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Volume 20, Number 8—August 2014

Letter

Babesiosis Surveillance, New Jersey, USA, 2006–2011

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Technical Appendicies

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To the Editor: Since zoonotic babesiosis was first identified in the United States in 1966 (1), its incidence and geographic range have increased (2). Previous studies have demonstrated increases in transfusion-associated cases in recent years (3). In 2011, babesiosis became nationally notifiable as its emergence and the potential for transfusion-associated cases were recognized (2,4). We assessed New Jersey, USA, surveillance data for 20062011 to characterize case information (incidence, potential transfusion associations, geographic distribution) in a state where babesiosis is endemic.

In New Jersey, babesiosis case reporting began in 1985. A retrospective study identified an upward trend during 1993–2001; eight of 21 counties reported cases (5). In 2005, the New Jersey Department of Health established the Communicable Disease Reporting Surveillance System (CDRSS) to collect detailed information for all reportable communicable diseases from clinicians, hospitals, and laboratories. Babesiosis was classified as confirmed for persons who had clinically compatible illnesses and Babesia parasites were detected by blood smear examination and as probable for persons who had clinically compatible illness, including documented anemia or thrombocytopenia, and total antibodies, shown by immunoglobulin or IgG titers of >1:256 against B. microti by indirect fluorescent test. Cases were considered possibly transfusion associated if patients had documented cellular transfusions with no (or unlikely) other risk factors (e.g., tick bites) reported in CDRSS within 6 months before illness onset. To identify possible transfusion-associated cases, we searched CDRSS text fields for “blood,” “transfusion,” and “receipt of blood donation.” We obtained supportive evidence, when available, for transfusion transmission from medical records or blood center reports. We calculated incidence rates using US Census population data for 2000 (6).

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Thumbnail of Reported confirmed and probable babesiosis cases, New Jersey, USA, 2006–2011. N = 568.

Figure. Reported confirmed and probable babesiosis cases, New Jersey, USA, 2006–2011N = 568.

During 20062011, a total of 568 babesiosis cases were reported (Figure); 521 (92%) were classified as confirmed and 47 (8%) as probable. In 2006 and 2011, 64 and 166 cases were reported, a 260% increase in reported cases; respective incidence rates were 0.76 and 1.97 cases per 100,000 population. Seven of New Jersey’s 21 counties accounted for 462 (81%) of all reported cases and for 128 (77%) of the 166 cases occurring during 2011. However, all counties reported at least 1 case within the study period, whereas only 8 counties reported cases during 1993–2001 (5) (Technical Appendix [PDF - 103 KB - 2 pages] Figure). Incidence for 20062011 ranged from 0.4 to 39.4 cases per 100,000 population; counties in southern New Jersey had the majority of cases and also reported a high incidence of Lyme disease.

Case-patients’ median age was 66 years (range 1 month–98 years). Two confirmed cases occurred in infants who were believed to have become infected by congenital transmission (7). One infant's mother was asplenic and had confirmed babesiosis. The other mother was asymptomatic and did not meet case criteria but had reported tick bites.

A total of 371 (65%) case-patients were aged >60 years of age; 395 (70%) were male. Of the 568 case patients, 401 (71%) had been hospitalized at least once. Of the 303 case-patients for whom information was available 48 (16%) were admitted to an intensive care unit. The all-cause case-fatality rate was 2% (7/357). All 7 persons who died had been hospitalized, 3 of whom had been admitted to intensive care units.

We identified 12 possible transfusion-associated cases (2 in 2006, 1 in 2007, 3 in 2009, 2 in 2010, and 4 in 2011). Two additional transfusion-associated transmissions (1 each in 2006 and 2009) were identified, but these persons were asymptomatic and not included in this study. Risk factors for possible transfusion-associated cases included surgical procedures with complications requiring transfusions. Median age and case-fatality rate were higher for patients with possible transfusion-associated babesiosis, and these patients were significantly more likely to have acquired infection outside the summer months (Technical Appendix [PDF - 103 KB - 2 pages] Table).

