The hidden burden of giardiasis: Characterizing alterations in hematological, hepatic, and iron profile

Abstract

Giardiasis is increasingly recognized as a systemic illness beyond its classical intestinal manifestations. This study aimed to characterize systemic manifestations across age groups by evaluating hematological, hepatic, and iron profiles. A retrospective cross-sectional analysis was conducted on 105 giardiasis cases in a tertiary center between 2022 and 2024, stratified by age. All infants exhibited reduction in packed cell volume, mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH); adolescents showed significant MCV reduction (P = 0.018); young adults displayed reduced MCH (P = 0.019). Elevated bilirubin is observed in children (P = 0.025) and adolescents (P = 0.009). Most striking was iron metabolism dysregulation in 100% adults aged 18–60 years. The study also showed a male predominance (70.5%), with a seasonal peak during the monsoon period. These findings indicate that giardiasis causes age-specific systemic effects, with iron metabolism disruption in adults emerging as a key treatment focus.

INTRODUCTION

Giardiasis, a World Health Organization (WHO)-listed neglected disease, poses a significant global health burden, especially in low-resource settings, with prevalence reaching up to 30% in the low-income countries.[1] Poor hygiene, inadequate sanitation, and unsafe water are the key risk factors driving the high prevalence of intestinal parasites in developing countries.[2] According to the WHO intestinal parasitic infections account for 39 million disability-adjusted life years globally, affecting 21% of Indians, with Giardia intestinalis being the most common (40%), followed by Ancylostoma duodenale, Ascaris lumbricoides, Strongyloides stercoralis, Entamoeba histolytica, and Trichuris trichiura.[3,4,5] In India, Giardia intestinalis prevalence ranges from 0.4% to 70%, with up to 50% asymptomatic cyst carriers in rural regions.[6] Giardiasis, most common in children under 5 years but also affecting adolescents and adults, typically presents with diarrhea, weight loss, abdominal cramps, and malabsorption and may be associated with iron-deficiency anemia, micronutrient deficiencies, growth retardation, and liver dysfunction.[7,8,9,10] Due to limited data on anemia and hepatic profiling in giardiasis in India, this study was conducted to assess hematological, liver function, and iron profile abnormalities across various age groups at a tertiary care setting.

MATERIALS AND METHODS

This hospital-based, retrospective, and cross-sectional study, conducted at All India Institute of Medical Sciences Patna from January 2022 to June 2024, included all patients, whose stool microscopy test for intestinal parasites was requested and yielded Giardia intestinalis cyst and/or trophozoites. Demographic details, laboratory parameters, hospital admission, and seasonal data for all patients were collected from the medical records and the hospital information system.

The patients were divided into two major groups – <18 years and ≥18 years and subsequently into eight minor sub-groups, i.e. (0–2 years, 2–12 years, and 13 to <18 years) and (18–30 years, 31–40 years, 41–50 years, 51–60 years, and >60 years), respectively. Among laboratory parameters, complete blood count, liver function test, and iron profile (if tested) were taken into consideration. All study parameters were analyzed across age subgroups and classified as “altered” based on age-specific normal reference ranges, with the laboratory parameters and their corresponding reference values listed below:[11]

• Hemoglobin <11 g/dl for all ages

• Total red blood cells (RBC) count <3.5 million/μL for all ages

• Mean corpuscular volume (MCV) <96 fL for age 1 and 2 years, <80 fL for >2 years

• Mean corpuscular hemoglobin (MCH) <32 pg for age 1 and 2 years, <27 pg for >2 years

• Packed cell volume (PCV) <40% for all ages

• Total white blood cells (WBC) count >30,000/μL for age 1, >17,000/μL for age 2, >10,000/μL for >2 years

• Absolute eosinophil count (AEC) >500 cells/μL

• Total bilirubin >1.2 mg/dl for 1 and 2 years, >1 mg/dl for >2 years

• Indirect bilirubin >1 mg/dl for 1 and 2 years, >0.8 mg/dl for >2 years

• Alkaline phosphatase (ALP) >235 for 1 year, >300 for 2–15 years, >120 units/L for >15 years

• Alanine transaminase (ALT) >70 for age 1 and 2 years, >36 units/L for >2 years

• Total serum iron <120 μg/dl for 1 and 2 years, <70 μg/dl for >2 years

• Total iron-binding capacity (TIBC) 250–460 μg/dl for all ages

Statistical analyses

All data were entered in Microsoft Excel 2019 and analyzed using licensed SPSS version 22.0 (IBM, Armonk, NY, USA). Normality of continuous variables was assessed using Q-Q plots and the Shapiro–Wilk test; data were expressed as mean (± standard deviation) for normal distributions and median (interquartile range [IQR]) for skewed data. Categorical variables were reported as proportions. For each age subgroup within the <18 and ≥ 18 years categories, laboratory parameter alterations were compared to others in the same major group using Chi-square or Fisher’s exact test. P < 0.05 was considered statistically significant, indicating whether the proportion of altered laboratory values in a specific age subgroup significantly differs from those in the remaining participants of the same major age category.

