat kids with an average of 94,053 cpg. The excretion level for Cryptosporidium oocysts was low in lambs with an average of 9143 oocysts per gram of faeces (range 200–31,900 opg), yet was high in goat kids with an average excretion of 47,744 opg (range 200–551,000 opg).

A minimum of 1 positive sample was selected for DNA extraction per farm for G. duodenalis and Cryptosporidium spp., respectively. In total, 71 samples yielded a positive amplicon for G. duodenalis (Table 2). The majority of the samples were typed as a mono-infection with the ruminant-specific assemblage E, both on the β-giardin gene and the TPI gene. Only a limited number of samples were typed as mixed assemblage A and E infections, both in lambs and in goat kids. For Cryptosporidium, 24 samples yielded a positive amplicon (Table 3). Three different Cryptosporidium species (C. parvum, C. ubiquitum and C. xiaoi) were identified, although C. xiaoi was not identified in lambs. The C. parvum positive samples were typed as subtype IId on the gp60 gene (IIdA4G2T14 and IIdA4G3T13).

Table 2.

Results for molecular identification of Giardia duodenalis positive samples in goat kids and lambs, based on the B-giardin (= beta-giardin) or triose phosphate isomerase (TPI) gene (NA = no amplification; A = assemblage A; E = assemblage E; A + E = mixed infection with assemblage A and E).

Table 3.

Results for molecular identification of Cryptosporidium positive samples in goat kids and lambs.

Discussion

The present study illustrates that G. duodenalis is highly prevalent in both lambs and goat kids, as the parasite was detected in all but one of the sheep flocks and in all goat flocks. The high farm and animal prevalence is in line with previous studies in small ruminants in Europe [4, 13, 18]. The high G. duodenalis prevalence and the potential association with production losses [31, 44] require an appropriate level of awareness of this infection on those farms in terms of disease management and prevention of infection. In contrast to G. duodenalis, the prevalence of Cryptosporidium was lower than anticipated in both lambs and goat kids, probably due to the age range of the animals included in the present study. Nevertheless, the farm prevalence on the sheep (57.1%) and goat (50.0%) farms does suggest that Cryptosporidium is widespread and is a potential threat to the small ruminant population. In previous studies in Greece, Cryptosporidium has been associated with large outbreaks of diarrhoea in both sheep and goat flocks [14, 15, 37], similar to other major small ruminant rearing countries [6, 33].

Both for G. duodenalis and for Cryptosporidium spp. a potential public health threat has been suspected, based on the high prevalence of these parasites in small ruminants and on extrapolation of molecular insights from other animal species, such as cattle or companion animals. However, recent molecular data seem to suggest that small ruminants are mostly infected with non-zoonotic genotypes of G. duodenalis [12, 18, 38, 39, 46, 47] and Cryptosporidium spp. [38]. On the other hand, potentially zoonotic genotypes or species such as G. duodenalis assemblage A and B [1, 2, 12, 19, 26, 30, 41], C. parvum [3, 6, 12, 22, 46], C. hominis [17], C. meleagridis [42] and C. ubiquitum [10, 12, 45] have been reported in small ruminants. Furthermore, the identification of potentially zoonotic genotypes does not necessarily imply that transmission occurs. Recently, host-associated populations of C. parvum have been described using a multi-locus genotyping (MLG) approach, and C. parvum populations found in goats were even found to differ from bovine and sheep MLGs [7]. Whether this is a true host-specific phenomenon or just a matter of the level of isolation and opportunities for out-crossing is still to be discussed. Nevertheless, the contradicting molecular findings illustrate the difficulty of evaluating a potential public health threat based solely on genetic data without considering the epidemiological background and transmission of infection. Direct transmission of Cryptosporidium infection through bottle feeding or petting of animals on educational farms has been described before [38], but is probably an occasional route of infection. Although there is no direct evidence of transmission of Cryptosporidium and G. duodenalis infections from small ruminants to the human population via contaminated water, it is considered a threat. Furthermore, the detection of both parasites in outbreaks and in water screening is not routine practice in most countries, and large waterborne outbreaks might go unnoticed. In a recent study in Spain, the prevalence of Cryptosporidium and Giardia in water was significantly higher in the inland area, with higher concentration of livestock and fewer water treatment plants [4], illustrating that a variety of factors define the odds for infection. In the specific study area on the island of Crete, only a limited number of water basins are used over the island to produce drinking water for the local population and for the tourist population in the summer. The pastures surrounding the drinking water basins are all grazed by small ruminants. Whether these conditions lead to a substantial public health threat will need to be evaluated further in a longitudinal study, including sampling of water.

