Unresolved Splenomegaly in Recently Resettled Congolese Refugees ― Multiple States, 2015–2018

Plasmodium ovale Malaria in Travelers and Immigrants to the United States: A Case Series

Malaria in child travelers caused by Plasmodium ovale spp. is less well characterized than malaria due to other Plasmodium species. Commonly used diagnostic tests often lack adequate sensitivity to identify P. ovale spp., and a missed diagnosis may have serious consequences. We present a case series of eight children in the United States with P. ovale malaria, all of whom had traveled to or immigrated from malaria-endemic areas. Two children developed clinical malaria, including one with severe malaria; two had isolated splenomegaly; and four were asymptomatic siblings of the children with splenomegaly. Seven of the eight children had negative blood smear readings, and the diagnosis was made by polymerase chain reaction testing. Two children had concurrent P. malariae infection despite presumptive antimalarial treatment before immigration. These findings suggest a need for reconsideration of screening and diagnostic evaluation for P. ovale malaria in high-risk groups.

Clinical Sequelae Associated with Unresolved Tropical Splenomegaly in a Cohort of Recently Resettled Congolese Refugees in the United States-Multiple States, 2015-2018

Tropical splenomegaly is often associated with malaria and schistosomiasis. In 2014 and 2015, 145 Congolese refugees in western Uganda diagnosed with splenomegaly during predeparture medical examinations underwent enhanced screening for various etiologies. After anecdotal reports of unresolved splenomegaly and complications after U.S. arrival, patients were reassessed to describe long-term clinical progression after arrival in the United States. Post-arrival medical information was obtained through medical chart abstraction in collaboration with state health partners in nine participating states. We evaluated observed splenomegaly duration and associated clinical sequelae between 130 case patients from eastern Congo and 102 controls through adjusted hierarchical Poisson models, accounting for familial clustering. Of the 130 case patients, 95 (73.1%) had detectable splenomegaly after arrival. Of the 85 patients with records beyond 6 months, 45 (52.9%) had persistent splenomegaly, with a median persistence of 14.7 months (range 6.0-27.9 months). Of the 112 patients with available results, 65 (58.0%) patients had evidence of malaria infection, and the mean splenomegaly duration did not differ by Plasmodium species. Refugees with splenomegaly on arrival were 43% more likely to have anemia (adjusted relative risk [aRR]: 1.43, 95% CI: 1.04-1.97). Those with persistent splenomegaly were 60% more likely (adjusted relative risk [aRR]: 1.60, 95% CI: 1.15-2.23) to have a hematologic abnormality, particularly thrombocytopenia (aRR: 5.53, 95% CI: 1.73-17.62), and elevated alkaline phosphatase (aRR: 1.57, 95% CI: 1.03-2.40). Many patients experienced persistent splenomegaly, contradicting literature describing resolution after treatment and removal from an endemic setting. Other possible etiologies should be investigated and effective treatment, beyond treatment for malaria and schistosomiasis, explored.