LEPTOSPIROSIS
LEPTOSPIROSIS: AN IGNORED INFECTIOUS DISEASE FOLLOWING FLOODS
INTRODUCTION:
Natural disasters usually lead to disturbances in the eco system and creates multiple hazards to
human as well as animal health. The most commonly encountered natural disaster include floods,
which are highly prevalent in Asian countries. Floods are commonly caused due to heavy rains,
river and coastal floods, and human interferences (e.g. deforestation). Risk factors such as
overcrowding, disruption of sewage disposal, poor
standards of hygiene, poor nutrition, negligible sanitation
and human contact among refugees provide suitable
conditions for increasing the incidence of infectious
diseases after flooding and can cause epidemics.
Leptospirosis, Schistosomiasis, Melioidosis, Cholera were
some of the infectious diseases documented following
flood events.
Leptospirosis is an infectious disease caused by pathogenic bacteria that belongs to genus
Leptospira. It is transmitted directly or indirectly
from animals to humans (Zoonosis). It affects
humans as well as animals. In humans clinical
manifestations range from mild to lethal with broad
spectrum of signs and symptoms, some of which
may be mistaken for other diseases. However, few
individuals, have no symptoms at all. Leptospirosis
is of two types anicteric and icteric (severe form and
associated with multi organ involvement).
Leptospirosis is widespread all over the world but is
highly prevalent in tropical and sub-tropical regions with high rainfall.
EPIDEMIOLOGY:
The estimated annual incidence of leptospirosis is 0.1 to 1 per 1,00,000 per year in temperate
climates whereas in humid climates it is 10 or more per 1,00,000 per year. It is more prevalent
during rainy/ monsoon season. In developing countries, the disease occurs most commonly in
farmers and low-income people who live in areas with poor sanitation. In developed countries, it
occurs during floods and is a risk to sewage workers and those involved in outdoor activities in
warm and wet areas. Antarctica is the only place not affected by leptospirosis.
CAUSATIVE AGENT:
Leptospira interrogans is pathogenic to humans. It is a
Gram negative, long cork screw shaped obligate aerobe
spirochete, with periplasmic flagella. It resembles like a
question mark when viewed under dark field microscope
(not visible under ordinary microscope).
MODES OF TRANSMISSION:
Contact with urine from infected animals.
Contact through skin, mucosa or conjunctiva with water or soil contaminated with urine of
rodents (Rattus norvegicus) or diseased animals
(cattle, pig, dog, horse, wild animals etc..).
Ingestion of contaminated water.
Human to human transmission is rare.
Infected animals may continue to excrete the
bacteria into the environment continuously or
every once in a while, for a few months up to
several years.
Outbreaks of leptospirosis are usually caused by
exposure to contaminated water, such as floodwaters.
HIGH RISK GROUPS:
Farmers
Sewage workers
Pet shop workers
Slaughterhouse workers
Veterinarians and animal caretakers
Dairy farmers
Military personnel
Disaster relief workers
People involved in outdoor/recreational
activities such as swimming and outdoor sports.
People with chronic diseases and open skin wounds
PATHOPHYSIOLOGY:
SIGNS AND SYMPTOMS:
The symptoms of leptospirosis occur in two different phases, but in few individuals, symptoms are
not seen and first phase of symptoms resemble to that of flu and last for 3-7 days. First phase
symptoms include
Headache
Chills
Extreme muscle pain
Red-eye (conjunctival suffusion)
Extreme abdominal pain
Skin rash
Vomiting
Fatigue
Diarrhoea
Jaundice
When such symptoms occur, our immune system starts producing antibodies against the bacteria
Leptospira which help combat the bacteria present in the body. Therefore, around 90% of people
develop only mild symptoms or develop only first phase symptoms of Leptospirosis. A very few of
them experience severe symptoms that include:
Weil’s Disease
Hearing loss
Kidney failure accompanied by bleeding
Meningitis (infection causing inflammation in the membranes of the brain and spinal cord)
Pulmonary haemorrhage
Pneumonitis
Cardiac arrhythmias
The second phase of Leptospirosis is life-threatening. If it’s not treated early, it may develop serious
complications and may even lead to death.
DIAGNOSIS:
Leptospirosis has diverse symptoms like hepatitis, dengue fever, malaria, typhoid and other flu-
type illnesses. Therefore, specific tests are carried out for the proper
diagnosis of Leptospirosis.
It can be detected in cerebrospinal fluid and blood for the first 7-10 days
before it attacks the kidneys. In fresh urine, it is found after 7-10 days.
To determine the severity of complications, tests like CSF analysis,
Biliary tract ultrasonography, Complete blood cell (CBC) count, Chest
radiography, and Electrocardiography (ECG) are carried out.
TREATMENT:
PROPHYLAXIS:
PREVENTION:
WHO GUIDLINESS FOR PREVENTION OF LEPTOSPIROSIS:
WHY THERE IS LACK OF RECOGNITION OF LEPTOSPIROSIS?
Broad range of clinical manifestations.
May mimic other diseases (eg: dengue fever, viral fever etc…)
Diagnostic capabilities are not readily available.
Poor surveillance and reporting.
REFERENCES:
1. https://www.cdc.gov/leptospirosis/infection/index.html
2. https://www.who.int/topics/leptospirosis/en/
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