Postnatal zinc deficiency due to giardiasis disrupts hippocampal and cerebellar development.

BACKGROUND: Giardiasis and zinc deficiency have been identified as serious health problems worldwide. Although Zn depletion is known to occur in giardiasis, no work has investigated whether changes occur in brain structures. METHODS: Three groups of gerbils were used: control (1), orogastrically inoculated on day 3 after birth with trophozoites of two isolates of Giardia intestinalis (HGINV/WB) group (2 and 3). Estimates were made at five ages covering: establishment of infection, Giardia population growth, natural parasite clearance and a post-infection age. QuantiChrome zinc assay kit, cresyl violet staining and TUNEL technique were used. RESULTS: A significant decrease (p<0.01) in tissue zinc was observed and persisted after infection. Cytoarchitectural changes were observed in 75% of gerbils in the HGINV or WB groups. Ectopic pyramidal neurons were found in the cornus ammonis (CA1-CA3). At 60 and 90 days of age loss of lamination was clearly visible in CA1. In the dentate gyrus (DG), thinning of the dorsal lamina and abnormal thickening of the ventral lamina were observed from 30 days of age. In the cerebellum, we found an increase (p<0.01) in the thickness of the external granular layer (EGL) at 14 days of age that persisted until day 21 (C 3 ± 0.3 µm; HGINV 37 ± 5 µm; WB 28 ± 3 µm); Purkinje cell population estimation showed a significant decrease; a large number of apoptotic somas were observed scattered in the molecular layer; in 60 and 90 days old gerbils we found granular cell heterotopia and Purkinje cell ectopia. The pattern of apoptosis was different in the cerebellum and hippocampus of parasitized gerbils. CONCLUSION: The morphological changes found suggest that neuronal migration is affected by zinc depletion caused by giardiasis in early postnatal life; for the first time, the link between giardiasis-zinc depletion and damaged brain structures is shown. This damage may explain the psychomotor/cognitive delay associated with giardiasis. These findings are alarming. Alterations in zinc metabolism and signalling are known to be involved in many brain disorders, including autism.

Age range implications of rats over Strongyloides venezuelensis infection.

OBJECTIVE: To evaluate the dynamics of S. venezuelensis infection in Wistar rats of different age ranges. DESIGN: Thirty-five (n = 35, 7 per group) male Wistar rats were distributed according to age into five groups: 2, 3, 6, 12 and 18 months old (mo). The rats were infected by S. venezuelensis and eggs per gram of feces (EPG) were measured at 3, 9, 15 and 21 days post-infection (dpi). All animals were killed at 21 dpi, thymus, lungs and small intestines were removed, and relative weight calculated. The adult worms recovered from the small intestines and blood cells were counted. RESULTS: Rats in advanced age presented higher parasite oviposition at 9 dpi and posterior reduction of EPG, while young rats still showed higher oviposition at 15 dpi and 21 dpi. At 12 and 18 mo, the rats had greater number of adult worms, which with low fecundity, eosinophilia and least concentration of monocytes. The fecundity of worms was more expressive in young rats. A strong correlation was observed between age and EPG at 9 dpi (R = 0.72, p < 0.0001), at 15 (R = -0.66, p < 0.0001) and at 21 dpi (R = -0.65, p < 0.0001), as well as age and numbers of worms at 21 dpi (R = 0.74, p < 0.0001). The relative weight of the thymus, lungs and small intestines were higher in rats at 2 and 3 mo in comparison to the older groups of rats. CONCLUSIONS: Aging process interfered on host-parasite relationship and changed the dynamics of infection of S. venezuelensis in Wistar rats.

Neospora caninum DNA distribution in tissues of gerbils as experimental models of chronic neosporosis / [Distribuição do DNA de Neospora caninum em tecidos de gerbilos como modelos experimentais de neosporose crônica]

