The investigation of parasitic infections in patients with HD, followed by the desired treatment if ‎tested positive, can, therefore, play a significant role in the process of restoring better quality of life for ‎these patients [10]. This work aimed to study the prevalence of common parasitic infections and ‎associated symptoms and signs among pediatric patients undergoing HD at Ain Shams University ‎Pediatric Hemodialysis Unit (PDU).‎

PATIENTS AND METHODS

This cross-sectional study was conducted in the Pediatric Hemodialysis Unit, Children`s Hospital, Ain Shams University, Cairo, Egypt. The study period was from January 2018 to March 2019.

Study groups:

Patients` group: 50 patients on hemodialysis.

Control group: 20 children with no renal disease.

Out of our 50 cases, we found 17 patients who had CAKUT as a primary etiology of CKD e.g. renal dysplasia, posterior urethral valve, and vesicoureteral reflux, 12 patients had a history of chronic glomerulonephritis e.g. IgA nephropathy, chronic Henoch Schonlein purpura, and lupus nephritis, 4 patients with a history of congenital nephrotic syndrome, 5 patients with a history of HUS, 4 patients who had SRNS, 2 cases of Joubert syndrome, 3 cases of primary hyperoxaluria and 3 cases of drug-induced chronic interstitial nephritis.

The mean age of cases was 14.35 ± 4.44 years after the exclusion of those who were receiving antiparasitic medications at the time of the study, those who were receiving immunosuppressive drugs at the time of the study or 4 weeks before the onset of the study, and children who were having additional disease-causing an immunocompromised state e.g., DM, malignancy and 1ry immunodeficiency.

A detailed history was taken that included age, sex, residence, resources of drinking water, a history of recent travel to foreign countries, and recent exposure to animals during the last three months. Moreover, some clinical data including symptoms e.g., diarrhea, nausea, vomiting, fever, mucous or blood in the stool, abdominal pain, bloating, flatulence, general fatigue, tender lymph nodes, and loss of weight. A complete physical examination was recorded including enlarged lymph nodes and abdominal examination.

Three fecal samples were collected from each study participant. Stool analysis for parasites was done using direct wet smear (saline and Lugol’s iodine) of the fresh samples [11][12]and concentrated ones using formol ether concentration techniques to detect protozoa and ova of helminths [13]. Also, staining of stool samples using the modified Ziehl-Neelsen stain was performed to detect coccidian parasites like Cryptosporidium parvum (C. parvum), C. belli, and Cyclospora species [14]. ELISA test was done to detect anti-toxoplasma IgM and IgG antibodies using (Stat Fax 2100, Awareness Technology, Inc., USA).

Complete blood picture was done for all patients with HD using (Nihon kohden 5-Part Complete Blood Count Macine,Indiamart,India)

Vascular access: it is well known that vascular access is needed for CKD children on regular hemodialysis and its complications is a very important issue when dealing with such category of patients. Three known types of vascular accesses are commonly used for HD: A-V fistula, A-V graft, and central venous catheters (CVCs). Most of our patients who had been on chronic HD for years had either A-V fistula or A-V graft that are much more suitable and less problematic for long-term HD.  CVCs were met more in patients who had problems in using their fistulas or grafts and so CVCs were used transiently till getting a well-functioning fistula or graft [15].

RESULTS

The mean age of the study cases was 14.35±4.44 years. 88% of the study cases were residents in urban areas in contrast to 75% only of the controls.

