RESUMO
Leptospirosis is a zoonosis that humans can contract via contact with animal reservoirs directly or with water contaminated with their urine. The primary reservoir of pathogenic leptospires within urban slum environments is the Norway rat (Rattus norvegicus). Motivated by the annual outbreaks of human leptospirosis in slum urban settings, the within population infection dynamics of the Norway rat were investigated in Pau da Lima, an community in Salvador, Brazil. A mechanistic model of the dynamics of leptospire infection was informed by extensive field and laboratory data was developed and explored analytically. To identify the intraspecific transmission route of most importance, a global sensitivity analysis of the basic reproduction number to its components was performed. In addition, different methods of rodent control were investigated by calculating target reproduction numbers. Our results suggest environmental transmission plays an important role in the maintenance of infection in the rodent population. To control numbers of wild Norway rats, combinations of controls are recommended but environmental control should also be investigated to reduce prevalence of infection in rats.
Assuntos
Reservatórios de Doenças/microbiologia , Leptospirose/epidemiologia , Leptospirose/prevenção & controle , Áreas de Pobreza , Ratos , Doenças dos Roedores/epidemiologia , Doenças dos Roedores/prevenção & controle , Animais , Brasil/epidemiologia , Reservatórios de Doenças/veterinária , Feminino , Leptospirose/veterinária , Masculino , Dinâmica Populacional , PrevalênciaRESUMO
Corynebacterium bovis causes an opportunistic infection of nude (Foxn1, nu/nu) mice, leading to nude mouse hyperkeratotic dermatitis (scaly skin disease). Enzootic in many nude mouse colonies, C. bovis spreads rapidly to naive nude mice, despite modern husbandry practices, and is very difficult to eradicate. To facilitate rapid detection in support of eradication efforts, we investigated a surveillance method based on quantitative real-time PCR (qPCR) evaluation of swabs collected from the horizontal exhaust manifold (HEM) of an IVC rack system. We first evaluated the efficacy of rack sanitation methods for removing C. bovis DNA from the HEM of racks housing endemic colonies of infected nude mice. Pressurized water used to flush the racks' air exhaust system followed by a standard rack-washer cycle was ineffective in eliminating C. bovis DNA. Only after autoclaving did all sanitized racks test negative for C. bovis DNA. We then measured the effects of stage of infection (early or established), cage density, and cage location on the rack on time-to-detection at the HEM. Stage of infection significantly affected time-to-detection, independent of cage location. Early infections required 7.3 ± 1.2 d whereas established infections required 1 ± 0 d for detection of C. bovis at the HEM. Cage density influenced the quantity of C. bovis DNA detected but not time-to-detection. The location of the cage on the rack affected the time-to-detection only during early C. bovis infections. We suggest that qPCR swabs of HEM are useful during the routine surveillance of nude mouse colonies for C. bovis infection.
Assuntos
Microbiologia do Ar/normas , Poluição do Ar em Ambientes Fechados/análise , Infecções por Corynebacterium/microbiologia , Corynebacterium/isolamento & purificação , Abrigo para Animais/normas , Doenças dos Roedores/microbiologia , Ventilação/normas , Criação de Animais Domésticos/métodos , Animais , Infecções por Corynebacterium/prevenção & controle , DNA Bacteriano/isolamento & purificação , Dermatite/microbiologia , Feminino , Ciência dos Animais de Laboratório , Camundongos , Camundongos Nus , Reação em Cadeia da Polimerase em Tempo Real , Doenças dos Roedores/prevenção & controle , Saneamento , EsterilizaçãoRESUMO
Handling a rodent disease outbreak in a facility can be a challenge. After the University of Colorado Denver Office of Laboratory Animal Resources enhanced its sentinel monitoring program, > 90% of the animal colonies housed in a vivarium at the Anschutz Medical Campus (with an area of 50,000 net ft(2)), serving the labs of > 250 principal investigators, tested positive for multiple infective agents including mouse parvovirus, fur mites, pinworms and epizootic diarrhea of infant mice. The authors detail the process by which they planned and executed a shutdown and a decontamination of the facility, which involved the rederivation or cryopreservation of > 400 unique genetically modified mouse lines. The authors discuss the aspects of the project that were successful as well as those that could have been improved.
