Transfusion-transmitted and community-acquired babesiosis in New York, 2004 to 2015

Spatiotemporal distribution of Borrelia miyamotoi (Spirochaetales: Spirochaetaceae) and coinfection with other tick-borne pathogens in host-seeking Ixodes scapularis (Acari: Ixodidae) from New York State, USA

Blacklegged ticks (Ixodes scapularis Say, Acari: Ixodidae) were collected from 432 locations across New York State (NYS) during the summer and autumn of 2015-2020 to determine the prevalence and geographic distribution of Borrelia miyamotoi (Spirochaetales: Spirochaetaceae) and coinfections with other tick-borne pathogens. A total of 48,386 I. scapularis were individually analyzed using a multiplex real-time polymerase chain reaction assay to simultaneously detect the presence of Bo. miyamotoi, Borrelia burgdorferi (Spirochaetales: Spirochaetaceae), Anaplasma phagocytophilum (Rickettsiales: Anaplasmataceae), and Babesia microti (Piroplasmida: Babesiidae). Overall prevalence of Bo. miyamotoi in host-seeking nymphs and adults varied geographically and temporally at the regional level. The rate of polymicrobial infection in Bo. miyamotoi-infected ticks varied by developmental stage, with certain co-infections occurring more frequently than expected by chance. Entomological risk of exposure to Bo. miyamotoi-infected nymphal and adult ticks (entomological risk index [ERI]) across NYS regions in relation to human cases of Bo. miyamotoi disease identified during the study period demonstrated spatial and temporal variation. The relationship between select environmental factors and Bo. miyamotoi ERI was explored using generalized linear mixed effects models, resulting in different factors significantly impacting ERI for nymphs and adult ticks. These results can inform estimates of Bo. miyamotoi disease risk and further our understanding of Bo. miyamotoi ecological dynamics in regions where this pathogen is known to occur.

Technologies for Detection of Babesia microti: Advances and Challenges

The biology of intraerythrocytic Babesia parasites presents unique challenges for the diagnosis of human babesiosis. Antibody-based assays are highly sensitive but fail to detect early stage Babesia infections prior to seroconversion (window period) and cannot distinguish between an active infection and a previously resolved infection. On the other hand, nucleic acid-based tests (NAT) may lack the sensitivity to detect window cases when parasite burden is below detection limits and asymptomatic low-grade infections. Recent technological advances have improved the sensitivity, specificity and high throughput of NAT and the antibody-based detection of Babesia. Some of these advances include genomics approaches for the identification of novel high-copy-number targets for NAT and immunodominant antigens for superior antigen and antibody-based assays for Babesia. Future advances would also rely on next generation sequencing and CRISPR technology to improve Babesia detection. This review article will discuss the historical perspective and current status of technologies for the detection of Babesia microti, the most common Babesia species causing human babesiosis in the United States, and their implications for early diagnosis of acute babesiosis, blood safety and surveillance studies to monitor areas of expansion and emergence and spread of Babesia species and their genetic variants in the United States and globally.

Global meta-analysis on Babesia infections in human population: prevalence, distribution and species diversity

