Tags: Bites

African Trypanosomiasis

An estimated 50 million people are at risk for acquiring African trypanosomiasis worldwide, and there are 20,000 reported new cases annually. This is likely an underestimate because reporting in endemic countries is incomplete. There are no natural life cycles of T brucei outside Africa; thus, the only cases seen outside Africa are imported.

Blastomyces Dermatitidis (Blastomycosis)

Blastomyces dermatitidis is an endemic fungus that causes acute and chronic infections in humans and other animals. It is found primarily in the south central, southeastern, and midwestern United States, especially in the states surrounding the Mississippi and Ohio Rivers. Outside the United States, cases have been reported from Canadian provinces bordering the Great Lakes, Africa, India, the Middle East, and Central and South America.

Rocky Mountain Spotted Fever (RMSF)

RMSF is caused by Rickettsia rickettsii and is an acute tick-borne illness occurring during seasonal tick activity. The disease is characterized by acute onset of fever, headache, and a rash of the extremities spreading to the trunk. A. Epidemiology.

Lyme Disease

Lyme disease is a tick-borne illness caused by the spirochete B burgdorferi. Lyme disease can be divided into early disease (stage 1, EM), disseminated infection (stage 2), and late disease (stage 3, persistent infection). The first stage involves the skin, followed by stages 2 and 3, which often affect the skin, joints, CNS, and heart.

Nocardia

Nocardia spp. are strictly aerobic, ubiquitous soil-dwelling organisms that are largely responsible for the decomposition of organic plant material. Infection usually occurs via inhalation of these organisms in airborne dust particles, leading to pulmonary disease.

Pasteurella

Pasteurella multocida has been recovered from cultures of specimens from the nasopharynx and the gastrointestinal tract of a large number of asymptomatic wild and domestic animals. The highest carriage rates occur in cats (50%-90%), dogs or swine (50%), and rats (15%). Infections are usually preceded by a cat or dog bite or scratch on an extremity.

Important Anaerobes: Clinical Syndromes

Box 1 summarizes different clinical syndromes associated with anaerobic bacteria. The sections that follow describe the various syndromes, including clinical findings. For some syndromes, specific diagnosis and treatment information is included as well.

Diphtheria

Humans are the only known natural hosts for C diphtheriae, the organism that causes diphtheria. This organism is usually spread via upper respiratory tract droplets, but it can also be spread by direct contact with skin lesions. Transmission appears to be more common when people are living indoors in crowded conditions.

Streptococcus Pyogenes

Streptococcus pyogenes is a human pathogen without an animal reservoir. Group A streptococci (GAS) cause most streptococcal disease, but other groups are important pathogens in some settings (Box 1). Group A streptococcal infections have the highest incidence in children younger than age 10. The asymptomatic prevalence is also higher (15-20%) in children, compared with that in adults (<5%).