Leptospirosis outbreak in Magnesia, Central Greece linked to catastrophic floods

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CASE REPORT

Hippokratia 2024, 28(3): 129-133

Katsafourou E, Nikolaidou F, Nikolaou E, Gaitanis N, Karakasidis E, Potolidis E
First Internal Medicine Department, General Hospital of Volos, Volos, Greece

Abstract

Background: Leptospirosis, a widespread zoonotic bacterial disease, is transmitted to humans through direct contact with infected animals -primarily rodents- or exposure to contaminated standing water. Its incidence is higher in tropical climates and areas prone to heavy rainfall or flooding. After the severe floods in Magnesia, Central Greece, in the fall of 2023, we observed a significant increase in leptospirosis cases.

Case Description: We present three cases of previously healthy young adults who contracted leptospirosis and required medical attention. These cases highlight the variability in clinical presentations, the challenges of differential diagnosis, and the different treatment approaches used for each patient.

Conclusions: Extreme weather events, such as flooding, are associated with increased incidence of leptospirosis in areas where the disease was uncommon in the past. Early suspicion, comprehensive investigation, and accurate diagnosis are critical to improving patient outcomes. HIPPOKRATIA 2024, 28 (3):129-133. 

Keywords: Leptospirosis, floods, zoonotic disease, Central Greece

Corresponding author: Potolidis Evangelos, MD, Chief of First Internal Medicine Department, Volos General Hospital “Achillopouleio”, 38221, Volos, Magnesia, Greece, tel: +302421351848, e-mail: potol13@gmail.com

Introduction

Leptospirosis is one of the most widespread zoonotic bacterial diseases worldwide, with a higher prevalence in tropical regions, particularly during the monsoon season1. It is estimated that approximately 1,000,000 people become infected each year, resulting in 60,000 deaths. Outbreaks can occur in areas with heavy rainfall or flooding, even if not in the endemic zone2. The pathogenic microorganism responsible for the disease, first described by Weil in 18863, is an aerobic, motile spirochete of the genus Leptospira that forms hooks at each end. Mammals -especially rodents- and their environment (water, soil), when the urine of infected mammals contaminates it, act as the main reservoirs for leptospira organisms2. Transmission occurs through bites from infected animals or when mucous membranes, conjunctivae, or skin lesions come into close contact with contaminated soil or water. For this reason, farmers, people of low socioeconomic status, travelers to endemic areas, and people who frequently engage in water-related activities are at the greatest risk of exposure2,4,5. After infection, the incubation period is usually two to 20 days, and the clinical course can vary from asymptomatic to severe illness with fever, myalgias, headache, jaundice, renal failure, or even death6.

Typically, the symptomatic disease is divided into two categories: anicteric, which is biphasic with an acute and a late phase, and icteric leptospirosis. The latter is also called “Weil’s disease” and is a rather multisystem disease with a mortality rate of 10 %7. The World Health Organization proposed in 1982 the Faine criteria for diagnosing leptospirosis, which were based on clinical and laboratory findings, as well as epidemiological factors8. These criteria were modified to increase their sensitivity in 2004 and are still valuable today9,10. Nowadays, definitive diagnosis is made by laboratory tests, with polymerase chain reaction (PCR) of blood or urine samples having the highest specificity (95 %) and sensitivity (40-60 %)2. Treatment of leptospirosis depends on the severity of the infection and includes supportive care and antibiotics: doxycycline, azithromycin, amoxicillin, and ceftriaxone11,12. In Greece after the catastrophic floods in September 2023, a peak incidence of Leptospirosis was recorded in Magnesia, Central Greece. Here we report three cases of Leptospirosis with varying clinical features.

