The use of direct agglutination test (DAT) in serological diagnosis of Ethiopian cutaneous leishmaniasis Asrat Hailu* Institute of Pathobiology, Addis Ababa University; PO Box 1176, Addis Ababa, Ethiopia Received 7 August 2001; accepted 29 November 2001 Abstract Leishmania aethiopica (L.a.) is the main species of Leishmania that causes Ethiopian cutaneous leishmaniasis (ECL). The routine diagnosis of ECL depends on parasitological examination of smear, culture or biopsy. In this study, DAT was set-up and evaluated for its diagnostic performance using defined sera of 45 ECL patients, 18 visceral leishmaniasis (VL) patients, 12 patients with other diseases, and 37 normal controls. The test was also evaluated in 64 patients clinically diagnosed as ECL, leprosy, or other skin diseases. Using L.a. derived antigen, the sensitivity and specificity of the test was determined to be 90.5% and 91.8% respectively. However, using antigen derived from a non-homologous strain, only 4 sera of 21 active ECL patients were positive. Eighteen sera of VL patients were positive irrespective of the different antigen sources. The data show that DAT can be a useful addition to the diagnosis of ECL. © 2002 Elsevier Science Inc. All rights reserved. Keywords: Direct Agglutination Test (DAT); Ethiopia; Leishmania aethiopica; Cutaneous leishmaniasis; Serodiagnosis 1. Introduction Leishmania aethiopica is one of the species of Leishma- nia that causes cutaneous leishmaniasis (CL). The species is restricted to the highlands of Ethiopia (Lemma et al., 1969; Ashford, 1977; WHO, 1990) and Kenya (WHO, 1990). In humans, infection by this species results in a spectrum of clinical manifestations (Bray and Bryceson, 1969) in which skin lesions are either benign and self-curing or severe and persistent (Turk and Bryceson, 1971; Belehu, 1981). The skin lesions are classified into 3 major types as localized cutaneous leishmaniasis, LCL (Lemma et al., 1969; Belehu, 1981), muco-cutaneous leishmaniasis, MCL (Barnetson et al., 1978; Belehu, 1981) and diffuse cutane- ous leishmaniasis, DCL (Bryceson, 1969; Belehu, 1981). LCL lesions are those, which evolve from small nodular lesions through the ulcerative stages to self-curing lesions that ultimately, leave behind a typical scar (Lemma et al., 1969). Parasites are usually scanty during late stages of LCL lesions (ulcers, healing lesions). Severe skin lesions that usually involve the mucous membranes of the mouth, nose, lips, cheeks, and the ears are regarded as MCL (Barnetson et al., 1978; Belehu, 1981). In such lesions, ulceration and swelling are characteristic. Parasites in MCL lesions are generally scarce, presumably due to strong antibody and delayed hypersensitivity reactions (Belehu, 1981). MCL lesions are destructive, non-self healing and difficult to treat. DCL lesions are characterized by multiple, diffuse, non-ulcerating nodular lesions (Bryceson, 1969; Belehu 1981). In contrast to LCL and MCL, parasites are super- abundant in DCL lesions. A depressed cell mediated immu- nity, but high antibody titers are characteristic features of DCL (Akuffo et al., 1987). The routine diagnosis of Ethiopian cutaneous leishman- iasis patients depends on examination of skin lesions using smears and cultures of dermal scrapings or examination of sections obtained from a skin biopsy. A large majority of CL patients reporting to dermatology clinics are LCL cases whose routine parasitological diagnosis using smears, cul- tures or biopsy is unsatisfactory (Laskay et al., 1995), be- cause smears are insensitive and cultures usually get con- taminated (Mengistu et al., 1992). Depending on the type * Corresponding author. Tel.: +1-251-1-763091; fax: +1-251-1-755296. E-mail address: aau-ipb@telecom.net.et (Asrat Hailu). www.elsevier.com/locate/diagmicrobio Diagnostic Microbiology and Infectious Disease 42 (2002) 251–256 0732-8893/02/$ – see front matter © 2002 Elsevier Science Inc. All rights reserved. PII: S0732-8893(01)00359-5