In goats, a large proportion of the Cryptosporidium positive samples were typed as C. xiaoi, both on 18S and HSP-70. This is in agreement with previous studies in Spain [6] and France [36], yet contradicts the initial claim that C. xiaoi infections are largely restricted to sheep [9]. In the current study, C. xiaoi was found in goats from three different farms, of which 2 farms maintained a goat-only flock and 1 farm managed a mixed flock. This illustrates that, although the introduction in the goat flocks might be due to contact with infected sheep, a C. xiaoi infection is easily maintained in goats. As advocated by Fayer and Santin [9], further epidemiological data will be needed to confirm whether the reports of C. xiaoi in goats are incidental or a regularly observed finding.

In conclusion, a high animal and farm prevalence of G. duodenalis, and a high farm prevalence of Cryptosporidium spp. were detected in both lambs and goat kids. Although mainly non-zoonotic species were identified in the present study, the frequent contact and proximity of grazing grounds to the natural water sources used to produce drinking water in the study area warrant further investigation of the public health relevance of these infections.

Acknowledgments

The authors would like to thank the farmers and research staff who participated in this study, with special thanks to Dr. Alexandros Stefanakis. The study was conducted within the framework of the COST Action FA0805 CAPARA. “Goat-parasite interactions: from knowledge to control”.


Novel Approaches to the Control of Parasites in Goats and Sheep.

