Prevalence of cystic echinococcosis in slaughtered livestock in Iran: a systematic review and meta-analysis

Advances in Detecting Cystic Echinococcosis in Intermediate Hosts and New Diagnostic Tools: A Literature Review

Cystic echinococcosis (CE) is a zoonotic disease affecting humans and animals. Despite a lack of clarity about many details of parasite-intermediate host interactions, the nature of the immune responses triggered by hydatid infection has revealed new perspectives. This study discusses the latest advances in elucidating the immunologic mechanism of echinococcosis and its detection and potential approaches to enhance serodiagnosis accuracy. Moreover, nanobiosensors have been evaluated according to their potential to improve treatment efficiency and aid in an early diagnosis of cystic echinococcosis. The serum of an intermediate host can diagnose CE by analyzing antibodies induced by Echinococcus granulosus. Among the most notable features of this method are its noninvasive ability and high sensitivity, both of which make it an excellent tool for clinical diagnosis. Several serological tests, including ELISAs and immunoblotting, can detect these antibodies to assess the disease's state and determine the treatment outcome. A thorough understanding of what cross-reactivity means and the stage of the disease are crucial to interpreting serological results. Nanobiosensors have also proven better than conventional biosensors in detecting hydatid cysts. Additionally, they are highly sensitive and versatile when detecting specific biomarkers, improving diagnostic accuracy. These immunomodulatory molecules, induced by E. granulosus, are a good candidate for diagnosing cystic echinococcosis because they alter intermediate host immune responses. Hydatid cyst detection is also enhanced through nanobiosensors, which provide better accuracy.

Epidemiological characteristics of human cystic echinococcosis in Khuzestan province (Iran), 2011-2021: a retrospective analytical study

Hydatid cyst (HC) disease is endemic in many Mediterranean countries. The most polluted areas of Iran include the Alborz and Zagros Mountain ranges, where animal husbandry is common. This study investigated the epidemiological dimensions of HC in patients admitted to hospitals in Khuzestan province from 2011 to 2021. Of all 183 patients identified, 113 (61.7%) were female with the mean age of 37.7 ± 17, men with the mean age of 36.7 ± 19. Also, we found that housewives made up 49.2% of our HC patients. 65% of the patients in this study lived in urban areas, and 42% had a history of contact with dogs. The liver was reported to be the most HC-affected organ. The most clinical symptoms were abdominal pain and hepatomegaly. 59% of the patients had only one cyst. This study found that surgery and radiology were the most common treatment and diagnostic methods. There were significant relationships between: gender and occupation (p < 0.001); location with dog contact, duration of dog contact (p < 0.001); ways of washing raw vegetables (p < 0.01), and type of treatment (p < 0.05); occupation and dog contact (p < 0.001); with the involvement of the liver being greater in patients who used only water to wash vegetables (p < 0.01). The key to successful disease management is early diagnosis. How to intervene and treat HC necessitates the identification of the stages of the cyst, which is dependent on imaging techniques. The prevalence of human hydatidosis has been overlooked as the most important disease that health policymakers should consider. Furthermore, training programs are required to better understand the disease's symptoms and identify sources of infection.

Evaluation of Hydatid Cyst Antigen for Serological Diagnosis

Background

Hydatidosis, a chronic zoonotic disease, has a distribution worldwide and is caused by the larval stage of the Echinococcus helminth. The Dot-ELISA test can diagnose hydatidosis quickly and accurately. Additionally, unlike other hydatid disease tests now used, this quick and affordable enzyme immunoassay is very serum-conservative and antigen-conservative, needing just nanogram levels of parasite antigen.

Methods

In the present cross-sectional study, crude and B antigens of hydatid cyst fluid were obtained to diagnose human hydatidosis using CIEP (Counter Immunoelectrophoresis), ELISA (Enzyme-linked Immuno Sorbent assay), and Dot- ELISA (Dot Enzyme linked Immuno Sorbent Assay) methods. Infected liver with a hydatid cyst was collected from Tehran's slaughterhouses to prepare cyst fluid in different stages. After extracting and purifying the Cyst fluid, it is centrifuged at 4ºc, then prepared to concentrate. The study also included sera from hydatidosis (n=60), samples of helminth parasites (n=55), fascioliasis (n=35), toxocariasis (n=20) and negative control (n=35) were tested by CIEP (Counter Immunoelectrophoresis), ELISA (Enzyme-linked Immune Sorbent assay), and Dot- ELISA (Dot Enzyme linked Immuno Sorbent Assay) methods. All statistical analyses were performed using Statistical Package for the Social Sciences (SPSS) for Windows release 25.0 (SPSS Inc., Chicago, IL, USA).

