By Dr Chandrasekhar Nair
Vector-borne diseases continue to contribute significantly to the global burden of disease and cause epidemics that disrupt health security and cause wider socioeconomic impacts around the world.
Monsoons, additionally, witness increased outbreaks of multiple vector-borne diseases. The favourable conditions during monsoons can support the transmission of multiple diseases such as dengue, chikungunya, and Zika, concurrently. This creates additional challenges for healthcare systems, public health authorities, and communities in effectively managing and controlling these outbreaks.
Hence, implementing a robust surveillance system is crucial to monitor vector-borne diseases and detect outbreaks early. This includes regular collection and analysis of data on disease incidence.
Rapid testing plays a vital role in effective disease management during the rainy season. By promptly identifying cases, healthcare providers can implement timely administration of specific treatments, supportive care, and necessary interventions to prevent severe illness or complications associated with these diseases.
While available rapid antigen and antibody tests for the detection of vector-borne diseases have their advantages, they also have certain limitations or demerits that should be considered such as lower sensitivity, false-negative results, limited window of detection, delayed detection and inability to distinguish current ongoing infection. The performance of rapid these tests can vary depending on the specific test kit and the stage of infection.
The rapid NS1 test is often used as a screening tool, however, it can cross-react with antibodies or other related flaviviruses and can lead to incorrect diagnoses, especially in areas where multiple flaviviruses are co-circulating. The NS1 test may not detect all dengue virus serotypes or strains. Moreover, there can be variations in the NS1 protein among different strains, which may affect the test’s ability to detect certain strains. These limitations should be considered when interpreting the results and determining the appropriate testing strategy for individual cases.
Additionally, there is a possibility of getting infected with both viruses at the same time, which cannot be detected by immunological assays. Co-infection can cause neurological and optical manifestations. This underscores the necessity for accurate diagnostic laboratory tests to distinguish chikungunya infections in the background of actively co-circulating dengue.
PCR test, on the other hand, is highly sensitive and can detect even low levels of the pathogen enabling early detection of infections, including in the pre-symptomatic or asymptomatic stages, when other diagnostic methods may yield negative results. It can differentiate between closely related pathogens or strains enabling detection of multiple pathogens and early identification of co-infections for appropriate treatment and management strategies. Co-infections can complicate the clinical presentation and require tailored therapeutic approaches, making PCR an invaluable tool for accurate diagnosis. Overall, PCR saves time and resources by providing a comprehensive assessment of the disease situation.
While PCR offers numerous advantages, it is important to note that it requires specialised laboratory infrastructure and trained personnel. It may not be as readily available in resource-limited or remote settings compared to other rapid diagnostic tests. However, advancements in technology are making PCR more accessible and affordable, expanding its utility in the diagnosis and management of vector-borne diseases.
PCR technology has evolved to offer rapid and automated platforms, such as point-of-care PCR systems. These systems provide results within a short time frame, typically within hours. Rapid PCR testing allows for prompt diagnosis and timely initiation of appropriate treatment and control measures, which is crucial for managing vector-borne diseases and preventing their further spread.
Overall, point-of-care PCR tests are essential tools for disease outbreaks and surveillance. Their rapid turnaround time, portability, accuracy, and suitability for field deployment contribute to early diagnosis, enhanced surveillance, and informed decision-making during outbreaks. These tests are critical in minimizing the impact of outbreaks, implementing timely control measures, and protecting public health.
(The author is a Director and CTO, Molbio Diagnostics. Views expressed are personal and do not reflect the official position or policy of the FinancialExpress.com.)
