Sandbox:Leptospirosis
Overview
Leptospirosis is a bacterial zoonotic disorder with ubiquitous distribution,common worldwide, especially in developing countries caused by Leptospira species. Leptospirosis becoming a global public health problem, as evidenced by recent spike in the incidence rates and multiple outbreaks in all continents. The annual estimated incidence of about half a million severe human cases is probably an underestimation, as the disease is severely neglected and its global burden is largely unknown, because of its difficulty in the diagnosis both in clinic and laboratory.
Historical Perspective
Association of renal failure with icteric leptospirosis, was first reported over 100 years ago and described by Adolf Weil. Adolf Weil first described the disease leptospirosis as a disease entity in 1886 and the serious form of leptospirosis called Weil's disease is named after Adolf Weil.
Pathophysiology
The disease leptospirosis involves a spectrum of symptoms ranging from subclinical infection to a severe syndrome of multiorgan infection with high mortality and Weil’s disease represents only the most severe presentation. Severe leptospirosis is frequently caused by serovars of the icterohaemorrhagiae serogroup. The presentation of leptospirosis is biphasic, with the acute or septicemic phase lasting about a week, followed by the immune phase, characterized by antibody production and excretion of leptospires in the urine.[1]
Transmission
Pathogenic leptospires live in the renal system and the genital tracts of domestic animals which act as sites of persistence.[2][3] Bacteria shed from the infected animals such as rodents and domesticat animals through urine. These animals may not show signs of disease, but humans shows signs of illness after contact with infected urine, or through contact with water, soil or food that has been contaminated and the outbreaks are associates with floodwaters. The major route of infection by leptospires is probably by transmission through indirect contact with leptospires secreted into the environment. Humans are considered dead end hosts, but sometimes they also act as carriers. Mammalian species (e.g. rodents, insectivores, dogs, pigs and cattle) act as the main carriers of the disease.[4] Leptospires are excreted in urine into the environment, where they can survive for several months, depending on favourable environmental conditions such as humid and temperate areas. Infection can occurs either by direct contact with the carrier’s urine or through indirect transmission via urine-contaminated environment. The pathogen may also be excreted in the products of abortion in mammalian animal species.[2]
Pathophysiology
Toxin Production | |
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Type of toxin production depends on the serovar
Hemolytic toxins: Hemolysins are produced from several serovars such as serovars ballum, hardjo, pomona, and tarassovi which are sphingomyelinases | |
Immunological Mechanism | |
Humoral Immunity | Innate Immunity |
Acute phase | Immune phase | |
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Anicteric leptospirosis | Icteric leptospirosis |
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Pathology
Pathology |
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Pathological findings of leptospirosis are due to the development of the following:
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Gross Findings |
Gross findings of various organ systems are present as:[9]
|
Histopathological Findings |
Liver:
Kidney:
Heart: Leptospirosis is associate with interstitial myocarditis.[13][14][15][16]
Lungs: Common pulmonary presentation in leptospirosis are pulmonary congestion and hemorrhage.[9][16][17][18]
Skeletal muscle:
Brain:
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Causes
Leptospirosis is caused by various species of Leptospira.
- Family = Leptospiraceae
- Order = Spirochaetales
Not all species of Leptospira are pathogenic, some species are harmless and saprophytes that reside in the environment. Until now there are 50 nonpathogenic serovers and 300 pathogenic serovers are identified.[19] Serovar is the basic unit of Leptospira taxonomy and each serovar consist of closely related isolates based on serological reactions to the bacterial lipopolysaccharide Severe leptospirosis is frequently caused by serovars of the icterohaemorrhagiae serogroup.
Epidemiology and Demographics
Overview
Leptospirosis caused by pathogenic Leptospira species have been found worldwide, except in Antarctica. It is most common in warm, humid environments and in the areas with a high disease incidence in humans include the Caribbean and Latin America, Oceania and parts of Asia. During the past few decades, leptospirosis has become seriously neglected, especially in countries of temperate regions. The main reasons for this situation are probably: 1) a relatively less number of cases noted in the temperate climate zone 2) well established, quite effective methods of therapy and prevention of the disease 3) seemingly well-determined epidemiologic situation concerning the disease.[19]
Prevalence
Leptospirosis, is a zoonotic emerging infectious disease with a worldwide distribution.[20] Tropical climatic conditions are most favourable for survival of leptospires and the morbidity is high due to extreme weather events such as cyclones and floods occurring in recent years.[21][22] Leptospirosis is particularly prevalent in wet tropical and subtropical regions as the pathogenic leptospires can survive longer in a warm and humid environment.
