Central nervous system alterations was described in Chagas disease in both human and experimental models, leading to meningoencephalitis, stroke and cognitive impairment. Recently, our group ...demonstrated that acute infection by Trypanossoma cruzi leads to cerebral microvasculophaty in mice with endothelial dysfunction, capillary rarefaction, increased rolling and leukocyte adhesion. Only benznidazole and nifurtimox are available for clinical treatment, they have an efficiency of 80% in the acute phase and less than 20% in chronic phase. However, the effect of these drugs on brain microcirculation has not yet been evaluated. We hypothesized that early treatment with benznidazole could protect brain microcirculation during acute experimental Chagas disease. Swiss Webster mice were inoculated with 10
trypomastigotes forms of T. cruzi, and after 24 h they were treated with 50 or 100 mg/kg/day of benznidazole for 14 consecutive days. In untreated infected mice, we observed cerebral microvascular rarefaction, increase in leukocyte rolling and adhesion, reduced cerebral blood flow, and increased CD3+ and F4-80+ cells in brain tissue. Early treatment with benznidazole at 100 mg/kg/day and 50 mg/kg/day prevented the occurrence of the alterations mentioned. Here, we show that BZ is able to protect the microcirculation and reduced brain inflammation in acute experimental Chagas disease.
The highly virulent
RH strain is maintained through successive passages in mice, but there is still a lack of studies that refine these procedures from a 3Rs perspective, where humanitarian ideals ...aim to minimize the stress, pain, or suffering of the animals used in the research without the loss of results. The aim of this study was to establish humane endpoints in Swiss Webster mice inoculated with the
RH strain. A total of 52 mice were infected with 5 × 10
tachyzoites/mL and monitored for periods of up to 5 days. The parameters body weight; hair condition; higher than normal body temperature; hypothermia; respiratory function; pain; soft stools or diarrhea; bloody diarrhea; tense, nervous, or in distress during handling; and ascites were recorded daily in score tables. The results showed that prominent piloerection, respiratory function, pain parameters, and ascites are important clinical signs to be used as a cut-off point for implementing euthanasia. The application of this refinement method helped to avoid animal suffering and pain without compromising the number of parasites recovered. We therefore suggest adopting these parameters in research protocols that require the maintenance of the
RH strain in murine models to avoid and reduce animal suffering.
Housing Density and Aggression in Syrian Hamsters Elidio, Hyago da Silva Medeiros; Coelho, Jhônata Willy Rocha; Silva, Luiz Cesar Cavalcanti Pereira da ...
Journal of the American Association for Laboratory Animal Science,
09/2021, Letnik:
60, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The Syrian hamster (Mesocricetus auratus) is a solitary and naturally territorial animal, with female hamsters being moreaggressive than males. This behavior makes handling difficult because they are ...usually housed in groups, which can leadto aggressive behavior. The objective of this study was to refine the management of Syrian hamsters in order to minimizeaggressiveness, reduce the animal injuries, and lessen the risk of accidents among laboratory animal technicians due to the hamster aggression during handling. The experiment was conducted at the Center for Animals Experimentation, OswaldoCruz Institute. Four groups of hamsters were observed by video recording: group 1 (group-housed males, 6 to 8 wk of age),group 2 (group-housed females 6 to 8 wk of age), group 3 (group-housed female, 3 to 4 wk of age), and group 4 (individually housed females, 6 to 8 wk of age). Group 1 animals were less aggressive and agitated both during housing and during handling by the animal technician as compared with groups 2 and 3. Groups 2 and 3 showed greater agitation and aggression. Marked reduction in the level of aggressiveness and agitation was observed in group 4 as compared with all other groups evaluated during handling by the animal technician. Male hamsters housed in groups of 4 and females housed individually has reduced risks of accident during handling, thereby averting distress and consequent physiologic alterations. Avoiding these risks is essential to obtaining reliable experimental results.