RESULTS

Giardia intestinalis cysts and/or trophozoites were detected in 105 of 6281 stool samples examined during the study period, with cases nearly equally distributed between patients aged <18 years (n = 52; 49.5%) and ≥18 years (n = 53; 50.5%). Table 1 summarizes the patient demographics, hospital admission, seasonal variation, and laboratory characteristics of all these patients. Gender-wise distribution showed males constituted a significantly higher proportion of infections.

Table 1.

Patient demographics and laboratory characteristics

Demographic and laboratory parameters								Observed values, median (IQR), or mean±1 SD
Demographics (n=105)
Age (years)								18 (5–34)
Gender, n (%)
Male								74 (70.5)
Female								31 (29.5)
<18 years								>18 years
<1 year (5)		2–12 year (38)		13–17 year (9)		18–30 year (20)		31–40 year (14)		41–50 year (11)		51–60 year (4)		>60 year (4)
Male	Female	Male	Female	Male	Female	Male	Female	Male	Female	Male	Female	Male	Female	Male	Female
3	2	25	13	7	2	17	3	10	4	8	3	3	1	1	3
Hospitalization status, n (%)
OPD								82 (78.1)
IPD								23 (21.9)
Seasonal variation, n (%)
January–March								10 (9.5)
April–June								46 (43.85)
July–September								33 (31.42)
October–December								16 (15.23)
Hb profile (n=99)
Hb (g/dL)								11.90±2.36
Total RBCs count (million cells/μL)								4.59 (4.01–5.11)
Total WBCs count (cells/μL)								9.11 (6.70–11.50)
PCV (%)								37.2 (34.0–41.7)
MCV (fL)								84.3 (79.0–89.5)
MCH (pg)								27.4 (24.9–29.3)
Absolute eosinophil count (cells/μL)								262 (139–583)
Liver function test profile (n=85)
Total bilirubin (mg/dL)								0.55 (0.36–0.81)
Indirect bilirubin (mg/dL)								0.39 (0.27–0.64)
ALP (IU/L)								123.0 (89.3–197.0)
ALT (IU/L)								24.9 (18.4–34.6)
Iron profile (n=12) (μg/dL)
Total serum iron								51.0±33.1
TIBC								278±156

Hb: Hemoglobin, RBCs: Red blood cells, WBCs: White blood cells, PCV: Packed cell volume, MCV: Mean corpuscular volume, MCH: Mean corpuscular hemoglobin, ALP: Alkaline phosphatase, ALT: Alanine aminotransferases, TIBC: Total iron-binding capacity, SD: Standard deviation, IQR: Interquartile range, OPD: Outpatient department, IPD: Inpatient department

The hematological profile of patients with giardiasis showed a mean hemoglobin of 11.90 ± 2.36 g/dL, with median RBC and WBC counts of 4.59 million cells/μL (IQR: 4.01–5.11) and 9.11 × 10³ cells/μL (IQR: 6.70–11.50), respectively. PCV had a median value of 37.2% (IQR: 34.0–41.7), MCV was 84.3 fL (IQR: 79.0–89.5), and MCH 27.4 pg (IQR: 24.9–29.3). The median AEC was 262 cells/μL (IQR: 139–583). Among liver function tests, median total and indirect bilirubin were 0.55 mg/dL (IQR: 0.36–0.81) and 0.39 mg/dL (IQR: 0.27–0.64), respectively. ALP and ALT showed median values of 123.0 IU/L (IQR: 89.3–197.0) and 24.9 IU/L (IQR: 18.4–34.6), respectively. The iron profile revealed reduced mean serum iron (51.0 ± 33.1 μg/dL) and TIBC (278 ± 156 μg/dL).

