Quarantine Infections: Plague and Yellow Fever
The primary septic form of plague (pestis) proceeds fulminantly, with death occurring within 24 to 36 hours. Because of this rapid course, specific morphological changes do not have time to develop, making bacteriological diagnosis essential. In severe pulmonary or septicemic forms, organs on cross-section appear mottled, gray-red with necrosis, and the pleura exhibits fibrinous exudate. Parenchymatous organs show fatty change.
Yellow fever is a vector-borne zoonotic infection transmitted by mosquitoes. The target organs are the liver, kidneys, and blood vessels:
- Liver: Multiple parenchymal necroses lead to pronounced jaundice (staining the skin, sclera, and internal organs).
- Kidneys and heart: Icteric nephrosis, myocardial fatty degeneration.
- Hemorrhagic syndrome: Multiple hemorrhages in the stomach, intestines, and brain due to severe vasculitis.
The disease features a characteristic remission around days 4–5, after which severe cases develop cardiovascular and renal failure (up to anuria and uremic coma).
Smallpox (Variola vera)
Although officially eradicated, the cessation of mass vaccination leaves populations vulnerable. The causative agent is a large DNA poxvirus that induces specific Guarnieri bodies (cytoplasmic viral inclusions) and Paschen bodies in the epithelium.
Transmission occurs via airborne droplets or direct contact. During the incubation period (10–12 days), the patient is not contagious, and the virus undergoes minor and major viremia phases. The primary clinical sign is a skin rash evolving through distinct stages:
- Papule: Edema, swelling, and thickening of the epidermis.
- Vesicle and pustule: Ballooning and reticular degeneration (forming a multilocular blister up to 3 mm).
- Peak stage (Days 9–10): Purulent exudate in the papillary dermis with central pustular necrosis.
In extremely severe forms ("black smallpox"), massive diapedetic hemorrhages develop in the dermis. The exudate becomes hemorrhagic, and hemoglobin breakdown into iron sulfide turns the lesions black-gray. Mortality in severe forms (pustular-hemorrhagic, fulminant, confluent) reaches 100%.
Pathology of Sepsis as a Systemic Reaction
Sepsis differs fundamentally from classical infectious diseases. The primary driver of its pathogenesis is not a specific pathogen (which can be any opportunistic flora, most commonly Gram-negative), but rather an altered host reactivity (hyperergy).
Key differences of sepsis:
- No specific pathogen: Bacterial species does not alter the core clinical picture.
- No unique morphological substrate: Structural changes are stereotyped regardless of the triggering flora.
- Absence of cyclicity and immunity: The condition does not confer post-infectious protection, and tissue repair is impaired.
- Non-contagiousness: Sepsis cannot be transmitted from person to person.
- Decoupling from the primary focus: It can develop even after complete healing of the primary local infectious portal of entry.
Modern diagnosis relies on identifying SIRS criteria (Systemic Inflammatory Response Syndrome). Criteria include temperature alterations (> 38 °C or < 36 °C), tachycardia (> 90 bpm), tachypnea (> 20 breaths/min or pCO2 < 32 mmHg), and leukocyte abnormalities (> 12,000/µL, < 4,000/µL, or > 10% immature band forms). Death typically results from multiple organ dysfunction syndrome (MODS).
Autopsy Protocols for Quarantine Infections
The primary objectives for the pathologist are to prevent the spread of infection and avoid personal contamination.
Key safety requirements:
- Mandatory use of specialized biohazard containment suits (or strictly regulated multi-layered protective gear that is subsequently incinerated).
- Disconnection of autopsy room plumbing; all wastewater and fluids must be collected into sealed containers.
- Internal organs must be examined strictly in situ (within open body cavities without extraction to the table).
- Upon completion, organs and the corpse are heavily dusted with quicklime and saturated with disinfectants (e.g., lysol).
- Burial must be conducted at a depth of at least 3 meters, alternating layers of soil and quicklime. Prosectors remain quarantined until the epidemic is officially declared over.