Parasites of the squirrel Sciurus spadiceus (Rodentia: Sciuridae) from Amazonian Brasil, with particular reference to Eimeria damnosa n. sp. (Apicompiexa: Eimeriidae).

A description is given of the mature oocysts and endogenous stages of Eimeria damnosa n. sp. from the small intestine of the red squirrel, Sciurus spadiceus, from the State of Acre, north Brazil. Ten of 12 animals examined were infected. Oocysts ovoid to ellipsoidal, occasionally cylindrical but not with parallel sides, 30.2 x 20.0 microm (18.0 x 15.0-40.2 x 30.0), shape-index (ratio length/width) 1.5 (1.3-1.8), n = 40. Oocyst wall smooth, colourless, with no micropyle, apparently of a single layer measuring approximately 1.0-1.5 microm thick. No oocyst residuum, but approximately 50 % of the oocysts with a single spherical, ovoid or dumbbell-shaped polar body. Sporocysts pear-shaped, 15.0 x 8.0 microm (11.0 x 6.0-16.0 x 8.0), shape index 1.9 (1.8-2.0), n = 33. Stieda body, if it merits this name, appears only as a slight thickening of the sporocyst wall at the more pointed extremity. Endogenous stages intracytoplasmic in the epithelial cells of the duodenum and throughout the ileum, above the host cell nucleus. Sporulation frequently completed in the lumen of the intestine, but most oocysts mature outside the host at some time within 24 hours. Massive infections may result in extensive desquamation of the gut epithelium, and sometimes in the death of the animal. In addition to this coccidian, one squirrel showed abundant trophozoites of a Giardia sp., in the ileum. The liver of two others contained developing and mature meronts, producing large numbers of slender merozoites, and other cyst-like bodies containing a small number of large zoites (sporozoites?). No parasites were detected in the blood of any of the squirrels that could be associated with this unidentified protozoan. Histological sections of the ileum of one squirrel revealed a globidium-like parasite in the lamina propria: it contained a very large number of slender, curved zoites. Three animals were with a sheathed microfilaria in the peripheral blood and liver smears. Finally, a Trypanosoma cruzi-like trypanosome was isolated from the blood of one squirrel and a T. lewisi-like trypanosome from two others.

Randomly amplified polymorphic DNA analysis of Trypanosoma rangeli and allied species from human, monkeys and other sylvatic mammals of the Brazilian Amazon disclosed a new group and a species-specific marker.

We characterized 14 trypanosome isolates from sylvatic mammals (9 from primates, 1 from sloth, 2 from anteaters and 2 from opossum) plus 2 human isolates of Brazilian Amazon. These isolates were proven to be Trypanosoma rangeli by detection of metacyclic trypomastigotes in the salivary glands of triatomines and by a specific PCR assay. Polymorphism determined by randomly amplified polymorphic DNA (RAPD) revealed that most (12) of the Brazilian T. rangeli isolates from the Amazon differed from those of other geographical regions, thus constituting a new group of T. rangeli. Four Brazilian isolates clustered together with a previously described group (A) that was described as being composed of isolates from Colombia and Venezuela. Isolates from Panama and El Salvador form another group. The isolate from Southern Brazil did not cluster to any of the above-mentioned groups. This is the first study that assesses the genetic relationship of a large number of isolates from wild mammals, especially from non-human primates. A randomly-amplified DNA fragment (Tra625) exclusive to T. rangeli was used to develop a PCR assay able to detect all T. rangeli groups.

Immunization of Saimiri sciureus monkeys with Plasmodium falciparum merozoite surface protein-3 and glutamate-rich protein suggests that protection is related to antibody levels.

The immunogenicity and protective efficacy of various antigen-adjuvant formulations derived either from the merozoite-surface protein-3 (MSP-3) or the glutamate-rich protein (GLURP) of Plasmodium falciparum were evaluated in Saimiri sciureus monkeys. These proteins were selected for immunogenicity studies based primarily on their capacity of inducing an antibody-dependent cellular inhibition effect on parasite growth. Some of the S. sciureus monkeys immunized with MSP-3(212-380)-AS02 or GLURP(27-500)-alum were able to fully or partially control parasitaemia upon an experimental P. falciparum [Falciparum Uganda Palo Alto (FUP-SP) strain] blood-stage infection, and this protection was related to the prechallenge antibody titres induced. The data are indicative that MSP-3 and GLURP can induce protective immunity against an experimental P. falciparum infection using adjuvants that are acceptable for human use and this should trigger further studies with those new antigens.

Aotus infulatus monkey is susceptible to Plasmodium falciparum infection and may constitute an alternative experimental model for malaria.

Aotus is one of the WHO-recommended primate models for studies in malaria, and several species can be infected with Plasmodium falciparum or P. vivax. Here we describe the successful infection of the species A. infulatus from eastern Amazon with blood stages of P. falciparum. Both intact and splenectomized animals were susceptible to infection; the intact ones were able to keep parasitemias at lower levels for several days, but developed complications such as severe anemia; splenectomized monkeys developed higher parasitemias but no major complications. We conclude that A. infulatus is susceptible to P. falciparum infection and may represent an alternative model for studies in malaria.

Trypanosomes of non-human primates from the National Centre of Primates, Ananindeua, State of Pará, brazil.

Trypanosome infections were sought in 46 non-human primates captured principally in Amazonian Brazil. Twenty-two (47.8%) were infected with four Trypanosoma species: T. cruzi, T. minasense, T. devei and T. rangeli. These preliminary results confirmed the high prevalence and diversity of natural infections with trypanosomes in primates from Brazilian Amazon and were the first formal record of simian infections with trypanosomes in the State of Acre. The presence of T. cruzi-like and T. rangeli-like parasites are recorded in four new hosts.

Molecular phylogeny of ateline new world monkeys (Platyrrhini, atelinae) based on gamma-globin gene sequences: evidence that brachyteles is the sister group of lagothrix.

Nucleotide sequences, each spanning approximately 7 kb of the contiguous gamma1 and gamma2 globin genomic loci, were determined for seven species representing all extant genera (Ateles, Lagothrix, Brachyteles, and Alouatta) of the New World monkey subfamily Atelinae. After aligning these seven ateline sequences with outgroup sequences from several other primate (non-ateline) genera, they were analyzed by maximum parsimony, maximum likelihood, and neighbor-joining algorithms. All three analyzes estimated the same phylogenetic relationships: [Alouatta [Ateles (Brachyteles, Lagothrix)]]. Brachyteles and Lagothrix are sister-groups supported by 100% of bootstrap replications in the parsimony analyses. Ateles joins this clade, followed by the basal genus Alouatta; these joinings were strongly supported, again with 100% bootstrap values. This cladistic pattern for the four ateline genera is congruent with that obtained in previous studies utilizing epsilon-globin, IRBP, and G6PD nuclear genomic sequences as well as mitochondrial COII sequences. Because the number of aligned nucleotide positions is much larger in the present datasetoff than in any of these other datasets, much stronger support was obtained for the cladistic classification that divides subfamily Atelinae into tribes Alouattini (Alouatta) and Atelini, while the latter divides into subtribes Atelina (Ateles) and Brachytelina (Brachyteles and Lagothrix).