Molecular Diagnosis of Visceral Leishmaniasis

Abstract

Visceral leishmaniasis (VL), a deadly parasitic disease, is a major public health concern globally. Countries affected by VL have signed the London Declaration on Neglected Tropical Diseases and committed to eliminate VL as a public health problem by 2020. To achieve and sustain VL elimination, it will become progressively important not to miss any remaining cases in the community who can maintain transmission. This requires accurate identification of symptomatic and asymptomatic carriers using highly sensitive diagnostic tools at the primary health service setting. The rK39 rapid diagnostic test (RDT) is the most widely used tool and with its good sensitivity and specificity is the first choice for decentralized diagnosis of VL in endemic areas. However, this test cannot discriminate between current, subclinical, or past infections and is useless for diagnosis of relapses and as a prognostic (cure) test. Importantly, as the goal of elimination of VL as a public health problem is approaching, the number of people susceptible to infection will increase. Therefore, correct diagnosis using a highly sensitive diagnostic test is crucial for applying appropriate treatment and management of cases. Recent advances in molecular techniques have improved Leishmania detection and quantification, and therefore this technology has become increasingly relevant due to its possible application in a variety of clinical sample types. Most importantly, given current problems in identifying asymptomatic individuals because of poor correlation between the main methods of detection, molecular tests are valuable for VL elimination programs, especially to monitor changes in burden of infection in specific communities. This review provides a comprehensive overview of the available VL diagnostics and discusses the usefulness of molecular methods in the diagnosis, quantification, and species differentiation as well as their clinical applications.

A case of visceral leishmaniasis found by left oblique hernia: A case report

“…Moreover, this method lacks the ability to distinguish between active or previous infections (21). Recent advances in molecular biology techniques and second-generation sequencing can improve the current method and increase the diagnostic value and dynamic monitoring of VL diseases (1).…”

“…According to the World Health Organization, approximately 200,000-400,000 new cases of visceral leishmaniasis (VL) occur every year in the world, 90% of which are noted in Southeast Asia, Latin America and East Africa (1). Based on the continuous emergence of new VL cases, the Indian subcontinent, Nepal, and Bangladesh were affected by VL and had to postpone the plan to eliminate VL from 2015 until 2020 (2).…”

Leishmaniasis in Transplant Candidates and Recipients: Diagnosis and Management

“…However, asymptomatically infected individuals may have positive PCR test without any further disease development; thus, a positive PCR result does not always indicate disease [12]. In this regard, quantitative PCR may represent an important tool in early diagnosis and may indicate relapse [50].…”

Isolation and characterisation of Leishmania donovani protein antigens from urine of visceral leishmaniasis patients

“…Conventional serology, which detects anti- Leishmania IgG, has several drawbacks: it is ineffective at confirming cure or relapse because it can remain positive for many years after successful treatment [ 2 – 6 ]; it is also less reliable in HIV co-infected cases where a negative result does not rule out leishmaniasis [ 7 ]. Molecular assays are sometimes applied, and may gain increased importance during VL elimination, however, non-invasive antigen detection would complement this as a diagnostic tool [ 8 ].…”