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PubMed This is a summary of 14 peer-reviewed journal articles Updated
Infectious Disease

Recognizing the Two Phases of Leptospirosis

At a Glance

Leptospirosis is a biphasic illness, meaning it has two stages. The first phase causes flu-like symptoms and severe muscle pain. After a brief period of feeling better, the second phase begins and can lead to severe organ complications like Weil's disease or lung hemorrhage.

Leptospirosis is often described as a biphasic illness, meaning it typically occurs in two distinct stages [1]. Understanding these phases can help you make sense of why you might feel slightly better for a short time before new, and sometimes more intense, symptoms appear.

Phase 1: The Septicemic Phase

This first stage, also called the leptospiremic phase, usually lasts between 3 and 7 days [1]. During this time, the Leptospira bacteria are actively circulating in your bloodstream [2].

Common symptoms in this stage include:

  • Sudden high fever and chills [1].
  • Intense myalgia (severe muscle pain), often focused in the calves and lower back [1].
  • Severe headache, usually behind the eyes [1].
  • Gastrointestinal issues, such as nausea, vomiting, or diarrhea, which can lead to severe dehydration [1].
  • Conjunctival suffusion: A classic sign where the whites of the eyes become very red, but without any pus or discharge [3][4].

The “Brief Reprieve”

As the first phase ends, your fever may drop, and you might feel as though you are recovering. This “lull” usually lasts only a day or two before the second phase begins [1].

Phase 2: The Immune Phase

In the second stage, the bacteria have moved out of your blood and into your organs, such as your kidneys and liver [2]. Your body begins producing antibodies, and the symptoms you feel now are often caused by your own immune system’s intense response to the infection [1]. This phase can last from several days to weeks. You may experience:

  • Aseptic meningitis: Inflammation of the lining of the brain, causing a stiff neck and severe headache [5].
  • Uveitis: Inflammation inside the eye [6].
  • Organ-specific symptoms, such as changes in urination or abdominal pain [2].

Severe Forms of Leptospirosis

While many cases are mild, some people develop severe complications that require intensive medical care.

Weil’s Disease

This is the most well-known severe form of leptospirosis. It is defined by a specific “triad” of symptoms [7]:

  1. Jaundice: Yellowing of the skin and eyes due to liver involvement [7][8].
  2. Acute Kidney Injury (AKI): A sudden drop in kidney function, often marked by decreased urine output [7][9].
  3. Hemorrhage: Internal or external bleeding, which may appear as small red spots on the skin (petechiae) or bleeding from the nose or gums [10][11].

Severe Pulmonary Hemorrhage Syndrome (SPHS)

This is a life-threatening complication where the bacteria cause bleeding in the lungs [12]. It often starts with a cough and shortness of breath, which can rapidly progress to hemoptysis (coughing up blood) and respiratory failure [12][8][13]. Because this can happen very quickly, it requires immediate hospital monitoring [12].

Distinguishing the “Look-Alikes”

Because it starts with a high fever and body aches, leptospirosis is often mistaken for other tropical diseases like Dengue or Malaria [3][14]. However, severe calf pain and redness in the eyes (suffusion) without pus are strong clinical clues that point specifically to leptospirosis rather than a mosquito-borne illness [3][4].

Common questions in this guide

What are the two phases of leptospirosis?
Leptospirosis typically occurs in two stages: the septicemic phase, where bacteria circulate in the blood, and the immune phase, where the body's immune response causes symptoms in specific organs like the liver and kidneys.
Why did my fever go away and then come back?
This temporary recovery is common and marks the transition between the two phases of the illness. After the initial infection, you may feel better for a day or two before the immune phase begins and your symptoms return.
What does conjunctival suffusion mean?
Conjunctival suffusion is a classic sign of leptospirosis where the whites of the eyes become severely red without any pus or discharge. This specific symptom helps doctors distinguish leptospirosis from other tropical diseases.
What is Weil's disease?
Weil's disease is the most well-known severe form of leptospirosis. It is characterized by a specific combination of three symptoms: jaundice (yellowing of the skin and eyes), acute kidney injury, and internal or external bleeding.
What are the signs of Severe Pulmonary Hemorrhage Syndrome (SPHS)?
SPHS is a life-threatening complication where the bacteria cause bleeding in the lungs. It typically starts with a cough and shortness of breath, which can quickly progress to coughing up blood and requires immediate hospital care.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Am I currently in the septicemic phase or the immune phase of the infection?
  2. 2.Given my symptoms, should we be monitoring my kidney function and bilirubin levels daily?
  3. 3.Is 'conjunctival suffusion' present in my eyes, and does that help confirm the diagnosis?
  4. 4.If my fever goes away and then returns, does that mean I am entering the immune phase?
  5. 5.What are the specific signs that would indicate I might be developing Severe Pulmonary Hemorrhage Syndrome (SPHS)?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (14)
  1. 1

    Deeply jaundiced: Not so surgical after all.

    du Plessis WP, Lahri S, Somers K, Lovelock T

    Southern African journal of infectious diseases 2023; (38(1)):559 doi:10.4102/sajid.v38i1.559.

