The bacterium Vibrio cholerae is the source of the acute secretory diarrheal disease known as cholera. The facultative, gram-negative, comma-shaped, oxidase-positive rod Vibrio cholerae is common in underdeveloped nations. Two serotypes have been found to be the cause of epidemics: O139, which mostly causes intermittent outbreaks in Asia, and O1, which is the cause of all current outbreaks. The two are not different etiologically. Poorly sterilized water and food—typically shellfish—are two sources of V. cholerae.
The bacteria are transmitted through the fecal-oral route, are endemic to regions with poor food and water hygiene, and require a high dose to become pathogenic. Proton-pump inhibitor (PPI) and antihistamine use, type 0 blood, poor sanitation, overcrowding, previous vagotomy, and Helicobacter pylori infection are among the factors that promote vulnerability.
This gastrointestinal illness is marked by high-volume fluid loss and electrolyte imbalances that can lead to hypovolemic shock and, eventually, death. The infection can vary in severity and is spread by the fecal-oral route. Replacing lost fluids and electrolytes as soon as possible is crucial.
Epidemiology
Around 4 million cases of cholera are reported globally each year, and the illness is responsible for over 140,000 fatalities. Almost 1.8 million people globally get their drinking water from sources that are tainted with human waste, which could serve as a haven for the cholera germs. Epidemics are known to happen, especially in underdeveloped nations where standards for water purification and sanitation may be lacking. As of right now, cholera is thought to be endemic in about 50 countries, primarily in Asia and Africa.
Depending on when the region’s rainy season occurs, the incidence is linked to a seasonal distribution. However, in other parts of the world, such as South and Central America, epidemics can be more widespread. Epidemic proliferation has been reported to occur when a species is introduced to an area where sanitation and health services have collapsed.
Previous exposure to the organism can influence host vulnerability and even induce immunity, albeit this depends on the biotype and serotype of the previously encountered organism. It takes a high dose of inoculation to infect a healthy adult because it is a labile acid bacterium. This may help to explain why the threshold required for the bacteria to cause infection can be lowered in situations of reduced gastric acidity, such as achlorhydria. It’s interesting to note that blood type O has also been linked to a higher risk of infection. It is yet unclear how this heightened vulnerability to illness is caused.
Proton pump inhibitor and antihistamine use may raise the patient’s risk of infection and increase the likelihood of more severe symptoms. The duodenum is usually the source of the fluid losses, while the colon is not affected by the toxin. Most of the time, neutrophils are not seen in fecal collections because enterotoxin is non-invasive and only has a localized effect.
Signs and symptoms
The symptoms of cholera can vary, ranging from diarrhea to lack of symptoms. Vomiting, upset stomach, and diarrhea are typical symptoms. Because severe cholera causes a significant and quick loss of fluid and electrolytes, it can be clinically recognized from other diarrheal disorders. The feces are frequently described as having a consistency similar to “rice water,” and they may also contain mucus and bile. A child’s production can be as high as 20 cc/kg/hr, while an adult’s can be as high as one liter per hour.
The ensuing hypovolemia causes the typical signs and symptoms of fluid loss, such as chilly skin, reduced skin turgor, and dry mouth mucosa. Lactic acidosis, which is brought on by inadequate bodily tissue perfusion, can lead to hyperventilation and Kussmaul breathing. Additionally, generalized muscular weakness and cramping may be caused by electrolyte imbalances such as hypokalemia and hypocalcemia.
Diagnosis
Clinical suspicion may serve as the basis for the diagnosis of cholera. Diagnosis may be made solely based on visit to an infected location and the characteristic high-volume diarrhea. As a result, before starting treatment, laboratory testing is frequently not necessary. However, the isolation and culture of V. cholerae from stool isolates can verify the diagnosis. Selective high-pH media can be used to improve culture by inhibiting the growth of intestinal microflora and promoting the growth of V. cholerae.
Similarly, quick tests can be used to determine whether stool samples contain the O1 or O130 antigen. Rapid identification or visualization of the organism can be achieved with readily available techniques such as darkfield microscopy of the feces and dipsticks.