Neospora caninum is the main etiologic agent of neosporosis in domestic animals and its pathogenesis comprises two characteristic phases: acute and chronic. Rodents are used as experimental models to mimic acute and chronic bovine neosporosis. In this study, we inoculated a total of 27 female gerbils, with different doses of N. caninum tachyzoites aiming to induce chronic disease. DNA was extracted from different organs of each animal after spontaneous death or euthanasia. Encephalic tissues were submitted to a highly sensitive real time PCR aiming to detect chronically infected animals. All the other samples were submitted to standard PCR. A total of 11 gerbils died due to acute neosporosis, as confirmed by N. caninum DNA detection in organs. 5x103 tachyzoites/mL of N. caninum was the dosage of antigen that can induce chronic infection in gerbils. In the encephalon sections of some animals that showed clinical signs of persistent infection, we found 70% positive for the anterior encephalon section, suggesting this area as preferential for cyst formation. Therefore, we determined the doses of tachyzoites that cause acute or chronic infection and detection of positive tissues, preferably, systemic organs during acute and encephalon in chronic phases.(AU)

Neospora caninum é o principal agente etiológico da neosporose em animais domésticos, e sua patogênese compreende duas fases características: aguda e crônica. Roedores são usados como modelos experimentais para simular neosporose bovina aguda e crônica. Neste estudo, foi inoculado um total de 27 gerbilos, fêmeas, com diferentes doses de taquizoítos de N. caninum, visando induzir doença crônica. O DNA foi extraído de diferentes órgãos de cada animal após a morte espontânea ou a eutanásia. Os tecidos encefálicos foram submetidos à PCR em tempo real de alta sensibilidade para detecção de animais com infecção crônica. Todas as outras amostras foram submetidas à PCR padrão. Um total de 11 gerbilos morreu devido à neosporose aguda, como confirmado pela detecção de DNA de N. caninum nos órgãos. A dosagem de antígeno que pode induzir infecção crônica foi de 5x103 taquizoítos/mL de N. caninum. Em seções do encéfalo de alguns animais, que apresentaram sinais clínicos de infecção persistente, encontraram-se 70% de positividade para a seção do encéfalo anterior, sugerindo essa área como preferencial para a formação de cisto. Assim, foram determinadas,, em gerbilos, as dosagens de taquizoítos capazes de induzir infecção crônica ou aguda, bem como foram detectados tecidos positivos, preferencialmente, em órgãos sistêmicos, na fase aguda, e no encéfalo, na crônica.(AU)

Oxyurid nematodes of pet rodents in Slovakia - a neglected zoonotic threat / Nematódeos oxiurídeos de roedores de estimação na Eslováquia - uma ameaça zoonótica negligenciada

Abstract The role of rodents as reservoirs of helminths of public health importance is not well known. The zoonotic potential of Syphacia spp. has been confirmed; therefore, the study aimed to estimate the occurrence of oxyurid nematodes in small rodents from pet shops and breeding clubs in Slovakia. Fecal samples of 586 pet rodents kept in 133 cages were collected between 2016 and 2018 and examined by Faust´s flotation method. Four species of oxyurid nematodes, Syphacia muris, S. obvelata, Aspiculuris tetraptera and Paraspidodera uncinata were detected. A. tetraptera was found in the faecal samples of all rodent species included in this survey. The number of positive boxes varied from 5.4% in hamsters to 70.0% with mice. The prevalence of Syphacia muris was highest in Mongolian gerbils where up to 75.0% boxes were positive; S. obvelata was found in 26.7% of boxes with mice, 25.0% of boxes with Mongolian gerbils and 3.2% of boxes with rats. The high prevalence of Syphacia spp. in all animal species points out the infection risk for humans. Animals offered for sale are often in close contact with human beings; therefore they should be regularly tested for parasites and then effectively dewormed.

Resumo O papel dos roedores como reservatórios de helmintos de importância para a saúde pública não é bem conhecido. O potencial zoonótico de Syphacia spp. foi confirmado; portanto, o estudo teve como objetivo estimar a ocorrência de nematóides oxiurídeos em pequenos roedores de pet shops e clubes de reprodução na Eslováquia. Amostras fecais de 586 roedores mantidos em 133 gaiolas foram coletadas entre 2016 e 2018 e examinadas pelo método de flotação de Faust. Foram detectadas quatro espécies de nematódeos oxiurídeos, Syphacia muris, S. obvelata, Aspiculuris tetraptera e Paraspidodera uncinata, A. tetraptera foi encontrado nas amostras fecais de todas as espécies de roedores incluídas nesta pesquisa. O número de gaiolas positivas variou de 5,4% em hamsters a 70,0% em camundongos. A prevalência de Syphacia muris foi maior nos gerbilos da Mongólia, onde até 75,0% das gaiolas foram positivas; S. obvelata foi encontrada em 26,7% das gaiolas com camundongos, 25,0% das gaiolas com gerbilos da Mongólia e 3,2% das gaiolas com ratos. A alta prevalência de Syphacia spp. em todas as espécies animais aponta o risco de infecção para os seres humanos. Animais oferecidos para venda estão frequentemente em contato próximo com seres humanos; portanto, eles devem ser regularmente testados quanto a parasitas e, então, efetivamente desparasitados.

