An illness or post-mortem examination characterized into several distinct
clinical types, including:
Cutaneous anthrax: Usually begins as a small, painless, pruritic papule on an exposed surface, which progresses through a vesicular stage into a depressed black eschar; the eschar is often surrounded by edema or erythema and may be accompanied by lymphadenopathy. Non-specific symptoms include fever and localized edema.
Ingestion anthrax: presents as two sub-types:
Oropharyngeal: When anthrax spores germinate in the oropharynx, a mucosal lesion may be observed in the oral cavity or oropharynx. Symptoms are non-specific and include sore throat, dysphagia,swelling of the neck, fever, fatigue, shortness of breath, abdominal pain, and nausea/vomiting. Cervical lymphadenopathy, ascites, and altered mental status may be observed.
Gastrointestinal: When anthrax spores germinate in the lower gastrointestinal tract, symptoms are mainly non-specific and include abdominal pain, nausea, vomiting or diarrhea (either of which may contain blood), abdominal swelling, fever, fatigue, and headache are also common. Altered mental status and ascites may be observed.
Inhalation anthrax: Often described as a biphasic illness. Specific symptoms include pleural effusion or mediastinal widening, or hemorrhagic mediastinal lymphadenopathy. Early nonspecific symptoms of inhalation anthrax include fever and fatigue. Localized thoracic symptoms such as cough, chest pain, and shortness of breath follow, as may non-thoracic symptoms such as nausea, vomiting, abdominal pain, headache, diaphoresis, and altered mental status. Lung sounds are often abnormal.
Injection anthrax: Usually presents as a severe soft tissue infection
manifested as significant edema or bruising after an injection. No eschar is
apparent, and pain is often not described. Nonspecific symptoms such as
fever, shortness of breath, or nausea are sometimes the first indication of
illness. Occasionally patients present with meningeal or abdominal
involvement. A coagulopathy is not unusual.
Welder's anthrax:Usually presents as a pneumonia that may be accompanied by hemoptysis or pleural effusion. Unlike inhalation anthrax, mediastinal widening is not common. Non-specific symptoms include fever or chills, cough, dyspnea, and hemoptysis. Lung sounds are often abnormal.
Additional considerations:
Signs of systemic involvement from the dissemination of either the
bacteria and/or its toxins can occur with all types of anthrax and include
fever or hypothermia, tachycardia, tachypnea, hypotension, and leukocytosis.
One or more of these signs are usually present in patients with ingestion
anthrax, inhalation anthrax, and injection anthrax and may be present in up
to a third of patients with cutaneous anthrax.
Anthrax meningitis: may complicate any form of anthrax, and may also be a
primary manifestation. Primary symptoms include fever, headache (which is
often described as severe), nausea, vomiting, and fatigue. Meningeal signs
(e.g., meningismus), altered mental status, and other neurological signs such
as seizures or focal signs are usually present. Most patients with anthrax
meningitis have CSF abnormalities consistent with bacterial meningitis, and
the CSF is often described as hemorrhagic.
Clinical Criteria
Report to public health authorities any illness that meets the following criteria:
Suspicion of anthrax infection; OR
Death of an unknown cause with organ involvement consistent with anthrax;OR
In the absence of another more likely etiology, at least two of the following non-specific signs and symptoms* or at least one of the specific signs and symptoms*
Evidence of pleural effusion
Evidence of mediastinal widening or hemorrhagic mediastinal lymphadenopathy on imaging
Blood in the CSF
Painless or pruritic papular or vesicular lesion or eschar, may be surrounded by edema or erythema
Pneumonia
Laboratory Criteria
Presumptive laboratory criteria for Bacillus anthracis or Bacillus
cereus expressing anthrax toxins
Demonstration of B. anthracis antigens in tissues by immunohistochemical staining;
OR
Gram stain demonstrating Gram-positive rods, square-ended, in pairs or
short chains;
OR
Positive result on a test with established performance in a
CLIA-accredited laboratory;
Confirmatory Laboratory Evidence:
Culture and identification of B. anthracis or Bacillius spp. Expressing anthrax toxins from clinical specimens by Laboratory Response Network (LRN);
OR
Evidence of a four-fold rise in antibodies to protective antigen (PA; one of the anthrax toxins) between acute and convalescent seracollected two-four weeks apart using quantitative anti-PA IgG ELISA testing in an unvaccinated person;
OR
Evidence of a four-fold change in antibodies to protective antigen (one of the anthrax toxins) in paired convalescent sera collected two-four weeks apart using quantitative anti-PA IgG ELISA testing in an unvaccinated person;
OR
Detection of B. anthracis or anthrax toxin genes by the LRN-validated
polymerase chain reaction and/or sequencing in clinical specimens collected
from a normally sterile site (such as blood or CSF) or lesion of other
affected tissue (skin, pulmonary, reticuloendothelial, or
gastrointestinal);
OR
Detection of lethal factor (LF) in clinical serum specimens by LF mass
spectrometry.
Epidemiologic Linkage
Exposure to environment, food, animal, materials, or objects that is/are
suspected or confirmed to be contaminated with B. anthracis or anthrax toxin-producing Bacillus spp.;
OR
Exposure to the same environment, food, animal, materials, or objects as another person who has laboratory-confirmed anthrax;
Criteria to distinguish a new case of this disease or condition from
reports or notifications which should not be enumerated as a new case for
surveillance
Person not previously enumerated as a case;
OR
Person previously enumerated as a case AND newly meets confirmatory lab criteria after completing treatment for their previous infection AND had a new exposure to an anthrax-toxin producing Bacillius spp.
Case Classification
Suspect
Meets vital records criteria only.
Probable
Meets the clinical criteria AND meets presumptive laboratory evidence, OR
Meets vital records criteria AND meets presumptive laboratory evidence,OR
Meets the clinical criteria AND meets epidemiologic linkage criteria
Confirmed
Meets the clinical criteria AND meets confirmatory laboratory evidence,OR
Meets vital records criteria AND meets confirmatory laboratory evidence
For this disease/condition, Confirmed and Probable case statuses are
included in the released case count.