Avaliação clínico-laboratorial de bovinos Nelore infectados experimentalmente com Trypanosoma vivax

Avaliaram-se as alterações clínico-laboratoriais de seis bezerros Nelore, de ambos os sexos, inoculados experimentalmente com 10(7) organismos viáveis de Trypanosoma vivax, isolados de bovinos da região de Poconé, Estado de Mato Grosso. Os animais foram observados diariamente, durante 30 dias, quanto aos parâmetros de temperatura retal, volume globular (VG), parasitemia, produção de anticorpos, coloração de mucosas, comportamento e apetite. Determinaram-se os níveis séricos de aspartato aminotransferase (AST), fosfatase alcalina (FA), gama glutamiltransferase (GGT), creatina kinase (CK), colesterol, uréia, creatinina, cálcio, fósforo e o perfil eletroforético das proteínas séricas aos 4, 8, 12, 16, 23 e 30 dias pós-inoculação (DPI). Durante os 6 meses seguintes, os animais foram observados semanalmente, avaliando-se a temperatura retal, o VG e a parasitemia. T. vivax foi evidenciado a partir do terceiro e quarto DPI em todos os bezerros e persistiu até o 30° DPI em cinco dos seis animais em estudo. Ocorreu um decréscimo significativo (p<0,05) do valor médio do VG (25%) aos dez DPI. Os animais não apresentaram qualquer alteração no quadro clínico, bem como na avaliação da bioquímica sérica durante o período experimental. A soroconversão ocorreu aos 6 e 8 DPI, permanecendo todos os animais soropositivos nos 30 dias experimentais. Bovinos nelores jovens, infectados experimentalmente com T. vivax, foram capazes de estabelecer um equilíbrio na relação hospedeiro-parasita.

Malaria at Humaita county, Amazonas state, Brazil: XVII - immune response in patients with Plasmodium falciparum according to gametocytes

Em agosto de 1983, os Autores, estudaram 36 doentes com infecção causada pelo Plasmodium falciparum e 14 indivíduos normais, nascidos na região de Humaitá, que nunca tiveram malária, sem esplenomegalia, com exame parasitológico de sangue e hemaglutinação passiva negativas. Todos eles foram submetidos à observação clínica completa, exame hematológico, exame parasitológico de sangue e tipagem de linfócitos. Os linfócitos foram isolados e congelados em nitrogênio líquido, para posterior tipagem pela formação de rosetas. Os doentes foram classificados em dois grupos de acordo com a presença (13 doentes), ou ausência (23 doentes) de gametócitos antes do tratamento. Houve predomínio de formas graves no grupo de doentes sem gametócitos. Os resultados mostraram diminuição do número de linfócitos T em ambos os grupos de doentes, com ou sem gametócitos antes do tratamento, enquanto que o número de linfócitos B foi normal apenas no grupo de doentes com gametócitos. Essas observações, assim como as que foram relatadas pelos Autores anteriormente, permitem associar a presença de gametócitos circulantes com o número normal de células B em doentes com formas leves de malária causada pelo Plasmodium falciparum.

Organ tropism during the acute and chronic phases of Trypanosoma cruzi infection in BALB/c mice

The aim of the present study was to investigate the presence of Trypanosoma cruzi in the heart, liver, lung, and kidneys, using hemoculture and PCR analysis, of mice infected with different parasite strains during the acute and chronic phases of infection. Parasitemia curves revealed strain-specific biological behaviors. For the Y and JLP strains, the acute phase of infection started at days six and ten post-infection, parasitemia peaked at days seven and 15 post-infection, the chronic phase started at days nine and 28 post-infection, and animals started dying at days 19 and 120 post-infection, respectively. When the two strains were compared, the JLP strain exhibited reduced and slower replication rates associated with a delayed peak of parasitism and reduced parasite burdens. However, parasites were detected in all studied organs using PCR analysis. The capacity of both strains to infect different organs likely influences disease pathogenesis.

Babesia spp. infection in Boophilus microplus engorged females and eggs in São Paulo State, Brazil

Babesia spp. infections were investigated in Bos taurus x Bos indicus dairy cows and calves and in Boophilus microplus engorged female ticks and eggs. Blood samples and engorged female ticks were collected from 25 cows and 27 calves. Babesia spp. was detected in ticks by microscopic examination of hemolymph of engorged female and by squashes of egg samples. Cattle infection was investigated in blood thin smears and by DNA amplification methods (PCR and nested PCR), using specific primers for Babesia bovis and Babesia bigemina. Merozoites of B. bovis (3 animals) and B. bigemina (12 animals) were detected exclusively in blood smears of calves. DNA amplification methods revealed that the frequency of B. bigemina infection in calves (92.6%) and in cows (84%) and of B. bovis in calves (85.2%) and in cows (100%) did not differ significantly (P > 0.05). Babesia spp. infection was more frequent in female ticks and eggs collected from calves (P < 0.01) than from cows, especially in those which had patent parasitemia. Hatching rates of B. microplus larvae were assessed according to the origin of engorged females, parasiternia of the vertebrate host, frequency and intensity of infection in engorged female tick, and frequency of egg infection. Hatching rate was lower in samples collected from calves (P < 0.01) than from cows, and in those in which Babesia spp. was detected in egg samples (P < 0.01). Published by Elsevier B.V.