Assuntos
Animais de Laboratório , Descontaminação/métodos , Abrigo para Animais/normas , Controle de Infecções/métodos , Infecções/veterinária , Doenças dos Roedores/prevenção & controle , Vigilância de Evento Sentinela/veterinária , Animais , Criopreservação/métodos , Infecções/transmissão , Camundongos , Doenças dos Roedores/transmissãoRESUMO
Bovine herpesvirus-1 (BoHV-1) infection is distributed worldwide and the development of new tools to fight against this pathogen has become extremely important. In this work a recombinant modified vaccinia virus Ankara (MVA) vector expressing the secreted version of glycoprotein D, MVA-gDs, was obtained and evaluated as a candidate vaccine. First, the correct expression, antigenicity, and N-glycosylation of glycoprotein D were confirmed by molecular techniques. Then MVA-gDs was used as parenteral immunogen in BALB/C mice in which a specific anti-gD humoral immune response was induced and maintained for 7 mo. Two doses of MVA-gDs supplemented with cholera toxin delivered by intranasal immunization induced IgA anti-gD humoral immune responses in nasal and bronchopulmonary washes, as well as IgG anti-gD antibodies in serum samples. In order to evaluate the protection conferred by MVA-gDs immunization, a rabbit BoHV-1 challenge assay was performed. A shorter viral excretion period and a reduction in the number of animals shedding BoHV-1 was observed in the group immunized with recombinant MVA-gDs. In conclusion our data encourage further studies to evaluate MVA-gDs, alone or combined with other immunogens, as a candidate vaccine for BoHV-1.
Assuntos
Portadores de Fármacos , Vacinas contra Herpesvirus/imunologia , Vaccinia virus/genética , Proteínas Virais/imunologia , Adjuvantes Imunológicos/administração & dosagem , Adjuvantes Imunológicos/genética , Administração Intranasal , Animais , Anticorpos Antivirais/análise , Anticorpos Antivirais/sangue , Líquido da Lavagem Broncoalveolar/imunologia , Toxina da Cólera/administração & dosagem , Toxina da Cólera/genética , Modelos Animais de Doenças , Feminino , Vetores Genéticos , Infecções por Herpesviridae/imunologia , Infecções por Herpesviridae/prevenção & controle , Vacinas contra Herpesvirus/administração & dosagem , Vacinas contra Herpesvirus/genética , Imunoglobulina A/análise , Imunoglobulina G/sangue , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Mucosa Nasal/imunologia , Doenças dos Roedores/imunologia , Doenças dos Roedores/prevenção & controle , Fatores de Tempo , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Proteínas Virais/genética , Eliminação de Partículas ViraisRESUMO
The effect of Lactobacillus casei CRL 431 (Lc), when administered as a supplement to a repletion diet, on the resistance of malnourished mice to Candida albicans infection was studied. Weaned mice were malnourished by being given a protein-free diet (PFD) for 21 days. The malnourished mice were then fed a balanced conventional diet (BCD) for 7 days or BCD for 7 days with supplemental Lc on days 6 and 7 (BCD+Lc). Malnourished (MNC) and well-nourished (WNC) mice were used as controls. At the end of the treatments the mice were infected intraperitoneally with C. albicans. Animals that had received probiotics had improved survival and resistance against this infection compared to those in the BCD and MNC groups. The number and fungicidal activity of phagocytes, and the concentrations of tumor necrosis factor-α, interferon-γ and interleukin-6 (IL-6), increased in blood and infected tissues in all experimental groups, but MNC mice showed lower concentrations than those in the WNC group. BCD and BCD+Lc mice showed higher concentrations of these variables than those in the MNC group, but only the BCD+Lc group presented values similar to the WNC mice. Malnutrition also impaired the production of IL-17 and IL-10 in response to infection. Both repletion treatments normalized IL-17 concentrations, but IL-10 in the BCD+Lc group was significantly higher than in WNC mice. The addition of L. casei to the repletion diet normalized the immune response against C. albicans, allowing efficient recruitment and activation of phagocytes, as well as effective release of pro-inflammatory cytokines. In addition, probiotic treatment induced an increase in IL-10 concentrations, which would have helped to prevent damage caused by the inflammatory response.
