Capnocytophaga Information for Healthcare Professionals

Signs and Symptoms of Capnocytophaga Infection

Signs and symptoms of Capnocytophaga infection can vary widely from skin to invasive infections. Symptom onset begins 3 to 5 days after an animal bite, but can range from 1 to 14 days. Symptoms can progress rapidly from mild, localized infection to systemic infection, including sepsis, organ failure, meningitis, and disseminated intravascular coagulation (DIC).

images of health care workers

Who Is at Risk?

People at greater risk of disease include individuals with:

  • Splenectomies
  • History of excessive alcohol use
  • Cancer
  • Chronic lung disease

These groups comprise 60% of Capnocytophaga infections.

Asplenic patients have a 30 to 60 times greater risk of death from Capnocytophaga infections; these patients can advance to organ failure and death within 24 to 72 hours of onset.

Severely immunocompromised patients are more likely to be infected with the endogenous human Capnocytophaga species, while patients who have liver disease or are asplenic have a greater association with zoonotic transmission.

Treatment of Capnocytophaga infection

Capnocytophaga is typically sensitive to routinely used antibiotics. Healthcare providers can determine the most appropriate course of treatment based on patient’s history and clinical presentation.


Morbidity can be high, and can include sepsis, myocardial infarction, renal failure, and amputation because of disseminated intravascular coagulation (DIC).

Even with treatment, mortality can be as high as 30% and death can occur in as little as 24 hours, many times due to complications from shock, DIC, and organ failure.

Surveillance, Incidence, and Trends

Capnocytophaga infections are not nationally notifiable, and thus there is no national estimate of incidence. Cases are rarely reported in the literature.

Laboratory Identification of Capnocytophaga

Capnocytophaga species are fastidious, slow-growing, Gram-negative bacteria. Blood samples are usually used for culture identification. Identification can be difficult; in a study of California specimen submissions to the state Public Health laboratory, only approximately one third of Capnocytophaga isolates were correctly identified by submitting laboratories.

Capnocytophaga species are fastidious, slow-growing, Gram-negative bacteria.

Automated blood culture systems may not identify Capnocytophaga spp. growth because of its slow-growing nature. Some species are very similar, and biochemical analysis may not sufficiently differentiate at the species level.

Other methods of identification include PCR, 16S rRNA gene amplification, and Matrix Assisted Laser Desorption/Ionization Time of Flight (MALDI TOF) mass spectrometry. CDC’s Special Bacteriology Reference Laboratory or your state health department laboratory can conduct these tests.

MicrobeNet, a CDC virtual reference laboratory, can also help with identification of rare pathogens such as Capnocytophaga. Request access to MicrobeNet.

To submit a sample to CDC for Capnocytophaga spp. identification, see laboratory submission information.

All submissions to CDC must come from within the United States and must be approved by your state health department.