A serovar or serotype is a group of microorganisms or viruses classified together based on their cell surface antigens. Serovars allow the epidemiologic classification of organisms to the sub-species level. A group of serovars with common antigens is called a serogroup. Serovars may be established based on virulence factors, lipopolysaccharides in Gram-negative bacteria, presence of an exotoxin (pertussis toxin in Bordetellapertussis, for example), plasmids, phages, or other characteristics which differentiate two members of the same species. Salmonella, for example, has over 4400 serovars: Salmonella entericaserovarTyphimurium, S. entericaserovarTyphi, and S. entericaserovar Dublin, to name a few. Vibriocholerae, which causes cholera, has 139 serotypes, based on cell antigens. Only two of them produce an enterotoxin and are pathogens: 0:1 and 0:139.Serotypes were discovered by the American microbiologist Rebecca Lancefield in 1933.
Vibriocholerae is a Gram-negative bacterium that produces cholera toxin, an enterotoxin, whose action on the mucosal epithelium lining of the small intestine is responsible for the disease's infamous characteristic, exhaustive diarrhea. In its most severe forms, cholera is one of the most rapidly fatal illnesses known, and a healthy person's blood pressure may drop to hypotensive levels within an hour of the onset of symptoms; infected patients may die within three hours if medical treatment is not provided. In a common scenario, the disease progresses from the first liquid stool to shock in 4 to 12 hours, with death following in 18 hours to several days, unless oral rehydration therapy is provided.
Snow conducted his classic study in 1854 when an epidemic of cholera developed in the Golden Square of London. He began his investigation by determining where in this area persons with cholera lived and worked. He then used this information to map the distribution of cases on what epidemiologists call a spot map.Because Snow believed that water was a source of infection for cholera, he marked the location of water pumps on his spot map, and then looked for a relationship between the distribution of cholera case households and the location of pumps. He noticed that more case households clustered around Pump A, the Broad Street pump, than around Pump B or C, and he concluded that the Broad Street pump was the most likely source of infection.
1816-1826 - First cholera pandemic: Previously restricted, the pandemic began in Bengal, and then spread across India by 1820. 10,000 British troops and countless Indians died during this pandemic. The cholera outbreak extended as far as China, Indonesia (where more than 100,000 people succumbed on the island of Java alone) and the Caspian Sea before receding. Deaths in India between 1817 and 1860 are estimated to have exceeded 15 million persons. Another 23 million died between 1865 and 1917. Russian deaths during a similar time period exceeded 2 million.1829-1851 - Second cholera pandemic reached Russia (see Cholera Riots), Hungary (about 100,000 deaths) and Germany in 1831, London (more than 55,000 persons died in the United Kingdom) and Paris in 1832. In London, the disease claimed 6,536 victims; in Paris, 20,000 succumbed (out of a population of 650,000) with about 100,000 deaths in all of France. The epidemic reached Quebec, Ontario and New York in the same year and the Pacific coast of North America by 1834. A two-year outbreak began in England and Wales in 1848 and claimed 52,000 lives.
1849 - Second major outbreak in Paris. In London, it was the worst outbreak in the city's history, claiming 14,137 lives, over twice as many as the 1832 outbreak. In 1849 cholera claimed 5,308 lives in the port city of Liverpool, England, and 1,834 in Hull, England. An outbreak in North America took the life of former U.S. President James K. Polk. Cholera spread throughout the Mississippi river system killing over 4,500 in St. Louis and over 3,000 in New Orleans as well as thousands in New York. In 1849 cholera was spread along the California and Oregon trail as hundreds died on their way to the California Gold Rush, Utah and Oregon. It is believed that over 150,000 Americans died during the two pandemics between 1832 and 1849. 1852-1860 - Third cholera pandemic mainly affected Russia, with over a million deaths. In 1853-4, London's epidemic claimed 10,738 lives. 1854 - Outbreak of cholera in Chicago took the lives of 5.5% of the population (about 3,500 people). The Soho outbreak in London ended after removal of the handle of the Broad Street pump by a committee instigated to action by John Snow. 1863-1875 - Fourth cholera pandemic spread mostly in Europe and Africa. At least 30,000 of the 90,000 Mecca pilgrims fell victim to the disease. Cholera claimed 90,000 lives in Russia in 1866. The epidemic of cholera that spread with the Austro-Prussian War (1866) is estimated to have claimed 165,000 lives in the Austrian Empire. Hungary and Belgium both lost 30,000 people and in the Netherlands 20,000 perished. In 1867, Italy lost 113,000 lives. 