Current situation of Giardia infection in Spain: Implications for public health

Table 1 Giardia species and assemblages (adapted from[4,5])

Species	Main hosts	Reported in human infections	Reported in surface waters
G. duodenalis	Mammals	Yes	Yes
G. agilis	Amphibians	No	No
G. ardeae	Birds	No	No
G. microti	Rodents	No	No
G. muris	Rodents	No	No
G. psittaci	Birds	No	No
Assemblages
A (= G. duodenalis)	Mammals	Yes	Yes
B (= G. enterica1)	Mammals	Yes	Yes
C/D (= G. canis1)	Canines	Yes2	No
E (= G. bovis1)	Domestic ruminants, pigs	Yes2	No
F (= G. cati1)	Cats	Yes2	No
G (= G. simondi1)	Mice, rats	No	No
H	Seals	No	No

¹Species names recently proposed;

²To be confirmed with further molecular characterization.

Table 2 Giardia outbreaks notified to the Spanish epidemiological surveillance network between 2003 and 2010

Year	Confirmed cases	Hospitalized cases	Location	Transmission
2003	6	0	School	Direct person-to-person
	38	0	School	Direct person-to-person
	3	0	School	Direct person-to-person
	26	0	School	Direct person-to-person
2004	30	0	Public premises	Drinking water
	4	0	School	Direct person-to-person
	14	1	Public premises	Direct person-to-person
2005	8	0	School	Drinking water
20061	–	–	–	–
2007	17	0	School	Unknown
	6	0	Public premises	Unknown
	3	0	School	Direct person
2008	5	0	Private premises	Unknown
	4	0	School	Unknown
	3	0	School	Direct person-to-person
	32	0	Swimming pool	Water
20091	–	–	–	–
20101	–	–	–	–

¹No outbreaks were reported in 2006, 2009 and 2010.

Table 3 Detection of Giardia spp. in human stool samples in Spain (1990 onwards)

Population	Province/region	Period	No. samples	Technique(s)	Infection rate (%)	Ref.
Mixed1	Madrid	NS	405	CM	7.4	[20]
Urban paediatric12	Salamanca	1987-1989	354	CC + CM	13.0	[21]
Rural paediatric1	Ávila	1992-1993	318	CC + CM	4.4	[87]
Innate12	Madrid	1991-1993	1281	CC + CM	21.0	[22]
Urban paediatric1	Cuenca	NS	891	CC + CM	36.4	[88]
Day care centre12	Salamanca	1990-1991	523	CC + CM + IFA	25.3	[23]
Urban and rural paediatric1	Andalusia	1994-1996	1917	CC + CM	5.0	[89]
Immigrants12	Madrid	1989-1999	NS	CC + CM	5.4	[25]
Urban paediatric1	Valencia	2005	270	CC + CM	4.3	[90]
Immigrants12	Barcelona	2001-2004	2464	NS	5.4	[26]
Outpatients2	Catalonia	1999-2005	13 913	CM	3.9	[24]
Rural paediatric1	Álava	2008-2009	328	CpAg-ELISA + ICT	3.5	[29]

CC: Concentration techniques; CM: Conventional microscopy; CpAg-ELISA: Enzyme-linked immunosorbent assay for the detection of copro-antigens; ICT: Inmunochromatography assay; IFA: Immunofluorescence microscopy; NS: Not specified.

¹Asymptomatic;

²Symptomatic (defined as the presence of diarrhoea and/or vomiting).