Human babesiosis is an emerging tick-borne protozoan zoonosis caused by parasites of the genus Babesia and transmitted by ixodid ticks. It was thought to be a public health problem mainly for the immunocompromised, however the increasing numbers of documented cases among immunocompetent individuals is a call for concern. In this systematic review and meta-analysis, we reported from 22 countries and 69 studies, an overall pooled estimate (PE) of 2.23% (95% CI: 1.46-3.39) for Babesia infections in humans. PEs for all sub-groups varied significantly (p < 0.05) with a continental range of 1.54% (95% CI: 0.89-2.65) in North America to 4.17% (95% CI: 2.11-8.06) in Europe. PEs for country income levels, methods of diagnosis, study period, sample sizes, Babesia species and targeted population ranged between 0.43% (95% CI: 0.41-0.44) and 7.41% (95% CI: 0.53-54.48). Babesia microti recorded the widest geographic distribution and was the predominant specie reported in North America while B. divergens was predominantly reported in Europe. Eight Babesia species; B. bigemina, B. bovis, B. crassa-like, B. divergens, B. duncani, B. microti, B. odocoilei and B. venatorum were reported in humans from different parts of the world with the highest prevalence in Europe, lower middle income countries and among individuals with history of tick bite and other tick-borne diseases. To control the increasing trend of this emerging public health threat, tick control in human settlements, the use of protective clothing by occupationally exposed people and the screening of transfusion blood in endemic countries are recommended.Abbreviations AJOL: African Journals OnLine, CI: Confidence interval, CIL: Country income level, df: Degree of freedom, HIC: Higher-income countries, HQ: High quality, I²: Inverse variance index, IFAT: Indirect fluorescent antibody test, ITBTBD: Individuals with tick-bite and tick-borne diseases, JBI: Joanna Briggs Institute, LIC: Lower-income countries, LMIC: Lower middle-income countries, MQ: Medium quality, NA: Not applicable, N/America: North America, OEI: Occupational exposed individuals, OR: Odds ratio, PE: Pooled estimates, PCR: Polymerase chain reaction, Prev: Prevalence, PRISMA: Preferred Reporting System for Systematic Reviews and Meta-Analyses, Q: Cochran's heterogeneity statistic, QA: Quality assessment, Q-p: Cochran's p-value, qPCR: Quantitative polymerase chain reaction, S/America: South America, Seq: Sequencing, UMIC: Upper middle-income countries, USA: United States of America.

Babesia blood testing: the first-year experience

BACKGROUND

Babesia is an intraerythrocytic parasite responsible for hundreds of cases of transfusion-transmitted babesiosis in the past 50 years. In May of 2020, blood testing for Babesia was implemented at the American Red Cross (ARC) for all donations in endemic areas of the northeastern and midwestern regions of the United States.

METHODS

Between May 2020 and May 2021, 1,816,669 donations from 13 states and DC were tested for Babesia by the ARC. Testing was performed in pools of 16 whole blood lysates using a licensed nucleic acid test (NAT) targeting Babesia 18S rRNA. Reactive donations were tested for B. microti antibody by immunoglobulin G immunofluorescence. Suspected cases of transfusion-transmitted babesiosis (TTB) were investigated if reported.

RESULTS

The first 13 months of Babesia screening identified 365 NAT-reactive donations. Antibodies for B. microti were detected in 79% (287) of reactive donations; negative serology samples were prevalent between May and July. Follow-up donations were collected from 142 donors, and 86% (122), collected up to 74 days after index, remained NAT reactive. Reactive donations were mainly collected in MA (77), CT (68), NY (49), NJ (47), and PA (44), but were identified in all states except Delaware. Most reactive blood donors were male (65%) aged between 40 and 80 years. Since the beginning of Babesia testing, no case of TTB was identified.

CONCLUSIONS

The absence of TTB cases since implementation of Babesia screening for blood donations collected in endemic areas suggests testing is an effective strategy to eliminate TTB.

Babesia microti: Pathogen Genomics, Genetic Variability, Immunodominant Antigens, and Pathogenesis

More than 100 Babesia spp. tick-borne parasites are known to infect mammalian and avian hosts. Babesia belong to Order Piroplasmid ranked in the Phylum Apicomplexa. Recent phylogenetic studies have revealed that of the three genera that constitute Piroplasmida, Babesia and Theileria are polyphyletic while Cytauxzoon is nested within a clade of Theileria. Several Babesia spp. and sub-types have been found to cause human disease. Babesia microti, the most common species that infects humans, is endemic in the Northeastern and upper Midwestern United States and is sporadically reported elsewhere in the world. Most infections are transmitted by Ixodid (hard-bodied) ticks, although they occasionally can be spread through blood transfusion and rarely via perinatal transmission and organ transplantation. Babesiosis most often presents as a mild to moderate disease, however infection severity ranges from asymptomatic to lethal. Diagnosis is usually confirmed by blood smear or polymerase chain reaction (PCR). Treatment consists of atovaquone and azithromycin or clindamycin and quinine and usually is effective but may be problematic in immunocompromised hosts. There is no human Babesia vaccine. B. microti genomics studies have only recently been initiated, however they already have yielded important new insights regarding the pathogen, population structure, and pathogenesis. Continued genomic research holds great promise for improving the diagnosis, management, and prevention of human babesiosis, and in particular, the identification of lineage-specific families of cell-surface proteins with potential roles in cytoadherence, immune evasion and pathogenesis.

