Comparison of Methods in the Serologic Diagnosis of Cystic Echinococcosis

Acta Parasitologica (2024) 69:1122–1131 https://doi.org/10.1007/s11686-024-00840-z ORIGINAL PAPER Comparison of Methods in the Serologic Diagnosis of Cystic Echinococcosis Sidre Erganis1 · Fakhriddin Sarzhanov2,3 · Funda Doğruman Al2 · Kayhan Cağlar1 Received: 8 July 2023 / Accepted: 20 March 2024 / Published online: 29 March 2024 © The Author(s) 2024 Abstract Purpose Cystic echinococcosis (CE) is caused by the larval form of Echinococcus granulosus. Clinical, radiologic, pathologic, and serologic findings should be evaluated together for the diagnosis of CE. The sensitivity and specificity oalf serologic tests may vary depending on the method used. In this study, we aimed to detect IgG antibodies specific to E. granulosus using indirect hemagglutination assay (IHA), enzyme-linked immunosorbent assay (ELISA), indirect fluorescent antibodies (IFA) and western blot (WB) tests. Methods In our study, the serum samples of 74 patients sent to our laboratory with suspicion of CE were studied using two different commercial IHA tests, ELISA, IFA and WB test. The test results were evaluated along with radiological findings and histopathological examinations, the latter being the gold standard. Results Of all the patients, 51 (69%) were female and 23 (31%) were male. There was a statistically significant difference between males and females (χ2 = 9.7, p = 0.002). Out of 74 patients, positivity rates for Siemens IHA, Fumouze IHA, ELISA, IFA and WB test were positive as 33 (44.6%), 35 (47.3%), 43 (58.1%), 42 (56.7%) and 38 (51.3%), respectively. The sensitivity and specificity of the tests were as follows: 66.67 and 2.31% for Siemens IHA; 70.83% and 96.15% for Fumouze IHA; 85.42%, and 88.46% for ELISA; 83.33% and 88.46% for IFA; 72.92% and 88.46% for WB test. Conclusion There were statistically significant differences in between all five methods (p < 0,001). While the tests with the highest specificity was Fumouze IHA, the test with the highest sensitivity was the ELISA test. It was concluded that IHA and ELISA tests were more practical in practice because of their greater applicability. Keywords Anti-Echinococcus IgG · Cystic echinococcosis · Hydatid cyst · Serologic diagnosis Sidre Erganis Fakhriddin Sarzhanov Abbreviations IHA Indirect Hemagglutination ELISA Enzyme-linked Immunosorbent Assay IFA Indirect Fluorescent Antibodies WB Western Blot CE Cystic Echinococcosis Funda Doğruman Al Introduction Kayhan Cağlar Echinococcosis is a parasitic infection that occurs in humans and animals. The adult form of Echinococcus granulosus sensu lato (s.l.) is found in the small intestine of the definitive hosts such as dogs, wolves, and jackals [1]. Echinococcus granulosus sensu lato has different subtypes with different host specificities: E. granosus sensu stricto (s.s.) (G1-G3), Echinococcus felidis, Echinococcus equinus, Echinococcus ortleppi, and Echinococcus canadensis (G6/G7, G8, and 1 Department of Medical Microbiology, School of Medicine, Gazi University, 06490 Ankara, Türkiye 2 Division of Medical Parasitology, Department of Medical Microbiology, School of Medicine, Gazi University, 06490 Ankara, Türkiye 3 Faculty of Medicine, Akhmet Yassawi International KazakhTurkish University, 161200 Turkestan, Kazakhstan 13 Acta Parasitologica (2024) 69:1122–1131 G10) [2]. The larval form causes cystic echinococcosis (CE) that is located in the internal organs of many mammals such as sheep, goats, cattle, and humans. Intermediate hosts usually become infective by ingesting infective eggs excreted with the feces of the definitive host. It may produce a variety clinical symptoms or may be asymptomatic or show no symptoms depending on the location and size of the cyst. It is a neglected zoonosis, which is an important public health problem in many regions of the world and our country due to the socio-economic losses it causes [1, 3, 4]. Humans are defined as incidental hosts and not essential to the parasite’s life cycle. However, if the disease is left untreated, it has significant social and economic consequences, as well as serious morbidity and mortality. Estimated data on the global distribution of the disease show that CE affects 2–3 million people and there are 200,000 new cases every year [3]. According to the data of WHO, worldwide, CE causes about 19,300 deaths per year [5]. The exact number of all CE cases is difficult to estimate in Türkiye because data on the prevalence of CE in Türkiye is based on screening studies involving a small and limited number of population and cases usually reported by hospital records [6]. A study under the Heracles (Human cystic echinococcosis ReseArch in CentraL and Eastern Societies) Project investigated rural areas of Bulgaria, Romania, and Türkiye by ultrasound-based screening. In the study, abdominal CE was found in 53 (0.6%) of the total of 8618 people in villages belonging to six provinces of Türkiye. It is known that this study is the most comprehensive screening in Türkiye to date [6, 7]. It is estimated that the disease is much more common than previously thought because of the uncharacteristic clinical symptoms, very slow cyst development, and the problems in making a definitive diagnosis of the disease [4, 8]. Currently, the diagnosis of CE is mainly suggested by radiologic diagnostic methods. Ultrasonography imaging is often used because it allows staging of cysts [6]. In order to make a differential diagnosis of the cysts from other spaceoccupying lesions like tumors, abscesses, simple cysts, and to evaluate the recurrence after treatment accurately, the preliminary diagnosis should be supported using serological diagnostic methods such as indirect hemagglutination (IHA), immunofluorescent antibody test (IFA), enzyme immunosorbent linked assay (ELISA). The study of the genome of the parasite in recent years as a result of the advances in molecular biology has created opportunities to explore new approaches in understanding the biology, diagnosis, and treatment options of the parasite [9, 10]. In this study, it was aimed to detect E. granulosus specific immunoglobulin IgG antibodies in the sera of suspicious CE patients admitted to Gazi University Hospital by 1123 using various serological tests such as IHA, ELISA, IFA and WB. Materials and Methods A total of 74 serum samples from the patients with CE based on the clinical and radiologic findings between June 2018 and June 2019 were submitted to the Clinical Microbiology Laboratory of Gazi University Hospital. All of the 74 serum samples were taken at the time of diagnosis. Patients diagnosed as CE by radiological imaging (such as ultrasonography, computed tomography or magnetic resonance imaging) or by histopathologically were selected in our study. Non-CE cases mentioned in our study were those that were pre-diagnosed as CE on a radiological basis but whose histopathological examination reports were not interpreted as CE. Anti-Echinococcus granulosus anti (...truncated)