Invited editors: Hervé Hoste, Smaragda Sotiraki, and Michel Alvinerie

References

  1. Aloisio F, Filippini G, Antenucci P, Lepri E, Pezzotti G, Caccio S-M, Pozio E. 2006. Severe weight loss in lambs infected with Giardia duodenalis assemblage B. Veterinary Parasitology, 142, 154–158. [CrossRef] [PubMed] [Google Scholar]
  2. Berrilli F, D’Alfonso R, Giangaspero A, Marangi M, Brandonisio O, Kaboré Y, Glé C, Cianfanelli C, Lauro R, Di Cave D. 2012. Giardia duodenalis genotypes and Cryptosporidium species in humans and domestic animals in Côte d’Ivoire: occurrence and evidence for environmental contamination. Transactions of the Royal Society of Tropical Medicine and Hygiene, 106, 191–195. [CrossRef] [PubMed] [Google Scholar]
  3. Cacciò SM, Sannella AR, Mariano V, Valentini S, Berti F, Tosini F, Pozio E. 2013. A rare Cryptosporidium parvum genotype associated with infection of lambs and zoonotic transmission in Italy. Veterinary Parasitology, 191, 128–131. [CrossRef] [PubMed] [Google Scholar]
  4. Castro-Hermida JA, García-Presedo I, Almeida A, González-Warleta M, Correia Da Costa JM, Mezo M. 2011. Cryptosporidium spp. and Giardia duodenalis in two areas of Galicia (NW Spain). Science of the Total Environment, 409, 2451–2459. [CrossRef] [Google Scholar]
  5. De Rancourt M, Fois N, Lavin MP, Tchakerian E, Vallerand F. 2006. Mediterranean sheep and goat production: an uncertain future. Small Ruminant Research, 62, 167–179. [CrossRef] [Google Scholar]
  6. Díaz P, Quílez J, Robinson G, Chalmers RM, Díez-Baños P, Morrondo P. 2010. Identification of Cryptosporidium xiaoi in diarrhoeic goat kids (Capra hircus) in Spain. Veterinary Parasitology, 172, 132–134. [CrossRef] [PubMed] [Google Scholar]
  7. Drumo R, Widmer G, Morrison LJ, Tait A, Grelloni V, D’Avino N, Pozio E, Cacciò SM. 2012. Evidence of host-associated populations of Cryptosporidium parvum in Italy. Applied Environmental Microbiology, 78, 3523–3529. [CrossRef] [Google Scholar]
  8. Ey PL, Mansouri M, Kulda J, Nohynkova E, Monis PT, Andrews RH, Mayrhofer G. 1997. Genetic analysis of Giardia from hoofed farm animals reveals artiodactyls-specific and potentially zoonotic genotypes. Journal of Eukaryotic Microbiology, 44, 625–635. [Google Scholar]
  9. Fayer R, Santin M. 2009. Cryptosporidium xiaoi n. sp. (Apicomplexa: Cryptosporidiidae) in sheep (Ovis aries). Veterinary Parasitology, 164, 192–200. [CrossRef] [PubMed] [Google Scholar]
  10. Fiuza VR, Cosendey RI, Frazão-Teixeira E, Santín M, Fayer R, de Oliveira FC. 2011. Molecular characterization of Cryptosporidium in Brazilian sheep. Veterinary Parasitology, 175, 360–362. [CrossRef] [PubMed] [Google Scholar]
  11. Geurden T, Geldhof P, Levecke B, Martens C, Berkvens D, Casaert S, Vercruysse J, Claerebout E. 2008. Mixed Giardia duodenalis assemblage A and E infections in calves. International Journal for Parasitology, 38, 259–264. [CrossRef] [PubMed] [Google Scholar]
  12. Geurden T, Thomas P, Casaert S, Vercruysse J, Claerebout E. 2008. Prevalence and molecular characterization of Cryptosporidium and Giardia in lambs and goat kids in Belgium. Veterinary Parasitology, 155, 142–145. [CrossRef] [PubMed] [Google Scholar]
  13. Geurden T, Vercruysse J, Claerebout E. 2010. Is Giardia a significant pathogen in production animals? Experimental Parasitology, 124, 98–106. [CrossRef] [PubMed] [Google Scholar]
  14. Giadinis ND, Panousis NK, Papadopoulos E, Antoniadou-Sotiriadou K, Karatzias H. 2006. The effects of halofuginone in cases of cryptosporidiosis in newborn lambs and kids in Greece. Proceedings of the 10th Greek Veterinary Congress, Athens. p. 195–196. [Google Scholar]
  15. Giadinis N, Papadopoulos E, Panousis N, Papazahariadou M, Lafi SQ, Karatzias H. 2007. Effect of halofuginone lactate on treatment and prevention of lamb cryptosporidiosis: an extensive field trial. Journal of Veterinary Pharmacology and Therapeutics, 30, 578–582. [CrossRef] [PubMed] [Google Scholar]
  16. Giangaspero A, Paoletti B, Iorio R, Traversa D. 2005. Prevalence and molecular characterization of Giardia duodenalis from sheep in central Italy. Parasitology Research, 96, 32–37. [CrossRef] [PubMed] [Google Scholar]
  17. Giles M, Chalmers R, Pritchard G, Elwin K, Mueller-Doblies D, Clifton-Hadley F. 2009. Cryptosporidium hominis in a goat and a sheep in the UK. Veterinary Record, 164, 24–25. [CrossRef] [Google Scholar]
