|Year : 2022 | Volume
| Issue : 4 | Page : 517-521
Seroprevalence of acute leptospirosis in a tertiary care hospital of western India
Bhumika Baveja, Meghna S Palewar, Suverna Joshi, Rajesh Karyakarte
Department of Microbiology, B. J. Government Medical College, Pune, Maharashtra, India
|Date of Submission||12-Mar-2022|
|Date of Acceptance||08-Nov-2022|
|Date of Web Publication||29-Dec-2022|
Dr. Rajesh Karyakarte
Department of Microbiology, B. J. Government Medical College, Pune 411001, Maharashtra
Source of Support: None, Conflict of Interest: None
Background: Leptospirosis is a widespread re-emerging zoonotic disease, especially in developing countries. According to World Health Organization, despite being severe, the disease is neglected in most endemic countries because of a lack of information and awareness about the extent of the problem. Objective: The objective was to study the seroprevalence and epidemiology of leptospirosis with its biochemical correlation in the general population in Pune, Maharashtra. Materials and Methods: It is a retrospective observational laboratory-based study over 1 year from January to December 2020 in a tertiary care hospital in western India. A total of 561 blood specimens received during 1 year for the diagnosis of fever were processed for Leptospira IgM antibodies using enzyme-linked immunosorbent assay (ELISA). Results: A total of 111 of 561 blood specimens that were received during the study period tested positive for IgM antibody against Leptospira. The seroprevalence of Leptospira spp. was found to be 19.78%. In seropositive patients, the age ranged from 4 to 77 years. The highest seropositivity was observed in the age group of 21–30 years (42%). There were 34% (n = 38) males and 66% (n = 73) females, among those who tested positive. Seroprevalence in Pune was highest in the months of June–August. Renal function tests were deranged in 44 (39.63%) patients (serum creatinine > 1.5 mL). Hyponatremia and hypokalemia were observed in 37.84% and 21.62% of patients, respectively. In liver function tests, serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) both were deranged (SGOT > 40 U/L; SGPT > 56 U/L) in 36 (32.43%) patients, whereas SGOT alone was deranged in additional 18 patients (48.64%). Serum bilirubin was deranged in 65.45%. Coinfection was observed with chikungunya, dengue, and malaria in 7.2%, 6.3%, and 0.90% of patients, respectively. Conclusion: Because morbidity is high in this infection, early diagnosis of leptospirosis is essential because antibiotic therapy provides the greatest benefit when initiated early in the course of illness.
Keywords: IgM antibodies, leptospirosis, renal function tests, seroprevalence
|How to cite this article:|
Baveja B, Palewar MS, Joshi S, Karyakarte R. Seroprevalence of acute leptospirosis in a tertiary care hospital of western India. MGM J Med Sci 2022;9:517-21
|How to cite this URL:|
Baveja B, Palewar MS, Joshi S, Karyakarte R. Seroprevalence of acute leptospirosis in a tertiary care hospital of western India. MGM J Med Sci [serial online] 2022 [cited 2023 Feb 7];9:517-21. Available from: http://www.mgmjms.com/text.asp?2022/9/4/517/365978
| Introduction|| |
Leptospirosis is a widespread re-emerging zoonotic disease, especially in developing countries. This has been recognized as a global health problem because of its epidemic proportions. It is an infectious disease caused by pathogenic spirochetes from the genus Leptospira. These are Gram-negative bacteria. Leptospirosis is seen in widespread geographic zones such as tropical, subtropical, and temperate zones. According to World Health Organization, the disease is neglected in endemic countries because of a lack of information and awareness about the extent of the problem, despite it being severe. The disease is endemic in Maharashtra, Karnataka, Kerala, Tamil Nadu, and Andaman and Nicobar Islands, despite being underreported in developing nations.,
Leptospirosis is also known as “the Great Mimicker” and may be overlooked or underdiagnosed because of its varied clinical presentation.
Leptospirosis is a direct zoonotic infection. Leptospira’s lifecycle is maintained in nature by several animal hosts. The pathogen is shed in the urine of the carrier animals like rodents and can survive in the environment for a prolonged time. Humans are accidental hosts, and the infection is acquired through contact of abraded skin with soil or water contaminated by the urine of reservoir animals. The pathogen, Leptospira interrogans, excreted in the urine contaminates the water bodies during monsoons or natural calamities leading to outbreaks. It is also called “rice field fever” or “mud fever.” This name is based on the transmission of disease, i.e., humans mostly farmers, coming in contact with contaminated water. The source and load of infection in an area are determined by factors such as rodent density, domestic animals, and sanitation.
Occupational exposure is one of the major causes of infection, seen more in the risk groups such as farmers, workers in sewers, veterinarians, meat handlers, and animal handlers. The incubation period of the disease is 5–7 days. Leptospirosis usually presents as fever within 7 days as the main symptom. This disease can range from subclinical infection to a severe syndrome that may be characterized by multiorgan failure. Major clinical features include headache, fever, myalgia, jaundice, bleeding tendency, oliguria, and even pulmonary manifestations such as cough and hemoptysis.
