20+ Million Readerbase
Indexed In
  • Open J Gate
  • Academic Keys
  • RefSeek
  • Hamdard University
  • OCLC- WorldCat
  • Publons
  • Euro Pub
  • Google Scholar
Share This Page
Journal Flyer
Flyer image

Research Article - (2013) Volume 1, Issue 3

Eosinophil Count in Strongyloides, Hookworm, Liver Fluke or Taenia spp. Infestation

Somchai Insiripong* and Suwanna Kitsuntisumpun
Hematology Unit, Department of Medicine, Maharat Nakhon Ratchasima Hospital, Nakhon Ratchasima, Thailand
*Corresponding Author: Somchai Insiripong, Hematology Unit, Department of Medicine, Maharat Nakhon Ratchasima Hospital, Nakhon Ratchasima 30000, Thailand, Fax: 66-044-293044 Email:


 Background: It has been believed that parasites are mainly associated with eosinophilia, especially the tissue parasites. Methods: This cross-sectional study was conducted to compare the rate of eosinophilia among the healthy labors that had and did not have parasites. Results: Among 1,337 labors, the eosinophilia was found in 16 of 69 individuals with parasites (23.2%) and in 266 of 1,268 without parasites (21.0%). By Chi-square test, there was no statistically significant difference, (p 0.661). When the parasites were categorized into: Strongyloides, hookworm, liver fluke and Taenia spp., the rate of eosinophilia in patients with each parasite was not different from each other or from the individuals without parasites. Conclusion: The prevalences of eosinophilia among individuals with parasites including Strongyloides, hookworm, liver fluke or Taenia spp. infestation and those without parasites are not different.

Keywords: Eosinophilia; Strongyloides; Hookworm; Liver fluke; Taenia spp


The eosinophilia is defined as the absolute eosinophil count of more than 500 cells/mm3 [1] and one of its outstanding causes is the parasitic infestation [2-4]. However, eosinophilia seems to be more strongly associated with the tissue parasites and the larval phase than the adult phase of the intestinal parasites. The tissue parasites such as F. hepatica and hydatid cyst can cause eosinophilia, ranging from 770 to 10,560 cell/mm3 and 825 to 2,970 cell/mm3 respectively [5]. Whereas the intestinal parasites such as hookworm, when the volunteer was purposely infected by N. americanus, the eosinophil was increased from 300/mm3 (41.5% of WBC) to 6,370/mm3 (41•5% of WBC) on day 42 after percutaneous infection before declined to a persistently elevated level of around 1,600/mm3 (18% of WBC). During the second infection, there was a transient increase in eosinophil, peaking at 3,380/ mm3 at day 46 after infection [6]. The resemble study performed in Australia showed the eosinophil peaked at 1,910/mm3 during week 4 and then gradually declined to a plateau at week 9 [7]. Focusing on the adult hookworm infection, the eosinophilia can be found in 87.5% of 32 hookworm cases, compared with 63.1% of 19 normal people [8] while in another study, the eosinophilia is found in 30 to 60% of hookworm cases [9]. For strongyloidiasis, only 12 from 20 patients (60.0%) had eosinophilia [10]. It appears that the frequencies of eosinophilia in any parasitic infestation from various studies cannot be undoubtedly conclusive. The aim of this study was to find and to compare the blood eosinophil count between the participants whose stools had larvae of Strongyloides or ova of hookworm, liver fluke and Taenia spp and that of the normal people.

Materials and Methods

This cross-sectional study was conducted at the department of medicine, Maharat Nakhon Ratchasima Hospital. The participants were the healthy laborers who lived in town and would like to work abroad, seeking for the certificate of health between March 2112 and August 2112. All of them were 20 years of age or older and their physical examinations were all normal. Prior to enrollment, informed consent was obtained from all participants. Many investigations including CBC, BUN, creatinine, FBS, uric acid, lipid profile, liver function test, anti-HIV, VDRL, HBsAg, anti-HCV, urinalysis and stool examination were routinely performed. The imaging included the chest film and the ultrasonography of the whole abdomen. CBC was performed using the automated hematology analyzer, Coulter® STKS, while the stool was examined for only one time, exclusively using the simple concentration smear method within the same day.

The labourers who were found to have any laboratory abnormality would be excluded.

The labourers who had parasitic larvae or ova in the stool were recruited whereas the rest of the laborers who did not have any parasite were used as the control group. The prevalence and types of the parasites were recorded and the eosinophil count among participants whoever had any kind of parasite would be compared with that of the control.

The data were analyzed with chi-square test. If the p-value was less than 0.05, it would be considered statistically significant.

The study was approved by the ethic committee of Maharat Nakhon Ratchasima Hospital.


