Infection of Peruvian Aotus nancymai monkeys with different strains of Plasmodium falciparum, P. vivax, and P. malariae

Aotus nancymai (karyotype I) monkeys from Peru were studied for their susceptibility to infection with Plasmodium falciparum, P. vivax, and P. malariae. Three strains of P. falciparum (Santa Lucia from El Salvador, Indochina I/CDC from Thailand, and Uganda Palo Alto) were inoculated into 38 monkeys. The results indicated that this species of Aotus monkey is highly susceptible to infection. The Uganda Palo Alto and the Santa Lucia strain parasites appear to be the most useful for immunologic and chemotherapeutic studies. Five strains of P. vivax (Chesson, ONG, Vietnam Palo Alto, Salvador I, and Honduran I/CDC) were inoculated into 28 monkeys. The Vietnam Palo Alto strain produced the highest level parasitemias ranging from 23,800 to 157,000/mm3. Mosquito infections were obtained with the ONG, Chesson, and Salvador I strains. Two out of 6 attempts to transmit P. vivax via sporozoite inoculation to splenectomized monkeys were successful with prepatent periods of 39 and 57 days. Five monkeys were infected with the Uganda I/CDC strain of P. malariae. Maximum parasitemias ranged from 10 to 5,390/mm3.

Transmission of the OS strain of Plasmodium inui to Saimiri sciureus boliviensis and Aotus azarae boliviensis monkeys by Anopheles dirus mosquitoes

Eight Saimiri and 7 Aotus monkeys were exposed to infection with the OS strain of Plasmodium inui via the bites of from 2 to 7 Anopheles dirus mosquitoes. All Saimiri monkeys developed high-level infections of from 152,000 to 500,000/mm3 after prepatent periods of from 14 to 17 days. Only 1 Aotus monkey developed a patent infection after a period of 28 days. Feeding on these animals failed to result in infection of An. dirus mosquitoes.

Acute Chagas' disease in non-human primates. 1. Chronology of clinical events, clinical chemistry, ECG, radiology, parasitemia, and immunological parameters in the Cebus apella monkey

Forty Cebus apella monkeys free from Chagas' disease were subcutaneously infected with 3 x 10(5) trypomastigotes of the Ypsilon strain of T. cruzi and followed-up for 6 months. Seventeen monkeys were controls. Body weight, temperature, direct parasitemia (DP), IgM and IgG were determined weekly. Hematology was performed weekly up to day 40 p.i. and monthly thereafter. Clinical chemistry was performed every two weeks up to day 33 p.i. and monthly thereafter. ECG was performed weekly up to day 47 p.i. and at 2,3, and 6 months p.i. Chest X-ray was done at 45 days, 4 and 6 months p.i. Xenodiagnosis was only performed after two negative DP. All infected monkeys developed fever, beginning 6.0 +/- 0.6 day p.i. and lasting 21.9 +/- 6.7 days, and lost 14% of their body weight the first month, 11% the third month and 7% the 6th month. DP was already detected 4.4 +/- 0.29 days after infection and it was detectable in all monkeys up to 96.0 +/- 6.9 days p.i. Cyclical peaks of parasitemia were observed throughout the study. IgM and IgG titers which permitted a diagnosis of T. cruzi infection occurred at 33.0 +/- 2.9 days p.i., respectively. Fifty-seven percent of infected monkeys presented ECG alterations one week after inoculation reaching a maximum of 86% at the third week. A normocytic, normochromic anemia was observed in all monkeys being significantly (p less than 0.02) more severe in the infected animals. No effects of T. cruzi on the clinical chemistry were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term protection of squirrel monkeys (Saimiri sciureus) against Plasmodium falciparum challenge inoculations after various time intervals

When used as an experimental host for Plasmodium falciparum, the squirrel monkey Saimiri sciureus, intact or splenectomized, develops a significant, long-lasting, protective immunity against the blood stages of this parasite. In the present study, this length of protection after a single initial infection was determined by test infections carried out at varying intervals of time in 26 splenectomized animals. An initial period of about 7 months was observed, which was characterized by a marked resistance to trial reinfestations by a homologous as well as a heterologous strain. A second period was observed during which the primates became sensitive to the parasite in varying degrees. These observations single out the squirrel monkey in comparison with other experimental hosts tested under similar conditions and underline the value of research on antimalarial vaccinations, because when confronted with parasite antigens, the organism can produce the immunological response necessary to control a test infection.