Toxoplasma gondii in experimentally infected Bos taurus and Bos indicus semen and tissues

Dezoito bovinos foram inoculados com Toxoplasma gondii e distribuídos aleatoriamente em três grupos de seis bovinos cada: GI (2,5x10(5) oocistos da cepa P), GII (5,0x10(6) taquizoítos da cepa RH) e GIII (controle). Exames clínicos, sorológicos e parasitêmicos foram realizados. Pesquisas do parasito, por meio da bioprova e pela técnica de Reação em Cadeia pela Polimerase (PCR), foram realizadas no sêmen e em fragmentos de musculatura esquelética, linfonodos, cérebro, retina, baço, fígado, pulmão, testículo, epidídimo e vesícula seminal. Amostras de sangue e sêmen foram colhidas nos dias -2, -1, 1, 3, 5, 7, 14 e, semanalmente, até o 84º dia pós-infecção (DPI). Os bovinos inoculados (GI e GII) apresentaram hipertermia do 3º ao 16º DPI. Anticorpos contra T. gondii foram detectados (IFI) no 5º DPI (1:16), em ambos grupos inoculados (oocistos e taquizoítos), atingindo picos de 1:4096 no 7º DPI. Surtos parasitêmicos ocorreram em todos os bovinos infectados, principalmente do 7º ao 28º DPI, independente da cepa e inóculo utilizados. O bioensaio revelou a presença do parasito em amostras seminais dos bovinos infectados com oocistos (GI) e taquizoítos (GII), em diversas datas experimentais, entre o 7º e 84º DPI. Parasitismo tissular por T. gondii foi diagnosticado por meio da bioprova e pela técnica da PCR, em vários fragmentos de tecidos e/ou órgãos. Os achados sugerem a possibilidade da ocorrência da transmissão sexual do T. gondii na espécie bovina.

Clínica e hematologia de Bos indicus, Bos taurus e Bubalus bubalis inoculados com oocistos de Toxoplasma gondii (Apicomplexa: Toxoplasmatinae)

Três animais de cada espécie (Bos indicus, Bos taurus e Bubalus bubalis) foram inoculados, via oral, com 2,0 x 10(5) oocistos de Toxoplasma gondii. Seis outros animais, dois de cada espécie, foram mantidos como testemunhas. As alterações clínicas surgidas a partir do 3º dia após inoculação (DAI) foram: hipertermia, taquicardia, taquipnéia, anorexia, prostração, corrimento nasal e lacrimejamento. Estes sinais foram mais evidentes nos taurinos, espécie que apresentou, ainda, diarréia, fotofobia e conjuntivite. Foi possível isolar T. gondii da corrente sangüínea em todas as espécies. Nos taurinos, a partir do 5º DAI até o final do experimento, o parasito foi isolado de todas as amostras de sangue colhidas semanalmente, com exceção do 14º, 35º e 63º DAI. Os bubalinos apresentaram parasitemia no 7º, 14º, 35º e 70º DAI e os zebuínos apenas no 7º e 28º DAI, correspondendo aos picos de temperatura, em todas as espécies, sendo mais evidente em taurinos. Os parâmetros clínico-laboratoriais demonstraram que os taurinos foram mais sensíveis ao T. gondii do que os zebuínos e estes não diferiram significativamente dos bubalinos, que tiveram aparente normalidade clínico-laboratorial.

Description of the gamonts of a small species of Hepatozoon sp (Apicomplexa, Hepatozoidae) found in Crotalus durissus terrificus (Serpentes, Viperidae)

A small species of the genus Hepatozoon found in a specimen of Crotalus durissus terrificus from the Botucatu region, São Paulo State, Brazil is described. The morphologic alterations induced in the snake's erythrocytes by the presence of this parasite are described. Morphology and morphometric analyses were performed using the Qwin Lite 2.5 computerized image analysis system (Leica). The Hepatozoon possessed a small and short body (8.1+/-0.5 mum long and 3.8+/-0.4 mum wide), with round extremities. The cytoplasm varied from pale blue to basophilic and had no granulations. Its nucleus was large, occupied a large area of the cytoplasm, and was irregular in shape and not condensed. Despite its small size, this parasite induced important changes in the host cell. Total parasitemia observed was 56.6%.

