APPENDIX 2

Borrelia Species Likelihood of Secondary Transmission: • Secondary transmission of relapsing fever from blood Disease Agent: exposure or blood contact with broken skin or con- • Borrelia recurrentis—Tick-borne relapsing fever junctiva, contaminated needles • B. duttoni—Louse-borne relapsing fever At-Risk Populations:

Disease Agent Characteristics: • Persons with exposure to the tick vector and people living in crowded conditions with degraded public • Not classified as either Gram-positive or Gram- health infrastructure negative, facultatively intracellular bacterium • Order: Spirochaetales; Family: Spirochaetaceae Vector and Reservoir Involved: • Size: 20-30 ¥ 0.2-0.3 mm • Nucleic acid: Approximately 1250-1570 kb of DNA • Argasid (soft) ticks: Tick-borne (endemic) relapsing fever. Rodents are the reservoir. Disease Name: • Human body louse: Louse-borne (epidemic) relaps- ing fever. No nonhuman reservoir • Relapsing fever Blood Phase: Priority Level: • Bacteria are present in high numbers in the blood • Scientific/Epidemiologic evidence regarding blood during febrile episodes and at lower levels between safety: Very low fevers. • Public perception and/or regulatory concern regard- • The duration of bacteremia is not well characterized, ing blood safety: Absent but recurrent fevers can persist for several weeks to • Public concern regarding disease agent: Very low months.

Background: Survival/Persistence in Blood Products:

• Relapsing fevers occur throughout the world, with the • No information for B. recurrentis; however, laboratory exception of a few areas in the Southwest Pacific. The studies indicate that B. burgdorferi survives in fresh distribution and occurrence of endemic tick-borne frozen plasma, RBCs, and platelets for the duration of relapsing fever (TBRF) are governed by the presence their storage period. of enzootic cycles of the transmitting tick vector. The Transmission by Blood Transfusion: distribution of epidemic louse-borne relapsing fever (LBRF) is determined by socioeconomic and ecologic • Louse- and tick-borne relapsing fevers have been factors. transmitted by laboratory exposure to clinical • TBRF samples in over 40 cases. ᭺ Caused by a number of Borrelia species through- • In the 1930s, six cases of transfusion transmission of out the world. Small outbreaks of TBRF are seen relapsing fever borreliosis (unknown types) were in the western US and spread by the bite of an reported from China, with documentation of spiro- argasid (soft) tick vector (genus Ornithodorus). chetes in blood of donors and recipients. Transmis- • LBRF sion by blood has been alleged in Africa. ᭺ Causes epidemics in crowded conditions, such as Cases/Frequency in Population: refugee camps, or times of large-scale civil dis- ruption and dislocation • Borrelia recurrentis (TBRF) is rare (Western US). ᭺ Spread by the human body louse (Pediculus • B. duttoni (LBRF) is not found in the US. humanus) Incubation Period: ᭺ Restricted mainly to the developing world and not considered a major health threat in the US, • Borrelia recurrentis (TBRF): approximately 2-18 days although imported cases do occur in travelers • B. duttoni (LBRF): 5-15 days ᭺ Infection occurs by bites or when the vector is crushed by the host. Borrelia residing in the Likelihood of Clinical Disease: hemolymph of the vector enter the host via • Appears to be significant broken skin at the bite site. Primary Disease Symptoms: Common Human Exposure Routes: • Characterized by recurring high fevers • Bite of tick or louse vector • Symptoms are absent between fevers.

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Severity of Clinical Disease: Impact on Blood Availability: • Agent-specific screening question(s): Not applicable • Can be very severe in debilitated persons • Laboratory test(s) available: Not applicable Impact on Blood Safety: Mortality: • Agent-specific screening question(s): Not applicable • Case fatality rate in untreated individuals is thought • Laboratory test(s) available: Not applicable to be between 2 and 10%. Leukoreduction Efficacy: • Fatalities may be much higher in famine victims and • Unlikely to be effective young children. Pathogen Reduction Efficacy for Plasma Derivatives:

Chronic Carriage: • Specific data indicate that the multiple steps in the fractionation process are robust and capable of inac- • No information found tivating and/or removing bacteria at concentrations that may be present in plasma. Treatment Available/Efficacious: Other Prevention Measures: • Not applicable in developed countries • Antibiotics (e.g., tetracycline, doxycycline, or • Institute de-lousing programs in refugee camps. penicillin) • In Third World or refugee environments, blood collec- • Jarisch–Herxheimer reactions are common with tion should be avoided in refugee camps, and others, treatment. where louse-borne relapsing fever has been endemic. Suggested Reading: Agent-Specific Screening Question(s): 1. Centers for Disease Control and Prevention. Tick- • No specific question is in use. borne Relapsing Fever Outbreak after a family • Not indicated because transfusion transmission is gathering—New Mexico, August 2002 Morb Mortal very infrequent, and incidence of infection in the Wkly Rep MMWR, 2003;52:809-12. population is very low. 2. Fihn S, Larson EB. Tick-borne Relapsing Fever in the • No sensitive or specific question is feasible. In Pacific Northwest: an underdiagnosed illness? West J endemic areas, a question on exposure to tick bites Med 1980;133:203-9. has been shown to be ineffective in distinguishing 3. Fritz CL, Bronson LR, Smith CR, Schriefer ME, Tucker Babesia-infected from Babesia-uninfected donors. JR, Schwan TG. Isolation and characterization of Bor- This question probably also lacks sensitivity and relia hermsii associated with two foci of Tick-Borne specificity for Borrelia species. Relapsing Fever in California. J Clin Microbiol 2004; 42:1123-8. Laboratory Test(s) Available: 4. Hira PR, Husein SF. Some transfusion induced para- sitic infections in Zambia. J Hyg Epidemiol Microbiol • No FDA-licensed blood donor screening test exists. Immunol 1979;23:436-44. • Current diagnosis reliant on microscopic and culture 5. Schwan TG, Raffel SJ, Schrumpf ME, Webster LS, methods Marques AR, Spano R, Rood M, Burns J, Hu R. Tick- borne relapsing fever and Borrelia hermsii, Los Currently Recommended Donor Deferral Period: Angeles County, California, USA. Emerging Infectious Diseases 2009;15:1026-31. • No FDA Guidance or AABB Standard exists. 6. Wang CW, Lee CU. Malaria and relapsing fever follow- • Prudent practice would be to defer donor until signs ing blood transfusion including the report of a case of and symptoms are gone and a course of treatment is congenital transmission of relapsing fever. Chin Med J completed. 1936;50:241-8.

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