Detection of Babesia RNA and DNA in whole blood samples from US blood donations

Background

Human babesiosis is a zoonotic infection caused by an intraerythrocytic parasite. The highest incidence of babesiosis is in the United States, although cases have been reported in other parts of the world. Due to concerns of transfusion‐transmitted babesiosis, the US Food and Drug Administration (FDA) recommended year‐round regional testing for Babesia by nucleic acid testing or use of an FDA‐approved device for pathogen reduction. A new molecular test, cobas Babesia (Roche Molecular Systems, Inc.), was evaluated for the detection of the four species that cause human disease, Babesia microti, Babesia duncani, Babesia divergens, and Babesia venatorum.

Study design and methods

Analytical performance was evaluated followed by clinical studies on whole blood samples from US blood donations collected in a special tube containing a chaotropic reagent that lyses the red cells and preserves nucleic acid. Sensitivity and specificity of the test in individual samples (individual donation testing [IDT]) and in pools of six donations were determined.

Results

Based on analytical studies, the claimed limit of detection of cobas Babesia for B. microti is 6.1 infected red blood cells (iRBC)/mL (95% confidence interval [CI]: 5.0, 7.9); B. duncani was 50.2 iRBC/mL (95% CI: 44.2, 58.8); B. divergens was 26.1 (95% CI: 22.3, 31.8); and B. venatorum was 40.0 iRBC/mL (95% CI: 34.1, 48.7). The clinical specificity for IDT was 99.999% (95% CI: 99.996, 100) and 100% (95% CI: 99.987, 100) for pools of six donations.

Conclusion

cobas Babesia enables donor screening for Babesia species with high sensitivity and specificity.

Rise in Babesiosis Cases, Pennsylvania, USA, 2005-2018

Babesiosis is an emerging infection in the state of Pennsylvania, and clinicians need to be made aware of its clinical manifestations as well as the risk factors associated with severe disease. Before 2010, our tertiary academic center in central Pennsylvania previously saw zero cases of babesiosis. We saw our first confirmed case of Babesia infection acquired in Pennsylvania in 2011; we recorded 2 confirmed cases in 2017 and 4 confirmed cases in 2018. All 4 cases from 2018 were thought to be acquired in southcentral Pennsylvania counties, whereas prior reports of cases were predominately in the southeast and northeast counties of the state.

Clofazimine, a Promising Drug for the Treatment of Babesia microti Infection in Severely Immunocompromised Hosts

BACKGROUND

Persistent and relapsing babesiosis caused by Babesia microti often occurs in immunocompromised patients, and has been associated with resistance to antimicrobial agents such as atovaquone. Given the rising incidence of babesiosis in the United States, novel drugs are urgently needed. In the current study, we tested whether clofazimine (CFZ), an antibiotic used to treat leprosy and drug-resistant tuberculosis, is effective against B. microti.

METHODS

Mice with severe combined immunodeficiency were infected with 107B. microti-infected erythrocytes. Parasites were detected by means of microscopic examination of Giemsa-stained blood smears or nested polymerase chain reaction. CFZ was administered orally.

RESULTS

Uninterrupted monotherapy with CFZ curtailed the rise of parasitemia and achieved radical cure. B. microti parasites and B. microti DNA were cleared by days 10 and 50 of therapy, respectively. A 7-day administration of CFZ delayed the rise of parasitemia by 22 days. This rise was caused by B. microti isolates that did not carry mutations in the cytochrome b gene. Accordingly, a 14-day administration of CFZ was sufficient to resolve high-grade parasitemia caused by atovaquone-resistant B. microti parasites.