Alteration in various laboratory parameters among patients <18 years old with Giardia intestinalis is depicted in Table 2. The hematological parameters revealed distinct variations that differed across various age groups, highlighting the influence of age on these physiological measures. Infants (<1 year) demonstrated marked reduction in PCV (100%), MCV (100%), and MCH (100%). MCV levels were significantly lower among 13–17 years group (P = 0.018). A significantly elevated levels of total bilirubin were seen among 2–12 years (P = 0.025) and 13–17 years group (P = 0.009) with elevation in the ALP levels among less than 1 year group (P = 0.05).

Table 2.

Alterations in various laboratory parameters for giardia intestinalis infection among <18 year and >18 year patients

Major group Minor subgroups			<18 years (n=52; 49.5%; males=35)
			<1 year (n=5) 1*, n (%)		P	2–12 years (n=38)*, n (%)	P	13–17 years (n=9)*, n (%)		P
Haematological profile alterations
Hb			3/4 (75)	0.079	11/37 (29.73)	0.814	1/8 (12.5)		0.406
RBC			0/4 (0)	1.00	3/37 (8.12)	1.00	1/8 (12.5)		0.522
WBC			0/4 (0)	0.282	14/37 (37.84)	1.00	4/8 (50)		0.442
PCV			4/4 (100)	0.568	30/37 (81.08)	0.689	5/8 (62.5)		0.333
MCV			4/4 (100)	0.112	21/37 (56.76)	0.362	1/8 (12.5)		0.018
MCH			4/4 (100)	0.288	26/37 (70.27)	0.443	3/8 (37.5)		0.093
Absolute eosinophil count (>500 cells/μL)			1/4 (25)	1.00	13/37 (36.11)	0.909	3/8 (42.85)		1.00
Liver function test profile alterations
Total bilirubin			0/2	1.00	2/30 (6.67)	0.025	4/8 (50)		0.009
Indirect bilirubin			0/2	1.00	1/30 (3.34)	0.148	2/8 (25)		0.096
ALP			1/2	0.05	0/30 (0)	0.251	0/8 (0)		1.00
ALT			0/2	1.00	3/10 (10)	0.559	0/8 (0)		1.00
Iron profile alterations
Total iron			NA	NA	1/2	1.00	NA		NA
TIBC			NA	NA	1/2	1.00	NA		NA
Major group Minor groups	≥18 years (n=53; 50.5%; males=39)
	18–30 years (n=20)*, n (%)	P	31–40 years (n=14)*, n (%)	P	41–50 years (n=11)*, n (%)	P	51–60 years (n=4)*, n (%)	P	>60 years (n=4)*, n (%)	P
Haematological profile alterations
Hb	3/19 (15.79)	0.056	3/13 (23.08)	0.734	4/11 (36.36)	0.475	3/4 (75)	0.061	2/4 (50)	0.310
RBC	2/18 (11.12)	0.650	0/13 (0)	0.174	2/11 (18.18)	0.605	2/4 (50)	0.068	1/4 (25)	0.417
WBC	5/18 (27.78)	0.924	4/13 (30.77)	0.837	2/11 (18.18)	0.474	2/4 (50)	0.567	1/4 (25)	1.00
PCV	7/18 (38.89)	0.233	5/13 938.46)	0.474	6/11 (54.54)	0.565	3/4 (75)	0.329	3/4 (75)	0.329
MCV	0/18 (0)	0.148	2/13 (15.38)	0.598	1/11 (9.09)	1.00	0/4 (0)	1.00	2/4 (50)	0.046
MCH	1/18 (5.56)	0.019	3/13 (23.08)	1.00	3/11 (27.27)	1.00	3/4 (75)	0.052	3/4 (75)	0.052
Absolute eosinophil count (>500 cells/μL)	6/18 (33.34)	0.059	4/13 (33.33)	0.279	0/11 (0)	0.090	0/4 (0)	0.568	0/4 (0)	0.568
Liver function test profile alterations
Total bilirubin	4/15 (26.67)	0.708	3/11 (27.27)	1.00	1/11 (9.09)	0.240	1/4 (25)	1.00	2/4 (50)	0.256
Indirect bilirubin	5/15 (33.34)	0.086	1/11 (9.09)	0.410	0/11 (0)	0.084	1/4 (25)	1.00	2/4 (50)	0.180
ALP	3/15 (20)	1.00	2/11 (18.18)	1.00	3/11 (27.27)	0.668	1/4 (25)	1.00	0/4 (0)	0.566
ALT	6/15 (40)	0.792	6/12 (50)	0.409	6/11 (54.54)	0.257	0/4 (0)	0.138	0/4 (0)	0.138
Iron profile alterations
Total iron	1/1	1.00	1/1	1.00	3/3	1.00	2/2	1.00	2/3	0.333
TIBC	0/1	1.00	0/1	1.00	1/3	1.00	1/2	1.00	1/3	1.00