Sporotrichosis is a subcutaneous infection caused by fungi from the genus Sporothrix. It is transmitted by inoculation of infective particles found in plant-contaminated material or diseased animals, ...characterizing the classic sapronotic and emerging zoonotic transmission, respectively. Since 1998, southeastern Brazil has experienced a zoonotic sporotrichosis epidemic caused by S. brasiliensis, centred in the state of Rio de Janeiro. Our observation of feline sporotrichosis cases in Brasília (Midwestern Brazil), around 900 km away from Rio de Janeiro, led us to question whether the epidemic caused by S. brasiliensis has spread from the epicentre in Rio de Janeiro, emerged independently in the two locations, or if the disease has been present and unrecognized in Midwestern Brazil. A retrospective analysis of 91 human and 4 animal cases from Brasília, ranging from 1993 to 2018, suggests the occurrence of both sapronotic and zoonotic transmission. Molecular typing of the calmodulin locus identified S. schenckii as the agent in two animals and all seven human patients from which we were able to recover clinical isolates. In two other animals, the disease was caused by S. brasiliensis. Whole-genome sequence typing of seven Sporothrix spp. strains from Brasília and Rio de Janeiro suggests that S. brasiliensis isolates from Brasília are genetically distinct from those obtained at the epicentre of the outbreak in Rio de Janeiro, both in phylogenomic and population genomic analyses. The two S. brasiliensis populations seem to have separated between 2.2 and 3.1 million years ago, indicating independent outbreaks or that the zoonotic S. brasiliensis outbreak might have started earlier and be more widespread in South America than previously recognized.
Background
The in situ detection of parasite antigens in tissue sections by immunohistochemistry (IHC) is a diagnostic alternative for human American tegumentary leishmaniasis (ATL), but has not been ...used for the diagnosis of cutaneous lesions in dogs with ATL. This study describes the results of IHC for the detection of amastigote forms and other Leishmania sp. antigen-positive cells and compares the results of IHC, histopathology and cytopathology for the diagnosis of canine ATL. In addition, possible cross-reactivity with sporotrichosis is analyzed.
Methods
Forty paraffin-embedded biopsies and 40 smears of cutaneous lesions from dogs with ATL, confirmed by isolation and characterization of Leishmania (Viannia) braziliensis, and 40 paraffin-embedded biopsies of cutaneous lesions from dogs with sporotrichosis, confirmed by isolation of Sporothrix schenckii in culture (control group), were studied.
Results
Immunohistochemistry was more sensitive in detecting amastigote forms than cytopathology and histopathology, with a positivity rate of 70% (n=28) versus 37.5% and 22.5% for histopathology and cytopathology, respectively. Cytoplasmic staining of mononuclear and endothelial cells was detected by IHC, which was highly specific since no cytoplasmic staining of these cells or staining of fungal structures was observed in sporotrichosis fragments.
Conclusions
In view of the higher sensitivity of IHC in detecting Leishmania sp. antigen and patterns of positivity for Leishmania sp. antigen compared to histopathology or cytopathology and the absence of cross-reactions with sporotrichosis, we recommend this technique for the diagnosis of canine tegumentary leishmaniasis.
A leishmaniose é uma doença infecto-parasitária que acomete seres humanos e animais, causada por protozoários do gênero Leishmania. As leishmanioses são importante problema de saúde pública em vários ...países e estão incluídas entre as seis endemias de maior relevância mundial. São classificadas em tegumentar (LT) cutânea e mucocutânea - e visceral (LV). A transmissão ocorre através de picada de insetos flebotomíneos pertencentes aos gêneros Lutzomyia (Novo Mundo) e Phlebotomus(Velho Mundo). A Leishmaniose Tegumentar Americana (LTA) é uma zoonose distribuída no território brasileiro. Possui evolução crônica e acomete a pele e mucosas, isoladamente ou em associação, de seres humanos, cães, gatos e eqüinos. Nos cães, se caracteriza pela presença de lesões cutâneas ulceradas, recobertas por crostas, localizadas nas orelhas, bolsa escrotal, focinho e membros. A Leishmaniose visceral é uma zoonose que ocorre nas regiões subtropicais e tropicais, causada pela Leishmania (Leishmania) chagasi, no Novo e no Velho Mundo. No Brasil, a Leishmaniose Visceral Canina (LVC) coexiste com a doença humana e os cães são seu reservatório doméstico. A eutanásia do cão é criticada por isso enfrenta limitações. Apesar das ações de vigilância e controle de LV adotadas no DF, a doença permanece em áreas urbanas e rurais.
