Estudio de Fiebre Amarilla en primates en áreas de brote de los departamentos de San Pedro y Central del Paraguay / Study of Yellow Fever in primates in outbreaks areas of the departments of San Pedro and Central in Paraguay

La Fiebre Amarilla (FA) es una de las más importantes zoonosis que afecta a poblaciones humanas. La FA silvestre es imposible de ser erradicada, manteniéndose activa en zonas tropicales en África y Sudamérica. Todas las especies de primates son susceptibles y se consideran reservorios en el medio silvestre. La mortalidad es baja, se desconoce su valor con precisión, sin embargo existen epizootias con alta mortalidad, en humanos varía entre 20-50%. El objetivo de este trabajo fue buscar evidencias de FA en primates capturados en áreas de brote de FA de los departamentos de San Pedro y Central del Paraguay mediante la técnica de Neutralización por reducción de placas para FA cepa vacunal 17 D. Los resultados en los 35 primates estudiados fueron negativos, quizás por lo tardío del momento en la toma de muestras y bajo número de primates capturados.

Yellow Fever (YF) is one of the most important zoonotic diseases affecting human population. It is impossible to eradicate wild YF remaining active in tropical zones of Africa and South America. All species of primates are susceptible and are considered reservoirs in wild regions. Mortality is low and its precise value is unknown though there are epizootics with high mortality rates and in humans varies between 20-50%. The objective of this study was to search for evidence of YF in primates caught in YF outbreaks areas of the departments of San Pedro and Central in Paraguay through the neutralization technique by plates reduction for YF vaccine strain 17 D. The results in the 35 primates studied were negative, perhaps because of the lateness of the time sampling and the low number of captured primates.

Experimental treatment of chronic Trypanosoma cruzi infection in mice with 2-n-propylquinoline.

It was reported previously that 2-n-propylquinoline was active against the epimastigote form of Trypanosoma cruzi. The effects of oral treatments with benznidazole and 2-n-propylquinoline were evaluated in Balb/c mice infected with T. cruzi chronically. The reference drug and 2-n-propylquinoline were administered 60 days post-infection for 30 days at 25 mg/mL. At 35 days post-treatment, the serological tests (ELISA) of the 2-n- propylquinoline-treated mice were significantly different from the controls (p = 0.01) and the benznidazole-treated mice (p = 0.03), while this was not the case at 85 days post-treatment. These results are encouraging for continuing the investigation of other analogues of 2-n-propylquinoline in experimental chronic Chagas' disease.

Efficacy of the bisbenzylisoquinoline alkaloids in acute and chronic Trypanosoma cruzi murine model.

We have shown previously that daphnoline and cepharanthine are active against Trypanosoma cruzi and inhibited trypanothione reductase. The effects of oral treatments with daphnoline, cepharanthine and benznidazole were examined in Balb/c mice infected with T. cruzi acutely and chronically. In acute infections, parasitaemia was significantly reduced in the daphnoline-treated mice compared with controls and benznidazole-treated mice. The parasitological cure rate was increased in mice treated with daphnoline. Fifty days after infection, the negative serological response in both models was significantly different for the three tested drugs. Daphnoline showed the highest negative serological rate (48%). In chronically infected mice treated with daphnoline, we were unable to detect parasites in 70% of mice. The results obtained of oral treatment of daphnoline suggest that this bisbenzylisoquinoline may be useful in the treatment of acute and chronic Chagas' disease. This was not seen with cepharanthine, an excellent trypanothione reductase inhibitor.

Local and systemic cytokine expression during experimental chronic Trypanosoma cruzi infection in a Cebus monkey model.

