Clinical presentation and initial manifestations
The development of the disease begins after an incubation period that varies widely: from a few hours (minimum 2 hours) to 6 days. The infection is characterized by an acute onset.
At the initial stage, the patient exhibits an increase in body temperature up to 38–39 °C. The classical clinical picture unfolds, including the following main symptoms:
- Repeated vomiting;
- Pronounced diarrhea;
- Abdominal pain;
- Tenesmus (painful false urges to defecate).
The most significant, pathognomonic sign of the infection is the change in the nature of the stool — it loses its fecal character and acquires the appearance of "rice-water stool". It is precisely these profuse fluid losses that pose the main threat to the patient's life: sharp and massive dehydration of the body.
Complications and terminal stage
If the patient does not receive timely treatment, progressive dehydration triggers a cascade of systemic disorders. First and foremost, severe disruptions occur in the cardiovascular and respiratory systems. A critical complication from the urinary system is acute renal failure.
The extreme degree of disease severity is cholera algid (from the Latin word algidus — cold). This is a terminal stage characterized by a key symptom: a catastrophic drop in body temperature to 34 °C and below. The prognosis at this stage is extremely unfavorable: without emergency intensive care, the condition inevitably results in death.
Microbiological diagnostics
Diagnostic measures are aimed at detecting the pathogen both in clinical material and in environmental objects. Stool and vomit samples are sent for analysis from the patient. Water samples, food products, hydrobionts, and swabs from various objects are investigated from the environment.
The main diagnostic method is the culture method:
- At the first stage, the material is inoculated onto an elective nutrient medium (TCBS agar is used). As an optional stage for pathogen enrichment, preliminary inoculation into alkaline peptone water followed by subculturing on TCBS agar can be used.
- Next, subculturing of colonies onto non-selective nutrient media is performed.
- At the final stage, strict identification of the isolated pure culture is carried out by studying its antigenic structure and biochemical properties.
To obtain rapid results, rapid diagnostic methods are used: the immunofluorescence assay (IFA) and polymerase chain reaction (PCR).
Principles of treatment and prevention
Comprehensive therapy of the disease is based on two key areas. First, pathogenetic treatment is used, the basis of which is rehydration — emergency replacement of massive fluid loss and essential salts. Second, etiotropic therapy is prescribed, implying the use of antibiotics to suppress the pathogen.
It should be borne in mind that post-infection immunity is characterized as weak and short-lived, so the risk of reinfection persists.
Preventive measures are divided into two groups:
- Nonspecific prevention (primary): includes strict sanitary and hygienic measures, quarantine introduction, and tight control over water supply systems.
- Specific prevention (secondary): consists of vaccination. For these purposes, killed cholera vaccine is used, as well as a complex preparation containing choleragen-toxoid and O-antigens of Ogawa and Inaba serovars.
Briefly: answers to topical questions
What biochemical tests are used for species identification of Vibrio cholerae?
To identify a pure culture of Vibrio cholerae, the assessment of biochemical properties is used. According to sources, Vibrio cholerae exhibits high enzymatic activity: it liquefies gelatin, breaks down starch and carbohydrates. On TCBS medium, characteristic yellow colonies form due to sucrose fermentation.
Which antibiotic groups are used for etiotropic therapy of cholera?
Effective antibacterial drugs are used for the etiotropic therapy of cholera. Tetracycline antibiotics and fluoroquinolones are utilized in clinical practice. Specific treatment regimens include intravenous doxycycline infusion in saline, ofloxacin, or ciprofloxacin for five days.
What degrees of dehydration are distinguished in the clinical course of cholera?
In clinical practice, when assessing the condition of a cholera patient, four degrees of dehydration are distinguished. This grading is key for determining the severity of the patient's condition, choosing the correct infusion therapy tactics, and compiling a detailed clinical diagnosis in accordance with generally accepted classifications.
Which polyionic solutions are used for intravenous rehydration in cholera?
Special saline polyionic solutions are used for intravenous rehydration in severe forms of cholera. Acesol, as well as other balanced solutions, is often used as the starting solution. This list includes such preparations as Trisol, Disol, Chlosol, Quartasol, and Lactosol.
Which serogroups and biovars of Vibrio cholerae are the causative agents of epidemic cholera?
The causative agents of epidemic cholera are bacteria of the species Vibrio cholerae belonging to the pathogenic serogroups O1 and O139. Within the O1 serogroup, two main biovars are distinguished: classical cholera vibrio (Vibrio cholerae biovar classic) and El Tor vibrio (Vibrio cholerae biovar El-Tor).
What is the antigenic structure of cholera vibrio?
The antigenic structure of cholera vibrio is represented by two main components. The first is the heat-labile flagellar H-antigen, which is common and identical across different serovars. The second is the heat-stable somatic O-antigen, according to which numerous serogroups are distinguished, including the major pathogenic serogroups O1 and O139. Within the O1 subgroup, based on the combination of antigenic fractions, the Ogawa, Inaba, and Hikojima serovars are distinguished.
To remember the inoculation algorithm: "First ALKALI gives growth (alkaline peptone water for enrichment), then TCBS selects (selective medium)."
Class and exam questions
What visual stool sign is pathognomonic for cholera?
A specific and pathognomonic sign is stool having the characteristic appearance of "rice-water stool".
What is cholera algid and why is it dangerous?
This is the extreme, terminal degree of cholera severity caused by critical dehydration. It is accompanied by a drop in body temperature below 34 °C and leads to death without intensive care.
Which nutrient medium is used as elective in diagnostics?
TCBS agar is used as an elective (selective) medium for initial specimen inoculation.
Does lasting immunity develop after recovering from cholera?
No, immunity after the disease is weak and short-lived. Therefore, cases of patient reinfection are possible in medical practice.
What else to study on this topic
- Biochemical properties of the pathogen during pure culture identification
- Features of the antigenic structure of Ogawa and Inaba serovars
- Mechanism of action of the combined vaccine (choleragen-toxoid + O-antigens)
- Operating principle of the immunofluorescence assay (IFA) in rapid infection diagnostics
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