Results

Crude antigen of hydatid cyst showed a specificity of 76.7%, a sensitivity of 93.3% using the ELISA method, and B antigen showed a specificity of 96.7% and sensitivity of 88.3% using the same method. The crude antigen of the hydatid cyst exhibited a specificity of 68.9% and a sensitivity of 86.7% using CIEP. The B antigen showed a specificity of 87.8% and sensitivity of 83.3% using the same method.The crude antigen of hydatid cyst having serum dilution at 1:800 exhibited a specificity of 83.3% and sensitivity of 100% using the Dot-ELISA method and B antigen having serum dilution at 1:800 serum showed a specificity of 100% and sensitivity of 98.3% using the same method. The results of this finding showed that B antigen has the maximum specificity to diagnose hydatid test using the Dot- ELISA method.

Conclusion

Hydatid cysts present with varied symptomatology. History of exposure to infected animals may not be present. A high degree of clinical suspicion combined with meticulous history and clinical examination supported by laboratory investigations are required for its diagnosis. The Dot-ELISA system with native antigen B is a viable approach for the immunodiagnosis of human hydatidosis that is preferred to infection.

Tension pneumothorax caused by the ruptured hydatid cyst of the lung

Hydatid cyst disease puts a significant burden on the health of humans every year. The lung is the second most common organ of implantation of Echinococcus larvae. Due to the importance of early diagnosis of tension pneumothorax, this paper provides four cases of hydatid disease that presented with tension pneumothorax.

IEg67 kDa Bovine Hydatid Cyst Antigen: A Candidate for Developing Sero-Diagnostic Assays for Cystic Echinococcosis, a Disease of One Health Importance

Cystic echinococcosis (hydatidosis) is a world-wide zoonotic disease of mainly humans, livestock and dogs, caused by Echinococcus granulosus. The disease can negatively impact food production and animal welfare and causes socio-economic hardship. Here, we aimed to identify the local bovine hydatid cyst fluid (BHCF) antigen for developing a sero-diagnostic assay to be used for the pre-slaughter screening of food animals. In total, 264 bovines approved for slaughter in Pakistan were subjected to serum collection and post-mortem screening for hydatid cysts. These cysts were assessed microscopically to assess fertility and viability, and by PCR for molecular confirmation of species. A BHCF antigen was identified from positive sera via SDS-PAGE, confirmed by Western blot, and quantified via a bicinchoninic acid (BCA) assay. The quantified crude BHCF antigen (iEg67 kDa) was then used in ELISA screening to test all sera collected from known positive and negative animals based on hydatid cyst presence/absence. Of the 264 bovines examined, 38 (14.4%) showed hydatid cysts during post-mortem examination. All of these individuals, plus an additional 14 (total: 52; 19.6%) tested positive based on less time-consuming ELISA examination. Based on ELISA, occurrence in females (18.8%) was significantly higher than in males (9.2%) and was higher in cattle (19.5%) compared to buffalo (9.5%). The infection rate increased with age in both host species: cumulatively, 3.6% in animals aged 2-3 years, 14.6% in 4-5-year-olds and 25.6% in 6-7-year-olds. The occurrence of cysts in cattle was significantly higher in the lungs (14.1%) compared to their livers (5.5%), whereas the opposite was true in buffalo (6.6% livers, 2.9% lungs). For both host species, most cysts in the lungs were fertile (65%), while the majority in the liver were sterile (71.4%). We conclude that the identified iEg67 kDa antigen is a strong candidate for the development of a sero-diagnostic screening assay for the pre-slaughter diagnosis of hydatidosis.