Experimental Trypanosoma evansii infection in South American coati (Nasua nasua): hematological, biochemical and histopathological changes

The course of an experimental Trypanosoma evansi infection in coatis (Nasua nasua, carnivora, Procyonidae) was followed for 262 days. Hematological analysis of the infected coatis revealed a marked decline in hemoglobin, packed-cell volume, and total erythrocyte count. An intense anemia followed the first wave of parasitemia and persisted until the end of the experimental period. Biochemical analysis showed increased serum levels of alanine aminotransferase and aspartate aminotransferase and decreased albumin. The main histopathological features consisted of myocarditis with the presence of degenerate cardiac fibers and meningoencephalitis. This study has shown that coatis infected with T. evansi develop a chronic disease. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Antiplasmodial activity of aryltetralone lignans from Holostylis reniformis

Extracts from Holostylis reniformis were tested in vivo against Plasmodium berghei and in vitro against a chloroquine-resistant strain of Plasmodium falciparum. The hexane extract of the roots was the most active, causing 67% reduction of parasitemia in vivo. From this extract, six lignans, including a new (7 ' R,8S,8 ' S)-3 ',4 '-methylenedioxy-4,5-dimethoxy-2,7 '-cyclolignan-7-one, were isolated and tested in vitro against P. falciparum. The three most active lignans showed 50% inhibitor concentrations of <= 0.32 mu M. An evaluation of minimum lethal dose (30%) values showed low toxicity for these lignans in a hepatic cell line (Hep G2A16). Therefore, these compounds are potential candidates for the development of antimalarial drugs.

Experimental toxoplasmosis in broiler chicks

To evaluate chicken toxoplasmosis both as an economic and a public health subject, 84 broiler chicks of a commercial strain, 30 days old, were distributed into seven groups of 12 birds (three replications of four chicks) experimentally infected with three developing T. gondii stages of the P strain as follows: tachyzoites. intravenous (two groups: 5.0 x 10(5) and 5.0 x 10(6)), cysts, per os (two groups: 1.0 x 10(2) and 1.0 x 10(3)) and oocysts, per os (three groups: 5.0 x 10(2), 5.0 x 10(3) and 5.0 x 10(4)). Twelve chicks received only a placebo (control group). During the next 30 days the following parameters were estimated: productivity (weight gain and feed conversion), clinical signs, including rectal temperature and parasitemia (bioassay). No clinical signs suggesting toxoplasmosis were seen and no statistical differences on productivity standards were found in comparison between inoculated and control chicks. However, fowls inoculated with tachyzoites and oocysts occasionally showed hyperthermia. Some haematological changes were detected in fowls inoculated with T. gondii. Anatomo-histopathological changes were not observed. From 14 parasitemias detected, 35.7% appeared on the 5th day after inoculation and 57.1% of them resulted from oocysts inoculation. After 30-35 days all birds were slaughtered: fragments from 12 organs or tissues from each of them were subjected to artificial peptic digestion and after that injected into T. gondii antibody-free mice (IIFR). T. gondii was detected in brain (12), pancreas (five), spleen (five), retina (five), kidney (two), heart (four), proventriculus (three), liver (two), intestine (two), lung (one), and skeletal muscle (one). Similar to observations with parasitemia, from 42 T. gondii isolations, 59.5% came from chicks which had received oocysts. It can thus be inferred that the developing form, expelled by cats, is the most important for T. gondii chicken infection and that brain is the most infected organ in birds. Attention must be paid to the potential importance of chicken meat in public health, since T. gondii was isolated from skeletal and heart muscles. (C) 1997 Elsevier B.V. B.V.

Acquisition and transmission of Hepatozoon canis (Apicomplexa: Hepatozoidae) by the tick Amblyomma ovale (Acari: Ixodidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Experimental infection of bovines with oocysts of Toxoplasma gondii

Calves aged 3 mth were readily infected with oocysts and cysts of Toxoplasma gondii administered by the oral route. Fever, respiratory distress, nasal discharge, and hyperemia of the conjunctivas were the most significant clinical signs noted in the infected animals. Parasitemia was demonstrated in all infected calves. It occurred on different days and up to 62 days after the infection. Toxoplasma was demonstrated in tissues of all infected calves, and the organ most frequently parasitized was the lymph node. Parasitism of the retina was demonstrated in 2 calves. All infected animals had antibody against T. gondii in their serum. The Sabin-Feldman dye test and the indirect immunofluorescent test were both useful in detecting antitoxoplasma antibody.

