Genomic insights into ESBL-producing Escherichia coli isolated from non-human primates in the Peruvian Amazon.

Introduction: Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae are on the WHO priority pathogens list because they are associated with high mortality, health-care burden, and antimicrobial resistance (AMR), a serious problem that threatens global public health and should be addressed through the One Health approach. Non-human primates (NHP) have a high risk of acquiring these antibiotic-resistant bacteria due to their close phylogenetic relationship with humans and increased anthropogenic activities in their natural environments. This study aimed to detect and analyze the genomes of ESBL-producing Escherichia coli (ESBL-producing E. coli) in NHP from the Peruvian Amazon. Materials and methods: We collected a total of 119 fecal samples from semi-captive Saguinus labiatus, Saguinus mystax, and Saimiri boliviensis, and captive Ateles chamek, Cebus unicolor, Lagothrix lagothricha, and Sapajus apella in the Loreto and Ucayali regions, respectively. Subsequently, we isolated and identified E. coli strains by microbiological methods, detected ESBL-producing E. coli through antimicrobial susceptibility tests following CLSI guidelines, and analyzed their genomes using previously described genomic methods. Results: We detected that 7.07% (7/99) of E. coli strains: 5.45% (3/55) from Loreto and 9.09% (4/44) from Ucayali, expressed ESBL phenotype. Genomic analysis revealed the presence of high-risk pandemic clones, such as ST10 and ST117, carrying a broad resistome to relevant antibiotics, including three blaCTX-M variants: blaCTX-M-15, blaCTX-M-55, and blaCTX-M-65. Phylogenomic analysis confirmed the clonal relatedness of high-risk lineages circulating at the human-NHP interface. Additionally, two ESBL-producing E. coli strains were identified as EPEC (eae) and ExPEC according to their virulence profiles, and one more presented a hypermucoviscous phenotype. Discussion: We report the detection and genomic analysis of seven ESBL-producing E. coli strains carrying broad resistome and virulence factors in NHP from two regions of the Peruvian Amazon. Some of these strains are closely related to high-risk pandemic lineages previously reported in humans and domestic animals, highlighting the negative impact of anthropogenic activities on Amazonian wildlife. To our knowledge, this is the first documentation of ESBL-producing E. coli in NHP from the Amazon, underscoring the importance of adopting the One Health approach to AMR surveillance and minimizing the potential transmission risk of antibiotic-resistant bacteria at the human-NHP interface.

Occurrence and Genomic Characterization of mcr-1-Harboring Escherichia coli Isolates from Chicken and Pig Farms in Lima, Peru.

Resistance to colistin generated by the mcr-1 gene in Enterobacteriaceae is of great concern due to its efficient worldwide spread. Despite the fact that the Lima region has a third of the Peruvian population and more than half of the national pig and poultry production, there are no reports of the occurrence of the mcr-1 gene in Escherichia coli isolated from livestock. In the present work, we studied the occurrence of E. coli carrying the mcr-1 gene in chicken and pig farms in Lima between 2019 and 2020 and described the genomic context of the mcr-1 gene. We collected fecal samples from 15 farms in 4 provinces of Lima including the capital Lima Metropolitana and recovered 341 E. coli isolates. We found that 21.3% (42/197) and 12.5% (18/144) of the chicken and pig strains were mcr-1-positive by PCR, respectively. The whole genome sequencing of 14 mcr-1-positive isolates revealed diverse sequence types (e.g., ST48 and ST602) and the presence of other 38 genes that confer resistance to 10 different classes of antibiotics, including beta-lactamase blaCTX-M-55. The mcr-1 gene was located on diverse plasmids belonging to the IncI2 and IncHI1A:IncHI1B replicon types. A comparative analysis of the plasmids showed that they contained the mcr-1 gene within varied structures (mikB-mcr1-pap2, ISApl1-mcr1-pap2, and Tn6330). To the best of our knowledge, this is the first attempt to study the prevalence of the mcr-1 gene in livestock in Peru, revealing its high occurrence in pig and chicken farms. The genetic diversity of mcr-1-positive strains suggests a complex local epidemiology calling for a coordinated surveillance under the One-Health approach that includes animals, retail meat, farmers, hospitals and the environment to effectively detect and limit the spread of colistin-resistant bacteria.

