Quarantine infections: Plague and Yellow fever
The primary septic form of plague runs a lightning-fast course: death occurs within 1–1.5 days. Due to this speed, specific morphological changes simply do not have time to develop, so the diagnosis is made solely on bacteriological grounds. In severe forms with lung involvement (septicemia), the cut surface of the organs is mottled, gray-red, with necrosis, and fibrin is present on the pleura. Fatty degeneration is detected in parenchymatous organs.
Yellow fever is a vector-borne natural focal infection transmitted by mosquitoes. The target organs are the liver, kidneys, and blood vessels.
- Liver: multiple parenchymal necroses lead to pronounced jaundice (skin, sclerae, and organs are stained).
- Kidneys and heart: icteric nephrosis, myocardial fatty degeneration.
- Hemorrhagic syndrome: multiple hemorrhages in the stomach, intestines, and brain due to vasculitis.
The disease has a characteristic remission on days 4–5, after which, in severe cases, cardiovascular and renal failure develop (up to anuria and uremic coma).
Smallpox (Variola vera)
Although the infection has been officially eradicated, the lack of mass vaccination leaves the population unprotected. The causative agent is a large DNA virus that forms specific Guarnieri bodies (viral aggregates in the form of granules) and Paschen bodies in the epithelium.
Infection occurs via airborne or contact transmission. During the incubation period (10–12 days), the patient is not contagious; the virus goes through minor and major viremia stages. The main sign is a skin rash evolving through the following stages:
- Papule: swelling and thickening of the epidermis.
- Vesicle and pustule: ballooning and reticular degeneration (formation of a multilocular blister up to 3 mm).
- Peak stage (day 9–10): purulent exudate in the papillary layer of the dermis, necrosis in the center of the pustule.
In extremely severe cases ("black smallpox"), massive diapedetic hemorrhages develop in the dermis. The exudate in the pustules becomes hemorrhagic, and the conversion of hemoglobin into iron sulfide gives them a black-gray color. The fatality rate in severe forms (pustular-hemorrhagic, fulminant, confluent) reaches 100%.
Specifics of sepsis as a systemic reaction
Sepsis is radically different from classical infectious diseases. The main factor in its pathogenesis is not so much the pathogen (which can be any opportunistic flora, most often gram-negative), but rather altered macroorganism reactivity (hyperergy).
Fundamental differences of sepsis:
- No specific pathogen: the bacterial species does not alter the clinical presentation.
- No morphological substrate: changes are stereotyped regardless of the flora.
- Absence of cyclicity and immunity: the disease does not confer post-infection protection, and tissue repair is impaired.
- Non-contagiousness: sepsis cannot be contracted from another person.
- Association with a focus: it can develop even after complete healing of the primary local infection site.
Modern diagnostics are based on identifying SIRS (systemic inflammatory response syndrome). Its criteria include temperature changes (above 38 °C or below 36 °C), tachycardia (> 90 bpm), tachypnea (> 20/min or pCO2 < 32 mmHg), and leukocyte count abnormalities (> 12,000 or < 4,000, or > 10% band neutrophils). Death usually results from multiple organ dysfunction syndrome (MODS).
Autopsy rules in quarantine infections
The prosector's main objectives are to prevent the spread of infection and avoid self-infection.
Key requirements:
- The use of a special anti-plague suit (or a strictly regulated alternative multi-layered garment that is subsequently incinerated) is mandatory.
- If the autopsy is performed in a hospital, the dissecting room's sewage system must be shut off, and water and secretions collected in a container.
- Internal organs are examined strictly in situ (in open cavities, without removal to the table).
- Upon completion of the work, the organs and the corpse itself are generously covered with quicklime and treated with disinfectants (e.g., lysol).
- Burial is carried out to a depth of at least 3 meters with alternating layers of soil and quicklime. The prosector remains in quarantine until the epidemic is officially declared over.
Briefly: answers to topical questions
What clinical forms of plague are distinguished besides the primary septic form?
In addition to the primary septic form, the following are distinguished:
- cutaneous (skin-bubo, cellular-cutaneous);
- bubonic;
- primary pulmonary;
- secondary pulmonary;
- intestinal;
- plague meningitis;
- other forms: abortive, asymptomatic, and minor.
To remember the criteria for SIRS in sepsis, recall the "Four T's" rule: Temperature, Tachycardia, Tachypnea (or a drop in CO2), Tiny white blood cells (leukocytosis/leukopenia/shift to the left).
Class and exam questions
Due to the extremely rapid course (death in 1–1.5 days), specific morphological changes in the organs simply do not have time to form; signs of acute septicemia predominate.
During the incubation period (lasting 10–12 days), primary viral replication and two waves of viremia occur, but at this time the patient does not yet shed the virus into the environment.
What is the essence of hyperergy in sepsis?
Hyperergy means that the body mounts an unusual, excessive allergic response to the invasion of opportunistic flora, which determines the universal clinical picture regardless of the pathogen species.
How is a corpse handled after an autopsy in a quarantine infection?
The corpse and organs are covered with quicklime, poured over with a disinfectant solution (lysol), and wrapped in sheets soaked in disinfectant; they are buried in deep graves with layers of soil alternating with lime.
What else to study on this topic
- Detailed analysis of the stages of smallpox rash formation (ballooning and reticular degeneration)
- Pathogenesis of hemorrhagic syndrome in yellow fever and "black smallpox"
- Clinical and morphological forms of smallpox (varioloid, pustular, hemorrhagic)
- Pathophysiology of multiple organ dysfunction syndrome (MODS) in sepsis
- Microcirculatory disorders in systemic inflammation (sludge phenomenon, diapedetic hemorrhages)
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