**9. Diagnosis**

Strongyloidiasis is diagnosed on the basis of suspicion in patients with clinical signs and symptoms of the disease; however, in approximately 50% of cases, the infection is asymptomatic, complicating diagnosis. In some cases, diagnosis is difficult despite a low intestinal worm load and larval excretion in the faeces (Rajapurkar et al., 2007).

The classic triad of urticaria, abdominal pain and diarrhoea is suggestive of a diagnosis of strongyloidiasis. Parasites are usually found in the faeces; they are sometimes also seen in other body fluids or in tissue samples (Basile et al., 2010). The parasitological diagnosis is usually made after an examination of the faeces, and several diagnostic methods can be used to detect *S. stercoralis*, including stool examination, a modified Baermann technique, and stool culture on a blood agar plate. Enzyme-linked immunosorbent assays (ELISA) are used for serological diagnosis and have proven valuable in detecting both symptomatic and asymptomatic strongyloidiasis infection, with a high specificity for detecting IgG antibodies to *S. stercoralis* (Basile et al., 2010).

In patients with a disseminated infection, the diagnosis is relatively straightforward, given the high numbers of larvae that exist in the stool and, usually, in the sputum. White blood

Hyperinfection Syndrome in Strongyloidiasis 389

hyperinfection syndrome can compromise the prognosis of the patient. The mortality rates of hyperinfection are high, making *Strongyloides* infection an important global health problem. It is important to understand the biology and immunology of infection with *S. stercoralis* and the altered courses of infection that may occur when immune regulation is compromised. Clinicians who are aware of the possibility of hyperinfection are better equipped to diagnose, treat, or altogether prevent the fatal consequences of this lethal

We wish to thank Elaine Medeiros Floriano for excellent technical assistance and Mara R.

**Financial support:** This study was supported by the FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) and CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico). Cristiane Tefé-Silva is supported by a scholarship through CNPq.

Abe, T., Sugaya, H., &Yoshimura, K. (1998). Analysis of T cell populations and IL-3 mRNA

Abraham, D., Rotman, H.L., Haberstroh, H.F., Yutanawiboonchai, W., Brigandi, R.A., Leon,

Al Maslamani, M.A., Al Soub, H.A., Al Khal, A.L., Al Bozom, I.A., Abu Khattab, M.J.,&

Albonico, M., Crompton, D.W.T., & Savioli, L. (1999). Control strategies for human

Anthony, R.M., Rutitzky, L.I., Urban, J.F. Jr., Stadecker, M.J., & Gause, W.C. (2007).

Armignacco, O., Capecchi, A., De Mori, P., & Grillo, L.R. (1989). *Strongyloides stercoralis*

Balagopal, A., Mills, L., Shah, A., & Subramanian, A. (2009). Detection and treatment of

Bamias, G., Toskas, A., Psychogiou, M., Delladetsima, I., Siakavellas, S.I., Dimarogona, K., &

*Infectious Disease,* Vol.11, No.2, (April), pp. 149-154, ISSN 1399-3062

*Medicine*, Vol.86, No.2, (February), pp. 258, ISSN 0002-9343

expression in mesenteric lymph node cells and intestinal intraepithelial lymphocytes in *Strongyloides ratti*-infected mice. *Journal of Helminthology,* Vol.72,

O., Nolan, T.J., & Schad, G.A. (1995). *Strongyloides stercoralis*: protective immunity to third-stage larvae inBALB/cByJ mice. *Experimental Parasitology*, Vol.80, No.2,

Chacko, K.C. (2009). *Strongyloides stercoralis* hyperinfection after corticosteroid therapy: a report of two cases. *Annals of Saudi of Medicine,* Vol.29, No.5, (September-

intestinal nematode infections. *Advances in Parasitology*, Vol.42, pp. 277–341, ISSN

Protective immune mechanisms in helminth infection. *Nature Reviews Immunology,*

hyperinfection and the acquired immunodeficiency syndrome. *American Journal of* 

*Strongyloides* hyperinfection syndrome following lung transplantation. *Transplant* 

Daikos, G.L. (2010). *Strongyloides* hyperinfection syndrome presenting as

nematode.

**13. Acknowledgments** 

**14. References** 

0065-308X

Celes and Marcela S. Oliveira for photography assistance.

No.1, (March ), pp. 1-8, ISSN 0022-149X

(March), pp. 297-307, ISSN 1090-2449

October), pp. 397-401, ISSN 0975-4466

Vol.7, pp. 975-987, ISSN 1474-1733

Simone G. Ramos and Lúcia H. Faccioli are investigators at CNPq.

cell numbers may be elevated. Although an increase in eosinophils frequently occurs during infection, studies have shown that an absence of eosinophilia does not exclude a diagnosis of strongyloidiasis (Krishnan et al., 2006). Diagnosis through imaging is usually possible. Chest radiographs of some patients have shown infiltrate consistent with Loeffler's syndrome. Methods such as bronchoalveolar lavage and sputum culture are used to diagnose disseminated strongyloidiasis (Williams et al., 1988, Yassin et al., 2010). Duodenal fluid aspiration and intestine biopsy or the use of Enterotest ® may be required to detect the *Strongyloides* parasite (Yassin et al., 2010).
