Vesicular stomatitis Vesicular stomatitis virus Horses, cattle, swine Direct contact Americas
Babesiosis Babesia Cattle, wild and Tick bite (I. scapularis), Worldwide domestic rodents blood transfusion
Leishmaniasis, Leishmania Domestic and wild dogs Sandfly bite Tropics mucocutaneous and cutaneous
Leishmaniasis, visceral Leishmania donovani Domestic and wild dogs Sandfly bite Tropics complex
Malaria Plasmodium Humans Mosquito bite (Anopheles) Usually imported to the United States, Southern California
Toxoplasmosis Toxoplasma gondii Cats, livestock, pigs Ingestion of oocysts in Worldwide fecally contaminated material or ingestion of tissue cysts in undercooked meat
Adapted from Christenson JC: Epidemiology of infectious diseases. In Jenson HB, Baltimore RS, editors: Pediatric Infectious Diseases: Principles and Practice, ed 2,
Philadelphia, 2002, Saunders, pp 18−20.
*Many helminths are also zoonotic (see Tables 123-4 and 123-5).
late neurologic disease (other than facial nerve or other cranial nerve palsy) are treated with intravenous or intramuscular ceftriaxone or intravenous penicillin G for 14 to 28 days. Arthritis is treated with doxycycline (for children >9 years of age) or amoxicillin for 28 days. If there is recurrence, treatment should be with a repeated oral regimen or with the regimen for late neurologic disease.
Carditis, especially conduction disturbances, and arthritis are the major complications of Lyme disease. Even untreated, most cases eventually resolve without sequelae.
Lyme disease is readily treatable and curable. The long-term prognosis is excellent for early and late disease. Early treatment may prevent progression to carditis and meningitis. Recurrences of arthritis are rare after recommended treatment.
A community-based study of children with Lyme disease found no evidence of impairment 4 to 11 years later.
Measures to minimize exposure to tick-borne diseases are the most reasonable means of preventing Lyme disease. Postexposure prophylaxis is not routinely recommended because the overall risk of acquiring Lyme disease after a tick bite is only 1% to 2% even in endemic areas, and treatment of the infection, if it develops, is highly effective. Nymphal stage ticks must feed for 36 to 48 hours, and adult ticks must feed for 48 to 72 hours before the risk of transmission of B. burgdorferi from infected ticks becomes substantial. In hyperendemic regions, prophylaxis of adults with doxycycline, 200 mg as a single dose, within 72 hours of a nymphal tick bite is effective in preventing Lyme disease.
The cause of Rocky Mountain spotted fever is R. rickettsii, gram-negative coccobacillary organisms that resemble bacteria but have incomplete cell walls and require an intracellular site for replication. The organism invades and proliferates within the endothelial cells of blood vessels, causing vasculitis and resulting in increased vascular permeability, edema, and, eventually, decreased vascular volume, altered tissue perfusion, and widespread organ failure. Many tick species are capable of transmitting R. rickettsii. The principal ticks are the American dog tick (Dermacentor variabilis) in the eastern United States and Canada, the wood tick (Dermacentor andersoni) in the western United States and Canada, the brown dog tick (Rhipicephalus sanguineus) in Mexico, and Amblyomma cajennense in Central and South America.