Genomic Characterization of Salmonella Typhimurium Isolated from Guinea Pigs with Salmonellosis in Lima, Peru.

Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) is one of the most important foodborne pathogens that infect humans globally. The gastrointestinal tracts of animals like pigs, poultry or cattle are the main reservoirs of Salmonella serotypes. Guinea pig meat is an important protein source for Andean countries, but this animal is commonly infected by S. Typhimurium, producing high mortality rates and generating economic losses. Despite its impact on human health, food security, and economy, there is no genomic information about the S. Typhimurium responsible for the guinea pig infections in Peru. Here, we sequence and characterize 11 S. Typhimurium genomes isolated from guinea pigs from four farms in Lima-Peru. We were able to identify two genetic clusters (HC100_9460 and HC100_9757) distinguishable at the H100 level of the Hierarchical Clustering of Core Genome Multi-Locus Sequence Typing (HierCC-cgMLST) scheme with an average of 608 SNPs of distance. All sequences belonged to sequence type 19 (ST19) and HC100_9460 isolates were typed in silico as monophasic variants (1,4,[5],12:i:-) lacking the fljA and fljB genes. Phylogenomic analysis showed that human isolates from Peru were located within the same genetic clusters as guinea pig isolates, suggesting that these lineages can infect both hosts. We identified a genetic antimicrobial resistance cassette carrying the ant(3)-Ia, dfrA15, qacE, and sul1 genes associated with transposons TnAs3 and IS21 within an IncI1 plasmid in one guinea pig isolate, while antimicrobial resistance genes (ARGs) for ß-lactam (blaCTX-M-65) and colistin (mcr-1) resistance were detected in Peruvian human-derived isolates. The presence of a virulence plasmid highly similar to the pSLT plasmid (LT2 reference strain) containing the spvRABCD operon was found in all guinea pig isolates. Finally, seven phage sequences (STGP_Φ1 to STGP_Φ7) were identified in guinea pig isolates, distributed according to the genetic lineage (H50 clusters level) and forming part of the specific gene content of each cluster. This study presents, for the first time, the genomic characteristics of S. Typhimurium isolated from guinea pigs in South America, showing particular diversity and genetic elements (plasmids and prophages) that require special attention and also broader studies in different periods of time and locations to determine their impact on human health.

Carnivore protoparvovirus 1 in Peruvian dogs: Temporal/geographical and evolutionary dynamics of virus.

Canine parvovirus (CPV) has been recognized all around the world as the causal agent of a contagious and highly mortal disease in domestic dogs. In Peru, the infection is endemic and unvaccinated animals and puppies are the most at risk. In order to analyze viral diversity and determine the evolutionary genetic relationships and transmission dynamic of Peruvian CPV-2, were collected during the period of 2016-2017 rectal swabs from puppies with parvovirosis compatible symptoms. Viral DNA was amplified by PCR using primers that flanked the ends of the viral genome and sequenced by Illumina Miseq platform. Twenty-six genomic sequences (NSP1-VP1) of CPV from several districts in Lima Metropolitan area were obtained. The VP2 gene analysis demonstrated the presence of the New CPV-2a, New CPV-2b and 2c variants. The phylodynamic analysis of the viral genomes determined that all Peruvian sequences were clustered into a big clade named South American clade that emerged from the west region of Europe (Italy). The Time to the Most Recent Common Ancestor (TMRCA) of the South American clade was dated to 1993. Peruvian sequences were distributed into three subclades, and the 92% of these sequences were related to Ecuadorian CPV-2. The results suggests that three independent introduction events of virus from other countries could have occurred, in two of these events, CPV-2 from Ecuador were introduced in Peru in 2003 and 2009, and another introduction event, in 2000, from Europe. Overall, these results indicate a viral genetic relationship between Peruvian with Ecuadorian and European virus, and the circulation of several viral subpopulations in Lima Metropolitan.

Canine parvovirus types 2a and 2c detection from dogs with suspected parvoviral enteritis in Peru.

