ABSTRACT
Several animal models exist to evaluate the immunogenicity and protective efficacy of candidate Shigella vaccines. The two most widely used nonprimate models for vaccine development include a murine pulmonary challenge model and a guinea pig keratoconjunctivitis model. Nonhuman primate models exhibit clinical features and gross and microscopic colonic lesions that mimic those induced in human shigellosis. Challenge models for enterotoxigenic Escherichia coli (ETEC) and Campylobacter spp. have been successfully developed with Aotus nancymaae, and the addition of a Shigella-Aotus challenge model would facilitate the testing of combination vaccines. A series of experiments were designed to identify the dose of Shigella flexneri 2a strain 2457T that induces an attack rate of 75% in the Aotus monkey. After primary challenge, the dose required to induce an attack rate of 75% was calculated to be 1 × 10(11) CFU. Shigella-specific immune responses were low after primary challenge and subsequently boosted upon rechallenge. However, preexisting immunity derived from the primary challenge was insufficient to protect against the homologous Shigella serotype. A successive study in A. nancymaae evaluated the ability of multiple oral immunizations with live-attenuated Shigella vaccine strain SC602 to protect against challenge. After three oral immunizations, animals were challenged with S. flexneri 2a 2457T. A 70% attack rate was demonstrated in control animals, whereas animals immunized with vaccine strain SC602 were protected from challenge (efficacy of 80%; P = 0.05). The overall study results indicate that the Shigella-Aotus nancymaae challenge model may be a valuable tool for evaluating vaccine efficacy and investigating immune correlates of protection.
Subject(s)
Aotidae , Dysentery, Bacillary/prevention & control , Shigella Vaccines/immunology , Administration, Oral , Animals , Antibodies, Bacterial/blood , Diarrhea/microbiology , Diarrhea/prevention & control , Disease Models, Animal , Immunoglobulin A/blood , Immunoglobulin G/blood , Shigella Vaccines/administration & dosage , Shigella Vaccines/adverse effectsABSTRACT
El estudio tuvo por objetivo obtener valores hematológicos de referencia de la tortuga motelo (Geochelone denticulata). Se utilizaron 44 individuos mantenidos en cautiverio en la ciudad de Iquitos-Perú. Se colectó la sangre por punción de la vena subcarapacial y se determinó recuento de glóbulos rojos (RGR), recuento de glóbulos blancos (RGB), hematocrito (Ht), hemoglobina (Hb), recuento diferencial de leucocitos e índices eritrocíticos. La temperatura cloacal y el peso corporal se emplearon como referencia del estado de salud. Los valores promedio fueron: RGR 0.44 x 10uL, RGB 7.82 x 10uL, Ht 20.3%, Hb 7.0 g/dl, VCM 502.7 fl, HCM 171.4 pg, CHCM 34.1 g/dl. El recuento diferencial de leucocitos fue: Heterófilos 55.6%, Linfocitos 25.5%, Eosinófilos 15.8%, Basófilos 1.5%, Monocitos 0.4%, Azurófilos 1.2%. Los resultados coinciden con los intervalos de referencia documentados para la especie.
The objective of the study was to obtain hematological referential values for Geochelone denticulata tortoise. Blood samples of 44 tortoises, maintained in captivity in Iquitos city, Peru, were collected by puncture of the subcarapacial vein. Blood parameters under evaluation were red blood cell number (RBC), white blood cell number (WBC), hematocrit (Ht), hemoglobin (Hb), differential leukocyte counts and erythrocyte indexes. Cloacal temperature and body weight were used as a reference for health status. The average values were: RBC 0.44 x 10mL, WBC 7.82 x 10mL, Ht 20.3%, Hb 7.0 g/dl, MCV 502.7 fl, MCH 171.4 pg, MCHC 34.1 g/dl. Leukocyte differential counts were: Heterophils 55.6%, Lymphocytes 25.5%, Eosinophils 15.8%, Basophils 1.5%, Monocytes 0.4%, Azurophils 1.2%. Results were similar to values reported for the species.