CONCLUSIONS

Clofazimine is effective against B. microti infection in the immunocompromised host. Additional preclinical studies are required to identify the minimal dose and dosage of CFZ for babesiosis.

Nosocomial Infections: Do Not Forget the Parasites!

Nosocomial infections (NIs) pose an increasing threat to public health. The majority of NIs are bacterial, fungal, and viral infections; however, parasites also play a considerable role in NIs, particularly in our increasingly complex healthcare environment with a growing proportion of immunocompromised patients. Moreover, parasitic infections acquired via blood transfusion or organ transplantation are more likely to have severe or fatal disease outcomes compared with the normal route of infection. Many of these infections are preventable and most are treatable, but as the awareness for parasitic NIs is low, diagnosis and treatment are often delayed, resulting not only in higher health care costs but, importantly, also in prolonged courses of disease for the patients. For this article, we searched online databases and printed literature to give an overview of the causative agents of parasitic NIs, including the possible routes of infection and the diseases caused. Our review covers a broad spectrum of cases, ranging from widely known parasitic NIs, like blood transfusion malaria or water-borne cryptosporidiosis, to less well-known NIs, such as the transmission of Strongyloides stercoralis by solid organ transplantation or nosocomial myiasis. In addition, emerging NIs, such as babesiosis by blood transfusion or person-to-person transmitted scabies, are described.

Babesiosis Occurrence Among United States Medicare Beneficiaries, Ages 65 and Older, During 2006-2017: Overall and by State and County of Residence

Background

Human babesiosis is a mild-to-severe parasitic infection that poses health concerns especially in older and other at-risk populations. The study objective was to assess babesiosis occurrence among US Medicare beneficiaries, ages 65 and older, during 2006-2017.

Methods

Our retrospective claims-based study used Medicare databases. Babesiosis cases were identified using recorded diagnosis codes. The study estimated rates (per 100 000 beneficiary-years) overall, by year, diagnosis month, demographics, and state and county of residence.

Results

Nationwide, 19 469 beneficiaries had babesiosis recorded, at a rate of 6 per 100 000 person-years, ranging from 4 in 2006 to 9 in 2017 (P < .05). The highest babesiosis rates by state were in the following: Massachusetts (62), Rhode Island (61), Connecticut (51), New York (30), and New Jersey (19). The highest rates by county were in the following: Nantucket, Massachusetts (1089); Dukes, Massachusetts (236); Barnstable, Massachusetts (213); and Dutchess, New York (205). Increasing rates, from 2006 through 2017 (P < .05), were identified in multiple states, including states previously considered nonendemic. New Hampshire, Maine, Vermont, Pennsylvania, and Delaware saw rates increase by several times.

Conclusions

Our 12-year study shows substantially increasing babesiosis diagnosis trends, with highest rates in well established endemic states. It also suggests expansion of babesiosis infections in other states and highlights the utility of real-world evidence.

Antigen Discovery, Bioinformatics and Biological Characterization of Novel Immunodominant Babesia microti Antigens

Babesia microti is an intraerythrocytic parasite and the primary causative agent of human babesiosis. It is transmitted by Ixodes ticks, transfusion of blood and blood products, organ donation, and perinatally. Despite its global public health impact, limited progress has been made to identify and characterize immunodominant B. microti antigens for diagnostic and vaccine use. Using genome-wide immunoscreening, we identified 56 B. microti antigens, including some previously uncharacterized antigens. Thirty of the most immunodominant B. microti antigens were expressed as recombinant proteins in E. coli. Among these, the combined use of two novel antigens and one previously described antigen provided 96% sensitivity and 100% specificity in identifying B. microti antibody containing sera in an ELISA. Using extensive computational sequence and bioinformatics analyses and cellular localization studies, we have clarified the domain architectures, potential biological functions, and evolutionary relationships of the most immunodominant B. microti antigens. Notably, we found that the BMN-family antigens are not monophyletic as currently annotated, but rather can be categorized into two evolutionary unrelated groups of BMN proteins respectively defined by two structurally distinct classes of extracellular domains. Our studies have enhanced the repertoire of immunodominant B. microti antigens, and assigned potential biological function to these antigens, which can be evaluated to develop novel assays and candidate vaccines.