Canine parvovirus type 2 (CPV-2) has been reported worldwide as the main agent related to acute hemorrhagic enteritis of high morbidity and variable mortality in puppies. The detection and characterization of this virus is essential to understand the etiology of the disease and to develop control measures. To characterize the virus circulating in Peruvian dogs and to provide new insights into the local diversity of CPV-2, rectal swabs from 39 puppies with clinical symptoms and with no history of previous vaccinations were analyzed. Total DNA was extracted by fast boiling method, and PCR and sequencing were performed using specific primers that amplify a 1316 bp fragment corresponding to the VP2 gene of CPV-2. CPV-2 was detected in 62% of the analyzed samples. The sequencing of PCR product was possible in 9 samples, which were identified as type 2a (4 samples) and type 2c (5 samples). A phylogenetic analysis of both variants circulating in Peruvian dogs showed similarities to Equatorian and Uruguayan strains. This work constitutes the first report about genetic characterization of CPV-2 in Peru.

Presence and molecular characterisation of Giardia and Cryptosporidium in alpacas (Vicugna pacos) from Peru.

The presence of Giardia and Cryptosporidium was investigated in 274 faecal samples of alpacas (Vicugna pacos) from 12 herds from Peru by immunofluorescence microscopy and PCR amplification and sequencing of fragments of the ssu-rRNA and ß-giardin genes from Giardia spp., as well as the ssu-rRNA gene from Cryptosporidium spp. A total of 137 samples (50.0%) were positive for Giardia spp., and 12 samples (4.4%) for Cryptosporidium spp. In ten samples (3.6%), co-infection by both pathogens was found. Herd prevalence was found to be 91.7% (11/12 herds) for Giardia and 58.3% (7/12 herds) for Cryptosporidium. Regarding the age of the animals, although Giardia was detected in animals as young as 1 week, the prevalence increased with age, reaching 80% by 8 weeks. Similarly, the highest percentage of Cryptosporidium detection (20%) was also found in the 8 week-old group. By PCR, 92 of the 274 analysed samples were positive for Giardia. Sequencing of the amplicons showed the existence of Giardia duodenalis assemblage A in 67 samples; G. duodenalis assemblage E in 24 samples; and inconsistent results between the two molecular markers used in a further sample. Cryptosporidium was only detected by PCR in 3 of the 274 samples; Cryptosporidium parvum was identified in two samples and Cryptosporidium ubiquitum in one sample. This study is the first performing molecular characterisation of both parasites in Peruvian alpacas, and the first report of C. ubiquitum in this host. The identification of G. duodenalis assemblage A, C. parvum and C. ubiquitum, suggests that zoonotic transmission of these enteropathogens between alpacas and humans is possible.

Estudio clínico, serológico y patológico de una cepa velogénica del virus de Newcastle en codornices (Coturnix coturnix japonica) / Clinical, srelogical and pathological study of a Newcastle velogenic virus strain in quails (Coturnix, coturnix japonica)

Se determinó la susceptibilidad, el efecto patológico, y la respuesta serológica inducida por una cepa velogénica viscerotrópica del virus de la enfermedad de Newcastle (vvENC). Para este fin, se criaron 40 codornices japónicas (Coturnix coturnix japonica) hembras, donde 20 se inocularon vía nasal y ocular con una cepa de vvENC y 20 se usaron como grupo control. Para el análisis histopatológico y recuperación viral se tomó muestras de tejidos e hisopados de cloaca de las aves inoculadas y del grupo control; y para detectar anticuerpos contra el virus de la ENC mediante la prueba de inhibición de la hemaglutinación (IH) se tomó muestras de sangre durante 5 semanas posteriores al desafío. En el 40% de las aves inoculadas se registraron signos severos, así como mortalidad del 20% de las aves inoculadas. Del mismo modo, se registraron lesiones macroscópicas y microscópicas en los animales inoculados. El grupo desafiado registró un incremento en los niveles de anticuerpos a partir de los 7 días postinoculación (PGT 6.1), alcanzando el mayor PGT a los 14 días post inoculación (PGT 29.9), mientras que en el grupo de aves control no se registró seroconversiones. La recuperación viral se logró a partir de los hisopados de cloaca de las aves afectadas por la enfermedad. El grupo control no registró signos de enfermedad ni cambios histopatológicos.