Assuntos
Antibiose , Candida albicans/crescimento & desenvolvimento , Candidíase/prevenção & controle , Lacticaseibacillus casei/fisiologia , Desnutrição/complicações , Probióticos , Animais , Citocinas/sangue , Dieta/métodos , Modelos Animais de Doenças , Masculino , Camundongos , Fagócitos/imunologia , Doenças dos Roedores/prevenção & controle , Análise de SobrevidaRESUMO
Mutations of influenza virus increase concerns of worldwide epidemics resulting from the newly emergent strains. Current influenza vaccines are inefficient and require annual vaccinations. W805EC adjuvant is an oil-in-water emulsion composed of nanodroplets with an average diameter of approximately 400 nm. The nanoemulsion adjuvant has been used successfully to stimulate the immune response when mixed with several other antigens in animal models. In this study, W805EC nanoemulsion adjuvant activity was evaluated using nasal influenza vaccination in a murine model. Five to twenty percent W805EC adjuvant was used to inactivate influenza A/Puerto Rico/8/34/05 (H1N1). Mice immunized with the nanoemulsion adjuvanted influenza virus intranasally showed a robust specific humoral immune response as demonstrated using ELISA and HAI assays. Serum HAI titers were more than 104 following two vaccinations. Vaccinated mice were also protected against challenge with an LD80 of live influenza virus. Splenocytes from vaccinated mice were assayed for cytokine production following virus stimulation. The cytokine profile demonstrated a robust cellular immune response with enhanced Th1 and Th17 immunity that provided balanced immunity against both intracellular and extracellular forms of the virus. Additionally, the vaccine preparations showed minimal protein degradation but remained potent when stored at 4°C for up to three months. This work demonstrates that W805EC nanoemulsion adjuvant can effectively enhance the immunogenicity of influenza hemagglutinin antigen. The nanoemulsion adjuvant can result in antigen sparing and cross-protection. The potential exists for a nasally administered influenza vaccine that may require little or no refrigerated storage.
Assuntos
Adjuvantes Imunológicos/administração & dosagem , Emulsões/administração & dosagem , Vacinas contra Influenza/efeitos adversos , Vacinas contra Influenza/imunologia , Adjuvantes Imunológicos/efeitos adversos , Administração Intranasal , Animais , Anticorpos Antivirais/sangue , Citocinas/metabolismo , Emulsões/efeitos adversos , Ensaio de Imunoadsorção Enzimática , Feminino , Testes de Inibição da Hemaglutinação , Vírus da Influenza A Subtipo H1N1/imunologia , Vacinas contra Influenza/administração & dosagem , Leucócitos Mononucleares/imunologia , Masculino , Camundongos , Infecções por Orthomyxoviridae/mortalidade , Infecções por Orthomyxoviridae/prevenção & controle , Porto Rico , Doenças dos Roedores/mortalidade , Doenças dos Roedores/prevenção & controle , Baço/imunologia , Análise de Sobrevida , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/efeitos adversos , Vacinas de Produtos Inativados/imunologiaRESUMO
Rodents are responsible for the transmission of more than 60 diseases both to human beings and to domestic animals. The increase in rodent infestation in a given area brings several health problems to the nearby population. Thus, when infestation increases, it is time to take intervention measures. Although many countries have implemented programs aimed at controlling rodent infestation, literature on studies evaluating the effectiveness of intervention measures in urban areas is scarce. Aimed at contributing to the understanding of rodents' population dynamics in urban areas, the objective of this study was to evaluate the effectiveness of the control methods proposed by "Programa de Vigilancia e Controle de Roedores do Municipio de Sao Paulo" (Program for Rodents Surveillance and Control in Sao Paulo Municipality), conducted on Jardim Comercial District. As a first step, a survey to assess infestation rates was conducted in 1529 dwellings located in the area studied. After that, a chemical control upon rodents was accomplished in every dwelling infested. One week and six months after completion of control measures, a new evaluation on infestation rates was carried out, in order to verify the effectiveness of the procedures taken and to estimate the re-infestation capacity. Initial infestation rate was 40.0%, and the final infestation rate, 14.4%. Therefore, the effectiveness of the control methods utilized was 63.8%. It can thus be concluded that the control methods applied were quite effective.