Incidence
Leptospirosis is an increasing public health problem worldwide, evidenced by markedly increasing incidence rates and multiple outbreaks allover the world. Even though multiple outbreaks has been reported, the true spread and incidence of leptospirosis remains unknown, as the availability of diagnostic tests, testing facilities and surveillance systems are highly variable and frequently absent. Incidence rate in temperate climate is in a range of ~0.1–1 per 100000 per year and it is ~10–100 per 100 000 in the humid tropical regions. In high-exposure risk groups and during outbreaks, the incidence may be >100 per 100000.[23]
Case Fatality Rate
Higher morbidity due to leptospirosis is observed in regions with higher proportion of surface fresh waters such as lakes, rivers, developed canal systems.[24][25] Case fatality rate due to leptospirosis is > 10%, and > 500,000 cases of severe leptospirosis are reported each year. Worldwide case fatality rates range from 3%-50%.
Age
Gender
Developed Countries
Developing Countries
Leptospirosis is a neglected disease with a greatest burden on impoverished populations from developing countries and tropical regions.[26]
Risk Factors
The risk of acquiring leptospirosis is associated with contact with animals, which made leptospirosis as an important occupational disease, especially affecting farmers, slaughterhouse workers, pet traders, veterinarians, rodent catchers and sewer workers who are in contact with mammalian species which acts as a natural carriers of leptospires.[20]
Natural History, Complications & Prognosis
Leptospirosis is transported by the natural carriers such as feral, semi-domestic and farm and pet animals.[20] The disease leptospirosis is poorly known and unaware of its natural history is mainly due to the wide range of non specific symptoms, subclinical nature of the disease in animals, and non specific laboratory tests making the disease difficult to diagnose.[27]
Natural History
Natural history of leptospirosis varies with each patient. It might be mild or asymptomatic, and go unrecognized or in some patients the illness may progress to kidney or liver failure, aseptic meningitis, life-threatening pulmonary hemorrhage and other syndromes.
Complications
Complications of leptospirosis are associated with localization of pathogen(Leptospires) within the tissues during the immune phase, eventually present during the second week of the illness.
- Aseptic meningitis
Prognosis
The prognosis of leptospirosis depends upon several known and unknown factors, among which the type of pathogenic serovar and the host’s immune status are the important factors which determines the outcome.[20] Most patients recover completely from leptospirosis, but the duration of recovery varies from months to years with or without late sequelae. The late sequelae may include neuropsychiatric problems such as paresis, paralysis, mood swings and depression etc. The major causes of death include renal failure, cardiopulmonary failure, and haemorrhage. Patients with risk factors such as old age and multiple underlying co-morbid conditions are often associated with more severe leptospirosis and increased mortality.
Daignosis
History & Symptoms
The clinical presentation of leptospirosis is biphasic, with the acute or septicemic phase lasting about a week, followed by the immune phase, characterized by antibody production and excretion of leptospires in the urine.[1] Leptospirosis can occur in several forms, which include mild, flu-like symptoms that may not be recognized as leptospirosis, as well as unusual syndrome or fulminant illness without two distinct phases.
The incubation period of leptospirosis in humans is usually 7 to 12 days, with a range of 2 to 29 days.
Common Symptoms
- Fever
- Myalgias
- Headache
- Chills
- Diarrhoea,
- Nausea and vomiting
- Oliguria/anuria
- Jaundice
- Joint pain
- Skin rash
- Cough
- Psychosis
- Delirium
Clinical Manifestations
Clinical manifestations of leptospirosis varies depending upon the serovar and also the host immunity. Typically, leptospirosis presents broadly into 4 clinical catogiries:[28]
- Mild, influenza-like illness
- Weil's syndrome characterized by jaundice, renal failure, haemorrhage and myocarditis with arrhythmias
- Meningitis or Meningoencephalitis
- Pulmonary haemorrhage with respiratory failure
Laboratory Findings
As the clinical manifestations of the disease are non specific, the clinical diagnosis is difficult. The laboratory investigations for leptospirosis should be considered in patient with an abrupt onset of fever, chills, conjunctival suffusion, headache, myalgia and jaundice with history of occupational exposure to infected animals or contaminated with animal urine.[29] Laboratory investigations useful in the diagnosis of leptospirosis include:
- Identification of leptospires in tissues using antibodies labelled with fluorescent markers
- Antibody detection by serological studies
- Culture the bacteria from blood, urine or tissues
- Other methods such as PCR, Immunostaining etc.