The objective of the study was to determine the susceptibility, pathological effect, and serological response induced by a velogenic viscerotropic strain of Newcastle disease virus (vvNDV). For this purpose, 40 female quails (Coturnix coturnix japonica) were raised. Twenty were nasal and ocular inoculated with a vvNDV strain and 20 remained as a control group. Tissue samples and cloacae swaps of all birds were collected for histopathology analysis and virus isolation. Blood samples were collected during 5 weeks after the viral challenge to detect antibodies against NC virus using the hemaglutination inhibition (HI) test. In 40% of the inoculated birds was observed severe clinical signs and 20% mortality. The inoculated group registered an increase in the antibody level after day 7 post inoculation (MGT 6.1), reaching the highest level at 14 days post inoculation (MGT 29.9), whereas the control group did not register seroconversions. The viral isolation was obtained from cloacae swabs of the affected animals. The control group did not show signs of illness or histopathologycal changes.

Contribución al estudio del parasitismo gastrointestinal en guanacos (Lama guanicoe cacsilensis) / Contribution to the study of gastrointestinal parasitism in the guanaco (Lama Guanicoe Cacsilensis)

El propósito del presente estudio fue identificar las especies de parásitos gastrointestinales que afectan al guanaco peruano y determinar los niveles de parasitismo de las poblaciones evaluadas. Se obtuvieron 132 muestras de heces frescas de guanacos silvestres pertenecientes a nueve poblaciones ubicadas en seis departamentos del Perú: Comunidad Campesina de Huallhua (Ayacucho), Reserva Nacional de Calipuy (La Libertad), Comunidad Campesina de Chavín (Ica), Reserva Nacional Salinas y Aguada Blanca y distritos de Machaguay y Yarabamba (Arequipa), distrito de Quilahuani y Comunidad Campesina de Vila Vilani (Tacna), y distrito de La Capilla (Moquegua). Las muestras fueron procesadas mediante técnicas coproparasitológicas de flotación, sedimentación, cultivo de larvas, Baerman y biometría de larvas y ooquistes. Se identificaron ocho especies de nematodos: Graphinema aucheniae, Bunostomun sp., Ostertagia sp., Trichuris sp, Cooperia sp., Nematodirus sp., Mazamastrongylus peruvianus y Trichostrongylus sp. y cuatro especies de Eimeria: E. lamae, E. alpacae, E. punoensis y E. macusaniensis. Todas las poblaciones se encontraban con al menos un guanaco parasitado, presentando en general cargas bajas y variando las frecuencias de parasitismo gastrointestinal de una población a otra, dependiendo del hábitat y de la proximidad a herbívoros domésticos.

The aim of this study was to identify the species of gastrointestinal parasites affecting the Peruvian guanaco and to determine the levels of parasitism in the populations under evaluation. For this purpose, 132 fresh faecal samples were collected from nine populations of wild guanacos located in six departments of Peru: Huallhua Community in Ayacucho; Calipuy National Reserve in La Libertad; Chavín community in Ica; Salinas and Aguada Blanca National Reserve, and Machaguay and Yarabamba districts in Arequipa, Quilahuani district and Vila Vilani community in Tacna, and La Capilla district in Moquegua. Samples were processed by the coproparasitological techniques of flotation, sedimentation, larvae culture, and Baerman, and biometry of larvae and oocysts. Eight species of nematodes were identified: Graphinema aucheniae, Bunostomun spp., Ostertagia spp., Trichuris spp., Cooperia spp., Nematodirus spp., Mazamastrongylus peruvianus and Trichostrongylus spp., and four Eimeria species: E. lamae, E. alpacae, E. punoensis and E. macusaniensis. All guanaco populations had at least one animal with parasites, showing low parasite burden in general, and with a variation in the frequency of gastrointestinal parasitism from one population to another, depending on the habitat and the proximity to other domestic herbivores.

Determinación del sexo por ADN en cinco especies de guacamayos / Sex determination by ADN in five macaw species

