Detection of Mansonella ozzardi among blood donors from highly endemic interior cities of Amazonas state, northern Brazil

Abstract

BACKGROUND In the Brazilian Amazon, the filarial nematode Mansonella ozzardi co‐exists with malaria parasites and thick blood smear microscopy is considered the diagnostic gold standard. Transfusion of M. ozzardi microfilariae does not establish new infections, however microfilariae can survive approximately 2 years in blood‐recipients with unknown risk of pathology. Data on transfusion‐transmitted filariasis are lacking. This study investigated M. ozzardi parasitemias in blood donors from decentralized centers of “Fundação Hematologia e Hemoterapia do Estado do Amazonas/HEMOAM,” Northern Brazil. STUDY DESIGN AND METHODS Cross‐sectional investigation employing blood smear microscopy (n = 356) and qualitative nested‐M. ozzardi‐PCR (227 out of 356) in donor candidates from 19 hemocenters in interior/rural municipalities of Amazonas state. FINDINGS: Participants were mostly young males. Positivity by microscopy was 7.9% (28 out of 356) and 23.8% by M. ozzardi‐PCR (54 out of 227). Parasitaemias were found in 16 out of 19 municipalities. In 54 M. ozzardi‐positives, 24 were ineligible; among 30 that donated, 27 were interdicted by seropositivity (22 anti‐HBc, 3 anti‐HBc + HBsAg, 1 Chagas+malaria, 1 VDRL). Seropositivty was higher in M. ozzardi‐PCR‐positives vs M. ozzardi‐PCR‐negatives (OR = 15.8, 95% CI 4.5–56.1, p < 0.0001). Three M. ozzardi contaminated blood units were transfused, but no follow‐up information on the recipients is available. MAIN CONCLUSIONS Our study provides important baseline data on M. ozzardi among blood donors from the Brazilian Amazon. Further investigations in endemic areas are necessary to clarify possible association between M. ozzardi and other infections and also to elucidate whether there is any significant clinical effect upon transfusion of contaminated blood.

Filariasis and transfusion‐associated risk: a literature review

“…In a cross‐sectional donor surveillance study of M. ozzardi in the Brazilian Amazon, 28/356 (7·9%) were smear positive and 54/227 (23·8%) were positive by a qualitative nested M. ozzardi NAT [51]. Of the 30 donations, 27 were ultimately deemed to be unusable given seroreactivity for other transfusion‐transmitted infections (TTIs) (mostly HBV, e.g.…”

“…anti‐HBc). For example, in 2019 Abrahim et al reported a 90% interdiction of M. ozzardi positive donors by the concomitant presence of other infectious markers currently used as screening tests; OR = 15·8; CI95%: 4·5–56·1, P < 0·0001] [51].…”

An Overview of the Management of Mansonellosis

“… 17 Even though it appears that contaminated blood is transfused at lower rates than what would be expected from local prevalence levels, it appears that the microfilariae from mansonellosis infections are routinely transfused through-out the developing world. 17 , 18 Although it is known that these transfusions cannot establish chronic infections, the microfilariae are known to be able to persist in the blood for over two years and could thus be contributing to transmission. 18 , 19 At present, the WHO does not provide explicit guidance on how blood stocks contaminated with microfilariae should be treated.…”

“…1,2,[14][15][16] Similarly, the chronic nature of mansonellosis infections and the disease´s broad global distribution, means the microfilariae from mansonellosis are a major contaminant of blood stocks in the developing world. 17 Even though it appears that contaminated blood is transfused at lower rates than what would be expected from local prevalence levels, it appears that the microfilariae from mansonellosis infections are routinely transfused through-out the developing world. 17,18 Although it is known that these transfusions cannot establish chronic infections, the microfilariae are known to be able to persist in the blood for over two years and could thus be contributing to transmission.…”

“…20 In a recent scoping expert panel review, it was concluded that it was unnecessary to screen for or mitigate against microfilariae contamination; however, not all experts share this view, and it appears some blood banks adopt the position that transfusion of blood contaminated in any way should be avoided. 17,[20][21][22]…”