title: Species-specific escape of Plasmodium sporozoites from oocysts of avian, rodent, and human malarial parasites.
abstract: BACKGROUND
  Malaria is transmitted when an infected mosquito delivers Plasmodium sporozoites into a vertebrate host. There are many species of Plasmodium and, in general, the infection is host-specific. For example, Plasmodium gallinaceum is an avian parasite, while Plasmodium berghei infects mice. These two parasites have been extensively used as experimental models of malaria transmission. Plasmodium falciparum and Plasmodium vivax are the most important agents of human malaria, a life-threatening disease of global importance. To complete their life cycle, Plasmodium parasites must traverse the mosquito midgut and form an oocyst that will divide continuously. Mature oocysts release thousands of sporozoites into the mosquito haemolymph that must reach the salivary gland to infect a new vertebrate host. The current understanding of the biology of oocyst formation and sporozoite release is mostly based on experimental infections with P. berghei, and the conclusions are generalized to other Plasmodium species that infect humans without further morphological analyses.
  
  
  RESULTS
  Here, it is described the microanatomy of sporozoite escape from oocysts of four Plasmodium species: the two laboratory models, P. gallinaceum and P. berghei, and the two main species that cause malaria in humans, P. vivax and P. falciparum. It was found that sporozoites have species-specific mechanisms of escape from the oocyst. The two model species of Plasmodium had a common mechanism, in which the oocyst wall breaks down before sporozoites emerge. In contrast, P. vivax and P. falciparum sporozoites show a dynamic escape mechanism from the oocyst via polarized propulsion.
  
  
  CONCLUSIONS
  This study demonstrated that Plasmodium species do not share a common mechanism of sporozoite escape, as previously thought, but show complex and species-specific mechanisms. In addition, the knowledge of this phenomenon in human Plasmodium can facilitate transmission-blocking studies and not those ones only based on the murine and avian models.
authors.affiliation: Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brazil.
authors.forename: Alessandra S
authors.initials: AS
authors.lastname: Orfano
authors.affiliation: Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brazil.
authors.forename: Rafael
authors.initials: R
authors.lastname: Nacif-Pimenta
authors.affiliation: Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brazil.|Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM, Brazil.
authors.forename: Ana P M
authors.initials: AP
authors.lastname: Duarte
authors.affiliation: Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brazil.
authors.forename: Luis M
authors.initials: LM
authors.lastname: Villegas
authors.affiliation: Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brazil.
authors.forename: Nilton B
authors.initials: NB
authors.lastname: Rodrigues
authors.affiliation: Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brazil.
authors.forename: Luciana C
authors.initials: LC
authors.lastname: Pinto
authors.affiliation: Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM, Brazil.
authors.forename: Keillen M M
authors.initials: KM
authors.lastname: Campos
authors.affiliation: Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM, Brazil.
authors.forename: Yudi T
authors.initials: YT
authors.lastname: Pinilla
authors.affiliation: Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brazil.|Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM, Brazil.
authors.forename: Bárbara
authors.initials: B
authors.lastname: Chaves
authors.affiliation: Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM, Brazil.
authors.forename: Maria G V
authors.initials: MG
authors.lastname: Barbosa Guerra
authors.affiliation: Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM, Brazil.
authors.forename: Wuelton M
authors.initials: WM
authors.lastname: Monteiro
authors.affiliation: Department of Entomology, Iowa State University, Ames, IA, USA.|Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Smith
authors.affiliation: Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, MD, USA.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Molina-Cruz
authors.affiliation: Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM, Brazil.|Instituto Leônidas e Maria Deane-Fiocruz, Manaus, AM, Brazil.
authors.forename: Marcus V G
authors.initials: MV
authors.lastname: Lacerda
authors.affiliation: Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brazil.
authors.forename: Nágila F C
authors.initials: NF
authors.lastname: Secundino
authors.affiliation: Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Jacobs-Lorena
authors.affiliation: Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, MD, USA.
authors.forename: Carolina
authors.initials: C
authors.lastname: Barillas-Mury
authors.affiliation: Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brazil. pimenta@cpqrr.fiocruz.br.|Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM, Brazil. pimenta@cpqrr.fiocruz.br.
authors.forename: Paulo F P
authors.initials: PF
authors.lastname: Pimenta
mesh_terms: D000818:Animals; D001717:Birds; D005260:Female; D006801:Humans; D008018:Life Cycle Stages; D051379:Mice; D008855:Microscopy, Electron, Scanning; D033661:Oocysts / Q000469:parasitology* / Q000648:ultrastructure*; D010961:Plasmodium / Q000502:physiology* / Q000648:ultrastructure*; D034101:Sporozoites / Q000502:physiology* / Q000648:ultrastructure*
keywords: Avian; Human; Mosquito vector; Murine; Oocyst; Plasmodium; Sporozoite escape