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.

Application of PCR for Specific Diagnosis of Leptospirosis in Humans in Ukraine

Leptospirosis remains one of the most widespread zoonotic diseases in the world and Ukraine, in particular. Ukrainian clinicians have been faced with early detection of the disease due to the availability of only a serological method for routine diagnostics in Ukraine, namely the microscopic agglutination test (MAT). This paper demonstrates the first results of the complex application of MAT and polymerase chain reaction (PCR) for routine verification of leptospirosis, which were first applied simultaneously in Lviv Oblast of Ukraine in 2016. We examined the sera of 150 patients clinically suspected of leptospirosis, 31 of whom were treated at the Lviv Oblast Clinical Hospital for Infectious Diseases (LOCHID). The application of PCR during the first seven days of the disease allowed increasing the share of confirmed leptospirosis cases by 16,1% in patients that were treated in LOCHID during 2016-2017.

[Diagnostic procedure after abortions in sows after simultaneous infection with leptospira and chlamydia]

INTRODUCTION

In a farrowing farm 2 first parity sows aborted on day 95 and day 110 of gestation due to an infection with leptospira and chlamydia. The double infection was diagnosed by PCR examination of abortion material. Serum samples of both sows and additional 8 sows taken three weeks after abortions were sent to two different labs for serological examination for antibodies against leptospira and chlamydia using a microagglutination test and a complement fixation test, respectively. In both labs the tests for antibodies against chlamydia were negative. Titers against diverse leptospira serovars varied between both labs and were low, so that they were not indicative for the involvement of the two pathogens regarding abortion. This case report indicates the diagnostic difficulties of direct and indirect detection methods for leptospira and chlamydia to assess the impact of these pathogens on observed reproductive failure.

Leptospirosis in Ukraine (Lviv Oblast): Clinical and Epidemiological Features

The article describes the results of a retrospective analysis of medical records of 395 patients with a clinical diagnosis of leptospirosis treated at the Lviv Oblast Infectious Disease Clinical Hospital (Ukraine) between 2002 and 2016. The main risk factors for leptospirosis were contact with rodents or their excrements (26.84%) and bathing in ponds, small lakes, and reservoirs (10.63%). Among 276 patients in whom the anti-leptospira antibodies were detected by the microscopic agglutination test (MAT), the most common serotypes were Leptospira icterohaemorrhagiae (33.33%) and Leptospira grippotyphosa (25.0%). The mortality rate was significantly higher in patients where leptospirosis diagnosis was established based on clinical symptoms without confirmation by MAT (15.13% vs. 5.43%, p < 0.01).

Determination of O:4 antigen-antibody affinity level in O:5 antigen positive and negative variants of Salmonella enterica serovar Typhimurium

Salmonella enterica serovar Typhimurium (S. Typhimurium) has two serological variants: one that expresses the O:5 antigen (1,4,5,12:i:1,2) and one that lacks O:5 antigen (1,4,12:i:1,2). For serotyping, S. Typhimurium is agglutinated by diagnostic O:4 antigen serum. This study was carried out to compare the antigen-antibody affinity of O:4 antigen in S. Typhimurium χ3306 O:5-positive and S. Typhimurium χ3306 O:5-negative strains. The affinity of O:4 antigen with O:4 antigen serum was found to be stronger in the O:5-negative strains compared to O:5-positive strains. Next, we investigated the antigen-antibody affinity of O:4 antigen with O:4 antigen serum in field strains of S. Typhimurium, which showed the same tendency in affinity as seen with S. Typhimurium χ3306 O:5-positive and negative strains. This study suggests that the presence or absence of O:5 antigen causes differences in O:4 agglutination reactions with different field strains of S. Typhimurium.

ECO-EPIZOOTIOLOGIC STUDY OF FRANCISELLA TULARENSIS, THE AGENT OF TULAREMIA, IN QUÉBEC WILDLIFE

In Canada, Francisella tularensis , the zoonotic bacterial agent of tularemia, affects mostly snowshoe hares ( Lepus americanus ), muskrats ( Ondatra zibethicus ), and beavers ( Castor canadensis ). Despite numerous studies, the ecologic cycle and natural reservoirs of F. tularensis are not clearly defined. We conducted a cross-sectional study to estimate the prevalence of F. tularensis in snowshoe hares, muskrats, and coyotes ( Canis latrans ) in four regions of Québec, Canada, and to describe the risk of infection in relation to host and environmental characteristics at three spatial scales. Between October 2012 and April 2013, trappers captured 345 snowshoe hares, 411 muskrats, and 385 coyotes. Blood samples were tested by microagglutination tests, and DNA extracts of liver, kidney, lung, and spleen of snowshoe hares and muskrats were tested by real-time PCR to detect past and active infection to F. tularensis , respectively. Individual host characteristics, including body condition, age, and sex, were evaluated as risk factors of infection, along with ecologic characteristics of the location of capture extracted from geographic databases. Prevalences of antibody to F. tularensis and 95% confidence intervals were 2.9% (1.4-5.1%) in coyotes, 0.6% (0.1-2.1%) in hares, and 0% (0.0-0.9%) in muskrats. Francisella tularensis DNA was not detected by real-time PCR in the pools of four organs from muskrats and hares, but F. tularensis type AI was detected during testing of the individual organs of two antibody-positive hares. Exact logistic regression analyses showed that age was a significant predictor of antibody detection in coyotes, as were the proportion of forest and the proportion of area considered as suitable habitat for hares in the environment around the location of capture of the coyotes. Our results suggest a terrestrial cycle of F. tularensis in the regions studied.

Leptospirosis in Chonbuk Province of Korea in 1987

Leptospirosis is a zoonosis with protean clinical manifestations. Its diagnosis requires a high index of suspicion and is confirmed by isolation of the organism or, more commonly, by serologic tests. In the fall of 1987, after severe flooding, we saw 93 patients with leptospirosis, confirmed by a microagglutination test. Thirteen percent of the patients had no clinical or laboratory findings except fever and headache, but the rest had mild to severe manifestations. Jaundice, renal failure, and aseptic meningitis were not common, but pulmonary symptoms, when present, were striking. The mortality rate was 5%. The main cause of death was asphyxiation due to massive hemoptysis from pulmonary hemorrhage and acute respiratory failure.