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The Babesia observational antibody (BAOBAB) study: A cross-sectional evaluation of Babesia in two communities in Kilosa district, Tanzania.
PLoS Negl Trop Dis 2019; 13(8):e0007632PN

Abstract

BACKGROUND

Babesia, a tick-borne genus of intraerythrocytic parasites, is understudied in humans outside of established high-endemic areas. There is a paucity of data on Babesia in Africa, despite evidence that it is regionally present. A pilot study suggested that Babesia was present in a rural district of Tanzania.

METHODOLOGY/PRINCIPAL FINDINGS

A cross-sectional study was conducted July-August 2017: residents in a case hamlet that had clustering of subjects with high signal-to-cut off (S/CO) ratios for antibodies against B. microti in the pilot study, and a control hamlet that had lacked significant signal, were evaluated for B. microti. Subjects aged ≥15yrs (n = 299) underwent clinical evaluation and household inspections; 10ml whole blood was drawn for Babesia transcription mediated amplification (TMA), B. microti indirect fluorescent antibody testing (IFA) and rapid diagnostic testing (RDT) for Plasmodium spp. Subjects aged <15yrs (n = 266) underwent a RDT for Plasmodium and assessment by ELISA for B. microti antibodies. A total of 570 subjects participated (mean age 22 [<1 to 90yrs]) of whom 50.7% were female and 145 (25.5%) subjects were Plasmodium RDT positive (+). In those <15yrs, the median ELISA S/CO was 1.11 (IQR 0.80-1.48); the median S/CO in the case (n = 120) and control (n = 146) hamlets was 1.19 (IQR 0.81-1.48) and 1.06 (IQR 0.80-1.50) respectively (p = 0.4). Children ≥5yrs old were more likely to have a higher S/CO ratio than those <5yrs old (p<0.001). One hundred (38%) subjects <15yrs were Plasmodium RDT+. The median S/CO ratio (children <15yrs) did not differ by RDT status (p = 0.15). In subjects ≥15yrs, no molecular test was positive for Babesia, but four subjects (1.4%) were IFA reactive (two each at titers of 128 and 256).

CONCLUSIONS/SIGNIFICANCE

The findings offer further support for Babesia in rural Tanzania. However, low prevalence of seroreactivity questions its clinical significance.

Authors+Show Affiliations

Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America.National Institute for Medical Research, Kilosa, Tanzania.Department of Microbiology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.Dana Center for Preventive Ophthalmology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America.Dana Center for Preventive Ophthalmology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America.Dana Center for Preventive Ophthalmology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America.Dana Center for Preventive Ophthalmology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America.Kephera Diagnostics, LLC, Framingham, Massachusetts, United States of America.American Red Cross, Rockville, Maryland, United States of America.Grifols Diagnostic Solutions Inc., San Diego, California, United States of America.Grifols Diagnostic Solutions Inc., San Diego, California, United States of America.Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America.Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America.Dana Center for Preventive Ophthalmology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31412024

Citation

Bloch, Evan M., et al. "The Babesia Observational Antibody (BAOBAB) Study: a Cross-sectional Evaluation of Babesia in Two Communities in Kilosa District, Tanzania." PLoS Neglected Tropical Diseases, vol. 13, no. 8, 2019, pp. e0007632.
Bloch EM, Mrango Z, Kasubi M, et al. The Babesia observational antibody (BAOBAB) study: A cross-sectional evaluation of Babesia in two communities in Kilosa district, Tanzania. PLoS Negl Trop Dis. 2019;13(8):e0007632.
Bloch, E. M., Mrango, Z., Kasubi, M., Weaver, J., Mihailovic, A., Munoz, B., ... West, S. K. (2019). The Babesia observational antibody (BAOBAB) study: A cross-sectional evaluation of Babesia in two communities in Kilosa district, Tanzania. PLoS Neglected Tropical Diseases, 13(8), pp. e0007632. doi:10.1371/journal.pntd.0007632.
Bloch EM, et al. The Babesia Observational Antibody (BAOBAB) Study: a Cross-sectional Evaluation of Babesia in Two Communities in Kilosa District, Tanzania. PLoS Negl Trop Dis. 2019;13(8):e0007632. PubMed PMID: 31412024.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The Babesia observational antibody (BAOBAB) study: A cross-sectional evaluation of Babesia in two communities in Kilosa district, Tanzania. AU - Bloch,Evan M, AU - Mrango,Zakayo, AU - Kasubi,Mabula, AU - Weaver,Jerusha, AU - Mihailovic,Aleksandra, AU - Munoz,Beatriz, AU - Weimer,Anna, AU - Levin,Andrew, AU - Tonnetti,Laura, AU - Linnen,Jeffrey M, AU - Brès,Vanessa, AU - Norris,Douglas E, AU - Carpi,Giovanna, AU - West,Sheila K, Y1 - 2019/08/14/ PY - 2019/02/14/received PY - 2019/07/13/accepted PY - 2019/8/15/entrez PY - 2019/8/15/pubmed PY - 2019/8/15/medline SP - e0007632 EP - e0007632 JF - PLoS neglected tropical diseases JO - PLoS Negl Trop Dis VL - 13 IS - 8 N2 - BACKGROUND: Babesia, a tick-borne genus of intraerythrocytic parasites, is understudied in humans outside of established high-endemic areas. There is a paucity of data on Babesia in Africa, despite evidence that it is regionally present. A pilot study suggested that Babesia was present in a rural district of Tanzania. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional study was conducted July-August 2017: residents in a case hamlet that had clustering of subjects with high signal-to-cut off (S/CO) ratios for antibodies against B. microti in the pilot study, and a control hamlet that had lacked significant signal, were evaluated for B. microti. Subjects aged ≥15yrs (n = 299) underwent clinical evaluation and household inspections; 10ml whole blood was drawn for Babesia transcription mediated amplification (TMA), B. microti indirect fluorescent antibody testing (IFA) and rapid diagnostic testing (RDT) for Plasmodium spp. Subjects aged <15yrs (n = 266) underwent a RDT for Plasmodium and assessment by ELISA for B. microti antibodies. A total of 570 subjects participated (mean age 22 [<1 to 90yrs]) of whom 50.7% were female and 145 (25.5%) subjects were Plasmodium RDT positive (+). In those <15yrs, the median ELISA S/CO was 1.11 (IQR 0.80-1.48); the median S/CO in the case (n = 120) and control (n = 146) hamlets was 1.19 (IQR 0.81-1.48) and 1.06 (IQR 0.80-1.50) respectively (p = 0.4). Children ≥5yrs old were more likely to have a higher S/CO ratio than those <5yrs old (p<0.001). One hundred (38%) subjects <15yrs were Plasmodium RDT+. The median S/CO ratio (children <15yrs) did not differ by RDT status (p = 0.15). In subjects ≥15yrs, no molecular test was positive for Babesia, but four subjects (1.4%) were IFA reactive (two each at titers of 128 and 256). CONCLUSIONS/SIGNIFICANCE: The findings offer further support for Babesia in rural Tanzania. However, low prevalence of seroreactivity questions its clinical significance. SN - 1935-2735 UR - https://www.unboundmedicine.com/medline/citation/31412024/The_Babesia_observational_antibody_(BAOBAB)_study:_A_cross-sectional_evaluation_of_Babesia_in_two_communities_in_Kilosa_district,_Tanzania L2 - http://dx.plos.org/10.1371/journal.pntd.0007632 DB - PRIME DP - Unbound Medicine ER -