Why do Doctors Miss the Diagnosis of Leptospiral Uveitis? Emergence of New Serovars and Challenges in Diagnosis.

PURPOSE: Leptospirosis is an endemic disease in India and uveitis is its late complication. Several Indian reports showed diversity of serovars, changing patterns and existence of new serovars. Failure to add new serovars in testing panel result in increased false-negativity in serology. AIM: To analyse seroprevalence, changing patterns and to discuss the resulting challenges in diagnosis. METHODS: In this retrospective study covering the period from 1994 to 2020, we analysed data from laboratory records of patients diagnosed with leptospiral uveitis in South India. Microscopic agglutination Test (MAT) and/or Enzyme-Linked Immunosorbent Assay (ELISA) were performed on clinically diagnosed leptospiral uveitis cases from our hospital, as well as on systemic leptospirosis patients from government and private hospitals. RESULTS: Out of a total of 87 216 new uveitis cases with varying causes over 27 years, 3,658 (4.1%) were clinically diagnosed as leptospiral uveitis. Among them, 1,268 (34.7%) patients were seropositive. In 1994, 92% of clinically diagnosed leptospirosis patients were seropositive in the MAT performed at the Centers for Disease Control and Prevention in Atlanta. However, the positivity rate gradually declined to 35% over the years. The predominant serovars identified were L. autumnalis, L. icterohaemorrhagiae, and L. australis. There were notable variations in the distribution of serovars over the years. CONCLUSIONS: The data suggest a declining sensitivity of MAT and ELISA, possibly due to the emergence of new serovars. Customizing the panel based on local isolates could enhance the performance of MAT. Critical need is the addition of advanced molecular techniques to improve the diagnosis.

Leptospiral uveitis- "Transition 'from epidemic to endemic form" difficulties in laboratory confirmations.

Purpose: Leptospirosis is a waterborne zoonotic disease that primarily causes systemic illness, followed by uveitis. After heavy flooding in Madurai district, an epidemic outbreak of systemic and ocular leptospirosis occurred in 1994. Our data shows a transition to endemicity after each epidemic. Aim: The aim of this study is to report the clinical signs, epidemic outbreaks, and persistent endemicity of leptospiral uveitis, as well as the diagnostic dilemmas associated with it. Methods: A retrospective analysis of clinical signs was conducted using medical records of leptospiral uveitis patients over a period of 27 years (1994-2020) in a tertiary care eye hospital. The clinical workup of uveitis included a detailed clinical history, systemic, and ophthalmic examination. Microagglutination tests (MATs) was done at the Centers for Disease Control and Prevention (CDC) in Atlanta and later in our regional laboratory. Serum samples were collected from human systemic leptospirosis cases and a small group of animals in and around Madurai. Results: The first epidemic outbreak resulted in 200 seropositive patients. Subsequent epidemic outbreaks occurred in 1997, 1998, 2001, 2005, and 2012, with Madurai experiencing multiple outbreaks. However, the disease remained endemic, with 25-50 patients being observed per year in between the peaks. Ocular examination revealed acute non-granulomatous uveitis (94.9%), pan uveitis (59.8%), vitreous inflammatory reaction (55.4%), retinal vasculitis (29.5%), disc hyperemia (20.9%), and hypopyon. (16.2%). New serovars emerged every year, resulting in decreased sensitivity of the MAT. Over time, the MAT started to miss diagnoses. Conclusion: The persistent endemicity of leptospiral uveitis emphasizes the need for accessible diagnostic tests. The low performance of the MAT can be attributable to the use of an older panel. The incorporation of new isolates in the MAT by a national laboratory will improve the accuracy of diagnosis.