Transfusion transmitted babesiosis: A systematic review of reported cases

BACKGROUND

Transfusion transmitted babesiosis (TTB) has a high mortality rate but may go unrecognized, particularly in non-endemic areas. We therefore conducted a systematic review to better characterize clinical aspects of TTB.

METHODS

A literature search was conducted in PubMed and CINAHL databases, from which 25 eligible articles describing 60 TTB patients met criteria for data extraction.

RESULTS

Symptom evaluation was provided for 25 implicated donors: 18/25 (72%) were asymptomatic while 7/25 (28%) had mild flu-like symptoms but were asymptomatic at time of donation. It was common for a single donor or donation to infect multiple patients. Where reported, species included B. microti - 54/60 (90%), B. duncani - 3/60 (5%), and B. divergens-like/MO-1 - 1/60 (2%). Most TTB patients (44/60, 73%) resided in endemic states, while most TTB deaths 6/9 (67%) occurred in non-endemic states. Severity of hemolysis was proportional to degree of parasitemia. Mortality in our series was 9/60 (15%); most deaths occurred at extremes of the age spectrum: 6/9 non-survivors were aged >55 years, 2/9 were <1 year, only 1/9 was 2-54 years. Number of comorbidities was higher among non-survivors (median = 4) compared to survivors (median = 1).

CONCLUSIONS

All implicated donors (for which symptoms data were reported) resulting in TTB infections were asymptomatic at the time of donation, and it was common for a single donor or donation to infect multiple patients. Mortality of TTB appeared highest among those with more comorbidities and in non-endemic states. Heightened awareness of this diagnosis is key in its recognition.

Emerging Tick-Borne Diseases

Increases in tick-borne disease prevalence and transmission are important public health issues. Efforts to control these emerging diseases are frustrated by the struggle to control tick populations and to detect and treat infections caused by the pathogens that they transmit. This review covers tick-borne infectious diseases of nonrickettsial bacterial, parasitic, and viral origins. While tick surveillance and tracking inform our understanding of the importance of the spread and ecology of ticks and help identify areas of risk for disease transmission, the vectors are not the focus of this document. Here, we emphasize the most significant pathogens that infect humans as well as the epidemiology, clinical features, diagnosis, and treatment of diseases that they cause. Although detection via molecular or immunological methods has improved, tick-borne diseases continue to remain underdiagnosed, making the scope of the problem difficult to assess. Our current understanding of the incidence of tick-borne diseases is discussed in this review. An awareness of the diseases that can be transmitted by ticks in specific locations is key to detection and selection of appropriate treatment. As tick-transmitted pathogens are discovered and emerge in new geographic regions, our ability to detect, describe, and understand the growing public health threat must also grow to meet the challenge.

Blood Transfusion-Associated Infections in the Twenty-First Century: New Challenges

Blood transfusions are vital components of modern medical treatment to which there is no viable alternative despite efforts to create artificial blood. Each year thousands of lives are saved by blood transfusions in every country of the world. However, blood and blood products can result in significant adverse events including immunologic reactions, infections, inefficacy, and others which can sometimes result in death and severe disability. Thus, the sustainability of safe blood systems and costs are considered to be at crisis level. In industrialized countries, the risk of transfusion-transmitted infections such as HIV, syphilis, hepatitis viruses B and C are very low [generally [<1 in a million units], but in developing countries [especially in Africa] blood safety is still not assured. Compounding the problem of blood/product safety with respect to infectious agents are new emerging infectious microbes that are not being routinely tested for in blood that are donated. This chapter reviews the infectious risk of blood transfusions, types, mode and geographic variation, and the methods being used by blood services to attenuate and prevent these risks.

The Babesia observational antibody (BAOBAB) study: A cross-sectional evaluation of Babesia in two communities in Kilosa district, Tanzania

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.

Prevalence of Babesia spp. and clinical characteristics of Babesia vulpes infections in North American dogs

Background

Babesiosis is an important cause of thrombocytopenia and hemolytic anemia in dogs. Babesia vulpes, reported in European dogs and North American foxes, rarely has been reported in domestic North American dogs. Newly optimized polymerase chain reaction (PCR) primers facilitate more sensitive amplification of B. vulpes DNA.