1866 - Outbreak in North America. It killed some 50,000 Americans. In London, a localized epidemic in the East End claimed 5,596 lives just as London was completing its major sewage and water treatment systems--the East End was not quite complete. William Farr, using the work of John Snow et al. as to contaminated drinking water being the likely source of the disease, was able to relatively quickly identify the East London Water Company as the source of the contaminated water. Quick action prevented further deaths. Also a minor outbreak at Ystalyfera in South Wales. Caused by the local water works using contaminated canal water, it was mainly its workers and their families who suffered, 119 died. In the same year more than 21,000 people died in Amsterdam, The Netherlands. 1881-1896 - Fifth cholera pandemic; According to Dr A. J. Wall, the 1883-1887 epidemic cost 250,000 lives in Europe and at least 50,000 in Americas. Cholera claimed 267,890 lives in Russia (1892); 120,000 in Spain; 90,000 in Japan and 60,000 in Persia. In Egypt cholera claimed more that 58,000 lives. The 1892 outbreak in Hamburg, Germany killed 8,600 people. Although generally held responsible for the virulence of the epidemic, the city government went largely unchanged. This was the last serious European cholera outbreak. 1899-1923 - Sixth cholera pandemic had little effect in Europe because of advances in public health, but major Russian cities (more than 500,000 people dying of cholera during the first quarter of the 20th century) and the Ottoman Empire were particularly hard hit by cholera deaths. The 1902-1904 cholera epidemic claimed 200,222 lives in the Philippines. The sixth pandemic killed more than 800,000 in India. The last outbreak in the United States was in 1910-1911 when the SMS Moltke brought infected people to New York City. Vigilant health authorities isolated the infected on Swinburne Island. Eleven people died, including a health care worker on Swinburne Island. 1961-1970s - Seventh cholera pandemic began in Indonesia, called El Tor after the strain, and reached Bangladesh in 1963, India in 1964, and the USSR in 1966. From North Africa it spread into Italy by 1973. In the late 1970s, there were small outbreaks in Japan and in the South Pacific. There were also many reports of a cholera outbreak near Baku in 1972, but information about it was suppressed in the USSR. January 1991 to September 1994 - Outbreak in South America, apparently initiated when a ship discharged ballast water. Beginning in Peru there were 1.04 million identified cases and almost 10,000 deaths. The causative agent was an O1, El Tor strain, with small differences from the seventh pandemic strain. In 1992 a new strain appeared in Asia, a non-O1, (NAG) named O139 Bengal. It was first identified in Tamil Nadu, India and for a while displaced El Tor in southern Asia before decreasing in prevalence from 1995 to around 10% of all cases. It is considered to be an intermediate between El Tor and the classic strain and occurs in a new serogroup. There is evidence of the emergence of wide-spectrum resistance to drugs such as trimethoprim, sulfamethoxazole and streptomycin.
Period of communicability: The interval during which a person or animal that has an infection is a potential source of infection.Communication period: The time in the natural history of an infection during which transmission may take place.
Risk: Once the bacterium is ingested, it must survive the stomach acids on its way to the intestine. The very young and the elderly are most severely affected because they often lack stomach acids strong enough to provide an adequate defense. Similarly, individuals taking antacids are at increased risk. People living in areas commonly affected by cholera may acquire some immunity and so in these areas it is often the very young with no prior exposure that are most severely affected.
Slum: a very poor and crowded area, mainly city.
Writer Susan Sontag wrote that cholera was more feared than some other deadly diseases because it dehumanized the victim. Diarrhea and dehydration were so severe that the victim could literally shrink into a wizened caricature of his or her former self before death. Other symptoms include nosebleed, rapid pulse, dry skin, tiredness, abdominal cramps, nausea, leg cramps, and vomiting.
Wrinkle: 1 a small line in the skin caused by old age 2 a small line or fold in cloth
Mode of transmission: the way or ways in which a disease is transmitted. Can be direct (person-to-person) or indirect (common vehicle or vector).