Oxyurid nematodes of pet rodents in Slovakia - a neglected zoonotic threat.

The role of rodents as reservoirs of helminths of public health importance is not well known. The zoonotic potential of Syphacia spp. has been confirmed; therefore, the study aimed to estimate the occurrence of oxyurid nematodes in small rodents from pet shops and breeding clubs in Slovakia. Fecal samples of 586 pet rodents kept in 133 cages were collected between 2016 and 2018 and examined by Faust´s flotation method. Four species of oxyurid nematodes, Syphacia muris, S. obvelata, Aspiculuris tetraptera and Paraspidodera uncinata were detected. A. tetraptera was found in the faecal samples of all rodent species included in this survey. The number of positive boxes varied from 5.4% in hamsters to 70.0% with mice. The prevalence of Syphacia muris was highest in Mongolian gerbils where up to 75.0% boxes were positive; S. obvelata was found in 26.7% of boxes with mice, 25.0% of boxes with Mongolian gerbils and 3.2% of boxes with rats. The high prevalence of Syphacia spp. in all animal species points out the infection risk for humans. Animals offered for sale are often in close contact with human beings; therefore they should be regularly tested for parasites and then effectively dewormed.

Meriones unguiculatus infected by Haemonchus contortus: evaluation of different experimental protocols.

Many important studies on resistance reversion, anthelmintic efficacy and, especially, new molecules with antiparasitic effects are performed in laboratories using gerbils (Meriones unguiculatus) as the experimental model. This study aimed to evaluate the use of corticosteroids (dexamethasone and methylprednisolone acetate) in gerbils experimentally infected with different doses of infective larvae (sheathed or exsheathed) of Haemonchus contortus. In the first experiment, 28 gerbils were divided into seven groups infected by 2-6 × 103 larvae, with or without immunosuppression using corticosteroids. In the second experiment, eight gerbils were divided into two groups infected by 2 × 103 sheathed or exsheathed larvae. For the third assay, seven immunosuppressed gerbils were infected with 2 × 103 sheathed larvae and were killed 15 days post infection (PI). The highest number of parasites was recovered from methylprednisolone-immunosuppressed animals. We observed red and white blood cell alterations and biochemical parameters in infected animals that had undergone immunosuppression with methylprednisolone. We highlight that in the first and second experiments a satisfactory number of worms was recovered using sheathed larvae and immunocompetent animals. When exsheathed larvae were used, the number of worms recovered was unsatisfactory. A considerable larval burden was recovered from immunosuppressed gerbils 15 days PI, and body weight did not influence establishment of larvae.

In vitro nematicidal effect of Chenopodium ambrosioides and Castela tortuosa n-hexane extracts against Haemonchus contortus (Nematoda) and their anthelmintic effect in gerbils.

The in vitro nematicidal effect of Chenopodium ambrosioides and Castela tortuosa n-hexane extracts (E-Cham and E-Cato, respectively) on Haemonchus contortus infective larvae (L3) and the anthelmintic effect of these extracts against the pre-adult stage of the parasite in gerbils were evaluated using both individual and combined extracts. The in vitro confrontation between larvae and extracts was performed in 24-well micro-titration plates. The results were considered 24 and 72 h post confrontation. The in vivo nematicidal effect was examined using gerbils as a study model. The extracts from the two assessed plants were obtained through maceration using n-hexane as an organic agent. Gerbils artificially infected with H. contortus L3 were treated intraperitoneally with the corresponding extract either individually or in combination. The results showed that the highest individual lethal in vitro effect (96.3%) was obtained with the E-Cham extract at 72 h post confrontation at 40 mg/ml, followed by E-Cato (78.9%) at 20 mg/ml after 72 h. The highest combined effect (98.7%) was obtained after 72 h at 40 mg/ml. The in vivo assay showed that the individual administration of the E-Cato and E-Cham extracts reduced the parasitic burden in gerbils by 27.1% and 45.8%, respectively. Furthermore, the anthelmintic efficacy increased to 57.3% when both extracts were administered in combination. The results of the present study show an important combined nematicidal effect of the two plant extracts assessed against L3 in gerbils.