Case Presentation

First patient

A man in his 20s presented to our hospital’s Emergency Department (ER) with a primary complaint of persistent fever with rigors. Up to three days before his presentation, he was in his usual state of health, and thereafter, he began to have a fever -mainly in the afternoon and evening- along with rigors. A day later, myalgias and arthralgias were added to his symptoms. Additional history revealed no consumption of unpasteurized cheese or raw meat. However, before the onset of the fever, the patient worked in the fields and had close contact with animals during the floods. On examination, the temperature was 38.8 °C, while the rest vital signs were within normal limits. He did not display any respiratory distress but was jaundiced, as indicated by his icteric sclera. During the abdominal examination, he showed mild tenderness in the right lower quadrant with normal percussion and bowel sounds. The rest of the clinical examination was normal. A complete blood count and metabolic panel in the ER showed neutrophilia with thrombocytopenia (white blood count: 11,000, platelets: 114,000), elevated liver enzymes (aspartate transaminase: 352 IU/L, alanine transaminase: 463 IU/L), elevated bilirubin (total: 1.5 mg/dL, direct: 1 mg/dL), and increased high-sensitive C-reactive protein (CRP: 60 IU/L). A chest X-Ray along with an abdominal ultrasound were also performed. The first presented no pathological findings, while the second showed hepatomegaly (diameter 17.5 cm) and a swollen lymph node at the porta hepatitis.

Subsequently, the patient was admitted to the hospital for further investigation. The patient’s presentation of an acute febrile illness with rigors, jaundice, and hepatic involvement, along with the history of exposure to flooded fields, suggested an infectious etiology. Firstly, urine and blood cultures were obtained before initiating antibiotics for potential bacterial infections. Both cultures remained negative for four days. Although the patient denied consumption of unpasteurized dairy or raw meat, we performed a serological test for Brucellosis, which was negative, ruling out this diagnosis. A severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) antigen test was also performed, and a negative result was obtained. Given the presence of hepatic involvement, extensive screening for hepatotropic and other potentially related viruses was conducted. Serological tests for cytomegalovirus, Epstein-Barr virus, herpes simplex virus-1 and -2, varicella-zoster virus, and human immunodeficiency virus were negative. Also, a comprehensive hepatitis panel, including hepatovirus A IgG/IgM, HBsAg, Anti-HBs, Anti-HBc, HBeAg, and hepatitis C virus IgG, yielded negative results. Due to his background as an immigrant from a country with higher tuberculosis rates and his work with livestock, a Mantoux test (negative, 3 mm induration at 72 h) and a leishmaniasis PCR (negative) were conducted. Non-infectious causes such as autoimmune hepatitis, Wilson’s disease, toxic or drug-induced hepatitis, hemolytic-uremic syndrome, and malignancies were also considered. However, these were deemed less likely due to the acute onset of symptoms, lack of supporting clinical or laboratory findings, and the absence of relevant exposures or chronic features typically associated with these conditions.

Due to recent exposure to stagnant water, along with the strong advisory from the National Public Health Agency to have a heightened vigilance for potential Leptospirosis cases, Leptospirosis was highly suspected. A blood sample was sent to the University Hospital of Larisa (UHL) for PCR testing since the necessary diagnostics were unavailable at our facility [there were no serological tests such as Microscopic Agglutination Test-MAT, enzyme-linked immunosorbent assay (ELISA) nor molecular tests such as PCR]. Because of the high probability of Leptospirosis, the patient was given ceftriaxone (2 g once daily) and azithromycin (500 mg once daily) during hospitalization. Azithromycin was included to cover atypical or co-infections that could occur in patients exposed to environmental pathogens during flooding (e.g., respiratory or gastrointestinal infections). In the following days, the test results confirmed leptospirosis, and the patient continued antibiotic treatment with ceftriaxone alone. The fever subsided completely on the second day of hospitalization. Liver enzyme levels returned to near normal on the fourth day of hospitalization [aspartate transaminase (AST): 55 IU/Lt, alanine transaminase (ALT): 60 IU/Lt] and the patient was able to be discharged. Doxycycline 100mg every 12 hours was administered at home until the completion of the antibiotic treatment course (10 days in total).