A small fraction of patients develops severe icteric illness along with renal failure. In all, 5%–10% of leptospirosis infections may lead to multiple organ failures. Cardiac and pulmonary complications are frequently encountered, and sudden death may occur from arrhythmias or cardiac failure. Weil’s syndrome, the most severe form of infection, presents with febrile illness along with hemorrhagic tendencies, hepatic dysfunction, and acute renal failure leading to fatality in a short time if the disease is left untreated.
The isolation of the causative organism from the clinical specimen is low because of a prior use of antibiotics and expensive isolation techniques. Most of the techniques available apart from this are tedious, cumbersome, and time-consuming. Thus, this makes serological testing a cornerstone of diagnosing leptospirosis.
This study was conducted to study the prevalence and clinical profile of leptospirosis in a tertiary care hospital in Pune, Maharashtra.
| Aims and objectives|| |
The aims and objectives of the study were:
- To study the seroprevalence and epidemiology of leptospirosis in febrile patients attending a tertiary care hospital in Pune.
- To correlate the positive results with their clinical profile.
| Materials and methods|| |
The present study is a retrospective and descriptive review of records of leptospirosis cases diagnosed at the Department of Microbiology in BJ Government Medical College and Sassoon Hospital, Pune, India. The study was conducted from January 2020 to December 2020. During this period, 561 blood specimens were received from suspected cases of pyrexia of unknown origin for the diagnosis of fever. These were processed for Leptospira IgM antibodies using NovaLisa Leptospira IgM enzyme-linked immunosorbent assay (ELISA) kit (manufactured by NOVATEC immunodiagnostica GmbH, Dietzenbach, Germany). The test procedure was performed according to the protocol provided in the kit insert by the manufacturer.
Results were then analyzed based on the instruction manual provided by the manufacturer. A score of less than 9 NovaTec units (NTUs) indicated a negative result or no detectable IgM antibody, 9–11 NTUs as equivocal, and more than 11 NTUs as a positive result, indicating the presence of Leptospira IgM antibodies. Positive and negative test controls were tested in each run along with the samples. Single-trained laboratory technicians performed the ELISA test to avoid bias.
All the patients with positive results for Leptospira IgM results were considered Leptospira seropositive, and all those negative for Leptospira IgM were considered not infected with Leptospira.
For the Leptospira IgM-positive patients, all the clinical and laboratory profiles during the study period were considered and analyzed. For controls of the laboratory profiles, we considered the biochemical and hematological data of age- and sex-matched healthy individuals, as the cut-off for the tests.
| Results|| |
In all, 111 specimens out of 561 tested positive for the IgM antibody of Leptospira. The prevalence of leptospirosis was found to be 19.78%. Among the 111 patients who tested positive for IgM, 34% were male (38/111) and 66% (73/111) female [Figure 1]. In positive patients, the age ranged from 4 to 77 years. The highest seropositivity was observed in the age group of 21–30 years [Figure 2]. Seropositivity of acute leptospirosis in Pune was highest in the monsoon months of June to August followed by the winter months of October to December [Figure 3].
|Figure 3: Seasonal distribution of seropositivity of acute leptospirosis cases|
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Renal function tests were deranged in 44 (39.63%) patients for serum creatinine > 1.5 mL, 42 (37.8%) patients for serum urea, and 34 (30.63%) patients for serum uric acid. In liver function tests, serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) were both deranged (SGOT > 40 U/L; SGPT > 56 U/L) in 36 (32.43%) patients. SGOT alone was deranged in additional 18 patients (48.64%). Serum bilirubin was deranged in 65.45% of patients. We also observed hyponatremia and hypokalemia in 37.84% and 21.62% of patients, respectively [Table 1].
|Table 1: Deranged kidney function test, liver function test, and other biochemicals in patients with acute leptospirosis cases|
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In this study, there was coinfection of leptospirosis with chikungunya, dengue, and malaria in eight patients (7.2%), seven patients (6.3%), and one patient (0.90%), respectively [Table 2].
| Discussion|| |
Leptospirosis is a zoonotic disease that has humans as accidental hosts. During the early clinical presentation, it is often indistinguishable from other common causes of acute febrile illness in tropical countries such as dengue fever, malaria, typhoid, and others. Clinical manifestations of leptospirosis can range from inapparent infection to fulminant disease. There are no pathognomonic symptoms or signs in the initial phase of disease or the septicemic phase of illness. History of contact with animals, stagnant water, or poor sanitization should point toward leptospirosis. Victoriano et al. (2009) stated that countries such as Bangladesh, India, Laos, Sri Lanka, and Thailand have a high incidence of leptospirosis, with an annual incidence of more than 10 per 100,000 population. The overall disease burden is underestimated, yet leptospirosis is a significant cause of undifferentiated fever, which is frequently not recognized.