La determinación del sexo en aves de especies silvestres es de vital importancia para tomar medidas de conservación. En especies donde no existe dimorfismo sexual, es necesario contar con una prueba de sexaje alternativo a los métodos quirúrgicos. En este sentido, con la finalidad de estandarizar una prueba para la determinación del sexo en guacamayos, se desarrolló y evaluó una prueba molecular que consistió en el análisis de ADN mediante la Reacción en Cadena de la Polimerasa (PCR). Para ello, se procedió a la extracción de ADN a partir de muestras de sangre cinco especies de guacamayos (Ara ararauna, Ara chloroptera, Ara macao, Ara militaris y Propyrrhura couloni). A través de la técnica de PCR y el uso de primers específicos, se amplificó regiones conservadas (exones) y secuencias de regiones no conservadas (intrones) del gen chd (Chromodomain-helicase-DNA-binding protein), presentes en ambos cromosomas sexuales (Z y W), que permiten diferenciar hembras (chd-ZW) de machos (chd-ZZ). Para la amplificación, se optimizaron las condiciones y los ciclos de PCR. Se pudo detectar dos fragmentos entre 300-400 pares de bases en aves hembras y solamente uno en especies machos. Se observó 100 por ciento (31/31) de correspondencia entre el sexaje por métodos convencionales y por análisis de ADN. La prueba molecular fue posteriormente utilizada para sexar a 28 guacamayos de sexo desconocido, incluyendo 11 aves de la especie peruana Propyrrhura couloni.

Determination of sex in wild birds is crucial in developing conservation plans for threatened species. The absence of sexual dimorphism in birds makes impossible to determine sex based on physical characteristics and sexing has traditionally depended upon surgical methods which are highly stressful for the animals. The present study had the purpose of developing of a noninvasive DNA test for sex determination in macaws (guacamayos). Blood samples from five species (Ara ararauna, Ara chloroptera, Ara macao, Ara militaris y Propyrrhura couloni) were studied. DNA was extracted and specific primers were used to amplify both exons and introns of the chd (chromo-helicase-DNA-binding) gene located on the sex chromosomes of all birds. Females are identified by chd-ZW on the W chromosome and males by chd-ZZ on the Z chromosome. The amplification was carried out by the optimization of the conditions and the PCR cycles. Two fragments of 300-400 bp were detected in female birds and one in males. Sex determined by conventional methods in 31 birds agreed with DNA results. The molecular test was also used to sex 28 macaws of unknown sex, including 11 Propyrrhura couloni.

Evaluación de un método numérico de medición del diámetro de la fibra de alpaca / Evaluation of a numerical method for measuring the diameter of the alpaca fiber

El presente estudio evalúa el método de medición de diámetro de la fibra de alpaca mediante el procesamiento de imagen digital, Digital Image Fibre Diameter Analisis (DIFDA), desarrollado en el Centro Internacional de la Papa, y lo compara con los valores obtenidos mediante dos métodos de medición convencionales: Lanámetro (Microscopio de Proyección) y OFDA (Optical Fibre Diameter Analysis). El DIFDA requiere de una evaluación del proceso de imágenes digitales obtenidas mediante un escáner de transparencias y negativos de una muestra de fibra de alpaca preparada en porta slides. Este método presenta una opción de procesamiento de imagen digital completa o otra de secciones dentro de la imagen digital, donde los resultados se expresan en promedio, desviación estándar y coeficiente de variación. Un total de de 206 muestras de fibra de alpacas del fundo Pacomarca, Puno, fueron evaluadas. Los valores promedio de diámetro de las fibras fueron de 21.74 ± 3.03, 21.64 ± 3.58 y 21.74 ± 4.01 según los métodos DIFDA, Lanámetro y OFDA, respectivamente; sin haber diferencia significativa entre promedios. El coeficiente de correlación de Pearson entre DIFDA con el lánametro fue de 0.87 y con OFDA fue de 0.84. La medición del diámetro puede realizarse procesando la imagen digital completa, a partir de tres secciones de 1000 x 1000 píxeles, o desde cinco secciones de 500 x 500 píxeles. Se concluye que no existe diferencia significativa entre los resultados de DIFDA y de los métodos Lanámetro y OFDA, por lo que su uso puede ser de utilidad en programas de mejoramiento animal que requieren medición continua del diámetro de fibras.

