Plasmodium falciparum in Asymptomatic Immigrants from Sub-Saharan Africa, Spain

To the Editor: A range of infectious diseases have been described in asymptomatic immigrants (1), which may justify the implementation of screening after obtaining consent. In particular, asymptomatic malaria caused by Plasmodium falciparum parasitemia among recently arrived immigrants may be a major public health problem outside malaria-endemic areas because these patients may be involved in autochthonous transmission cycles and may act as reservoirs capable of reintroducing malaria into areas where it had been previously eradicated. In 2010, we reviewed the medical records of 314 asymptomatic (defi ned as patients with no symptoms at the time of consultation) immigrants from sub-Saharan Africa who had settled in Spain, had not traveled to their countries of origin since arrival, and had been examined at the Tropical Medicine Unit (TMU) of the Ramon y Cajal Hospital in Madrid during the previous 5 years. Systematic screening included a blood count; serum biochemistry; basic urine analysis; serologic tests for HIV infection, hepatitis B or C infection, syphilis, and schistosomiasis (if epidemiologic risk factors were present); tuberculin skin test; analysis of fecal samples for parasites; and PCR to identify Plasmodium spp. (2). Date of arrival in Spain was obtained from the patient and corroborated by the nongovernmental organizations caring for them. PCR for Plasmodium spp. was performed for 216 patients, and 10 (4.6%) had positive test results for P. falciparum. Nine were men; median age was 27 years (interquartile range [IQR] 20–31 years). The median period from arrival in Spain to malaria diagnosis was 4.5 months (IQR 1.75– 12.5 months). Three men received a diagnosis of P. falciparum malaria >1 year after arrival. Patient 1 was a 32-year-old man from Angola who came to the TMU for screening 13 months after arriving in Spain. He was treated with a standard regimen of artesunate plus sulfadoxine/pyrimethamine; latent tuberculosis (TB) infection and schistosomiasis were also diagnosed. Patient 2 was a 17-year-old man from Senegal, seen at the TMU 14 months after arrival. Malaria treatment was not prescribed because he was lost to follow-up. He was also diagnosed with latent TB infection. Patient 3 was a 28-year-old man from Guinea who visited the TMU 28 months after arrival in Spain. He was treated with a standard regimen of atovaquone/ proguanil and also received diagnoses of tuberculosis (TB) infection, schistosomiasis, and strongyloidiasis. No statistically signifi cant association was observed between positive or negative PCR for P. falciparum and a diagnosis of …