∗Laboratory parameter analysis was conducted on available data; patients with missing values were excluded from statistical calculations. RBCs: Red blood cell count, WBCs: White blood cells, PCV: Packed cell volume, MCV: Mean corpuscular volume, MCH: Mean corpuscular hemoglobin, ALP: Alkaline phosphatase, ALT: Alanine aminotransferases, TIBC: Total iron-binding capacity, Hb: Hemoglobin, NA: Not available

Similarly, alteration in various laboratory parameters for Giardia intestinalis infection among ≥18 years patients is depicted in Table 2. MCV level was significantly lower among more than 60 years group (P = 0.046) while MCH level was significantly reduced among 18–30 years group (P = 0.019). Iron metabolism studies revealed a striking pattern, with total iron abnormalities observed in 100% of adults aged 18–60 years, while TIBC showed variable alterations (0%–50%).

DISCUSSION

The present study reveals distinct age-related clinical and laboratory patterns in giardiasis, reporting a lower prevalence (1.67%) than previously documented rates in India (5.25%–22%).[7,12]

Our study showed a male predominance consistent with earlier reports, although the cause remains uncertain.[7] Giardiasis occurred year-round, with peak cases during premonsoon and monsoon seasons, aligning with patterns observed in the tropical regions where rainfall affects transmission.[7]

Our study revealed significant age-wise hematological variations, with all infants showing alterations in PCV, MCV, and MCH, likely attributable to their developing immune system and enhanced intestinal permeability. Significant reduction in MCV was documented in adolescents (P = 0.018) considering menstrual blood loss in adolescent females might act as a confounding factor contributing to the observed lower MCV in the 13–17 years’ age group, while distinct patterns of MCV and MCH reduction were observed in the elderly (P = 0.046) and young adult populations (P = 0.019), respectively. The gender wise distribution of various subgroups is depicted in Table 1. These findings corroborate previous studies highlighting the substantial impact of G. intestinalis on iron homeostasis, primarily through its colonization of the duodenum – the principal site of iron absorption – leading to malabsorption syndrome and subsequent iron-deficiency anemia.[8,13,14]

The presence of absolute eosinophilia (>500 cells/µl) in younger but the absence in older age groups suggests age-related immune differences in response to giardiasis, warranting further study.

The study revealed significant age-specific hepatobiliary involvement in giardiasis, with elevated total bilirubin in children (P = 0.025) and adolescents (P = 0.009) and elevated ALP in infants (P = 0.05), supporting previous findings of hepatic dysfunction in chronic G. intestinalis infection. The age-specific liver enzyme alterations observed offer new insights into the varied extra-intestinal, particularly hepatobiliary, manifestations of giardiasis.[15] While an isolated ALP elevation was noted in few infants, the absence of complementary liver function parameters (e.g. ALT, AST, and GGT) limits definitive attribution to hepatobiliary involvement. Given physiologically, high ALP in growing infants and small sample size, findings should be interpreted cautiously. Larger studies are needed to clarify its clinical relevance.

The observed pattern of iron metabolism abnormalities, especially in adults (18–60 years), highlights potential giardia-induced malabsorption affecting duodenal absorption. While previous studies report significant iron deficiency linked to giardiasis, our study did not find this association to be statistically significant.[14]

The predominance of outpatient cases in our study (78.1%) suggests that most infections present with mild-to-moderate severity, consistent with global epidemiological patterns, while hospitalizations (21.9%), mainly in <10 and >55 years, indicating potential for severe infection in vulnerable populations.

CONCLUSION

Giardia intestinalis presents a significant public health challenge, especially in children from resource-limited settings, due to its association with growth retardation, nutritional deficiencies, and chronic sequelae, underscoring the need for better diagnostics and systematic laboratory evaluation to enable effective management and mitigate long-term health and socioeconomic consequences.

Limitation

Our findings revealed significant metabolic alterations in giardiasis patients, highlighting potential pathogenic mechanisms and an association with various laboratory parameters that warrant further investigation with appropriate controls to establish causality.

Ethical clearance

As this was a retrospective study, ethical approval was waived off by the Institutional Ethics Committee.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.