Objectives

To determine the prevalence of Babesia sp. infections in dogs being tested for Babesia infection, and to describe co‐infections and clinicopathologic abnormalities in B. vulpes positive dogs.

Animals

Dog blood or tissue samples (n = 9367) submitted to a diagnostic laboratory between June 2015 and June 2018 were tested using an optimized Babesia PCR assay.

Methods

Comprehensive canine vector‐borne disease diagnostic testing was performed on convenience samples.

Results

Babesia sp. DNA was amplified from 269/9367 (2.9%) North American dogs. Babesia sp. infections included B. gibsoni monoinfection (157; 1.7%), B. vulpes monoinfection (19; 0.20%), and B. gibsoni and B. vulpes coinfection (29; 0.31%). Forty‐three of the 48 total B. vulpes‐infected dogs were American Pit Bull Terrier‐type breeds, of which 36 historically were involved with dog fights. Coinfections with Mycoplasma, Dirofilaria immitis, or Wolbachia and coexposures to Bartonella, Ehrlichia, and Rickettsia spp. were documented in B. vulpes‐infected dogs. Clinicopathologic data in B. vulpes‐infected dogs both with and without coinfections included anemia, thrombocytopenia, hyperglobulinemia, hypoalbuminemia, and proteinuria.

Conclusions and Clinical Importance

Babesia vulpes infection in domestic North American dogs is commonly found in conjunction with other coinfections, including B. gibsoni and hemotropic Mycoplasma. Similar to B. gibsoni, dog‐to‐dog transmission of B. vulpes may be a frequent mode of transmission.

Characteristics of transfusion-transmitted Babesia microti, American Red Cross 2010-2017

BACKGROUND

Babesia microti, a red blood cell (RBC) parasite transmitted naturally to vertebrate hosts by ixodid ticks, is endemic to the northeastern and upper midwestern United States, with the geographic range of infected ticks expanding. B. microti is a blood safety issue with >200 transfusion-transmissions reported.

METHODS

The American Red Cross's Hemovigilance program investigated hospital-reported transfusion-transmitted babesiosis (TTB) cases. Follow-up samples from involved donors were tested for B. microti antibodies and parasite DNA, the latter by real-time polymerase chain reaction (PCR). Test-positive donors were permanently deferred from future donations.

RESULTS

B. microti-positive donors were implicated in 77 of 143 suspect TTB cases investigated from 2010 through 2017. In four cases, two positive donors were identified for a total of 81 positive donors. In three cases, a RBC unit was split and components transfused multiple times to the same pediatric recipient. RBCs were the transmitting product in all cases. At follow-up, all involved donors were antibody positive; 25 donors were also PCR positive. Positive donations were collected throughout the year, peaking in the summer. Most donors (78) were resident of, or traveled to (2), an endemic state. One donor resided in a non-endemic state without relevant travel history. One fatality listed babesia as a contributing factor. No implicated donation was screened by an investigational protocol.

CONCLUSIONS

Babesiosis remains a blood safety issue. Prior to FDA-licensed screening test availability and final FDA Guidance, blood collectors in endemic states investigationally tested none, a portion, or all collections. Future expanded testing will reduce the frequency of TTB cases.

Babesiosis Surveillance - United States, 2011-2015

PROBLEM/CONDITION

Babesiosis is caused by parasites of the genus Babesia, which are transmitted in nature by the bite of an infected tick. Babesiosis can be life threatening, particularly for persons who are asplenic, immunocompromised, or elderly.

PERIOD COVERED

2011-2015.

DESCRIPTION OF SYSTEM

CDC has conducted surveillance for babesiosis in the United States since January 2011, when babesiosis became a nationally notifiable condition. Health departments in states in which babesiosis is reportable voluntarily notify CDC of cases through the National Notifiable Diseases Surveillance System (NNDSS) and submit supplemental case information by using a babesiosis-specific case report form (CRF). As of 2015, babesiosis was a reportable condition in 33 states compared with 22 states in 2011.