Assuntos
Transmissão de Doença Infecciosa/prevenção & controle , Controle de Roedores/métodos , Doenças dos Roedores/prevenção & controle , Animais , Brasil/epidemiologia , Coleta de Dados , Humanos , Saúde Pública , Ratos , Doenças dos Roedores/epidemiologia , Saúde da População UrbanaRESUMO
The ventilation method used in the management of laboratory rats is important in maintaining their health. Rats kept under general diluting ventilation (GDV) are exposed to high levels of pollutants present in the environment (dust, airborne bacteria, etc.) or those pollutants produced by animal metabolism and excretion inside the boxes (e.g. ammonia and carbon dioxide). These pollutants may contribute to respiratory pathologies. An alternative experimental ventilation system for laboratory animal housing using intracage ventilation technology (individually ventilated cage system, IVC) was developed. In this system, ammonia levels decreased and rats exhibited better reproductive performance and a lower incidence of pneumonia than rats maintained under GDV. Using two different levels of air speed (0.03-0.26 m/s: IVC(1); 0.27-0.80 m/s: IVC(2)), the effects of IVC were compared with GDV (control) in Wistar rats in terms of respiratory mucus properties, on the nasal epithelium (as measured by quantitative morphometry) and on the lungs (as determined by the cellular composition obtained by bronchoalveolar lavage). Mucus of the respiratory system was evaluated using the following techniques: rheology (viscoelasticity) by microrheometer, in vitro mucociliary transportability (frog palate) and contact angle (an indicator of adhesivity). Also, membrane transepithelial potential difference was measured as a biomarker of airway integrity. After bedding was changed, ammonia concentrations inside the cages on day 3 were significantly higher for GDV than for IVC(1) and IVC(2). The potential-difference values for IVC(1), IVC(2) and GDV in the epiglottis and in the trachea also showed differences. Although some significant differences were observed across the three groups in counts of some cell types, the intragroup results were highly variable among individuals and inconsistent between sexes. No significant differences in the other parameters were found across groups. These results establish that rats maintained under GDV in relatively unregulated conditions are exposed to factors that can lead to deleterious effects on the ciliated epithelium of the airways, and that these effects can be prevented by the use of IVC.
Assuntos
Bem-Estar do Animal , Abrigo para Animais , Doenças Respiratórias/prevenção & controle , Doenças dos Roedores/prevenção & controle , Ventilação/métodos , Pressão do Ar , Amônia , Criação de Animais Domésticos/instrumentação , Animais , Animais de Laboratório , Brasil , Líquido da Lavagem Broncoalveolar/citologia , Epitélio/metabolismo , Epitélio/patologia , Humanos , Inflamação/prevenção & controle , Masculino , Nariz/patologia , Ratos , Ratos WistarAssuntos
Humanos , Camundongos , Orthohantavírus , Infecções por Hantavirus/epidemiologia , Infecções por Hantavirus/história , Infecções por Hantavirus/prevenção & controle , Infecções por Hantavirus/transmissão , Chile , Controle de Roedores , Doenças dos Roedores/prevenção & controle , Doenças dos Roedores/transmissão , Pessoal de Saúde , Síndrome Pulmonar por Hantavirus/prevenção & controle , Síndrome Pulmonar por Hantavirus/transmissãoRESUMO
We present a comparison of methods for evaluating the potency of foot and mouth disease vaccine in the laboratory. The anti-FMDV antibodies (Ab) in vaccinated mice were tested by liquid phase (lp) ELISA, solid phase (sp) ELISA and virus neutralization (VN), and were compared with the Ab titres detected by lpELISA, which is the official test in Argentina for testing the potency of FMD vaccines and protection against a virulent challenge in cattle. The results demonstrated that it is possible to relate the Ab levels induced in vaccinated mice with both the Ab and protective responses elicited in cattle. Furthermore, it was found that the anti-FMDV Ab titres in mice detected by lpELISA 14 days after vaccination should be an accurate parameter for predicting the results of the challenge test in cattle. Thus, this test in mice appears to be an inexpensive and rapid alternative for testing FMD vaccines in cattle.
