European Journal of Cardiovascular Medicine

Acute Febrile illness (AFI) with non-specific symptoms and signs is one of the most common clinical presentation to healthcare services in developing countries [1]. Leptospirosis is an emerging anthropozoonotic infection caused by the pathogenic Leptospira spp. [2]. Leptospirosis is worldwide in distribution, however it occurs more   commonly in the tropics and subtropics, which are areas with heavy rainfall [3]. The whole region of Southeast Asia is an endemic area for leptospirosis. According to the World Health Organisation (WHO) reports, the incidences range from approximately 0.1-1 per 1,00,000 per year in temperate climates to 10-100 per 1,00,000 in the humid tropics [4]. Rodents and domestic animals such as cattle, pigs and dogs  serve as  major reservoir hosts. Humans are accidental hosts which are infected by direct or indirect exposure to the urine of carrier animals. Common       epidemiogical risk factors favouring disease spread are residing         in proximity to reservoir animals, high temperature, rainfall, water logging, poor sanitation and outdoor occupations [5]. Organism enters the host through skin abrasions, mucosal surfaces or the eye. Incubation period ranges from 3 to 30 days; usually 10-12 days. The clinical  spectrum of the disease range from subclinical infections to severe fatal complications and Weil’s syndrome. Clinical presentations include fever, headache, myalgia, conjunctival suffusion, rash, hepatosplenomegaly, haemorrhagic manifestations, renal failure, icterus, aseptic meningitis, Acute Respiratory Distress Syndrome (ARDS) and pulmonary haemorrhage [2].

The study was conducted in the Department of Microbiology, Kurnool Medical College, Kurnool from August 2023 to March 2024 under the section of NOHP-PCZ (NCDC). Our institute was identified as one of the Sentinel Surveillance sites under NOHP-PCZ (NCDC) in 2022. The study was approved by the Institutional Ethical Committee.

A total of 260 blood samples were collected from clinically suspected cases of Leptospirosis attending either outpatient department or admitted in wards of General Medicine, Pediatrics, Obstetrics and Gynecology, Surgery, Neurology and Gastroenterology of Government General Hospital, Kurnool.

Inclusion criteria - All patients who were suspected clinically of Leptospirosis and presented with a history of fever for more than 7 days accompanied with any of the following features i.e., severe headache, myalgia, arthralgia, conjunctival suffusion, uveitis, rash, hepatosplenomegaly, hemorrhagic manifestations, renal failure, aseptic meningitis, Acute respiratory distress syndrome [8].

Blood   was allowed to clot and serum was separated. The samples were  tested for the detection of IgM antibodies for Leptospirosis using the Recombilisa Leptospira IgM ELISA kit. Test was carried out as per manufacturer’s instructions.

Result interpretation was as follows:

Cut off value= 0.244+Negative control OD

Specimen OD ratio = Specimen OD/Cut off value

Negative<1.00 Specimen OD ratio

Positive>=1.00 Specimen OD ratio

Out of 260 AFI cases suspected of Leptospirosis, 30 (11.53%) were positive for Leptospirosis IgM antibodies. Among 142 male and 118 female AFI cases, 20 males (14.1%) and 10 females (8.5%) were Leptospirosis positive respectively. The majority of AFI cases belonged to the 21-40 years age group followed by the 41-60 years. Highest seroprevalence of Leptospirosis was found in the age group of 21-40 years in both males and females [Figure 1]. Out of 260 cases, 160 (61.53%) belonged to rural area and were involved in occupation of agriculture, poultry, dairy and labour; 90 (34.61%) belonged to urban area and were involved in occupation of construction, labour, garbage cleaning and self-employment. Most of the cases below 20 years were students and few from rural area were involved in agriculture. 10 cases (4%) were non-local, from Telangana state [Figure 2]. The association of seroprevalence with gender,   age and occupation was found to be statistically significant (p-value<0.05). Fever was reported in all cases (100%). Other common symptoms were myalgia (76.9%), headache (73.1%) and abdominal pain (57.7%). Most common sign was Jaundice (51.9). History of contact with rodents and live stock was found in 125 cases (48.1%) [Figure 3].

The present study evaluated the seroprevalence of Leptospirosis along with the associated epidemiological risk factors. Seroprevalence was estimated to be 11.53 % in our study. 17.2% seroprevalence was seen in a study in Punjab [9], 17.8% was seen in study in Chennai [10]. However, Mansoor T et al., reported  low seroprevalence (6.4%) in a study from the Kashmir valley [11]. This may be attributed to the climate conditions of the region. Seroprevalence was found to be higher in Males (14.1%) as compared to Females (8.5%)

 Males (66.7%) showed higher positivity as compared to females (33.3%) in our study owing to the more outdoor activities by men as compared to women. This observation correlates well with other similar studies in India [12,13].  Ahmad N et al., reported that males constituted 66.7% of total cases [14]. The male majority was also observed by Kumari P et al., (60%), Moinuddin SK and Nazeer HA (70.6%)      and Banukumar S (60.4%) [15, 16].

The most common presenting feature was fever with myalgia and headache. This finding was consistent with other similar studies from India [17]. The seroprevalence of the 21-40 years age group was significantly higher than other age groups. These findings were in concordance with other studies [6,9] as this age group is more exposed to risk factors. Agriculture, dairy and poultry were major occupational groups among Leptospirosis cases. More than 50% of the patients affected by Leptospirosis were outdoor manual workers. Studies by Ahmad N et al., (50%) and Srinath M et al., (32%) have shown agriculture as a predominant occupation [14,18]. The seasonal variation was observed in this study though the study was started in August. During the monsoon season, a higher seroprevalence rate was observed, which was consistent with the previous studies [13].  Out of  the diagnosed patients, majority were treated for  Leptospirosis and showed significant improvement during the follow-up period.

In our study we used ELISA to study the seroprevalence of Leptospirosis in our hospital. ELISA can prove to be a very useful tool for diagnosis in resource-limited settings. In several regions of India, leptospirosis has quickly taken the lead as the primary cause of AFI. Leptospirosis and other AFIs are difficult to diagnose clinically due to their non-specific and overlapping clinical characteristics. An improvement in sanitation, hygiene, and socioeconomic circumstances will result in a decline in the Leptospirosis seroprevalence rate. Because this zoonotic disease can lead to potentially fatal consequences, it needs to be diagnosed quickly and treated with a high degree of suspicion. As part of NOHP-PCZ, a programmatic approach to the prevention, control, and management of Leptospirosis is strongly advised and support from all sectors is recommended.

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