Co-infection with Trypanosoma cruzi protects mice against early death by neurological or pulmonary disorders induced by Plasmodium berghei ANKA.
OBJECTIVE
The objective of this study was to investigate whether the infection of C57BL/6 mice by P. berghei ANKA, which causes severe malaria, was modulated by co-infection with Trypanosoma cruzi.


METHODS
Groups of C57BL/6 mice were infected either with P. berghei ANKA, T. cruzi strain G, or with both parasites. The presence of parasites was checked by microscopic examination of blood samples. Symptoms of neurological or respiratory disorders, as well as mortality, were registered. Breakdown of the blood brain barrier was determined by injecting the dye Evans blue. Histological sections of the lung were prepared and stained with hematoxilin-eosin.


RESULTS
All mice infected only with P. berghei ANKA died within 7-11 days post-infection, either with symptoms of cerebral malaria or with respiratory abnormalities. The animals co-infected with T. cruzi strain G survived longer, without any of the referred to symptoms. Protection against the early death by severe malaria was effective when mice were given T. cruzi 15 days before P. berghei inoculation. Breakdown of the blood brain barrier and extensive pulmonary oedema, caused by malaria parasites, were much less pronounced in co-infected mice. The degree of protection to severe malaria and early death, conferred by co-infection with T. cruzi, was comparable to that conferred by treatment with anti-CD8 antibodies.


CONCLUSIONS
Co-infection with T. cruzi protects C57BL/6 against the early death by malaria infection, by partially preventing either the breakdown of the blood brain, and cerebral malaria as a consequence, or the pulmonary oedema.
Egima
Claudia M
CM
Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, São Paulo, SP, Brasil. c.egima@uol.com.br <c.egima@uol.com.br>
Macedo
Silene F
SF
Sasso
Gisela Rs
GR
Covarrubias
Charles
C
Cortez
Mauro
M
Maeda
Fernando Y
FY
Costa
Fabio T
FT
Yoshida
Nobuko
N
D000818:Animals; D001812:Blood-Brain Barrier / Q000473:pathology; D008168:Lung / Q000473:pathology; D016779:Malaria, Cerebral / Q000150:complications / Q000276:immunology / Q000401:mortality / Q000469:parasitology; D051379:Mice; D008810:Mice, Inbred C57BL; D010962:Plasmodium berghei / Q000472:pathogenicity*; D011654:Pulmonary Edema / Q000150:complications* / Q000276:immunology* / Q000401:mortality / Q000469:parasitology / Q000473:pathology; D014349:Trypanosoma cruzi; D014353:Trypanosomiasis, African / Q000150:complications / Q000276:immunology / Q000401:mortality / Q000469:parasitology