Characterization by anti-Ig monoclonal antibodies of protective and non-protective antibodies against asexual forms of Plasmodium falciparum in the Saimiri monkey

Four monoclonal antibodies (mAb) which recognize distinct epitopes on Saimiri immunoglobulins were successfully used to characterize the protective and non-protective antibodies developed by this experimental host in response to infection by the human malaria parasite Plasmodium falciparum. Two of these mAb, 3F11/G10 and 3E4/H8, were IgG-specific and directed against conformationally conserved epitopes on the intact molecule. mAb 3A2/G6 and 4G3/B5 were specific for epitopes on two distinct L chain types of all Ig. Radioimmunoassay and immunoblots indicated that L-chains defined by 3A2/G6 were present in IgG molecules of type 3F11/G10, while L chains defined by 4G3/B5 were associated with IgG of type 3E4/H8. The use of these four mAb as immunoadsorbents allowed the purification of two IgG and two Ig populations. When assayed in vivo by passive transfer experiments in recipient monkeys previously infected by P. falciparum, protection could be associated with the IgG or Ig populations of type 3F11/G10-3A2/G6. In contrast, recipient animals which received the IgG type 3E4/H8 or Ig type 4G3/B5 presented rapidly evolving parasitemia similar to that in animals which received non-immune IgG or protective immune sera depleted of the above Ig or IgG fractions. The identification of protective and non-protective Ig populations will help in the evaluation of vaccine candidates against P. falciparum.

Chesson strain Plasmodium vivax in Saimiri sciureus boliviensis monkeys

Nine Saimiri sciureus boliviensis monkeys were inoculated with sporozoites of Plasmodium vivax (Chesson strain) dissected from Anopheles stephensi mosquitoes infected by feeding on blood from infected chimpanzees. The animals were splenectomized 7 days after inoculation. Seven animals developed infections with prepatent periods ranging from 12 to 43 days (mean of 19.6 days). Parasitemias were low during the first 50 days. Maximum parasitemias in 5 animals in which the strain adapted ranged from 10,000 to 46,800 per mm3. Anopheles freeborni mosquitoes were infected by feeding on 4 of the monkeys.

Adaptation of the Panama II strain of Plasmodium falciparum to Panamanian owl monkeys

The Panama II strain of Plasmodium falciparum, acquired at the second passage level in splenectomized Colombian owl monkeys, was adapted to owl monkeys of Panamanian origin. Patent infections were induced in 22 of 27 unaltered and 20 of 21 splenectomized recipients during 19 serial passages. The infections were significantly more virulent in splenectomized than normal Panamanian owl monkeys, however recrudescences in seven normal monkeys achieved peak parasitemias 48 times greater than in the primary attack. These results describe the first reproducible infections of indigenous falciparum malaria in Panamanian owl monkeys.

Pathologic changes associated with fatal Plasmodium falciparum infection in the Bolivian squirrel monkey (Saimiri sciureus boliviensis)

Fatal cases of experimental Plasmodium falciparum (Indochina I) in Bolivian squirrel monkeys (Saimiri sciureus boliviensis) were examined by histologic and ultrastructural methods. Gross lesions were characterized by hepatosplenomegaly and interstitial pulmonary changes. Histologically, there was marked diffuse reticuloendothelial hyperplasia, pulmonary alveolar septal thickening, mesangioproliferative glomerulonephropathy, sequestration of parasitized erythrocytes in deep vascular beds, degenerative parenchymal changes in the liver and myocardium, and in one case retinal and cerebral hemorrhage. These data indicate that the Bolivian squirrel monkey is a good model for studying pathologic changes associated with human falciparum malaria.

Infection of Aotus vociferans (karyotype V) monkeys with different strains of Plasmodium vivax

Twenty splenectomized Aotus vociferans (karyotype V) monkeys were infected with strains of Plasmodium vivax from New Guinea, North Korea, Indonesia, El Salvador, and Honduras. Peak parasite densities ranged from 4,840 to 75,500 per mm3. Gametocytes infective to different species of mosquitoes were produced with all strains of P. vivax studied. Two transmissions of the Chesson strain of P. vivax were made by the intravenous inoculation of dissected sporozoites from An. dirus mosquitoes. Prepatent periods were 16 days.