Subject(s)
Animals , Hematology , Turtles/blood , Reference ValuesABSTRACT
El objetivo del presente estudio fue determinar la presencia de Trypanosomasp. en sajinos en cautiverio de las zonas de Iquitos y Moyobamba. Se colectó muestras de sangre de 40 sajinos procedentes de tres zoocriaderos con edades entre 3 meses y 2 años. Las muestras se procesaron con las técnicas de microcapilar o técnica de Woo y del frotis sanguíneo delgado. No se halló la presencia de Trypanosomasp. en las muestras examinadas, y, posiblemente, la baja sensibilidad de las técnicas afectó los resultados. La técnica de evaluación de riesgo por simulación Monte Carlo (programa @Risk) indicó que el 95% de las observaciones analizadas se encontraron en un intervalo de 0.006 a 0.854% y que la probabilidad de encontrar la infección real en sajinos provenientes de Iquitos y Moyobamba se encuentra en un rango promedio de infección de 0.02%.
The objective of the present study was to determine the presence of Trypanosomasp. in collared peccaries reared in captivity in Iquitos and Moyobamba area. Blood samples were collected from 40 animals from 3 months to 2 years of age. Samples were processed by the microcapillary or Woo technique and the blood smear. None of the samples resulted positive to Trypanosoma sp., and probably the low sensitivity of the techniques affected the results. The Monte Carlo risk analysis (@Risk) indicated that the probability to obtain an infected animal in the Moyobamba and Iquitos area was 0.02% and that 95% of the samples were within an interval of 0.006 a 0.854%.
Subject(s)
Animals , Mammals , Parasitemia , Polymerase Chain Reaction , Trypanosoma , PeruABSTRACT
El objetivo del presente estudio fue detectar la presencia de Salmonella sp. en 30 tortugas motelo (Geochelone denticulata) de un zoocriadero de la zona de Iquitos, Perú. Las muestras de heces se obtuvieron por hisopado rectal y se procesaron mediante pruebas de cultivo bacteriológico y bioquímicas. El 6.7% de las muestras fueron positivas a Salmonellasp., donde de la tipificación dio como resultado Salmonella enterica subespecie enterica serotipo typhimurium.
The objective of the present study was to detect the presence of Salmonella spp. in 30 motelo turtles (Geochelone denticulata) in a zoo of the Iquitos region, Peru. Fecal samples were obtained by rectal swaps and processed by bacteriological and biochemical cultivation tests. The results showed that 6.7% of the samples were positive to Salmonella spp. and the typing indicated Salmonella enterica subspecies enterica serotype typhimurium.
Subject(s)
Animals , Animal Husbandry , Enterobacteriaceae , Salmonella , Turtles , Bacterial Typing Techniques , PeruABSTRACT
The objetive of this study was to detect antibodies against vesicular stomatitis virus (VSV) in collared peccaries (Tayassu tajacu) from farms of Iquitos and Pucallpa, Peru. Blood samples were collected in animals olders than 6 months of age (pregnant females were not included) from a farm in Iquitos (n = 21) and from four farms in Pucallpa (n = 47), for detection of antibodies against Indiana 1 and New Jersey serotype of VSV by viral neutralization test. No specific antibodies against both serotypes of VSV were detected, indicating that the peccaries were not exposed to VSV, and suggesting absence of the infection in those animals.
Subject(s)
Animals , Antibodies, Viral , Vesicular Stomatitis/prevention & control , Swine/virology , PeruABSTRACT
The objective of this study was to establish reference serum values for bilirrubin (total and direct), alanine amino transferase (ALT), aspartate amino transferase (AST), alkaline phosphatase, cholesterol, total protein, albumin, urea, and creatinine in healthy collared peccary (Tayassu tajacu) kept under captivity in the Amazonian jungle of Peru (Loreto, Iquitos). A total of 28 adult animals (14 males and 14 females) were used. Blood samples (7 ml) were collected from the safen vein. Serum values were: Total bilirrubin: 0.7± 0.2 mg/dl; direct bilirrubin: 0.2 ± 0.1 mg/dl; ALT: 26.5 ± 9.1 UI/l; AST: 15.9 ± 8.4 UI/l; alkaline phosphatase: 27.5 ± 15.5 UI/l; cholesterol: 94.4 ± 20.2 mg/dl; total protein: 8.5 ± 1.1 g/dl; albumin: 4.4 ± 0.5 g/dl; urea: 58.1 ± 11.1 mg/dl; and creatinine: 2.2 ± 0.5 mg/dl. It was concluded that serum values were similar to other results reported in the literature and without statistical differences due to sex.