    PMID: 38058661
  2. 2

    Evaluation of Serological Tests for Different Disease Stages of Leptospirosis Infection in Humans.

    Rodríguez-Rodriguez VC, Castro AM, Soto-Florez R, et al.

    Tropical medicine and infectious disease 2024; (9(11)) doi:10.3390/tropicalmed9110283.

    PMID: 39591289
  3. 3

    Factors Associated with the Prevalence of Dengue-Leptospirosis Coinfection in Patients Hospitalized for Febrile Syndrome.

    Bance-Anicama DI, Diaz-Orihuela MM, Diaz-Orihuela LM, Morales-García WC

    Tropical medicine and infectious disease 2026; (11(2)) doi:10.3390/tropicalmed11020050.

    PMID: 41746020
  4. 4

    Case report: Weil's disease with multiple organ failure in a child living in dengue endemic area.

    Lokida D, Budiman A, Pawitro UE, et al.

    BMC research notes 2016; (9(1)):407 doi:10.1186/s13104-016-2210-4.

    PMID: 27528203
  5. 5

    Case Report: Leptospirosis Complicated by Persistent, Bilateral Sensorineural Hearing Loss.

    Campbell S, Stewart J, Quail G, et al.

    The American journal of tropical medicine and hygiene 2023; (109(6)):1238-1241 doi:10.4269/ajtmh.23-0100.

    PMID: 37962328
  6. 6

    Sub-internal limiting membrane hemorrhage associated with Weil's disease.

    Alvarez-Torres E, Acaba LA, Berrocal MH

    American journal of ophthalmology case reports 2019; (16()):100546 doi:10.1016/j.ajoc.2019.100546.

    PMID: 31517138
  7. 7

    [Gastrointestinal bleeding and acute hepatic failure by leptospirosis: an entity that should not be forgotten].

    Alventosa Mateu C, Plana Campos L, Larrey Ruíz L, et al.

    Revista de gastroenterologia del Peru : organo oficial de la Sociedad de Gastroenterologia del Peru 2017; (37(1)):96-99.

    PMID: 28489846
  8. 8

    Weil's Disease with Multi-Organ Dysfunction: A Diagnostic Challenge.

    Vivero-Tellez D, Contreras-Ortíz JA, Flores-Martínez E, Gracia-Ramos AE

    Clinical medicine & research 2025; (23(1)):26-31 doi:10.3121/cmr.2025.1963.

    PMID: 40527591
  9. 9

    An Unusual Presentation of Weil's Disease.

    Pal S

    The Journal of the Association of Physicians of India 2019; (67(7)):86-88.

    PMID: 31559782
  10. 10

    Through the Haze of Hemorrhage: Unraveling Leptospirosis With Diffuse Alveolar Hemorrhage.

    Vasireddy M, Logithasan N, Senthil N, et al.

    Cureus 2025; (17(4)):e82006 doi:10.7759/cureus.82006.

    PMID: 40351941
  11. 11

    Pulmonary haemorrhage in Weil's disease.

    Boertjes E, Hillebrand S, Bins JE, Oswald L

    BMJ case reports 2020; (13(1)) doi:10.1136/bcr-2018-227570.

    PMID: 31996379
  12. 12

    Leptospirosis-associated pulmonary hemorrhagic syndrome: immune mechanisms, clinical manifestations, and experimental models.

    Silva LRD, Carneiro MC, Lorga ACM, et al.

    Revista do Instituto de Medicina Tropical de Sao Paulo 2026; (68()):e9 doi:10.1590/S1678-9946202668009.

    PMID: 41637348
  13. 13

    Use of Aminocaproic Acid in Combination With Extracorporeal Membrane Oxygenation in a Case of Leptospirosis Pulmonary Hemorrhage Syndrome.

    Pardinas M, Mendirichaga R, Budhrani G, et al.

    Clinical medicine insights. Circulatory, respiratory and pulmonary medicine 2017; (11()):1179548416686068 doi:10.1177/1179548416686068.

    PMID: 28469503
  14. 14

    Etioepidemiological and Laboratory Profile of Tropical Fever in Patients Presenting With Acute Febrile Illness in Wardha District in Central India: An Observational Study.

    Agrawal S, Khan M, Hamdulay KF, et al.

    Cureus 2025; (17(1)):e77861 doi:10.7759/cureus.77861.

    PMID: 39991430

This page explains the stages and symptoms of leptospirosis for educational purposes only. Always consult a healthcare provider for a proper diagnosis and treatment of your specific symptoms.

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