Among the cases, 36(72%) were symptomatic, most frequently with abdominal pain, vomiting, and diarrhea in proportions of (54%, 18%, and 54%, respectively), in contrast to the control group were 15(75%) symptomatic with a significant statistical difference in the diarrhea symptom; p-value (<0.001). Patients with HD showed that 8(16%) had lymph node enlargement but no significant statistical difference with the control, 14 (28%) had organomegaly and 11(22%) were exposed recently to animals with a significant statistical difference compared to the control with p-values 0.007 and 0.027 consequently. Among 50 pediatric patients with HD, we could detect B. hominis infectionin 15 patients (30%) with a significant statistical difference compared to the control group; p-value (0.004), C. parvum in 5 patients (10%), E. histolytica trophozoite in 14 patients (28%), G. lamblia cysts in10 patients (20%), Enterobius vermicularis (E. vermicularis) inone patient (2%) and Vampirolepis nana (V. nana) in none of them (0%) with no significant statistical difference compared to the control group. Among cases, anti-toxoplasma IgM was positive in one patient (2%) and reactive anti-toxoplasma IgG was found in 10 cases (20%) with no significant statistical difference when compared to the control group (Table 1).

Among cases positive for parasitic infections, male patients were 17 (48.6%) with 30 (85.7%) of the cases had an urban residency, the mean age was (14.22±4.61) years, and the mean duration of dialysis was (7.15±5.64) years but in negative cases, male patients were 6 (40%) with 14 (93.3%) had an urban residency, the mean age was (14.67±4.14) years, and mean duration of dialysis was (7.60±3.11) years. Among cases positive for parasitic infections; abdominal pain, vomiting, and diarrhea were found in 22(62.9%), 4 (11.4%), and 18(51.4%) respectively, with no significant statistical difference compared to the negative cases for parasitic infections. Lymph node enlargement, organomegaly, and animal exposure were found in 5(14%), 8(22.9%), and 7(20%) respectively, with no significant statistical difference when compared to the negative cases for parasitic infections. The mean Hb was (10.53±1.99) g/dl, the mean platelet count was (191.38 ±87.2 x10³/UL), the mean total leucocytic count (TLC) was (6.55±2.09 x10³/UL), the mean neutrophil count was (3.68±1.63 x10³/UL), the mean lymphocyte count was (2.11±.89 x10³/UL) and the median eosinophilic count was (0.39 x10³/UL) with no significant statistical difference compared to the negative cases for parasitic infections regarding all the blood picture parameters (Table 2).

In cases positive for B. hominis, 11(73.3%) had an urban residency, in contrast to 33(94.3%) in negative cases. In cases positive for B. hominis, the mean duration of dialysis was (8.77) years, abdominal pain, vomiting, and diarrhea was found in 10 patients (66.7%), one patient (6.7%), and 6 patients (40%) respectively with no significant statistical difference when compared to cases with HD negative for the same parasite. In positive patients, the median eosinophilic count was (0.40 x10³/UL), but in negative cases, the median eosinophilic count was (0.20 x10³/UL) with no significant statistical difference when compared to cases with HD negative for the same parasite(Table 3).

In positive cases for C. parvum, 5 patients (100%) had an urban residency, but in negative cases, 39 patients (86.7%) had an urban residency. In positive cases for C. parvum, the mean duration of dialysis was (5.2) years, abdominal pain, vomiting, and diarrhea were found in 3 patients (60%), 0 case (0%), and 3 cases (60%) respectively, with no significant statistical difference, compared to cases with HD who were negative for the same parasite. The blood picture parameters for cases with HD who were positive for C. parvum showedno significant statistical difference compared with cases with HD who were negative for the same parasite (Table 4).

Among cases with reactive anti-Toxoplasma IgG; the mean age was (13.95±4.35) years, the mean duration of dialysis was (7.65±4.75) years and 9 patients (90%) had an urban residency, with no significant statistical difference compared with cases with non-reactive anti-Toxoplasma IgG. In cases with reactive anti-Toxoplasma IgG; animal exposure was found in 3(30%), vascular access included 9 (90%) A-V fistula and 1 (10%) central venous catheter (CVCs), positive lymph node enlargement was found in 2 cases (20%) with no significant statistical difference compared to cases with non-reactive anti-Toxoplasma IgG but organomegaly was found in 6(60%) that showed a significant statistical difference compared with the non-reactive cases; p-value (0.020). The blood picture parameters for cases reactive for anti-toxoplasma IgG showedno significant statistical difference compared to non-reactive cases (Table 5).