Housing Density and Aggression in Syrian Hamsters Elidio, Hyago da Silva Medeiros; Coelho, Jhônata Willy Rocha; da Silva, Luiz Cesar Cavalcanti Pereira ...
Journal of the American Association for Laboratory Animal Science,
09/2021, Letnik:
60, Številka:
5
Journal Article
Recenzirano
The Syrian hamster (Mesocricetus auratus) is a solitary and naturally territorial animal, with female hamsters being more aggressive than males. This behavior makes handling difficult because they ...are usually housed in groups, which can lead to aggressive behavior. The objective
of this study was to refine the management of Syrian hamsters in order to minimize aggressiveness, reduce the animal injuries, and lessen the risk of accidents among laboratory animal technicians due to the hamster aggression during handling. The experiment was conducted at the Center for
Animals Experimentation, Oswaldo Cruz Institute. Four groups of hamsters were observed by video recording: group 1 (group-housed males, 6 to 8 wk of age), group 2 (group-housed females 6 to 8 wk of age), group 3 (group-housed female, 3 to 4 wk of age), and group 4 (individually housed females,
6 to 8 wk of age). Group 1 animals were less aggressive and agitated both during housing and during handling by the animal technician as compared with groups 2 and 3. Groups 2 and 3 showed greater agitation and aggression. Marked reduction in the level of aggressiveness and agitation was observed
in group 4 as compared with all other groups evaluated during handling by the animal technician. Male hamsters housed in groups of 4 and females housed individually have reduced risks of accident during handling, thereby averting distress and consequent physiologic alterations. Avoiding these
risks is essential to obtaining reliable experimental results.
Toxoplasmosis is a globally distributed zoonosis caused by Toxoplasma gondii. This protozoan is capable of infecting mammals and birds and can cause significant impacts on human and animal health. ...Much of what is known about the parasite’s biology, the immune mechanisms involved in toxoplasmosis, and the development of diagnostic tests for this protozoan disease is due to the maintenance of the parasite in laboratory mice. However, the increasing debate on the use of biomodels in scientific research has brought about the need to implement the principles of the 3Rs in laboratory protocols, such as experimental infections with T. gondii in murine models. Therefore, this study aimed to establish the humane endpoints for experimental infection with the T. gondii RH strain in Swiss Webster mice. The results presented here seek to disseminate the method we have proposed for the humane finalization of these animals in experimental protocols using this highly virulent strain as a method of refinement that seeks to enhance animal welfare. The highly virulent Toxoplasma gondii RH strain is maintained through successive passages in mice, but there is still a lack of studies that refine these procedures from a 3Rs perspective, where humanitarian ideals aim to minimize the stress, pain, or suffering of the animals used in the research without the loss of results. The aim of this study was to establish humane endpoints in Swiss Webster mice inoculated with the T. gondii RH strain. A total of 52 mice were infected with 5 × 10sup.6 tachyzoites/mL and monitored for periods of up to 5 days. The parameters body weight; hair condition; higher than normal body temperature; hypothermia; respiratory function; pain; soft stools or diarrhea; bloody diarrhea; tense, nervous, or in distress during handling; and ascites were recorded daily in score tables. The results showed that prominent piloerection, respiratory function, pain parameters, and ascites are important clinical signs to be used as a cut-off point for implementing euthanasia. The application of this refinement method helped to avoid animal suffering and pain without compromising the number of parasites recovered. We therefore suggest adopting these parameters in research protocols that require the maintenance of the T. gondii RH strain in murine models to avoid and reduce animal suffering.
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