Cebus apella is an acceptable model for chronic chagasic cardiomyopathy (CCC), since it is possible to experimentally induce cardiac lesions after 1 year of Trypanosoma cruzi infection. The T. cruzi Y strain, shown previously to produce CCC in C. apella monkeys, was used to experimentally infect 10 monkeys. Parasitological, serological and clinical parameters were monitored during a 19-month follow-up, and systemic cytokine responses were assessed sequentially in five monkeys selected according to the differential parasitemia pattern exhibited. Ten additional monkeys, infected with the same strain for 5, 10 and 12 years, were analysed cross-sectionally. Three monkeys/time point and one uninfected control animal were sacrificed for gross pathology, histology, presence of parasites, and local cytokine gene expression. Elevated expression of interleukin (IL)-4 was observed throughout the study in monkeys that had persistent, high parasitemias, whereas a high level of interferon (IFN)-gamma was seen in monkeys that controlled parasitemias soon after infection. Chronically infected monkeys expressed a nonpolarized, Th0-type response. Cardiac tissue collected from a monkey that succumbed to acute infection had elevated levels of proinflammatory cytokine [IL-1beta, IL-6, tumour necrosis factor-alpha] and interstitial cell adhesion molecule (ICAM)-1, platelet-derived growth factor (PDGF)-alpha, transforming growth factor (TGF)-beta and IL-10 transcripts. Cytokine production in cardiac tissue of chronically infected monkeys was also characterized by elevated expression of ICAM-1, PDGF-alpha and TGF-beta, which correlated with the detection of T. cruzi DNA by polymerase chain reaction.

[Intraocular involvement of Chagas disease (American trypanosomiasis). Studies in Paraguay/South America]. / Beteiligung der Chagas-Krankheit (Amerikanische Trypanosomiasis) am inneren Auge. Untersuchungen in Paraguay/Südamerika.

BACKGROUND: In Central and South America, Chagas' disease is of great epidemiologic importance. The epidemiologic agent is represented by Trypanosoma cruzi, a monocellular parasite, instrumental in human infection is the presence of vectors, which are various species of hematophagous bugs. The eye is one of the most important entrance sites of the parasite, and relatively little information about the relationship between Chagas' disease and eye complications is available. PATIENTS AND METHODS: We examined 79 chagasic patients in order to detect changes in the retina. As a control group, we examined 48 patients with negative serology within the same age range and from the same regions. For every patient we completed a routine ophthalmologic examination, with inspection of the retina using direct and indirect ophthalmoscopy. RESULTS: In most of the chagasic patients, the ocular fundus was unobtrusive; in only 6 out of 79 cases (7.6%) we did observe small parafoveolar retinal pigment epithelium defects and in 1 case (1.3%) distinct pigment epithelium atrophy of the posterior pole. No comparable findings were observed in the control group. CONCLUSION: Compared with the examination results of the control group, in the patients with intermediate and chronic Chagas' disease we observed an accumulation of retinal pigment epithelium defects, which, however, did not cause a significant loss of vision.

The effect of bisbenzylisoquinoline alkaloids on Trypanosoma cruzi infections in mice.

Five bisbenzylisoquinoline (BBI) alkaloids, curine, cycleanine, isotet:andrine, limacine and pheanthine were tested for trypanocidal activity in C 3H He mice infected with Y or CL strain of Trypanosoma cruzi. The activity was compared with the baseline drug, benznidazole. Oral treatment was more effective with curine at 10 mg/kg or with cycleanine at 2 mg/kg daily for 10 days in mice infected with Y or CL strain. In these groups, the parasitemias were negative after 5-7 weeks after inoculation and mortality time 50 (MT(50)) was significantly higher than untreated mice. Benznidazole was effective in mice infected with CL strain but not in mice infected with Y strain. The other BBI showed a relative efficacy against both strains. The effect of BBI alkaloids could be due to a blocking of the Ca2+ channel for the regulation of T. cruzi infectivity to invade host cells or their selective immunosuppressive properties.

In vivo efficacy of oral and intralesional administration of 2-substituted quinolines in experimental treatment of new world cutaneous leishmaniasis caused by Leishmania amazonensis.