Second patient

A man in his 20s presented to the ER with a two-week history of persistent fever, now accompanied by abdominal pain, diarrhea, and a cough for the past week. His personal physician had prescribed Amoxicillin-clavulanate four days prior, with no clinical improvement. He had no comorbidities or regular medications. A thorough history revealed recent exposure to standing floodwater during voluntary cleanup operations without protective measures. He was febrile (38 °C), with normal other vital signs and clinical examination revealed epigastric pain, increased bowel sounds, and persisting cough. Chest and abdominal X-rays were unremarkable. Blood tests showed elevated high-sensitivity-CRP (hs-CPR: 67 mg/L). The patient was then admitted for further evaluation, and additional laboratory tests were conducted to investigate possible bacterial and viral infections, following a similar approach to the first patient. All available tests at our hospital were negative, and at the same time, we sent blood and urine samples to UHL for leptospirosis PCR.

Due to the high suspicion of Leptospirosis and increased rates of community-acquired pneumonia in our region during the fall, ceftriaxone 2 g once daily and azithromycin 500 mg once daily were administered. However, during his stay, and while awaiting the results from the UHL, the patient continued to have fever and elevated inflammation markers. For this reason, we further investigated the etiology of the patient’s symptoms, considering both infectious and non-infectious causes. We performed chest, brain, and abdomen computed tomography scans, which helped rule out malignancies and localized infectious diseases affecting the internal organs. Also, a lumbar puncture was performed, and the cerebrospinal fluid (CSF) analysis was normal (the biochemical values for glucose, protein, and the cell count were negative; a meningoencephalitis panel was conducted for a plethora of bacteria and viruses, including dengue virus, which was also negative). Due to the ongoing fever, a suspicion of hemophagocytic disease was considered. However, it was eventually ruled out after normal values of platelets, clotting factors, ferritin and lipids were obtained along with the absence of spleen enlargement. During our differential diagnosis process, the PCR results from UHL confirmed the presence of leptospira infection with a positive urine PCR test, and the patient continued the antibiotic therapy.

However, on the 6th day of hospitalization, the patient developed headaches and chills. Detection of spirochetes in the urine suggested the immune phase of leptospirosis, characterized by seroconversion (IgM antibodies in the blood) and increased urinary excretion as spirochetes localize in the kidneys. We then assessed for related clinical features, including uveitis, central nervous system, and cardiovascular involvement, which were ruled out after ophthalmologic evaluation, repeat CSF analysis and transthoracic echocardiography. Methylprednisone 40 mg once per day was then initiated. In the next couple of days all his symptoms resolved, and he was able to be discharged soon afterwards with doxycycline 100 mg twice daily for four days and additionally methylprednisolone 16 mg per os which was reduced slowly with a tapering course.

Although the patient was hypothesized to be in the immune phase of leptospirosis and showed clinical improvement following corticosteroid treatment, further investigation into potential autoimmune diseases was not conducted due to our hospital’s unavailability of specialized tests and expertise. Consequently, we arranged for the patient to visit the rheumatology clinic at UHL as an outpatient to undergo a comprehensive autoimmune panel, including testing for rheumatoid factor and anti-cyclic citrullinated peptide (anti-CCP) antibodies. Despite our suggestion to visit a rheumatologist ten days after the discharge, the patient presented again in the ER with complaints of high fever. He was transported to the nearby UHL, where he was admitted to the rheumatology ward. After performing the appropriate laboratory tests, he was diagnosed with systemic juvenile rheumatoid arthritis (JRA) and he was prescribed adalimumab on a weekly basis.

Third patient

A woman in her 20s presented in the ER with a main complaint of persisting fever for ten days and fatigue. On arrival, her temperature was 37.8 °C, while the rest of her vital signs were normal. A comprehensive medical and social history was obtained, revealing a diagnosis of celiac disease and recent exposure to flood waters. She showed mild tenderness to the left lower quadrant during clinical examination with normal bowel sounds, and the rest of the examination was normal. A detailed blood panel was collected, which showed an elevation in hepatic enzymes (AST: 77 IU/lt, ALT: 140 IU/lt, γGT: 209 IU/lt) and elevated hs-CRP (38.8 mg/lt). Furthermore, an abdominal ultrasound was conducted, and it showed elevated echogenicity of the liver parenchyma.

