Introduction
Leptospirosis is a a rapidly re-emerging anthropo-zoonotic disease caused by pathogenic spirochaetes of the genus Leptospira and transmitted to man under certain environmental conditions like floods, cyclones and other natural calamities. It is believed to be the most prevalent zoonosis across the globe.1 In a multi-centric study in India, 12.7% of cases of acute febrile illness reporting to the hospitals were attributed to leptospirosis.2 Armed Forces personnel are at increased risk of contracting leptospirosis during relief work following floods and other natural disasters.
The disease may pass off unnoticed and under-reported at times due to a wide range of signs and symptoms and difficulty in establishing a confirmatory laboratory diagnosis; especially in peripheral settings. Because of lack of awareness of the disease, inadequate epidemiological data, and unavailability of appropriate laboratory diagnostic facilities in most parts of the world, leptospirosis has unfortunately acquired the status of a “neglected disease”.3
Materials and methods
Two cases of leptospirosis reporting to two different service hospitals located in the southern part of the country are reported here. Both cases were admitted and subjected to detailed epidemiological investigation including history regarding personal information, presenting symptoms, time of onset of symptoms, medical care provided and time required taken for recovery or death. As the cases presented differently, they were managed based on their clinical presentation. While the first case succumbed to his illness despite intensive management, the second case had a mild illness and was discharged after treatment.
Assessment of the clinico-epidemiological profile of the cases led to the incrimination of leptospira as the causative agent. A confirmed case was therefore defined as one presenting with acute febrile illness and positive laboratory test for Leptospirosis.
Results
Case 1
This 52 yrs old male ex serviceman working as a farmer, presented with a history of high grade fever with chills and rigors of 4 – 5 days duration. He had reduced urine output since the last two days and became anuric at the time of reporting. He had hypotension and tachyponea with deep icterus , pallor, pedal edema and bleeding from all intravenous sites .Systemic examination showed epigastric tenderness with bilateral basal crackles in chest. Investigation showed low platelet counts (10,000/cumm) with hyperbilirubinemia ( serum bilirubin – 17.3 mg/dl), raised SGOT/SGPT ( 108/41 IU/L), and azotemia ( BUN -69 mg/dl , creatinine -4.9 mg/dl) . Tests for malarial parasite and all viral markers like HBV, HCV, HAV, HEV & Dengue was negative. Test for IgM antibodies for leptospira was positive.
The case was intubated and mechanically ventilated due to poor sensorium (E1V1M2). He was started on peritoneal dialysis, but as he did not respond to same, he was taken up for hemodialysis. His further course was complicated with development of aspiration pneumonia, progressively rising serum bilirubin aand azotaemia with dyselecrolytemia. He finally expired due to multi-organ dysfunction on the eighth day following admission.
Case 2
A 22 year old wife of a sailor, residing in a metropolitan city in South India presented with high grade fever, body ache and sore-throat of one week duration. She gave history of wading through knee-deep water post-floods on three successive days to purchase household items. She was negative for malaria, dengue and typhoid. Although she was negative for IgM antibodies for Leptospira and dark filed microscopy, she turned out to be positive for MSAT (2+) and MAT (1: 80). She did not develop any complications and was discharged after five days following a course of oral antibiotics.
Discussion
Leptospirosis is endemic in humid subtropical and tropical climates. The disease is prevalent in areas of heavy monsoons coupled with animal rearing and unplanned urbanisation.4 It is an occupational hazard for farmers, sewage workers, foresters and butchers. Troops deployed in disaster affected areas also constitute a high-risk group. One of the two cases described here was a farmer. An Iranian study5 found farming as the major (60%) occupation among infected patients.. The reason for increased risk in farmers is mainly due to the heavy use of fertilizers for agriculture, which makes the pH of the water alkaline, thereby making the environment conducive for survival and propagation of Leptospira. 6
In endemic regions, the disease generally presents as an asymptomatic or mild illness. It flares up as outbreaks primarily during natural calamities wherein hygiene and sanitation standards get compromised due to time and space constraints. Humans are accidental deade-end hosts and usually become infected through from direct or indirect exposure to the urine of infected animals such as rodents, dogs and cattle.7 Flooding after torrential rains is remarkably favourable for leptospirosis. As flooding prevents animal urine from being absorbed into the soil or evaporating, it allows leptospires to persist for prolonged duration in the surface water.8 Continued exposure of the skin to contaminated water therefore provides an excellent opportunity for invasion by leptospires.
As seen in the above two cases, the clinical signs and symptoms are highly variable and may range from subclinical to fulminant and potentially fatal manifestations.9 If untreated, the mortality rates may be high in severe cases. Timely diagnosis is crucial as antibiotic therapy provides greatest benefit when initiated early.10Hence, it is imperative that Leptospirosis should also be considered in the differential diagnosis of acute febrile illnesses of unknown origin.
As troops involved in flood relief operations are at high risk of contracting leptospiral infection, they must be briefed about preventive aspects before deployment. Walking through dirty water should be avoided as far as possible. However, when the same is inevitable, protective gear in the form of gumboots, rubber gloves and full sleeves clothes should be worn when wading through water logged areas to prevent man – pathogen contact. Wounds, cuts or abrasions should be well covered and bandaged. Improvement in sanitation and hygiene of the camping area helps in preventing spread of the disease. Domestic animals should be kept separately and handled carefully. Drinking water should be boiled to prevent disease transmission. Proper disposal of wastes should be ensured. Troops should be cautioned to avoid swimming in infected pools and ponds.
As leptospirosis has great potential for causing outbreaks, disease surveillance measures should be put in place. Medical Officers should maintain a high index of suspicion of leptospirosis in floods and other natural disasters; as timely recognition may make the difference between recovery and fulminant or fatal outcome.
Information Education and Communication (IEC) activities for troops regarding preventive measures against leptospirosis should be undertaken by medical officers. Regular training and retraining of medical officers in their role of trainers is therefore of paramount importance.
We must reconcile with the fact that leptospirosis cannot be eradicated; keeping in view the large variety of serovars, multiple sources of infection and non-availability of a potent vaccine. However, meticulous rodent control measures and improvement in sewerage and drainage facilities will go a long way in outbreak mitigation.