The antileishmanial efficacies of 2-n-propylquinoline, chimanines B and D, 2-n-pentylquinoline, 2-phenylquinoline, 2-(3,4-methylenedioxyphenylethyl) quinoline, and two total alkaloidal extracts of Galipea longiflora were evaluated in BALB/c mice infected with Leishmania amazonensis or Leishmania venezuelensis. Animals were treated for 4 to 6 weeks postinfection with a quinoline by the oral route at 50 mg/kg of body weight twice daily for 15 days or by five intralesional injections at intervals of 4 days with a quinoline at 50 mg/kg of body weight. The reference drug, N-methylglucamine antimonate (Glucantime), was administered by subcutaneous or intralesional injection (regimens of 14, 28, or 56 mg of pentavalent antimony [Sbv] per kg of body weight daily). Twice-daily oral treatment with chimanine B at 50 mg/kg resulted in a decrease in lesion weight by 70% (P < 0.001) and a decrease in the parasite loads by 95% (P < 0.001). Five injections of chimanine B at intervals of 4 days reduced the lesion weight by 74% and the parasite loads in the lesion by 90% compared with the values for the group of untreated mice. Subcutaneous administration of N-methylglucamine antimonate at 28 mg of Sbv kg per day for 15 days reduced the parasite burden by 95% (P < 0.001), and five intralesional injections at the same concentration reduced the parasite burden by 96% (P < 0.001). Other 2-substituted quinolines, 2-n-propylquinoline administered by the oral and intralesional routes, 2-phenylquinoline administered by the oral route, 2-n-pentylquinoline administered by intralesional injection, and two total alkaloidal extracts of G. longiflora administered by the oral route, had intermediate effects. These findings suggest that chimanine B may be chosen as a lead molecule in the development of oral therapy against leishmaniasis.

Cardiomyopathy in Cebus apella monkeys experimentally infected with Trypanosoma cruzi.

Twenty four Cebus apella monkeys were studied as a biological model for the cardiac chronic form of Chagas' disease. Twelve were inoculated with Trypanosoma cruzi trypomastigotes, seven with the Brazilian Y strain and five with the Argentinian RA strain. Twelve monkeys were uninfected controls. The following parameters were studied: body weight, body temperature, direct parasitemia, xenodiagnosis, specific antibodies by IFA, clinical chemistry, hematology, ECG and chest X-ray. Three monkeys infected with Y strain were sacrificed at 4 months and 4 monkeys at 12 months after inoculation. Monkeys inoculated with RA strain were sacrificed at 48 months. Direct parasitemia was positive within a week after inoculation in all monkeys. Xenodiagnosis was positive until 49.0 +/- 3.0 and 79.0 +/- 6.0 weeks p.i. for Y and RA strains, respectively. In all inoculated monkeys an increase in antibody titers was detected within 3 weeks after inoculation. In all monkeys inoculated with the Y strain and 3/5 with the RA strain abnormal ECGs were observed within 1 or 2 weeks p.i., becoming more severe in the chronic phase. Y strain inoculated monkeys sacrificed at 4 months presented only a slight concentric hypertrophy of the heart left ventricle. Those sacrificed at 12 months had concentric left ventricle hypertrophy and 3/4 had an aneurism of the apex. Four out of 5 RA strain inoculated monkeys had an enlarged, flaccid heart; 3/5 aneurism of the apex and 2/5 concentric hypertrophy of the left ventricle.(ABSTRACT TRUNCATED AT 250 WORDS)

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)

Body measurements, hematology, and serum chemistry values of the adult Cebus apella monkey.

Body measurements, hematology, and serum chemistry values were studied in 40 captured male and female Cebus apella monkeys. Some significant dimorphism with male predominance was found. Significant differences were also found for hemoglobin and red cell volume between males and females. Differential white blood cell counts indicated a marked predominance of lymphocytes and high values of gamma globulin in both sexes.