Treatment
Medical Therapy
For effective treatment of leptospirosis, antibiotics should be used within 5th day after the onset of symptoms and as soon as the diagnosis of leptospirosis is suspected without waiting for the laboratory results.[30] Best initial treatment for severe leptospirosis is Penicillin. For less severe form, drugs such as amoxycillin, ampicillin, doxycycline or erythromycin can be used. Other drugs of choice which are effective, include third-generation cephalosporins, such as ceftriaxone and cefotaxime, and quinolone antibiotics.[31]
Primary Prevention
Secondary Prevention
For leptospirosis there is no specific vaccines for prevention, but it can be prevented by proper disinfection such as 1% sodium hypochlorite, 70% ethanol, iodine-based disinfectants, quaternary ammonium disinfectants, accelerated hydrogen peroxide, glutaraldehyde, formaldehyde, detergents and acid or by pasturization. These organisms are also sensitive to moist heat (121°C [249.8°F] for a minimum of 15 min).
References
- ↑ 1.0 1.1 Levett, P. N. (2001). "Leptospirosis". Clinical Microbiology Reviews. 14 (2): 296–326. doi:10.1128/CMR.14.2.296-326.2001. ISSN 0893-8512.
- ↑ 2.0 2.1 Ellis WA, O'Brien JJ, Cassells JA, Neill SD, Hanna J (1985). "Excretion of Leptospira interrogans serovar hardjo following calving or abortion". Res Vet Sci. 39 (3): 296–8. PMID 4081333.
- ↑ Ellis WA, McParland PJ, Bryson DG, Thiermann AB, Montgomery J (1986). "Isolation of leptospires from the genital tract and kidneys of aborted sows". Vet Rec. 118 (11): 294–5. PMID 3705357.
- ↑ Ganoza CA, Matthias MA, Saito M, Cespedes M, Gotuzzo E, Vinetz JM (2010). "Asymptomatic renal colonization of humans in the peruvian Amazon by Leptospira". PLoS Negl Trop Dis. 4 (2): e612. doi:10.1371/journal.pntd.0000612. PMC 2826405. PMID 20186328.
- ↑ Budihal, Suman Veerappa (2014). "Leptospirosis Diagnosis: Competancy of Various Laboratory Tests". JOURNAL OF CLINICAL AND DIAGNOSTIC RESEARCH. doi:10.7860/JCDR/2014/6593.3950. ISSN 2249-782X.
- ↑ BEESON PB, HANKEY DD (1952). "Leptospiral meningitis". AMA Arch Intern Med. 89 (4): 575–83. PMID 14902167.
- ↑ King SD, Urquhart AE (1975). "Laboratory investigations on four cases of leptospiral meningitis in Jamaica". West Indian Med J. 24 (4): 196–201. PMID 1224630.
- ↑ Silva MV, Camargo ED, Batista L, Vaz AJ, Ferreira AW, Barbosa PR (1996). "Application of anti-leptospira ELISA-IgM for the etiologic elucidation of meningitis". Rev Inst Med Trop Sao Paulo. 38 (2): 153–6. PMID 9071036.
- ↑ 9.0 9.1 9.2 9.3 AREAN VM (1962). "The pathologic anatomy and pathogenesis of fatal human leptospirosis (Weil's disease)". Am J Pathol. 40: 393–423. PMC 1949541. PMID 13862141.
- ↑ De Brito T, Machado MM, Montans SD, Hoshino S, Freymüller E (1967). "Liver biopsy in human leptospirosis: a light and electron microscopy study". Virchows Arch Pathol Anat Physiol Klin Med. 342 (1): 61–9. PMID 4298629.
- ↑ PENNA D, DE BRITO T, PUPO AA, MACHADO MM, AYROZA PA, DE ALMEIDA SS (1963). "KIDNEY BIOPSY IN HUMAN LEPTOSPIROSIS". Am J Trop Med Hyg. 12: 896–901. PMID 14072448.
- ↑ Sitprija, Visith; Evans, Hilary (1970). "The kidney in human leptospirosis". The American Journal of Medicine. 49 (6): 780–788. doi:10.1016/S0002-9343(70)80059-6. ISSN 0002-9343.
- ↑ De Biase L, De Curtis G, Paparoni S, Sciarra D, Campa PP (1987). "Fatal leptospiral myocarditis". G Ital Cardiol. 17 (11): 992–4. PMID 3446572.