RESULTS

For the 2011-2015 surveillance period, CDC was notified of 7,612 cases of babesiosis (6,277 confirmed [82.5%] and 1,335 probable [17.5%]). Case counts varied from year to year (1,126 cases for 2011, 909 for 2012, 1,761 for 2013, 1,742 for 2014, and 2,074 for 2015). Cases were reported among residents of 27 states. However, 7,194 cases (94.5%) occurred among residents of seven states with well-documented foci of tickborne transmission (i.e., Connecticut, Massachusetts, Minnesota, New Jersey, New York, Rhode Island, and Wisconsin). Maine (152 cases) and New Hampshire (149 cases) were the only other states that reported >100 cases for the 5-year period, and both states also reported increasing numbers of cases over time. The median age of the 7,173 patients with available information was 63 years (range: <1-99 years; interquartile range: 51-73 years); 4,156 (57.9%) were aged ≥60 years, and 15 (<1%) were aged <1 year. The proportion of patients with symptom onset during June-August was >70% for each of the 5 surveillance years. Approximately half (3,004 of 6,404 [46.9%]) of the patients with available data were hospitalized at least overnight. Hospitalization rates ranged from 16.0% among patients aged 10-19 years (16 of 100) to 72.6% among those aged ≥80 years (552 of 760). Hospitalizations were reported significantly more often among patients who were asplenic than among patients who were not (106 of 126 [84.1%] versus 643 of 1,396 [46.1%]). Fifty-one cases of babesiosis among recipients of blood transfusions were classified by the reporting health department as transfusion associated. The median intervals from the earliest date associated with each case of babesiosis to the initial report via NNDSS and submission of supplemental CRF data to CDC were approximately 3 months and 1 year, respectively.

INTERPRETATION

For the first 5 years of babesiosis surveillance, the reported cases occurred most frequently during June-August in the Northeast and upper Midwest. Maine and New Hampshire reported increasing numbers of cases over time, which suggests that foci of transmission might be expanding. Hospitalizations were common, particularly among patients who were asplenic or elderly.

PUBLIC HEALTH ACTION

Persons who live in or travel to regions where babesiosis is endemic should avoid tick-infested areas, apply repellent to skin and clothing, conduct full-body inspections for ticks after being outdoors, and remove attached ticks with fine-tipped tweezers as soon as possible. Prevention measures are especially important for persons at risk for severe babesiosis. Increases in the number and geographic range of reported cases warrant investigation to identify contributory factors (e.g., changes in tick density or in testing or surveillance methods). Complete and timely submission of risk factor data could facilitate assessments of the geographic ranges and transmission routes of Babesia parasites. Efforts to allow for electronic submission of CRF data are under way at CDC; electronic submission is expected to improve the timeliness, uniformity, and completeness of the data.

Babesiosis in Pregnancy: An Imitator of HELLP Syndrome

HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets) is a serious pregnancy complication that can cause significant maternal and neonatal morbidity and mortality. There are several conditions that may occur in pregnancy that may imitate the laboratory findings and clinical presentation of HELLP syndrome. Babesiosis is a parasitic imitator of HELLP syndrome that can be spread by the tick, transfusions, or congenitally. Recognition and treatment of this condition is important to optimize maternal and fetal outcomes.

Research on Babesia: A bibliometric assessment of a neglected tick-borne parasite

Given the emergence and reemergence of tick-borne diseases, here we assessed the publishing patterns of research focused on Babesia. We also discuss the implications for the articles published in the last decade, and how more clinical and epidemiological information concerning Babesia is still required. The findings of this article would be useful to define research priorities about Babesia and diagnose the important of scientific production on this pathogen.

Transfusion-transmitted babesiosis: one state's experience

BACKGROUND

The risk for tickborne exposure to Babesia microti infection exists statewide in Massachusetts. Broad exposure complicates investigations of transfusion-transmitted babesiosis (TTB). We summarize 8 years of the epidemiology of TTB and highlight the role of public health in prevention and control.