Avaliação clínica e hematológica em bezerros Nelore infectados experimentalmente com isolados de Babesia bigemina das regiões Sudeste, Nordeste e Norte do Brasil

A comparative study was made regarding the clinical and hematological alterations caused by isolates of Babesia bigemina from southeastern, northeastern and northern Brazil in experimentally infected Nelore calves. Eighteen calves between 7 and 9 months of age, without antibodies against Babesia sp and raised free from ticks, were used. Three animals were previously inoculated with 2.0×109 parasitic erythrocytes (PE) for each stabilate. The other 15 calves were subdivided into three groups, with five animals each, that were subinoculated with 1.0×1010 PE of the respective isolates. The clinical and hematological alterations were evaluated by the determination of parasitaemia, haemogram, plasmatic fibrinogen, reticulocyte count, descriptive analysis of the bone marrow and erythrocytic osmotic fragility, for 30 days, totalizing seven moments of observation. The follow-up of the immunological response by the indirect fluorescent antibody test was carried out daily until the 10th day after inoculation (DAI) and after that, on the 15th, 20th, 25th and 30th DAI. A mild clinical manifestation of the disease was observed. The laboratory findings revealed low levels of parasitaemia; decrease of the erythrogram values; absence of reticulocytes, initial decrease in the total count of leukocytes, neutrophils and lymphocytes with a posterior elevation of the number of these cells; hypercellularity of the erythrocytic series and decrease of the myeloid: erythroid relation which was more accentuated between the 8th and 12th DAI, and an increase of the erythrocytic osmotic fragility in the groups inoculated with the Southeast and Northeast isolates. None of the three isolates of B. bigemina gave rise to the clinical characteristic form of the disease, although they induced an humoral immune response.

Toxoplasma gondii in semen of experimentally infected swine

Eight reproductive boars were divided into three groups and inoculated with Toxoplasma gondii [GI (n=3) 1.5×104 oocysts strain P; GII (n=3) 1.0×106 tachyzoites strain RH; and GIII (n=2) non-inoculated control]. Clinical, hematological, parasitemia and serological tests and studies of the parasite in the semen through bioassay and PCR, and in reproductive organs (Bioassay and immunohistochemical analyses) were conducted to evaluate the toxoplasmic infection. Blood and semen were collected on day -2, -1, 1, 3, 5, 7, 9, 11, 14 and weekly up to 84 days post-inoculation (DPI). No clinical or hematimetric alteration was observed in the boars. Parasitemia was detected in one boar inoculated with oocysts at the 7th DPI and in another boar infected with tachyzoites (GII) at the 3rd and 49 th DPI. Serological tests revealed antibodies against T. gondii in animals inoculated with oocysts or tachyzoites at the 7th DPI with dilutions of 1:256 and 1:64, which reached peaks of 1:4096 at day 11 and 9, respectively. The bioassays revealed the presence of the parasite in semen samples of a boar inoculated with oocysts (GI) at 3, 49 and 56 DPI and from two boars infected with tachyzoites (GII), one animal at 5 and two animals at 49 days DPI. Mice inoculated with semen from the control group (GIII) remained serologically negative. PCR analysis showed T. gondii DNA in the semen of Boar 1 and Boar 3 inoculated with tachyzoites and oocysts, respectively. The immunohistochemical tests showed T. gondii in the reproductive organs of Boar 1 and Boar 2, inoculated with tachyzoites and oocysts, respectively. These findings suggest the possible occurrence of venereal transmission of T. gondii in swine.

Frequency of the HFE C282Y and H63D polymorphisms in Brazilian malaria patients and blood donors from the Amazon region

Malaria is an endemic parasitosis and its causitive agent, Plasmodium, has a metabolism linked to iron supply. HFE is a gene with the polymorphisms C282Y and H63D, which are associated with a progressive iron accumulation in the organism leading to a disease called hereditary hemochromatosis. The aim of the present study was to determine the allelic and genotypic frequencies of the HFE gene polymorphisms in malaria patients and blood donors from the Brazilian Amazon region. We screened 400 blood donors and 400 malaria patients for the HFE C282Y and H63D polymorphisms from four states of the Brazilian Amazon region by polymerase chain reaction and restriction fragment length polymorphism analysis. We did not find any C282Y homozygous individuals, and the only five heterozygous individuals detected were from Pará State. The most frequent genotype in the North region of Brazil was the H63D heterozygote, in both study groups. Our results contribute to the concept that the Brazilian Amazon region should not be regarded as a single entity in South America. These polymorphisms did not influence the symptoms of malaria in the population studied, as neither severe signs nor high parasitemia were observed. Therefore, different hereditary hemochromatosis diagnostic and control measures must be developed and applied within its diverse locations. Investigations are currently being carried out in our laboratory in order to determine the importance of the coexistence of hereditary hemochromatosis in patients affected by parasitic diseases, such as malaria. ©FUNPEC-RP.