This study presents the statistical evaluation of a digital image alpaca fibre diameter measurement method, Digital Image Fibre Diameter Analysis (DIFDA). This method developed in the International Potato Center (CIP) requires an evaluation of the fibre sample digital image process, prepared in slides covers and taked from a scanner of negatives and films. DIFDA presents two options for fibre diameter measurement process: Digital image complete and sections of the digital image. The results of the fibre sample are mean fibre diameter, standard deviation and coefficient of variability. The objective was to test and compare the mean fibre diameter values obtained by DIFDA with the values from two conventionals methods: Projection Microscope and OFDA (Optical Fibre Diameter Analysis). In adition, DIFDA’s process options were evaluated. Two hundred six alpaca fibre samples from Pacomarca Farm, Puno, were evaluated. The mean fibre diameter samples values, measured by commercials methods, Projection Microscope and OFDA, were, 21.64 ± 3.58 and 21.74 ± 4.0, respectively. The mean fibre diameter reported for DIFDA was 21.74 ± 3.03. No statistical differences between the methods were detected. The Pearson’s correlation coefficient for DIFDA and Projection Microscope and for DIFDA and OFDA was 0.87 and 0.84, respectively. The process of DIFDA could be done in the complete digital image option, or using three or more sections for the dimention of 1000 x 1000 pixels, or five or more sections for the dimention of 500 x 500 pixels. The conclutions were that the DIFDA’s results showed no statistical significative differences between neither the Projection Microscope’s nor the OFDA’s results. Consequently, this measurement method would be used satisfactorily in breeding programs that requires continuos fibre measurement.

Enfermedades causadas por priones y la encefalitis espongiforme bovina / Prion diseases and bovine spongiform encephalitis

Prion infections of the Central Nervous System has received considerable attention due to its zoonotic disease threat. It is caused by a unique agent that lacks nucleic acid and its pathology results from progressive deposition of proteinase K resistant misfolded protein (PrPsc) in the brain. The prion protein (PrPc) normally is expressed in different types of cells but mainly in the glial cell and neuronal synapsis. It is clear that conformational changes from PrPc to PrPc are the key to understand prion disease and the nature of the transmission capability of the agent. It is suspected that prion infection is able to cross species barriers. It is speculated that scrapie agent was able to produce BSA and the new variant of CJD as consequence of ingestion of BSA infected beef cattle. There is no antemortem diagnostic test for histopathological changes (vacuolization in the neuropile and neurons) or prion detection by immunochemistry using antibodies against resistant to proteinase K.

Las enfermedades priónicas han recibido una considerable atención en los últimos años debido al riesgo potencial de ser zoonóticas. Son producidas por agentes únicos pues, aparentemente, carecen de ácidos nucleicos y su patología es producto de acumulaciones progresivas de anómalas conformaciones proteicas en el tejido nervioso. La proteína priónica, generalmente referida como PrPsc, es una forma anormal de una proteína celular (PrPc), que se diferencian por su sensibilidad a la digestión de la proteinasa K. La proteína priónica normal se expresa en diferente tipo de células, pero se concentra principalmente dentro de las glías y la sinapsis neuronal. Se considera que el cambio de la conformación de PrPc a PrPsc es fundamental en el entendimiento de las enfermedades priónicas y de la naturaleza de la transmisibilidad de la gente. Se sospecha que las proteínas priónicas infecciosas son capaces de cruzar la barrera de las especies, pues de especula que el prión productor de la enfermedad del scrapie en ovejas fue capaz de producir la encefalitis espongiforme bovina (EEB) y una nueva forma (variante) de una enfermedad en humanos (Creutzfeldt-Jakob), a consecuencia del consumo de productos de animales infectados por la EEb. No existe una prueba de diagnóstico antemortem que puede detectar animales portadores de la infección. Los métodos diagnósticos existentes detectan cambios histopatológicos (vacuolizaciones en el neuropilo y neuronas) o detectan el prión mediante técnicas immuhistoquímicas, utilizando anticuerpos contra la proteína resistente a la proteinasa K.

Seroprevalencia de Toxoplasma gondii en alpacas de comunidades de la provincia de Canchis, Cusco / Seroprevalence of Toxoplasma gondii in alpacas communities Canchis province, Cusco

El objetivo del estudio fue cuantificar la seroprevalencia de Toxoplasma gondii en alpacas de comunidades alpaqueras de los distritos de Maranganí, Pitumarca, Checacupe y San Pablo, en la provincia de Canchis, Cusco. Se recolectaron 272 muestras de sangre en marzo del 2003 para la detección de anticuerpos contra T. gondii mediante la prueba de inmunofluorescencia indirecta (IFI). Se encontró una seroprevalencia moderada de 35.7 ± 5.7 por cento. No se encontró asociación entre las variables distrito, sexo, raza y la respuesta a la prueba de IFI. Sin embargo, se encontró una asociación significativa entre la edad y la respuesta a la prueba. La seroprevalencia del presente estudio concuerda con resultados obtenidos en camélidos sudamericanos en otras zonas del sur del Perú.