Diagnosis and genetic analysis of the worldwide distributed Rattus-borne Trypanosoma (Herpetosoma) lewisi and its allied species in blood and fleas of rodents.

Trypanosoma (Herpetosoma) lewisi is a cosmopolitan parasite of rodents strongly linked to the human dispersal of Rattus spp. from Asia to the rest of the world. This species is highly phylogenetically related to trypanosomes from other rodents (T. lewisi-like), and sporadically infects other mammals. T. lewisi may opportunistically infect humans, and has been considered an emergent rat-borne zoonosis associated to poverty. We developed the THeCATL-PCR based on Cathepsin L (CATL) sequences to specifically detect T. (Herpetosoma) spp., and assess their genetic diversity. This method exhibited high sensitivity using blood samples, and is the first molecular method employed to search for T. lewisi in its flea vectors. THeCATL-PCR surveys using simple DNA preparation from blood preserved in ethanol or filter paper detected T. lewisi in Rattus spp. from human dwellings in South America (Brazil and Venezuela), East Africa (Mozambique), and Southeast Asia (Thailand, Cambodia and Lao PDR). In addition, native rodents captured in anthropogenic and nearby human settlements in natural habitats harbored T. (Herpetosoma) spp. PCR-amplified CATL gene fragments (253bp) distinguish T. lewisi and T. lewisi-like from other trypanosomes, and allow for assessment of genetic diversity and relationships among T. (Herpetosoma) spp. Our molecular surveys corroborated worldwide high prevalence of T. lewisi, incriminating Mastomys natalensis as an important carrier of this species in Africa, and supported its spillover from invader Rattus spp. to native rodents in Brazil and Mozambique. THeCATL-PCR provided new insights on the accurate diagnosis and genetic repertoire of T. (Herpetosoma) spp. in rodent and non-rodent hosts, revealing a novel species of this subgenus in an African gerbil. Phylogenetic analysis based on CATL sequences from T. (Herpetosoma) spp. and other trypanosomes (amplified using pan-trypanosome primers) uncovered rodents harboring, beyond mammal trypanosomes of different subgenera, some species that clustered in the lizard-snake clade of trypanosomes.

Survey of intestinal helminths collected from pet rodents in México.

In this survey, intestinal helminths from pet rodents in Mérida, México, were analyzed. A total of 46 mice Mus musculus, 28 hamsters Mesocricetus auratus, 23 rats Rattus norvegicus, and 1 gerbil Meriones unguiculatus were purchased from six pet shops and one black market for wildlife in the city of Mérida. The overall prevalence of helminths in rodents was 61.2% (60/98). Six species of helminths were identified: the zoonotic cestode Rodentolepis nana, and the nematodes Aspiculuris tetraptera, Dentostomella translucida, Syphacia obvelata, Syphacia mesocriceti, and Syphacia muris. Of the 60 infected rodents, 25 (41.7%) harbored 2 or 3 species of helminths. Rodentolepis nana was found in 4.3% of mice and 17.9% of hamsters. This is the first report of infection with S. muris in pet rats. Considering the close physical contact between pet rodents and humans, the presence of R. nana in pets represents a potential risk of transmission, especially to children and immunocompromised individuals.

Larval migration of the ascarid nematode Toxocara canis following infection and re-infection in the gerbil Meriones unguiculatus.

