1267. Malaria in Minnesota; 1999-2009
Session: Poster Abstract Session: Travel/Tropical Medicine and Parasitology
Saturday, October 22, 2011
Room: Poster Hall B1
Background:  Malaria cases reported to the Minnesota Department of Health (MDH) increased from 5 in 1988 to 76 in 1998.  The majority occurred in travelers, but immigrants represented an increasing proportion.  The Plasmodium species was identified in 80% of cases.  Since that time, immigration from malaria-endemic regions to Minnesota (MN) has continued, and use of polymerase chain reaction (PCR) to diagnose malaria has increased.  We compare demographic and exposure patterns of malaria cases in MN from 1999-2009 to 1988-1999 and determine whether species identification has increased with PCR use.

Methods:  All cases of malaria in MN residents confirmed by microscopy reported to MDH from 1/1/99 to 12/31/09 were included.  Standard surveillance forms with demographics and clinical/exposure history reported by diagnosing providers were reviewed.

Results:  From 1999-2009, 422 cases were reported, up from 265 cases from 1988-1998.  Proportions of cases who were black or non-US born increased from 60% to 78% (p<0.0001) and 58% to 84% (p<0.0001), respectively.  Travelers represented 70% of the cases compared to 65% previously (p=0.2215).  The majority of travelers were non-US born (72%).   From 1999-2009, MN accepted 33,798 refugees from malaria-endemic regions, up 65% from 1998-1998.  Among 991 refugee screening exams, 42 cases of malaria were diagnosed.  Compared to non-immigrants, newly-immigrant cases were more likely black (p=0.0036) and previously infected (p<0.0001) but less likely to be hospitalized (p=0.0038) or experience complications from their malaria (p=0.0096).  Plasmodium species was identified in 98.2% of PCR-positive cases and 85.7% of microscopy-only cases (p<0.0001); the total proportion of cases with known species increased to 89% (p=0.0017).  

Conclusion:  More cases of malaria were reported; in both periods, numbers of cases exposed during travel exceeded cases who were new immigrants.  Among travelers, the majority of cases occurred in non-US born persons, reflecting an at-risk population of previous immigrants who visit friends and relatives in malaria-endemic areas.  Counseling and appropriate chemoprophylaxis for this group is imperative.  PCR use increases the likelihood of species identification.

Subject Category: T. Travel/tropical medicine and parasitology

Seth Sullivan, MD, MPH1, Melissa Kemperman, MPH2, David Neitzel, MS2 and Abinash Virk, MD1, (1)Infectious Disease, Mayo Clinic, Rochester, MN, (2)Minnesota Department of Health, St. Paul, MN


S. Sullivan, None

M. Kemperman, None

D. Neitzel, None

A. Virk, None

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