Complications: New medical problems that arise while treating existing ones.If not treated immediately cholera could become fatal. In the most severe cases, the quick loss of huge amounts of body fluids and electrolytes could lead to death within two to three hours. In less severe cases if not treated immediately people may die of shock and dehydration 18 to 48 hours after the first symptoms of cholera appear.Shock and severe dehydration are the most devastating complications of cholera there are other problems that could occur:Low blood sugar. It is a common complication for children. This happens when the body’s main energy source is extremely low. When cholera is sever people become too ill to eat they don’t get glucose from food and the body is unable to carry out normal glucose absorption. This could lead to low blood sugar levels, which can cause seizures, unconsciousness and even death. Low potassium levels. People who have cholera lose large amounts of minerals, including potassium in their stools. Potassium levels that are low interfere with the heart and nerve function and are life-threatening. This is very serious in people whose potassium levels have already been depleted by malnutrition.Kidney renal failure. Excess amounts of fluid and waste build up in your body when the kidney loses its filtering ability. This is a potentially life-threatening condition. Kidney failure often accompanies shock in people with cholera.
The sterilization process eliminates all microorganisms (bacteria, viruses, fungi, and parasites), including bacterial endospores. Sterilization is recommended for instruments and for other items that will come in contact with the bloodstream or tissues under the skin.Sewage: Human body wastes and the wastes from toilets and otherreceptacles intended to receive or retain body wastes.
Vaccine: A medication that stimulates the production of antibodies to protect against a specific disease. ORVaccine: A substance that protects a body against a disease by causing the body’s immune system to produce antibodies.
electrolyte SPECIALIZED a substance, usually a liquid, which electricity can go through or which breaks into its parts when electricity goes through it
Antibiotic: A substance, similar to those produced by certain fungi for destroying bacteria, which kills or inhibits the growth of microorganisms. An antibiotic is used to combat disease and infection.
FCHV: Female Community Health VolunteerMCHC: Mother and Child Health CareMCHW: Maternal and Child Health WorkerVHW: Village Health Worker
CHOLERA Presented By: Kamal Bahadur Budha
EPIDEMIOLOGY OF CHOLERA Introduction Magnitude of the Program Agent, Host and Environment Sign and symptoms Complications. Prevention and Control Program Status National Policy and Strategies References2
INTRODUCTION Cholera is an infection in the small intestine caused by the bacterium Vibrio cholerae. The word cholera is from Greek: kholera from kholē "bile". The main symptoms are watery diarrhea and vomiting. Transmission occurs primarily by drinking water or eating food that has been contaminated by the feces (waste product ).3
Contd. … Vibrio cholerae is a Gram-negative bacterium that produces cholera toxin, Vibrio cholerae, which causes cholera, has 139 serotypes, based on cell antigens. Only two of them produce an enterotoxin and are pathogens: 0:1 and 0:139 Cholera endemic and epidemic today in developing countries, some cases also found in developed countries. Cholera became one of the most widespread and deadly4 diseases.
EPIDEMIOLOGY OF CHOLERA Introduction Magnitude of the Program Agent, Host and Environment Sign and symptoms Complications. Prevention and Control Program Status National Policy and Strategies References5
OCCURRENCE: Cholera likely has its origins in the Indian Subcontinent; it has been prevalent in the Ganges delta since ancient times. The disease first spread by trade routes (land and sea) to Russia in 1817, then to the rest of Europe, and from Europe to North America. Seven cholera pandemics have occurred in the past 200 years, with the seventh originating in Indonesia in 1961.7
OCCURRENCE: The first cholera pandemic occurred in the Bengal region of India starting in 1817 through 1824. The disease dispersed from India to Southeast Asia, China, Japan, the Middle East, and southern Russia. The second pandemic lasted from 1827 to 1835 and affected the United States and Europe. It killed 150,000 Americans during the second pandemic. The third pandemic erupted in 1839, persisted until 1856, extended to North Africa, and reached South America, for8 the first time specifically infringing upon Brazil.
OCCURRENCE: In Russia alone, between 1847 and 1851, more than one million people perished of the disease. Cholera hit the sub-Saharan African region during the fourth pandemic from 1863 to 1875. The fifth pandemic raged from 1881–1896. sixth pandemics raged from 1899-1923. Between 1900 and 1920, perhaps 8 million people died of cholera in India. These epidemics were less fatal due to a greater9 understanding of the cholera bacteria.