There were 1,337 laborers, consisting of 1,243 males (93.0%) and 94 females (7.0 %). Ages ranged from 18 to 57 years, mean 37.5 years. The general demographic data and hemoglobin concentration (Hb), WBC and eosinophil count were shown in the Table 1.

  Minimum Maximum Mean + SD
Age (years) 18 57 37.5 ± 3.5
Hb conc (g%) 9.8 18.0 14.5 ± 1.1
WBC (/mm3) 3,000 17,300 7,773 ± 8.8
Eosinophil count (/mm3) 0 5,733 359.1 ± 10.8

Table 1: The general characteristics of the participants.

Out of 1,337 participants, 69 cases (5.2%) were found to be infected with various kinds of parasites as follows: 57 with Strongyloides stercoralis (4.3%), 6 with hookworm (0.4%), 3 with liver fluke (0.2%), and 3 with Taenia spp. (0.2%). Only 16 of 69 patients with parasites (23.2%) were found to have blood eosinophilia, compared with 266 from 1,268 participants (21.0%) who did not have any parasite, had eosinophilia. The percentage of eosinophilia from both groups were compared and analyzed with Chi-square test, as shown in Table 2.

  Present eosinophilia Absent eosinophilia Total
Present parasite 16 (23.2%) 53 69
Absent parasite 266 (21.0%) 1,002 1,2681,002
Total 282 1,055 1,337

Table 2: The association between the parasite and the eosinophilia.

Chi-square was 0.192, p value for 2-tailed was 0.661. The prevalence of eosinophilia from the group with parasites was different from that of the normal control group without statistic significance.

When the participants who harbored each parasite were allocated into 2 groups, with the eosinophilia (eosinophil >500 cells/mm3) and without the eosinophilia, the prevalences of the eosinophilia among each parasite were compared with that of the participants who did not have parasite, using chi-square, shown in the Table 3.

Parasite with eosinophilia without eosinophilia p value
S. stercoralis (57) 12 (21.1%) 45 (78.9%) 0.989
Hookworm (6) 3 (50%) 3 (50%) 0.082
Liver fluke (3) 0 3 (100%) 0.372
Taenia spp. (3) 1 (33.3%) 2 (66.6%) 0.600
No parasite (1268) 266 (21.0%) 1002 (79.0%)  

Table 3: The participants with each parasite and the eosinophilia Numbers (%).

The prevalence of eosinophilia among the participants with S. stercoralis, hookworm or Taenia spp. was different from that of the participants without parasite without statistic significance while none of three participants with liver fluke did have eosinophilia.


The prevalences of eosinophilia among participants who had and had not parasites including S. stercoralis, hookworm (mainly Necator americanus [11]), liver fluke (mainly Opisthorchis viverrini [12]) and Taenia spp., did not differ from each other (p value 0.65), probably because the parasites we concerned were adult forms. In the early stage of larval invasion, parasites can act as potent immunologic stimuli, resulting in the eosinophilia while in the late stage of encystment or adult form, they become immunologically silent and asymptomatic, leading to the subsidence of the eosinophilia. Such a biphasic pattern is seen in new infections with various parasites including Opisthorchis [13]. Mawhorter [14] claims that only tissue-invasive helminthic parasites can cause eosinophilia, and suggests that the use of eosinophilia as a screening tool for parasitic infections is very limited [14,15].

Meeusen and Balic review so many studies and conclude that eosinophils can kill only the larvae, but not adult, of most helminthic parasites [16], probably by depositing cationic proteins possessing helminthotoxic activities from their granules, on the surface of the larvae [17]. Then the eosinophilia spontaneously decreases in numbers even in the absence of treatment after the larvae become mature adults [18].

In fact the people in endemic area who harbor parasites always have multiple more than single helminthes [19,20]. The cause of the eosinophilia in any individual who has intraluminal parasites may be truly the tissue parasites or larval stage of the intraluminal parasites. Zawawy et al. show that the helminthic cause of eosinophilia of only 9 from 53 patients can be diagnosed with the stool examination. With the immunoelectrophoresis for tissue parasite antigen, the helmithic cause can be identified up to 37 cases, because some of them do not pass ova into the stool [5]. And also Seybolt et al. show that parasite is identified in stool of only 29% of eosinophilia while the serology for Strongyloides is more common, up to 39% [21]. Furthermore, Goswami shows that in eosinophilia without an intraluminal parasite, the sera tests are still positive to Strongyloides and their eosinophilia responds well to ivermectin [22].

Because tissue parasites play role to cause eosinophila more than intra-luminal parasites [23], our 266 workers who had eosinophilia without parasite in the stool, were treated with albendazole which was proved to be effective in cases of eosinophilia [1].


The prevalence of eosinophilia of participants with strongyloides, hookworm, liver fluke or Taenia spp. is similar to that of the participants without parasite. All these parasites are not responsible for the high prevalence of eosinophilia that is around one-fifth of this population.


