Cholera

Cholera (cholera asiatica) - infectious intestinal infectious disease accompanied General intoxication, profuse diarrhea, vomiting, convulsions, hypothermia. Cholera belongs to a group of especially dangerous (quarantine) infections. In the past cholera have assumed the character of devastating epidemics. In Asia (India, Pakistan, and others) and currently cholera is endemic. In recent years, outbreaks of cholera caused by Vibrio El tor, there were outside the endemic foci (Europe, Africa).
Etiology. The disease is caused by Vibrio cholerae, slightly curved wand (in the form of a comma), has one flagellum, mobile. There are pathogens classic cholera and biotype El tor. Vibrio cholerae little resistant to the external environment, but well preserved at low temperatures and in the water. Under the influence of disinfectants (bleach, the bleach, the Lysol), hydrochloric acid at a dilution of 1 : 1000 vibrios quickly die.
Epidemiology. The source of infection is a sick person, reconvalescent and vibrionaceae. From the number of patients is especially dangerous patients light and erased (atypical) form of cholera. Vibrionaceae and sick mild form of the disease can rapidly dissipate infection and does not always duly identified (for example, cholera caused by biotype El tor). The infection is transmitted through water, food products (vegetables, fruits, milk, jellies and other), household items and care contaminated with secretions of patients and vibrionaceae. Accordingly, it is possible to allocate the leading type of epidemic process - water, food, etc. In the spread of cholera, can participate flies.
Pathogenesis. The pathogen enters the body of a person only through his mouth. A significant number of vibrios dies under the action of hydrochloric acid gastric juice. Having penetrated into the small intestine, vibrios intensive breeding and partly die, releasing toxins. With cholera no vibriones and toxemia. One of the toxic factors, "choleragen," is specific and determines the development of dehydrating diarrhea, General intoxication. Under the influence of toxic products of V. cholerae is impaired water-salt metabolism, increases the permeability of the blood vessels of the intestine.

Cholera (cholera asiatica) - an acute infectious disease characterized by the defeat of the small intestine, intoxication and dehydration.
Developed in the early 20th century, the system of anti-epidemic measures helped to limit the spread of cholera. Since 1926 diseases were registered mainly in India and Pakistan, although in some years was noted in Iraq, Indonesia, Iran, Afghanistan and other Asian countries.
In the USSR cholera eliminated in 1925-1926,
Almost all known until 1960 cholera epidemics were caused classic by Vibrio cholerae. Since 1961 there is a tendency to growth of diseases caused by Vibrio El tor. Classical strains of V. cholerae emit mainly in old endemic foci - Pakistan, Indonesia and Burma. In some places of India Vibrio El tor has also shown a tendency to exclude classical strains. Most of cholera epidemics that occurred in 1961 -1965, previously free of the infection countries, was caused by Vibrio El tor.

Etiology
The causative agent of cholera is Vibrio comma [(Schroeter) Winslow et al. (synonym: Vibrio cholerae Neisser, 1893; Kommabacillus Koch, 1883-1884; Spirillum cholerae asiaticae Zopf, 1885)]. Vibrio comma belongs to the genus Vibrio Muller (1773) from the family Spirillaceae Migula (1894). Described Koch (K. Koch)]. Vibrio comma is a slightly curved stick with rounded ends, much of variable size: 1.5 to 4 microns in length and 0.2-0.4 microns in width. There are vibrios singly or s-shaped pairs, sometimes in the content of the intestine in the form of short chains or spirals (Fig. 1). It is easy to make the involutionary shaped, gram-negative, do not form spores, mobile, aerobic. The optimum growth temperature 37 C; the range from 16 to 42 degrees. The optimum pH=7,0-8,0; the range of pH 6,4-9,6.
On agar in a day form of round, 1-2 mm in diameter, slightly convex, transparent, blue colony with a smooth or fine shiny surface and smooth edges, oily consistency, easy emulsifiable; later their surface is covered with small knots - secondary (subsidiary) colonies.
A few hours after sowing form a film on the broth and on peptone water; moderately muddy the environment.
Partially thin collapsed serum Loeffler.
I belong to the group of vibrios (see) according to the classification of Heiberg; split up to acid mannose and sucrose and not fermented to arabinose, in two weeks can form acid in the presence of lactose.
Slowly diluting gelatin. Oxidized starch. Do not give responses of Fogasa - Proskauer. Form ammonia, indole and hydrogen sulfide (slowly). Restore methylene blue and nitrates. Cause positive nitroso-indolului reaction. Urea is not decompose. Not usually are lysed RBCs sheep and goats. Soluble toxin do not form.
On specificity Of antigen there are three types: "Inaba", "Ogawa and Hikojima". Cause the formation of bacteriolytical contributing to the phenomenon of Pfeifer-Isaeva. Unstable: quickly perish in the drying and heating to 55 degrees, the impact of 0.5% of phenol and small amounts of chlorine.
Dried linen survive within 1-3 days. Stored in clean water for up to 30 days and more, but in waste die within days.
Another causative agent of cholera is described by Goslikon (F. Gotschlich) in 1906 Vibrio El Tor, which currently many researchers regard as a strain or biotype of Vibrio comma. Distinctive features of Vibrio El Tor are: 1) low sensitivity to bacteriophage IV type Mukerji or phage type; 2) the ability to agglutinate chicken erythrocytes; 3) an increase of alkaline Martin agar or Hottinger in the presence polimiksina M or (50 u/ml environment); 4) agglutination On-serum 0.3% solution carbonate of soda; 5) formation of acetylaminophenol (positive reaction of Fogasa-Proskauer).
Due to the large variability of the properties of vibrios differential diagnosis Vibrio comma and Vibrio El Tor should be carried out by a combination of traits.