The patient was admitted to the hospital, where we followed the same investigative procedure as the other patient to determine the cause of the symptoms. Among the laboratory tests available at our hospital, all results were negative except for a hepatitis virus panel that revealed positivity for anti-HBs and anti-HBc IgM, indicating a recent hepatitis B virus (HBV) infection (less than six months Despite testing positive for hepatitis B, there was also a high possibility of leptospira infection and a blood and urine sample were sent for PCR to the laboratory at UHL. PCR blood test came back positive for leptospira. Due to her good clinical condition we decided to treat her as an outpatient with doxycycline 100 mg twice daily for seven days. Four days after her first visit, we performed a follow-up at our outpatient clinic: the symptoms had completely subsided, and the hepatic enzymes along with the hs-CRP showed a reduction [AST: 63 IU/lt, ALT: 115 IU/lt, gamma-glutamyltransferase (γGT): 187 IU/lt]. She continued the administered antibiotics until completion.

In response to the initial positive results for Hepatitis B, we arranged a visit to the hepatologic department at UHL. The patient initially underwent a comprehensive laboratory panel including ANA, ASMA, Anti-LKM-1, and SLA antibodies, ruling out autoimmune hepatitis. She was then advised to repeat the laboratory exams for HBV after six months. Following this guidance, she repeated the HBV antibody tests six months after the initial positive result. At that time, only the anti-HB antigen was positive. The previous anti-HBc IgM positivity observed in the fall of 2023 was determined to be a result of cross-reactivity with leptospirosis antibodies. 

Discussion

Leptospira is a bacterium with features of both gram-negative and gram-positive bacteria: an outer lipopolysaccharide membrane and an inner peptidoglycan layer. In mammals, particularly rodents, a primary reservoir resides in renal tubules and is excreted in urine13. Furthermore, it can survive for weeks in mud, soil, and water. Although transmission to humans can happen through abraded skin, it has not yet been clarified if transmission can occur through intact skin. Transmission between humans is infrequent and can occur through sexual intercourse or breastfeeding14. Those infected with Leptospira can shed the bacteria through urine for up to two months. People at higher risk of contracting the disease include farmers, livestock handlers, veterinarians, water activity enthusiasts, individuals living in poor sanitation conditions with low socioeconomic status, and travelers to endemic areas.

The European Center for Disease Prevention and Control (ECDC) estimated that Greece reported 20-25 cases of leptospirosis annually until 20222. However, in September 2023, flash floods caused by Storm Daniel and Storm Elias in Thessaly, Central Greece, led to a significant increase in leptospirosis cases in the region. Notably, even before the second storm (Elias), 42 cases had already been reported nationwide15. Historically, outbreaks of leptospirosis have been documented in the literature with as few as three recorded cases. While the ECDC’s weekly report in September classified the rise in cases as a cluster, the substantial increase following the floods in Magnesia may warrant classifying this event as an outbreak in the next ECDC annual report. We recorded six leptospirosis cases in the General Hospital of Volos from September to December 2023. Here, we present three of these cases.

Leptospirosis symptoms range from mild (fever, headache, myalgia, nausea, vomiting, jaundice) to severe (kidney or liver failure). The infection has two forms: anicteric (more common and less severe) and icteric (severe and potentially fatal)16,17. Anicteric leptospirosis typically has two phases: an acute phase (up to nine days, with bacteremia) and an immune phase (bacteria present in urine but not blood; antibodies for leptospira are detected in the blood). The acute phase is characterized by non-specific symptoms like fever with rigors, myalgia, headache, and laboratory findings like elevated erythrocyte sedimentation rate, leukocytosis, an elevation in liver enzymes, creatinine, and urea, while the immune phase is characterized by specific immune-mediated symptoms with aseptic meningitis and uveitis being the most prominent ones. The icteric form, also known as Weil’s disease, is the more severe (potentially fatal) and multiorgan form of the infection with jaundice, fever, and renal failure18. More severe but less common complications are pulmonary hemorrhage, disseminated intravascular coagulation, myocarditis, and acute respiratory distress syndrome (ARDS)7,19,20. Elevation in bilirubin and creatinine levels, along with electrocardiographic abnormalities, are some of the laboratory findings during this form.