We would like to express our gratitude to the research center of Maharat Nakhon Ratchasima Hospital for their grant.


  1. Tefferi A (2005) Blood eosinophilia: a new paradigm in disease classification, diagnosis, and treatment. Mayo Clin Proc 80: 75-83.
  2. Nutman TB, Ottesen EA, Ieng S, Samuels J, Kimball E, et al. (1987) Eosinophilia in Southeast Asian refugees: evaluation at a referral center. J Infect Dis 155: 309-313.
  3. Pardo J, Carranza C, Muro A, Angel-Moreno A, Martín AM, et al. (2006) Helminth-related Eosinophilia in African immigrants, Gran Canaria. Emerg Infect Dis 12: 1587-1589.
  4. el Zawawy LA, el Nassery SF, al Azzouni MZ, Abou el Naga IF, el Temsahi MM, et al. (1995) A study on patients with eosinophilia of suspected parasitic origin. J Egypt Soc Parasitol 25: 245-255.
  5. Wright V, Bickle Q (2005) Immune responses following experimental human hookworm infection. Clin Exp Immunol 142: 398-403.
  6. Landmann JK, Prociv P (2003) Experimental human infection with the dog hookworm, Ancylostoma caninum. Med J Aust 178: 69-71.
  7. Triteeraprapab S, Nuchprayoon I (1998) Eosinophilia, anemia and parasitism in a rural region of northwest Thailand. Southeast Asian J Trop Med Public Health 29: 584-590.
  8. Kucik CJ, Martin GL, Sortor BV (2004) Common intestinal parasites. Am Fam Physician 69: 1161-1168.
  9. Kitchen LW, Tu KK, Kerns FT (2000) Strongyloides-infected patients at Charleston area medical center, West Virginia, 1997-1998. Clin Infect Dis 31: E5-6.
  10. Jiraanankul V, Aphijirawat W, Mungthin M, Khositnithikul R, Rangsin R, et al. (2011) Incidence and risk factors of hookworm infection in a rural community of central Thailand. Am J Trop Med Hyg 84: 594-598.
  11. Traub RJ, Macaranas J, Mungthin M, Leelayoova S, Cribb T, et al. (2009) A new PCR-based approach indicates the range of Clonorchis sinensis now extends to Central Thailand. PLoS Negl Trop Dis 3: e367.
  12. MacLean JD, Graeme-Cook FM (2002) Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 12-2002. A 50-year-old man with eosinophilia and fluctuating hepatic lesions. N Engl J Med 346: 1232-1239.
  13. Mawhorter SD (1994) Eosinophilia caused by parasites. Pediatr Ann 23: 405, 409-413.
  14. Molinier S, Chaudier B, Kraemer P, Graffin B, San VV, et al. (1998) Diagnostic and treatment of hypereosinophilia upon return from the tropics: 102 patients. Med Trop (Mars) 58(Suppl 4): 499-502.
  15. Meeusen EN, Balic A (2000) Do eosinophils have a role in the killing of helminth parasites? Parasitol Today 16: 95-101.
  16. Wardlaw AJ (1994) Eosinophils in the 1990s: new perspectives on their role in health and disease. Postgrad Med J 70: 536-552.
  17. Klion AD, Nutman TB (2004) The role of eosinophils in host defense against helminth parasites. J Allergy Clin Immunol 113: 30-37.
  18. Kitvatanachai S, Rhongbutsri P (2007) Helminth infections in some areas of Thailand where Strongyloides is prevalent. J Trop Med Parasitol 30: 12-17.
  19. Waikagul J, Krudsood S, Radomyos P, Radomyos B, Chalemrut K, et al. (2002) A cross-sectional study of intestinal parasitic infections among schoolchildren in Nan Province, Northern Thailand. Southeast Asian J Trop Med Public Health 33: 218-223.
  20. Seybolt LM, Christiansen D, Barnett ED (2006) Diagnostic evaluation of newly arrived asymptomatic refugees with eosinophilia. Clin Infect Dis 42: 363-367.
  21. Goswami ND, Shah JJ, Corey GR, Stout JE (2009) Persistent eosinophilia and Strongyloides infection in Montagnard refugees after presumptive albendazole therapy. Am J Trop Med Hyg 81: 302-304.
  22. Insiripong S, Siriyakorn N (2008) Treatment of eosinophilia with albendazole. Southeast Asian J Trop Med Public Health 39: 517-520.
Citation: Insiripong S, Kitsuntisumpun S (2013) Eosinophil Count in Strongyloides, Hookworm, Liver Fluke or Taenia spp. Infestation. Trop Med Surg 1:127.

Copyright: © 2013 Insiripong S, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.