The Influence of Selected Factors on the Detection of Giardia intestinalis by Microscopic and Immunoenzymatic Methods

Background

Giardia intestinalis is one of the most common parasites in humans. Contaminated food and water can be a source of infection. Substances added to food are intended to increase its safety. We aimed to determination of the influence of various microorganisms and compounds that stimulate digestive functions, as well as preservatives and antioxidants on the detection of G. intestinalis by microscopic and immunoenzymatic methods.

Methods

Twenty stool samples, archived in 1998-2018 in the Provincial Sanitary and Epidemiological Station in Bydgoszcz (Poland), collected both from patients referred for parasitic examinations by a doctor of a medical facility and from private individuals, were used to assess the impact of selected factors (such as bacterial strains, viruses and substances added to food) on the detection of G. intestinalis by microscopic and immunoenzymatic methods.

Results

G. intestinalis was detected by both microscopic and immunoenzymatic methods with the same sensitivity (100%). The result of the G. intestinalis determination was positive in 90% of the samples after the addition of potassium sorbate, and in 25% of the samples after the addition of citric acid.

Conclusion

The presence of other microorganism such as bacteria and viruses does not influence on the detection of G. intestinalis by microscopic and immunoenzymatic methods in stool samples. Citric acid as an antioxidant added to foods affects the detection of G. intestinalis. Due to the small number of samples used, it is necessary to continue research on the impact of various factors on the detection of protozoa.

Comparison of molecular and microscopic technique for detection of Theileria spp. in carrier cattle

In Iran, theileriosis is normally diagnosed with traditional Giemsa staining method. This is not applicable for identification of the carrier animals. The aim of this study was to compare conventional Giemsa staining method with the PCR technique in the detection of Theileria organisms. In this study, examinations were performed on 150 blood samples from cattle without clinical signs. Sensitivity and specificity of 50 microscopic fields were compared with Theileria specific PCR. The degree of agreement between PCR and microscopic test was determined by Kappa (κ) values with 95 % confidence intervals. PCR showed that 42 samples were Theileria spp. positive, while routine microscopy showed erythrocytes harboring Theileria like structures in 11 blood samples. Examination of 50 microscopic fields showed 57 % sensitivity and 99 % specificity compared to 100 % sensitivity and specificity for PCR. The κ coefficient between PCR and Microscopy (50 fields) techniques indicated no level of agreement. Our results showed that the microscopic examination remains the convenient technique for day-to-day diagnosis of clinical cases in the laboratory but for the detection of carrier animal containing low parasitemia. Therefore, molecular methods such as PCR can be used as a safe method for identifying cattle persistently infected with Theileria spp.

Comparison of Microscopy and PCR-RFLP for detection of Anaplasma marginale in carrier cattle

BACKGROUND AND OBJECTIVES

In Iran, anaplasmosis is normally diagnosed with traditional Giemsa staining method. This is not applicable for identification of the carrier animals. The aim of this study was to compare the detection of Anaplasma marginale in two different numbers of microscopic fields (50 and 100) using conventional Giemsa staining method compared with the PCR-RFLP technique.

MATERIALS AND METHODS

In this study, examinations were performed on 150 blood samples from cattle without clinical signs. Sensitivity and specificity of two microscopic fields (50 and 100 fields) were compared with A. marginale specific PCR-RFLP. The degree of agreement between PCR-RFLP and the two microscopic tests was determined by Kappa (κ) values with 95% confidence intervals.

RESULTS

PCR-RFLP showed that 58 samples were A. marginale, while routine microscopy showed erythrocytes harboring Anaplasma like structures in 16 and 75 blood samples determined in 50 and 100 microscopic fields respectively. Examination of 50 and 100 microscopic fields showed 25.8% and 91.4% sensitivity and 99% and 76.1% specificity compared to 100% sensitivity and specificity by PCR-RFLP. The Kappa coefficient between PCR-RFLP and Microscopy (50 fields) indicated a fair level of agreement (0.29). The Kappa coefficient between PCR-RFLP and Microscopy (100 fields) indicated a good level of agreement (0.64)

CONCLUSION

Our results showed that the microscopic examination remains the convenient technique for day-to-day diagnosis of clinical cases in the laboratory but for the detection of carrier animal with low bacteremia, microscopy with 100 fields is preferable to Microscopy with 50 fields and molecular methods such as PCR-RFLP can be used as a safe method for identifying cattle persistently infected with A. marginale.