Chapter 281 Babesiosis (Babesia) Peter J. Krause Babesiosis is an emerging malaria-like disease caused by intraerythrocytic protozoa that are transmitted by hard body (ixodid) ticks. The clinical manifestations of babesiosis range from subclinical illness to fulminant disease resulting in death. Etiology There are more than 90 species of Babesia that infect a wide variety of wild and domestic animals throughout the world. Only a few of these species have been reported to infect humans, including Babesia microti, Babesia divergens (and Babesia divergens–like species), Babesia duncani (previously known as WA1), Babesia venatorum (previously know as EU1), KO1, and TW1. Epidemiology Babesia are transmitted to humans from vertebrate reservoir hosts by the Ixodes ricinus family of ticks. B. microti is the most common cause of babesiosis in humans. The primary reservoir for B. microti is the white-footed mouse, Peromyscus leucopus, and the primary vector is the black legged tick, Ixodes scapularis. I. scapularis also transmits the causative agents of Lyme disease and human granulocytic anaplasmosis and may simultaneously transmit all 3 microorganisms. White-tailed deer (Odocoileus virginianus) serve as the host on which adult ticks feed most abundantly but are incompetent reservoirs. Babesiosis may be transmitted through blood transfusion, and B. microti is the most frequently reported transfusion-transmitted microbial agent in the USA. Rarely, babesiosis is acquired by transplacental transmission. Human B. microti infection is endemic in the northeastern and upper midwestern USA and in Europe. Human babesial infections caused by the cattle parasite, Babesia divergens, have been described in many countries in Europe, while B. divergens–like infections have been described in Kentucky, Missouri, and Washington. B. duncani infects humans along the Pacific coast. B. venatorum infection has been documented among people in Austria, Germany, and Italy. Human babesiosis cases also have been documented in Asia, Africa, and South America, including KO1 in Korea and TW1 in Taiwan. In certain sites and in certain years of high transmission, babesiosis constitutes a significant public health burden. Nantucket Island reported 21 such cases in 1994, which translates to 280 cases/100,000 population, placing the community burden of disease in a category with gonorrhea as “moderately common.” Comparable incidence rates have been described elsewhere on the southern New England coast. Pathogenesis The pathogenesis of human babesiosis is not well understood. Cytoadherence and lysis of infected erythrocytes and excessive production of proinflammatory cytokines such as tumor necrosis factor and interleukin-1 probably account most of the clinical manifestations and complications of the disease. The spleen has an important role in clearing parasitemia as do T and B cells, macrophages, polymorphonuclear leukocytes, cytokines, antibody, and complement. Clinical Manifestations Only gold members can continue reading. Log In or Register to continue Share this: Share on X (Opens in new window) X Share on Facebook (Opens in new window) Facebook Related Related posts: Rumination, Pica, and Elimination (Enuresis, Encopresis) Disorders Adolescent Pregnancy Neisseria gonorrhoeae (Gonococcus) Blastomycosis (Blastomyces dermatitidis) Stay updated, free articles. Join our Telegram channel Join Tags: Nelson Textbook of Pediatrics Expert Consult Jun 18, 2016 | Posted by admin in PEDIATRICS | Comments Off on Babesiosis (Babesia) Full access? Get Clinical Tree
Chapter 281 Babesiosis (Babesia) Peter J. Krause Babesiosis is an emerging malaria-like disease caused by intraerythrocytic protozoa that are transmitted by hard body (ixodid) ticks. The clinical manifestations of babesiosis range from subclinical illness to fulminant disease resulting in death. Etiology There are more than 90 species of Babesia that infect a wide variety of wild and domestic animals throughout the world. Only a few of these species have been reported to infect humans, including Babesia microti, Babesia divergens (and Babesia divergens–like species), Babesia duncani (previously known as WA1), Babesia venatorum (previously know as EU1), KO1, and TW1. Epidemiology Babesia are transmitted to humans from vertebrate reservoir hosts by the Ixodes ricinus family of ticks. B. microti is the most common cause of babesiosis in humans. The primary reservoir for B. microti is the white-footed mouse, Peromyscus leucopus, and the primary vector is the black legged tick, Ixodes scapularis. I. scapularis also transmits the causative agents of Lyme disease and human granulocytic anaplasmosis and may simultaneously transmit all 3 microorganisms. White-tailed deer (Odocoileus virginianus) serve as the host on which adult ticks feed most abundantly but are incompetent reservoirs. Babesiosis may be transmitted through blood transfusion, and B. microti is the most frequently reported transfusion-transmitted microbial agent in the USA. Rarely, babesiosis is acquired by transplacental transmission. Human B. microti infection is endemic in the northeastern and upper midwestern USA and in Europe. Human babesial infections caused by the cattle parasite, Babesia divergens, have been described in many countries in Europe, while B. divergens–like infections have been described in Kentucky, Missouri, and Washington. B. duncani infects humans along the Pacific coast. B. venatorum infection has been documented among people in Austria, Germany, and Italy. Human babesiosis cases also have been documented in Asia, Africa, and South America, including KO1 in Korea and TW1 in Taiwan. In certain sites and in certain years of high transmission, babesiosis constitutes a significant public health burden. Nantucket Island reported 21 such cases in 1994, which translates to 280 cases/100,000 population, placing the community burden of disease in a category with gonorrhea as “moderately common.” Comparable incidence rates have been described elsewhere on the southern New England coast. Pathogenesis The pathogenesis of human babesiosis is not well understood. Cytoadherence and lysis of infected erythrocytes and excessive production of proinflammatory cytokines such as tumor necrosis factor and interleukin-1 probably account most of the clinical manifestations and complications of the disease. The spleen has an important role in clearing parasitemia as do T and B cells, macrophages, polymorphonuclear leukocytes, cytokines, antibody, and complement. Clinical Manifestations Only gold members can continue reading. Log In or Register to continue Share this: Share on X (Opens in new window) X Share on Facebook (Opens in new window) Facebook Related Related posts: Rumination, Pica, and Elimination (Enuresis, Encopresis) Disorders Adolescent Pregnancy Neisseria gonorrhoeae (Gonococcus) Blastomycosis (Blastomyces dermatitidis) Stay updated, free articles. Join our Telegram channel Join Tags: Nelson Textbook of Pediatrics Expert Consult Jun 18, 2016 | Posted by admin in PEDIATRICS | Comments Off on Babesiosis (Babesia) Full access? Get Clinical Tree
