title: Suppression of Plasmodium cynomolgi in rhesus macaques by coinfection with Babesia microti.
abstract: Both Plasmodium and Babesia species are intraerythrocytic protozoans that infect a wide range of hosts, including humans, and they elicit similar inflammatory responses and clinical manifestations that differ markedly in severity. We recently reported that a rhesus macaque that was chronically infected with Babesia microti was able to control infection with Plasmodium cynomolgi (a parasite of macaques with characteristics very similar to those of Plasmodium vivax) better than naïve monkeys. To confirm this and to investigate the underlying immunopathology, six naïve rhesus monkeys were infected with B. microti. After 24 days, four of these monkeys and four naïve rhesus monkeys were challenged with P. cynomolgi blood-stage parasites. B. microti persisted at low levels in all monkeys, and the clinical parameters were comparable to those of noninfected controls. There was a significant decrease in P. cynomolgi parasitemia in animals coinfected with B. microti compared to the parasitemia in animals infected with P. cynomolgi alone. This decrease in P. cynomolgi parasitemia correlated with increases in the levels of proinflammatory monocytes at the time of P. cynomolgi infection and with higher C-reactive protein (CRP) serum levels 1 week after malaria infection. Therefore, we conclude that ongoing infection with B. microti parasites leads to suppression of malaria infection.
authors.affiliation: Department of Parasitology, Biomedical Primate Research Centre, 2288 GJ Rijswijk, The Netherlands.
authors.forename: Leonie M
authors.initials: LM
authors.lastname: van Duivenvoorde
authors.forename: Annemarie
authors.initials: A
authors.lastname: Voorberg-van der Wel
authors.forename: Nicole M
authors.initials: NM
authors.lastname: van der Werff
authors.forename: Gerco
authors.initials: G
authors.lastname: Braskamp
authors.forename: Edmond J
authors.initials: EJ
authors.lastname: Remarque
authors.forename: Ivanela
authors.initials: I
authors.lastname: Kondova
authors.forename: Clemens H M
authors.initials: CH
authors.lastname: Kocken
authors.forename: Alan W
authors.initials: AW
authors.lastname: Thomas
mesh_terms: D000818:Animals; D041001:Babesia microti / Q000472:pathogenicity*; D001404:Babesiosis / Q000150:complications* / Q000469:parasitology / Q000473:pathology*; D001769:Blood / Q000276:immunology / Q000469:parasitology; D001774:Blood Chemical Analysis; D002097:C-Reactive Protein / Q000032:analysis; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D008253:Macaca mulatta; D008288:Malaria / Q000150:complications* / Q000469:parasitology / Q000473:pathology*; D008992:Monkey Diseases / Q000469:parasitology*; D009000:Monocytes / Q000276:immunology; D018512:Parasitemia; D016789:Plasmodium cynomolgi / Q000472:pathogenicity*
chemical_list: D002097:C-Reactive Protein