The enzyme-linked immunosorbent assay (ELISA) was used to examine sera of 104 Key words: seroprevalence -Toxocara -enzyme-linked immunosorbent assay -Nigeria Toxocara canis is a saprozoonotic parasite capable of infecting man. Infection in man follows the ingestion of embryonated eggs of the parasite with subsequent hatching and migration of the larvae in his tissues. The persistence or migration of T. canis in the tissues of man causes visceral larva migrans, VLM (Beaver 1969).The diagnosis and confirmation of human toxocariasis rely heavily upon serological tests. In this respect the enzyme-linked immunosorbent assay (ELISA) developed by Cypess et al. (1977) and modified by Glickman et al. (1978) has been found to be very useful in different parts of the world (De Savigny et al. 1979, Glickman et al. 1979, Matsumura & Endo 1983, Garcia et al. 1989, Abo-Shehada et al. 1992, Hakim et al. 1992, Chomel et al. 1993, Holland et al. 1995 because of its high sensitivity and specificity in the routine diagnosis of human toxocariasis.The purpose of this paper is to report on the first serological diagnosis of human toxocariasis in Nigeria and the importance of the disease as a public health problem in the tropical environment. MATERIALS AND METHODSSerum samples -The sera of 104 subjects comprising of 54 males and 50 females, aged between 2 and 24 years were collected between June 28 and July 4 1996. Twenty two of the subjects (15 This work was supported in part by the Faculty of Natural Sciences, University of Jos, research grant no. UJ/ FNS/RG/94-95/13. + Corresponding author. E-mail: ajayi j @ unijos.edu.ng Received 6 April 1999 Accepted 11 November 1999 males and 7 females) were inpatients of the Jos University Teaching Hospital, 58 (29 males and 29 females) were pupils of the Jos University Primary School, 15 (5 males and 10 females) were students of the Jos University Demonstration Secondary School, and 9 (5 males and 4 females) were volunteers. Before the collection of sera, signed consent were obtained from the subjects or their parents or guardians. Information about geophagia (soil pica) and dog ownership were obtained by direct interrogation of the subjects and or their parents or guardians. Six of the subjects had parasitological proven helminthiasis which included ascariasis, taeniasis, trichuriasis and hookworm infections.After collection, serum samples were stored at -20 o C until required.Positive and negative control sera and Toxocara ES antigen were gifts from Dr Guus Van der Lugt, Institute of Infectious Diseases and Perinatal Screening, Bilthoven, The Netherlands.The ELISA -The ELISA was carried out in two 96 well polystyrene microtitre plates (Maxisorb, Nunc, Weisbaden, Germany). An amount of 100 µl of the antigen diluted 1:30 in carbonate buffer, pH 9.6 was added to each well. Then the plates were left opened and incubated overnight at 37 o C. The plates were washed five times with phosphate buffered saline (PBS) containing 0.05% Tween 20 (PBST). After discarding the washing fluid, 100 µl of the ...

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