Leptospirosis diagnosis can be challenging due to symptom overlap with other illnesses and reliance on specific tests21. Physicians should also consider potential false positives from cross-reactivity, as seen in the third reported patient with HBV. In our third case, despite other lab results, we pursued leptospira testing based on strong clinical suspicion. Additionally, non-infectious causes of the symptoms, such as autoimmune diseases should also be ruled out. Notably, a study in Taiwan has shown a connection between leptospirosis and sudden acquired retinal degeneration syndrome (SARDs), suggesting that leptospirosis may trigger conditions like juvenile idiopathic arthritis (JRA) by affecting the immune system, particularly through T helper type 17 pathways and cytokine release22. In the reported cases, the second patient showed temporary improvement with antibiotics but continued to experience symptoms, including fever. We considered the possibility of either the immune phase of leptospirosis or the onset of an autoimmune disease following infection. The patient was ultimately diagnosed with JRA. While it was difficult to determine which symptoms were attributable to the infection versus the autoimmune disease, his initial improvement with antibiotics suggests leptospirosis was the primary cause of his symptoms at admission.

Diagnosis of leptospira is confirmed through molecular (PCR in blood samples, which is positive during the bacteremic phase of the disease and PCR in urine samples, especially after the first week of infection) or serologic tests (IgG and IgM in blood samples; the antibodies become detectable in blood after the first week). The specificity for the molecular tests is 70-93 % and the sensitivity 100 %, while follow-up serologic tests 7-14 days after the initial serologic tests are mandatory for confirmation of the diagnosis23,24 due to the lower specificity and sensitivity. Unfortunately, no serology tests were performed in our three cases due to their unavailability at our hospital and UHL. Blood, urine, or blood culture can also be used, but they have a suboptimal sensitivity in comparison to PCR and serologic tests24,25.

As far as treatment is concerned, most cases are self-limited and do not require antimicrobial therapy; for mild cases, which are treated as outpatients, doxycycline 100 mg twice per day for seven days or azithromycin 500 mg once per day is advised. For pregnant women, we favor treatment with azithromycin or amoxicillin (500 mg three times per day for seven days) due to severe tetracycline adverse effects on the fetus. In severe infection that demands hospitalization, the patient is treated with doxycycline 100 mg twice per day, azithromycin 500 mg once per day, cefotaxime (100-150 mg/kg in three doses), or ceftriaxone 2g once per day for seven days. Support care with renal replacement therapy, infusion of blood products, and ventilatory support when required has been shown to improve the course of the infection immensely alongside antimicrobial therapy26.

Intravenous corticosteroid therapy has been given in patients with inappropriate immune response (e.g., pulmonary hemorrhage) to suppress excess inflammation27. The similarity between the cytokine storm in the immune phase of Leptospirosis and that in coronavirus disease 2019 (COVID-19) patients with disease progression and ARDS, further supports the use of corticosteroids in leptospirosis, similar to their established role in COVID-19 management28. Nevertheless, the evidence is insufficient for routine use of corticosteroids, and clinicians should individualize their decisions.

Leptospirosis is an increasingly significant global health threat, exacerbated by climate change, leading to more frequent and intense extreme weather events, such as floods and heavy rainfall. These conditions create environments conducive to the spread of leptospira bacteria (the most recently affected region was Spain). For clinicians, it is crucial to recognize the growing risk of leptospirosis, especially in areas impacted by environmental changes. Timely suspicion and diagnosis of leptospirosis can significantly impact patient outcomes, as the disease can present with nonspecific symptoms that may mimic other infectious conditions.

Conflict of interest

All authors state that they have not any conflict of interest or financial support.

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