  18. Gómez-Muñoz MT, Navarro C, Garijo-Toledo MM, Dea-Ayuela MA, Fernández-Barredo S, Pérez-Gracia MT, Domínguez-Márquez MV, Borrás R. 2009. Occurrence and genotypes of Giardia isolated from lambs in Spain. Parasitology International, 58, 297–299. [CrossRef] [PubMed] [Google Scholar]
  19. Gómez-Muñoz MT, Cámara-Badenes C, Martínez-Herrero Mdel C, Dea-Ayuela MA, Pérez-Gracia MT, Fernández-Barredo S, Santín M, Fayer R. 2012. Multilocus genotyping of Giardia duodenalis in lambs from Spain reveals a high heterogeneity. Research in Veterinary Science, 93, 836–842. [CrossRef] [PubMed] [Google Scholar]
  20. Hadjigeorgiou I, Vallerand F, Tsimpoukas K, Zervas G. 2002. The socio-economics of sheep and goat farming in Greece and the implications for the future rural development. Options Méditerranéennes Series B, 39, 83–93. [Google Scholar]
  21. Himonas CA, Antoniadou-Sotiriadou KS, Sotiraki ST, Papazahariadou MG. 1998. Intestinal protozoa of animals in Macedonia. Bulletin of the Hellenic Veterinary Medical Society, 49, 300–306. [Google Scholar]
  22. Imre K, Luca C, Costache M, Sala C, Morar A, Morariu S, Ilie MS, Imre M, Dărăbuş G. 2013. Zoonotic Cryptosporidium parvum in Romanian newborn lambs (Ovis aries). Veterinary Parasitology, 191, 119–122. [CrossRef] [PubMed] [Google Scholar]
  23. Karanis P, Ey PL. 1998. Characterization of axenic isolates of Giardia intestinalis established from humans and animals in Germany. Parasitology Research, 84, 442–449. [CrossRef] [PubMed] [Google Scholar]
  24. Lalle M, Jimenez-Cardosa E, Cacciò SM, Pozio E. 2005. Genotyping of Giardia duodenalis from humans and dogs from Mexico using a beta-giardin nested polymerase chain reaction assay. Journal of Parasitology, 91, 203–205. [CrossRef] [Google Scholar]
  25. Lasek-Nesselquist E, Welch DM, Sogin ML. 2010. The identification of a new Giardia duodenalis assemblage in marine vertebrates and a preliminary analysis of G. duodenalis population biology in marine systems. International Journal for Parasitology, 40, 1063–1074. [CrossRef] [PubMed] [Google Scholar]
  26. Lim YA, Mahdy MA, Tan TK, Goh XT, Jex AR, Nolan MJ, Sharma RS, Gasser RB. 2013. First molecular characterization of Giardia duodenalis from goats in Malaysia. Molecular and Cellular Probes, 27, 28–31. [CrossRef] [PubMed] [Google Scholar]
  27. McLauchlin J, Amar C, Pedraza-Diaz S, Nichols GL. 2000. Molecular epidemiological analysis of Cryptosporidium spp. in the United Kingdom: Results of genotyping Cryptosporidium spp. in 1,705 faecal samples from humans and 105 faecal samples from livestock animals. Journal of Clinical Microbiology, 38, 3984–3990. [PubMed] [Google Scholar]
  28. Morgan UM, Monis PT, Xiao L, Limor J, Sulaiman I, Raidal S, O’Donoghue P, Gasser R, Murray A, Fayer R, Blagburn BL, Lal AA, Thompson RC. 2001. Molecular and phylogenetic characterisation of Cryptosporidium from birds. International Journal for Parasitology, 31, 289–296. [CrossRef] [PubMed] [Google Scholar]
  29. Mueller-Doblies D, Giles M, Elwin K, Smith RP, Clifton-Hadley FC, Chalmers RM. 2008. Distribution of Cryptosporidium species in sheep in the UK. Veterinary Parasitology, 154, 214–219. [CrossRef] [PubMed] [Google Scholar]
  30. Nolan MJ, Jex AR, Pangasa A, Young ND, Campbell AJ, Stevens M, Gasser RB. 2010. Analysis of nucleotide variation within the triose-phosphate isomerase gene of Giardia duodenalis from sheep and its zoonotic implications. Electrophoresis, 31, 287–298. [CrossRef] [PubMed] [Google Scholar]
  31. Olson ME, McAllister TA, Deselliers L, Morck DW, Cheng KJ, Buret AG, Ceri H. 1995. Effects of giardiasis on production in a domestic ruminant (lamb) model. American Journal of Veterinary Research, 56, 1470–1474. [PubMed] [Google Scholar]
  32. Panousis N, Diakou A, Giadinis N, Papadopoulos E, Karatzias H, Haralampidis S. 2008. Prevalence of Cryptosporidium infection in sheep flocks with a history of lambs’ diarrhoea. Revue de Médecine Vétérinaire, 159, 528–531. [Google Scholar]
  33. Paraud C, Pors I, Chartier C. 2010. Evaluation of oral tilmicosin efficacy against severe cryptosporidiosis in neonatal kids under field conditions. Veterinary Parasitology, 170, 149–152. [CrossRef] [PubMed] [Google Scholar]
  34. Peng MM, Matos O, Gatei W, Das P, Stantic-Pavlinic M, Bern C, Sulaiman IM, Glaberman S, Lal AA, Xiao L. 2001. A comparison of Cryptosporidium subgenotypes from several geographic regions. Journal of Eukaryotic Microbiology Supplement, 48, 28S–31S. [CrossRef] [Google Scholar]