In vitro and in vivo adaptation of the Geneve/SGE-1 strain of Plasmodium falciparum to growth in a squirrel monkey (Saimiri sciureus) model

Human erythrocytic culture-adapted parasites of the Geneve/SGE-1 strain of Plasmodium falciparum were successfully adapted to grow in an in vitro culture system containing squirrel monkey erythrocytes and serum. These monkey culture-adapted organisms were then used to produce a patent infection in a splenectomized squirrel monkey. Fresh infected blood from this animal was introduced into another splenectomized monkey and was subsequently serially passed through seven intact squirrel monkeys. High level parasitemias (greater than 10%) were obtained in the animals from the last two passes following inoculation of moderate numbers of parasites. It is anticipated that this squirrel monkey-adapted Geneve/SGE-1 strain of P. falciparum will continue to produce high level parasitemias in intact Bolivian Saimiri, and consequently will be suitable for challenge of these monkeys.

[A 5th filaria of the genus Dipetalonema, parasite of South American monkeys]

Description of D. freitasi n. sp., a parasite of Cebus capucinus: this species, close to D. caudispina, is distinguished by the slightly more complex structure of the vagina and right spicule, the lack of area rugosa on the tail and by the shorter microfilaria. Additional morphological data on the male of D. robini Petit et al., 1985 are given. A comparative table of 4 principal evolutive characters of the genus Dipetalonema (vagina, left and right spicules, epithelio-muscular body wall) is given. D. caudispina and D. freitasi n. sp. represent a small primitive group opposed to the more evolved one made up of D. robini, D. gracile and D. graciliformis.

Experimental visceral leishmaniasis in the owl monkey

Visceral leishmaniasis developed in eight owl monkeys (Aotus trivirgatus) after intravenous inoculation with a Khartoum strain (WR378) of Leishmania donovani. Six monkeys died within 93 days, and two monkeys recovered from the disease. Clinically, signs were weight loss, anemia, and hepatosplenomegaly. Hematologic findings included anemia, granulocytopenia, thrombocytopenia, and lymphocytosis. Analysis of serum or plasma revealed hyperbilirubinemia, azotemia, hyperglobulinemia, hypoalbuminemia, and altered hemostasis. All monkeys developed positive antibody titers to promastigotes of L. donovani and had increases in immunoglobulins M and subsequently G. Liver, spleen, bone marrow, and lymph nodes were the principal organs containing numerous parasitized macrophages. The owl monkey was highly susceptible to L. donovani infection and should be a useful animal model for the study of visceral leishmaniasis.

Tritrichomonas mobilensis n. sp. (Zoomastigophorea: Trichomonadida) from the Bolivian squirrel monkey Saimiri boliviensis boliviensis

A trichomonad flagellate, Tritrichomonas mobilensis n. sp., is described from the large intestine of the squirrel monkey, Saimiri boliviensis boliviensis. The organism has a lanceolate body 7-10.5 micrometers in length; a well developed undulating membrane; a stout, tubular axostyle with periaxostylar rings that terminate in a cone-shaped segment projecting from the posterior end of the cell; and a moderately wide costa. The anterior flagella are about as long as the body, and the recurrent flagellum is of the acroneme type. All its characteristics suggest that the new species belongs in the Tritrichomonas augusta type of the subfamily Tritrichomonadinae.

Adaptation of the Indochina I/CDC strain of Plasmodium falciparum to the squirrel monkey (Saimiri sciureus)

The Indochina I/CDC strain of Plasmodium falciparum was linearly passaged in squirrel monkeys (Saimiri sciureus) of 3 phenotypes. Splenectomized monkeys of Guyanan and Peruvian type developed high density parasitemias, but considerably lower than the mean peak parasitemia (greater than 10(6)/mm3) in Bolivian phenotype squirrel monkeys. Spleen-intact Bolivian and Peruvian squirrel monkeys all developed potentially lethal infections after linear passage of parasites from Saimiri and Aotus. For the evaluation of induced immunity to P. falciparum, the Indochina I/CDC strain in Saimiri will be a valuable model system.

