Strongyloidiasis: challenges in diagnosis and management in non-endemic Kuwait.

Among immunocompromised individuals, hyper-infection with Strongyloides stercoralis may occur and lead to fatal strongyloidiasis. To clinicians and laboratory diagnosticians in non-endemic countries such as Kuwait, this severe infection poses a particular problem. The clinical histories and signs and symptoms of four Kuwaiti cases of S. stercoralis hyper-infection were reviewed. Each of the four was found not only to have lived in an area where S. stercoralis was endemic but also to have been treated with immunosuppressive steroids (for medical problems unrelated to the nematode infection). When they presented with undiagnosed hyper-infections their clinical features were confusing. Three of the cases, all with low eosinophil counts, died but the other, who was treated with thiabendazole, survived. In the light of these observations, healthy medical examinees who had recently moved from endemic zones were checked for asymptomatic S. stercoralis infection, both by stool examination and ELISA-based serology. Of 381 stool samples investigated over a 3-month period, 183 (48%) were found positive for helminths, 7% for S. stercoralis. Of 198 individuals from endemic zones who were screened after another medical examination, 71 (35.8%) were found positive for intestinal helminth parasites, including one (1.45%) infected with S. stercoralis. Although ELISA appear reliable in making a presumptive diagnosis of strongylodiasis, the results of such assays are not very specific and are best interpreted in conjunction with the patient's clinical status. The concurrent administration of anthelminthics to patients prescribed steroids who, because they live or have lived in an area where S. stercoralis is endemic, are at risk of infection with the nematode, should be considered.

Cystic hydatid disease: pitfalls in diagnosis in the Middle East endemic area.

Ultrasound (US) and computerized tomography (CT) have made a significant contribution to accurately localizing focal lesions. Such imaging techniques have been found useful in assessing a hydatid aetiology of cystic lesions. However, we present 23 cases which demonstrate that these modalities in isolation are not adequate in diagnosing hydatid cysts, as claimed from this geographic area. Simple, congenital, choledochal and pancreatic pseudocysts were cystic lesions misinterpreted as hydatid cysts, as were infective disorders such as amoebiasis and tuberculosis. The appearance of a lipoma and an ovarian intra-abdominal cystadenoma and an intra-hepatic haematoma were among other conditions that were labelled as hydatid cysts on US/CT. However, in all the cyst/mass lesions that were misdiagnosed, counter-immunoelectrophoresis (CIEP), with an antigen that elicits an arc-5 in immunoelectrophoresis on cellulose acetate membranes as a substrate, did not detect any anti-Echinococcus antibodies in patients' sera. This was in contrast to the classic indirect haemagglutination test which was equivocal in some cases. The CIEP was specific and excluded hydatidosis though such a diagnosis was ventured on US and/or CT. We therefore conclude that a specific and sensitive serological test is mandatory for confirming a preoperative diagnosis of CHD. When surgery is not immediate, a negative serological test such as the CIEP would in addition indicate US or CT-guided aspiration of cyst fluid for cytological evaluation and/or enzyme immunoassay, thereby avoiding the cost and morbidity of laparotomy. Furthermore, chemotherapy is now a viable alternative provided the diagnosis is unequivocal. This may be a prudent protocol before a further decision on management is envisaged.

Analysis of the in vitro lymphoproliferative responses and antibody levels to the arc-5 antigen in patients with cystic hydatid disease.

Using a commercially-available, purified, arc-5 antigen, we examined the in vitro proliferative responses of peripheral blood mononuclear cells from hydatid patients and from healthy controls. Antibody levels of different immunoglobulin classes were also measured against the same antigen, in sera of both groups. Our findings indicate that lymphocytes from healthy controls do not proliferate to the arc-5 antigen, whereas lymphocytes from the majority of patients do. The negative or weak responses observed among a few patients were not due either to increased release of prostaglandins in culture or to a lack of responsiveness to Interleukin-2. Antibodies of all three classes, G, M and A, measured by an ELISA, were elevated in sera of patients when compared with controls. However, only levels of specific IgG antibodies gave an excellent discrimination of the disease state and these were of diagnostic value. No direct or inverse correlations between lymphoproliferative responses and antibody levels were observed in either group, although a few patients with relatively low antibody titres demonstrated very high proliferative responses. The possible use of the proliferative assay as an adjunct to serology in the diagnosis of hydatid disease is indicated.