A morphological and immunohistochemical study of larval migration patterns was performed in gerbils that were infected once (primary infected group) or twice (secondary infected group) with 1500 eggs of Toxocara canis. Animals from the primary infected and the re-infected group were killed at different times after infection, and larvae were counted in the intestines, liver, lungs and brain. Fragments of all organs were formalin fixed and paraffin embedded for histology and immunohistochemistry analyses (using polyclonal anti-Toxocara serum raised in rabbits infected with T. canis). In the primary infected group, larvae were more abundant in the intestine at 24 h, in the liver and lungs between 24 and 72 h and in the brain after 96 h; larvae predominated in the brain for up to 60 days after infection. In the re-infected group, an increase in the number of larvae in the liver and a reduction in the number of larvae in the brain was observed up to 60 days after re-infection. Inflammatory reactions were absent or limited. Eosinophils and loose granulomata were observed around the larvae and their antigens in the primary infected group and were more severe. Many eosinophils and typical epithelioid granulomata were observed around larvae in the re-infected group. These results demonstrate that the migration pattern of T. canis larvae in gerbils is similar to that in mice and rats, exhibiting a late neurotropic stage. In the re-infected group, there was histological evidence of an adaptive T-helper 2 (Th-2) response, and larvae were apparently retained within granulomata in the liver, without obvious signs of destruction.

The invasive potential of Giardia intestinalis in an in vivo model.

Giardiasis is a neglected parasitic disease that affects primarily children, in whom it delays physical and mental development. The pathophysiology of giardiasis in not well understood, and most reports have identified Giardia intestinalis trophozoites only in the lumen and on the brush border of the small intestine. We identified Giardia trophozoites within the epithelium of the small intestine of a lactose intolerance patient. The Giardia trophozoites were obtained and cultured in vitro. In addition, we demonstrated Giardia trophozoite invasion in an animal model. Giardia trophozoites invaded the intestinal mucosa and submucosa of infected gerbils. The invasive trophozoites were observed at 21, 30 and 60 days age, and the average numbers of invaded sites were 17 ± 5, 15 ± 4, and 9 ± 3, respectively. We found trophozoites between epithelial cells, at the base of empty goblet cells, in lacteal vessels and within the submucosa. The morphological integrity of the invasive trophozoites was demonstrated via electron microscopy. The analysis of the gerbils infected with the trophozoites of the WB reference strain did not show intraepithelial trophozoites. These results demonstrate another Giardia pathogenic mechanism, opening the door to numerous future studies.

Atividade anti-helmíntica de óleos essenciais de plantas do nordeste brasileiro / Anthelmintic activity of essential oils from plants of Northeast Brazil

O parasitismo por nematoides gastrintestinais representa um dos principais problemas para a produção de ovinos e caprinos. Plantas com atividade anti-helmíntica vêm sendo pesquisadas como uma alternativa de controle destes parasitos. O objetivo deste trabalho foi avaliar a atividade anti-helmíntica de óleos essenciais e decoctos de Lantana camara, Tagetes minuta, Coriandrum sativum, Mentha villosa, Alpinia zerumbet e Cymbopogon citratus. Os óleos foram avaliados in vitro através dos testes de eclosão de ovos (TEO) e de desenvolvimento larvar (TDL) com Haemonchus contortus. Os decoctos foram avaliados in vitro usando o TEO e o teste de desembainhamento artificial larvar sobre H. contortus. O óleo essencial de C. citratus (OECc) na dose de 800 mg/kg foi avaliado in vivo utilizando Meriones unguiculatus (gerbis) infectados experimentalmente com H. contortus. Posteriormente, OECc foi submetido ao processo de nanoencapsulamento utilizando como matriz a quitosana, para a formação de uma nanoemulsão contendo o óleo esssencial de C. citratus nanoencapsulado (OECcN). Posteriormente, foi realizada a avaliação da atividade anti-helmíntica in vivo com ovinos naturalmente infectados com nematoides gastrintestinais utilizando as doses de 500 mg/kg do OECc e 450 mg/kg do OECcN. As concentrações efetivas que inibiram em 50% (CE50) a eclosão das larvas foram de 0,9; 0,6 e 0,5 mg/mL para os decoctos de A. zerumbet, T. minuta e M. villosa. Os decoctos inibiram o desembainhamento larvar de H. contortus na concentração de 310μg/mL para A. zerumbet e M. villosa e na concentração de 620μg/mL para T. minuta e L. camara. As CE50 obtidas no TEO e TDL para os óleos essenciais de A. zerumbet, C. sativum, T. minuta e C. citratus foram de 0,9 e 3,8 mg/mL; 0,6 e 2,8 mg/mL; 0,53 e 1,6 mg/mL; 0,14 e 1,9 mg/mL, respectivamente. OECc teve eficácia de 38,5% na redução da carga parasitária de H. contortus em gerbis. No teste in vivo com ovinos, OECc e OECcN apresentaram eficácia de 48,9 e 69,2% na redução da eliminação de ovos de nematoides gastrintestinais nas fezes de ovinos e eficácia de 52,9% e 71,2% sobre redução da carga de H. contortus, respectivamente. O óleo essencial de C. citratus demonstrou eficácia anti-helmíntica a qual foi aumentada após o nanoencapsulamento, no entanto, não foi obtido o nível terapêutico de anti-helmínticos comerciais.

