Prevalence Of Dengue Virus Serotypes In Blood Donors In Saudi Arabia

Methods

Question:

Discuss about the Dengue Virus Serotypes in Asymptomatic Blood Donors.

According to the reports of World Health organization (2017), dengue has become one of the severe diseases in recent decades and most of the Asian and Latin American countries are suffering from its severity. This is a viral infection originated through mosquitoes and the virus is carried by mainly Aedes aegypti and Aedes albopictus (World Health Organization, 2017). Recently the American Association of Blood Banks and Center of Disease control and Prevention has recommended to screen for the DENV serotypes while blood transfusion, as the rate of diffusion of dengue virus through blood donations has been reported in several studies (Walsh, 2016)

DENV serotype screening has been suggested by the American Association of Blood Bank and Center for Disease Control and Prevention as two Brazilian cities Recife and Rio de Janeiro reported transfusion of RNA positive blood units to 35 recipients, within which 6 developed the disease, however the KSA health authority still do not recommend such screening in western epidemic region of KSA (Levy, 2016). There are two methods to identify DENV serotypes in blood samples, by seizing the non-structural viral protein as well as by conducting RT-PCR. The researcher used an IVD TaqMan multiplex assay to screen the DENV RNA and connected that with the DENV IgG and IgM. In this cross sectional study, the western epidemic province was selected for the study and after obtaining ethical sanction from the Faculty of Applied Medical Sciences Ethics Committee and consent from the 910 participants ranging from 25 to 55 years, blood samples were collected from the blood bank of Hira general hospital and the regional laboratory of holy Makkah between march 2015 to august 2016 (Ashshi, 2017). These participants were declared eligible as per the regulations of KSA ministry of health and after centrifugation of 10 ml sample, 500 aliquot samples were stored in -80 degree Celsius for further PCR and ELISA tests.

For the ELISA detection, the researcher used certified kits for the detection of Igg and IgM against the DENV serotype in the blood sample of the participants. Depending on the ratio of IgG and IgM found in the blood, the donors were denoted primary source or secondary source of infection. Further for the detection of DENV serotype, Fast Track Diagnosis Dengue differentiation kit was used for the TaqMan RT-PCR process and the participants were divided in 6 categories according to the DENV serological results (Ashshi, 2017). The results were statistically analysed using SPSS (V 16) and the complete rate of noticing anti-dengue antibodies was 5.5% for IgM and 39% for IgG. Further as per the ratio of IgG and IgM, the overall rate of prevalence was found to 2.3% for secondary infection and 3.2% for primary infection. While the multiplex PCR assay was able to identify the serotype 2 in maximum of the 910 participants and DENV-4 serotype was found in more than 38 percent of the participants. Therefore, the study was successful to identify serotype 4 in the epidemic region of KSA, and showed that the prevalence of serotype 4 was almost similar to the serotype 2 (Ashshi, 2017). The research was successfully able to demonstrate that blood transfusion is one of the prime way of transmission of dengue as 5.5% prevalence of dengue was detected through PCR. This study however, was proven to be progressive as it was able to detect serotype 4 in the western KSA region. Further, it should also be noted from the research that serotype 4 was identified in the participants, who were positive to IgM antibodies in the ELISA test (Ashshi, 2017).  

ELISA Detection and Analysis

While discussing the results, it should be mentioned that according to the reports of WHO, last few decades witnessed the immigration of 10 million of migrant independent workers especially from Pakistan and India, where the DENV-4 is widespread (UN DESA, 2017). Further, due to the increase in tourism sector, visitors from countries where DENV serotype 1 and 3 is prevalent has visited KSA, increasing the occurrence of those serotypes in the region. Therefore, the two main findings from this research was finding all four serotype in the eligible donors determines the endemic nature of dengue and further 56% of secondary donors within the participants determined that transfusion of dengue through the blood of eligible donors is a major concern and the KSA healthcare authorities should focus on the issue particularly in the endemic region of the country (Ashshi, 2017).

(Fig. 1 determines the prevalence of IgM and IgG among all the 4 serotypes of DENV, Ashshi, 2017)

However, in spite of the success regarding establishment of DENV-4 serotype in the blood transfusion of KSA, several shortcomings were inherited within the research analysis. According to Meyers, Gamst & Guarino (2016), to establish any research finding, it is important for the group of researcher to conduct confirmatory tests regarding the process. The research of Ashshi (2017), was able to find the serotype 4 in the blood serum of eligible donors however, for the confirmation of the statement, they did not carried out other diagnostic techniques such as NSI or viral isolation. Further, the major limitation of the study was inability to identify the viral load in the blood, which would help to recognize that those blood samples were able to develop dengue with serotype 4 or not (Furtado et al., 2012). Therefore, the selection of PCR kit for the detection of serotype 4 was a limitation for the study. Similarly, the usage of ELISA for the qualitative detection of IgM and IgG using the Panbio,Brisbane, QLD, Australia Kit was one of the major limitations. The primary reason behind it was the presence of heterophilic antibodies in the provided antibody of the kit that interferes with the immunoassay. According to Panbio (2018), these are antibodies raised in animal samples that lead to cross react with reagent antibodies added in the ELISA assay, and creates a false positive result. Further the serological cross reactivity is a common phenomenon that misleads the research by detecting the presence of DENV antigens within the assay. Therefore, accurate results are not produced. On the other hand, through this research, the researchers determined that current measures regarding the inhibition of dengue is not appropriate and a selected section of KSA should be monitored to control the blood transfusion of the disease. However, according to Schlenke (2016), the modern technique and pathogen inactivation technologies that has been implemented currently in the process, helps to limit the blood transfusion of diseases and has sifted the paradigm towards the manufacturing of safe and disease free blood. Hence, the KSA government should enhance its pathogen inactivation technologies instead of wasting its resources for continuous monitoring of blood donation events (Schlenke, 2016). Therefore, while critically analyzing the research article, it should be mentioned that more such researches should be conducted in the KSA endemic region to understand the rate of disease occurrence and the frequency of infection using more than one research method so that the result can be established for further disease management process (Meyers, Gamst & Guarino, 2016).

Results

Conclusion

This research was targeted to identify dengue serotypes in the blood donated by the eligible donors of endemic region of KSA for dengue. As the disease was asymptomatic and no previous research present to identify DENV 4 in KSA, this research was of huge importance for the healthcare sector of KSA. Due to increased amount of travelers, and the home of more than 10 million independent workers from India and Pakistan where the serotype 4 is prevalent, KSA eventually become endemic to dengue. Further, by identifying the serotype 4 in the blood samples of donors, the research established the fact that current measures regarding inhibition of dengue is not sufficient and screening of blood donations should be screened in the prevalent region of KSA to prevent the transfusion of dengue in the province.

References

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