- ↑ Brito, T. De; Morais, C. F.; Yasuda, P. H.; Lancellotti, Carmen P.; Hoshino-Shimizu, Sumie; Yamashiro, E.; Alves, V. A. Ferreira (2016). "Cardiovascular involvement in human and experimental leptospirosis: Pathologic findings and immunohistochemical detection of leptospiral antigen". Annals of Tropical Medicine & Parasitology. 81 (3): 207–214. doi:10.1080/00034983.1987.11812114. ISSN 0003-4983.
- ↑ AREAN VM (1957). "Leptospiral myocarditis". Lab Invest. 6 (5): 462–71. PMID 13464040.
- ↑ 16.0 16.1 Ramachandran S, Perera MV (1977). "Cardiac and pulmonary involvement in leptospirosis". Trans R Soc Trop Med Hyg. 71 (1): 56–9. PMID 871034.
- ↑ Nicodemo AC, Duarte MI, Alves VA, Takakura CF, Santos RT, Nicodemo EL (1997). "Lung lesions in human leptospirosis: microscopic, immunohistochemical, and ultrastructural features related to thrombocytopenia". Am J Trop Med Hyg. 56 (2): 181–7. PMID 9080878.
- ↑ Zaltzman M, Kallenbach JM, Goss GD, Lewis M, Zwi S, Gear JH (1981). "Adult respiratory distress syndrome in Leptospira canicola infection". Br Med J (Clin Res Ed). 283 (6290): 519–20. PMC 1507945. PMID 6790049.
- ↑ 19.0 19.1 Hartskeerl RA, Collares-Pereira M, Ellis WA (2011). "Emergence, control and re-emerging leptospirosis: dynamics of infection in the changing world". Clin Microbiol Infect. 17 (4): 494–501. doi:10.1111/j.1469-0691.2011.03474.x. PMID 21414083.
- ↑ 20.0 20.1 20.2 20.3 Levett PN (2001). "Leptospirosis". Clin Microbiol Rev. 14 (2): 296–326. doi:10.1128/CMR.14.2.296-326.2001. PMC 88975. PMID 11292640.
- ↑ Lau CL, Smythe LD, Craig SB, Weinstein P (2010). "Climate change, flooding, urbanisation and leptospirosis: fuelling the fire?". Trans R Soc Trop Med Hyg. 104 (10): 631–8. doi:10.1016/j.trstmh.2010.07.002. PMID 20813388.
- ↑ Vijayachari P, Sugunan AP, Shriram AN (2008). "Leptospirosis: an emerging global public health problem". J Biosci. 33 (4): 557–69. PMID 19208981.
- ↑ LastName, FirstName (2003). Human leptospirosis : guidance for diagnosis, surveillance and control. Geneva: World Health Organization. ISBN 9241545895.
- ↑ Jansen A, Schöneberg I, Frank C, Alpers K, Schneider T, Stark K (2005). "Leptospirosis in Germany, 1962-2003". Emerg Infect Dis. 11 (7): 1048–54. doi:10.3201/eid1107.041172. PMC 3371786. PMID 16022779.
- ↑ Baranton G, Postic D (2006). "Trends in leptospirosis epidemiology in France. Sixty-six years of passive serological surveillance from 1920 to 2003". Int J Infect Dis. 10 (2): 162–70. doi:10.1016/j.ijid.2005.02.010. PMID 16298537.
- ↑ McBride AJ, Athanazio DA, Reis MG, Ko AI (2005). "Leptospirosis". Curr Opin Infect Dis. 18 (5): 376–86. PMID 16148523.
- ↑ Vieira ML, Gama-Simões MJ, Collares-Pereira M (2006). "Human leptospirosis in Portugal: A retrospective study of eighteen years". Int J Infect Dis. 10 (5): 378–86. doi:10.1016/j.ijid.2005.07.006. PMID 16600656.
- ↑ LastName, FirstName (2003). Human leptospirosis : guidance for diagnosis, surveillance and control. Geneva: World Health Organization. ISBN 9241545895.
- ↑ LastName, FirstName (2003). Human leptospirosis : guidance for diagnosis, surveillance and control. Geneva: World Health Organization. ISBN 9241545895.
- ↑ LastName, FirstName (2003). Human leptospirosis : guidance for diagnosis, surveillance and control. Geneva: World Health Organization. ISBN 9241545895.
- ↑ LastName, FirstName (2003). Human leptospirosis : guidance for diagnosis, surveillance and control. Geneva: World Health Organization. ISBN 9241545895.