OCCURRENCE: Egypt, the Arabian peninsula, Persia, India, and the Philippines were hit hardest during these epidemics, while other areas, like Germany in 1892 and Nepalese from 1910–1911, experienced severe outbreaks. The final pandemic originated in 1961 in Indonesia and is marked by the emergence of a new strain, nicknamed El Tor. which still persists today in developing countries. cholera became one of the most widespread and deadly diseases of the 19th century.10
SIZE OF THE PROBLEM GLOBALLY: 140 000 – 290 000 cases were reported between 1997- 1998. In 1999, global incidence was about 254 000 , and Africa alone accounted for about 81% of the global total number of cases. In 2000, multiple outbreaks were reported in populations in various islands of Oceania .11
Cholera affects an estimated 3–5 million people worldwide, & causes 100,000–130,000 deaths a year as of 2010. This occurs mainly in the developing world. In the early 1980s, death rates are believed to have been greater than 3 million a year. Cholera remains both epidemic and endemic in many areas of the world.12
Nepalese origin of cholera epidemic in Haiti. Cholera appeared in Haiti in October 2010 for the first time in recorded history. Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor. The isolates were obtained from 30 July to 1 November 2010 from five different districts in Nepal. 24 cases of V. cholerae isolates from Nepal16
Doti cholera outbreak under control A total of 14 persons had lost their lives due to the epidemic from June 13 to July 1 in the district. District Health Office informed that it has treated more than 700 cholera patients till now. Cholera was found in people from Doti’s Dipayal Silgadi municipality along with Kalena, Bagalek, Khatiwada, Gajari, Kadamandau, Sanagaun, Basudev, Durgamandau, Barwata and Gajunda17 VDCs.
EPIDEMIOLOGY OF CHOLERA Introduction Magnitude of the Program Agent, Host and Environment Sign and symptoms Complications. Prevention and Control Program Status National Policy and Strategies References18
AGENT FACTORS Agent: Vibrio cholerae Has over 150 identified serotypes based on O-antigen Only O1 and O139 are toxigenic and cause Cholera disease (Water-borne illness) Source of infection: case of Cholera by Fecal-oral transmission Infective materials: secretion of the Intestine cases.19 .
Period of CommunicabilityDuring acute stageA few days after recoveryBy end of week, 70% of patients non-infectiousBy end of third week, 98% non-infectious 20
HOST FACTORS 1. Age: Children: 10x more susceptible than adults, And Elderly also higher susceptible. 2. Sex: Equal in both male and female. 3. Immunity: Less immune higher risk. 4. People with low gastric acid levels 5. Blood types O>> B > A > AB21
ENVIRONMENTAL FACTORS at risk areas include peri urban slums, refugee camps where clean water and sanitation are not met Consequences of a disaster Lack of education, poor quality of life22
EPIDEMIOLOGY OF CHOLERA Introduction Magnitude of the Program Agent, Host and Environment Sign and symptoms Complications. Prevention and Control Program Status National Policy and Strategies References24
SIGNS AND SYMPTOMs The primary symptoms of cholera are profuse, painless diarrhea and vomiting of clear fluid. The diarrhea is frequently described as "rice water" in nature and may have a fishy odor. An untreated person with cholera may produce 10 to 20 litres of diarrhea a day with fatal results. patients skin turning a bluish-gray hue from extreme loss of fluids.25
If the severe diarrhea is not treated with intravenous rehydration, it can result in life- threatening dehydration and electrolyte imbalances. The typical symptoms of dehydration include low blood pressure, poor skin turgor (wrinkled hands), sunken eyes, and a rapid pulse.27
A person with severe dehydration due to cholera - note the sunken eyes and decreased skin turgor28 which produces wrinkled hands and skin
MODE OF TRANSMISSION A. Primary ingestion of water (contaminated with faeces) OR B. Ingestion of food contaminated by dirty water, faeces, soiled hands or flies. OR C. The disease transmitted from one person to another person in over crowded and unhygienic conditions.29
INCUBATION PERIOD Ranges from a few hours to 5 days. Universal I/P is 5 days. Shorter incubation period: High gastric pH (from use of antacids) Consumption of high dosage of cholera30
EPIDEMIOLOGY OF CHOLERA Introduction Magnitude of the Program Agent, Host and Environment Sign and symptoms Complications Prevention and Control Program Status National Policy and Strategies References31
COMPLICATIONS The degree and duration of fluid and electrolyte loss determines the medical consequences of cholera. For example, renal failure may stem from the reduced fluid flow through the kidneys; low blood sugar (hypoglycemia) may result in seizures or coma, especially in the young; or lowered potassium levels may trigger serious cardiac complications32