Treatment and Management
Prompt fluid resuscitation based on the degree of volume loss is the cornerstone of cholera treatment. Oral rehydration solution should be administered if body weight loss is predicted to be between 5% and 10%. Oral rehydration solutions based on rice have been demonstrated in clinical trials to reduce the length of diarrhea and the volume of feces lost. One liter of water combined with six tablespoons of sugar and half a teaspoon of salt can be used as a remedy in an emergency.
Intravenous fluids should be given to patients who have lost more than 10% of their body weight or who are in hypovolemic shock. Throughout the first three hours, 100 mL/kg of lactated ringers should be given. Fluids administered promptly can lower the fatality rate from over 10% to less than 0.5% in cases of severe cholera.
Antibiotic therapy might start as soon as the patient reaches the proper volume condition. By far the most widely utilized class is tetracyclines. The length of the disease can be shortened with a single 300 mg dose of doxycycline or 500 mg of tetracycline every 6 hours for two days. Alternative treatments, however, include macrolides like azithromycin and erythromycin or fluoroquinolones like ciprofloxacin, as resistance is frequent in some places.
Prognosis
There have been reports of mortality rates exceeding 50% in the absence of fluid and hydration. Pregnant ladies, elderly people, and children have increased death rates. Overall, lower death rates can be attributed to increased access to healthcare, more hygienic conditions, and increased educational opportunities.
Rotavirus infection, Salmonellosis, Shigellosis, Escherichia coli infection, and typhoid fever are examples of differential diagnoses. Dehydration, acute tubular necrosis, renal failure, severe hypotension, and death are the consequences.
Preventive Actions
It is best to boil water before drinking it. Given how frequently food might become contaminated, it is advisable to wash all fruits and meals with clean water. Hand washing is crucial and should be enhanced as part of good personal hygiene. To stop the spread of cholera, numerous nations have now put in place systems for timely reporting and surveillance.
When an outbreak occurs, a group of nurses and other medical professionals typically send out a warning so that a coordinated response may be started. Controlling environmental factors and altering human behavior are essential to preventing outbreaks. The key is education.
The pharmacist should advise visitors to tropical regions where cholera epidemics have happened to practice basic hygiene, such as washing food in clean water and consuming only bottled water. There are vaccines available, but there is little chance that a traveler will contract cholera. The cholera vaccine guidelines and who should not receive it should be known to the pharmacist.
Compared to earlier times, cholera’s morbidity and fatality rate are significantly lower today. The main explanation is that healthcare professionals understand how important it is to stay hydrated and replace lost electrolytes. The death rate without water was about 50% in the past, but it is currently less than 5%. Rehydrating as soon as symptoms appear is crucial to the course of treatment.
Health Education
The patient and family in endemic areas should get education on better sanitation, boiling water, and personal hygiene. Improving public health initiatives like appropriate sewage disposal and providing clean drinking water are essential to preventing cholera. A large portion of the tainted water is used to fertilize crops and wash fruits and vegetables, which perpetuates the cholera epidemic. Food handlers need to receive training on good handwashing technique and personal hygiene.
Sufficient sanitation and water filtration are essential components of the strategy to prevent sickness among tourists. They ought to be made aware of the dangers of eating raw fruits and vegetables and undercooked seafood. While tap water should be avoided, it can be boiled or filtered to lower the possibility of spreading V. cholerae.
Adults between the ages of 18 and 64 who visit a region where cholera is still spreading are authorized to get the live, attenuated oral cholera vaccine in the United States. Ten days prior to travel to a location where the disease is endemic, a single dose is given. The vaccine’s effectiveness may be affected by systemic antibiotic treatment, thus it should be given apart from that. It was shown that, three months after immunization, the efficacy was 80%. There are three killed whole-cell oral vaccinations that can be used globally.
Since cholera typically spreads through epidemics, an interdisciplinary team is most suited to handle cases. Numerous protocols have been developed to control cholera epidemics. Rehydration efforts should be vigorous and proactive during cholera outbreaks. If this infectious disease is not identified in time, it might quickly result in death. It is essential to identify the afflicted patient as soon as possible because timely treatment will stop more infections.