STUDY DESIGN AND METHODS

Cases of babesiosis are routinely reported to the Massachusetts Department of Public Health. These are investigated to determine whether they meet the surveillance case definition and to identify whether they were potentially transfusion transmitted. Frequencies from 2009 to 2016 are described and incidence rates calculated using population denominators from the US census. Changes over time were analyzed using simple linear regression.

RESULTS

From 2009 to 2016, there were 2578 cases of babesiosis reported; of these, 45 (1.7%) were transfusion transmitted. Of the 45 cases of TTB, 15 (33%) received blood products from two or more suppliers. In 11 TTB cases, the Department of Public Health was notified first, who in turn notified the appropriate blood provider. In 2009, the crude rate of reported babesiosis was 1.2 per 100,000 population and increased significantly through 2016 to 7.8 per 100,000 population (p = 0.006). The number of blood donors reported with laboratory evidence of B. microti infection increased from 19 in 2012 to 78 in 2016; at the same time, the number of TTB cases decreased from six to three.

CONCLUSION

TTB remains a major challenge, and blood donor screening strategies are currently in the process of implementation. While population and environmental changes facilitate increases in babesiosis, donor screening has the potential to eliminate TTB.

Transfusion practices and complications in thalassemia

BACKGROUND

The severe forms of thalassemia are the most common inherited anemias managed with regular blood transfusion therapy. Transfusion policies and complications are critical to quality of life and survival, but there is a lack of standardized care.

STUDY DESIGN AND METHODS

A survey of 58 items was completed in 2016 by 11 centers in California, Washington, Oregon, Nevada, and Arizona providing long-term care for thalassemia. The questionnaire addressed demographic information, transfusion practices and complications, and educational needs.

RESULTS

The centers followed 717 patients with β-thalassemia (314, 43.8%) or α-thalassemia (394, 55%). One-third (34.7%) of patients were transfusion-dependent. Indications and goals of transfusion therapy differed between centers. Prestorage leukoreduction was universal, while routine irradiation of units was limited to one site. Red blood cell antigen phenotype was determined before the first transfusion and patients received Rh/Kell-matched units. However, more than half of the transfused patients had received blood at multiple hospitals within or outside the United States. Alloantibodies were seen in 16.9% of transfused group, but management of such patients was variable. Unusual or emerging transfusion-transmitted pathogens were not observed. Multiple educational needs were recognized, with iron overload as the biggest challenge; the approach to iron chelation varied within the group.

CONCLUSION

This study identified many patients not included in earlier surveys limited to major national centers, suggesting that the thalassemia population in the United States is vastly underestimated. Lack of evidence-based guidelines is a barrier to optimal care, which should be addressed through regional consortia of thalassemia centers.

Human Babesiosis Caused by Babesia duncani Has Widespread Distribution across Canada

Human babesiosis caused by Babesia duncani is an emerging infectious disease in Canada. This malaria-like illness is brought about by a protozoan parasite infecting red blood cells. Currently, controversy surrounds which tick species are vectors of B. duncani. Since the availability of a serological or molecular test in Canada for B. duncani has been limited, we conducted a seven-year surveillance study (2011–2017) to ascertain the occurrence and geographic distribution of B. duncani infection country-wide. Surveillance case data for human B. duncani infections were collected by contacting physicians and naturopathic physicians in the United States and Canada who specialize in tick-borne diseases. During the seven-year period, 1119 cases were identified. The presence of B. duncani infections was widespread across Canada, with the highest occurrence in the Pacific coast region. Patients with human babesiosis may be asymptomatic, but as this parasitemia progresses, symptoms range from mild to fatal. Donors of blood, plasma, living tissues, and organs may unknowingly be infected with this piroplasm and are contributing to the spread of this zoonosis. Our data show that greater awareness of human babesiosis is needed in Canada, and the imminent threat to the security of the Canadian blood supply warrants further investigation. Based on our epidemiological findings, human babesiosis should be a nationally notifiable disease in Canada. Whenever a patient has a tick bite, health practitioners must watch for B. duncani infections, and include human babesiosis in their differential diagnosis.