Tribhuvan University Journal of Microbiology (TUJM) Volume 10(1), 2023

 

Editorial

Advanced Molecular Techniques and Diagnosis of Febrile Illness

 

The application of multiplex real-time (Reverse Transcriptase - RT) polymerase chain reaction (PCR) in routine diagnosis of infectious diseases is unavoidable. In addition, the technique urgently might be an alternative tool in the diagnosis of febrile illnesses caused by many different kinds of etiologies including bacteria, viruses, and parasites. In Nepal, arboviral infections mainly dengue and chikungunya, scrub typhus, and leptospirosis are considered as major emerging infections in the last two decades. In addition, these infections are the most predominant neglected tropical diseases in tropical and subtropical regions where more than 51% of the total population in Nepal is living. A few of these infections are responsible for chronic infection causing a high morbidity rate. A study reported up to 40% of acute chikungunya infections may lead to chronic infections. Similarly, secondary infections can be more severe among flaviviruses such as Dengue and Zika due to antibody-dependent enhancement.  Unlike the diagnosis of other neglected tropical diseases, the differential diagnosis of arboviral infections is quite difficult as they all present similar clinical features, especially in Dengue Chikungunya and Zika viral infections.  However, few studies showed a significant difference in clinical manifestations in specific viral infections as well. Some clinical features are significantly associated with bacterial and viral infections. High-grade fevers with longer mean duration of fever, severe musculoskeletal pain, central nervous system (CNS) related symptoms (such as altered mentation, confusion, and loss of consciousness), and elevated liver enzymes such as aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are highly associated with viral infections as compared to bacterial infections Finding such clinical manifestations may be helpful in the differential diagnosis of febrile illnesses as the point of care for future aspects. The other means of diagnosis commonly used in hospital settings of Nepal are serological methods including routinely used rapid diagnostic tests (RDTs) and Enzyme-Linked Immunosorbent Assay (ELISA). However, these methods have a few drawbacks including cross-reactivity, low sensitivity, and specificity making misdiagnosis of infections. Moreover, these methods are not applicable to early diagnosis of infections. An alternative to serological methods is molecular methods which are currently not available for diagnostic purposes in most hospitals and health care centers. Although the conventional PCR method has high sensitivity and specificity, it may take a longer time and detect only a particular pathogen at a time. The molecular method mainly real-time (RT) PCR has many advantages over other conventional methods because of which the applications of this technique for the diagnosis of infections or illnesses can’t be avoided. The techniques have already been introduced in the diagnosis of respiratory viral pathogens to diagnose flu-like syndromes in very few hospital settings. However, many tertiary care hospitals in Nepal have not been facilitated to use this technique in routine diagnosis. In addition, febrile illnesses in tropical and subtropical regions are the most undiagnosed illnesses. As a consequence, a number of patients have been suffering from chronic bacterial and viral infections. Real-time (RT) PCR is the only ultimate tool in the diagnosis of such illnesses.   The method has not only higher sensitivity (> 95%) and specificity (100%) but also detects the possible pathogens as early as the first day of onset of illness. Because of good reproducibility, sensitivity, and specificity, this method is considered a gold standard method for the detection of RNA viruses in clinical specimens. In addition, the multiplex real-time (RT) PCR detects multiple pathogens in a single run making it more economical and less time-consuming in the hospital settings of low and middle-income countries. It seems to be affordable to common people as well.  While talking about the current situation in Nepal, several tertiary care hospitals have upgraded to real-time PCR for diagnosis of COVID-19 during the pandemic. Hence, a similar facility can be extended to detect other pathogens in neglected tropical diseases and febrile illnesses in routine diagnosis.

 

 

Komal Raj Rijal, Editor in Chief

Upendra Thapa Shrestha, Associate Editor

DOI: https://doi.org/10.3126/tujm.v10i1.60644