The occurrence of cystic echinococcosis in slaughtered livestock in Jahrom, south of Iran

Cystic echincoccosis (CE) is a major medical and veterinary concern in the world, especially in Iran. Domestic intermediate hosts are an important reservoir for the disease spread. The purpose of this study was to determine the prevalence of CE in slaughtered livestock in Jahrom, south of Iran. In this cross-sectional study, a total of 3074 animals (2325 (75.63%) goats, 423 (13.76%) sheep, and 326 (10.60%) cattle) were inspected macroscopically for CE. In this regard, a questionnaire about the age, sex, infected organ, number of cysts, and cyst fertility was accomplished for each animal. Moreover, PCR was applied by using the cytochrome c oxidase I (COX1) and NADH dehydrogenase subunit 1 (nad1) fragments of parasite mitochondrial genomes on some positive samples. Prevalence of CE in sheep, cattle, and goats was 11.34% (48/423), 11.04% (36/326), and 2.79% (65/2325), respectively. In all livestock, CE was more common in females than males. Moreover, the highest infection rate was observed in the age group of more than 72 months. Considering the fertility of cysts, the ratio of the number of fertile cysts to total cysts in sheep and goats were 83.3% (40/48) and 80% (52/65), respectively. All hydatid cysts were infertile in cattle. With regard to the location of the cyst on internal organs, the most were observed in the lungs and liver. Regarding the intensity of infection, 1–5, 6–9 and ≥ 10 cysts were detected in 78.52% (117/149), 6.71% (10/149) and 10.73% (16/149) of infected livestock, respectively. In all livestock, hydatid cyst with a diameter of 1–5 cm was the most frequent with 71.81% (107/149). All 149 cyst samples were subjected to PCR. Among them, a total of 18 samples (six samples of each animal) were prepared for sequencing. G6 was the most dominant. According to the results of present study and the relatively high prevalence of CE in slaughtered livestock in Jahrom, health policy makers, health authorities, and experts should make effective approach in this regard, and implement careful inspections.

Meta-analysis of the prevalence of bovine cystic echinococcosis in China during decade

BACKGROUND

Cystic echinococcosis (CE) is a zoonotic parasitic disease caused by Echinococcus granulosus sensu lato (E. granulosus s.l.) larvae. It is mainly prevalent in western agricultural and pastoral areas in China, seriously affecting the development of public health and animal husbandry.

METHODS

This study conducted a systematic evaluation and meta-analysis of bovine CE in China in the past 10 years (2011-2020). Five databases (PubMed, ScienceDirect, CNKI, Wanfang Data, VIP Chinese Journal Database) were used to collect the relevant references, and finally 77 published articles were obtained.

RESULTS

The total prevalence of bovine CE was estimated to be 9.62% during decade, and decreased year by year after reaching its peak in 2014 (18.75%). The highest E. granulosus s.l. infection rate was found in Qinghai province (14.79%). The infection rate of cattle >4 years old (15.84%) was significantly higher than that of other age groups, and cattle raised by grazing was significantly higher than that of other methods (17.00%). In the groups of geographical and climatic factors, the prevalence of CE was higher in regions with high-altitude (20.76%), cold (20.76%) and rainy areas (11.33%).

CONCLUSION

This study found that old age and grazing were two important factors for the high incidence of bovine CE. The prevalence of CE is higher in low temperature, rainy and high altitude areas, where may be more suitable for the survival of E. granulosus s.l. eggs.

Bacterial and Fungal Occurrence in Hydatid Cysts from Livestock in Central Iran

Echinococcus granulosus sensu lato causes Cystic echinococcosis. This study investigated the bacterial and fungal species in the liver and lung hydatid cysts obtained from sheep, goats, cattle, and camels slaughtered in Yazd abattoir, Central Iran. In this study, 84 hydatid cysts were obtained from 20 sheep, 13 goats, 25 cattle, and 26 camels. The fertility and viability rates were assessed using light microscopy and eosin staining, respectively. The aspirated hydatid cysts were cultured to detect the presence of any bacteria and fungi. Bacterial isolates were identified by biochemical tests. DNA was also extracted from germinal layers, and then genotyping was carried out targeting the cox 1 gene. The statistical analysis was performed by SPSS version 16.0. This study showed that 22.62% (19/84) of hydatid cysts had bacterial occurrence, and none of the samples had fungal species. Among the fertile cysts, 52.6% had bacterial occurrence, of which 40% were viable. Most bacteria detected in hydatid cysts included Staphylococcus saprophyticus, Escherichia coli, and S. epidermidis. Hydatid cysts with bacterial occurrence were identified as G1-G3, G5, and G6/G7. The bacterial species occurrence in hydatid cysts had no significant relationship with fertility and viability (P > 0.05), without any significant relation with viability (P > 0.05), animal species (P > 0.05), involved organ in animals (P > 0.05), and hydatid cyst genotypes (P > 0.05). It should also be mentioned that this is the first study to assess the relationship between hydatid cyst genotyping and the occurrence of fungal and bacterial species.