Gastrointestinal parasites represent one of the main problems for sheep and goat production. Plants with anthelmintic activity are being researched as alternative for the control of these parasites. The objective of this work was to evaluate the anthelmintic activity of essential oils and decoctions of Lantana camara, Tagetes minuta, Coriandrum sativum, Mentha villosa, Alpinia zerumbet and Cymbopogon citratus. The oils were evaluated in vitro through egg hatching test (EHT) and larval development test (LDT) against Haemonchus contortus. The decoctions were evaluated in vitro using EHT and artificial exsheathment larval on H. contortus. The C. citratus essential oil (CcEO) in dose of 800 mg/kg was evaluated in vivo using Meriones unguiculatus (gerbils) experimentally infected with H. contortus. Subsequently, CcEO was subjected to the nanoencapsulation process using chitosan as matrix, for the forming a nanoemulsion containing C. citratus essential oil nanoencapsuled (CcEOn). This was followed by the evaluation of anthelmintic activity in vivo with sheep naturally infected with gastrointestinal nematodes using doses of 500 mg/kg of CcEO and 450 mg/kg of CcEOn. The effective concentrations that inhibited 50% (EC50) larvae hatching were 0.9; 0.6 e 0.5 mg/mL for decoctions A. zerumbet, T. minuta and M. villosa. The decoctions were effective in inhibiting exsheathment H. contortus larvae in the concentration of 310μg/mL for A. zerumbet and M. villosa and the concentration of 620μg/mL for T. minuta and L. camara. The EC50 obtained in EHT and LDT for essential oils of A. zerumbet, C. sativum, T. minuta and C. citratus were 0.9 and 3.8 mg/mL; 0.6 and 2.8 mg/mL; 0.53 and 1.6 mg/mL; 0.14 and 1.9 mg/mL, respectively. OECc had efficacy of 38.5% in reducing the H. contortus parasitic load of gerbils. The in vivo test using sheep, CcEO and CcEOn present efficacy of 48.9 and 69.2% in reduction of the elimination of eggs gastrointestinal nematode in the feces of sheep and effectiveness of 52.9% and 71.2% on reduction of H. contortus burden, respectively. The C. citratus essential oil showed anthelmintic efficacy, which was increased after nanoencapsulation, however it was not yet obtained the therapeutic level of commercial anthelmintics.

Compromised nutrition in gerbils infected by Cystoisospora felis detected through an animal performance analysis tool.

The impact of Cystoisospora felis infection on the nutritional efficiency of gerbils was studied. The variables weight gain and feed intake were measured during four weeks in 28 laboratory gerbils, of which 14 were inoculated with 3.5 × 10(5) sporulated oocysts of C. felis and the remaining 14 were controls. The animals from both groups were weighted, killed, eviscerated and had their carcasses and tissues weighted and compared. A modern tool designed for measuring nutritional performance of farm animals was applied. The results showed compromised nutritional efficiency of the infected animals within the first week after infection. The consequences of these results are discussed here, including the potential impact of infection on farm animals performance.

Compromised nutrition in gerbils infected by Cystoisospora felis detected through an animal performance analysis tool / Comprometimento nutricional em gerbis infectados por Cystoisospora felis detectado através de uma ferramenta de análise de desempenho animal

The impact of Cystoisospora felis infection on the nutritional efficiency of gerbils was studied. The variables weight gain and feed intake were measured during four weeks in 28 laboratory gerbils, of which 14 were inoculated with 3.5 × 10(5) sporulated oocysts of C. felis and the remaining 14 were controls. The animals from both groups were weighted, killed, eviscerated and had their carcasses and tissues weighted and compared. A modern tool designed for measuring nutritional performance of farm animals was applied. The results showed compromised nutritional efficiency of the infected animals within the first week after infection. The consequences of these results are discussed here, including the potential impact of infection on farm animals performance.(AU)