DISCUSSION

The overall prevalence rate of common intestinal parasitoses among children with HD in the present study was a little bit higher than among their apparently healthy controls (70% versus 60%, respectively), but this was statistically insignificant. However, the prevalence rate of intestinal parasitic infections was 53% for the Egyptian children with HD in Zagazig University Children’s Hospital with a 36% infection rate among the control group [16].Lower infection rates with intestinal parasites among patients with HD were reported in Brazil (45.1%), Turkey (43.7%), and Iran (11.9%-30.7%)[17].

In this study, children with HD showed that B. hominis was the most prevalent protozoal infection (30%) and C. parvum was the least one (10%). On the other hand, Moawad et al. 2020 reported that C. parvum was the most prevalent among the patients with HD (13.2%) followed by B. hominis (9.6%) with the least prevalence reported for C. cayetanensis (1.5%)[16]. Gil et al.stated that Cryptosporidium species (26.4%) and B. hominis (24.5%) were the most widespread parasites that inhabit the intestine of Brazilian patients with HD[18]. Another Brazilian study also reported B. hominis as the most common parasite in patients with HD (20.1%) followed by Endolimax nana (16.3%), whereas Cryptosporidium species was reported among 4.7% of patients [19]. This concurs with a study that revealed B. hominis (4.2%-14.1%) and Cryptosporidium species (11.5%) as the most prevalent parasites among Iranian patients with HD[17].

In this study, children with HD showed that the prevalence of C. parvum was (10%), E. histolytica cyst (28%), and G. lamblia (20%). Compared with these findings, higher infection rates with Cryptosporidium species (40.0%), and lower E. histolytica (14.0%) and G. lamblia (12.0%) have been recently reported among patients with ESRD with HD in Upper Egypt [3], and also similar results were reported in Zagazig city – the capital of Sharqia Governorate- in the eastern part of Egypt where Cryptosporidium species (13.2%), E. histolytica (5.1%) and G. lamblia (2.9%) [16].

Karadag et al.stated that B. hominis (23.9%) followed by G. lamblia (8.5%) were the most prevalent parasite species among Turkish ESRD patients undergoing HD, while low rates of Cryptosporidium species and E. histolytica (2.1% each) were detected among patients [6].

These differences in the prevalence of intestinal parasitic infections among children with HD could be to some extent explained by differences in the geographical distribution of parasites in the community due to environmental, climatic, sanitary, water resources differences plus the individual differences in hygienic and behavioral factors. Also, the role of the immune status, duration of HD, and the technique of stool examination in the estimation of infection rate differences could not be excluded. Similarly, variations in the prevalence of intestinal parasitoses among apparently healthy children can be explained by the differences in the same previously mentioned factors with children undergoing HD [20].

The overall T. gondii seroprevalence rate for HD patients in this study was (22%) which is lower than those previously reported among patients with HD (61.7%) and renal transplant recipients (70.0%) in the Alexandria governorate in Egypt [21]. Uniformly, it is less than the rates recorded in Turkey (56.0%-76.5%),Mexico (56.7%), and Iran (56.7%-73.7%)[22-24].The anti-Toxoplasma IgM seroprevalence among patients with HD in this study was (2%) which is lower than that reported among Egyptian patients on regular HD (16.7%) and renal transplant recipients (24.1%) [25].Also, it is lower than those in Iranian patients undergoing regular HD in whom it was (7.8%-13.5%)[26].However, the seroprevalence rate of anti-Toxoplasma IgM among patients with HD in this study is slightly close to the rates reported from Turkey (1.7%) [24].

Comparisons can be difficult due to several factors, such as the duration of HD and the different environmental conditions. There are many obstacles in the use of molecular techniques for the diagnosis of T. gondii infection in developing countries, so, serological detection of anti-Toxoplasma antibodies is still the most commonly used approach for screening of the infection among immunocompromised patients [27]. IgG avidity test is a good technique for serodiagnosis of T. gondii as it distinguishes between acute and chronic infections. In this regard, the low avidity of specific anti-Toxoplasma IgG indicates a recent primary infection [26,28]. Also, the development of kits using immunoreactive proteins and multi-epitope antigens has been proposed for enhancing the diagnosis of T. gondii infection[29].