The objective of the present study was to determine the seroprevalence of Toxoplasma gondii in alpacas of communities from the districts of Maranganí, Pitumarca, Checacupe and San Pablo, located in the province of Canchis, department of Cusco. A total of 272 blood samples were collected in March 2003, for the detection of antibodies against T. gondii by the indirect immunofluorescence test (IFAT). The resulting seroprevalence was 35.7 ± 5.7 per cent, without significant differences due to district, sex, and breed; however, there was a significant association between age and IFAT value. The results of the present study agreed with other studies conducted in South American camelids in different localities in the south of Peru.

Cinética de la infección por Brucella ovis en carneros durante una época de empadre / Kinetics of Brucella ovis infection in rams during breeding season

Con la finalidad de estudiar la evolución de la infección a Brucella ovis en condiciones de campo, una punta de carneros de plantel (n=250) de una empresa ovejera de la sierra central del país fueron examinados clínica y serológicamente durante el período de empadre (2 meses). Al inicio del empadre ningún animal tenía evidencias clínicas de la enfermedad (epididimitis), pero el 58.7 por ciento era positivo a la prueba de ELISA indirecta. Al término del empadre el 28.4 por ciento de los reproductores tuvo que ser eliminado por lesiones testiculares evidentes, en tanto que los exámenes de ELISA demostraron que 74.4 por ciento de los carneros eran positivos a la prueba. El estudio evidenció una rápida evolución de un estado de animal seropositivo a animal clínicamente enfermo. En estas condiciones de campo, los exámenes clínicos no son suficientes medidas para controlar la infección, por lo que es fundamental realizar exámenes serológicos y eliminar a todo reactor positivo. Si no se practica estas recomendaciones, es mejor buscar otras alternativas de control incluyendo el uso de vacunas.

The evolution of Brucella ovis infection was documented clinically and serologically in a flock of 250 field reared rams from a large sheep production company in the central sierra of Peru. Although no clinical evidence of Brucellosis (epididymitis) was detected at the start of a 2-month breeding campaign, 58.7 of the animals were positive to the indirect ELISA test. At the end of the breeding season, 74.4 percent tested positive using indirect ELISA and 28.4 percent of the animals had to be eliminated due to testicular lesions. These results demonstrate rapid evolution of the bacterial infection from seropositive to clinical manifestation, indicating that reliance on clinical observation alone is insufficient to control the infection under field conditions. Serological testing is necessary in order to identify and eliminate all positive reactors. If this procedure is not followed, alternative control alternatives such as vaccines should be employed to control the disease.

Uso de la REV-1 en el control de la brucelosis ovina en una empresa ovejera del Perú / Using the REV-1 in the control of ovine brucellosis in sheep company in Peru

Se evaluó el efecto de la vacuna Rev-1 en el control de la brucelosis ovina causado por Brucella ovis en una empresa lanar de la sierra central del Perú. El uso de esta vacuna fue reintroducida en 1996, después de un lapso de 5 años. Al momento de la evaluación, la empresa mantenía el 86.3 por ciento de carneros vacunados (3,284/3,804) y el 100 por ciento de carnerillos vacunados (n=1,811). La evaluación consistió en exámenes clínicos testiculares a toda la población de reproductores machos (n=5,615) durante la campaña de esquila del año 2000. Paralelamente, se evaluó niveles de infección en 320 muestras sanguíneas (214 de carneros y 106 de carnerillos), detectando anticuerpos específicos para la Brucella ovis mediante la prueba de inmunodifusión en gel de agarosa (AGID). Los exámenes testiculares revelaron prevalencias de lesiones de epididimitis en tasas de 89.4 x 10 mil en la población adulta (carneros) y 38.6 x 10 mil en la población de jóvenes (carnerillos). Estas prevalencias son significativamente inferiores a las encontradas antes de la reintroducción de la vacuna, en la que se detectaron prevalencias de 817 x 10 mil en carneros y 241 x 10 mil en carnerillos, encontrándose una asociación directa entre el uso de la vacuna y la disminución progresiva de la prevalencia de epididimitis. Asimismo, la prevalencia de la infección global en la población de machos disminuyó significativamente desde 1,186.4 x 10 mil en 1996 a 531.2 x 10 mil en el año 2000; pero con niveles altos de infección en la población de carneros vacunados (635.8 x 10 mil). La población de carneros vacunados muestra una relativa alta prevalencia de la enfermedad clínica (97.4 x 10 mil) comparada con la población no vacunada (38.5 x 10 mil), pero con menor tasa de infección (635.8 x 10 mil) que los no vacunados (1,219.5 x 10 mil).