EPIDEMIOLOGY OF CHOLERA Introduction Magnitude of the Program Agent, Host and Environment Sign and symptoms Complications Prevention and Control Program Status National Policy and Strategies References33
Control and prevention Sterilization: Proper disposal and treatment of infected fecal waste water produced by cholera victims and all contaminated materials (e.g. clothing, bedding, etc.) are essential. Sewage: antibacterial treatment of general sewage by chlorine, ozone, ultraviolet light or other. Source: to decontaminate the water (boiling, chlorination etc.) for possible use.34
CONT. .. Water purification: All water used for drinking, washing, or cooking should be sterilized by either boiling, chlorination, ozone water treatment, ultraviolet light sterilization. Surveillance and prompt reporting allow for containing cholera epidemics rapidly. practice of folding a sari (a long fabric garment) multiple times to create a simple filter for drinking water.35
VACCINE A number of safe and effective oral vaccine for cholera are available. Dukoral, inactivated whole cell vaccine, has an overall efficacy of about 52% during the first year after being given and 62% in the second year, with minimal side effects. It is available in over 60 countries. One injectable vaccine was found to be effective for two to three years. Work is under way to investigate the role of mass vaccination. WHO recommends immunization of high risk groups, such as37 children and people with HIV, in countries.
Treatment Continued eating speeds the recovery of normal intestinal function. The World Health Organization recommends this generally for cases of diarrhea no matter what the underlying cause. A CDC training manual specifically for cholera states: “Continue to breastfeed your baby if the baby has watery diarrhea, even when traveling to get treatment. Adults and older children should38 continue to eat frequently.”
Fluids: In most cases, cholera can be successfully treated with oral rehydration therapy (ORT), which is highly effective, safe, and simple to administer. Electrolytes: As there frequently is initially acidosis, the potassium level may be normal, even though large losses have occurred.39
Cholera 40 patient being treated by medical staff in 1992
Antibiotic treatments for one to three days shorten the course of the disease and reduce the severity of the symptoms. Doxycycline is typically used first line, Other antibiotics proven to be effective include cotrimoxazole, erythromycin, tetracycline, chloramphenicol, and furazolidone.41
EPIDEMIOLOGY OF CHOLERA Introduction Magnitude of the Program Agent, Host and Environment Sign and symptoms Complications Prevention and Control Program Status National Policy and Strategies References42
DIARRHOEA CONTROL PROGRAM IN NATIONAL CONTEXT CONTROL OF DIARRHOEAL DISEASE (CDD) the CB-IMCI programme was expanded up to community level. Although the incidence of diarrhoea has increased significantly in this fiscal year but the proportion of severe dehydration cases was decreased at the last year. Almost half of the diarrhoeal cases (50%) were treated by the Female Community Health Volunteers (FCHVs).43
STRATEGY FOR DIARRHOEA CONTROL Training to all health workers on CB‐IMCI including zinc treatment for diarrhoea; Nutritional supplementation, enrichment, nutrition education and Rehabilitation Environmental sanitation School Health Program Raise public awareness; and promote specific prevention measure through communication. increase access to the Zinc tablets through CHW44 (FCHVs, VHWs & MCHWs).
Community Based Integrated Management of Childhood Illness (CB-IMCI) Program CB-IMCI programme intensely focuses on management of Diarrhoeal diseases among the under five year’s children. Standard case management of diarrhoea with Oral Rehydration therapy and Zinc tablet has been provided in the community level. All health facilities and community health volunteers at community level will serve as the primary health care providers in the45 treatment of Diarrhoea
Prevention and control of cholera outbreaks: WHO policy and recommendations The main tools for cholera control are: proper and timely case management in cholera treatment centres; specific training for proper case management, including avoidance of nosocomial infections; sufficient pre-positioned medical supplies for case management (e.g. diarrhoeal disease kits); improved access to water, effective sanitation, proper waste management and vector control; enhanced hygiene and food safety practices;46 improved communication and public information.
EPIDEMIOLOGY OF CHOLERA Introduction Magnitude of the Program Agent, Host and Environment Sign and symptoms Complications. Prevention and Control Program Status National Policy and Strategies References47