Trypanosoma cruzi and Trypanosoma rangeli in Saimiri sciureus from Bolivia and Saguinus mistax from Brazil

Examination of blood films for trypanosomes in primates housed at the Tulane University Delta Regional Primate Research Center showed that 47% (32/68) of the Bolivian Saimiri sciureus and 51% (68/135) of Brazilian Saguinus mistax harbored one or more types: Trypanosoma (Schizotrypanum) cruzi in 6% to 7% and Trypanosoma (Herpetosoma) spp. or Trypanosoma (Megatrypanum) spp. in 39% and 45%, respectively. Trypanosomes were isolated from a sample of the infected monkeys and morphobiological studies were carried out. Both T. cruzi and Trypanosoma rangeli were demonstrated. The transmission of T. rangeli by Rhodnius prolixus, Rhodnius neglectus, and Triatoma infestans was assessed: only R. prolixus transmitted the infection by bite. T. rangeli has not been found previously in Bolivia, nor has any trypanosome been reported previously in Saguinus mistax.

Studies on a newly isolated strain of Plasmodium brasilianum in Aotus and Saimiri monkeys and different anophelines

A strain of Plasmodium brasilianum was isolated from an Aotus vociferans monkey from Peru. The parasite readily infected Aotus monkeys from Bolivia and Columbia and Saimiri sciureus monkeys from Peru and Bolivia. Highest level mosquito infections were obtained by feeding on the Saimiri monkeys. The most susceptible mosquito was Anopheles freeborni, followed by Anopheles dirus, Anopheles stephensi, Anopheles gambiae, Anopheles culicifacies, Anopheles maculatus and Anopheles albimanus. Anopheles quadrimaculatus were also susceptible to infection. Degenerating oocysts were observed in An. dirus mosquitoes infected with this parasite. Transmission via the bites of infected An. maculatus mosquitoes was obtained to 3 Bolivian Saimiri monkeys; prepatent periods were 27, 27, and 29 days.

Comparison of Plasmodium falciparum infections in Panamanian and Colombian owl monkeys

Parameters of blood-induced infections of the Vietnam Oak Knoll, Vietnam Smith, and Uganda Palo Alto strains of Plasmodium falciparum studied in 395 Panamanian owl monkeys in this laboratory between 1976-1984 were compared with those reported from another laboratory for 665 Colombian owl monkeys, studied between 1968-1975, and, at the time, designated Aotus trivirgatus griseimembra. The virulence of these strains was less in Panamanian than in Colombian owl monkeys, as indicated by lower mortality rates of the Panamanian monkeys during the first 30 days of patency. Maximum parasitemias of the Vietnam Smith and Uganda Palo Alto strain, in Panamanian owl monkeys dying during the first 15 days of patent infection, were significantly higher than in Colombian owl monkeys. Panamanian owl monkeys that survived the primary attack had significantly higher maximum parasitemias than the surviving Colombian owl monkeys. Peak parasitemias were attained significantly earlier after patency in Panamanian than in Colombian owl monkeys, irrespective of the strain of P. falciparum. More Panamanian than Colombian owl monkeys evidenced self-limited infection after the primary attack of either the Vietnam Smith or Uganda Palo Alto strain. The duration of the primary attacks and recrudescences were significantly shorter in Panamanian than in Colombian owl monkeys. Mean peak parasitemias during recrudescence were usually higher in Panamanian owl monkeys than in Colombian monkeys. Differences of infection parameters were probably attributable, in part, to geographical origin of the two monkey hosts and parasite strains.

Infection of Aotus azarae boliviensis monkeys with different strains of Plasmodium vivax

Sixty-seven splenectomized Aotus azarae boliviensis were infected with strains of Plasmodium vivax from Southeast Asia (2), New Guinea (2), North Korea (1), and Central America (3). Maximum parasitemias varied among the different strains, with the mean maximum parasitemia for the primary infection period being 16,200 per mm3. Animals previously infected with Plasmodium falciparum and Plasmodium malariae produced maximum parasitemias of 30,200 and 11,900 per mm3, respectively. Gametocytes infective to Anopheles freeborni mosquitoes were produced with 7 of the 8 strains examined.

Studies on the North Korean strain of Plasmodium vivax in Aotus monkeys and different anophelines

Twenty-two Aotus monkeys of different karyotypes were infected with the North Korean strain of Plasmodium vivax. Aotus lemurinus griseimembra animals from Colombia produced higher maximum parasitemias and more readily infected mosquitoes than did Aotus monkeys from Bolivia (K-VI) or Peru (K-V and K-X). Comparative feedings indicated that the most susceptible mosquito species was Anopheles stephensi, followed by An. gambiae, An. dirus, An. freeborni, An. quadrimaculatus, An. culicifacies, and An. maculatus.