Our study has some limitations. Increasing awareness, electronic reporting and testing, and environmental or ecologic factors might have contributed to the upward trend and incidence fluctuations. However, neighboring jurisdictions also observed a similar geographic expansion and overall increase in incidence (8,9). Moreover, New Jersey’s Lyme disease surveillance system shows similar incidence fluctuations for Lyme disease during the study period.

Continued surveillance for detecting babesiosis and investigating possible transfusion-associated cases is needed nationwide (10). Although most cases in our study were reported during summer months, possible transfusion-associated cases were reported throughout the year, underscoring the need for constant awareness. The 2 cases of probable congenital infection highlight the need to consider Babesia infection for newborns who have compatible clinical manifestations, especially if the mother had risk factors for infection.

Prompt identification of babesiosis is essential to prevent disease transmission from infected blood donors to recipients. Although we modified New Jersey surveillance to include transfusion as a risk factor, collaboration with stakeholders (including blood centers) will further facilitate case detection and confirmation and identification of infected donors. Including babesiosis on the list of nationally notifiable diseases will improve national disease reporting and clarify the geographic distribution and incidence of tickborne and possible transfusion-associated cases. With increasing public awareness and screening, public health professionals and stakeholders might consider dedicating public health resources for babesiosis surveillance.

Andria ApostolouComments to Author , Faye Sorhage, and Christina Tan
Author affiliations: Centers for Disease Control and Prevention, Atlanta, Georgia, USA (A. Apostolou); New Jersey Department of Health, Trenton, New Jersey, USA (A. Apostolou, F. Sorhage, C. Tan)

Acknowledgment

We thank Stella Tsai for her assistance and Kris Bisgard and Barbara Herwaldt for their helpful comments.

References

  1. Scholtens RG, Braff EH, Healey GA, Gleason N. A case of babesiosis in man in the United States. Am J Trop Med Hyg. 1968;17:8103 .PubMed
  2. Centers for Disease Control and Prevention. Babesiosis surveillance—18 states, 2011. MMWR Morb Mortal Wkly Rep. 2012;61:5059 .PubMed
  3. Herwaldt BL, Linden JV, Bosserman E, Young C, Olkowska D, Wilson M. Transfusion-associated babesiosis in the United States: a description of cases. Ann Intern Med. 2011;155:50919 . DOIPubMed
  4. Centers for Disease Control and Prevention. National Notifiable Diseases Surveillance System. National notifiable infectious conditions [cited 2013 Sep 15]. http://www.cdc.gov/NNDSS/script/conditionsummary.aspx?CondID=24
  5. Herwaldt BL, McGovern PC, Gerwel MP, Easton RM, MacGregor RR. Endemic babesiosis in another eastern state, New Jersey. Emerg Infect Dis. 2003;9:1848 . DOIPubMed
  6. US Census Bureau. Census 2000 for the state of New Jersey [cited 2013 Sep 15]. http://www.census.gov/census2000/states/nj.html
  7. Sethi S, Alcid D, Kesarwala H, Tolan RW Jr. Probable congenital babesiosis in infant, New Jersey, USA. Emerg Infect Dis. 2009;15:78891 . DOIPubMed
  8. Joseph JT, Roy SS, Shams N, Visintainer P, Nadelman RB, Hosur S, Babesiosis in lower Hudson Valley, New York, USA. Emerg Infect Dis. 2011;17:8437 . DOIPubMed
  9. New York State Department of Health. Communicable disease annual reports and related information [cited 2014 Feb 15]. http://www.health.ny.gov/statistics/diseases/communicable/
  10. Centers for Disease Control and Prevention. Investigation toolkit: transfusion-transmitted infections (TTI) [cited 2013 Sep 15]. http://www.cdc.gov/bloodsafety/tools/investigation-toolkit.html

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Technical Appendix

Suggested citation for this article: Apostolou A, Sorhage F, Tan C. Babesiosis surveillance, New Jersey, USA, 2006–2011 [letter]. Emerg Infect Dis [Internet]. 2014 Aug [date cited]. http://dx.doi.org/10.3201/eid2008.131591

DOI: 10.3201/eid2008.131591

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Table of Contents – Volume 20, Number 8—August 2014

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Andria Apostolou, New Jersey Department of Health, Communicable Disease Service, 135 E State St, PO Box 369, Trenton, NJ 08625-0369, USA

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