Introduction
Cholera is bacterial infection that is caused by Vibrio cholera sero group O1 and O139 mostly when people take water or consume food that has been contaminated with the bacteria. Vibriocholerae is a gram negative bacillus that usually requires culture of specimen for definitive diagnosis (Murugaiah 338). The cholera bacterium produces a toxin that induces secretion of water and electrolytes in the intestinal tract. Most people who get the infection experience acute diarrheal that can result into death within hours if left untreated. Nevertheless, majority of individuals who get exposed to Vibrio cholerae bacteria do not show any symptoms. These individuals can, however, act as sources of the bacteria as they pass excreta containing the bacteria into water or transmit the infection through unhygienic practices when handling food (Sanchez and Holmgren 391).
Symptoms of Cholera
Vibrio cholerae is a highly virulent bacterium that can infects all people, including adults and children, and can cause death after a very short duration. Three quarters of the people who contact the infection may not exhibit any symptoms, in spite of the bacteria being passed in their stool after 1-2 weeks following infection. These asymptomatic cases act as potential sources for further transmission of the infection in the population (Murugaiah 339).
In cases where cholera symptoms are exhibited, most of the people usually exhibit moderate symptoms whereas a significant number experience acute diarrhea, vomiting, and dehydration. These symptomatic cases have to receive rapid treatment because of the severity and fatality of the infection. The infection is particularly more fatal in individuals who are immunocompromised or malnourished. These groups of people carry an increased risk of death if they contact the bacteria (WHO para 2).
Haiti Republic
The Republic of Haiti is a Caribbean state found along the western part of Hispaniola, bordering the Dominican Republic. It has a population of almost 10 million people, making it among one of the most populated countries in the Caribbean community. In addition, the Republic of Haiti is ranked as the poorest state in America (Frerichs para 4). A significant number of the Haitians do not have access to basic healthcare, thus a majority of the people especially children are frequently affected by waterborne illnesses. Furthermore, a majority of the Haiti households do not have running water, while many people dwell in conditions that generally fall below standard sanitary conditions. According to WHO/UNICEF (2010) reports, access to sanitation and safe water is a problem, with estimates showing that it is just 17 percent of the people who lived under sanitary conditions in 2008 while only 12 percent had access to clean water (WHO/UNICEF para 4). This, according to Fraser (1813), reflects the high prevalence of diarrhea infections in Haiti and the high morbidity associated with these infections.
The country also experiences some of the greatest incidences of maternal and infant mortalities, the main parameters that measure the health system universally. Cholera epidemic was experienced in Haiti in the year 2010, the same year that a huge earthquake occurred in Haiti causing a lot of deaths and damages and displacing a lot of people. This cholera outbreak was considered an epidemic because no major outbreak of the infection had been witnessed in the country for a long time (Fraser 1813).
Epidemiology of Cholera in Haiti
Cholera is mostly endemic in many parts of Africa and Asia continents. Epidemics are mostly reported following calamities that lead to displacement of many people, or following conflicts that disrupt normal living conditions. It is estimated that the prevalence of cholera is largely underestimated globally since most cases are never reported. Annually, the World Health Organization receives reports of over 100,000 cases of cholera infections, with about 3,000 deaths (Sanchez and Holmgren 392). The disease is rarely reported in developed countries, but it is an important public health issue in underdeveloped countries (WHO para 3).
A major outbreak of cholera was reported first in Haiti, in the Caribbean region, in 2010 after a very long time. It is estimated that more than 500,000 people have been infected since the first case was reported in October 2010. More than 7,000 people have died of the disease, representing a case fatality rate of 7 percent (Frerichs para 4). It is still thought that these figures are not accurate since there was underreporting, particularly in rural areas where access to health facilities is not readily available and people die before reaching hospitals. This makes the Haitian cholera epidemic to be the largest cholera outbreak recorded in the recent history in the world. The disease was more severe in immunologically comprised people and children, mostly because their immune systems are not fully developed (WHO/UNICEF para 6).
Factors that Enhanced Cholera Epidemic
Vibrio Cholerae Strain
There are more than 200 sero groups of Vibrio cholerae that have been identified based on O antigen. The pathogenic bacterium is further classified into two strains, the EI Tor and classical. These two strains are also sub-classified into Ogawa and Inaba serotypes. Vibrio cholerae O1 is the most infective one, causing more than 98 percent of infections across the world (Murugaiah 338). The cholera outbreak in Haiti was attributed to Vibrio cholerae hybrid EI Tor strain. This strain is known to cause asymptomatic infections and survives for a long time in the environment. The bacterium also occurs in higher concentrations in stool even in the asymptomatic population. These factors make the bacterium to have high virulence; thus, it can spread easily and cause high fatalities. Cholera outbreaks can also occur easily especially when water systems and sanitary standards are disrupted, given that the bacterium can also be transmitted by asymptomatic carriers (Murugaiah 341).