In 1996, after a 5 year hiatus, the use of the Rev-1 vaccine was reintroduced to control ovine brucellosis (Brucella ovis) in a large sheep company of the central Peruvian Andes, and by the year 2000, 86.3 percent of the rams (3,284 of 3,804) and 100 percent of the young males (n=1,811) were vaccinated. During the shearing campaign for year 2000, testicles of the entire male breeding population (n=5,615) were examined manually and 320 blood samples (214 rams and 106 yearlings) were taken for AGID testing to determine the presence of Brucella ovis antibodies. Epididymitis lesions were found in 89.4 x 10,000 of the rams and 38.6 x 10,000 of the yearlings, compared to 817 x 10,000 for rams and 214 x 10,000 for yearlings prior to reintroduction of Rev-1 vaccination. The progressive reduction in epididymitis was directly related to vaccination. The level of infection was found 1,186.4 x 10,000 in 1996 decreasing to 531.2 x 10,000 in 2000, but infection levels remained high in the vaccinated population (635.8 x 10,000). Clinical expression of the disease was 38.5 x 10,000 in unvaccinated males compared to 97.4 x 10,000 in vaccinated animals, but infection rates were considerably lower in vaccinated (635.8 x 10,000) than in unvaccinated (1,219 x 10,000) males. These results clearly demonstrate the efficaciousness of Rev-1 in controlling epididymitis in rams.

Procesos proliferativos en la Región Cefálica de los ovinos / Proliferative processes in the cephalic region of sheep

Con la finalidad de caracterizar macro e histopatológicamente procesos proliferativos en la región cefálica se estudiaron catorce casos en ovinos adultos hembras procedentes de una organización lanar de la Sierra Central del país. Las características macro y microscópicas de estas lesiones correspondieron a procesos neoplásicos (n=10), crecimiento proliferativo benigno (n=1) y los 3 restantes a procesos inflamatorios (dermatitis crónica). Los procesos neoplásicos se encontraban afectando pabellones de la oreja (n=5), globo ocular (n=4) y la parte dorsal de la nariz (n=1). El caso proliferativo (papiloma hiperqueratótico) y las dermatitis crónica se encontraron comprometiendo la oreja. Macroscópicamente los tumores presentaban crecimiento exofítico, de forma semiovalada, papilomatosa, semicircular, pero todos tenían superficie exudativa y necrosante. Los procesos neoplásicos no estuvieron asociados con metástasis, pero histológicamente evidenciaron diversos grados de diferenciación celular. De los 10 casos, 6 correspondieron al grado I (bien diferenciado) y 4 al grado II (moderadamente diferenciado). Todos los animales afectados con tumores presentaban una ligera leucocitosis caracterizada generalmente por una neutrofilia, y en 2 casos se observó una ligera a moderada linfopenia.

Macro and histopathological analyses of proliferative processes in the cephalic region of adult female sheep from a large enterprise in the central sierra of Peru are reported. Of the 14 cases studied, 10 corresponded to neoplasias, one to benign proliferative growth and 3 to inflammatory processes (chronic dermatitis). The neoplasias effected the ear lobe (n=5), eye ball (n=4) and the nostril (n=1), while the proliferative (hyperkeratotic papilloma) and chronic dermatitis cases were jeopardizing the ear lobe. Macroscopically the tumors presented exophytic semi-oval, papillomatous and semicircular growths, and all had exudate and necrotized surfaces. The neoplasias were not associated with metastasis, but histologically demonstrated diverse degrees of cellular differentiation. Of the 10 neoplasias, 6 corresponded to degree I (well differentiated) and 4 to degree II (moderately differentiated) . All the animals effected with tumors presented slight leukocytosis, generally characterized by neutrophilia, and slight to moderate lymphopenia was found in 2 of the 10 cases.