In this study, we found that the prevalence of E. vermicularis was (2%) among patients with HD, which was against what has been stated by Rasti et al. and Shehata et al.,where helminth larva or ova was not detected[25,26].

In this study, among the controls, E. histolytica and G. lamblia were the most prevalent but C. parvum and B. hominis were not detected. Alternatively, Gil et al.stated that B. hominis was the most prevalent species while Cryptosporidium species were not detected among the control group[18].

Regarding T. gondii, the prevalence rate of anti-Toxoplasma IgG among the control group was (15%) which was lower than that was stated by Aufy et al. but the prevalence rate of anti-Toxoplasma IgM was (0%) which was in agreement with that stated in the same study [25].

In this study, among the control group, we found that the prevalence of E. vermicularis and V. nana was (15%) and (5%) respectively, which was against what was stated by Rasti et al.and Shehata et al., where helminth larva or ova was not detected [26,30].

In this study, approximately half of the patients with HD had a significant increase in the prevalence of diarrhea but not abdominal pain or vomiting compared with the controls. On the other hand, Gil et al.stated that abdominal pain had a significant increase in patients with HD compared with the controls [18].

In this study, when we compared between cases with positive parasitic infections and those who were negative for parasitic infections, we found no statistically significant association with diarrhea, vomiting, or abdominal pain that is in congruence with what was reported among Brazilian patients with HD, where no significant association was found between parasitic infections and diarrhea[31]. Nevertheless, it is unlike the recent finding among patients with ESRD undergoing HD in Upper Egypt, where a statistical significance difference from the control group was found between the prevalence of Cryptosporidium species and diarrhea[3].

The lack or presence of association of HD with diarrhea among patients from different studies might be explained by differences in the level of immunosuppression, which determines the presence and severity of diarrhea. It is noteworthy that the differences in the incidence of gastrointestinal symptoms, including diarrhea, among patients with CKD undergoing dialysis could be largely attributed to several factors such as the levels of uremic toxins, presence of other metabolic disorders, intake of medications, and psychosocial factors[26].

 In this study, organomegaly and exposure to animals had a significant prevalence in patients with HD when compared to the controls. Alternatively, Bayani et al.stated that their patients showed no significant increase in the prevalence of organomegaly[31].

In this study, the comparison between patients positive for parasitic infections and those who are negative showed no significant difference regarding the duration of HD. This was in agreement with that stated by Mohaghegh et al. [32].

The results of this study revealed that opportunistic parasitic infections and related clinical symptoms in ESRD children undergoing HD were more frequent than in a matched control group. Considering that patients under HD are immunocompromised, parasitic infections may make their situation much more complicated.

We suggest that the stool examination for intestinal parasites, with special attention to B. hominis, should be included in the routine clinical care of patients with HD, especially in symptomatic cases. Asymptomatic cases should also undergo regular screening with stool analysis every 3 to 6 months. Measures to prevent the acquisition of intestinal parasites are also recommended. We also recommend studying the value of the prophylactic anti-helminthic treatment program applied to school children under governmental supervision, this is because we observed a low incidence of helminthic infections among the children involved in this study. It's strongly suggested that additional tests should be done, particularly for common bacterial, viral, and fungal agents known to be responsible for symptoms reported in this study. The high T. gondii seronegativity rate among patients with HD in this study indicates that the majority of these patients had not been exposed to infection and are vulnerable to the risk of acute infection that may lead to serious complications in those patients, so meticulous screening for T. gondii amongpatients with HD is strongly indicated with the introduction of new accurate tests like IgG avidity test.

Funding: None.

Conflicts of interest: None.

Ethical consideration: The study was approved by the regional ethical committee of the Department of Pediatrics, Faculty of Medicine, Ain Shams University. Also, all of the recruited patients or their legal guardians were fully informed about the study.