Epidemiology
Cholera belongs to the group anthroponotic intestinal infections, in which the only source of infection is a sick person and vibrionaceae. The sources of infection in comparative epidemiological risk can be placed in the following descending order: the patient alkidnoj form - gastroenteriticheskaya - gastritises - vibrionaceae reconvalescent - healthy vibrionaceae. When mapping these sources of infection can be mentioned the decrease of intensity of excretion infectious agent from the body with the increasing extensiveness of infection. Patient alkidnoj form, despite the release of a large amount of V. cholerae, is usually epidemiological danger for a limited circle of persons (mostly directly caring of him), while vibrionaceae can rapidly dissipate infection and put it on the big distances from the primary tumor.
In maintaining the continuity of the epidemic process has to be continued along with the media play an important role patients with mild and erased forms of cholera, is not always timely detected.
The ratio expressed, erased forms of the disease and vibrionaceae, according to L. Century gromashevskaya, is 7:3:2.
As specifies Felsenfeld (O. Felsenfeld), typical forms of cholera make up only 5-10% of all diseases.
In the focuses of cholera is determined by a significant number of vibrionaceae. According to various authors, the number of vibrionaceae among persons having contact with patients, ranging from 3.6%to 12%.
During the outbreak of cholera in the Philippines frequency of carriage for the family members of patients was 18%, and in relation to the total population is 2% .
As observations show that a significant part of the media with detailed clinical examination can identify the symptoms be benign disease. Fibrinoliticescuu in healthy usually short (in the vast majority of healthy carriers of the duration of allocation of V. cholerae does not exceed 10-14 days). The convalescents the pathogen can be allocated to i!0 days. In some cases, perhaps longer fibrinoliticescuu (up to 3 years and more).
After bringing the cholera on a particular territory of the first cases of the disease usually occurs in the result of household contact (dirty hands, the affected linen, kitchenware and other household items). The spread of cholera, can participate flies.
The causative agent of cholera can be transmitted through food and water. Named path and factors usually act socetannoe, but in some cases it is impossible to identify the leading type of epidemic process (water, food and other).
Foodborne outbreaks most part occur among the limited circle of persons who are infected products. Describe diseases related to drinking infected milk, water dishes, fish and other food products.
During the outbreak of cholera in the Philippines in 1961 by a factor of transmission of the pathogen was raw shrimp caught near the place of the descent of sewage waters.
Waterborne outbreaks of cholera in the short term cover a significant mass of the population using water from contaminated water source. The younger age group it affects less. The scale of the outbreak is wide use of water contaminated water source and intensity of pollution his uncleanness.
Large epidemics of cholera in the past experienced with contamination of tap water. Known cholera outbreaks associated with drinking contaminated water from open reservoirs, wells, domestic water in barrels and so on streamlining the supply leads to a sharp decrease morbidity.
When cholera outbreaks associated with factors of contact-household transmission, epidemic process has been slower.
The spread of cholera promote intensive migration processes associated with wars, social disasters.
Cholera are observed in different age groups, however, the most affected is the active part of the population (aged 20-40 years). In endemic cholera areas dominated by diseases among children and the elderly.
In countries with a temperate climate characterized summer-autumn rises in the incidence of cholera associated with the activation of ways and factors of transmission (drinking large quantities of water, fruit and vegetables in their raw form, bathing, flies and others).