An enzyme-linked immunosorbent assay using an arc 5 antigen for the diagnosis of cystic hydatid disease.

We report on an easily standardized enzyme-linked immunosorbent assay (ELISA) for the diagnosis of cystic hydatid disease. The antigen used is commercially available, and purified to elicit an arc 5 precipitation line by immunoelectrophoresis (IEP) with sera of patients harbouring hydatid cysts. The IgG-ELISA was highly sensitive and specific, and of diagnostic value compared to total Ig-ELISA, IgM-ELISA or IgA-ELISA. When compared to the indirect hemagglutination test and to counterimmunoelectrophoresis using an arc 5 antigen, minimal cross-reactions were observed in sera of patients with a presumptive diagnosis of hydatidosis but none were observed in those harbouring intestinal helminths, schistosomes or filarial parasites. The assay is of low cost, simple to perform, and highly reproducible. The IgG-ELISA provides an unequivocal laboratory diagnosis of hydatidosis. It is eminently suited for accurate and early identification of hydatid disease patients, for instance in mass surveys, who may benefit immediately from currently available anthelmintics, thereby obviating the need for surgery later.

Cystic hydatid disease: aspects of the incidence in man in Kuwait, Arabian Gulf.

Cystic hydatid disease (CHD) is endemic in Kuwait, but the exact extent of the disease in man has yet to be determined. The incidence was calculated by serological testing of sera from patients with a presumptive clinical diagnosis of hydatidosis and follow-up until the final diagnosis was determined. During a one-year period, 123 sera were received from two District General Hospitals serving a population of approximately 500,000. Eighteen patients had confirmed CHD, 17 were serologically positive in two tests, indirect haemagglutination (IHA) and counterimmunoelectrophoresis (CIEP), while another positive patient was identified through surgery and histopathology. These cases represent an estimated incidence rate of 3.6 per 100,000. Various factors, however, indicate that this is an underestimation of the true incidence. The infection rate of camels with hydatid cysts and dogs harbouring the adult worm, a possible measure of the true incidence in man, is considered high. Because of the nature of the population structure, the majority of patients were, in fact, non-Kuwaitis. Kuwaitis, who form 40% of the population, constituted about 30% of the CHD patients. Females were in the majority, the 21 to 50 yr. age-group being the most symptomatic. Hydatid cysts were most commonly present in the liver. Finally, compared to other countries at the time when a control programme was instituted, the incidence rate in Kuwait is moderate to high. However, the number of individuals with CHD does not appear alarming as the available capacity of the medical services is adequate.

Counterimmunoelectrophoresis using an arc 5 antigen for the rapid diagnosis of hydatidosis and comparison with the indirect hemagglutination test.

A modified counterimmunoelectrophoresis and a conventional indirect hemagglutination test were compared for routine diagnosis of human hydatid disease in an endemic area in the Middle East. Counterimmunoelectrophoresis was performed on a cellulose acetate membrane with dilutions of a commercially available antigen which interacts with sera of patients with confirmed hydatid disease to produce the arc 5 precipitin line. The test was performed with unconcentrated human sera and the lines stained in an aqueous solution of Ponceau red. Sensitivity (95.5% vs. 93.2%) and specificity (99.2% vs. 89.9%) were higher with counterimmunoelectrophoresis than with indirect hemagglutination. Cross-reactivity with sera of patients with other parasitic infections was noted with indirect hemagglutination but not with counterimmunoelectrophoresis. There was no cross-reactivity with sera of patients with autoimmune disorders by either test.