Host Factors
Cholera can infect people of all ages, although children below five years are at a higher risk due to their naïve immune system. In addition, people who have a compromised immune system and those who are malnourished and have iron deficiency are also at a higher risk. A person’s vulnerability to cholera infection is also determined by his/her blood group, whereby it has been established that people with blood group AB have the highest resistance while those with blood O blood group are the most vulnerable (Murugaiah 341).
The bacterium is usually ingested following consumption of meals or drinking water that is contaminated, after which the bacterium passes through the acidic environment in the stomach into the upper part of the small intestine. The disease presents following colonization of the small intestines, after which pathogenicity is mainly perpetuated by the 2-subunit cholera toxin. The B subunit attaches Vibrio cholerae to the epithelial cell surface, eliciting immune reaction without causing toxic reactions. The release of the A subunit triggers a cellular biochemical reaction that results into secretion of fluids and electrolytes, subsequently causing diarrhea and dehydration (Sanchez and Holmgren 390)
Environment Factors
The environmental reservoirs play a significant role in the transmission of the bacterium from man-to-man. The aquatic environment in particular is essential for the maintenance of the infection cycle. Incidences of cholera outbreaks are increasingly being reported from warmer environmental temperature areas. Studies indicate that the susceptibility of the population, exposure to unsanitary conditions and the availability of an aquatic reservoir are significant variables that influence the epidemiology of cholera (WHO/UNICEF para 5). In Haiti, the huge earthquake that occurred in 2010 may have acted as an environmental trigger of cholera outbreaks as it led to destruction of the existing fragile infrastructure, disrupting the water supply system and aggravating the sanitary conditions. It is also thought that changes in climatic conditions may have triggered the growth of cholera bacteria since the bacterium can persist in the environment for a long time without causing infection. Therefore, climatic changes around Artibonite in Haiti may have stimulated growth of the bacteria, leading to the outbreaks (Frerichs para 8)
Vector for Vibrio cholerae
Cholera bacterium has been established to live on copepods for a length of time. Copepods inhabit Artibonite River, the area where the first cases of cholera were reported in Haiti, indicating that it may have been a potential source of the infection (Frerichs para 10).
Threat Assessment
In general, cholera infections are very rare in developed countries. Cholera does not pose a significant threat to the US owing to the highly developed water and sanitation systems. However, any possible cholera infection is most likely to arise among individuals who travel to endemic or epidemic areas or following consumption of foods from such areas (CDC para 4).
Medical Treatment Methods
Rehydration therapy
Treatment for cholera is a cheap and very effective treatment that usually involves oral rehydration to replace the lost fluids, although rehydration can also be done intravenously. The hydration fluids contain salts and sugars similar to the concentrations lost in stools of the infected patients, thus making up the electrolyte deficits and replacing the loss (Sanchez and Holmgren 393).
Antibiotic treatment
Antibiotic treatment is usually administered to individuals having a clinically significant cholera in order to shorten the disease and reduce diarrheal purging. Antibiotics are effective in curing the infection and they reduce the need to administer rehydration therapy, besides reducing the length of hospitalization. Antibiotics also are appropriate for minimizing transmission of the disease since they shorten shedding of the bacteria, thus reducing the risk to the public. Doxycycline and tetracycline are the most commonly used antibiotics, although it is necessary for sensitivity tests to be conducted in order to select the most effective drug (Murugaiah 2011). The use of antibiotics, however, needs constant assessment of antibiotic resistance to ensure the drugs match the antibiotic sensitivity of the strain.
Prevention measures
Preventive measures include administration of vaccines and improvement of sanitary conditions. Oral cholera vaccines have been employed as a preventive measure, especially for people traveling to endemic areas and where epidemics have been reported (WHO/UNICEF para 6).
The recommended hygienic measures include enhancement of water supply systems and sanitation. Provision of information to promote behavior change is advocated in areas that are impoverished. Some of the behavior changes include enlightening the population to ensure that water is safe by boiling or treating it, washing hands with safe water and soap, sanitary disposal of human waste, and cooking food well (Sanchez and Holmgren 394).
References
CDC. Cholera Prevention. 1992. Web.
Fraser, Barbara. “Haiti Still Gripped by Cholera as Selection Looms”. Lancet 376(2010): 1813-1814. Print.
Frerichs, Ralph. “Epilogue of the Origin of Cholera in Haiti”. UCLA. 2013. Web.
Murugaiah, Chandrika “The Burden of Cholera.” Critical Reviews in Microbiology 37.4 (2011): 337-348. Print.
Sanchez, JoaquĂn and Homlgren Jan. “Virulence Factors, Pathogenesis and Vaccine Protection in Cholera and ETEC Diarrhea”. Current Opinion Immunology 17(2005): 388-398. Print.
WHO. Cholera. 2012. Web.
WHO/UNICEF. “Progress on Sanitation and Drinking Water: 2010 Update”. Geneva: WHO/UNICEF. 2010. Web.