Table 4 Detection of Giardia spp. faecal samples from farmed animals in Spain (1990 onwards)

Specie	Province/region	Period	No. samples	Technique(s)	Infection rate (%)	Ref.
Cattle12	Aragón	1990-1993	554	CC + CM	11.7	[30]
Cattle1	Granada	NS	592	CC + CM	0.2	[37]
Cattle1	Galicia	2005	734	IFA	30.1	[31]
Cattle1	Galicia	NS	379	IFA	26.6	[32]
Cattle12	Galicia	2007	1316	IFA	4.9-28.54	[34]
Cattle1	Galicia	2008-2009	649	CC + IFA	21-383	[33]
Cattle1	Álava	2008-2009	227	CpAg-ELISA + ICT	1.4	[29]
Sheep1	Granada	NS	1165	CC + CM	6.3	[37]
Sheep12	Zaragoza	1995-1997	583	CC + CM	2.7	[91]
Sheep1	Galicia	NS	575	IFA	32.7	[36]
Sheep1	Galicia	NS	446	IFA	19.2	[32]
Sheep1	Valencia	2005-2007	386	IFA + PCR	42.0	[35]
Sheep1	Galicia	2008-2009	377	CC + IFA	26-443	[33]
Goats1	Granada	NS	574	CC + CM	4.0	[37]
Goats1	Galicia	NS	116	IFA	19.8	[32]
Goats12	Canary Islands	2006-2007	315	IFA	42.2	[75]
Ostriches/rheas	Various	1997-2000	177	Nec. + CC + CM	< 1	[92]

CC: Concentration techniques; CM: Conventional microscopy; IFA: Immunofluorescence microscopy; CpAg-ELISA: Enzyme-linked immunosorbent assay for the detection of copro-antigens; ICT: Inmunochromatography assay; Nec.: Necropsy; NS: Not specified; PCR: Polymerase chain reaction.

¹Asymptomatic;

²Symptomatic (defined as the presence of diarrhoea);

³Depending on age and geographical location;

⁴Depending on age and sampling season.

Table 5 Detection of Giardia spp. in faecal samples from pets in Spain (1990 onwards)

Specie	Province/region	Period	No. samples	Technique(s)	Infection rate (%)	Ref.
Dogs12	Zaragoza	1992	81	CC + CM	4.9	[41]
Dogs12	Granada	NS	912	CC + CM	12.1	[37]
Dogs12	Murcia	2001-2004	48	Nec. + CC + CM	10.0	[42]
Dogs12	Córdoba	NS	1500	CC + CM + Nec.	1.0	[45]
Dogs12	Madrid	NS	1161	CC + CM	7.1	[44]
Dogs2	Various	2005-2006	441	SNAP Giardia test3	25.1	[43]
Dogs + cats	Madrid	NS	79	CC + CM	17.7	[46]
Cats2	Various	2005-2006	54	SNAP Giardia test3	14.6	[43]

CC: Concentration techniques; CM: Conventional microscopy; Nec.: Necropsy; NS: Not specified.

¹Asymptomatic;

²Symptomatic (defined as the presence of diarrhoea and/or vomiting);

³Idexx Laboratories, Westbrook, ME.

Table 6 Detection of Giardia spp. in faecal samples from wild and captive animals in Spain (1990 onwards)

Specie	Province/region	Period	No. samples	Technique(s)	Infection rate (%)	Ref.
Deers	Galicia	2008-2009	181	CC + IFA	6-142	[33]
Roe deers	Galicia	2008-2009	224	CC + IFA	5.3	[48]
Wild boars	Galicia	2008-2009	279	CC + IFA	3-5	[33]
Wild boars	Galicia	2008-2009	381	CC + IFA	1.3	[48]
Otters	Galicia	2004-2005	437	CC + IFA	6.8	[47]
Nonhuman primates1	Madrid and Valencia	NS	20	CC + CM + PCR	70.0	[49]

CC: Concentration techniques; CM: Conventional microscopy; IFA: Immunofluorescence microscopy; Nec.: Necropsy; NS: Not specified; PCR: Polymerase chain reaction.

¹Captive animals from zoological gardens;

²Depending on geographical location.