O impacto da infecção por Cystoisospora felis na eficiência nutricional de gerbis foi estudado. As variáveis ganho de peso e consumo de ração foram mensuradas durante quatro semanas em 28 gerbis de laboratório, dos quais 14 foram inoculados com 3,5 × 10(5) oocistos esporulados de C. felis e os 14 restantes serviram como controle. Os animais de ambos os grupos foram pesados, mortos, eviscerados e tiveram suas carcaças e tecidos pesados e comparados. Uma ferramenta moderna desenvolvida para mensurar o desempenho nutricional de animais de produção foi aplicada. Os resultados mostraram eficiência nutricional comprometida dos animais infectados na primeira semana após a infecção. As consequências destes resultados são discutidas aqui, incluindo o possível impacto de infecção no desempenho de animais de produção.(AU)

Compromised nutrition in gerbils infected by Cystoisospora felis detected through an animal performance analysis tool / Comprometimento nutricional em gerbis infectados por Cystoisospora felis detectado através de uma ferramenta de análise de desempenho animal

The impact of Cystoisospora felis infection on the nutritional efficiency of gerbils was studied. The variables weight gain and feed intake were measured during four weeks in 28 laboratory gerbils, of which 14 were inoculated with 3.5 × 10(5) sporulated oocysts of C. felis and the remaining 14 were controls. The animals from both groups were weighted, killed, eviscerated and had their carcasses and tissues weighted and compared. A modern tool designed for measuring nutritional performance of farm animals was applied. The results showed compromised nutritional efficiency of the infected animals within the first week after infection. The consequences of these results are discussed here, including the potential impact of infection on farm animals performance.

O impacto da infecção por Cystoisospora felis na eficiência nutricional de gerbis foi estudado. As variáveis ganho de peso e consumo de ração foram mensuradas durante quatro semanas em 28 gerbis de laboratório, dos quais 14 foram inoculados com 3,5 × 10(5) oocistos esporulados de C. felis e os 14 restantes serviram como controle. Os animais de ambos os grupos foram pesados, mortos, eviscerados e tiveram suas carcaças e tecidos pesados e comparados. Uma ferramenta moderna desenvolvida para mensurar o desempenho nutricional de animais de produção foi aplicada. Os resultados mostraram eficiência nutricional comprometida dos animais infectados na primeira semana após a infecção. As consequências destes resultados são discutidas aqui, incluindo o possível impacto de infecção no desempenho de animais de produção.

Effects of albendazole on Litomosoides chagasfilhoi (Nematoda: Filarioidea) females in vivo.

Gerbils (Meriones unguiculatus) experimentally infected with Litomosoides chagasfilhoi were treated with a single oral dose of 40 or 80 mg of albendazole, respectively. Observation of the microfilaremia after the treatment showed that both single oral doses of albendazole decreased the microfilaremia in L. chagasfilhoi infection. The body wall was composed of a cuticle, a hypodermis, and a muscular layer, and treated nematodes showed no morphological alterations. The ultrastructural alterations produced by treatment with 40 mg of albendazole included a higher number of membrane invaginations in the basal labyrinth of the uterine epithelium and the presence of myelin figures in this region. Inside the uterus, most embryos and microfilariae were disintegrated. The treatment with 80 mg of albendazole did not produce alterations in the uterine wall, and the number of vesicles near the microfilariae sheath was smaller than that observed in the untreated and in the 40-mg treatment groups. However, all the microfilariae observed in the uterus were extensively damaged with cytoplasmic vacuolization and cellular degeneration. No alterations in the intestinal cells were observed after treatment with 40 or 80 mg of albendazole. The present study contributes to the knowledge of albendazole's effects in filariids and demonstrates the potential embryotoxic and microfilaricidal consequences of this drug.

Experimental infection and adaptation of Rodentolepis nana to the Mongolian jird Meriones unguiculatus.