Assuntos
Anticorpos Antivirais/análise , Doenças dos Bovinos/prevenção & controle , Febre Aftosa/prevenção & controle , Doenças dos Roedores/prevenção & controle , Vacinação/veterinária , Animais , Bovinos , Doenças dos Bovinos/imunologia , Ensaio de Imunoadsorção Enzimática/veterinária , Febre Aftosa/imunologia , Camundongos , Testes de Neutralização/veterinária , Doenças dos Roedores/imunologiaRESUMO
Administration to rodents (Syrian hamsters, mice, guinea pigs, rabbits) of minimal doses of attenuated strain 15 VEE (up to 20 ImD50) provided protection against respiratory challenge with a highly virulent strain of Venezuelan equine encephalomyelitis virus. The protection is observed in a wide range of doses (up to LD50 hundreds and even thousands).
Assuntos
Vírus da Encefalite Equina Venezuelana/imunologia , Encefalomielite Equina Venezuelana/prevenção & controle , Infecções Respiratórias/prevenção & controle , Doenças dos Roedores/prevenção & controle , Vacinas Virais/imunologia , Animais , Cricetinae , Avaliação Pré-Clínica de Medicamentos , Vírus da Encefalite Equina Venezuelana/patogenicidade , Encefalomielite Equina Venezuelana/etiologia , Cobaias , Imunização , Mesocricetus , Camundongos , Coelhos , Infecções Respiratórias/etiologia , Doenças dos Roedores/etiologia , Inoculações Seriadas , Vacinas Atenuadas/administração & dosagem , Vacinas Atenuadas/imunologia , Vacinas Virais/administração & dosagem , VirulênciaRESUMO
Guinea pigs are natural reservoirs of Chagas' disease. Domestic breeding and local trade of these animals are common practices among andean communities in South America. Infection by Trypanosoma cruzi occurs when the animals live in triatomine-infested houses or yards. The preventive effect of a vaccine consisting of cultured T. cruzi killed by freezing and thawing plus saponin was tested both in mice and in the guinea pig ecosystem. Resistance against T. cruzi challenge in mice was improved by increasing the trypomastigote/epimastigote ratio in live attenuated vaccines but not in killed parasite vaccines. Although the killing of attenuated parasites sharply reduced their immunogenicity for mice, a protective effect against natural T. cruzi infection was detected in guinea pigs. A total of 88 guinea pigs were vaccinated in four intradermal sites on three occasions. Eighty controls received similar inoculations of culture medium plus saponin. All animals were kept in a triatomine-infested yard. Parasitemia was studied with the capillary microhematocrit method. After an exposure time averaging 4 months, natural T. cruzi infection occurred in 55% (44/80) of the controls and in 33% (29/88) of the vaccinated group (P less than 0.01). The number of highly parasitemic guinea pigs was also significantly decreased (6/80 vs 0/88, P less than 0.01). Thus, immunizing protocols which are only partially protective against artificial callenge with T. cruzi may nevertheless constrain the exchange of parasites between natural hosts and vectors.
Assuntos
Doença de Chagas/veterinária , Cobaias/parasitologia , Doenças dos Roedores/prevenção & controle , Trypanosoma cruzi/imunologia , Vacinas de Produtos Inativados , Animais , Doença de Chagas/prevenção & controle , Reservatórios de Doenças , Congelamento , Insetos Vetores , Camundongos , Triatoma , Vacinação/veterinária , Vacinas AtenuadasRESUMO
It has been found that a) a large rodent population exists in the area of the Kingston and St. Andrew Corporation. b) serious economic loss is caused by rats and mice; c) the high incidence of infestation poses a serious threat to health d) public awareness is high but the attitudes and practices of the citizens towards rodent control is not commensurate with this awareness; e) that control measures now employed by private citizens, pest control operators and the health authorities are still inadequate and unco-ordinated, hence expectation of any significant abatement of the nuisance is extremely remote under present circumstances; f) that poor sanitation, with particular reference to collection, storage and disposal of refuse - can be regarded as the single most important factor influencing rodent infestation: the presence of uncontrolled garbage contributes directly to the incidence of rats and mice. Health education must be stressed if rodent eradication is to be achieved as well as the encouragement of the use of private pest control operators. (AU)