Table 7 Detection of Giardia spp. in surface waters in Spain (1990 onwards)

Type water	Province/region	Period	No. samples	Positive samples (%)	Concentration (cysts/L)	Ref.
Rivers	Álava	2000-2002	52	92.3	65	[59]
	Galicia	2004	7	85.7	1-20	[53]
	Galicia	2007	116	67.2	2-722	[34]
	Galicia	2009	28	60.7	1-160	[60]
Reservoirs	Álava	2000-2002	36	55.5	0.6	[59]
DWTP influent	Álava	2000-2002	57	26.9-45.2	0.05-0.5	[59]
	Galicia	2007	64	100.0	1-13	[61]
	Galicia	2008-2009	12	25-58	1.3-1.4	[33]
	Galicia	2009	52	42.3	1-7	[60]
DWTP effluent1	Álava	2000-2002	57	0-19.2	0-0.01	[59]
	Galicia	2007	64	100.0	0.5-4	[61]
	Galicia	2008-2009	12	25-33	1-1.3	[33]
	Galicia	2009	52	36.5	1-5	[60]
Tap water2	Álava	2000-2002	82	26.8	0.02	[59]
WTP influent	Galicia	2007	48	100.0	89-8305	[62]
	Galicia	2004	11	90.9	29-1433	[53]
	Galicia	2008-2009	12	100.0	415-2752	[33]
	Galicia	2009	50	98.0	2-14 400	[60]
WTP effluent1	Galicia	2007	48	100.0	79-2469	[62]
	Galicia	2004	16	87.5	233-1131	[54]
	Galicia	2008-2009	12	100.0	138-560	[33]
	Galicia	2009	50	96.0	2-6000	[60]

DWTP: Drinking water treatment plant; WTP: Wastewater treatment plant.

¹Water treatment facilities with different physical, biological and/or chemical treatment processes in place;

²Tap water with chlorination treatment only.

Table 8 Identification of Giardia isolates in Spain spp. from different origins

Origin	No. samples genotyped	Loci tested	Genotypes (assemblages, %)	Ref.
Human	108	tpi	AII (39.8); AII + B (3.7); B (56.5)	[63]
Human	211	tpi	AII + B (13.3); B (86.7)	[64]
Human	7	tpi	AII (28.6); AII + B (14.3); B (57.1)	[29]
Farm animals
Cattle	4	β-giardin + gdh	E (100.0)	[32]
Cattle	50	β-giardin	AI (36.0); E (64.0)	[33]
Sheep		β-giardin	E (100.0)	[36]
Sheep	12	β-giardin + gdh	B (8.3); E (91.7)	[32]
Sheep	75	β-giardin	AI (1.3); E (98.7)	[35]
Sheep	31	β-giardin	B (35.5); E (64.5)	[33]
Goats	1	β-giardin + gdh	E (100.0)	[32]
Goats	39	tpi + β-giardin	E (100.0)	[75]
Captive animals
Nonhuman primates	14	SSrRNA, gdh, tpi, β-giardin	A (64.3); B (35.7)	[49]
Food
Oysters	1	tpi	B (100%)	[52]
Water
Rivers	NS	β-giardin	AI (NS); AI + E (NS); AII (NS); AII + E (NS); E (NS)	[34]
DWTP influent	NS	β-giardin	AI + E (NS); AII (NS); AII + E (NS)	[61]
DWTP effluent	NS	β-giardin	AI + E (NS); AII (NS)	[61]
WTP influent	NS	β-giardin	AI (NS); AI + E (NS); AII (NS); AII + E (NS)	[62]
WTP influent	10	β-giardin	AII (50.0); AI + AII (10.0); AI + E (20.0); AII + E (20.0)	[33]
WTP effluent	NS	β-giardin	AI (NS); AI + E (NS); AII (NS); AII + E (NS)	[62]
WTP effluent	12	β-giardin	AI (8.3); AII (50.0); AI + E (16.7); AII + E (16.7); E (8.3)	[33]

DWTP: Drinking water treatment plant; NS: Not specified; WTP: Wastewater treatment plant.