In the present study, IgM ELISA was used for the diagnosis of leptospirosis. The seroprevalence of leptospirosis was seen in 19.78% of cases with a fever of 5 or more days. Cases with at least a minimum of 5 days of fever were considered as this provides time for immune system to produce IgM antibodies detectable using IgM ELISA.
According to National guidelines in the Programme for Prevention and Control of Leptospirosis, 20–45 years was the most affected age group. We found the maximum incidence in 21–30 years of age followed by 31–40 years. This is owing to leptospirosis being an occupational hazard and thus seen mostly in the working young population. In our study, we found females (64%) to be more predisposed to the infection as compared to males. In another study, conducted in Maharashtra, a similar finding was observed. This may be owing to the involvement of women in taking care of cattle and being a part of an economically productive age group.
In India, leptospirosis is a major health problem related both to the monsoons and poor sanitary conditions, with multiple epidemics reported in recent years. Because of local agricultural practices and improper waste disposal, the likelihood of contact with Leptospira-contaminated environment increases.
The highest incidence of leptospirosis was in June and July, owing to the monsoons in Maharashtra. In other studies also, the caseload was highest in monsoons. The pathogen L. interrogans is excreted in the urine of rodents and contaminates the water bodies leading to outbreaks. This is seen more in monsoons or natural calamities.
Impaired renal function tests and liver function tests are usually accompanied by hyperbilirubinemia. In all, 65% of patients with positive IgM had deranged bilirubin; similar results (60%) were found in a couple of tertiary care hospital studies in India., In leptospirosis, jaundice is seen due to hepatocellular necrosis and increased load of bilirubin from tissue hemorrhage. The liver may be enlarged and tender. Transaminases may be mildly elevated, which is a characteristic feature. Despite all of this, hepatic failure is rarely the cause of death. Holla et al., in a study conducted in south India, found the SGOT to be raised in 73%, serum urea in 63.9%, and creatinine levels raised in 53% of the population. In our study, we saw similar derangements, but in a slightly lesser percentage of 48.64%, 37.83%, and 39.63%, respectively. Additionally, we found raised serum uric acid in 30.63% of patients. According to Yang, leptospiral exposure may cause subclinical kidney injury. Renal manifestations such as oliguria, pyuria, hematuria, granular casts, or even renal failure may be seen. Renal involvement is the most common cause of death in leptospirosis.
Hyponatremia, hypokalemia, and hypophosphatemia are often encountered in tropical diseases especially so in severe cases. Hypokalemia observed in leptospirosis is often attributed to respiratory alkalosis seen secondary to respiratory complications. Also, according to Andrade et al., hypokalemia in leptospirosis-induced acute renal failure (ARF) is due to renal potassium loss aggravated by cortisol. Clinically potassium replacement thereby becomes an important aspect to be taken care of.
The incidence of hypokalemia was found to be 21.62% in our study, which was comparable to that of 20% hypokalemia reported by Khositseth et al. The same was reported to be 26%–45% by Sitprija. We also observed hyponatremia in 37.84% of the IgM-positive patients as compared to the 30% observed by Khositseth et al. Hyponatremia is associated with the severity of leptospirosis and bad prognosis, so it should be considered as a parameter to guide the clinician in critical care of the patients.
We also found coinfection with dengue in 6.3% of cases and 7.2% coinfection with chikungunya in patients with leptospirosis. IgM ELISA was performed for both dengue and chikungunya. These results seemed a little higher compared to another study. In a study by Sharma et al., it was emphasized that in an endemic area, leptospirosis may be confused with dengue fever because of similar clinical features and there being no pathognomonic clinical feature limited to leptospirosis.
Because morbidity is high in this infection, early diagnosis of leptospirosis is essential because antibiotic therapy provides the greatest benefit when initiated early in the course of the illness. To successfully tackle the problem of leptospirosis, it should be considered an important part of the differential diagnosis of fever of unspecified origin.
| Conclusions|| |
Leptospirosis is a potentially fatal re-emerging disease with a growing number of cases worldwide. In a developing nation like India, it is still underreported and underdiagnosed, despite being endemic due to various risk factors (like agrarian lifestyle) that predispose the population to the disease. With 19.78% prevalence in people with febrile illness attending a tertiary care hospital, it becomes an important differential diagnosis in a fever of unknown origin. Awareness and proactive steps for the prevention of spread, early diagnosis, and proper treatment of leptospirosis are needed. Apart from this, efforts should be made to improve the diagnostic tests and use an accurate diagnostic tool, as early diagnosis can be life-saving if appropriate antibiotic therapy is initiated early in a course of illness.
The Institutional Ethics Committee of B. J. Government Medical College, Pune, Maharashtra, India had reviewed the research proposal in its meeting held on October 14, 2022, and subsequently approved undertaking the study protocol vide their letter no. BJGMC/IEC/Pharmac/ND-Dept./1022232-232 dated October 14, 2022.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]