  35. Quilez J, Torres E, Chalmers RM, Hadfield SJ, Cacho E, Sanchez-Acedo C. 2008. Cryptosporidium Genotypes and subtypes in lambs and goat kids in Spain. Applied and Environmental Microbiology, 74, 6026–6031. [CrossRef] [PubMed] [Google Scholar]
  36. Rieux A, Paraud C, Pors I, Chartier C. 2013. Molecular characterization of Cryptosporidium spp. in pre-weaned kids in a dairy goat farm in western France. Veterinary Parasitology, 192, 268–272. [CrossRef] [PubMed] [Google Scholar]
  37. Robertson LJ. 2009. Giardia and Cryptosporidium infections in sheep and goats: a review of the potential for transmission to humans via environmental contamination. Epidemiology and Infection, 137, 913–921. [CrossRef] [PubMed] [Google Scholar]
  38. Robertson LJ, Gjerde BK, Hansen EF. 2010. The zoonotic potential of Giardia and Cryptosporidium in Norwegian sheep: a longitudinal investigation of 6 flocks of lambs. Veterinary Parasitology, 171, 140–145. [CrossRef] [PubMed] [Google Scholar]
  39. Ruiz A, Foronda P, Gonzalez JF, Guedes A, Abreu-Acosta N, Molina JM, Valladares B. 2008. Occurrence and genotype characterization of Giardia duodenalis in goat kids from the Canary Islands, Spain. Veterinary Parasitology, 154, 137–141. [CrossRef] [PubMed] [Google Scholar]
  40. Ryan UM, Bath C, Rovertson I, Read C, Elliot A, Mcinnes L, Traub R, Besier B. 2005. Sheep may not be an important zoonotic reservoir for Cryptosporidium and Giardia Parasites. Applied Environmental Microbiology, 71, 4992–4997. [CrossRef] [Google Scholar]
  41. Santin M, Trout JM, Fayer R. 2007. Prevalence and molecular characterization of Cryptosporidium and Giardia species and genotypes in sheep in Maryland. Veterinary Parasitology, 146, 17–24. [CrossRef] [PubMed] [Google Scholar]
  42. Silverlås C, Mattsson JG, Insulander M, Lebbad M. 2012. Zoonotic transmission of Cryptosporidium meleagridis on an organic Swedish farm. International Journal for Parasitology, 42, 963–967. [CrossRef] [PubMed] [Google Scholar]
  43. Stefanakis A, Volanis M, Zoiopoulos P, Hadjigeorgiou I. 2007. Assessing the potential benefits of technical intervention in evolving the semi-intensive dairy-sheep farms in Crete. Small Ruminant Research, 72, 66–72. [CrossRef] [Google Scholar]
  44. Sweeny JP, Robertson ID, Ryan UM, Jacobson C, Woodgate RG. 2011. Impacts of naturally acquired protozoa and strongylid nematode infections on growth and faecal attributes in lambs. Veterinary Parasitology, 184, 298–308. [CrossRef] [PubMed] [Google Scholar]
  45. Wang Y, Feng Y, Cui B, Jian F, Ning C, Wang R, Zhang L, Xiao L. 2010. Cervine genotype is the major Cryptosporidium genotype in sheep in China. Parasitology Research, 106, 341–347. [CrossRef] [PubMed] [Google Scholar]
  46. Yang R, Jacobson C, Gordon C, Ryan U. 2009. Prevalence and molecular characterisation of Cryptosporidium and Giardia species in pre-weaned sheep in Australia. Veterinary Parasitology, 161, 19–24. [CrossRef] [PubMed] [Google Scholar]
  47. Zhang W, Zhang X, Wang R, Liu A, Shen Y, Ling H, Cao J, Yang F, Zhang X, Zhang L. 2012. Genetic characterizations of Giardia duodenalis in sheep and goats in Heilongjiang Province, China and possibility of zoonotic transmission. PLoS Neglected Tropical Diseases, 6, e1826. [CrossRef] [PubMed] [Google Scholar]

Cite this article as: Tzanidakis N, Sotiraki S, Claerebout E, Ehsan A, Voutzourakis N, Kostopoulou D, Stijn C, Vercruysse J & Geurden T: Occurrence and molecular characterization of Giardia duodenalis and Cryptosporidium spp. in sheep and goats reared under dairy husbandry systems in Greece. Parasite, 2014, 21, 45.

All Tables

Table 1.

Overview of the 21 farms included in the study, with the number of sheep and/or goats on the farms (N) and the type of management system (Sampled = number of animals sampled on each farm).

Table 2.

Results for molecular identification of Giardia duodenalis positive samples in goat kids and lambs, based on the B-giardin (= beta-giardin) or triose phosphate isomerase (TPI) gene (NA = no amplification; A = assemblage A; E = assemblage E; A + E = mixed infection with assemblage A and E).

Table 3.

Results for molecular identification of Cryptosporidium positive samples in goat kids and lambs.

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.