The earl symptoms of cholera

Cholera in India: A Detailed Research Report
Background
Cholera, caused by the bacterium Vibrio cholera, is an infection of the small intestine that is
spread through the oral-fecal route. With its origin from the Greek language, the word ‘cholera’
denotes bile. The earliest record of the disease is found in a 1642 European literature, named De
Medicina Indorum, written by the Dutch physician Jakob de Bondt. It most probably had its
origin in the Indian subcontinent since it was widely prevalent in these regions. Early outbreaks
in India are believed to have been the consequence of unhygienic living practices among the
masses as well as due to the presence of stagnant water bodies, both of which offer an ideal
environment for cholera to sustain and spread. The disease was then presumed to have spread by
trade routes to other countries likes Russia, Europe, North America and then to the rest of the
world ("Cholera: Background, Pathophysiology, Etiology" 2019).
Pathogen Responsible
The microorganism, which is responsible for causing the infection of cholera, named Vibrio
cholerae, is a Gram negative. Its name is derived from its vibrio or comma shape. However, not
all strains of the organism are pathogenic or harmful. The bacteria are facultative anaerobe i.e. it
can thrive both in the presence and in absence of oxygen but prefers the aerobic environment. Its
structural characteristics include a flagellum at one end of the cell as well as pili, made from pilin
proteins. The main habitat of the bacteria is in salt or brackish water bodies. When it ingested
with contaminated water, it starts showing the early symptoms of cholera like diarrhea and
vomiting. The symptoms may occur anytime between a few hours to a couple of days after
ingestion of the organism. V. cholera. It was first isolated by Italian anatomist Filippo Pacini in
1854, but due to the lack of proper documentation, much is not known about his contribution and
works. Almost after 30 years, Robert Koch, the celebrated microbiologist, started his
independent research on the organism and publicized his findings for the world.
Transmission
Transmission of cholera usually takes place via the fecal-oral route of contaminated food or
water, instigated by lack of hygiene and poor sanitation conditions. Most cases of in developed

countries are via transmission by food, while in the developing world it is contaminated water
that is assumed responsible. Among food items, shellfishes like oysters that are bred in
contaminated water or in sewage can be the carrier of the bacteria. This is because the oysters
feed on the planktons, which is a site of accumulation of the pathogens. In addition to that,
individuals who are infected with cholera have frequent diarrhea where watery stool is
discharged (colloquially referred to as "rice-water"). This stool, if allowed to get mixed with
water bodies, groundwater or drinking water supplies might spread the infection to healthy
people using the source of water for drinking, cooking, washing utensils etc. since V. cholerae
can exist outside the human body in water bodies, by itself or via interaction with
phytoplanktons, zooplanktons, or with abiotic and biotic detritus. Reports suggest that a single
incident of diarrhea can cause a one million-fold increase in numbers of bacteria in the
environment. However, it is rather rare for cholera to spread directly from affected individuals to
healthy people.
Nevertheless, selective pressures in aquatic environment can result in the reduction of the
virulence properties of V. cholera due to alteration in its transcriptional profiles. Studies indicate
that the culturability of V. cholerae descents by 90% within 24 hours of entering the water
source, and this loss in culturability often accompanies its loss in virulence. However, at times
non-pathogenic strains might also acquire virulence through the action of temperate
bacteriophage, a type of virus that uses bacterial organism as their hosts (Nelson et al. 2009).
Mechanism of Action
While most bacteria, after entry via the oral route, fail to survive in the acidic environment of the
stomach, few bacteria are capable of conserving their energy and stored nutrients while passing
through the stomach by stopping their production of proteins. After surviving in the low pH,
when the bacteria reach the small intestine, they propel themselves with the help of flagella
through the thick mucus layer that lines the small intestine and reach the intestinal walls to attach
themselves and thrive.
After reaching the intestinal wall, there is no longer the need for the bacteria to use its flagella.
The energy and resources conversed by shutting down the flagellin protein can then be used for
the synthesis of proteins to thrive in the small intestine. The virulence caused by the bacteria is
mainly due to the cholera toxin (CTX or CT), which is an oligomer made up of six protein

subunits, a single copy of the subunit A along with five copies of the subunit B, connected by a
disulfide bond. The toxin gains entry into taken into the cell via receptor-mediated endocytosis.
Once inside the cell, the disulfide bond is reduced, and the A1 subunit is freed to bind with a host
protein named ADP-ribosylation factor 6 (Arf6). Through a series of cascade, permanent
ribosylation of the alpha subunit of the heterotrimeric G protein occurs resulting in cAMP (cyclic
adenosine monophosphate) production, which further favors the secretion of water, sodium,
potassium, and bicarbonate ions into the lumen of the small intestine causing the loss of
electrolyte (Almagro-Moreno et al. 2015).
Symptoms
The major symptoms of cholera are diarrhea, which is characterized by watery stool, and
vomiting of clear fluids. These symptoms can start within a few hours to 2-5 days after ingestion
of the bacteria, depending upon the strain that has infected, general health of the patient, intensity
of infection etc. The diarrhea is colloquially described as "rice water" due to its similarity in
appearance and consistency to the leftover water from the rice boiling and might have a
characteristic fishy odor. An individual suffering from cholera, without any medication, may
produce 10 to 20 liters stool in a day. Incidents of mortality are very common among untreated
individual. Without proper medications, severe dehydration and electrolyte imbalances are the
major causes of death. Fever, though rare for cholera, might be a symptom for secondary
infection. Lethargy, sunken eyes, cold clammy skin, dry mouth, wrinkled hands, and feet are also
common among cholera patients. Due to dehydration and loss of electrolyte via vomiting and
feces, a significant drop in blood pressure, rise in peripheral pulse, muscle cramping, weakness,
altered consciousness, and seizures can be common in juvenile patients that can even lead to
comatose state. Cholera has been nicknamed as the "blue death" as skin of patients suffering
from the disease may turn bluish-gray from extreme loss of fluids and ions (Azman et al. 2013).
Diagnosis, Treatment and Prevention
A rapid dipstick test is the most popular method for the checking the presence of the bacteria.
Generally, serotypes O1 and O139 are the responsible for causing epidemics on a large scale. In
case of a pandemic, patient history should be collected before starting the diagnosis and basic
modes of treatment like administering electrolytes can be started even before receiving the
results of the diagnosis as the conditions are of the affected individuals are worsened rapidly and