A mouse-derived strain of Rodentolepis ( = Hymenolepis) nana was transferred to the Mongolian jird Meriones unguiculatus. It was found that M. unguiculatus has low susceptibility to R. nana mouse isolates. Likewise, adaptation of the parasite to jird hosts, in the absence of dexamethasone treatment, was not demonstrable, at least during ten-passage trials. Nevertheless, the parasite was able to establish, grow and develop to gravid adults in M. unguiculatus treated daily with dexamethasone. Prepatent periods in dexamethasone-treated jirds in ten-passage series ranged from 10 to 17 days post-infection (DPI), the average being 12 days, and the patent periods lasted from 18 to 30 DPI, with an average of 25 days. The population pattern of faecal egg output in immunosuppressed jirds suggests that under a daily dexamethasone treatment protocol, the parasite is able to maintain egg production as long as treatment is sustained.

Hypnozoites of Cystoisospora Frankel, 1977 (Apicomplexa: Cystoisosporinae) in Mongolian gerbil lymph nodes and their transmission to cats free of coccidia.

Nine Mongolian gerbils (Meriones unguiculatus) were fed with 5.6 x 10(5) Cystoisospora sporulated oocysts orally. After 28 days post inoculation (DPI) four animals were euthanized, and their mesenteric lymph nodes were removed and they were submitted to peptic digestion technique and samples of them were submitted to transmission electron microscopy for hypnozoites identification. From lymph nodes digestion 4 x 10(2) hypnozoites/mL were obtained. Morphologically they were banana or stick form in shape, and measured 18.17 (15.09-20.02) in length by 6.21 (5.48-7.06) microm in width. In the same experiment, at 6 DAI, five gerbils were posted and liver, mesenteric lymph nodes and spleen were removed from each animal and were homogenized before given to three cats free of coccidia. All visceras used individually in each cat were capable to induce infection of species, C. felis and C. rivolta.

Loss of infectivity of Neospora caninum oocysts maintained for a prolonged time.

The purpose of this study was to investigate whether sporulated Neospora caninum oocysts, which had been stored for 46 mo in a 2% sulfuric acid solution at 4 degrees C, remain morphologically viable and infective to gerbils (Meriones unguiculatus). Six gerbils were orally inoculated with doses of 400 or 1,200 oocysts. Two mo after inoculation, the animals did not show any clinical signs, had no histological lesions, and were seronegative for N. caninum at 1: 50 in an immunofluorescent antibody test. PCR using the brain from each gerbil did not reveal N. caninum specific DNA. We conclude that oocysts preserved for 46 mo are not infective, despite being morphologically intact.

[Experimental infection of the gerbil (Meriones unguiculatus) by Colombian isolates of Giardia duodenalis]. / Comportamiento de la infección experimental por aislamientos colombianos de Giardia duodenalis en el modelo animal del gerbo (Meriones unguiculatus).

INTRODUCTION: Natural and experimental Giardia infections have been reported from bovines, equines, goats, canines, felines and rodents such as mice, rats and gerbils. The latter have provided successful animal models for Giardia duodenalis and Giardia muris experimental infections. OBJECTIVE: The gerbil model was used to establish the pattern of infection of Colombian Giardia human isolates. MATERIALS AND METHODS: Giardia cysts were obtained from stool specimens of symptomatic giardiasis patients by means of sucrose-percoll gradients. Animal inoculation was performed by gastric intubation and injection with 5 x 10(3) Giardia cysts. The course of infection was established by counting cysts every day and trophozoites weekly throughout a period of 30 days. RESULTS: The pattern of cyst excretion was found to be intermittent. Cysts were released during the second and third weeks of infection but not during the first or fourth weeks. The mean minimal number of cysts released per 2-hr collection period was 79 and the mean maximum number was 17,943. Colonization of the small intestine by trophozoites was observed with a mean number ranging from 15,000 to 6,577,778 trophozoites/ml. DISCUSSION AND CONCLUSIONS: Gerbils inoculated with G. duodenalis isolates obtained from geographical areas outside Colombia resolved the infection between 86 and 114 days after infection, whereas gerbils infected with Colombian G. duodenalis isolates resolved the infection at 30 days. The gerbil proved to be a good animal model for experimental infection with Colombian isolates of G. duodenalis. Experimental Giardia infection of gerbils permit a sufficient yield of cysts and trophozoites to be used as antigens for the immunization of other animals and to obtain Giardia antibodies that could be used for Giardia antigen detection assays in stool specimens.